Knee ligament injuries: clinical guidelines

List of Abbreviations

AO – Association for Osteosynthesis

BTB – bone-patellar tendon-bone autograft

PCA – patient-controlled analgesia

CT – computed tomography

PT – physical therapy

MMA – multimodal analgesia

MRI – magnetic resonance imaging

NSAIDs – nonsteroidal anti-inflammatory drugs of group M01A Anti-inflammatory and antirheumatic products, non-steroids

ACL – anterior cruciate ligament

PCL – posterior cruciate ligament

MCL – medial collateral ligament

LCL – lateral collateral ligament

RA – regional anesthesia

PRM – physical and rehabilitation medicine

PTL – physical therapy treatment

Surgical antibiotic prophylaxis

CNS – central nervous system

EMS – electrical muscle stimulation

NMDA antagonists – a class of anesthetics that inhibit the action of the N-methyl-D-aspartate (NMDA) receptor

TAP – transversus abdominis plane block

ST – hamstring tendon autograft

Terms and Definitions

Injury of the anterior cruciate ligament of the knee is a pathological condition characterized by partial or complete disruption of the integrity of the anterior cruciate ligament.

Injury of the posterior cruciate ligament of the knee is a pathological condition characterized by partial or complete disruption of the integrity of the posterior cruciate ligament.

Injury of the medial collateral ligament of the knee is a pathological condition characterized by partial or complete disruption of the integrity of the medial collateral ligament.

Injury of the lateral collateral ligament of the knee is a pathological condition characterized by partial or complete disruption of the integrity of the lateral collateral ligament.

1. Brief information on the disease or condition

1.1 Definition of the disease or condition

Injury of the anterior cruciate ligament of the knee is a pathological condition characterized by partial or complete disruption of the integrity of the anterior cruciate ligament [1].

The anterior cruciate ligament (hereinafter ACL) has a complex anatomical structure. It is a cord originating in the posterior part of the medial surface of the lateral femoral condyle. It then extends anteriorly and medially and is distally attached to the tibia. On average, the length of the ACL in adults is 32 mm (ranging from 22 to 41 mm); diameter is 10 mm (ranging from 7 to 12 mm); the diameter expands from the proximal to the distal part from 33 to 42 mm². In the structure of the ACL, two bundles are distinguished according to their anatomical direction: the smaller anteromedial bundle and the thicker posterolateral bundle. The anteromedial bundle is taut during flexion, while the posterolateral bundle is taut during extension of the knee joint. In the extended position, both bundles are parallel to each other. However, during knee flexion, the bundles cross each other. Therefore, the anterior drawer test is more informative for anteromedial bundle injuries, and the Lachman test is more informative for posterolateral bundle injuries.

The main blood supply to the anterior cruciate ligament is from the middle genicular artery. The distal part is supplied by branches of the lateral and medial inferior genicular arteries. The ligament is surrounded by a synovium where the terminal branches of the middle and inferior arteries form a vascular network. From the synovium, blood vessels penetrate horizontally into the ligament and form anastomoses with the longitudinally oriented intraligamentous vascular network. The density of blood vessels within the ligament is heterogeneous.

The anterior cruciate ligament provides approximately 85% of the total restraining force during anterior tibial translation. It also prevents excessive medial deviation and rotational movement of the tibia. Together with the posterior cruciate ligament, the anterior cruciate ligament forms the instantaneous center of knee rotation, thereby controlling joint kinematics. While the anteromedial bundle is the primary stabilizing factor against anterior tibial translation, the posterolateral bundle stabilizes the knee in full extension, especially under rotational loads.

The posterior cruciate ligament (PCL) is one of the key structures ensuring knee joint stability. The PCL is located inside the knee joint and is one of two cruciate ligaments that cross in an "X" shape. It originates from the inner surface of the medial femoral condyle. From there, it runs downward and backward, attaching to the posterior intercondylar area of the tibia. This arrangement allows the PCL to effectively control tibial motion, preventing its posterior displacement relative to the femur. The PCL consists of dense fibrous connective tissue, which provides high strength and resistance to stretching. The collagen fibers forming the ligament are organized into bundles, ensuring its mechanical strength. There are two main bundles: the anterolateral and posteromedial. These bundles work together to stabilize the knee joint in various positions and under different loads. Each bundle becomes taut depending on the knee flexion angle, allowing the ligament to adapt to changes in joint position. Although the PCL is extremely strong, it also possesses a certain degree of elasticity, enabling it to absorb and distribute loads generated during movement. This is especially important for preventing injuries during sudden movements.

The PCL receives blood supply from branches of the middle genicular artery and is innervated by branches of the tibial nerve.

The PCL plays an important role in the biomechanics of the knee joint, and its integrity is critical for normal joint function, particularly in athletes.

The medial collateral ligament (MCL) is one of the key structures ensuring knee joint stability. The MCL originates from the medial epicondyle of the femur. The ligament then runs downward and slightly backward, attaching to the medial surface of the tibia. This attachment is located on average 8 centimeters below the joint line level. The ligament consists of two main layers – superficial and deep. The superficial layer is longer and wider, running from the femur to the tibia and providing the bulk of the stabilizing function. The shorter deep layer is located closer to the joint and is integrated with the joint capsule and medial meniscus. The position of the MCL makes it a key structure for maintaining medial knee stability, especially under loads that may cause inward tibial deviation. The main function of the MCL is to stabilize the inner aspect of the knee joint, preventing inward deviation (valgus stress). This is particularly important during lateral movements and turns. The medial collateral ligament has a rich blood supply from branches of the femoral and tibial arteries. Innervation is provided by branches of the femoral and tibial nerves.

The lateral collateral ligament (LCL), also known as the fibular collateral ligament, is one of the main structures ensuring knee joint stability. It originates from the lateral epicondyle of the femur and attaches to the fibular head. It runs along the outer side of the knee joint without fusing with the joint capsule or the lateral meniscus, which distinguishes it from the medial collateral ligament. The LCL has a round and dense structure. Its fibers consist of dense connective tissue, which provides strength and resistance to stretching.

The main function of the LCL is to prevent excessive outward tibial deviation (varus stress). It also plays a role in stabilizing the knee joint during rotational movements. The lateral collateral ligament receives blood supply from branches of the inferior lateral genicular artery. Innervation is provided via branches of the fibular nerve [1-4].

Depending on the type of injury, partial (incomplete) or complete damage to the ligamentous apparatus of the knee joint occurs. Additionally, combined injuries of the ACL along with damage to the joint capsule, menisci, posterior cruciate ligament, and collateral ligaments are frequently observed. As a result of knee dislocation or subluxation, trauma to the cartilage tissue and depression fractures of the femoral and tibial condyles occur.

