Patellar fractures: Clinical Guidelines

List of Abbreviations

VKA – vitamin K antagonists

ACT – activated clotting time

EFA – external fixation apparatus

AO – Association for Osteosynthesis

TIB – tibia

VTE – venous thromboembolism

RTA – road traffic accident

BMI – body mass index

Knee – knee joint

CT – computed tomography

HDL – high-density lipoproteins

LDL – low-density lipoproteins

PT – physical therapy

MDRT – multidisciplinary rehabilitation team

Ministry of Health of the Russian Federation – Ministry of Health of the Russian Federation

MMA – multimodal analgesia

MRI – magnetic resonance imaging

LMWH – low-molecular-weight heparin from the B01AB heparin group

NSAIDs – nonsteroidal anti-inflammatory drugs from the M01A Non-steroidal anti-inflammatory and antirheumatic products group

UFH – unfractionated heparin (INN heparin sodium**)

PF – patellar fracture

SWD – surgical wound debridement

РКИ – randomized controlled trial

SCT – spiral computed tomography

TIA – transient ischemic attack

RF – risk factors

PRM – physical and rehabilitation medicine

FS – functional status

TENS – transcutaneous electrical nerve stimulation

Surgical antibiotic prophylaxis

LCP – locking compression plate

MIPO – minimally invasive plate osteosynthesis

ORIF – open reduction internal fixation – open reduction with internal fixation

Terms and Definitions

Absolute stability – absence of micromotion at the fracture site, provided there is anatomical reduction and interfragmentary bone compression after fixation with hardware.

Anticoagulants – chemical substances and medicinal products that inhibit the activity of coagulation hemostasis (the blood clotting system) and prevent blood clot formation, belonging to the ATC group B01A "Antithrombotic agents".

Allograft – a bone tissue fragment from another human (donor), typically cadaveric, that has undergone preservation.

Antibacterial drug – a medicinal product from group J01 Antibacterials for systemic use.

External fixation device (EFD) – an orthopedic device containing an implant (a transosseous or extracorporeal element protruding through the skin, reaching the bone or inserted into it) and an external (non-implantable) support connecting bone fragments via transosseous elements in the treatment of fractures, pseudoarthrosis, or gradual lengthening (deformity correction) of a segment.

Autograft – a fragment of the patient's own bone harvested from a donor site for transplantation to fill a bone tissue deficit (bone defect).

Beta-lactam antibiotics – are a group of antibacterial drugs sharing a common structural element — the beta-lactam ring. They inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins, leading to lysis and death of the microbial cell. According to the Anatomical Therapeutic Chemical classification, beta-lactam antibiotics include the following main groups: Beta-lactam antibacterials, penicillins (J01C) and Other beta-lactam antibacterials (J01D), of which the most clinically significant are first-generation (J01DB), second-generation (J01DC), third-generation (J01DD), fourth-generation (J01DE) cephalosporins, other cephalosporins and penems (J01DI), carbapenems (J01DH), and monobactams (J01DF).

Internal fixation device – an orthopedic implant implanted beneath the patient's skin that connects bone fragments in the treatment of fractures, deformities, or nonunions.

Impression – the process of articular surface fracture formation resulting from excessive pressure of the articulating bone exceeding the strength of spongy bone tissue, as well as the resulting impression fracture.

Fracture union – mutual connection of fragments by living bone tissue as a result of the successful completion of reparative regeneration.

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

Bone fragment – a portion of bone separated as a result of trauma, surgery, or a destructive process.

Migration of fixation elements – loss of the optimal position of fixation elements due to bone resorption around them, occurring when allowable cyclic loads or their number are exceeded, or due to errors in the surgical technique of implanting the element into the bone (within the context of this topic).

Load – mechanical force applied to a limb, bone, and fixation system during treatment, typically recurring with constant periodicity (cyclically).

Delayed union / Nonunion – changes in the reparative regeneration of bone tissue leading to a decrease in its rate, cessation, or formation of a callus insufficient to perform mechanical function.

Nonsteroidal anti-inflammatory drugs – nonsteroidal anti-inflammatory drugs from the group "Anti-inflammatory and antirheumatic products, non-steroids" (M01A).

Post-traumatic deformity – fracture consolidation with disruption of spatial relationships between fragments, including axial and rotational alignment.

Fixation stability – resistance of the system to external loads, allowing it to maintain the constancy of the mutual orientation of fragments and the optimal distance between them.

Fixation – a state in which relative or complete immobilization of fragments is achieved.

1. Brief information on the disease or condition

1.1 Definition of the disease or condition

Patella – the largest sesamoid bone in the human body, located within the thickness of the distal tendon of the quadriceps femoris muscle and participating in the formation of the knee joint. Patellar fractures (PF) are a disruption of the integrity of the bone structure of the patella; the fracture line or lines may extend to the articular surface [1, 2].

In the anatomy of the patella, the base of the patella facing upwards and the apex of the patella directed downwards are distinguished. The posterior surface of the patella is covered with articular cartilage and forms the patellofemoral articulation (patellofemoral joint) with the patellar surface of the femur. The anterior surface of the patella is smooth and easily palpable through the skin [3].

The joint capsule of the knee joint attaches to the patella along the edge of the articular surface. The tendon of the quadriceps femoris muscle attaches to the base of the patella, with fibers also weaving into the joint capsule. The internal and external tendon bundles run from the patella to the epicondyles of the femur and the condyles of the tibia and are called the medial and lateral patellar retinacula. The dense section of the knee joint capsule below the patella is reinforced by fibers of the quadriceps femoris tendon and is called the patellar ligament [3].

The patella is an important part of the extensor mechanism, acting as a fulcrum for the quadriceps femoris tendon. As a result, two levers are formed: the quadriceps tendon and the patellar ligament. This arrangement of the patella determines its high functional load. Forces transmitted through the patella during knee extension can reach seven times body weight. Certain activities, such as stair climbing and squatting, can generate tension on the anterior surface of the patella approaching the fracture threshold. Therefore, high demands are placed on patellar osteosynthesis in terms of load-bearing stability [1].

Due to its structural features and location, the patella increases the efficiency of quadriceps femoris contraction by 30% during knee extension [4, 5]. The increased lever arm of the extensor mechanism, due to the patella acting as a fulcrum, adds 60% of the force required for full knee extension, which is most pronounced in the final 15° of extension [1].

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

Due to the anatomical position of the patella, the predominant mechanism of injury is a direct blow. The most frequent causes of PF are falls from standing height (44.3% of cases) and motor vehicle accidents (MVAs) (33.0% of cases). Among men, a high-energy mechanism—MVAs (44.1% of cases)—prevails, whereas among women, a low-energy mechanism—falls onto the knee joint (68.3% of cases)—predominates [6]. About half of PFs are characterized by the absence of fragment displacement, with the extensor mechanism remaining intact [1].

Since the posterior surface of the patella forms the patellofemoral articulation with the distal femur and constitutes three-quarters of an articular surface, patellar fractures are mostly intra-articular, requiring anatomical reduction of fragments to restore articular surface congruence [6].

Osteochondral lesions are injuries to the cartilage and underlying subchondral bone, frequently encountered in children and adolescents. They typically result from low-energy trauma or sports activities [10]. Osteochondral lesions are most commonly observed following acute patellar dislocation. They manifest as damage to the medial facet of the patella and/or the lateral femoral condyle [11, 12]. The mechanism of dislocation may involve either direct impact on the patella, causing a traumatic dislocation, or the more common indirect mechanism—external rotation of the tibia combined with semi-flexion of the knee joint [13, 14]. The incidence of osteochondral fractures in acute patellar dislocation ranges from 39% to 71% [15, 16]. The young population is more susceptible to such injuries due to a combination of ligamentous hypermobility (increased shear risk during rotational movements) and a sharp change in mechanical properties at the transition zone from articular cartilage to subchondral bone [14]. These lesions are easily overlooked, which, in the absence of timely treatment, can lead to the premature development of degenerative joint disease [10, 17].

1.3 Epidemiology of the Disease or Condition

The incidence of patellar fractures (PF) ranges from 0.5% to 1.5% of all musculoskeletal injuries [7, 8]. Comminuted PFs account for 55% of all PFs [9]. According to a retrospective study by S. Byun et al. (2019), this injury occurs predominantly in men (in 61.9% of cases). The average age of patients is 51.3 years: 47.6 years for men and 57.4 years for women. However, the authors note that in recent years there has been a trend towards an increase in the average age of victims, as well as the proportion of female patients with patellar fractures [6].

In the pediatric population, patellar fractures account for approximately 1% of all fractures and are mainly associated with primary patellar dislocation or sports injuries with a direct trauma mechanism [161, 162].

1.4 Features of Coding the Disease or Condition

S82.0 – Fracture of patella

1.5 Classification of the disease or condition

In clinical practice, PFs are conventionally divided into non-displaced and displaced fractures. Significant displacement affecting treatment choice is generally considered to be fragment separation of more than 3 mm or displacement of articular surface fragments of the patella by more than 2 mm [19]. Patellar fractures can be divided into extra-articular and intra-articular. Most often, PFs are intra-articular due to anatomical features [6]. One of the simplest classifications is dividing PFs by character (type):

• transverse,

• vertical,

• comminuted,

• marginal,

• osteochondral [18].

