Coxarthrosis: Clinical Guidelines

List of Abbreviations

ACR – American College of Rheumatology

ALT – alanine aminotransferase

AST – aspartate aminotransferase

anti-CCP – antibodies to cyclic citrullinated peptide

DMARDs – disease-modifying antirheumatic drugs

HA – hyaluronic acid

GC – glucocorticoids

GI – gastrointestinal tract

CA – coxarthrosis

CT – computed tomography

HDL – high-density lipoproteins

LDL – low-density lipoproteins

medicamentos – medications

PT – physical therapy

ICD-10 – International Classification of Diseases, 10th Revision

MRI – magnetic resonance imaging

NSAIDs – nonsteroidal anti-inflammatory and antirheumatic drugs from group M01A according to the ATC classification

ASU – avocado-soybean unsaponifiables

OA – osteoarthritis

PIP – proximal interphalangeal joints

MCPJs – metacarpophalangeal joints

RD – radioisotope diagnostics

RCTs – randomized controlled trials

RF – rheumatoid factor

SYSADOA – symptomatic slow-acting drugs for osteoarthritis

ESR – erythrocyte sedimentation rate

CVS – cardiovascular system

Hip – hip joint

TG – triglycerides

US – ultrasound examination

PTL – physical therapy treatment

COX – cyclooxygenase

EGD – esophagogastroduodenoscopy

TENS – transcutaneous electrical nerve stimulation

JR – joint replacement

AUSCAN – Australian/Canadian Hand Osteoarthritis Index

ESCEO – European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis

EULAR – European Alliance of Associations for Rheumatology

Terms and Definitions

Hip arthroplasty is a high-tech surgical procedure that involves replacing the hip joint with an artificial one.

Total hip arthroplasty – a type of arthroplasty involving the implantation of both the femoral and acetabular components of the endoprosthesis.

Cemented hip arthroplasty – a type of arthroplasty combining the installation of both components using bone cement.

Cementless hip arthroplasty – a type of arthroplasty combining the installation of both cementless components.

Hybrid/antihybrid arthroplasty – a type of hip arthroplasty combining the installation of one component with cement fixation and the other with cementless fixation.

Osteophytes in the hip region are marginal bony growths along the edge of the acetabulum and the border of the femoral head and neck.

Contracture – limitation of the range of motion in a joint.

Impingement is the abnormal contact of articulating bones within a joint, accompanied by pain, discomfort, and radiographic signs of structural changes in the articulating bones at the site of abnormal contact.

1. Brief information on the disease or condition

1.1 Definition of the disease or condition

Coxarthrosis is a heterogeneous group of diseases of various etiologies with similar biological, morphological, clinical manifestations, and outcomes, based on the involvement of all joint components: cartilage, subchondral bone, synovial membrane, ligaments, capsule, as well as periarticular muscles [1, 2, 137, 138, 139].

1.2 Etiology and pathogenesis of the disease or condition (group of diseases or conditions)

OA is a complex pathological process affecting all joint structures (cartilage, synovial membrane, subchondral bone, periarticular tissues), arising from the interaction of age-related, hormonal, genetic, and environmental factors [1, 138, 139]. Depending on etiological factors, primary (idiopathic) and secondary (mechanoinduced) coxarthrosis are distinguished, usually caused by incongruency of the articular surfaces.

Primary osteoarthritis of the hip is one of the heterogeneous disorders whose exact cause remains unclear. To date, no single factor responsible for the development of hip osteoarthritis has been identified. According to modern concepts, the development of coxarthrosis occurs due to the combined action of various biological and mechanical factors, such as metabolic disorders, genetic or hereditary predisposition, age, vascular developmental anomalies, overweight, adverse environmental and occupational conditions, as well as comorbid conditions [2-7]. In addition, factors contributing to the development of hip OA should include the pathologically altered process of reparative regeneration of joint structures in response to a damaging agent [1, 6-8, 138].

The triggering mechanism for the development of hip OA is usually changes in the parameters and morphology of the hyaline articular cartilage. Numerous studies have established that cartilage degeneration increases as the disease stage progresses, with degeneration of the acetabular cartilage contributing to a similar process in the femoral head, which manifests as cyst formation [8-10]. Hyaline cartilage is affected much more frequently in the acetabulum than in the femoral head: in 72.2% and 16.7% of cases, respectively. Furthermore, the anterosuperior surface of the acetabulum is mainly affected [11, 12].

Hip OA is characterized by a chronic progressive course that leads to disability and loss of working capacity in patients, altering their entire lifestyle, which makes the treatment of this pathology not only a medical but also a social issue [13].

One of the variants of secondary coxarthrosis occurring against the background of congenital hip developmental defects after conservative and surgical treatment is dysplastic coxarthrosis [14, 15, 17-20]. The study of the etiopathogenesis of this disease has shown that the main factors contributing to its development are congenital progressive biomechanical imbalance and local overloads of the chondral and subchondral structures of the joint. The higher the degree of mechanical overloads associated with underdevelopment of the mutual support zones of the femoral head and the acetabular roof, the faster the failure of the joint's regenerative capacities occurs [16].

M.M. Kamosko (2005) views dysplastic hip OA as a tissue structure response to the imbalance between the load and the resistance to it, first of the articular cartilage and then of all joint structures as a result of anatomical and functional mismatches. Moreover, the severity of the degenerative-dystrophic process is determined by the localization of hyperpressure zones, changes in the size of the weight-bearing surface of the joint, and the duration of chronic overload.

Often, secondary hip OA may occur against the background of femoroacetabular impingement (FAI) or as a result of acetabular fractures (post-traumatic coxarthrosis) [21-24, 29]. Moreover, based on the analysis of specialized scientific publications in recent years, it develops in almost 57% of cases after the specified injuries, and 26% of specialized patients may develop heterotopic ossification and avascular necrosis of the femoral head [24-28].

Features of the etiology and course of coxarthrosis in children

According to large national arthroplasty registries, the cause of early end-stage coxarthrosis in children in 10–33% of cases is major pediatric hip orthopedic diseases (dysplasia, slipped capital femoral epiphysis, Legg-Calvé-Perthes disease) [227, 228, 229, 230, 231].

The development of dysplastic coxarthrosis in children is, in the vast majority of cases, caused by the formation of residual subluxation due to the lack of concentric reduction of the femoral head into the acetabulum and/or the occurrence of secondary deformations of the proximal femur due to post-reduction ischemic necrosis of the femoral head of varying severity during conservative treatment in the first year of the child's life [232, 233, 234, 235, 236]. The development of coxarthrosis in Legg-Calvé-Perthes disease is associated with the deformation of the femoral head itself and the development of femoroacetabular impingement [237, 238, 239]. The development of coxarthrosis in slipped capital femoral epiphysis is associated with chronic displacement of the proximal femoral epiphysis relative to its neck. Even a minor residual deformation at the head-neck junction of the femur will contribute to femoroacetabular impingement and, accordingly, lead to early coxarthrosis [240, 241].

In the absence of pathogenetic intervention, hip OA is fundamentally no different from its course in patients over 18 years of age. The main feature is the possibility of regressing its stage after restoring correct radiographic-anatomic and biomechanical relationships between the femoral head and the acetabulum [242].

1.3 Epidemiology of the Disease or Condition

Primary hip OA is one of the most common degenerative-dystrophic diseases of the hip joint. Nevertheless, according to the National Collaborating Centre for Chronic Conditions, drawing conclusions about the true prevalence of hip OA is extremely difficult [1]. On the one hand, this is due to the lack of a unified definition and multiple variable diagnostic criteria for the disease [2-5, 30-33, 35, 36]. For example, in a study conducted in Ireland in the age group over 55 years, a diagnosis of hip OA was made in the majority of patients, but in many of them, the disease was asymptomatic and was merely an incidental radiographic finding [34]. At the same time, it should be noted that radiographic diagnostics is often insufficient for making a diagnosis. In a study conducted back in 1989, J.S. Lawrence et al. showed that in patients aged 24 to 74 years, radiographic signs of the disease were observed in 12% of cases, whereas pathomorphological examination revealed marked degenerative-dystrophic joint changes in the complete absence of radiographic changes [50].

On the other hand, the absence in some countries, including the Russian Federation, of a unified registry including all cases of arthroplasty or other surgical treatment methods in patients suffering from various variants of hip OA makes it impossible to establish a comprehensive epidemiological picture of this disease in these countries.

Congenital hip dysplasia and, consequently, secondary coxarthrosis are among the most common disorders: the prevalence of this pathology in various populations ranges from 0.1 to 20% [37]. Furthermore, congenital hip dislocation is observed in 0.1–0.4% of newborns, whereas subluxation occurs 10 times more frequently. Factors contributing to hip dysplasia include breech presentation, female fetal gender, firstborn status, family history, hormonal factors, and ethnicity. Specifically, 80% of cases of dysplasia are detected in girls, which can be attributed to the action of additional estrogens produced by the female fetus, leading to increased laxity of the ligamentous apparatus. Moreover, the left hip is affected three times more often than the right, and bilateral dysplasia is observed in 20–25% of cases [38, 39, 53, 54, 55, 56].

The geographical distribution of hip dysplasia is of particular interest. In Europe, this pathology is 13 times more common than in the USA, occurring predominantly among Germanic and Slavic populations. In Southeast Asia, the development of congenital hip dislocation is extremely rare. This can be explained by the custom common in these countries of carrying infants on the back with their legs abducted, which promotes normal hip joint development. The high incidence of congenital hip dislocation among indigenous North American populations is due to the tradition of tight swaddling [40]. In Russia and the CIS, a similar trend is observed in the Nenets Autonomous Okrug (8.7–10.9%) and among the population of the North Caucasus (3.4%).

According to WHO projections, the incidence of secondary coxarthrosis caused by trauma of various origins will increase due to the rising life expectancy of the population [41, 46]. In the United States, 300,000 proximal femur fractures are registered annually [42, 43, 45.]. In Russia, the incidence of hip fractures has reached 61 per 100,000 population (90,000 per year), and among individuals over 75 years of age, the proportion of femoral neck fractures is 4 times higher [44-46].