Thus, when traumatic energy is applied, a complex of injuries to the intra-articular structures of the knee joint most commonly arises. Recognizing all of its elements is an essential stage of diagnosis and planning for conservative or surgical treatment, the goal of which is to restore the knee joint stability necessary for proper function [1, 3-6].

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

The cause of ligamentous apparatus injury is direct trauma to the knee joint, i.e., a direct blow to the knee area. The majority of anterior cruciate ligament (ACL) injuries are caused by the so-called non-contact mechanism of knee injury: when, with a fixed foot, valgus deformation of the knee joint occurs, along with sudden rotation in the knee joint within a flexion range of 10⁰-30⁰ and a sharp contraction of the quadriceps femoris muscle [2, 3]. Less common causes include hyperextension of the knee joint, falling backward with maximal knee flexion, and high-energy trauma.

1.3 Epidemiology of the Disease or Condition

Ruptures of the knee ligamentous apparatus are among the most severe and frequent intra-articular injuries, ranking second after meniscus tears. Such injuries occur predominantly in young, active working-age patients who engage in physical culture and sports. Tears of the anterior cruciate ligament predominate among injuries to the capsular-ligamentous apparatus of the knee joint [3].

Epidemiological studies typically indicate the number of ACL ruptures per 1,000 individuals per year. Current US estimates suggest 32,000 to 320,000 ACL ruptures occur annually. In Scandinavia, there are approximately 20,000 ACL ruptures per year. In Germany, there are about 100,000 ruptures per year. Posterior cruciate ligament (PCL) injuries are less common than anterior cruciate ligament (ACL) injuries. In the US, the incidence of isolated PCL injuries is estimated at approximately 3-20% of all knee ligament injuries. However, this figure may vary depending on the data source and diagnostic methods [5].

Risk factors include a valgus knee alignment. The ratio of ACL tears in women compared to men in sports is approximately 3:1 [6]. ACL injuries are most frequently observed during alpine skiing, football, basketball, and rugby (American football). PCL injuries most commonly result from motor vehicle accidents or sports injuries, such as falls onto a flexed knee or blows to the anterior lower leg. It is important to note that isolated PCL injuries are less common than complex injuries involving multiple knee joint structures [7]. Over the past few years, the number of ACL injuries in children and adolescents has increased, and it is currently estimated that 50% of all patients with an ACL rupture are between 15 and 25 years old [8].

1.4 Features of Coding the Disease or Condition

M23.5 Chronic instability of knee;

M23.6 Other spontaneous disruption of knee ligament(s);

S83.4 Sprain, rupture and strain of (lateral)(medial) collateral ligament of knee;

S83.5 Sprain, rupture and strain of (anterior)(posterior) cruciate ligament of knee;

S83.6 Sprain, rupture and strain of other and unspecified parts of knee;

S83.7 Traumatism of multiple structures of knee.

1.5 Classification of the disease or condition

• Acute ruptures of ACL, PCL, LCL, MCL (duration less than 4 months);

• Chronic ruptures of the ligamentous apparatus and chronic knee instability (duration more than 4 months);

• Partial ruptures and scarring of knee ligaments;

• Complete rupture of ACL, PCL, LCL, MCL;

• Avulsion of ligaments with a bone fragment [2-4, 9].

1.6 Clinical presentation of the disease or condition

Patients complain of pain of varying nature and intensity, and tenderness upon palpation along the joint line. Characteristic features include a sharp restriction of motion in the knee joint, as well as hemarthrosis or joint effusion. Impingement of the torn ACL and/or PCL stump between the articular surfaces may be accompanied by clicking, popping, or crunching, and can cause joint locking, which is usually short-lived and easily resolved. Knee pain may be provoked by walking, descending or ascending stairs, or running. Gait changes following ligament rupture, particularly in the acute phase, present as an antalgic gait. Muscle hypotrophy of the thigh or weakness of the quadriceps muscle (in chronic injuries) may be present due to limited weight-bearing on the affected limb. There is a history of trauma [1-4, 9].

Complaints: pain in the knee joint area, impairment and severe pain during flexion and extension of the knee joint, knee joint instability, swelling, and edema in the knee joint area.

History: a history of trauma, with the patient describing a characteristic injury mechanism.

The classic mechanism of injury is a sudden rotation of the knee joint within a flexion range of 10⁰-30⁰ coupled with a sharp contraction of the quadriceps femoris muscle while the foot is fixed [2, 3].

In some cases, ligament rupture may be caused by hyperextension or sharp full flexion of the knee joint during a fall backward, or by a direct blow to the knee area.

2. Diagnostics, medical indications and contraindications for diagnostic methods

Criteria for diagnosing/establishing an ACL rupture:

1) Complaints (pain, restriction of movement in the knee joint, swelling or edema in the knee area, knee instability, joint locking);

2) Anamnestic data (indication of a characteristic knee injury mechanism);

3) Physical examination (clinical examination data and test results);

4) Laboratory tests;

5) Instrumental examinations.

2.1 Complaints and Anamnesis

2.2 Physical Examination

During physical examination, it is necessary to pay attention to the patient's gait, examine both knee joints and assess for joint effusion or smoothing of the knee contours, note the integrity and condition of the skin, tenderness upon palpation of the joint line, posterior joint pain upon deep flexion, inability to achieve full extension of the lower leg at the knee joint, and the position of the patella.

Comments:

Lachman test technique: The patient lies supine, with the knee flexed to 15-30 degrees. The examiner holds the thigh with one hand while displacing the lower leg anteriorly with the other. The quadriceps and knee flexors must be completely relaxed.

• Evaluation. The anterior cruciate ligament is injured if there is anterior translation of the tibia relative to the femur. The endpoint of translation should be indistinct and gradual, without a hard stop. A distinct endpoint indicates joint stability and the absence of an anterior cruciate ligament injury. A firm endpoint with 3 mm of anterior displacement confirms the integrity of the anterior cruciate ligament, whereas displacement of 5 mm or more indicates a partial or complete tear of the anterior cruciate ligament. With an anterior drawer of over 5 mm, comparing with the contralateral knee is useful to exclude congenital hypermobility (dysplastic syndrome) of the joint ligaments. A positive Lachman test confirms the presence of an anterior cruciate ligament injury.

