Flexion Contracture and Ankylosis of the Knee

In general, articular cartilage wears away in the flexed position as OA progresses. If patients are not properly guided and treated during this period, they will continue to hold the knee in a flexed position to avoid pain, resulting in posterior osteophyte formation, contracture of the posterior capsule, shortening of the hamstrings, contracture of the collateral ligaments, and contracture of the PCL, which will complete flexion contracture. In RA, flexion contracture may occur rapidly due to the dissolution of articular cartilage with worsening arthritis.