According to a number of authors, post-traumatic secondary coxarthrosis occupies one of the leading places in the structure of major joint pathology among the adult population in various regions of Europe, ranging from 6.5% to 25%. In St. Petersburg, this figure is 28.7 per 10,000 residents. In individuals over 35 years of age, the incidence of post-traumatic coxarthrosis reaches 10.8% and increases to 35.4% among those over 85 [46-48]. The urgency of the problem is determined by the constantly increasing rate of injuries and diseases of the hip joint caused by technological progress on the one hand, and more advanced capabilities for early diagnosis of diseases on the other hand, which applies to both the working-age group and older populations.

The social significance of coxarthrosis, in addition to its high prevalence, is determined by the high probability of disability in these patients. The proportion of disabled individuals due to coxarthrosis of various origins accounts for 20 to 30% of those disabled due to joint diseases [43, 45, 49, 50]. Among the structure of traumatism, one of the most severe injuries is acetabular fractures, accounting for 7 to 22% of all musculoskeletal injuries. These injuries subsequently require reconstructive surgery or total hip arthroplasty and are characterized by high rates of permanent patient disability [25, 27, 51, 52, 59-64].

1.4 Features of Coding the Disease or Condition

M16 – Coxarthrosis

M16.0 – Primary coxarthrosis

M16.1 – Other primary coxarthrosis

M16.2 – Bilateral coxarthrosis resulting from dysplasia

M16.3 – Other dysplastic coxarthrosis

M16.4 – Post-traumatic bilateral coxarthrosis;

M16.5 – Other post-traumatic coxarthrosis.

M16.6 – Other bilateral secondary coxarthrosis

M16.7 – Other secondary coxarthrosis

M16.9 – Coxarthrosis, unspecified

M24.6 – Ankylosis of joint

M24.7 – Protrusio acetabuli

1.5 Classification of the disease or condition

1.5.1 By etiology:

1. Primary coxarthrosis (idiopathic) – occurs without any apparent external causes.

2. Secondary coxarthrosis – history indicates one or more etiological factors (sequelae of femoroacetabular impingement (FAI), hip dysplasia, consequences of trauma, etc.) [51, 55-58]

1.5.2 By the degree of articular cartilage alteration (severity of arthrosis)

Recommended for use in clinical practice are the three-stage classification by N.S. Kosinskaya (1961) [65] and the four-stage classification by J. Kellgren and J. Lawrence [66]. The classification by D. Tönnis [88, 89] also exists (see App. G1).

1.6 Clinical presentation of the disease or condition

The leading clinical symptom of hip joint arthrosis is pain, which worsens with movement or load on the joint, especially towards the end of the day, upon cooling, and in damp weather. In the early stages of coxarthrosis, pain subsides after a period of rest. Furthermore, the intensity of the pain syndrome does not directly correlate with the stage of the disease and the degree of morphological changes in the hip joint. As the disease progresses, the pain becomes constant. Complaints of a limp, the need for an additional walking aid, difficulty going up or down stairs, and getting up from a chair or armchair are associated with the pain. As the pathological process progresses, a limitation of the range of motion in the hip joint (contracture) appears.

2. Diagnostics, medical indications and contraindications for diagnostic methods

Criteria for diagnosis/condition establishment: historically, the diagnosis of coxarthrosis is based on the results of clinical and radiological examinations [67, 68].

2.1 Complaints and Anamnesis

• To examine a patient with suspected coxarthrosis, a thorough medical history taking and a full clinical examination are recommended [1, 69, 71].

CUD CLOE 5Level of Clinical Usefulness / Strength of Recommendation C (Level of Evidence 5)

Comments: Patient complaints in hip osteoarthritis depend on the stage of the pathological process [69, 70]. Hip pain in coxarthrosis occurs during weight-bearing or movement and intensifies after walking. The pain is localized primarily in the groin area. It may radiate to the anterior and lateral surfaces of the thigh, the front of the knee joint, and rarely to the gluteal region. Stiffness develops, and in later stages, hip contractures occur, while functional impairments lead to a reduced ability for self-care and a shorter walking distance [69, 71]. In addition, shortening of the lower limb on the affected side is frequently observed (in unilateral OA) [1, 12, 68, 71].

2.2 Physical Examination

• For examination purposes, it is recommended to assess the patient's general condition, the function of the affected joints, and measure their height and body weight [1, 69, 72-78].

CUD CLOE 5Strength of Recommendation C (Level of Evidence – 5).

Comments: The function of the affected hip joint is recommended to be assessed by the degree of limitation of the range of motion in the hip joint, the state of periarticular muscles and the muscles of the lower limb as a whole, changes in the axis and shortening of the limb, as well as the patient's gait. When assessing gait, it is recommended to pay attention to the degree of the patient's weight-bearing on the leg, the presence of a limp, and the distance the patient can walk. It is also recommended to pay special attention to the patient's facial expression and assess the degree of discomfort they may experience [72-76].

The patient's examination is recommended to be carried out in vertical and horizontal positions, as well as during walking [77, 78]. In addition, it should be noted that in dysplastic coxarthrosis, excessive anteversion and a valgus femoral neck associated with acetabular aplasia provide these patients in the early stages of arthrosis development with a wide range of motion in the hip joint, often exceeding the normal range. Therefore, such patients are often keen on dancing or yoga. Hip joint stiffness, characteristic of most variants of coxarthrosis, develops much later [13, 69, 71]

• For examination purposes, it is recommended to assess disease severity and daily life activity [1, 68, 69, 72-78, 100, 101, 102].

CUD CLOE 5Strength of Recommendation C (Level of Evidence – 5)

Comments: All patients with coxarthrosis (especially in the late stages of the disease) show a decrease in daily life activity and a change in the overall quality of life [101]. The concept of daily activity is recommended to include the ability to climb stairs and use public transport, free movement, the use of an additional walking aid, and the ability to put on socks and shoes.

2.3 Laboratory Diagnostics

Currently, there is no "gold standard" for laboratory diagnosis of coxarthrosis, which is due to the very low concentration of biochemical markers in blood and urine, as well as the overlay of concurrently occurring pathological processes in other joints of the patient.

Comments: Laboratory tests are primarily prescribed to assess the condition of the patient's internal organs and systems and for differential diagnosis [1, 67 – 76].

2.4 Instrumental Diagnostics

• All patients are recommended to undergo hip radiography as the simplest and most traditional method of examining patients with hip osteoarthritis to assess the stage of disease progression and determine its etiological type [12, 68, 69, 71, 79, 80, 149].

GoR ALoE 2Grade of Recommendation A (Level of Evidence 2).

Comments:

It is advisable to perform radiography of the pelvis and hip joint in anteroposterior and lateral projections.

For correct radiological diagnosis and interpretation of the stage of hip osteoarthritis development, it is recommended to:

1. Radiological characteristics of the acetabulum.

2. Radiological characteristics of the proximal femur.

3. Evaluation of radiological signs of the relationship between the acetabulum and the femoral head: a) Wiberg angle; b) Shenton's line; c) vertical center-edge angle; d) degree of femoral head coverage.

Radiological characteristics of the acetabulum: [12, 79]

In the early stages of hip osteoarthritis, the acetabulum is generally normoplastic. However, as the pathological process progresses, its depth may increase due to marginal osteophytes or post-traumatic changes. In addition, a decrease in bone tissue quality (in the form of sclerosis, cystic restructuring, etc.) around the acetabulum may be observed. In cases of primary hip osteoarthritis, the acetabulum has a regular shape and normal anteversion. However, in the presence of post-traumatic changes, the shape and position of the acetabulum can vary significantly. In this case, in the early stages of the disease, the mechanical center of rotation is not displaced. As the disease progresses, lateralization of the acetabulum may increase due to the formation of a central osteophyte. Furthermore, as the pathological process develops in the superior parts of the acetabular wall, bone cysts may form [12, 79].

Radiological characteristics of the femur:

Primary hip osteoarthritis is characterized by normoplasia with a gradually narrowing or straight femoral canal, normal anteversion and length of the femoral neck, and a normal location of the greater trochanter. The femoral head is usually of normal shape and size, but in late stages of the disease, it may enlarge due to marginal osteophytes. With disease progression, cystic restructuring of the trabecular bone tissue is frequently detected in the femoral head.

In the first stage of the disease, sclerosis of the femoral head and acetabulum increases, accompanied by a slight narrowing of the joint space and some sharpening of its margins. Subsequently, unfavorable load distribution in the joint from the biomechanical perspective of hip movements, caused by osteophyte formation, induces a gradual lateral displacement of the femoral head, leading to excessive pressure on a limited area of the acetabulum and the head itself. As a result, on the one hand, cystic restructuring of the bone tissue develops at the site of load concentration (typically symmetrical areas in the femoral head and the acetabular roof); on the other hand, ossifications develop at the site of constant tension of the hip joint capsule—in the attachment area of the labrum along the acetabular rim, as well as in the inferior parts of the femoral head and acetabulum.

Evaluation of radiological signs of the relationship between the acetabulum and the femoral head:

Wiberg angle (CE angle) indicates the degree of immersion of the femoral head into the acetabulum. In adults, the normal Wiberg angle ranges from 26° to 35°. It is calculated by measuring the angle between two lines: 1 – a line passing through the center of the femoral head, perpendicular to the transverse axis of the pelvis, and 2 – a line passing from the center of the femoral head to the most superolateral point of the sclerotic weight-bearing zone of the acetabulum.

Shenton's line is an arcuate line drawn along the inner margin of the femoral neck to the upper margin of the obturator foramen. A break in Shenton's line on radiographs is a sign of dysplasia and certain other hip joint disorders.

The vertical center-edge angle is formed between the lines connecting the edges of the acetabulum and the center of the femoral head to the midpoint of the femoral neck. Its normal value ranges from 70° to 90°.

Degree of femoral head coverage – the ratio between the transverse dimension of the femoral head and the distance from its medial margin to the lateral margin of the acetabulum [12, 68, 71, 79, 80]. Values from 70% to 90% coverage are considered normal.

• To clarify the nature of pathological changes in hip tissues and for differential diagnosis, including various variants of hip osteoarthritis, computed tomography of the joint and/or magnetic resonance imaging of the joints (single joint) may be recommended [69, 71, 150, 151].

GPR CLoE 4Grade of Recommendation C (Level of Evidence 4).

2.5 Other Procedures

When radiological examination is performed correctly, the identification and staging of hip osteoarthritis generally do not present difficulties [1, 12, 68-70, 79].

