Osteoarthrosis of the knee joint (gonarthrosis)

The knee joint consists of three anatomical parts (compartments): a tibial-femoral (tibiofemoral) section having a medial and lateral region, and a patellar-femoral (patellofemoral) division. Each of these areas can be individually affected by osteoarthritis, or any combination of lesions is possible. The most common is the isolated osteoarthrosis of the knee in the medial Tibi-femoral section and the combined lesion of the medial Tibi-femoral and patellofemoral divisions.

On average, the medial tybiofemoral department is afflicted in 75%, the lateral tiobiofemoral in 26%, and the patellofemoral in 48% of cases.

The loss of articular cartilage is usually most pronounced in the lateral patellofemoral region and on the articular surface of the tibia in the tibiofemoral section, the site least covered with menisci. Given to arthroscopy and MRI, along with the lesion of articular cartilage with gonarthrosis, menisci are affected. Osteophytosis is most pronounced in the lateral tibiofemoral compartment, whereas the maximum destruction of the cartilage is usually detected in the medial.

Biomechanics of the knee joint is well studied. In the normal joint, the load axis passes through the center of the tibiofemoral section. However, when the movements, when the load on the tibiofemoral department is 2-3 times the mass of the body, the maximum load is on the medial part of the joint; when flexing the knee joint, the load on the patellofemoral part of it is 7-8 times greater than the body weight. Perhaps this explains the high incidence of the lesion is the medial tybiofemoral and patellofemoral parts of the knee joint. The development of gonarthrosis is facilitated by some physiological abnormalities of the knee joint - physiological genu varum, hypermobility of the joint, etc. Meniscatectomy and ligamentous apparatus damage disrupt the normal distribution of load on the knee joint, which is a predisposing factor to the development of secondary gonarthrosis.

Patients with osteoarthritis of the knee joint can be divided into two groups. The first group includes patients of young age, more often men, with isolated lesions of one, less often both knee joints, who have a history of trauma or surgery (for example, meniscectomy) at the knee joint. The second group includes middle-aged and elderly people, mostly women, who are noted for osteoarthritis of other localizations simultaneously, including hands; many patients in this group are obese.

The most important symptoms of gonarthrosis are joint pain during walking, prolonged standing and descending the stairs; crunching in joints during movements; local tenderness in palpation, mainly in the medial part of the joint along the joint space; painful restriction of flexion, and later also extension of the joint, marginal bony proliferation, atrophy of the quadriceps muscle of the thigh. The defeat of the medial part of the knee joint leads to the development of varus deformity. The rarely occurring lesion of the lateral part of the tibiofemoral joint can cause the formation of valgus deformity. In any type of lesion, osteoarthritis of the knee joint often shows signs of inflammation. This changes the nature of the pain: pain increases, there is "starting" pain, pain at rest, morning stiffness in the joint lasting up to 30 minutes. In the joint area there is a slight swelling, a local increase in skin temperature. Due to the presence of bone or cartilaginous fragments ("articular mouse") in the joint cavity, the patient with gonarthrosis may have symptoms of "blockade" of the joint (acute pain in the joint, depriving the patient of the opportunity to do any movement).

Factors associated with progression of gonarthrosis (according to Dieppe PA, 1995)

• Elderly age
• Female
• Excess body weight
• Generalized osteoarthritis (nodes of Geberden)
• Diet with insufficient amounts of antioxidants
• A diet with a vitamin D deficiency / low level of vitamin D in the blood plasma

The course of osteoarthritis of the knee is prolonged, chronic, progressive, with a slow increase in symptoms, often without pronounced exacerbations. In some patients, gonarthrosis can proceed stably both clinically and radically for many years. Periodically, there may be a spontaneous decrease in the severity of symptoms. Unlike coxarthrosis and osteoarthritis of the joints of the hands, spontaneous improvement (reverse development) of the radiographic signs of osteoarthritis occurs extremely rarely. Osteoarthritis of the knee joint often occurs with periods of "exacerbation", which usually accompanied by the appearance of effusion into the joint cavity and last for days / months, and improvements, or "remission". In some cases, the deterioration of the course of the disease occurs within a few weeks or months. This may be due to the development of joint instability or destruction of the subchondral bone. Sudden, almost instantaneous pain in the knee joint can mean the development of aseptic necrosis of the medial epiphysis of the femur - a rare but severe complication of osteoarthritis.

[1], [2]