What is the primary complication of a medially displaced patella in genu valgus?

The primary complication of a medially displaced patella in genu valgus is indeed impaired joint function. Genu valgus, or "knock-knees," leads to an alignment issue where the knees angle inward while the ankles remain spaced apart. This misalignment can cause the patella to track abnormally during movement, often leading it to shift medially.

When the patella is displaced medially, it can result in increased stress on the surrounding joint structures, including ligaments, tendons, and the cartilage that lines the joint surfaces. This abnormal tracking can lead to pain, swelling, and decreased range of motion, all of which significantly affect a person's ability to perform activities such as walking, running, and squatting. Over time, impaired joint function can lead to compensatory movement patterns that may further exacerbate musculoskeletal issues.

While other complications such as joint degeneration, soft tissue injury, and increased risk of fracture may occur as secondary consequences of chronic misalignment and impaired function, the most immediate and direct issue arising from a medially displaced patella in the context of genu valgus is the impairment of the joint's normal function. This condition often requires physical therapy interventions to restore alignment and improve muscle strength to enhance joint stability and function.