From the perspective of selecting surgical treatment tactics, the AO/ASIF (Association for Osteosynthesis) classification is currently the most widely used. This classification also simplifies data recording and statistical processing in scientific research. According to the AO universal fracture classification, PF corresponds to code 34 [2]. Fractures of this localization are subdivided into three types based on the degree of involvement of the articular surface of the patella:

34-A – extra-articular fracture:

34-A1 – extra-articular avulsion fracture;

34-B – partial intra-articular fracture in the sagittal plane:

34-B1 – partial intra-articular fracture in the sagittal plane, lateral location;

34-B2 – partial intra-articular fracture in the sagittal plane, medial location;

34-C – complete intra-articular fracture in the horizontal plane:

34-C1 – complete intra-articular fracture in the horizontal plane, simple;

34-C2 – complete intra-articular horizontal fracture with a wedge-shaped fragment;

34-C3 – complete intra-articular horizontal fracture, comminuted [2].

Comments. The AO classification is based on the classification proposed by M. Speck and P. Regazzoni in 1994. According to it, patellar fractures can be divided into 3 types (A, B, C), with each type comprising three subgroups [21]. Earlier studies present patellar fracture classifications divided into 7 types [22]. However, it should be noted that the modern AO classification has gained the most popularity.

For open patellar fractures, the classification by R.B. Gustilo and J.T. Anderson (1976) [23], modified by R.B. Gustilo, R.M. Mendoza, and D.N. Williams (1984) [24], is used:

Type I – open fracture, the wound is minimally contaminated, wound size is less than 1 cm;

Type II – open fracture, the wound is greater than 1 cm and less than 10 cm in length without significant soft tissue damage, flaps, or skin detachment;

Type IIIA – open fracture, soft tissues cover the fragments, no periosteal stripping in the presence of extensive soft tissue damage or flaps, or in high-energy trauma regardless of wound size;

Type IIIB – open fracture with an extensive soft tissue defect, periosteal stripping, and a comminuted fracture pattern, often with significant microbial contamination of the wound;

Type IIIC: open fracture complicated by major vascular injury requiring surgical reconstruction, regardless of the extent of soft tissue damage.

For pediatric patients, the classification by Dai et al. has been proposed; the authors distinguish transverse, avulsion, and comminuted fractures in their classification. Avulsion fractures are characteristic of patients with incomplete skeletal growth. In avulsion fractures, there is a detachment of the cartilaginous model, which often includes the articular surface along with a small bone fragment [161]. Furthermore, literature shows that avulsion fractures can affect any part of the patella [163].

1.6 Clinical presentation of the disease or condition

Clinical presentation of patellar fractures is characterized by severe pain in the knee joint area, joint dysfunction, smoothing of its contours and edema, and tenderness on palpation. In cases of significant displacement of bone fragments, soft tissue depression in the fracture zone may be observed. Axial load on the injured limb may not cause severe pain, but an attempt to flex the knee joint is accompanied by a sharp increase in pain. In transverse or comminuted patellar fractures, active extension of the lower leg may be impossible due to disruption of the extensor mechanism [25, 26, 27, 28].

Complaints: pain in the knee joint area, restricted range of motion in the knee joint, sharp pain upon flexion, and inability to extend the knee joint. Patients may complain of an increased volume of the knee joint, its deformation, and a feeling of instability of the injured lower limb in the knee joint area. In cases of open fractures, patients complain of pain in the wound area and bleeding [25, 26, 27, 28].

History: history of trauma; the patient describes a characteristic mechanism of injury.

The classic mechanism of injury is a direct blow to the patella or a fall onto a flexed knee joint. Less commonly, patellar fractures occur as a result of excessive contraction of the quadriceps femoris muscle [25, 26, 27, 28].

Objective examination: edema in the knee joint area, limitation of active and passive movements due to severe pain syndrome, visually detectable deformation of the knee joint, tenderness on palpation in the anterior knee joint area, crepitus of bone fragments, pathological mobility in the patella area, patellar tapotement (ballotement), and soft tissue depression in the patellar fracture area palpable upon fragment displacement. In open fractures, wounds are present in the knee joint area. A sign of an open patellar fracture is the presence of bone fragments in the wound, as well as the outflow of synovial fluid from the wound, given the presence of other signs of a patellar fracture [25, 26, 27, 28].

For pediatric patients, no conclusive data have been identified regarding differences in the clinical presentation of patellar fractures [164, 165].

2. Diagnostics, medical indications and contraindications for diagnostic methods

Criteria for establishing the diagnosis/condition:

• anamnestic data: indication of a characteristic mechanism of lower limb injury (falling on the knee joint, a blow to the knee joint area, traffic accident, etc.);

• physical examination data: impaired function of the injured segment, deformation, local edema, and tenderness of the injury area (pain increases with movements in the knee joint), presence of pathological mobility and/or fragment crepitus;

• instrumental examination data: radiographic signs of fracture based on patellar radiography or knee joint radiography in 2 projections. For patellar fractures with suspected intra-articular involvement, additional computed tomography (CT) of the knee joint is recommended as prescribed by the on-duty or attending trauma surgeon/orthopedic surgeon or surgeon to clarify the nature of the fracture and determine the degree of fragment displacement.

2.1 Complaints and Anamnesis

In most cases, patients present with complaints described in section 1.6 "Clinical Presentation".

• All patients with suspected patellar fractures are recommended a thorough collection of history and complaints regarding bone pathology for diagnostic purposes [1, 25-28].

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

2.2 Physical Examination

Physical examination findings are described in section 1.6 "Clinical Presentation".

• Patients with suspected bone fracture are recommended an initial consultation (examination, interview) by an orthopedic trauma surgeon for diagnostic purposes [1, 25-29, 191].

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

Comments: the medical history must record the results of:

- somatic status assessment;

- visual and palpation assessment of local status;

- blood pressure measurement (measurement of blood pressure in peripheral arteries);

- body temperature measurement (general thermometry);

-  assessment of the risk of venous thromboembolic complications (Appendix G1).

• Patients with suspected bone fracture are recommended an assessment of innervation and blood circulation status in the distal lower extremity to rule out neurovascular bundle injury at the fracture level or compartment syndrome [1, 25-28].

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

• Patients with suspected bone fracture are recommended an assessment of soft tissue status and the degree of edema to rule out hematomas and open fractures [1, 25-28].

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

• When deciding on surgical treatment of a bone fracture in adult patients, it is recommended to take a history and ascertain complaints related to bone system pathology to identify risk factors and cardiovascular diseases [30, 31].

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

Comment: cardiovascular disease risk factors include: arterial hypertension, smoking, dyslipidemia (elevated total cholesterol >4.9 mmol/L and/or LDL cholesterol >3 mmol/L and/or HDL cholesterol in men <1.0 mmol/L, in women <1.2 mmol/L, and/or triglycerides >1.7 mmol/L), diabetes mellitus, and a family history of premature cardiovascular disease (<55 years for men and <65 years for women) [30]. Established cardiovascular disease is defined as: coronary artery disease, cerebrovascular disease, peripheral artery disease, chronic heart failure, pulmonary hypertension, valvular heart disease, and cardiomyopathies [31, 32].

• All adult patients referred for elective surgical treatment of a bone fracture are recommended an assessment of the risk of perioperative cardiovascular complications, taking into account the type of planned bone fracture surgery, regardless of the presence of comorbid pathology, for the purpose of complication prevention [29, 33].

GPR CLOC 4Grade of Recommendation C (Level of Evidence – 4).

Comments: when performing surgical treatment for emergency (less than 6 hours) and urgent (6–24 hours) indications, perioperative risk assessment is not performed.

Minor orthopedic surgeries are associated with a low risk of cardiovascular complications (30-day risk of myocardial infarction or cardiovascular death after surgery is less than 1%). Major orthopedic surgeries are associated with an intermediate (moderate) risk of cardiovascular complications (30-day risk of myocardial infarction or cardiovascular death after surgery is 1–5%) [34].

• To assess the risk of perioperative cardiovascular complications in adult patients, it is recommended to use a special algorithm (Appendix B2) [34].

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

• Elective surgical treatment of a bone fracture aimed at creating conditions for bone healing is recommended without additional workup in adult patients whose cardiovascular risk is assessed as low. In patients with intermediate or high perioperative risk of cardiovascular complications, it is recommended to assess the patient's functional status for the purpose of complication prevention [34, 36].

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

2.3 Laboratory Diagnostics

• All patients diagnosed with a bone fracture, if surgical treatment is planned, are recommended to undergo the following laboratory tests for diagnostic purposes [25, 37, 38, 39, 40, 202, 203, 207, 208]:

  - complete blood count;

  - urinalysis;

  - general clinical biochemical blood test: study of total bilirubin level in blood, blood urea level test, total blood protein level test, blood creatinine level test, blood glucose level test, determination of alanine aminotransferase activity in blood, determination of aspartate aminotransferase activity in blood;

  - determination of main ABO blood groups and D antigen of the Rhesus system (Rh factor);

  - coagulogram (exploratory hemostasis evaluation) with determination of the international normalized ratio (INR).