Comments: Diseases with a similar clinical presentation include inflammatory arthritis, characterized by complaints of pain or stiffness during sleep or at rest, and pain or stiffness in other joints: wrists, elbows, knees, and shoulders [33, 69, 81].

Inflammatory arthritides include: rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, gouty arthritis, pseudogout (pyrophosphate arthropathy), reactive arthritis, and connective tissue disease-associated arthritis such as systemic lupus erythematosus. Another similar condition that frequently masks pathological conditions in the hip region is lumbosacral osteochondrosis and various forms of radiculopathy, which are characterized by lower back pain radiating to the lower extremities and, specifically, to the hip region [1, 12, 69, 70, 71, 79].

3. Treatment, including drug and non-drug therapies, diet therapy, and pain management

The management of patients with hip osteoarthritis (OA) is lifelong, aiming to reduce pain, preserve articular cartilage, stabilize or improve the function of affected joints, prevent the progression of functional disability, improve health-related quality of life, and prevent and reduce adverse effects from pharmacotherapy. Furthermore, patients with hip osteoarthritis require continuous clinical monitoring.

Treatment options include conservative (non-pharmacological and pharmacological), injection, and surgical (joint-sparing and joint-replacing) methods, the choice of which depends on the severity of clinical manifestations and the stage of hip osteoarthritis development [1, 12, 69, 70, 79, 82].

• Conservative (non-surgical) treatment is recommended at all stages of hip osteoarthritis development, whereas surgical treatment is primarily indicated in the late stages of disease progression (stage III according to the Kosinskaya classification and stage III or IV according to the Kellgren and Lawrence classification), although it may also be indicated in earlier stages in the presence of severe, refractory pain syndrome. Conservative treatment may also be performed after surgery on one hip joint to treat the contralateral hip joint also affected by osteoarthritis [1, 12, 38, 69, 70, 71, 79, 82].

GCR CLOE 5Grade of Recommendation C (Level of Evidence – 5).

Comments: In some cases, the treatment modality and scope may be determined not only by the stage of the pathological process, but also by the patient's age, presence of comorbid conditions (comorbidity), involvement pattern (unilateral or bilateral), limb length discrepancy, biomechanical relationships of joint components, and insufficiency or deformity of the acetabular roof [1, 38].

3.1 Conservative Treatment

Conservative treatment for hip osteoarthritis consists of non-pharmacological and pharmacological interventions. Since the pathogenesis of hip osteoarthritis remains insufficiently understood to date, etiology-based (etiotropic) therapy for this disease has not been practically developed.

The main goals of conservative treatment in hip osteoarthritis are: effective control of disease symptoms, primarily pain in the affected hip joints; preservation and improvement of their function; reduction of the severity of inflammatory responses in these joints; and prevention of articular cartilage degradation [12, 79, 99].

3.1.1 Non-pharmacological therapy

• All patients are recommended to modify sports/physical activities and unload the affected hip joint: avoiding dynamic and static factors (running, prolonged walking, jumping, heavy lifting, maintaining a monotonous working posture, etc.); wearing shoes with well-cushioned soles; using an additional support such as a cane or crutch in the hand contralateral to the affected joint [1, 12, 79, 82, 83, 153, 164, 165, 166, 167].

GCR CLOE 5Grade of Recommendation C (Level of Evidence – 5).

Comments: in patients with OA, excessive joint load, including that caused by anatomical changes and impaired biomechanical parameters, leads to increased symptoms and disease progression. The use of a cane and properly selected footwear can reduce joint load and improve biomechanical parameters, which in turn leads to pain relief and decreased functional impairment [67–71].

• All patients with hip osteoarthritis may be recommended physical exercises to reduce pain, strengthen lower limb muscles, preserve the function of the affected hip joint, improve weight-bearing capacity, walking, self-care, and overall quality of life [1, 12, 79, 82, 83, 103]. Therapeutic exercise for joint diseases and injuries, post-isometric muscle relaxation, hydrokinesitherapy for joint diseases and injuries, as well as manual therapy techniques for joint diseases in the early stages of coxarthrosis progression are recommended to improve mobility in the affected joints [216, 217, 218].

GGR BLOE 1Grade of Recommendation B (Level of Evidence – 1).

Comments: Physical exercise in OA helps reduce pain and preserve joint functional activity [82, 83, 102, 103], especially when combined with educational programs. In hip osteoarthritis, strength exercises (isometric, resistance exercises) help reduce joint pain [102, 103]. Therapeutic exercise combined with manual therapy in the early stages of hip osteoarthritis provides the greatest efficacy, as does hydrokinesitherapy, which is due to the analgesic effect of thermal factors, improved regional blood circulation, weight reduction, and more complete relaxation of spastic muscles [218]. The use of muscle-strengthening exercises, stretching and flexibility/mobility exercises, resistance and neuromuscular exercises, as well as aerobic exercises can reduce pain intensity, improve function, and enhance quality of life in patients with early stages of progression. In chronic musculoskeletal pain, including hip osteoarthritis, dosed walking significantly reduces disease symptoms [82, 83]. Contraindications for therapeutic exercise in patients with hip osteoarthritis must also be considered: uncontrolled arrhythmia, 3rd-degree heart block, recent ischemic changes on the electrocardiogram, unstable angina.

Comments: The main goal of educational programs is to increase the efficacy of therapy by actively involving the patient in the treatment process. Educational programs have a positive impact on disease symptoms, improve joint function, quality of life, and treatment adherence [74, 82, 83, 84].

Comments: The choice of a specific physiotherapy technique depends on the clinical symptoms of the disease and comorbid conditions. Pulsed magnetic field therapy can be considered as an additional safe and non-invasive therapeutic option to reduce musculoskeletal pain symptoms in osteoarthritis and improve the functional mobility of the damaged joint [18]. Mineral water baths reduce musculoskeletal pain symptoms, improve joint mobility, and enhance patients' quality of life [19].

Comments: Despite varying researcher opinions regarding the impact of isolated weight loss on slowing down the progression of hip osteoarthritis symptoms, there is evidence that weight loss in overweight patients improves their functional capabilities, specifically improving mobility in the affected hip joint. Furthermore, individual scientific publications indicate that the severity of pain syndrome in hip osteoarthritis decreases in direct proportion to weight loss [1, 12, 79, 82, 83, 84]. It is also known that hip osteoarthritis can be caused by mechanical factors, including joint load, and the prevalence of the condition correlates with the severity of obesity [1, 12, 79]. Therefore, reducing excess weight is considered desirable both for alleviating disease symptoms and for improving the overall health status of such patients. In clinical studies, pain reduction and functional improvement of the affected hip joint were observed to a greater extent in patients who used a combination of a weight-loss diet and a specialized hip exercise program compared to those who used either weight-loss diets alone or therapeutic exercise alone [12, 79, 82].

3.1.2 Drug therapy

Etio-pathogenetic pharmacotherapy for hip osteoarthritis has not yet been developed, so medical treatment is symptomatic in nature.

• Patients with predominantly early stages of coxarthrosis, regardless of the severity of the pain syndrome, are recommended to receive symptomatic slow-acting drugs in osteoarthritis (SYSADOA):

• Chondroitin sulfate, glucosamine, and their combinations for effective alleviation of hip osteoarthritis symptoms and achieving a structure-modifying effect with long-term use [168, 99, 169, 170].

GOM ALOE 1Grade of Recommendation A (Level of Evidence – 1).

• Preparations based on avocado and soybean unsaponifiables (INN: avocado and soybean oil unsaponifiables) for the relief of coxarthrosis symptoms in patients aged 18 years and older at a dose of 300 mg daily [171].

GOM ALOE 1Grade of Recommendation A (Level of Evidence – 1).

• Diacerein for the relief of hip osteoarthritis symptoms and achieving a structure-modifying effect with long-term use in patients aged 18 years and older [184, 185, 186].

Level of Evidence BLevel of Confidence 2Level of recommendation B (level of evidence – 2).

• Preparations based on a bioactive concentrate from small marine fish from the M09AX group "Other drugs for disorders of the musculoskeletal system" (trade name Alflutop) or glycosaminoglycan-peptide complex to reduce the severity of hip osteoarthritis symptoms in patients aged 18 years and older [172].

LoE BGoE 2Level of Recommendation B (level of evidence – 2).

Comments: currently, chondroitin sulfate, glucosamine and their combinations, as well as preparations based on avocado and soybean unsaponifiables and diacerein, are isolated into a separate group of symptomatic slow-acting drugs (SYSADOA), which according to the Anatomical Therapeutic Chemical (ATC) classification belong to group M01AX – "Other non-steroidal anti-inflammatory and antirheumatic products" and are considered basic therapy for osteoarthritis [168, 170, 173, 174, 175]. It should be especially noted that these drugs have varying evidence bases for their efficacy in osteoarthritis.

The most studied drugs in terms of efficacy and safety in osteoarthritis are chondroitin sulfate, glucosamine, and their combinations. These drugs possess not only analgesic and anti-inflammatory effects, but are also capable of slowing the progression of hip osteoarthritis and delaying joint replacement surgery. A pronounced symptomatic effect from SYSADOA therapy develops 8 to 12 weeks after initiation, but for a structure-modifying effect, the duration of treatment must be at least two years [170, 175, 176, 177, 178]. The daily therapeutic dose of glucosamine is 1500 mg. The therapeutic dose calculation for glucosamine is based on studies conducted with glucosamine sulfate. The standard oral administration regimen for chondroitin sulfate in osteoarthritis, including hip osteoarthritis, involves 500 mg twice daily [170]. At the start of therapy to enhance bioavailability and achieve a faster analgesic effect, chondroitin sulfate, glucosamine sulfate, and other SYSADOA drugs in adults can be administered parenterally, for example, as intramuscular injections in accordance with approved product labeling [173, 174, 179].

Unlike NSAIDs, SYSADOA drugs exhibit a carry-over effect for two to four months after treatment cessation. Recent systematic reviews and meta-analyses of randomized clinical trials have confirmed the efficacy of this drug group in patients with osteoarthritis [168, 169], which has led to their inclusion in international clinical guidelines [180]. However, recent meta-analyses indicate that positive efficacy data for original standardized SYSADOA drugs cannot be extrapolated to generics, dietary supplements, and other substances not registered as pharmacological agents [181, 182].

