Ruptures of the extensor mechanism of the knee joint.

The cases of thirty-four patients with thirty-six ruptures of the quadriceps tendon and of thirty-three patients with thirty-six ruptures of the patellar ligament were studied. The ruptures of the patellar ligament occurred in patients forty years old and younger, while the quadriceps tendon ruptures occurred in older patients. Twenty-eight ruptures (38 per cent) were misdiagnosed initially. When treated without delay, end-to-end suture was found to give a satisfactory repair of the ruptured quadriceps tendons and patellar ligaments, although supplemental external fixation was needed in the latter type of injury. A pins-and-wires technique was found to give the best results in delayed repairs of the patellar ligament, while a variety of repair techniques was used in delayed repairs of the quadriceps tendon. The results of immediate repair at both sites definitely were better than those of late repair.