Which lower extremity joint is most commonly affected by osteoarthritis?

The hip joint is the most commonly affected joint by osteoarthritis in the lower extremities due to its significant weight-bearing function and the stress it endures over a lifetime. As individuals age, the cartilage within the hip joint can degenerate, leading to pain, stiffness, and decreased mobility characteristic of osteoarthritis. The hip is a primary joint involved in daily activities such as walking, climbing stairs, and standing, making it particularly susceptible to wear and tear.

In contrast, while the ankle joint can also be affected by osteoarthritis, it is less frequently the primary site compared to the hip. The elbow and shoulder joints are part of the upper extremities and are less relevant in this context since the question pertains to lower extremity joints specifically. Therefore, the hip's involvement in weight-bearing activities and its biomechanical importance make it the joint most commonly associated with osteoarthritis in the lower extremities.