According to meta-analysis data, crystalline glucosamine sulfate significantly reduced pain, improved joint function, and decreased pain scores in osteoarthritis, whereas other forms showed no significant difference compared to placebo in these parameters [183]. This drug also demonstrated efficacy comparable to ibuprofen in relieving pain and improving joint function as early as the second week of use [180]. Other studies showed that glucosamine sulfate delayed joint space narrowing and reduced the need for joint replacement in osteoarthritis patients over an 8-year follow-up period [175, 176, 177]. In a two-year randomized controlled trial, a significant reduction in articular cartilage volume loss, assessed by quantitative MRI, was proven with chondroitin sulfate at a dose of 1200 mg/day in patients with knee osteoarthritis [178].

A recent meta-analysis of the efficacy and safety of a drug based on avocado-soybean unsaponifiables demonstrated a significant symptomatic effect in reducing pain with an adverse event rate comparable to placebo [171]. However, there is no convincing evidence of a structure-modifying effect.

Drugs based on a bioactive concentrate from small marine fish, as well as the glycosaminoglycan-peptide complex indicated for hip osteoarthritis, have also demonstrated symptomatic efficacy in reducing pain in placebo-controlled RCTs [172].

Diacerein is also classified as a SYSADOA; its efficacy in reducing pain severity and preventing joint space narrowing in hip osteoarthritis was until recently considered questionable [184]. However, an international multicenter double-blind comparative study of celecoxib and diacerein conducted in 2019 confirmed the latter's analgesic and anti-inflammatory efficacy in osteoarthritis [185]. There is also evidence of diacerein's structure-modifying effect on articular cartilage in hip osteoarthritis from a long-term three-year study, which also showed good drug tolerability [186]. Therefore, diacerein can be an alternative to NSAIDs in the treatment of hip osteoarthritis, especially in patients with contraindications to such therapy, as it does not cause the adverse events characteristic of NSAIDs. However, one should consider that gastrointestinal adverse events—such as diarrhea, flatulence, and epigastric pain—may occur when prescribing this drug.

• If there is no clinical effect within three months in patients receiving SYSADOA therapy, it is recommended to switch to other drugs within this group or additionally prescribe medications from other pharmacological groups, taking into account the feasibility of a final assessment of SYSADOA efficacy after completing a full treatment course, which typically lasts 5 to 6 months [148].

Level of Evidence BLevel of Confidence 2Level of recommendation B (level of evidence – 2).

• For patients with hip osteoarthritis presenting with moderate to severe pain, to rapidly and effectively reduce pain in the affected hip joints, it is recommended to prescribe nonsteroidal anti-inflammatory drugs (NSAIDs) taking patient comorbidity into account [187, 188, 189].

GOM ALOE 1Grade of Recommendation A (Level of Evidence – 1).

• Continuous use of NSAIDs provides better symptom control in hip osteoarthritis than "on-demand" NSAID dosing [188, 190, 191].

Level of Evidence BLevel of Confidence 2Level of recommendation B (level of evidence – 2).

Comments: The use of nonsteroidal anti-inflammatory drugs (NSAIDs), which possess proven anti-inflammatory and analgesic effects, is considered the mainstay of medical treatment for patients with hip osteoarthritis. NSAIDs at medium and maximum therapeutic doses are not inferior in efficacy to tramadol in treating chronic pain. It should be noted that the clinical efficacy of recommended NSAID doses is approximately equal, with the main difference lying in individual patient response to a specific drug. Therefore, the choice of a drug from this group for target patients should be made individually, considering the pharmacological profile of each medication and the specific patient's comorbidity (concomitant diseases) [192]. All NSAIDs at medium and maximum therapeutic doses have approximately equal analgesic potential with long-term use. A decision to modify NSAID therapy is advisable 5 to 7 days after initiating treatment with drugs from this group (in case of prior analgesic therapy failure).

NSAIDs are characterized by a high frequency of adverse effects, the most common being erosive and ulcerative lesions of the gastrointestinal tract (GIT), cardiovascular complications, and renal dysfunction, peaking by the 4th week. It should be noted that most adverse effects are mild and transient. Nevertheless, GI damage can lead to bleeding and perforation in some cases (incidence ranging from 0.25% to 1.58%). Risk factors for GI adverse effects include age over 65 years, a history of gastric and duodenal ulcer disease or upper GI bleeding, concomitant oral glucocorticoid or antithrombotic therapy, smoking, and alcohol abuse [188].

• The duration of use and dosing regimen of NSAIDs in patients with hip osteoarthritis depend on clinical manifestations and the need for joint pain control [190, 193].

GCR BLOE 2Grade of Recommendation B (Level of Evidence – 2).

Comment: There is no clear data supporting the long-term use of NSAIDs in hip osteoarthritis. These drugs should be used only for pain control and discontinued once significant improvement is achieved. Depending on the clinical situation, NSAIDs may be used in continuous or short courses, as well as on an "on-demand" basis to manage disease exacerbations.

• In patients with a moderate risk of gastrointestinal adverse events (AEs), it is recommended to use NSAIDs whose mechanism involves preferential COX-2 inhibition, or non-selective NSAIDs in combination with proton pump inhibitors (PPIs) [194].

GOM ALOE 1Grade of Recommendation A (Level of Evidence – 1).

• In patients with a high probability of gastrointestinal AEs, it is recommended to use NSAIDs whose mechanism involves preferential COX-2 blockade, in combination with PPIs [194].

GCR BLOE 2Grade of Recommendation B (Level of Evidence – 2).

Comments: NSAIDs whose mechanism involves preferential COX-2 blockade are the drugs of choice in the presence of the following risk factors for adverse events: age over 65 years, history of peptic ulcer disease or gastrointestinal bleeding, concurrent use of GCS or antithrombotic agents, and presence of severe comorbidities.

• In patients aged 18 years and older with a moderate cardiovascular risk, it is recommended to prescribe propionic acid derivatives (naproxen, ibuprofen** (up to 1200 mg/day), and low-dose celecoxib (400 mg once daily) for pain management in hip osteoarthritis [188, 195].

GGR BLOE 1Grade of Recommendation B (Level of Evidence – 1).

• Patients with osteoarthritis and a very high cardiovascular risk are not recommended to be prescribed NSAIDs [189, 195].

GPP ALOE 1Grade of Recommendation A (Level of Evidence – 1).

Comments: Data from recent systematic reviews and meta-analyses on NSAIDs have shown an increased risk of upper gastrointestinal adverse events, particularly in the presence of abdominal pain, across the entire class of coxibs (selective COX-2 inhibitors). These drugs are also associated with an increased risk of cardiovascular (CV) adverse events. Non-selective NSAIDs are characterized by a high risk of adverse events primarily affecting the gastrointestinal tract and a comparatively lower risk of adverse events affecting the cardiovascular system. Therefore, a cautious approach should be taken when prescribing non-selective NSAIDs and coxibs, taking into account individual patient characteristics and limitations on the duration of use: intermittent or course-based therapy to minimize adverse events [107, 189, 192, 196]. If NSAIDs cannot be used for the symptomatic treatment of patients with hip osteoarthritis, the use of SYSADOA drugs with a high safety profile can be considered: chondroitin sulfate, glucosamine sulfate, and others [179].

• Paracetamol** is recommended for reducing or managing pain in patients with osteoarthritis of large joints, including coxarthrosis, in cases of ineffectiveness or contraindications to the use of NSAIDs [266].

Level CLevel 5Level of recommendation evidence C (reliability level of evidence – 5).

Comments: Paracetamol** has long been considered the drug of choice for mild to moderate pain in osteoarthritis (OA) without signs of pronounced inflammation, as its analgesic efficacy was thought to be comparable to NSAIDs. However, subsequent studies have shown not only its low analgesic efficacy, comparable to placebo in OA, but also frequent gastrointestinal and cardiovascular adverse events. Therefore, it can currently be recommended for short courses at a daily dose not exceeding 3.0 g when NSAIDs are ineffective or contraindicated. In addition, this drug should not be prescribed to patients with liver damage and chronic alcoholism.

• Tramadol** is recommended for use in short courses to control severe pain in hip osteoarthritis when prior conservative therapy with NSAIDs is ineffective or contraindicated [198, 199].

GGR BLOE 1Grade of Recommendation B (Level of Evidence – 1).

Comment: Tramadol** is an opioid analgesic that also acts as a selective serotonin reuptake inhibitor. This drug exerts a moderate and dose-dependent analgesic effect in coxarthrosis. The absence of direct ulcerogenic and prothrombotic effects of tramadol makes its administration possible in patients with high risks of gastrointestinal and cardiovascular adverse events. The mechanism of action of tramadol** differs from NSAIDs, making its use appropriate when the latter are ineffective. However, a large number of various adverse events ( nausea, constipation, sleep disturbances, dizziness, potential for developing dependence) and social issues related to the non-medical use of opioids limit the possibilities of using this drug.

• Duloxetine is recommended in patients aged 18 years and older to control severe chronic pain caused by coxarthrosis when prior conservative therapy with NSAIDs has been ineffective, and especially in the presence of signs of central sensitization, neuropathic pain, and/or depression [200, 201].

GCR ALoE 2Grade of Recommendation A (Level of Evidence – 2).

Comments: Duloxetine is an antidepressant from the group of selective serotonin and norepinephrine reuptake inhibitors, and also weakly inhibits dopamine reuptake. The analgesic effect of duloxetine is associated with its influence on central nociceptive mechanisms, which determines its efficacy in neuropathic pain. However, duloxetine can cause various adverse events, so its administration requires careful medical monitoring and careful titration of the effective dose with gradual increases starting from the minimum—30 mg/day [202]. In cases of prolonged chronic pain syndrome in patients with coxarthrosis, especially when signs of neuropathic pain are detected, antiepileptic drugs (anticonvulsants) may also be prescribed.

Specifics of drug therapy for coxarthrosis in children

General approaches to the drug treatment of children with coxarthrosis are generally similar to those in adults. However, special attention should be paid to contraindications for the use of certain pharmaceutical agents in children, as well as their dosages indicated in the instructions for the respective drugs.

3.2 Injection therapy

• In patients with hip osteoarthritis presenting with pain and functional joint impairment, intra-articular injection of synovial fluid substitutes*** based on hyaluronic acid is recommended [1, 69, 96, 99, 156, 157, 158, 203, 204].

GOM ALOE 1Grade of Recommendation A (Level of Evidence – 1).

