Fatigue fractures of Thompson prostheses. A clinical and biomechanical study of revision procedures.
In four patients with fatigue fractures of Thompson prostheses, all had been in place for more than five years. All the patients were very active following the original operative procedure. Radiographs showed a varus position of the implant in three of the four patients, and the proximal fragment appeared loose; this was confirmed at revision operation. The distal fragment was rigidly held, and was only removed after the femoral shaft had been fenestrated. If a window had been cut in the shaft of the femur, the bone was considerably weakened. This clinical impression was confirmed by cadaver studies, which revealed that a lateral window weakens the femur more than an anterior window. For revision operations, replacement with a long-stemmed prosthesis is desirable. This protects the weakened segment of the femur, and provides sufficient strength for immediate weight-bearing.
D001696:Biomechanical Phenomena; D005264:Femoral Fractures / Q000209:etiology* / Q000503:physiopathology; D005269:Femur / Q000503:physiopathology; D006622:Hip Prosthesis; D006801:Humans; D011183:Postoperative Complications / Q000209:etiology; D011474:Prosthesis Design