Anterior drawer test at 90 degrees of flexion technique: The patient lies supine, with the knee flexed to 90 degrees and the hip flexed to 45 degrees. The examiner grasps the patient's lower leg in the upper third with both hands and, with relaxed knee flexors, pulls it anteriorly. The test is performed in a neutral position; 15 degrees of external foot rotation allows assessment of anteromedial instability, while 30 degrees of internal foot rotation provides information on anterolateral instability.

• Evaluation. A visible and palpable anterior drawer (indistinct endpoint of anterior tibial translation) is detected in cases of anterior cruciate ligament rupture.

Posterior drawer test at 90 degrees of flexion technique: The patient lies supine, with the knee flexed to 90 degrees and the hip flexed to 45 degrees. The examiner grasps the patient's lower leg in the upper third with both hands and, with relaxed knee flexors, pulls it posteriorly and anteriorly. The test is used to assess posterior instability.

• Evaluation. A visible and palpable posterior drawer (indistinct endpoint of posterior tibial translation) is detected in cases of posterior cruciate ligament rupture.

The Hughston test (also known as the posterolateral drawer test) is used to assess posterolateral knee stability and to detect injuries of the posterior cruciate ligament (PCL) and the lateral complex. Patient position: The patient lies supine with the knee flexed at 90 degrees and the hip flexed to about 45 degrees. The patient's foot rests on the table. The examiner stands at the side of the patient and stabilizes the foot to prevent movement. The examiner applies a force to the proximal tibia, attempting to displace it posteriorly and laterally. This maneuver places stress on the posterolateral structures of the knee.

• Evaluation: If excessive displacement or instability is felt during the test, it may indicate injury to the posterolateral structures of the knee, including the PCL and lateral stabilizers

The varus stress test is used to assess the integrity of the fibular collateral ligament and the lateral structures of the knee joint. This test helps detect lateral knee instability. Patient position: The patient lies supine. The knee of the tested leg is slightly flexed (typically at an angle of about 20–30 degrees). The examiner stands or sits by the patient's side. With one hand, the examiner stabilizes the femur, and with the other hand, grasps the tibia just above the ankle level. The examiner applies a slow and controlled force to the medial aspect of the knee joint, creating a varus stress. This maneuver is aimed at testing the stability of the lateral side of the knee.

• Evaluation: If excessive displacement or opening of the lateral joint space is felt during the test compared to the normal leg, it may indicate injury to the fibular collateral ligament or other lateral structures.

The valgus stress test is used to assess the integrity of the tibial collateral ligament and the medial structures of the knee joint. This test helps detect medial knee instability. Patient position: The patient lies supine. The knee of the tested leg is slightly flexed (typically at an angle of about 20–30 degrees), which relaxes the joint capsule and isolates the stress on the ligaments. The examiner stands or sits by the patient's side. With one hand, the examiner stabilizes the femur from the outside, and with the other hand, grasps the tibia just above the ankle level. The examiner applies a slow and controlled force to the lateral aspect of the knee joint, creating a valgus stress. This maneuver is aimed at testing the stability of the medial side of the knee.

• Evaluation: If excessive displacement or opening of the medial joint space is felt during the test compared to the normal leg, it may indicate injury to the tibial collateral ligament or other medial structures.

2.3 Laboratory Diagnostics

• All patients diagnosed with knee ligament tears for whom surgical treatment is planned are recommended to undergo the following diagnostic laboratory tests:

- complete blood count;

- urinalysis;

- general clinical blood biochemistry analysis;

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

- determination of hepatitis B virus surface antigen (HBsAg) in the blood;

- determination of class G antibodies (anti-HCV IgG) to hepatitis C virus in the blood;

- determination of antibodies to Treponema pallidum in the blood;

- determination of antibodies of classes M and G (IgM, IgG) to human immunodeficiency virus HIV-1/2 and p24 antigen (Human immunodeficiency virus HIV 1/2 + Agp24) in the blood;

- coagulogram (screening hemostasis test);

- determination of the international normalized ratio (INR) [81, 82, 83].

LoE 3Grade of recommendation B (level of evidence 3).

Comments: no specific laboratory tests have been developed for diagnosis.

2.4 Instrumental Diagnostics

Comments: radiographs may reveal subluxation of the articular surfaces; this is a mandatory imaging method with high diagnostic value that allows assessment of the involvement of bony structures (to rule out fracture) and signs of osteoarthritis (narrowing of the joint space, osteophytes, subchondral bone cysts, sclerosis), as well as determination of patellar position. In patients with acute knee trauma, the decision to perform standard knee radiography should be based on the Ottawa knee rules (adopted for adults and children over 5 years of age). If necessary, along with anteroposterior and lateral projections, additional views are used: the axial view and 45-degree knee flexion [115]. If the injury is chronic, weight-bearing radiography may be ordered. Stress radiography is used for surgical planning [116].

• All patients are recommended to undergo magnetic resonance imaging of the knee joint to assess the condition and injuries of the ligamentous apparatus [13, 14, 79, 80, 120, 121].

GPR BLEL 2Grade of Recommendation B (Level of Evidence 2).

Comments: Currently, MRI is one of the primary diagnostic methods for knee pathology. This non-invasive method allows the detection of more than 70–89% of meniscus tear cases, especially in acute presentations when history and physical examination findings are inconclusive. MRI can characterize a meniscus tear (location, pattern, length, and depth), assess the integrity of the anterior cruciate ligament and other knee ligaments, evaluate cartilage and subchondral bone, determine the presence of a meniscal cyst, assess the extensor mechanism (patellar ligament, quadriceps tendon), and identify other associated pathology. The most frequent sign of a meniscus tear is a split within the meniscus shadow or a defect of the meniscal tissue in its normal location with its presence in an atypical site [13, 14, 79, 80, 120, 121].

Comments: Ultrasound of the knee joint can have a sensitivity of 83%–100% and a specificity of 87%–100% for diagnosing knee ligament injuries in adults [114, 124].

2.5 Other Procedures

Methods for calculating bone age in children

In pediatric patients with open growth plates and anteromedial knee instability undergoing surgical treatment, determining "bone age" is an essential part of the evaluation. This allows the specialist to choose the optimal treatment strategy and minimize postoperative complications.

Comments. The essence of the method lies in using the Tanner-Whitehouse method (TW2.1975) [89] or the Greulich-Pyle bone age atlas method (W.W. Greulich and S.I. Pyle, 1959) [90]. The TW2 method is based on the precise measurement of each bone and expressing it as a numerical score; the sum of all scores gives the overall skeletal maturity index for the hand and wrist. The second method involves comparing the patient's radiograph with standard radiographs of healthy children of the corresponding sex, which are accepted as reference standards.