LEL 5Grade of Recommendation C (Level of Evidence – 5).

• When deciding on surgical treatment of patellar fractures in adult patients, it is recommended to test the level of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in the blood in cases of intermediate or high risk of cardiovascular complications and low functional status to determine further management (see Appendix B2) [30, 34, 40, 41].

QOE 2Level of Evidence A (reliability of evidence level – 2).

2.4 Instrumental Diagnostics

• In patients with suspected patellar fracture, it is recommended to perform radiography of the patella or radiography of the knee joint including the lower third of the femur and upper third of the tibia (lower extremity radiography) in two projections for diagnostic purposes [1, 18, 25-28, 42].

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

Comments. Knee radiographs in two projections are a mandatory examination as they allow visualization of the patella and surrounding bone structures [18, 42]. If a symmetrical high or low position of the patella is present compared to the contralateral limb, patella alta or baja is likely. Conversely, an asymmetric position of the patella suggests a rupture of the quadriceps tendon or patellar ligament, and this condition must be ruled out [18]. Diagnosis of patellar fractures with a fracture line located in the sagittal plane may be difficult when performing radiography in two standard projections. An axial view may be used to visualize this type of fracture, although knee flexion required for adequate axial visualization of the patella may cause significant discomfort to the patient [42].

Children have specific radiological features that must be taken into account at the diagnostic stage. The patella begins to ossify at the age of 3-5 years and is often represented by multiple ossification centers. In some cases, incomplete fusion of the superolateral ossification center is observed—a condition known as patella bipartita. This condition is often mistakenly interpreted as a patellar fracture [166]. Also, pediatric patients with Nail-patella syndrome exhibit a reduction in patellar size and delayed ossification, which can also create difficulties in diagnosing knee joint injuries in these patients [167]. Case series have been described in patients with the consequences of knee injuries manifested as the formation of ossifications within the proper patellar ligament. These changes can be similar in clinical presentation to avulsion fractures of the patella, which must be considered in differential diagnosis [168].

• In all adult patients with patellar fractures, it is recommended to perform MSCT of the knee joint (computed tomography of the lower extremity, computed tomography of the joint) when a comminuted and/or intra-articular fracture is suspected to clarify the diagnosis [1, 18, 42, 43].

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

Comments. MSCT provides additional information on the nature of the fracture, the degree of fragment displacement, and the involvement of adjacent bone structures [1, 18, 42, 43].

• In all adult patients with patellar fractures, if damage to the capsular-ligamentous apparatus of the knee joint or osteochondral patellar fracture is suspected, it is recommended to perform MRI of the knee joint (magnetic resonance imaging of soft tissues, magnetic resonance imaging of bone tissue (one region), magnetic resonance imaging of joints (one joint)) to clarify the diagnosis [18, 20].

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

• Echocardiography for the prevention of complications may be considered before planned surgical treatment of patellar fractures in adult patients with low functional status, elevated NT-proBNP levels, left ventricular systolic dysfunction, cardiomyopathies, heart defects, newly detected heart murmurs, and suspected cardiovascular disease [34, 48, 49].

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

2.5 Other Procedures

• When treating patients with patellar fractures, it is recommended to consider the following indications for consultations with relevant specialists in clinical practice to rule out life- or health-threatening conditions:

  - initial neurosurgeon's appointment (examination, consultation): in case of nerve injury or suspected nerve injury and concomitant head injury;

  - initial surgeon's appointment (examination, consultation): in case of suspected or objectively diagnosed concomitant abdominal and/or chest injury; pediatric surgeon's appointment in case of suspected or objectively diagnosed concomitant abdominal and/or chest injury in pediatric patients;

  - initial neurologist's appointment (examination, consultation): in case of nerve injury or suspected nerve injury and concomitant head injury;

  - initial cardiovascular surgeon's appointment (examination, consultation): in case of concomitant vascular injury or suspected vascular injury;

  - initial general practitioner's appointment (examination, consultation) or initial pediatrician's appointment (examination, consultation): in the presence of comorbid therapeutic conditions (according to anamnesis) [25, 26, 50].

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

• If acute or unstable clinical conditions are detected (assessed according to Appendix G2. Revised Cardiac Risk Index rRCRI), in order to improve cardiac status and stabilize the patient's condition, it is recommended to postpone elective surgical treatment of the patellar fracture and transfer the patient to a regional vascular center or specialized cardiological department [34].

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

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

3.1 Conservative Treatment

• For patients with patellar fractures upon admission to the hospital, it is recommended to provide the following minimum scope of care in the emergency department to stabilize the general condition and prevent complications:

  - ensuring thermal comfort for the patient;

  - adequate pain management;

  - immobilization of the injured lower extremity;

  - correction of volemic and electrolyte disorders [25, 26, 38, 50].

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

• In patients with patellar fractures, it is recommended to apply a plaster cast for bone fractures or an immobilization bandage for bone fractures as part of conservative treatment in the following cases to achieve bone union:

  - stable patellar fracture without displacement;

  - stable patellar fracture with fragment displacement of less than 2–3 mm;

  - in the presence of comorbid pathology that is a contraindication to surgical treatment;

  - upon the patient's voluntary refusal of surgery [1, 25-28, 52, 169].

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

Comments. The criterion for patellar fracture stability is the absence of fragment displacement on control radiographs when flexing the knee joint up to 60°. According to studies, even comminuted patellar fractures can be managed conservatively if the fracture meets stability criteria [51, 52].

Immobilization (application of a plaster cast for bone fractures) of the knee joint as part of conservative treatment inevitably leads to an extended recovery period due to the development of contracture. To mitigate the negative effects of immobilization, it is necessary to create conditions for early functional movements in the knee joint. This can be achieved, in particular, by using a specialized orthosis that restricts knee flexion while allowing a gradual increase in the range of allowed motion. However, despite attempts to restore knee function during the fixation period in conservative treatment, knee contracture is frequently noted among complications due to fracture nonunion and/or prolonged immobilization. Furthermore, the persistence of even a minor residual displacement of bone fragments in the conservative treatment of patients with patellar fractures invariably leads to knee stiffness associated with incongruity of the articular surfaces of the patellofemoral joint [51].

3.2 Surgical Treatment

The majority of patellar fractures are intra-articular. Therefore, the goal of surgical treatment is to restore the anatomy of the articular surface and achieve stable fixation of bone fragments, thereby ensuring early rehabilitation. Additionally, osteosynthesis for patellar fractures without fragment displacement is performed according to social indications when it is necessary to shorten the rehabilitation period or avoid the need for prolonged immobilization [6].

• Patients with patellar fractures are recommended osteosynthesis with Kirschner wires and a tension band wire or cannulated screws and a tension band wire to fix the patellar fragments and create conditions for bone healing [1, 18, 55, 56, 58, 65, 66].

Adults - Level of recommendation A (evidence level – 2).

Children — Strength of recommendation C (Evidence level — 5).

Comments: when performing osteosynthesis of the patella using Kirschner wires and a tension band wire or cannulated screws and a tension band wire, the following implants are used: non-absorbable non-sterile orthopedic bone screw***, non-absorbable sterile orthopedic bone screw***, dynamic bone screw***, absorbable orthopedic bone screw***, cannulated compression bone screw, orthopedic bone wires and pins***.

The method of bone fragment fixation in patellar fractures using a tension band is traditional and involves the use of metal wire and two Kirschner wires [1]. In 30% of cases following this technique, authors describe secondary displacement of bone fragments due to fixation instability or even complete fixation failure [55]. According to a study by K.L. Hsu et al. of surgical treatment outcomes in 170 patients using the tension band method, fixation failure occurred in 5.2% of cases, minor secondary fragment displacement was noted in 20% of observations, and infectious complications developed in 2.3% of cases [4].

Stable fixation of transverse patellar fractures requires interfragmentary compression using lag screws [51]. The use of cannulated lag screws placed perpendicularly to the fracture line, supplemented by an anterior tension band wire over the patella, achieves absolute stability. In this technique, the wire is passed through the channels within the screws [56]. S. Thelen et al. (2013) demonstrated the superiority of this technique over the traditional one regarding fixation stability and the prevention of secondary bone fragment displacement [57].

S. Gwinner et al. (2016) reported that patellar osteosynthesis using two cannulated screws with a tension band wire passed through them is preferable to single-screw osteosynthesis and the traditional Weber technique due to greater load-bearing stability. Furthermore, the authors noted less pronounced postoperative pain due to reduced soft tissue irritation by the hardware, which in turn promotes early rehabilitation without increasing the risk of secondary bone fragment displacement. These authors also permit the use of lag screws alone in the osteosynthesis of simple patellar fractures to minimize soft tissue trauma. They consider this surgical technique particularly preferable in cases where bone fragment reduction can be achieved closed and the screws inserted percutaneously through separate stab incisions [18]. The scientific literature describes methods of patellar fracture osteosynthesis using non-metallic fixators, including in combination with metal implants. Specifically, a number of surgeons have used polymer polyfilament sutures instead of orthopedic bone wire*** for patellar fracture fixation. The authors report a high proportion of patients in whom successful bone union of the patella was achieved [54, 58].

