Radiographic assessment of knee joint rotation.

A radiographic technique for measuring conjunct rotation at the knee joint is described. Conjunct rotation was demonstrated to occur over a greater range of values of flexion than conventionally believed. Rotation increased progressively as the knee extended, and was not confined to the last phase of extension. Consideration of such rotatory movement is relevant to the design of knee arthroplasties and also to possible mechanisms of non-bony injury of the knee.