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

3.1 Conservative Treatment

Comments: conservative treatment may include restriction of strenuous physical activity, including joint offloading with crutches, physical therapy courses (ultrasound, cryotherapy, thigh muscle electrical stimulation, and magnetotherapy) that help reduce pain, relieve swelling, restore range of motion in the knee joint, and improve blood circulation; use of NSAIDs from group M01A (orally and topically); physical therapy exercises to restore range of motion in the knee joint and strengthen the quadriceps femoris; proprioceptive exercises; massage of periarticular muscles; intra-articular injections of hyaluronic acid preparations, and in more severe cases, glucocorticosteroids from group H02AB. Conservative treatment in patients with degenerative meniscus tears is just as effective as arthroscopic partial meniscectomy, relieving pain and improving knee function.

• Conservative treatment is not recommended for professional athletes and patients with high physical activity due to its ineffectiveness in the majority of cases [15].

GCR CLOE 4Grade of Recommendation C (Level of Evidence 4).

3.2 Surgical Treatment

Comments: The long-term clinical outcomes of this surgery are superior to those of arthrotomy, as the arthroscopic technique is less invasive and allows for early active rehabilitation.

- autografts;

- patellar tendon (BPTB);

- hamstring tendons (ST);

- peroneus longus tendon;

- allografts;

- synthetic materials [29-32].

RG CLE 5Recommendation Grade C (Level of Evidence 5).

Comments: currently, auto- (70%) or allografts (25%) are most commonly used. The choice is determined by the orthopedic surgeon's preference. Synthetic materials are used significantly less often (high cost, poor biocompatibility, low tensile strength, frequent synovitis).

• During the surgical intervention, it is recommended that all patients be guided by the principles reflected in the comments below [35, 149, 152].

GCR CLOCE 5Grade of Recommendation C (Level of Evidence 5)

Comments: The goal of the surgery is to restore the integrity of the ligamentous structures, resulting in joint stabilization.

Standard lower arthroscopic portals are used. The anterolateral portal is created using a narrow scalpel (45 degrees to the frontal plane of the knee) within the triangle bounded by the lateral edge of lig. patella (1 cm from it), the lateral femoral condyle, and the tibial plateau (1 cm above it). The anteromedial portal is created with a scalpel in a similar manner, but under the visual control of the arthroscope inserted into the joint cavity from the lateral side and along the guide needle, which is used to puncture the knee joint in the medial triangle beforehand. The latter portal is used to introduce microsurgical hand instruments and power tools.

The first stage involves diagnostic arthroscopy in the classic sequence:

- inspection of the upper compartments of the joint and the patellofemoral articulation with the knee extended;

- revision of the medial compartment with the knee extended and flexed, applying valgus stress to the lower leg and widening the medial joint space;

- inspection of the medial and then the intercondylar space while gradually flexing the joint up to 90 degrees;

- inspection of the lateral compartment with the knee joint flexed and varus stress applied to the lower leg, which widens the lateral joint space.

To increase diagnostic accuracy, the examination should be accompanied by additional manipulations: flexion-extension and rotational movements of the lower leg, palpation of the joint line and lateral displacements of the patella outward, probing of intra-articular elements with an arthroscopic probe, and eliciting the anterior drawer sign under visual control

The second stage consists of arthroscopic surgical interventions on the damaged elements of the knee joint and preparation of the graft bed. Ligament tears are often combined with injuries to the menisci and articular cartilage, and in the chronic stage, with their sequelae—osteoarthritis, local or diffuse synovitis, and hypertrophy of Hoffa's fat pad. Depending on the duration and type of injury, the ACL and/or PCL may be lysed and completely absent, appear as a dense rounded stump at the tibial attachment site, be frayed, or replaced by scar tissue. In the latter case, the ligament sags and is flaccid when probed, with the probe freely penetrating between the fibers. There are areas of induration at sites of scar changes, with damage to the synovial membrane covering the ligament. The lower leg translates anteriorly by more than 5 mm or is displaced posteriorly by mm under the influence of gravity. At this stage, endoscopic meniscectomies, partial synovectomies, chondroplasty of cartilage lesion sites using a shaver and burr are performed as needed, along with tunneling of subchondral bone plate areas, resection of ligament remnants, lateral parts of the hypertrophied Hoffa's fat pad, medial plica, and osteocartilaginous exostoses along the margins of the femoral condyles and intercondylar notch (notchplasty). The latter is an important step of this surgery. The minimum width of the notch should be about 20 mm to avoid impingement and damage to the autograft by the medial edge of the lateral femoral condyle, as well as to more accurately determine the center of the femoral tunnel.

The third stage of the surgery is endoscopic reconstruction of the ACL and/or PCL. If an autograft is used, this stage begins with graft harvesting (ST, BPTB, peroneus longus tendon), placing the autograft in 0.9% sodium chloride solution, and then tensioning it to the maximum on an arthroscopic tensioner (12% for 10-15 minutes).

There are many options for graft fixation; the choice depends on both the graft type (bone-tendon-bone or tendon-to-bone) and the orthopedic surgeon's preference in each specific case.

Fundamentally, there are two types of fixation:

- intra-articular fixation;

- extra-articular fixation.

Graft tunnels are created using specialized instrument sets available on the market.

The graft is secured using specialized fixation devices (ligament fixation device; orthopedic interference screw).

After securing the graft, its stability is tested.

All wounds are closed tightly in layers. The knee joint is drained for 24 hours using an active suction drain. Immobilization of the knee joint in a specialized brace that allows setting a specific flexion angle is advisable, thereby enabling early, controlled rehabilitation.

3.2.1 All-inside all-epiphyseal ACL reconstruction

Comments: Following arthroscopic inspection of the knee joint and diagnosis of an ACL tear, an incision is made along the anteromedial surface of the upper third of the lower leg in the projection of the pes anserinus. Upon reaching the semitendinosus tendon, it is harvested. The graft is then prepared. The tendon is passed through the loops of the suspension device and quadrupled. Afterward, the graft diameter is measured to select the optimal drill size, and the femoral tunnel is created. Using a drill guide under fluoroscopic control (C-arm), a fluted drill is introduced distal to the growth plate of the distal femoral physis. A suture loop is passed through for subsequent graft insertion into the tunnel. Using a drill guide under fluoroscopic control, a fluted drill is introduced proximal to the growth plate of the proximal tibial physis. The planned tunnel length is drilled. Using the pulled suture loop, the graft is pulled into the femoral tunnel, the correct position of the suspension button is verified, and it is then secured in the tibial tunnel. Subsequently, with the knee in extension, the button is fixed. Arthroscopic control of the position, tension, and absence of graft impingement is performed [92, 93].