• Patients with patellar fractures are recommended to undergo open plate osteosynthesis of the patella to fix patellar fragments and create conditions for bone healing [1, 6, 53, 54, 64].

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

Comments. When performing open plate osteosynthesis of the patella, the following implants are used: non-absorbable sterile bone fracture fixation plate with screws***, non-absorbable non-sterile bone fracture fixation plate with screws***, non-absorbable sterile orthopedic bone screw***, non-absorbable non-sterile orthopedic bone screw***.

Osteosynthesis with wires and a tension band wire (orthopedic bone wires and pins***) is not always effective. Its use in comminuted patellar fractures may be associated with poor radiological and, consequently, functional treatment outcomes for patients [54]. Therefore, fixation of patellar fractures can be performed using plates (non-absorbable sterile bone fracture fixation plate with screws***, non-absorbable non-sterile bone fracture fixation plate with screws***, non-absorbable sterile orthopedic bone screw***, non-absorbable non-sterile orthopedic bone screw***). The availability of plate implants for various patellar fracture locations allows for stable osteosynthesis of both simple and comminuted patellar fractures [55, 59, 60, 61]. Plate osteosynthesis is associated with better clinical outcomes, a lower complication rate, and shorter fracture consolidation times compared to wire and pin osteosynthesis in patellar fractures [64].

• Patients with intra-articular bone defects are recommended the most accurate anatomical reconstruction of the articular surface in order to create conditions for bone healing [1, 4, 18, 55, 59].

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

• Patients with patellar fractures are recommended the use of external fixation devices to create conditions for fracture consolidation or temporary fragment fixation [62].

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

• Patients with patellar fractures are recommended intraoperative fluoroscopic control during open plate osteosynthesis of the patella to monitor fragment reduction and implant positioning [1, 4, 27, 28, 55, 59].

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

• Patients with patellar fractures are recommended partial patellectomy (patellar resection, removal of the patella) in the presence of a comminuted fracture of the lower pole of the patella, provided that its osteosynthesis is impossible, in order to restore knee joint function and reduce pain [18, 20, 54].

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

Comments: in the case of a comminuted fracture of the inferior pole of the patella with preservation of a large proximal fragment, achieving bone fragment reduction and stable fixation is difficult. In this case, partial patellectomy can be considered as a treatment method. However, partial resection of the inferior pole reduces the distance between the patella and the tibial tuberosity and may lead to a low-lying patella (patella baja), which is associated with increased patellar pressure on the femoral articular surface. This leads to anterior knee pain and contributes to the development of osteoarthritis [18, 63]. To maintain the functional integrity of the extensor mechanism, it is necessary to preserve the central part of the patella and two-thirds of the articular surface. To protect the reconstructed patellar tendon, a transosseous McLaughlin cerclage suture should be applied for 6 weeks [18]. Partial patellectomy is always preferable to total patellectomy [20].

• Patients with patellar fractures are not recommended to undergo total patellectomy to restore knee function and eliminate pain if reconstructive surgery, reduction, and osteosynthesis are feasible [18, 20, 54].

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

Comments: clinical outcomes following total patellectomy are predominantly unsatisfactory. Patients complain of anterior knee pain, leg weakness, knee instability, and lower limb "buckling". The biomechanical role of the patella in leg extension is recognized by surgeons, and therefore the efforts of the attending physician should be aimed at preserving the patella. Total patellectomy should be considered as an option only in the event of severe patellar osteomyelitis [18, 54].

3.2.4. Specifics of surgical treatment of patellar fractures in children.

• In pediatric patients with displaced patellar fractures, surgical treatment is recommended: open reduction and fixation (bone fragment reduction, open fracture treatment with internal fixation, application of external fixation devices) to stabilize bone fragments and create conditions for bone union [165, 169].

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

Comments: for transverse fractures, screw fixation or tension band wiring is recommended according to guidelines. For longitudinal fractures, screw fixation (arthroscopically assisted if technically feasible) is indicated. For avulsion fractures, fixation with transosseous sutures. Some studies have also mentioned partial patellectomy in displaced or comminuted patellar fractures with satisfactory postoperative results [165, 169].

3.3 Other Treatment

3.3.1. Postoperative analgesia

• For adequate pain management in patients with patellar fractures, it is recommended to use multimodal analgesia, which may include NSAIDs from group M01A (Anti-inflammatory and antirheumatic products, non-steroids), paracetamol**, gabapentinoids, and immediate-release opioids, taking into account age restrictions in the instructions for medical use; if administration is impossible, monomodality should be used [68-69, 193]. Recommended medications with analgesic effects are listed in Appendices A3.1–A3.3.

For NSAIDs, antirheumatic products, and paracetamol**, gabapentinoids: Level of Recommendation A (Level of Evidence – 1).

For opioids: Level of Recommendation C (Level of Evidence – 5).

Comments: adequate pain relief must be provided to the patient with a fracture prior to any manipulations and throughout the entire period of fracture treatment, the duration of which varies significantly depending on the chosen management strategy. When providing pain management in an inpatient setting, orders executed at the emergency medical care stage must be taken into account. In the acute period of trauma, to ensure proper pain control, the patient must be provided with adequate fragment immobilization using a vacuum splint, vacuum mattress, or external fixation device (Kit of components, parts, and tools for assembling external fixation devices for bone fractures).

Among pharmacological strategies, the current consensus is the use of multimodal analgesia (MMA), which involves the use of several analgesic drugs (opioids from group N02A Opioids and non-opioids from groups N02B Other analgesics and antipyretics, M01A Anti-inflammatory and antirheumatic products, non-steroids) with different mechanisms of action, alongside non-pharmacological interventions aimed at affecting the peripheral and/or central parts of the nervous system [70]. This combination allows for more effective pain relief by enhancing the effects of various drugs, which in most cases leads to a decrease in the frequency of prescription and/or doses of opioid analgesics from group N02A Opioids. Thus, MMA improves the risk profile of each drug while providing synergistic pain control using different drug classes. Postoperative MMA may include psychotherapy, physical therapy, NSAIDs, paracetamol**, gabapentinoids, regional anesthesia (single-shot injection or peripheral nerve catheter placement), local injections, and opioids [68].

In modern scientific literature, authors emphasize the use of the lowest effective doses of opioids for the shortest possible duration, avoiding extended-release opioids. As an adjuvant during MMA for adult patients, a single intravenous administration of #dexamethasone** 1.25–20 mg prior to surgery (60 minutes before the incision) can be used, which provides a significant reduction in pain [67].

It must be remembered that the duration of parenteral administration of most NSAIDs (ketorolac**, ketoprofen**, diclofenac**) is limited to two days, which requires timely switching of the patient to oral administration, changing the drug, or coordinating further use with the medical commission. The specific choice of local anesthesia method and medicinal products is made by the attending physician individually in accordance with the patient's characteristics, local protocols, and the equipment of the medical organization.

When prescribing analgesic therapy for children, a single dose should be chosen taking into account the child's weight and age. Preference should be given to analgesics with oral or rectal administration routes, avoiding intramuscular injections.

• In children with patellar fractures, the use of paracetamol** and ibuprofen** is recommended for analgesia [193, 193]. The recommended dosage regimen and age restrictions in accordance with the instructions for medical use are given in Appendix A3.3.

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

• In cases of severe pain and ineffectiveness of paracetamol** and ibuprofen** in children, the use of other non-steroidal anti-inflammatory and antirheumatic drugs (M01A) and narcotic analgesics from the opioid group (N02A) is recommended if there are relevant indications and no contraindications [193].

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

• Patients with patellar fractures are recommended to undergo local blockade or regional anesthesia as part of a postoperative multimodal regimen for pain management [204, 205].

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

3.3.2. Surgical antibiotic prophylaxis

• In the surgical treatment of patients with closed patellar fractures, it is recommended to perform surgical antibiotic prophylaxis (SAP) of surgical site infection with a single preoperative administration of an antibacterial drug to reduce the risk of infectious complications [72-73].

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

Comments. In accordance with international clinical guidelines for the prevention of surgical site infections [74, 72], the objective of SAP is to achieve bactericidal concentrations of the antibacterial drug in tissues exposed to microbial contamination during surgery to prevent surgical site infections. The need for SAP is determined by the surgical wound class of the upcoming operation: SAP is not required for "clean" surgical wounds not associated with the placement of orthopedic implants and metal hardware. SAP should be performed: for clean-contaminated and contaminated surgical wounds; for "clean" surgical wounds involving the placement of orthopedic implants and metal hardware. For infected ("dirty") wounds, SAP is not indicated; antibiotic therapy is administered instead.