Comments: Intra-articular administration of hyaluronic acid derivatives can lead to a positive clinical effect of varying severity, the average duration of which is 4 to 6 months or more, varying greatly depending on the physicochemical characteristics of the specific medical device and the clinical features of the patient [205]. After the clinical effect wears off, the injection can be repeated. The use of hyaluronic acid derivatives has a more favorable safety profile than NSAIDs and can be an alternative to the latter in the treatment of hip osteoarthritis, especially in elderly patients and those with high comorbidity. Treatment is generally well tolerated and comparable to placebo in terms of adverse event (AE) risk: pseudogout-like pain occurs very rarely. Comparative studies of hyaluronic acid preparations and glucocorticoids (GCs) in coxarthrosis and gonarthrosis show approximately equal efficacy 4 weeks post-injection and a significantly greater effect of hyaluronans 5 to 13 weeks post-administration [203, 206, 207]. It should be specifically noted that hyaluronic acid preparations should only be administered in the absence of pronounced synovitis (into a "dry" joint).

• In cases of persistent synovitis in patients receiving adequate doses of NSAIDs, intra-articular administration of glucocorticoids is recommended, but no more than once every 3 months, while course-based administration of these drugs should be excluded [208, 209].

Level of Evidence BLevel of Confidence 2Level of recommendation B (level of evidence – 2).

Comments: Intra-articular administration of glucocorticoids provides a strong anti-inflammatory effect, but is associated with a high risk of secondary osteonecrosis and exacerbation of articular cartilage degradation. Therefore, their use is possible in situations where synovitis cannot be controlled with adequate doses of NSAIDs, but no more than once every 3 months. Course-based administration of glucocorticoids in coxarthrosis is not recommended [208, 209].

Comments: A recent meta-analysis of 30 RCTs demonstrated the superiority of intra-articular injections of platelet-rich plasma compared to glucocorticoids, hyaluronic acid preparations, and placebo in patients with gonarthrosis at 3, 6, and 12 months of follow-up [210].

Comments: Currently, there is no convincing evidence of the efficacy of administering autologous stromal vascular fraction and/or autologous bone marrow cells into the hip joint cavity in hip osteoarthritis. Risk factors for adverse events during this procedure include: active infection in the joint area; inflammatory process at the adipose tissue harvest site; hematopoietic disorders in the patient; pregnancy and breastfeeding periods.

3.3 Surgical Treatment

3.3.1 Joint-preserving surgery

According to literature data, performing joint-sparing surgical interventions in the early stages of hip osteoarthritis in most cases allows delaying, and sometimes even completely preventing, the development of severe late-stage disease requiring the implantation of artificial joints during hip replacement surgeries [12, 15, 93 – 95].

• Arthroscopic treatment (arthroscopic joint debridement) is recommended for early stages of primary or secondary hip osteoarthritis with femoroacetabular impingement (FAI) and/or soft tissue damage in the joint area when conservative therapy is ineffective [12, 87, 93 – 95, 219, 221].

Level CLevel 5Level of recommendation evidence C (reliability level of evidence – 5).

Comments: When choosing arthroscopic treatment, it is recommended to take into account: severity of clinical manifestations, patient age, prevalence (unilateral or bilateral) of the lesion, biomechanical and anatomical relationships of the hip joint elements, and the degree of articular cartilage damage [52, 54, 221].

• Corrective pelvic osteotomies (bone reconstruction, pelvic osteotomy) and proximal femoral osteotomies (bone reconstruction, corrective femoral osteotomy) are recommended to be performed in the early stages of secondary coxarthrosis when appropriate indications are present [1, 38, 69, 71, 87, 93–95].

GDR CLE 5Grade of recommendation C (level of evidence – 5)

Comments: According to literature data, early surgical correction of acetabular dysplasia delays the onset of coxarthrosis [88]. Corrective osteotomy in developed dysplastic coxarthrosis leads to pain reduction and restoration of satisfactory (acceptable) function for many years [89]. The goal of osteotomies in hip dysplasia is to restore normal biomechanics by repositioning the articular surfaces [89]. Arthrosis can also be arrested by increasing the load-bearing surface area, as this decreases the load per unit of articular surface [90].

Periacetabular osteotomy can be performed while maintaining the congruence of the femoral head and acetabulum, and has a positive effect on hip joint biomechanics by improving femoral head coverage and reducing the resulting forces acting upon it [13, 91].

Intertrochanteric osteotomy helps improve the biomechanical conditions of hip joint function, which is manifested by a change in the load axis, redistribution of the lever arms of body weight and the pull of surrounding muscles, reduction and more uniform distribution of intra-articular pressure per unit area of the cartilage surface, muscular decompression, and correction of abnormal limb positioning [91].

Proximal femoral osteotomy is a frequent indication aimed at delaying total hip arthroplasty and should not complicate subsequent arthroplasty procedures [91].

3.3.2 Joint-preserving surgery in children with coxarthrosis

The goal of surgical interventions in early stages of dysplastic coxarthrosis is to restore normal biomechanics through rational reorientation of the hip joint articular surfaces [243, 244, 245].

• Triple pelvic osteotomy may be recommended for children with early stages of dysplastic coxarthrosis development, both with functioning and closed Y-shaped cartilage, to positively affect the hip joint by restoring its stability through increased coverage of the femoral head with autologous acetabular cartilage [246, 247, 248, 249].

GPP CLOE 4Grade of Recommendation C (Level of Evidence – 4).

Comments: To achieve the necessary adequate intraoperative correction of the spatial orientation of the acetabulum, it is recommended to use 3D modeling technology with prototyping of personalized guides [250, 251].

The goal of surgical interventions in early stages of coxarthrosis resulting from previous Legg-Calvé-Perthes disease is to improve the sphericity of the femoral head while eliminating the impingement between the aspherical part of the femoral head and the labrum [252].

• Modeling resection, including segmental femoral resection, using the safe surgical hip dislocation technique to prevent avascular necrosis of the femoral head may be recommended for children with coxarthrosis resulting from previous Legg-Calvé-Perthes disease to improve femoral head sphericity and radically eliminate femoroacetabular impingement [252, 253].

GCR CLOE 5Grade of Recommendation C (Level of Evidence – 5).

• Segmental femoral resection, including segmental resection of the femoral head, may be recommended for children with coxarthrosis resulting from previous Legg-Calvé-Perthes disease to eliminate subluxation, improve femoral head sphericity, and enhance hip joint surface congruence while preserving the blood supply to the femoral head [254, 255, 256].

GPP CLOE 4Grade of Recommendation C (Level of Evidence – 4).

The goal of surgical interventions in early stages of coxarthrosis resulting from previous slipped capital femoral epiphysis is to restore the relationships of the epiphysis with both the acetabulum and the metaphysis.

• Bone osteotomy, corrective femoral osteotomy, specifically anterior rotational or rotational-valgus femoral osteotomy, may be recommended for children with coxarthrosis resulting from slipped capital femoral epiphysis to restore normal relationships between the femoral epiphysis and the acetabulum [257, 259].

GCR CLOE 5Grade of Recommendation C (Level of Evidence – 5).

Comments: Corrective anterior rotational (or rotational-valgus) osteotomy is performed at the intertrochanteric level, after which the proximal femoral fragment is rotated anteriorly and the distal fragment internally [257, 258, 259].

The modified Dunn procedure allows for the restoration of the femoral epiphysis relationships not only with the acetabulum, but also with the metaphysis. Surgical intervention must be performed in strict accordance with the protocol proposed by the authors of the method [260, 261]. The undeniable advantages of the modified Dunn procedure include the ability to completely eliminate the deformity of the femoral component of the hip joint—which causes femoroacetabular impingement—through precise visual and fluoroscopic-guided repositioning of the femoral epiphysis [262, 263].

3.3.3 Hip arthroplasty

• Total hip arthroplasty is recommended for patients with primary or secondary hip osteoarthritis (stage III according to Kosinskaya or stages III and IV according to Kellgren and Lawrence), as well as in rare cases when other treatment options are ineffective in earlier stages of the disease [1, 12, 13, 38, 59–64, 69, 71, 79, 87, 92, 220].

GCR CLEL 5Grade of Recommendation C (Level of Evidence – 5)

Comments: Hip arthroplasty allows for rapid relief of pain syndrome, restoration of the biomechanics of the affected joint, and quick domestic and professional rehabilitation of the patient. For the long-term successful functioning of endoprostheses, an appropriate choice of implant is necessary (by design, fixation type: cemented, cementless, hybrid; bearing surface: metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic [total hip endoprosthesis with metal-on-polyethylene bearing surface***, total hip endoprosthesis with ceramic-on-polyethylene bearing surface**, total hip endoprosthesis with ceramic-on-ceramic bearing surface***]), which must be based on patient characteristics: activity level, health status, bone quality, individual anatomical changes, and the nature of the pathological process [12]. In the immediate postoperative period (prior to discharge from the hospital), control radiography of the pelvis in the anteroposterior view and the operated hip joint in two views must be performed.

In complex cases, particularly in the presence of bony ankylosis or acetabular protrusion, hip arthroplasty surgeries are exceptionally challenging due to the need to select special designs and the high demands on the practical experience of the operating surgeons. At the same time, the outcomes of such surgeries are significantly inferior to those in simpler clinical situations [264, 265].

In patients with extensive bone defects in the acetabular region, 3D modeling of such defects is advisable, along with the use of custom metal implants manufactured using modern additive technologies when specifically indicated [222].

• Hip arthroplasty in children may be recommended only in exceptional cases when there are no prospects for reconstructive organ-preserving interventions [227, 228, 229].

GCR CLEL 5Grade of Recommendation C (Level of Evidence – 5)

3.4 Other treatment

Comments: Prophylaxis of venous thrombosis should be aimed at accelerating blood flow in major veins (nonspecific prophylaxis) and correcting hemostasis (specific anticoagulant prophylaxis) [12]. Methods of nonspecific prophylaxis are aimed at preventing venous stasis; they do not increase the risk of bleeding and enhance the efficacy of pharmacological thromboprophylaxis. These include early postoperative mobilization of patients, therapeutic exercise (foot exercises, using a "foot pedal" providing passive contraction of the calf muscles) and mechanical prophylaxis (elastic compression of the lower extremities, sequential intermittent pneumatic compression, calf muscle electrical stimulation, etc.) [224].

