Recurrent dislocation of a posterior-stabilized prosthesis: a series of three cases.

We report three cases of recurrent posterior dislocation of primary posterior-stabilized total knee replacements. In all of the cases, reduction was not possible under sedation alone, and general anaesthesia was needed to allow disengagement of the components and reduction of the dislocation. In addition, it was noted in all cases that the ability of the patients to flex their knee replacement excessively contributed to the instability. The design of the prosthesis, and issues of operative technique are discussed with reference to this serious complication.