3.3 Analgesic therapy

The fundamental principle of pain management currently is the implementation of the multimodal analgesia concept.

• For adequate pain relief, patients with knee ligament injuries are recommended to receive multimodal analgesia, which may include NSAIDs from the M01A group, paracetamol**, gabapentinoids, and immediate-release opioids, or monomodal analgesia if multimodal is contraindicated [37, 38, 117, 127].

GCR BLOE 1Grade of Recommendation B (Level of Evidence 1).

Comments: Multimodal analgesia refers to the combined use of various analgesics and pain management techniques in conjunction with non-pharmacological postoperative pain control methods in adults and children.

Multimodal analgesia is currently the method of choice for postoperative pain control. Its basis is the administration of combinations of non-opioid analgesics, specifically non-steroidal anti-inflammatory drugs (NSAIDs) from the M01A group and paracetamol**, which in patients with moderate to severe pain is combined with gabapentinoids, opioid analgesics (N02A Opioids) (if necessary), and regional analgesia techniques. The choice of a specific MMA regimen is determined by the invasiveness of the surgical procedure.

Analgesics with different mechanisms of action and non-pharmacological interventions aimed at targeting the peripheral and/or central parts of the nervous system [131]. This combination allows for more effective pain relief by potentiating the effects of various drugs, which in most cases leads to a reduced frequency of prescription and/or doses of opioid analgesics. Thus, MMA improves the risk profile of each drug while providing synergistic pain control using different classes of medications. Postoperative MMA may include psychotherapy, physical therapy, NSAIDs, paracetamol**, gabapentinoids, regional anesthesia (single-shot or continuous peripheral nerve catheter placement), local injections, and opioids [133].

In modern scientific literature, authors emphasize the use of the lowest effective doses of opioids for the shortest possible period, avoiding extended-release opioids. As an adjuvant during MMA in adult patients, a single intravenous dose of #dexamethasone** 1.25–20 mg can be administered prior to surgery (60 minutes before the incision), which provides a significant reduction in pain [132].

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.

Comments: NSAIDs are effective drugs for postoperative analgesia [40].

Comments: Paracetamol is an effective analgesic for relieving acute pain, and the frequency of side effects is comparable to placebo.

Comments: the combined use of NSAIDs and paracetamol** improves the quality of analgesia compared to the administration of each drug individually [47].

The prescription of NSAIDs (from the M01A group) to patients receiving patient-controlled analgesia (PCA) with opioids reduces the demand for opioids, as well as the incidence of nausea and vomiting [48, 49].

• If NSAIDs are insufficiently effective, it is recommended to use opioid analgesics (N02A Opioids) (Appendix A3.2) [73].

Level of Evidence BGrade of Recommendation 2Level of Evidence B (Grade of Recommendation 2)

Comments: Opioids remain widely used drugs for postoperative analgesia in most foreign and domestic clinics. The severity of the analgesic effect of µ-agonists should be similar provided they are used in equianalgesic dosages. In particular, the effect of 10 mg of morphine** should correspond to the effect of 20 mg of trimeperidine** or 100 mg of tramadol**. At the same time, there is individual variability in patient sensitivity to various opioid analgesics. Importantly, opioid analgesics provide only an antinociceptive effect, but do not prevent the development of hyperalgesia.

According to some experts, the postoperative administration of opioid analgesics is associated with an increase in the number of postoperative complications and also increases the cost of the patient's hospital stay. In addition to the long-known side effects of this drug group (respiratory depression, excessive sedation, gastrointestinal motility suppression, nausea, vomiting, pruritus), clinically significant complications such as opioid-induced hyperalgesia [54] and opioid analgesia-induced immunosuppression [55] have been actively discussed in recent years.

In the treatment of acute pain, no single opioid analgesic has advantages over another, although individual opioids may have specific benefits for certain patients [56].

• It is recommended for adult patients to use gabapentinoids as a single dose, 1–2 hours before surgery per os [69–71].

GCR BLOE 1Grade of Recommendation B (Level of Evidence 1).

Comment: The preoperative dose of gabapentin ranges from 300 to 900 mg, and pregabalin** from 75 to 300 mg. Some specialists prescribe gabapentinoids as a single dose, but most prolong their use. In the postoperative period, the recommended daily dose of gabapentin is 900–1200 mg, and pregabalin** is 150–300 mg. The duration of administration usually does not exceed 8–10 days [69–71]. The administration of gabapentinoids (gabapentin and pregabalin**) in the perioperative period reduces the intensity of postoperative pain and the need for opioid analgesics, decreases the frequency of nausea and vomiting, pruritus, and urinary hesitancy, but increases the risk of excessive sedation [69–71].

• For patients over 18 years of age, it is recommended to use regional analgesia for pain relief [74, 75].

GRL BLEL 3Grade of Recommendation B (Level of Evidence 3).

Comments: The most important task of MMA is to interrupt the afferent stream of nociceptive stimuli from peripheral pain receptors in organs and tissues to the segmental structures of the central nervous system (dorsal horns of the spinal cord). This task can be successfully solved using various regional analgesia (RA) techniques.

• For patients over 18 years of age, continuous peripheral nerve and plexus blockades are recommended for pain relief [137].

GCR CLOCE 4Grade of Recommendation C (Level of Evidence 4)

Comments: Indications for continuous peripheral nerve blocks: prolonged and traumatic interventions on the upper and lower limbs and trunk requiring analgesia for more than 24 hours, as well as supporting "fast-track" protocols, and prolonged peripheral blocks with local anesthetics in situations where the need for analgesia exceeds the duration of their single injection effect [75].

To provide prolonged (48–72 hours) postoperative analgesia and carry out rehabilitation measures, it is advisable to use nerve catheterization techniques. Nerve catheterizations should preferably be performed under ultrasound guidance, or as a last resort, using a electroneurostimulator. Blockade options depend on the surgical site (Appendix A3.3).

For isolated nerve blocks (femoral, sciatic, etc.) and plexuses (brachial, lumbar), an infusion of a 0.2% local anesthetic solution (ropivacaine**, levobupivacaine**) is used via elastomeric pumps or a syringe driver at a rate of 4–6 ml/h.

For interfascial blocks (fascia iliaca, TAP block, etc.), intermittent administration of a local anesthetic (ropivacaine**, levobupivacaine**) is preferred.

3.4 Surgical antibiotic prophylaxis

• In the surgical treatment of patients with anterior cruciate ligament (ACL) tears, it is recommended to perform surgical antibiotic prophylaxis (SAP) of surgical site infections by a single preoperative administration of an antibacterial drug to reduce the risk of infectious complications [84–86].