Comments: Hip replacement is classified as a clean surgery in which the development of complications is associated with a high risk of harm to the patient's health and life. It is recommended to base the choice of drugs for perioperative antibiotic prophylaxis (PAP) on their activity against the most likely causative agents of surgical site infection for a specific surgery; cefazolin** or cefuroxime** are most commonly used [97, 223, 225].

In cases of a high risk of infectious complications (immunocompromised patient, history of infections, use of antibiotics within 2 months before surgery, etc.), it is advisable to consult a clinical pharmacologist if available in the medical institution.

• For adequate analgesia, it is preferable to use multimodal analgesia with a combination of drugs having different mechanisms of action, or monomodality if its administration is impossible [12, 96, 98, 99, 226].

GCR CLOE 5Grade of Recommendation C (Level of Evidence – 5).

Comments: Multimodal analgesia, defined as the use of various analgesics and methods targeting different mechanisms of action in the peripheral and/or central nervous system, can have additive or synergistic effects and provide more effective pain relief compared to monomodal methods. For example, clinicians may offer local anesthesia based on local anesthetics (ropivacaine**, bupivacaine**, lidocaine**, etc.) combined with opioids and NSAIDs as part of a multimodal approach to perioperative pain. Various multimodal combinations and regimens are possible for each specific situation depending on the extent of the particular surgery and individual patient characteristics [96, 98, 99, 226].

4. Medical Rehabilitation and Sanatorium-Resort Treatment

This section presents the principles and approaches to medical rehabilitation of patients with coxarthrosis who have undergone surgical treatment. Corresponding rehabilitation approaches in relevant patients receiving conservative treatment are presented in Section 3.1.1 – Non-pharmacological therapy of these clinical guidelines.

The goal of rehabilitation for patients both after organ-sparing surgeries and after hip replacement is to "eliminate impairments to facilitate patient functioning, increase their activity and social participation, and improve overall quality of life" [105].

Rehabilitation of patients is based on well-known principles: early initiation once the patient achieves an adequate level of analgesia through the multimodal use of both various pharmacological agents and non-pharmacological methods, continuity, consistency, sequence, comprehensiveness, validity, as well as an individual approach, multidisciplinary nature, and duration until positive dynamics are maintained [12, 68, 79, 106].

• Rehabilitation measures are recommended to be started in the hospital immediately after surgery and continued throughout the entire hospitalization (stage one of rehabilitation). After discharge from the hospital, if necessary, continue restorative treatment (if possible) in rehabilitation departments (stage two of rehabilitation), and finish in the conditions of day hospital medical rehabilitation departments, sanatoriums, outpatient medical organizations, or at home (stage three of rehabilitation) [12, 68, 79, 107].

GCR CLOE 5Grade of Recommendation C (Level of Evidence – 5).

Comments: The entire course of postoperative restorative treatment consists of two periods (early – 1–2 weeks and late postoperative period – up to 10–12 weeks).

The early postoperative period lasts for the first one to two weeks from the moment of surgery, during which acute postoperative reactive inflammation and healing of the surgical wound occur. Its tasks are the prevention of postoperative complications from the cardiovascular system, respiratory system, gastrointestinal tract, prevention of trophic disorders, primarily pressure ulcers, reduction of soft tissue edema, and creation of optimal anatomical and physiological conditions for the healing of tissues injured during surgery. This period corresponds to the first stage of rehabilitation and takes place in a specialized surgical department.

Basic rules of conduct in the early postoperative period following hip replacement surgery:

1. When performing most gymnastic exercises while lying in bed or sitting on a chair, the patient must keep a wedge pillow (a bolster can be used) between the legs to maintain abduction of the operated limb up to 10 - 15 degrees.

2. Patients are contraindicated from flexing the operated leg at the hip joint by more than 90 degrees.

3. Any passive or forced movements in the hip joint that cause pain are contraindicated.

4. Internal rotation and adduction are contraindicated.

5. From the first days after surgery, for the prevention of deep vein thrombophlebitis, the patient is indicated to perform active movements in the ankle joint (alternative dorsiflexion and plantarflexion) and elastic banding of the entire operated leg.

6. The patient should get up and bear weight on the operated leg only under the strict supervision of a physical therapy doctor.

7. All movements and transfers should be performed with the support of the operated limb by a physical therapist or with the assistance of the healthy leg.

The activity regimen depends on the specifics of the surgical procedure (surgical approach, stability of component fixation) and must be coordinated with the operating surgeon.

During the first week of rehabilitation (first 5 - 7 days), a sparing activity regimen is prescribed for the patient. To prevent postoperative complications, breathing exercises and proper positioning of the operated limb are performed, and exercises are prescribed to improve blood and lymph circulation as well as the functional state of the lower extremity muscles.

In the postoperative period, a pillow is placed between the patient's legs to ensure slight abduction and a neutral position of the operated limb.

From the first day after surgery, the patient is prescribed breathing exercises, active exercises for the joints of the healthy leg (hip, knee, ankle), isometric muscle exercises (gluteal, quadriceps, biceps femoris, calf muscles) of the operated limb, and passive exercises for the operated hip joint on a functional splint with a gradual increase in the flexion angle. Sessions on the splint are conducted for 15 - 30 minutes 3 - 5 times a day. In addition, the patient is taught to lift the pelvis while supporting themselves on their elbows and the foot of the operated leg.

On days 1–3 after surgery, the patient is recommended to perform the Thomas test (flexing the healthy leg at the hip and knee joints while pulling the knee toward the chest with the hands). The heel of the affected leg presses against the bed during this exercise (strengthening the hip extensors). Perform three to ten repetitions, 3 – 10 times a day.

Strengthening of the abductor and adductor muscles of the operated thigh is carried out by performing the "Hula-Hoop" exercise: legs straight, feet in dorsiflexion, with simultaneous downward pulling (lengthening) of one leg and upward pulling (shortening) of the other leg. Perform four to ten repetitions, 5 – 10 times a day.

During the same period, the operated patient is allowed to sit up in bed. From the "semi-sitting with legs lowered" position, the patient performs knee extension while holding the position for 3–5 seconds (the foot is in dorsiflexion during the exercise). Eight to twenty repetitions are performed 3–10 times a day.

During the same timeframe, the patient is mobilized into a vertical position with bilateral support (walker or high crutches) under the supervision of a physical therapy instructor

A week later, the patient is allowed to turn onto their stomach and back again, which can be done via the healthy leg. When turning via the healthy leg, a pillow must be placed between the patient's legs. When turning via the operated leg, the patient can place their hand under the operated thigh. Turns onto the stomach and back are performed 3–10 times a day.

From the "lying on the stomach" position, the patient performs five to fifteen active knee flexions and extensions 5–10 times a day, as well as three to ten active hip extensions of the operated leg 3–5 times a day. At the very beginning, this exercise should be performed in the starting position "hands under the thighs".

Lying on the stomach with knees flexed at a 90-degree angle, the patient performs crossing and uncrossing of the lower legs of the operated and healthy extremities. When performing this exercise, it is important to monitor the position of the feet. Five to ten exercises are performed 3–5 times a day.

The late postoperative period begins on the 7th–15th day after surgery and lasts for four to eight weeks (up to 10–12 weeks from the moment of surgery). The late postoperative period is conventionally divided into two stages: the early recovery period, which corresponds to the second stage of rehabilitation and is generally carried out in an inpatient setting (inpatient rehabilitation department), and the late recovery period, which corresponds to the third stage of rehabilitation and lasts from the sixth to the tenth (twelfth) week from the surgery. The main tasks of the late postoperative period are the restoration of weight-bearing function, locomotion, self-care skills, and professional and social activity.

The patient is allowed to get out of bed and is prescribed gymnastics from a standing starting position. Strengthening and stretching of the muscles (extensors, abductors, and flexors) of the operated hip are performed in the "standing with bilateral support" position.

Standing on tiptoe, the patient performs balancing with tension of the hip extensor muscles. The patient's hands are placed on a support, and feet are shoulder-width apart. The patient raises their heels while simultaneously contracting the gluteal muscles, holding the position for 3–5 seconds. Five to fifteen exercises are performed 5–10 times a day.

Strengthening of the hip extensors is performed from the following starting position: the operated leg is behind, and the "healthy" leg is semi-flexed. By lifting the heel of the operated leg, the patient contracts the extensors of the operated joint. It is recommended to hold the position for 3–5 seconds. Five to fifteen exercises are performed 5–10 times a day.

The hip abductor muscles are effectively strengthened by performing the "rumba" exercise (feet are shoulder-width apart, the patient shifts body weight from one leg to the other). This exercise simultaneously stretches the hip adductor muscles. Ten to fifteen exercises are performed 5–10 times a day. To strengthen the abductors and stretch the hip adductors, exercises using a footrest are prescribed. In the position with the "healthy leg on the footrest" (hands on a support), tension of the abductor muscles of the operated leg is performed. The tension should be held for 3–5 seconds. Five to ten exercises are performed 5–10 times a day.

In the position with the "operated leg on the footrest" (hands on a support), tension of the adductor muscles of the operated hip is performed. The tension should be held for 1–3 seconds. Three to five exercises are performed 3–5 times a day.

With weight-bearing on the footrest using the flexed operated leg at the hip joint (hands on a support), tension of the hip flexor muscles of the operated side is performed. Five to ten exercises are performed 5–10 times a day. The height of the footrest when performing this exercise is gradually increased.

In addition to static exercises in the standing position, active movements in the operated hip joint (flexion, extension, abduction) are prescribed. When performing these exercises, the patient stands on the healthy leg on a 5–8 cm high platform, hands are on a support, and the back is straight. Each exercise is performed 5–10 times, repeating up to ten times a day.

• Medical rehabilitation of patients, especially elderly and senile patients, is recommended to be initiated in the preoperative period for early mobilization in the postoperative period [12, 79].

GCR CLOE 5Grade of Recommendation C (Level of Evidence – 5).

Comments: The tasks of the preoperative period are:

• training the patient in walking without weight-bearing on the operated extremity using auxiliary support devices (crutches, cane),

• mastering activities of daily living skills (sitting down and standing up with proper body weight distribution, transferring from a bed to a chair, etc.),

• training in proper deep thoracic and diaphragmatic breathing and coughing to prevent the risks of complications from the cardiovascular, respiratory, and digestive systems; recommendations are provided on weight loss, treatment of gastropathies, and sanitation of chronic foci of infection.