• In patients with patellar fractures, it is recommended to use first- and second-generation cephalosporins (cefazolin**, cefuroxime**) as the primary medications for surgical antibiotic prophylaxis during surgical interventions in traumatology and orthopedics; as an alternative in case of beta-lactam antibiotic intolerance—glycopeptide antibiotics (vancomycin**), lincosamides (#clindamycin**) [72]. All medicinal products are prescribed in accordance with age restrictions in the instructions for medical use.

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

Comments. For patients with an unremarkable allergic history and no significant risk factors for methicillin-resistant staphylococcal carriage, first-generation (J01DB) and second-generation (J01DC) cephalosporins (cefazolin**, cefuroxime**) are used for surgical site infection prophylaxis; they are administered intravenously 30 to 60 minutes before the skin incision. In case of beta-lactam allergy, vancomycin** should be prescribed, administered over at least 60 minutes starting the IV infusion 2 hours before the incision, or #clindamycin**. In patients with significant risk factors for methicillin-resistant staphylococcus (MRS) carriage, the prophylaxis regimen must include an antibacterial agent with anti-MRS activity (vancomycin**). In most cases, a single preoperative dose of the antibacterial agent is sufficient for effective prophylaxis. For prolonged procedures or massive blood loss, an additional intraoperative dose of the antibacterial agent should be administered (the approximate timing for intraoperative administration is two half-lives after the preoperative dose). Administration of the antibacterial agent after wound closure in the operating room is inappropriate, even in the presence of established drains.

Single doses of main antibacterial agents for surgical site infection prophylaxis in adult traumatology and orthopedic procedures: cefazolin** 2 g (for patients weighing ≥120 kg — 3 g), cefuroxime** 1.5 g, #clindamycin** 900 mg, vancomycin** 15 mg/kg as a slow IV infusion [72].

Single doses for children should be calculated based on actual body weight in accordance with the enclosed product information: cefazolin** 30–50 mg/kg, cefuroxime** 50 mg/kg, #clindamycin** 10 mg/kg, vancomycin 15 mg/kg; the use of fluoroquinolones during the period of bone and joint system development in the presence of unclosed growth plates is contraindicated due to the risk of arthropathy [72, 132].

Comments. In open fractures, prophylactic administration of antibacterial agents is effective in preventing early infection. The antibacterial agent should be administered as soon as possible after the injury. Cefazolin** is the antibacterial agent of choice; however, in patients with open high-energy fractures with bone displacement and segmental loss, major vascular injury, or heavily contaminated wounds, it is advisable to broaden the spectrum of prescribed antibacterial agents to cover gram-negative pathogens. In such cases, adult patients may be considered for the addition of #gentamicin** (at a dose of 6 mg/kg intravenously once daily) to cefazolin** [76, 77]. An alternative to this combination is #ampicillin + sulbactam** (at a dose of 3.0 g intravenously every 8 hours for 3 days) [78], with the latter being particularly relevant in cases involving the risk of clostridial infection. According to the majority of researchers, in Gustilo-Anderson type III open fractures, antibacterial agents should not be continued for more than 72 hours after soft tissue wound closure [79].

• During the surgical treatment of patients with extremity fractures, it is recommended to perform surgical site infection prophylaxis lasting no more than 24 hours [80].

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

Comments. In accordance with the regulatory documentation in force in the Russian Federation (SanPiN 3.3686-21) and clinical guidelines [80], to achieve an effective concentration of the antibacterial agent in tissues and blood serum at the time of the skin incision, antibacterial agents for surgical site infection prophylaxis should be administered intravenously 30 to 60 minutes before the skin incision, or within 2 hours before the incision in the case of vancomycin**. The maximum duration of prophylactic antibacterial administration must not exceed 24 hours after the end of surgery. In most cases, a single dose of the antibacterial agent is sufficient for effective prophylaxis. Additional doses should be administered during prolonged surgeries when the half-life of the administered antibacterial agent has elapsed since the preoperative dose, creating a risk of the antibacterial concentration dropping below the bactericidal level and increasing the risk of surgical site infections.

3.3.3. Prevention of venous thromboembolic events

• In all patients with fractures and subsequent extremity osteosynthesis, in the absence of active bleeding, it is recommended to implement VTE prophylaxis measures until the patient's normal or expected mobility is restored [195, 196].

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

Comments. Patients with extremity fractures may belong to the moderate or high VTE risk group, depending on patient characteristics, the nature of the sustained trauma (multiple and polytrauma carry a higher risk of DVT), and the anticipated duration of surgery.

To assess the risk of VTE before surgery, it is advisable to use Caprini VTE risk scoring scales (Appendix G1).

Non-pharmacological means of VTE prophylaxis include:

- elastic and/or intermittent sequential pneumatic compression of the lower extremities;

- early mobilization and activation of the patient;

- therapeutic exercises.

All patients with limited mobility, regardless of the degree of VTE risk, are recommended to receive mechanical VTE prophylaxis [82]. All patients with a moderate or high risk of VTE are recommended to receive pharmacological VTE prophylaxis, generally until normal or expected mobility is restored.

Pharmacological VTE prophylaxis in the preoperative period is performed with unfractionated heparin (UFH, sodium heparin**) from the B01AB heparin group or, preferably, with low-molecular-weight heparins (LMWHs) from the B01AB heparin group (Appendices A3.3, A3.4).

• Patients receiving chronic antithrombotic therapy from group B01 who present with a patellar fracture are recommended to undergo VTE prophylaxis and anesthesia based on specialized guidelines [81, 87].

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

• In patients with patellar fractures undergoing conservative treatment and limb immobilization, it is recommended to initiate pharmacological VTE prophylaxis immediately after ruling out ongoing bleeding to prevent complications [81].

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

Comments. LMWHs are the drugs of choice; in their absence, UFH should be used. Subsequently, from days 3–4 depending on the patient's condition, adult patients may be switched to vitamin K antagonists (B01AA) (warfarin**) provided there is adequate dose titration and regular INR monitoring [81].

Features of thromboprophylaxis in pediatric patients

• Hospitalized patients older than 6 months are recommended to undergo bleeding and VTE risk assessment within 24 hours of admission [88] and periodically during their hospital stay [89–91].

Leveled Recommendation CLevel of Evidence 5Level of Evidence C (Level of Evidence – 5).

Comments. No validated VTE risk assessment scales have been developed for pediatric patients, nor have bleeding risk assessment scales for patients receiving anticoagulants; therefore, when deciding on VTE prophylaxis, individual bleeding risk factors (Appendix A3.6), VTE risk factors (Appendix A3.7), and the risk-benefit ratio should be considered [92, 94].

For VTE prophylaxis in children, mechanical and pharmacological methods are used.

• Pediatric patients at high risk for VTE are recommended to be considered for prophylactic doses of UFH or LMWHs from the B01AB group [89, 91, 195].

CER CLEL 5Level of Evidence C (Level of Likelihood/Credibility of Evidence – 5).

Comments. Specific criteria for assessing the risk of thromboembolic events in children with traumatic injuries are lacking. Important criteria include a history of thrombosis and thromboembolism, blood coagulation disorders, and central venous catheter placement.

3.3.4. Blood-conserving technologies

Comments. Systematic reviews and meta-analyses demonstrate that the perioperative use of parenteral ferric iron preparations (B03AC), specifically ferric carboxymaltose**, in adult orthopedic trauma patients, particularly in the postoperative period, is an effective alternative to blood transfusion, as it reduces the proportion of patients receiving blood transfusions, decreases the volume of packed red blood cells transfused, and reduces the incidence of infectious complications, although it does not affect mortality rates [103, 104].

3.3.5. Tetanus prophylaxis

Comments: in accordance with clauses 4156-4157 of the Sanitary Rules and Norms on the Prevention of Infectious Diseases (SanPiN 3.3686-21), emergency tetanus prophylaxis is performed for any injuries involving a breach of the skin and mucous membranes. Emergency tetanus prophylaxis is administered up to the 20th calendar day from the moment of injury [105, 165]. The prescription of drugs for emergency tetanus immunoprophylaxis (vaccines for tetanus prevention (J07AM), specific immunoglobulins (J06BB)) is carried out differentially depending on the presence of documentary confirmation of a preventive vaccination or data from immunological monitoring of anti-tetanus immunity levels, as well as taking into account the nature of the injuries.

Emergency tetanus immunoprophylaxis is carried out, taking into account age restrictions, in the form of:

- passive immunization or seroprophylaxis with human tetanus immunoglobulin, or in its absence, tetanus antitoxin**, taking into account age restrictions;

- active-passive prophylaxis, consisting of the simultaneous administration into different anatomical sites of human tetanus immunoglobulin (or in its absence, tetanus antitoxin**) and tetanus toxoid** (TT);

- emergency revaccination with tetanus toxoid** (or diphtheria-tetanus toxoid with reduced antigen content** - DT-toxoid-M) to stimulate immunity in previously vaccinated individuals [124, 125, 165].

4. Medical Rehabilitation and Sanatorium-Resort Treatment

Currently, the literature presents patellar fracture rehabilitation protocols proposed by individual authors without evidence of their effectiveness, neither in terms of recovery timelines and return to work, nor in terms of complication rates, nor regarding the duration of individual rehabilitation stages.

