Unhooking of GSB total knee during dislocation of the patella.

This is a case report of a special and undoubtedly rare complication occurring in a hinge joint with a moving instant center such as the GSB total knee joint. The preoperative situation, the history of the incident and the operative report are being described as well as a radiological follow-up. The mechanism of unhooking of the tibial shaft from its junction with the femoral stem during dislocation of the patella is being reconstructed.