GCR CLEL 5Level of recommendation evidence C (level of data reliability 5).

Comments. In accordance with international clinical guidelines for the prevention of surgical site infections [86, 85], the goal 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; and for "clean" surgical wounds involving the placement of orthopedic implants and metal hardware. For infected ("dirty") wounds, SAP is not indicated; therapeutic antibiotic treatment is performed instead.

• In patients with ACL tears, it is recommended to use first- and second-generation cephalosporins (cefazolin**, cefuroxime**) as the primary drugs for surgical antibiotic prophylaxis in traumatology and orthopedic surgeries, and as an alternative in case of beta-lactam allergy—glycopeptide antibiotics (vancomycin**), lincosamides (#clindamycin**) [85].

GCR CLEL 5Level of recommendation evidence C (level of data reliability 5).

Comments. For patients with an unremarkable allergy history and no significant risk factors for methicillin-resistant staphylococci carriage, 1st and 2nd generation cephalosporins (cefazolin**, cefuroxime**) are used for surgical site infection (SSI) prophylaxis, administered intravenously 30 to 60 minutes prior to skin incision. In case of beta-lactam allergy, a combination of vancomycin** with one of the fluoroquinolones (ciprofloxacin**, #levofloxacin**), administered over at least 60 minutes starting 2 hours prior to the incision, or #clindamycin** should be prescribed. In the presence of significant risk factors for methicillin-resistant staphylococci (MRS) carriage, the SSI prophylaxis regimen must include an antibiotic with anti-MRS activity (vancomycin**). In most cases, a single preoperative dose of the antibiotic is sufficient for effective prophylaxis. For prolonged procedures or massive blood loss, an additional intraoperative dose of the antibiotic should be administered (the estimated time for intraoperative administration is 2 half-lives after the preoperative dose). Administration of the antibiotic after wound closure in the operating room is inappropriate even in the presence of established drains.

Single doses of core antibacterial drugs for SSI prophylaxis in traumatology and orthopedic surgery: cefazolin** 2 g (for patients weighing ≥120 kg – 3 g), cefuroxime** 1.5 g, #clindamycin** 900 mg [85], vancomycin** 15 mg/kg as a slow intravenous infusion [85], ciprofloxacin** 400 mg [85], #levofloxacin** 500 mg [85]

Single doses for children should be calculated based on actual body weight: cefazolin** 30 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 is contraindicated due to the risk of arthropathy [85].

3.5 Prophylaxis of venous thromboembolic complications

Comments: To assess the risk of VTE before surgery, it is advisable to use the 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 exercise (physiotherapy).

All patients with restricted physical activity (mobility), regardless of the VTE risk level, are recommended to undergo mechanical VTE prophylaxis [119]. All patients with a moderate or high risk of VTE are recommended to receive pharmacological VTE prophylaxis, typically until normal or expected physical activity is restored.

Pharmacological VTE prophylaxis in the preoperative period is performed with unfractionated heparin (UFH) from group B01AB or, preferably, low-molecular-weight heparins (LMWHs) from group B01AB (Appendices A3.5, A3.6). Vitamin K antagonists monitored by INR (international normalized ratio) may also be used [118].

For pediatric patients, LMWHs from group B01AB are preferred [145, 146], but currently in Russia the use of all LMWHs is contraindicated in children, therefore their prescription is only possible by decision of a medical commission ("off label" use). Some foreign guidelines mention the use of direct oral anticoagulants (rivaroxaban**) for VTE prophylaxis in children [140], however, there is currently insufficient clinical evidence regarding their efficacy and safety in this patient population [144, 141].

To make a decision on pharmacological VTE prophylaxis, consultation with a pediatrician or hematologist experienced in treating thrombosis in children is recommended. When prescribing anticoagulants to children, it is advisable to monitor complete blood count parameters within 48 hours after starting treatment with enoxaparin or heparin [142]. According to indications, the anti-Xa level should be determined 4 to 6 hours after administration of enoxaparin sodium** (target anti-Xa level 0.1–0.3 IU/mL). Routine monitoring of anti-Xa levels is not recommended [147]. When prescribing anticoagulants to children, the glomerular filtration rate is calculated using the simplified Schwartz formula (http://nephron.com/peds_nic.cgi).

• Patients requiring arthroscopic surgery are not recommended routine VTE prophylaxis in the absence of additional VTE risk factors and if tourniquet time is less than 45 minutes and anesthesia time is less than 90 minutes [119].

GCR CLEL 5Level of recommendation evidence C (level of data reliability 5).

• In cases where arthroscopy is performed using a tourniquet for 45 minutes or more, with general anesthesia lasting more than 90 minutes, or in patients at high risk for VTE, it is advisable to consider administering LMWHs 6–12 hours postoperatively, extending the thromboprophylaxis course for up to 10–14 days [119].

Grate BLEL 2Level of recommendation persuasiveness B (level of evidentiary reliability 2).

3.6 Nutritional Therapy

Specific diet therapy has not been developed.

4. Medical Rehabilitation and Sanatorium-Resort Treatment

Additional studies, ideally randomized controlled trials or comparable designs, are required before clinical guidelines for the treatment and rehabilitation of anterior cruciate ligament injuries can be developed [1, 3]. These guidelines are based on orthopedic knowledge of ligamentous apparatus repair and the mechanisms of action of medical rehabilitation methods and tools.

Comments: for knee joint immobilization, a knee immobilizer or plaster splint is applied. A more modern fixation method is the use of a functional brace for up to 6–8 weeks [104, 105].

The PRM/exercise therapy physician draws up a rehabilitation program (patient guide) with recommendations on activity regimen and physical exercises.

Prescribed:

- elevation of the limb,

- isometric contraction of thigh and lower leg muscles,

- active movements in the ankle and hip joints,

- walking with additional support using crutches.

When using a functional orthosis, which allows for complete anteroposterior joint stabilization while preserving range of motion throughout the treatment period, the starting range of motion in the knee joint is set at 20 degrees. Subsequently, the range of motion in the knee joint within the orthosis is increased to 90 degrees [98, 104]. The duration of this period is determined in consultation with the traumatologist and is up to 6–8 weeks.

Comments: after the removal of immobilization, the PRM physician / exercise therapy doctor draws up an individual rehabilitation program in accordance with the existing functional impairments. The following are prescribed:

1. To restore knee flexion:

- assisted dynamic exercises,

- positioning therapy (postural correction),

- exercises in water (hydrotherapy / remedial gymnastics in the pool),

- robot-assisted mechanotherapy for joint diseases and injuries

2. To improve blood circulation in the limb and normalize muscle tone:

- pressotherapy (A17.30.009 Barotherapy – limb pressotherapy, pneumatic compression)

- manual and/or underwater leg massage (therapeutic underwater jet massage, knee joint massage) [94, 100, 101].