The selection of rehabilitation means and methods is based on general knowledge about the negative consequences of prolonged joint immobilization and the general principles of restoring joint function based on the mechanisms of action of various physical therapy (PT) modalities and physiotherapeutic factors.

However, further high-quality studies are needed to investigate the efficacy of various rehabilitation concepts.

All patients undergoing conservative and surgical treatment for patellar fractures are recommended to have a consultation with a physical and rehabilitation medicine physician (initial evaluation (examination, consultation) by a physical therapy physician, examination (consultation) by a physical therapist).

Comments: in conservative treatment, rehabilitation for patients with patellar fractures begins immediately after fracture fixation and continues until fracture consolidation is complete. The duration of the immobilization period averages 4 to 8 weeks. After immobilization is removed, it is recommended to conduct rehabilitation in outpatient medical rehabilitation departments or a day hospital, which corresponds to the third stage of rehabilitation. The duration of functional recovery ranges from 8 weeks to 3 months [177, 179, 181, 182, 183, 184, 200].

Rehabilitation after surgical treatment begins immediately after surgery (early rehabilitation) and, as clinically indicated, can continue in the inpatient rehabilitation department until discharge from the hospital (inpatient rehabilitation stage). The need for postoperative immobilization is decided by the operating surgeon depending on the stability of the fracture fixation.

The period of early and inpatient rehabilitation lasts on average 14 days after surgery. This is followed by a period of outpatient rehabilitation, which is divided into the early recovery period (2-3 weeks) and the late recovery period – the subsequent 2-3 weeks [177, 179, 181, 182, 184, 186, 201].

Comments: there is no current consensus on the rehabilitation of patients with patellar fractures, nor are there comparative studies that would allow for greater certainty regarding the method of fracture immobilization, the recommended orthosis, or the duration of the immobilization phase; the angle at which the knee joint is fixed, the timing for initiating knee joint mobilization, and axial loading on the limb. Rehabilitation protocols are developed by the PRM physician in conjunction with the operating surgeon. During the inpatient, outpatient, and day-care rehabilitation stages, rehabilitation is carried out by an MDRT.

Comments. In the conservative treatment of patellar fractures, a plaster cast or hinged orthosis is applied to immobilize the knee joint in extension [180, 184, 185, 189]. Following consultation, the PRM physician develops a rehabilitation program (patient guide) with recommendations for the motor regimen and physical exercises in accordance with the goals and objectives of the immobilization period [179, 181, 182, 183, 184]. The following are prescribed:

- local cryotherapy (A24.01.005.01),

- corrective positioning (elevated position of the limb) A23.30.017.002,

- individual therapeutic exercise sessions for injuries and diseases of the musculoskeletal system (isometric contraction of the thigh and leg muscles, active movements in the ankle and hip joints) A19.03.002.001,

- gait training with axillary crutches as an assistive device A14.30.018.

The duration of the period is determined jointly with the traumatologist and is up to 4–8 weeks. Rehabilitation is performed independently at home or via a telemedicine program under the online supervision of MDRT specialists.

Comments: after the removal of immobilization, the PRM physician draws up an individualized rehabilitation program, the main task of which in the first two weeks is to improve joint mobility up to a range of 30 degrees, in the subsequent 2-3 weeks up to 60 degrees, and thereafter up to 90 degrees. Once knee joint flexion reaches 60 degrees, strengthening of the thigh muscles is initiated [175, 179, 184, 185, 182].

Axial load on the limb is permitted no earlier than 6 weeks after the fracture [174, 81].

Physical exercises of various orientations are the primary means of rehabilitation, whereas physiotherapeutic methods are of secondary importance.

To restore knee flexion/extension, exercise therapy (LFT) for joint trauma in phase 2 (lightened dynamic exercises) (A19.04.001.027), corrective positioning A23.30.017.002, motorized mechanotherapy (A19.30.006), and robotic mechanotherapy (A19.30.006.001) are prescribed,

To improve blood circulation in the limb and normalize muscle tone: hydrokinesiotherapy for bone fractures (A19.03.003.0239), manual lower limb massage (A21.01.009.01), and hardware pneumatic massage (A21.01.001.008).

Upon achieving 90 degrees of knee flexion, following a repeat consultation with a physical and rehabilitation medicine (PRM) physician, the following are prescribed to restore thigh muscle strength and endurance, neuromuscular connections, and coordination: exercise therapy for joint trauma in phase 3 (dynamic exercises with resistance and weights, static exercises) (A19.04.001.003), mechanotherapy for bone fractures (A19.03.003.003), biofeedback training for musculoskeletal injuries and diseases (A19.04.001.014), balance therapy (A19.30.006.001), and restoration of normal gait pattern.

Comments: within the first 48 hours after surgery a consultation with a PRM physician is performed, who determines an individual rehabilitation program prescribing: exercise therapy in the early postoperative period for the musculoskeletal system, individually (isometric exercises for the thigh and lower leg muscles, dynamic exercises for the ankle joint, exercises for healthy limbs) (A19.04.001.038), local cryotherapy for the first 24 hours (A24.01.005.01), corrective positioning (elevated limb position) A23.30.017.002, low-intensity pulsed electrostatic field therapy (A17.30.038), and training in standing up and crutch-assisted walking (A14.30.018).

Upon discharge from the hospital on days 3-5 after surgery, the PRM physician compiles a patient guide to continue rehabilitation at home. Depending on the nature of the surgical intervention, wearing a functional orthosis for up to 14 days and crutch-assisted walking are recommended.

Instructions for wearing an orthosis after surgery are contradictory, ranging from recommendations to wear it 24 hours a day for 3-6 weeks (removing it only for showering), to sometimes recommending wearing the brace only during the day, or only when walking and standing. There is no evidence on which is better. The more complex and unstable the fracture, the more time is required for orthosis wear and knee joint motion restriction. It is generally not recommended to bend the knee more than 90 degrees for 6 weeks [174, 178, 186, 182, 188, 189].

Gradual, unforced knee flexion up to an angle of 30 degrees, achieved over 2 weeks, is added to the previously performed exercises.

Weight-bearing on the operated leg is permitted from the first day after surgery, guided by pain sensation. This means that walking with additional crutch support is allowed, gradually increasing the load on the operated leg depending on pain. Walking without crutch support is permissible after 6 weeks.

Comments: there is no single rehabilitation protocol, but it has been proven that rehabilitation improves the functional outcomes of surgical treatment and accelerates the recovery of the patient's quality of life [173, 177, 180, 201].

Most protocols recommend early gentle mobilization of the knee joint and full axial load in an orthosis fixed in extension. Flexion is allowed up to 30 degrees within 2 weeks after surgery. Some authors assert the necessity of immobilization for 3-6 weeks after surgery, while others consider this an unnecessary restriction [174, 175, 177, 179, 181, 197, 198].

However, the goals of rehabilitation are to restore knee joint mobility and strengthen the muscles. This is achieved through the gradual use of isometric, isotonic, and isokinetic exercises. Thus, the range of motion of the knee joint is gradually increased and restored, pain is reduced, and the weight-bearing capacity of the limb is restored.

At the outpatient stage, the PRM physician draws up an individual rehabilitation program prescribing:

Exercise therapy for joint trauma in phases 1 and 2 individually (A19.04.001.026, A19.04.001.027), in phase 3 (A19.04.001.029), mechanotherapy for bone fractures (A19.03.003.003), biofeedback training for musculoskeletal injuries and diseases (A19.04.001.014), balance therapy (A19.30.006.001), and restoration of normal gait pattern.

Local cryotherapy (A24.01.005.01), hydrokinesiotherapy for bone fractures (A19.03.003.023), manual lower limb massage (A21.01.009.01), hardware pneumatic massage (A21.01.001.008), and therapeutic underwater jet massage (A20.30.010) may be prescribed according to indications.

Crutch-assisted walking training is performed in the presence of pain syndrome and joint swelling.

After 2-4 weeks, the following are prescribed: therapeutic exercise using apparatus and exercise machines for bone fractures (A19.03.003.022), including active dynamic exercises with resistance and weights, static exercises to strengthen thigh muscles; mechanotherapy on motorized or pneumatic mechanotherapy devices for bone fractures (A19.03.003.010, A19.03.003.008), mechanotherapy for bone fractures (A19.03.003.003), robotic mechanotherapy for bone fractures (A19.03.003.004), and support-reaction biofeedback training for bone fractures (A19.03.003.014).

Indications exist for the use of thigh muscle electrical stimulation (A21.31.011), ultraphonophoresis for joint diseases (A22.23.003.002), and low-level laser therapy (A22.02.001) [174, 197].

Full weight-bearing on the limb is permitted no earlier than 3 months after surgery, based on comfort and tolerance. Daily activity is restored in 6-8 weeks. Sports activities are recommended to resume no earlier than 4 months [2, 5, 7, 105, 201].

5. Prevention and Dispensary Observation

Prevention of proximal lower leg fractures consists in citizens observing social safety rules when performing household chores, staying in traffic zones, walking on poor-quality surfaces, and during icy conditions.

