Although osteoarthritis of the knee is closely related to synovitis of the knee, it cannot be fully equated. Synovitis of the knee in the elderly is often a pathological change secondary to osteoarthritis, can be present in all stages of osteoarthritis and is a risk factor for the progression of osteoarthritis.
In early osteoarthritis of the knee, symptoms of synovitis (joint pain, swelling and fluid accumulation) are the main manifestation. In contrast, advanced osteoarthritis has developed lesions of the cartilage or subchondral bone and is dominated by severe osteoarthritic symptoms (such as severe joint deformity, narrowing of the joint space and huge bone formation).