Upon reaching 90 degrees of knee flexion, following a repeat consultation with the PRM physician / exercise therapy doctor, the following are prescribed:

3. To restore thigh muscle strength and endurance:

- dynamic exercises with resistance and weights,

- robot-assisted mechanotherapy for diseases and injuries

- exercise therapy using apparatus and exercise machines (A19.04.001.023)

- biofeedback training based on ground reaction force and podographic indicators (A19.04.001.015 and A19.04.001.016)

- biofeedback-assisted exercise therapy for joint diseases and injuries (A19.04.001.012)

- restoration of the proper gait stereotype [93, 97, 100, 111].

Exercise therapy modalities are prescribed in combination with physical therapy: local cryotherapy, electroanalgesia (A17.04.001), and ultrasound therapy (A17.30.034) as indicated to reduce edema, pain, and tension in the capsular-ligamentous structures, followed by electrical stimulation (A17.02.001) of the thigh muscles [93, 103, 106].

Comments: immediately after surgery, the PRM/exercise therapy physician draws up an individual rehabilitation program prescribing:

- positioning treatment (postural correction),

- local cryotherapy,

- electroanalgesia (transcutaneous electrical nerve stimulation (TENS)),

- pulsed electromagnetic field,

- isometric and ideomotor exercises,

- general tonic exercises for healthy limbs.

Immobilization in a functional brace is carried out for up to five days in a full extension position. Thereafter, the range of passive motion in the knee joint is gradually increased by 10 degrees per day up to an angle of 90 degrees. The total duration of immobilization is up to 3–5 weeks. After 3–4 weeks, a further increase in the flexion angle is recommended.

On day 3, walking with crutches without bearing weight on the affected leg is permitted in the brace, and on days 4–5 the patient is discharged to the home rehabilitation stage [93, 99, 108, 109].

The issue of using a brace or knee orthosis after ligamentoplasty is debatable; however, it has been noted that from the perspective of improving the patient's quality of life, immobilization is important as a method of reducing postoperative pain [94, 104, 105].

The PRM/exercise therapy physician prepares a guide for home rehabilitation prescribing therapeutic exercises and rational motor activity. Equipped with a further rehabilitation program, the patient is able to undergo rehabilitation at home independently, receiving outpatient consultations from the PRM/exercise therapy physician to adjust the treatment [108]. There is no consensus on this issue, and a number of authors believe that home rehabilitation will not lead to a significant improvement in outcomes and will hinder the return to sports [98, 109, 110].

Comments: after 3 weeks, the brace is removed. The PRM/exercise therapy physician draws up an individual rehabilitation program (weeks 3–4) prescribing:

1. To improve blood circulation in the leg:

- apparatus-based local cryotherapy

- pulsed electromagnetic field,

- barotherapy – limb pressure therapy, pneumatic compression,

- application of a low-frequency pulsed electrostatic field [94, 96, 99, 100, 102-104, 107, 111, 112].

2. To improve knee joint mobility:

- mechanotherapy using electrically or pneumatically powered devices for joint diseases and injuries,

- free dynamic exercises for adjacent joints,

- assisted dynamic exercises with self-help or pulley systems;

- positioning treatment for the knee joint.

The range of motion in the knee joint should remain within 180 degrees of extension and 90 degrees of flexion for up to 3 months.

Two weeks after the follow-up consultation with the PRM/exercise therapy physician, a rehabilitation program (weeks 4–6) is drawn up prescribing:

- dynamic exercises with graded resistance and weights to improve muscle tone and strength [113],

- medical leg massage [102],

- thigh muscle electrical stimulation,

- hydrokinetotherapy for joint diseases and injuries, physical exercises in water, and therapeutic swimming.

Three months after surgery, restoration of the full range of motion in the joint is permitted.

The PRM/exercise therapy physician prescribes an individual rehabilitation program (weeks 7–12) utilizing:

1. To restore knee joint mobility:

- mechanotherapy using electrically or pneumatically powered devices for joint diseases and injuries, - robotic mechanotherapy

- hydrokinetotherapy for joint diseases and injuries, physical exercises in water, and therapeutic swimming.

- positioning treatment (corrective positioning packs),

- medical leg massage and therapeutic underwater shower-massage,

- ultrasound therapy or drug ultraphonophoresis – application of sinusoidal modulated currents and interference currents.

2. Restoration of joint mobility is carried out in parallel with strengthening the knee stabilizer muscles, prescribing:

- thigh muscle electrical stimulation,

- dynamic exercises with resistance and weights,

- static exercises,

- biofeedback training based on ground reaction force and podographic parameters (A19.04.001.015 and A19.04.001.016),

- therapeutic physical training with biofeedback for joint diseases and injuries (A19.04.001.012),

- normalization of the gait stereotype,

- gait training.

Ligament regeneration takes up to 6 months, after which the issue of returning to sports is considered. As indicated, between 3 and 6 months, repeat outpatient rehabilitation under the recovery period program is recommended, prescribing physical exercises with increasing load, training on exercise machines and mechanical apparatus, proprioception and balance training, and gait training.

5. Prevention and Dispensary Observation

6. Organization of Medical Care

Indications for hospital admission to a medical organization:

1) ineffectiveness of conservative treatment;

2) presence of indications for surgical correction.

Indications for discharging a patient from a medical organization:

1) completion of the rehabilitation course;

2) absence of surgical complications;

7. Additional Information

None.

Criteria for Evaluating the Quality of Medical Care

References

Appendix A1. Working Group Composition

1. Gerasimov S.A., Head of Traumatology and Orthopedics Department No. 1, University Clinic of the Privolzhskaya Research Medical University of the Russian Ministry of Health, member ofator.

2. Geroeva I.B., MD, DSc, Professor, National Medical Research Center of Traumatology and Orthopedics named after N.N. Priorov of the Russian Ministry of Health, Moscow.

3. Gorbatyuk D.S., Orthopedic Trauma Surgeon, Department of Care Organization, Analysis and Strategic Development of the Traumatology and Orthopedic Service, Directorate for the Implementation of Functions of the National Medical Research Center, National Priorov Medical Research Center of Traumatology and Orthopedics of the Russian Ministry of Health.

4. Zykin A.A., Candidate of Medical Sciences, Head of Traumatology and Orthopedics Department No. 2, Privolzhskaya Research Medical University of the Russian Ministry of Health, Nizhny Novgorod, member of ator.