A significant share of responsibility in fracture prevention also belongs to state structures, which are obligated to ensure safety to prevent road traffic injuries, as well as to ensure compliance with safety regulations in industries with increased risk of injury.

• Due to the potential risk of complications after treatment, all patients with patellar fractures following discharge from the hospital are recommended to undergo follow-up monitoring by an orthopedic traumatologist to assess functional recovery and rehabilitation [1, 25, 206].

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

Comments: after discharge from the hospital, the patient must be referred to a trauma center or outpatient trauma department with an indication of the treatment performed and detailed recommendations for the continuation of treatment and rehabilitation. This will ensure continuity between the inpatient and outpatient stages of treatment.

Follow-up examinations with radiographs (lower limb radiography) and assessment of functional recovery dynamics are performed at 6 weeks post-surgery (assessment of fracture consolidation degree and possibility of full weight-bearing on the limb), 12 weeks post-surgery (assessment of fracture consolidation degree and possibility of weight-bearing on the limb), 24 weeks post-surgery (assessment of consolidation degree, assessment of functional recovery dynamics), and 1 year post-surgery (assessment of functional treatment outcome and decision on the need and timing for implant removal).

6. Organization of Medical Care

Clinical application of recommendations: Traumatology and Orthopedics, Anesthesiology and Intensive Care, Medical Rehabilitation, Health Organization and Public Health.

Purpose of the clinical guidelines: The clinical guidelines were developed to improve the quality of medical care and standardize diagnostic and treatment algorithms for patients with patellar fractures.

Indications for planned hospitalization:

- the presence of a displaced patellar fracture in the patient, detected during follow-up examinations by an outpatient traumatologist;

- unsatisfactory result of conservative treatment: secondary displacement of fragments, absence of signs of fracture union after conservative treatment; secondary displacement or migration of implants after osteosynthesis [1, 25-28].

Indications for emergency hospitalization:

Patients with suspected or confirmed patellar fracture must be referred to a hospital to determine the need for emergency hospitalization. Indications for emergency hospitalization include:

• patellar fracture with fragment displacement;

• open patellar fracture;

• gunshot fracture of the knee joint region;

• patellar fracture accompanied by major vascular and nerve injuries;

• patellar fracture as part of polytrauma [1, 25-28].

Indications for emergency hospitalization in patellar fracture are determined based on:

1) the presence of patient complaints characteristic of a patellar fracture;

2) the presence of characteristic clinical signs of a patellar fracture;

3) the presence of radiological signs of a patellar fracture in the patient.

Indications for patient discharge from the hospital:

1. Internal fixation of the fracture was performed using hardware (using the following implants: non-absorbable non-sterile orthopedic bone screw***, non-absorbable sterile orthopedic bone screw***, dynamic bone screw***, absorbable orthopedic bone screw***, cannulated compression bone screw***, orthopedic bone pins and wire***, non-absorbable sterile bone fixation screw plate***, non-absorbable non-sterile bone fixation screw plate***) or stabilization with an external fixation device using the following implants: set of assemblies, parts, and instruments for assembling external fixation devices for bone fractures***, or adequate plaster immobilization was performed during conservative treatment;

2. Phase I rehabilitation was performed;

3. No acute infectious process is present;

4. Refusal of the patient or their legal guardians in case of legally established incapacity of the patient to continue inpatient treatment (the reason for refusal must be recorded in the medical chart with the personal signature of the patient or their guardians).

7. Additional Information

No additional information is required.

Criteria for Evaluating the Quality of Medical Care

References

Appendix A1. Working Group Composition

1. Belenky I.G., MD, Professor, State Budgetary Institution "Saint Petersburg I.I. Dzhanelidze Research Institute of Emergency Medicine", Saint Petersburg, member of ATOR.

2. Bozhkova S.A., MD, Federal State Budgetary Institution "R.R. Vreden National Medical Research Center of Traumatology and Orthopedics" of the Russian Ministry of Health, Saint Petersburg, member of ATOR.

3. Geroyeva I.B., MD, Professor, Federal State Budgetary Institution "N.N. Priorov National Medical Research Center of Traumatology and Orthopedics" of the Russian Ministry of Health, Moscow.

4. Zorin V.I., PhD, Associate Professor, Federal State Budgetary Institution "G.I. Turner National Medical Research Center for Children's Orthopedics and Trauma" of the Russian Ministry of Health, Saint Petersburg.

5. Kleymenova E.B., MD, Professor, Federal State Budgetary Institution "N.N. Priorov National Medical Research Center of Traumatology and Orthopedics" of the Russian Ministry of Health, Moscow.

6. Lukyanov S.A., PhD, Federal State Budgetary Institution "G.I. Turner National Medical Research Center for Children's Orthopedics and Trauma" of the Russian Ministry of Health, Saint Petersburg.

7. Mayorov B.A., PhD, State Budgetary Institution "Saint Petersburg I.I. Dzhanelidze Research Institute of Emergency Medicine", Pavlov First Saint Petersburg State Medical University, Saint Petersburg, member of ATOR.

8. Nazarenko A.G., MD, Professor of the RAS, Federal State Budgetary Institution "N.N. Priorov National Medical Research Center of Traumatology and Orthopedics" of the Russian Ministry of Health, Moscow, Vice President of ATOR.

9. Novikov V.A., PhD, Federal State Budgetary Institution "G.I. Turner National Medical Research Center for Children's Orthopedics and Trauma" of the Russian Ministry of Health, Saint Petersburg.

10. Otdelyonov V.A., PhD, Federal State Budgetary Institution "N.N. Priorov National Medical Research Center of Traumatology and Orthopedics" of the Russian Ministry of Health, Moscow.

11. Sergeev G.D., PhD, State Budgetary Institution "Saint Petersburg I.I. Dzhanelidze Research Institute of Emergency Medicine", Saint Petersburg, member of ATOR.

Conflict of interest.

The working group on drafting the clinical guidelines for the treatment of patellar fractures has no conflicts of interest.

Appendix A2. Methodology for Developing Clinical Guidelines

Target audience for these clinical guidelines:

1. Orthopedic trauma surgeons

2. Surgeons

3. General practitioners (family physicians)

4. Medical rehabilitation physicians

5. Physical and rehabilitation medicine physicians

5. Pediatric surgeons

Stages of evaluating the levels of evidence and grades of recommendation:

1. Definition of search and selection criteria for publications on clinical trials (CT) regarding the efficacy and/or safety of the medical intervention described in the recommendation statement.

2. Systematic search and selection of CT publications in accordance with the previously defined criteria.

Systematic search and selection of clinical trial publications:

The evidence base for the recommendations consisted of publications retrieved via information retrieval in the following databases: Central Scientific Medical Library (CSML) "Russian Medicine", MEDLINE (US NLM), and COCHRANE Library; scientific electronic libraries eLibrary.ru and "CyberLeninka"; as well as on the Internet using Yandex, Google, and Google Scholar search engines, by reviewing leading specialized peer-reviewed domestic medical journals on the subject and treatment guidelines for fractures from the international Association for Osteosynthesis AO/ASIF.

Table 1. Scale for assessing levels of evidence (LE) for diagnostic methods (diagnostic interventions)

Table 2. Scale for assessing the levels of evidence (LE) for prevention, treatment, and medical rehabilitation methods, including those based on natural therapeutic factors (preventive, therapeutic, and rehabilitation interventions)

Table 3. Scale for assessing the grades of recommendation (GR) for prevention, diagnostic, treatment, and medical rehabilitation methods, including those based on natural therapeutic factors (preventive, diagnostic, therapeutic, and rehabilitation interventions)

Procedure for updating clinical guidelines.

The mechanism for updating clinical guidelines provides for their systematic updating 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 well-founded additions/comments to previously approved clinical guidelines, but no more frequently than once every 6 months.

Appendix A3. Reference Materials

Appendix A3.1 Pain management recommendations for major musculoskeletal trauma (surgical fixation of long bone fractures or complex joint fractures, extensive soft tissue trauma, extensive surgery, etc.) in adults

The table shows analgesic drugs and their dosing regimens in accordance with the Clinical Guideline for Pain Management in Acute Musculoskeletal Trauma [70].

¹ In adults, paracetamol is not recommended for use as an analgesic for more than 5 days without prescription and medical supervision.

Appendix A3.2 Pain management recommendations for non-surgical musculoskeletal trauma (closed fractures, superficial wounds, etc.) in adults

Appendix A3.3. Recommendations for Postoperative Analgesia in Children

* In children under 12 years of age, morphine is the preferred choice if opioids (N02A) are required, as the use of tramadol** is associated with a higher risk of adverse reactions [156, 157].

† Not recommended for use in children because its metabolite accumulates in the body and provokes seizures upon repeated administration [158].

Appendix A3.4 Recommended intervals between prophylactic anticoagulant administration and neuraxial interventions in adults [127]

Please note that spinal or epidural anesthesia can be performed only 12 hours after administering a dose of LMWH B01AB and no earlier than 4–6 hours after administering UFH from the B01AB group (while aPTT or ACT values must be within the normal range) [87].

