Dislocation of rotating-hinge knee prostheses with antidislocation mechanism.

At our institution, we have used Endo-Model prostheses (Waldermar Link GmbH & Co, Hamburg, Germany) for difficult knee reconstructions. These rotating-hinge prostheses have an antidislocation feature that prevents dislocation due to distraction disengagement. In a series of 192 consecutive prostheses, we have identified 2 cases of femorotibial dislocations. An increased flexion laxity allows excessive distraction and hence implant dislocation after antidislocation feature loosening. To our knowledge, there are no other reports in the literature regarding dislocation of a rotating-hinge knee prosthesis with antidislocation design.