Comments: The objectives of physiotherapy in the early period are the application of physical factors to achieve analgesic, anti-inflammatory, anti-edematous, resorptive, angioprotective, and reparative-regenerative effects in the target tissues of the operated extremity. Practically the entire arsenal of modern physical factors is used for this purpose.

As early as 24 hours after surgery, for rapid relief of tissue edema, prevention of inflammation, and reduction of pain severity, the patient is prescribed pulsed low-frequency electromagnetic field therapy (course of treatment 10–15 procedures; for the first 5 days, a stationary magnetic field is prescribed at a frequency of 100 Hz, field intensity of 8 mT, duration of 20 minutes; for the subsequent 5–10 days, a traveling pulsed magnetic field is prescribed at a frequency of 6.25 Hz, field intensity of 20 mT, duration of 20 minutes) immediately following ultraviolet irradiation for joint diseases (supraluminous ultraviolet therapy is used, starting with 5–6 biodoses, increasing by 1–2 biodoses every 1–2 days, with a course of 4–6 irradiations) or blue-spectrum photochromotherapy (to the suture area in the dressing room). For the same purpose, 5–6 hours after thermal procedures, it is advisable to use local cryotherapy (hypothermia) using a labile-stable technique with circular, zigzag, and rectilinear movements, pausing for 30–60 seconds in the area of greatest pain. The exposure time for a single joint is 5–10 minutes. As an additional therapeutic method for pain relief, the application of physical factors to acupuncture points (body and auricular techniques) is recommended, with a course duration of 12–15 procedures. The frequency is selected individually.

For the prevention of pneumonia and pulmonary congestion, medical chest massage or chest vibratory massage is prescribed. From the 3rd–5th day after surgery, medical massage of the lower extremity is prescribed for the contralateral limb. In elderly and debilitated individuals, immunomodulating techniques are used to enhance the body's defense mechanisms: general ultraviolet irradiation for joint diseases, EHF therapy (exposure to millimeter-range electromagnetic radiation) targeting immunocompetent structures (the middle of the sternum, the umbilical region, the projection of the adrenal glands, etc.).

In the event of a complicated postoperative course (pronounced edema, tissue infiltration, presence of neurological and vascular disorders), the rehabilitation program additionally includes various physical therapy methods, physiotherapy, and reflexology (as indicated); physiotherapy procedures may be administered twice a day.

• In some cases, it is recommended to use orthotic management as a stage of conservative treatment for patients with coxarthrosis who have contraindications to total hip arthroplasty. Following primary or revision arthroplasty, the use of orthoses is also recommended when necessary to prevent hip dislocation [134, 135, 136].

GPP CLOE 4Grade of Recommendation C (Level of Evidence – 4).

Comments: To relieve and stabilize the joint, the use of orthoses is recommended. The design must include a hinge to adjust the range of motion, located at the projection of the greater trochanter of the femur. The orthosis holds the femoral head (endoprosthesis) in the acetabulum through the femoral and pelvic components connected by a hinge. Patient compliance is enhanced by the soft-tissue base of the orthosis featuring rigid elements and straps. The use of orthoses has been proven to reduce pain and improve hip joint function, preventing dislocation of the femoral head and the endoprosthesis [134, 135, 136].

5. Prevention and Dispensary Observation

Currently, there is no recommended specific prophylaxis [12, 79].

• Following arthroplasty, it is recommended to perform radiography of the hip joints in two projections at 3 and 12 months, and subsequently once every five years [12, 79].

GCR CLOC 5Grade of Recommendations C (Level of Evidence – 5)

6. Organization of Medical Care

Indications for hospital admission to a medical organization:

1. Patients presenting with hip joint disease.

   Indications for discharging a patient from a medical organization:

2. Achieved improvement in the treatment of hip joint diseases.

Type of care

Diagnostic and therapeutic procedures for patients with primary coxarthrosis are elective.

Conditions for the provision of medical services

Diagnostic procedures at the stage of establishing a diagnosis may be carried out in an outpatient setting. Rehabilitation measures may be carried out in a day hospital setting and on an outpatient basis.

7. Additional Information

Patients who have undergone hip arthroplasty are advised against heavy physical labor and excessive sports activities involving running, jumping, lifting, and carrying heavy loads, as this may shorten the lifespan of the endoprosthesis components and lead to the need for revision arthroplasty.

Criteria for Evaluating the Quality of Medical Care

References

Appendix A1. Working Group Composition

1. L.I. Alekseeva, MD, PhD, Head of the Department of Metabolic Bone and Joint Diseases, Nasonov Research Institute of Rheumatology, Professor at the Department of Rheumatology, Russian Medical Academy of Continuous Professional Education of the Russian Ministry of Health

2. N.G. Badalov, D.Sc. in Medicine, Chief Researcher, Federal Research and Clinical Center of Medical Rehabilitation and Balneology, FMBA of Russia; Professor, Department of Restorative Medicine, Balneology, and Rehabilitation, First Moscow State Medical University (Sechenov University) of the Russian Ministry of Health

3. R.A. Bodrova, MD, PhD, Head of the Department of Rehabilitology and Sports Medicine, Russian Medical Academy of Continuous Professional Education of the Russian Ministry of Health

4. S.V. Bozhkova, MD, PhD, Head of the Scientific Department of Prevention and Treatment of Wound Infection and Department of Clinical Pharmacology, Vreden National Medical Research Center of Traumatology and Orthopedics of the Russian Ministry of Health

5. P.I. Bortulev, Ph.D. in Medicine, Head of the Department of Joint Diseases and Bone Pathology, Turner National Medical Research Center for Children's Orthopedics and Trauma of the Russian Ministry of Health

6. T.V. Buylova, MD, PhD, Director of the Institute of Rehabilitation and Human Health, Lobachevsky National Research State University of Nizhny Novgorod

7. A.O. Denisov, Ph.D. in Medicine, Scientific Secretary, Vreden National Medical Research Center of Traumatology and Orthopedics of the Russian Ministry of Health

8. Yu.A. Israelyan, Ph.D. in Medicine, Associate Professor, Department of Medical Rehabilitation, Privolzhsky Research Medical University of the Russian Ministry of Health

9. A.E. Karateev, MD, PhD, Head of the Department of Inflammatory Joint Diseases, Nasonov Research Institute of Rheumatology

10. A.Yu. Kochish, MD, PhD, Professor, Deputy Director for Research and Education, Vreden National Medical Research Center of Traumatology and Orthopedics of the Russian Ministry of Health

11. A.M. Lila, MD, PhD, Professor, Corresponding Member of the RAS, Director of Nasonov Research Institute of Rheumatology, Head of the Department of Rheumatology, Russian Medical Academy of Continuous Professional Education of the Russian Ministry of Health

12. D.V. Stafeev, Ph.D. in Medicine, Head of the Department of Traumatology and Orthopedics, Vreden National Medical Research Center of Traumatology and Orthopedics of the Russian Ministry of Health

13. R.M. Tikhilov, MD, PhD, Professor, Corresponding Member of the RAS, Director of Vreden National Medical Research Center of Traumatology and Orthopedics of the Russian Ministry of Health

14. I.I. Shubnyakov, D.Sc. in Medicine, Deputy Director for Regional Affairs, Vreden National Medical Research Center of Traumatology and Orthopedics of the Russian Ministry of Health

No conflict of interest declared.

Appendix A2. Methodology for Developing Clinical Guidelines

Target audience of these clinical guidelines

• Orthopedic trauma surgeons

• Healthcare facility administrators

• Lawyers

• Patients

Table 1. Level of Evidence (LoE) grading scale for diagnostic methods (diagnostic interventions)

Table 2. Level of Evidence (LoE) grading scale for prevention, treatment, and rehabilitation methods (preventive, therapeutic, and rehabilitative interventions)

Table 3. Grade of Recommendation (GoR) scale for prevention, diagnostic, treatment, and rehabilitation methods (preventive, diagnostic, therapeutic, and rehabilitative interventions)

Procedure for updating clinical guidelines.

The mechanism for updating clinical guidelines provides for their systematic revision at least once every three years, as well as upon the emergence of new evidence-based medicine data on the diagnosis, treatment, prevention, and rehabilitation of specific diseases, or in the presence of justified additions/comments to previously approved clinical guidelines, but no more frequently than once every 6 months.

Appendix A3. Reference Materials

These clinical guidelines were developed taking into account the following regulatory legal documents:

1. The procedure for providing medical care in the profile of "traumatology and orthopedics" was approved by Order of the Ministry of Health of the Russian Federation No. 901n of November 12, 2012.

2. Order on Approval of Quality Assessment Criteria for Medical Care No. 203n of May 10, 2017

Appendix B. Physician Action Algorithms

Appendix C. Patient Information

A patient suffering from coxarthrosis must follow the physician's prescriptions, adhere to the core principles of postoperative rehabilitation, and follow recommendations in the long-term period after surgical treatment:

• walk with crutch support for 6-12 weeks;

• on days 12-14, return to the local outpatient clinic to have the sutures removed;

• after suture removal, undergo a rehabilitation course (exercise therapy, massage, exercise machines, swimming pool, etc.);

• perform follow-up radiography of the joint 3 months after surgery to determine the further weight-bearing regimen for the limb;

• subsequently avoid heavy impact and static loads on the joint;

• undergo courses of conservative rehabilitation treatment.

Total hip arthroplasty is a reconstructive surgical procedure that involves replacing a damaged joint with an artificial one to reduce pain intensity, restore hip joint mobility, and recover lower limb weight-bearing capacity.

The advantages of total hip arthroplasty over other types of surgical treatment include rapid patient mobilization, early loading of the operated limb, restoration of joint movement, and positive predictable long-term outcomes. The functional lifespan of modern endoprosthesis models is 90–95% at 15 years, over 80–90% at 20 years, and 75–80% at 25 years postoperatively.

Unfortunately, many patients with advanced stages of coxarthrosis unnecessarily delay this type of treatment due to fear of surgery and lack of information. They have to endure daily pain, limit their active lives, and experience emotional distress. Joint replacement surgery is a realistic opportunity to restore lost limb function and stop feeling constant joint pain.