Appendix A3.5 Recommended dosing regimen of low-molecular-weight heparins from the heparin group B01AB for the prevention of high-risk VTE in conservative treatment and orthopedic surgery in adult patients at high risk for VTE

Please note that spinal or epidural anesthesia can be performed only 12 hours after administering a dose of low-molecular-weight heparins from the heparin group (B01AB) and no earlier than 4–6 hours after administering UFH (heparin sodium**) (while aPTT or ACT values must be within the normal range) [157, 158].

Appendix A3.6 Bleeding risk factors in children aged 6 months to 18 years [109, 98, 113]

Notes:

1. If the patient meets at least one "NOT recommended" criterion, avoid pharmacoprophylaxis, as the risk outweighs the benefit.

2. If the patient has at least one relative contraindication criterion, consider withholding pharmacoprophylaxis.

3. Consider consultation with a hematologist if the patient is at high VTE risk with a high bleeding risk [90].

4. Uncontrolled hypertension is defined as systolic or diastolic blood pressure above the 95th percentile for age, height, and sex [91].

5. Coagulopathy is defined as INR > 1.5, aPTT > 44 s, fibrinogen < 100 g/dL, or platelets < 50,000/μL.

Appendix. VTE risk factors in children aged 6 months to 18 years [113, 164]

Notes:

− Reduced mobility is defined as a decrease in mobility compared to baseline level or inability to participate in physical therapy.

− Central venous access device is defined as a non-tunneled catheter, tunneled catheter, or central venous catheter.

− Extensive burn is defined as a burn involving more than 50% of the body surface area.

− Major surgery refers to procedures lasting longer than 45 minutes.

− Critically ill patients are defined as those admitted to the intensive care unit or critical care unit (receiving inotropic support, mechanically ventilated).

− Thrombophilic states include antithrombin deficiency, protein C or S deficiency, factor V Leiden, or prothrombin gene mutation.

− Active malignancy is defined as receiving chemotherapy/radiation therapy within the preceding 6 months.

− Active inflammatory disease includes Kawasaki disease, inflammatory bowel disease, systemic lupus erythematosus, or nephrotic syndrome.

− Estrogen therapy includes systemic hormonal contraceptives (G03A) or estrogen replacement therapy within the last 2 weeks.

− Obesity is defined as a BMI above the 95th percentile for age.

Key:

Low VTE risk:

• No altered mobility and 0-1 risk factors

Moderate VTE risk:

• No mobility impairment and 2-3 risk factors

• Altered mobility and 0-1 other risk factors

High VTE risk:

• No mobility impairment and ≥4 risk factors

• Altered mobility and ≥2 other risk factors

Thromboprophylaxis recommendation

Appendix B. Physician Action Algorithms

Appendix B1. Physician action algorithm for suspected patellar fracture

Appendix B2. Assessment of Cardiovascular Surgical Risk

Notes and abbreviations:

RF – cardiovascular risk factors (arterial hypertension, smoking, dyslipidemia [elevated total cholesterol >4.9 mmol/L and/or LDL cholesterol >3 mmol/L and/or HDL cholesterol <1.0 mmol/L in men, <1.2 mmol/L in women, and/or triglycerides >1.7 mmol/L], diabetes mellitus, family history of premature cardiovascular disease [<55 years for men and <65 years for women]);

CVD – cardiovascular diseases (coronary artery disease, cerebrovascular disease, peripheral atherosclerosis, chronic heart failure, pulmonary hypertension, valvular heart disease, cardiomyopathies);

rRCRI – reconstructed RCRI index (See Appendix G2);

FS – functional status (the patient's ability before the injury to independently climb 2 flights of stairs without stopping).

*- regional vascular center or specialized cardiological department.

Appendix C. Patient Information

Patellar fractures are an injury requiring specialized treatment in a trauma department. Conservative treatment is possible only for undisplaced fractures or with minimal fragment displacement (less than 2 mm) and an intact extensor mechanism. It involves immobilization in a plaster cast or knee brace with the limb extended for up to 6 weeks. The main disadvantages of such treatment are the high probability of knee joint contractures and a decrease in quadriceps femoris strength.

Surgical treatment is indicated for all displaced fractures, rupture of the extensor mechanism, and open injuries. Surgical tactics depend on the fracture type. Transverse fractures are treated with tension-band wiring (metal or polymeric, with K-wires or screws), which restores knee joint anatomy and creates conditions for fracture healing. Comminuted fractures may require fixation with plates or cannulated screws.

Rehabilitation begins immediately after surgery and includes passive and active movements in the knee joint, physiotherapy procedures, and exercises aimed at restoring quadriceps femoris strength. The timing of limb weight-bearing depends on the type of osteosynthesis. On average, weight-bearing on the injured limb is possible 8–12 weeks after surgery. Full recovery of knee joint function takes an average of 3–6 months.

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

Appendix G1. Caprini Risk Assessment Scale for Venous Thromboembolism (Caprini J.)

Russian name: Caprini Risk Assessment Model for venous thromboembolism.

Original name: Caprini Score for Venous Thromboembolism.

Source: Lobastov K.V., Barinov V.E., Schastlivtsev I.V., Laberko L.A. Caprini scale as a tool for individual stratification of the risk of postoperative venous thromboembolism in a high-risk group. Khirurgiya. Zhurnal im. N.I. Pirogova. 2014; (12):16-23.

Type: scale.

Purpose: assessment of venous thromboembolism risk.

Content (template):

1 point

Age 41–60 years

Lower extremity edema

Varicose veins

Body mass index > 25 kg/m²

Minor surgery

Sepsis (< 1 month)

Severe pulmonary disease (including pneumonia < 1 month)

Oral contraceptive use, hormone replacement therapy

Pregnancy and postpartum period (< 1 month)

History of: unexplained stillbirths, spontaneous abortions (≥3), premature delivery with gestosis, or intrauterine growth restriction

Acute myocardial infarction

Chronic heart failure (< 1 month)

Bed rest in a non-surgical patient

History of inflammatory bowel disease

History of major surgery (< 1 month)

Chronic obstructive pulmonary disease

2 points

Age 61–74 years

Arthroscopic surgery

Malignant neoplasm105

Laparoscopic procedure (duration >45 min.)

Bed rest > 72 h

Limb immobilization (< 1 month)

Central venous catheterization

Major surgery (duration >45 min.)

3 points

Age > 75 years

Personal history of VTE

Family history of VTE

Factor V Leiden mutation

Prothrombin G20210A mutation

Hyperhomocysteinemia

Heparin-induced thrombocytopenia

Elevated anticardiolipin antibodies

Lupus anticoagulant

5 points

Stroke (< 1 month)

Multiple trauma (< 1 month)

Major joint arthroplasty

Femur and lower leg fractures (< 1 month)

Spinal cord injury/paralysis (< 1 month)

Key: Depending on the score obtained from history taking and patient examination, the patient is assigned to a specific risk group:

• low risk: 0–1 points;

• moderate risk: 2 points;

• high risk: 3–4 points;

• very high risk: 5 points or more.

Appendix G2. Revised Cardiac Risk Index (rRCRI)

Russian name: Reconstructed Revised Cardiac Risk Index for non-cardiac surgical procedures.

Original name: Reconstructed Revised Cardiac Risk Index (rRCRI).

Source: Davis C., Tait G., Carroll J. et al. The Revised Cardiac Risk Index in the new millennium: a single-centre prospective cohort re-evaluation of the original variables in 9,519 consecutive elective surgical patients. Can. J. Anaesth. 2013; 60(9): 855-863.

Type: scale.

Purpose: prediction of the risk of perioperative cardiac complications in noncardiac surgery: myocardial infarction, pulmonary edema, ventricular fibrillation or cardiac arrest, complete AV block.

Content:

1. High-risk surgery (intrathoracic, intra-abdominal, or suprainguinal vascular surgery) – 1 point.

2. Ischemic heart disease (myocardial infarction, positive stress test, angina pectoris, nitroglycerin use, pathological Q wave on ECG) – 1 point.

3. Heart failure (history of heart failure, pulmonary edema, paroxysmal nocturnal dyspnea, bilateral pulmonary rales, gallop rhythm, pulmonary congestion on chest X-ray) – 1 point.

4. TIA/Stroke – 1 point.

5. Creatinine clearance <30 ml/min – 1 point.

Scoring:

• total score of 0 – low risk of cardiovascular complications;

• a total score of 1 – moderate risk of cardiovascular complications;

• a total score of 2 or more – high risk of cardiovascular complications.

Notes:

The RCRI index was developed in 1977 [128] to predict the risk of perioperative cardiac complications in non-cardiac surgery. It was validated in the Lee study [129], and in 2013 [130] it was revised and re-validated based on clinical risk factors (the criterion "creatinine level >176.8 µmol/L" was replaced by "creatinine clearance <30 ml/min", and the clinical criterion "insulin-dependent diabetes mellitus" was removed), which is why it is called the reconstructed index. It includes 5 parameters, each assigned 1 point. This particular version of the index is recommended by the Russian Society of Cardiology [34].