Osteoarthritis of the hip joint (coxarthrosis)

Coxarthrosis is osteoarthrosis of the hip joint. Most often, the pathological process develops in the upper pole of the hip joint with superolateral displacement of the femoral head (about 60% of patients with coxarthrosis, men are more often affected than women). Less common is damage to the medial pole of the joint with medial displacement of the femoral head and protrusion of the acetabulum (about 25% of patients with coxarthrosis, women are more often affected than men). Concentric damage, in which the entire joint is affected, is the rarest type of coxarthrosis (about 15% of patients with coxarthrosis, women are more often affected than men). Extremely rare is damage to the posteroinferior part of the joint, which can only be detected on an X-ray in the lateral projection.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ]

What causes coxarthrosis?

Coxarthrosis usually affects people aged 40-60 years. The main predisposing factors to the development of osteoarthritis of the hip joint are its congenital dysplasia, Perthes disease, anomalies in the length of the lower limb, dysplasia of the acetabulum. Unilateral coxarthrosis is much more common than bilateral.

What are the symptoms of coxarthrosis?

The main symptom of coxarthrosis is pain when walking and putting weight on the leg in the thigh, buttock, groin, sometimes only in the knee joint, which significantly complicates diagnosis. Patients are bothered by stiffness in the affected joint after a period of rest; painful decrease in the range of motion, with the volume of internal rotation decreasing first, then external rotation and the angle of abduction of the leg. The functional ability of the patient decreases: it is difficult to bend over, put on socks, shoes, or lift something from the floor. In the most severe cases, crepitations can be heard (but not palpated) during movements in the joint. Pain over the lateral surface of the joint can be caused by secondary trochanteric bursitis. In the later stages, coxarthrosis is characterized by the appearance of lameness due to shortening of the leg due to migration of the femoral head, and with bilateral lesions - a "duck gait". Atrophy of the thigh and buttock muscles develops, characteristic “antalgic” (coxalgic) gait and the so-called Trendelenburg sign appear: when the patient tries to lean on the affected limb, the pelvis drops.

Coxarthrosis is the most severe form of osteoarthrosis. The course of the disease is chronic and progressive. The rate of disease progression varies. In most cases, patients who require surgical treatment have a relatively short history - from 3 to 36 months. With a rapidly progressing course of coxarthrosis, complete disability of the patient occurs within a few years, especially with bilateral lesions. According to LG Danielsson (1964), in some of the examined patients, the condition remained stable for 10 years or more. Coxarthrosis with concentric lesion of the hip joint and the hypertrophic variant has a more favorable prognosis. Cases of spontaneous regression of the disease have been described for coxarthrosis if surgical treatment was postponed.

Most often, coxarthrosis is complicated by bone tissue destruction. Other complications of coxarthrosis include aseptic necrosis of the femoral head, acetabular protrusion, and destruction of acetabular cysts. In some cases, rapidly progressing coxarthrosis can lead to an unusual picture - pronounced bone tissue destruction and a wide joint space. This type of coxarthrosis is called "analgesic hip joint" because it is associated with the use of painkillers. However, it can also develop in patients who do not take any or take few analgesics and NSAIDs.

Coxarthrosis may occur secondarily against the background of contralateral or ipsilateral gonarthrosis. Among the complications from periarticular structures, trochanteric bursitis most often develops.

Coxarthrosis: types

Coxarthrosis is radiologically divided into two types: hypertrophic coxarthrosis, in which the signs of an increased reparative response (osteophytes, subchondral sclerosis) predominate, and atrophic coxarthrosis, in which the signs of an increased reparative response are not expressed. Some authors describe a special form of rapidly progressing coxarthrosis, in which the narrowing of the joint space occurs over several months.

The study of joint biomechanics has demonstrated that the load on the hip joint consists of body weight load and hip adductor forces. The superior pole of the joint is the area through which the axis of body weight load passes, so the superior pole is the most vulnerable area.

According to some data (54 patients with coxarthrosis and 40 individuals without pathology of the musculoskeletal system were examined, the groups were comparable by age and gender), a decrease in the range of motion in the hip joint was associated with the severity of the clinical and radiological stage of the disease. However, not all types of movements were associated with the progression of coxarthrosis: thus, the highest correlation was noted for flexion (r = -0.84), abduction and internal rotation of the hip (r = -0.69 and r = -0.67, respectively), a weaker correlation - for external rotation (r = -0.40); no correlative relationship was found for adduction.

Consequently, a decrease in the range of motion in the hip joint (flexion, abduction and internal rotation of the hip) significantly correlates with the severity of the radiographic stage of the disease coxarthrosis.

In the late stages of coxarthrosis, significant changes in the synovial membrane and thickening of the joint capsule are detected. A study of material obtained during hip arthroplasty indicates that coxarthrosis often has small zones of aseptic necrosis of the femoral head.

[ 6 ], [ 7 ]