5. Kleimenova E.B., MD, DSc, Professor, National Medical Research Center of Traumatology and Orthopedics named after N.N. Priorov of the Russian Ministry of Health, Moscow.

6. Korolev S.B., Doctor of Medical Sciences, Professor, Privolzhskaya Research Medical University of the Russian Ministry of Health, Nizhny Novgorod.

7. Korytkin A.A., Candidate of Medical Sciences, Novosibirsk Research Institute of Traumatology and Orthopedics named after Ya.L. Tsivyan of the Russian Ministry of Health, member of ator.

8. Nazarenko A.G., MD, Professor of RAS, Director of the Priorov National Medical Research Center of Traumatology and Orthopedics of the Ministry of Health of Russia, Moscow, Vice President of ATOR.

9. Otdelenov V.A., PhD, National Medical Research Center of Traumatology and Orthopedics named after N.N. Priorov of the Russian Ministry of Health, Moscow.

10. Ivanov K.A., Orthopedic Trauma Surgeon, National Priorov Medical Research Center of Traumatology and Orthopedics of the Russian Ministry of Health, Moscow.

11. Ivanov Ya.A., Orthopedic Trauma Surgeon, Department of Pediatric Traumatology, National Priorov Medical Research Center of Traumatology and Orthopedics of the Russian Ministry of Health, Moscow.

12. Sadykov I.F., Assistant, Department of Rehabilitology and Sports Medicine, Kazan State Medical Academy - branch of the Russian Medical Academy of Continuous Professional Education of the Russian Ministry of Health.

Conflict of interest: the working group members declare no conflict of interest regarding the development of this clinical guideline.

Appendix A2. Methodology for Developing Clinical Guidelines

Target audience for these clinical guidelines:

1. Trauma and orthopedic surgeons

2. Surgeons

3. Pediatric surgeons

4. General practitioners

5. Medical rehabilitation physicians

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. Levels of Evidence (LoE) grading scale for diagnostic methods (diagnostic interventions)

Table 2. Scale for grading levels of evidence certainty (LEC) for prevention, treatment, and rehabilitation methods (preventive, therapeutic, and rehabilitative interventions)

Table 3. Scale for grading grades of recommendation (GR) 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

Appendix A3.1. Doses of paracetamol and non-steroidal anti-inflammatory drugs recommended for postoperative analgesia (in accordance with drug instructions for use) in adults.

Appendix A3.2. Doses of opioid analgesics recommended for postoperative analgesia (in accordance with drug instructions for use) in adults

Appendix A3.3. Choice of block depending on the surgical site

Appendix A3.4. Recommendations for postoperative analgesia in children

¹ In children under 12 years of age, morphine** is the preferred opioid analgesic when necessary, as the use of tramadol** is associated with a high risk of adverse reactions [127, 128].

² Not recommended for use in children, as its metabolite accumulates in the body and provokes seizures upon repeated administration [129].

Appendix A3.5 Recommended intervals between prophylactic anticoagulant administration and neuraxial interventions in adults [148]

Time intervals between neuraxial intervention and anticoagulant administration are presented in accordance with the European Guidelines on Perioperative Venous Thromboembolism Prophylaxis [148].

Appendix A3.6 Recommended dosing regimen of low molecular weight heparins for high-risk VTE prophylaxis in conservative treatment and orthopedic surgery in adult patients at high risk of VTE

Appendix B. Physician Action Algorithms

Appendix C. Patient Information

Ligamentous apparatus injury is a pathological condition characterized by the complete damage (rupture) of one or more ligaments of the knee joint. The primary complaint is knee joint instability.

The diagnosis of ligament injury is established based on examinations—MRI, radiography of the knee joint—but can be definitively confirmed by a physician following a physical examination.

Conservative treatment has low efficacy, and in cases of complete ACL tears, the question of surgical intervention inevitably arises.

Ligament grafts can be either allografts or the patient's own tendons (BTB, ST, fibularis longus tendon). Using fixation devices, the ACL graft is secured within the bone tunnels (tibial and femoral).

In the ward immediately after surgery, the limb should be elevated on a Böhler splint, with local cold applied to the wound. Analgesics are prescribed based on the severity of the pain syndrome. To prevent infectious complications, broad-spectrum antibacterial agents are prescribed for at least 3 days. From the first days, isometric gymnastics and electrical stimulation of the limb muscles are prescribed (10-14 sessions). Thermal procedures (ultrahigh-frequency and super-high-frequency electromagnetic fields, paraffin, ozokerite; 10-14 sessions) should be applied after the first 2-3 weeks. If complications arise, appropriate complex treatment is performed. Immobilization in a functional orthosis for up to five days in the position of full extension; from days 5-7, the range of passive motion in the knee joint is increased to 20-30 degrees. Total immobilization duration is up to 8 weeks, with a gradual increase of the flexion angle in the operated joint by up to 5 degrees per week. Isometric contraction of the quadriceps femoris muscle. Electrical stimulation of the thigh muscles starting from the 10th postoperative day in subthreshold contraction mode (10-14 sessions). Permission to walk using crutches with partial weight-bearing on the operated limb from the 2nd-3rd postoperative day. Prolonged standing on the feet should be avoided. The average hospital stay after surgery is 3-5 days. The duration of temporary disability depends on the scope and complexity of the surgical intervention, averaging 3-5 months. Sports activities can be resumed only under medical supervision and no earlier than 6-12 months later.

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

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

Russian title: Caprini Individual Risk Assessment Scale for Venous Thromboembolism

Original title: 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 risk stratification of postoperative venous thromboembolism in the high-risk group. Pirogov Russian Journal of Surgery. 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 over 25 kg/m2

Minor surgery

Sepsis (within 1 month)

Serious pulmonary disease (including pneumonia within 1 month)

Oral contraceptive use, hormone replacement therapy

Pregnancy and postpartum period (up to 1 month)

History of unexplained stillbirths, spontaneous abortions (≥3),

Premature birth with preeclampsia or intrauterine growth restriction

Acute myocardial infarction

Chronic heart failure (within 1 month)

Bed rest in a non-surgical patient

History of inflammatory bowel disease

Major surgery within the past 1 month

Chronic obstructive pulmonary disease

2 points

Age 61-74 years

Arthroscopic surgery

Malignant neoplasm105

Laparoscopic surgery (duration > 45 min)

Bed rest > 72 h

Limb immobilization (within 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 point;

• moderate risk: 2 points;

• high risk: 3–4 points;

• very high risk: 5 points or more