Femoroacetabular impingement (FAI) and the labrum
Anatomic variations of the hip joint represent a continuum, and there is no clear boundary between normal and pathological states. Several types of impingement are distinguished:
- Cam impingement (Cam lesion): a cam-type deformity, more common in young men. A risk factor is a history of slipped capital femoral epiphysis leading to femoral neck retroversion.
- Pincer impingement (Pincer lesion): a pincer-type deformity, typical for middle-aged women. Associated with acetabular protrusion or deep acetabulum.
- Mixed type: the most common variant.
Labral tears often develop against the background of hip dysplasia. Treatment begins with conservative measures (rest, NSAIDs, physical therapy). If ineffective, surgery is indicated, with labral refixation yielding better outcomes than resection. Bony deformities should ideally be addressed simultaneously with labral repair.
Differential diagnosis and red flags
Hip or groin pain in young active patients is most often associated with extra-articular muscle and tendon injuries. However, other pathologies must also be ruled out:
- Snapping hip syndrome: mimics the mechanical pain of FAI.
- Bursitis (especially iliopectineal) and neuropathies (obturator or ilioinguinal nerve entrapment).
- Osteitis pubis and hip osteoarthritis (in the elderly).
A critical red flag is a femoral neck stress fracture. Its specific sign: pain occurs with weight-bearing and does not change with hip repositioning. This diagnosis must not be missed, especially in lean runners.
Hamstring injuries
The hamstrings (hamstrings) include the semitendinosus, semimembranosus, and biceps femoris muscles. They are responsible for hip extension, knee flexion, and deceleration during knee extension.
Injury typically occurs during an eccentric contraction (when the muscle lengthens under load). For example, during running, maximum tension is reached when the leg is swung forward.
Clinically, the injury presents with acute pain, swelling, and ecchymosis (appearing after a few hours). The patient shortens their stride to avoid putting tension on the muscles (short arc gait). Treatment is predominantly conservative, with surgery required only for bony avulsions or tendon retraction greater than 2 cm. It is important to differentiate this condition from lumbar spondylolisthesis.
Adductor and gluteal muscle pathologies
Adductor strain (Adductor strain) The adductor longus muscle (m. adductor longus) is most frequently affected. The injury is typical for soccer and hockey players, occurring during forced abduction during active contraction. It manifests as acute groin pain that worsens with passive abduction. Treatment is conservative, but the risk of recurrence is high.
Greater trochanteric pain syndrome Associated with tendinopathy of the gluteus medius and minimus muscles (m. gluteus medius et minimus) and inflammation of the trochanteric bursa. These muscles are critically important for keeping the pelvis horizontal (their weakness leads to a Trendelenburg gait). The syndrome is characteristic of individuals aged 50–70 (more often women). The main symptom is local tenderness over the greater trochanter. Treatment includes NSAIDs, physical therapy, corticosteroid injections, and shockwave therapy for resistant cases.
Briefly: answers to topical questions
What are the stages of gonarthrosis according to the Kellgren-Lawrence radiographic classification?
According to the Kellgren-Lawrence radiographic classification, the following early stages of osteoarthritis (including gonarthrosis) are distinguished:
- Stage 0 — no radiographic changes.
- Stage I — doubtful changes with absent or nearly imperceptible joint space narrowing, and small marginal osteophytes.
- Stage II — minimal changes characterized by slight joint space narrowing.
Information regarding subsequent stages is missing from the sources.
How does primary gonarthrosis differ from secondary gonarthrosis?
Primary gonarthrosis occurs without any apparent external causes. Secondary gonarthrosis is associated with factors noted in the anamnesis: traumatic injuries and joint surgeries, inflammatory arthritides, hemarthrosis, and other conditions disrupting the normal homeostasis of the joint's synovial environment.
What typical clinical symptoms characterize the advanced stage of gonarthrosis?
The late (advanced) stage of gonarthrosis is characterized by pronounced functional impairments and deformities.
- Pain syndrome — onset of nocturnal pain.
- Limited mobility — almost complete loss of joint mobility (only rocking movements remain), formation of flexion contracture.
- Deformity — pronounced lateral deformity of the limb axis (most commonly varus — genu varum).
- Muscular changes — weakness and atrophy of the quadriceps femoris.
- Instability — development of knee joint instability.
What are the absolute indications for total knee arthroplasty in gonarthrosis?
The sources do not single out specific "absolute" indications for total knee arthroplasty. The following indications for arthroplasty are listed: stage III gonarthrosis according to Kosinskaya's classification and stage III–IV gonarthrosis according to the Kellgren-Lawrence classification. In rare cases, arthroplasty is used at earlier stages if other treatment options have proven ineffective.
What is the essence of high tibial osteotomy in the treatment of gonarthrosis?
The essence of high tibial osteotomy (high tibial osteotomy) is the surgical transection and repositioning of the tibia (tibia).
- Correction — alignment of the lower extremity axis is corrected.
- Mechanism of action — the surgery redistributes weight-bearing load from the affected compartment to the healthier part of the joint.
- Goal — restoration of biomechanical balance in the knee joint in localized (single-compartment) arthritis.
Which drugs are used for intra-articular injection in the conservative treatment of gonarthrosis?
Hyaluronic acid-based synovial fluid substitutes are used for intra-articular injection in gonarthrosis. They are administered in the absence of pronounced synovitis, into a "dry" joint; the average duration of the effect is 4–6 months or longer. Intra-articular corticosteroids may also be used in osteoarthritis: they can reduce pain in some patients, but the effect is temporary.
How does the pain syndrome in gonarthrosis differ from the pain in rheumatoid arthritis of the knee joint?
In gonarthrosis, pain is mechanical in nature: it occurs or worsens with movement and load, and decreases or resolves at rest; in the early stages, it completely disappears after a period of rest. Rheumatoid arthritis is characterized by pain that worsens with movement and prolonged morning stiffness lasting more than 30 minutes.
Which lower extremity muscle groups need to be strengthened as part of physical therapy for gonarthrosis?
As part of physical therapy for gonarthrosis, the thigh and lower leg muscles need to be strengthened. The goals of physical exercises are to increase the range of motion in the joint, reduce pain, and expand the patient's physical activity. Weakness and atrophy of the quadriceps femoris are also frequently observed in knee osteoarthritis.
Class and exam questions
Cam deformity is more common in young men, while Pincer lesions are more common in middle-aged women. A combination of both is most frequently observed.
Cam deformity is more common in young men, while Pincer lesions are more common in middle-aged women. A combination of both is most frequently observed.
What are the red flags for hip pain?
Femoral neck stress fracture. Its main sign is activity-related pain that does not change with alterations in joint position.
What is the primary mechanism of hamstring injury?
Injury most often occurs during an eccentric contraction, when the muscle attempts to contract while biomechanically lengthening (for example, during deceleration of the leg while running).
What else to study on this topic
- Biomechanics of Trendelenburg gait and the role of the gluteal muscles
- Rehabilitation protocols following labral refixation
- MRI technique for evaluating myotendinous junction injuries
- Sports pubalgia and differential diagnosis of groin pain
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