Total hip arthroplasty is performed under spinal or general anesthesia (endotracheal anesthesia). Spinal anesthesia is optimal and easily tolerated. It is used in somatically healthy patients and those with mild to moderate comorbid conditions. If there are contraindications to spinal anesthesia, most commonly in patients with severe comorbidities, general anesthesia (endotracheal anesthesia) is used. Modern medications used during anesthesia minimize the risk of complications and smooth out discomfort during surgery and emergence from anesthesia. The duration of the surgery ranges from 1 to 2 hours (sometimes longer) and is determined by the severity of the pathological changes in the hip joint.

Postoperative period. After surgery, you will be taken to the intensive care unit, where you will stay until the evening of the same day or the morning of the next day. There, intensivists and nurses will monitor your condition and provide necessary medical care: administration of painkillers, blood transfusions and blood substitutes if needed, and so on. In the presence of pronounced postoperative anemia, restoring blood loss without blood component transfusion is impossible!

During surgery, surgeons restore movement in the hip joint, but postoperative pain may limit flexion and extension. Your main task in the postoperative period is to control pain by taking prescribed medications on time.

On the first day after surgery, bed rest is usually recommended. Movements of the operated limb are permitted in full range. If your general condition is satisfactory, you can sit up in bed, dangle your legs, and get up with additional crutch support. Before bedtime and as needed, you will be given painkillers and sedatives (sleeping pills). You will be examined by an exercise therapy doctor. Based on the specifics of the surgery, they will select an individual postoperative rehabilitation program. Every exercise prescribed by the doctor will be taught to you by an exercise therapy instructor. They will work with you once a day throughout the entire postoperative period; the rest of the time during the day, you must exercise independently. Walking around the ward and department requires the use of crutches.

Rehabilitation exercises

Follow these simple rules: movements in the operated joint must be smooth and uniform, and the range of motion should increase gradually.

1. Exercises to strengthen the lower limb muscles.

1.1. Contract your thigh muscles by straightening the lower limb at the knee joint. Hold it in this position for 5–10 seconds. Repeat this exercise 10 times, rest, and repeat until thigh muscle fatigue occurs.

1.2. Straight leg raise. Lying on the bed, contract your thigh muscles, fully straighten the lower limb, and lift the leg a few centimeters above the bed. Hold it in this position for 5–10 seconds. Lower it carefully. Repeat this exercise 10 times, rest, and repeat until thigh muscle fatigue occurs. This exercise can be performed lying down or sitting.

1.3. Rhythmically raise and lower your foot by contracting your calf muscles. Perform this exercise for 2–3 minutes 2–3 times an hour.

2. Exercise for lower limb extension.

Roll up a towel and place it under your heel so that it does not touch the bed. Tightening your thigh muscles, try to completely straighten your lower leg and touch the bed with the back surface of your knee joint. Repeat this exercise until your thigh muscles feel fatigued.

3. Walking. Walking on a flat surface and stairs is an exercise to build strength and endurance. Soon after surgery, you will start walking around the ward. Early activity will promote your rapid recovery and help restore muscle strength and range of motion in the knee joint.

3.1. Using a walker. A walker helps maintain balance. Initially, when walking, try to put as little of your body weight on the operated lower limb as possible.

Rules for walking with a walker

Step 1. Lift and place the walker 10–15 cm in front of you with both hands. Make sure all four legs of the walker are firmly supported on the floor.

Stage 2. Lean on the walker and shift most of your body weight onto it.

Stage 3. Step forward with the operated lower limb (inside the walker). Make sure that your foot does not catch on the leg of the walker.

Stage 4. Grasping the walker firmly with both hands, take a step forward (inside the walker) with the unoperated lower limb.

4.2. Using crutches. Once the lower limb muscles are sufficiently strengthened, crutches can be used instead of a walker.

4.2.1. Walking on a flat surface with crutches:

Stage 1. Grasp the handles of the crutches firmly. The main weight must be supported by your hands, not your armpits.

Stage 2. Move the operated leg and both crutches forward simultaneously.

Stage 3. Move the unoperated leg forward.

4.2.2. Going down stairs with crutches:

Stage 1. Place the crutches and the operated leg on the lower step.

Stage 2. Maintaining balance with the crutches, lower the unoperated leg onto the step.

4.2.3. Going up stairs with crutches:

Stage 1. Place the crutches vertically on the floor and lean on them securely.

Stage 2. Lift the unoperated leg and place it on the step.

Stage 3. Leaning forward on the crutches, step up to the step where the unoperated leg is standing.

Body weight should be distributed between the crutches and the unoperated leg. Always start moving upward with the healthy leg, and downward with the operated leg. Remember: up with the good, down with the bad.

Walking with a single crutch. When you can walk and stand for more than 10 minutes (usually achieved 2–4 weeks after surgery), it is advisable to transition to walking with a cane or a single crutch. Always hold the cane in the hand opposite to the operated leg. When going up or down stairs, always use the handrail for additional support. Always start moving upward with the healthy leg, and downward with the operated leg. Remember: up with the good, down with the bad.

After discharge from the hospital:

Therapeutic physical training (TPT) Goal: strengthening the muscles of the thigh and lower leg of the operated limb; increasing the range of motion in the operated joint, preventing the development of joint stiffness and contractures; weight loss; reducing pain syndrome in the operated knee joint.

Independently, at home, continue to perform daily the set of exercises taught to you by the physical therapy doctor. In an outpatient clinic, sanatorium, or rehabilitation center, where modern rehabilitation methods (mechanotherapy, massage and physiotherapy, orthotics) will be added to the standard set of exercises.

If there is a risk of hip dislocation after arthroplasty surgery (primary, revision), the use of orthoses is recommended during TPT classes, as well as during daily activities from the first days after surgery.

The first six weeks after surgery

The patient is advised not to sit on low chairs. It is best to sit on a firm, straight-backed chair with a high seat and armrests that can be used when the patient stands up. A small pillow can be used to raise the chair. The patient should sit in a so-called "sliding" position, leaning back slightly and extending the operated leg forward. When getting up from a chair, you can extend the operated leg forward without leaning your torso forward. While sitting, it is advisable to keep your legs apart at a distance of 7-15 cm, extending the operated leg slightly forward and making sure that the toe of the operated leg does not turn inward or outward.

During the day, the patient should sit for half an hour no more than three times a day.

The patient is recommended to sleep on their back. It is not advisable to sleep on the healthy side (adduction and internal rotation of the operated leg may occur during sleep). Every morning and evening, it is recommended to lie on your stomach or back on a flat surface for 20 minutes.

In a car, the patient should sit in the front seat, having previously placed two pillows on the seat and moved it as far away from the dashboard as possible. When sitting down, the patient should lean back as far as possible against the backrest, and then, relying on the healthy leg, slowly bring the operated leg into the cabin, keeping it in front of them. While riding, the patient should remember to always keep their legs apart, and that sliding the operated leg into the car is better than bending the leg at the hip joint.

Do not cross your legs while lying or sitting. Do not bend the leg at the hip joint more than 90 degrees. The basic rule for patients who have undergone arthroplasty is as follows: avoid simultaneous flexion, adduction, and internal rotation in the operated hip joint. Guided by this rule, you cannot squat, bend down, or hang over the edge of the bed to pick up things from the floor; you cannot reach for lower drawers or cabinets, bend over during personal hygiene, put on (or take off) shoes in a position of maximum flexion, adduction, and internal rotation. In addition, there are a number of other positions and postures in which the risk of instability in the operated hip joint is highest, namely:

getting up from a chair or sitting down from a position where the operated leg is adducted and internally rotated,

in a sitting position (knees together, feet apart), leaning the torso forward or turning it toward the operated joint.

When bending down to the floor, you should place the operated leg backward. When dressing or picking up things from the floor, you can use a gripping device.

The patient should immediately consult a doctor if the following symptoms appear: redness, swelling, or an increase in skin temperature in the area of the postoperative suture, discharge from the postoperative suture, severe pain in the hip joint, "clicking" in the joint, shortening of the limb accompanied by external rotation of the foot, loss of control over limb movement.

Do not take a bath in a lying position, a shower is preferred. While washing, it is recommended to use a special sitting bench. Rubber mats should be placed in the tub itself to prevent the feet from slipping. The wash sponge can be attached to a stick to avoid bending the body while washing the legs.

At home, small rugs should be removed, loose ends of carpets in rooms should be secured, and items should be placed at the height of the hip and shoulder joints to avoid unnecessary bending.

You should not wear high heels, lift heavy objects, do gardening, or drive a car.

From the seventh week after surgery

You can sleep on the operated side (specific timing depends on how comfortable it is for the patient). In 3-4 months, you can sleep on the healthy side.

You should periodically continue to lie on your stomach or back on a flat surface.

Do not force movements in the hip joint using passive movements.

In 2-3 months after surgery, driving a car is allowed. In 2-3 months, you can abandon the elevated seat and the pillow between your knees. After 3 months, the patient is allowed to bend over, and can stop sitting in the "sliding" position.

Further throughout life

You can engage in sports such as swimming, cycling, golf, bowling.

Contraindicated: running, tennis, rugby, skiing, ice skating, yoga, or other physical exercises that require quick stops, starts, or rotations.

If a local infectious process appears anywhere in the body, you should immediately consult a doctor and carry out a course of treatment as soon as possible to prevent the infection from spreading to the hip joint. A preventive course of antibacterial therapy should also be carried out after tooth extraction. You should eat foods rich in proteins, iron, calcium, and vitamin C. For the prevention of bone tissue resorption in the prosthesis area, courses of low-frequency pulsed magnetotherapy are recommended [132, 133]

In conclusion, I would like to emphasize that without your active participation, it is impossible to achieve the result of the surgery that would satisfy both you and your attending physician. Remember, while you are in the hospital, the department staff will create conditions for your comfortable recovery treatment and provide the necessary assistance. We urge you to make maximum efforts in the postoperative period to restore the range of motion in the hip joint and the normal function of the lower limb.

Appendix G. Assessment Scales, Questionnaires, and Other Evaluation Tools

Appendix G1 Classifications by N.S. Kosinskaya, J. Kellgren et J. Lawrence, D. Tonnis.

Name in Russian: N.S. Kosinskaya, J. Kellgren et J. Lawrence, D. Tonnis scales.

Original title (if applicable):

Source (official developer website, publication with

validation):

Type (underline):

• rating scale

• index

• questionnaire

• other__________________________________________________________

Purpose: assessment of the functional capabilities of the hip joint

Assessment tool, content:

Key (Interpretation): The key matches the content