With the advent of aging, the number of patients with knee pain is gradually increasing. Of all these patients with joint pain, arthritis caused by rheumatism, rheumatoid and other specific pathogenic factors is not common, and the true cause of most patients is osteoarthritis.
Osteoarthritis was previously referred to as osteoarthrosis, hypertrophic arthritis, etc. Currently, osteoarthritis is defined as the interaction of various mechanical and biological factors that cause disorders in the synthesis and breakdown of articular cartilage cells, extracellular matrix, and subchondral bone, resulting in cartilage softening, fibrosis, ulcer formation, loss of articular cartilage, and joint lesions such as sclerosis of the subchondral bone, ivorization, bone redundancy, and subchondral bone cyst formation. The essence of osteoarthritis is that various physical and chemical factors cause damage or degenerative changes to the articular cartilage, which in turn leads to a series of complications and sequelae.
Factors in the pathogenesis of knee osteoarthritis.
Physical factors.
Obesity is a risk factor for knee osteoarthritis. Trauma to the knee joint can directly damage the articular cartilage. Long-term overload and overload sports can cause osteoarthritis, and manual laborers and athletes are prone to knee osteoarthritis. Congenital joint deformities and joint dysplasia are also risk factors for osteoarthritis.
Organismal factors.
The occurrence of osteoarthritis of the knee is related to the aging of the patient. The anabolic capacity of the aging joint cartilage decreases, resulting in a decrease in the elasticity of the cartilage, a decrease in flexibility, and a poor resistance to injury. The incidence of osteoarthritis of the knee is more common in women than in men, especially in post-menopausal women, and the ratio of male to female incidence is about 1:3. Some scholars have studied the occurrence of osteoarthritis as a genetic factor.
Clinical features of osteoarthritis of the knee.
Joint pain: Early in the course of the disease, patients experience knee pain after excessive activity, which can be relieved after rest. As the disease worsens, resting pain and nocturnal pain occur, which cannot be completely relieved by rest. Patients walk with a limp.
Joint stiffness: The knee joint feels stiff after waking up in the morning and is relieved after activity. The duration of each time is less than half an hour, while rheumatoid arthritis usually causes morning stiffness of more than half an hour.
Joint swelling: When osteoarthritis of the knee develops to a certain stage, synovitis will appear and fluid will accumulate in the joint cavity, resulting in joint swelling. Late stage osteoarthritis can lead to knee swelling, which affects the aesthetics and becomes a reason for patients to visit the hospital.
Joint deformity: In the later stages of osteoarthritis, patients can develop inversion or valgus deformity of the knee joint, which further aggravates joint pain. Due to the loss of knee function, quadriceps atrophy, thigh thinning and weakness can occur.
X-ray examination of knee osteoarthritis: X-ray examination is recommended by the World Health Organization (WHO) as the primary means of examining morphologic changes in osteoarthritis. Osteoarthritis of the knee does not change significantly in the early stages of the disease and only shows narrowing of the joint space when the articular cartilage becomes thin to a certain extent. The intercondylar ridge of the tibia and the formation of bony redundancy at the edge of the joint are characteristic early changes in knee osteoarthritis. As the disease progresses, the articular cartilage degenerates further and radiographs show asymmetric joint gap narrowing, subchondral bone sclerosis and cystic changes, extensive bone redundancy at the tibial intercondylar ridge and joint margins, and intra-articular free bodies, especially in the suprapatellar capsule. In the later stages of osteoarthritis, there is loss of joint space and inversion and valgus deformity of the knee joint.
The Kellgren-Lawrence grading method is the most widely used for grading knee osteoarthritis. There are five grades:
Grade 0: Normal radiographic appearance.
Grade 1: Spur-like bones with normal joint space.
Grade 2: Significant bony bulge and mild narrowing of the joint space.
Grade 3: Multiple bony bulges, joint space narrowing, subchondral bone sclerosis, and ivory.
Grade 4: Multiple bony bulges and intra-articular free bodies, severe narrowing or loss of joint space, subchondral osteosclerosis, ivory formation, and bone cyst formation. Patients may develop X-leg or O-leg.
In middle-aged and elderly patients with knee pain, a comprehensive medical history, clinical symptoms and signs, combined with knee x-ray examination. We effectively differentiate knee osteoarthritis from rheumatoid arthritis and knee osteoarthritis due to ankylosing spondylitis, and it is not difficult to make the diagnosis of knee osteoarthritis. The difficulty in osteoarthritis of the knee lies in clinical work, how to educate patients, how to have a clear understanding of the nature of its development, treatment options and social hazards. The difficulty lies in carrying out systematic treatment and how to delay its course and reduce the rate of disability.