Ruptures of the extensor mechanism of the knee joint. Clinical results and patellofemoral articulation.

The functional results of 28 cases of rupture of the quadriceps and patellar tendons are reported. Excellent or good results were noted in 15 of 18 quadriceps and 7 of 10 patellar tendons. Radiographic comparison with the opposite knee disclosed incongruences between the patella and the femoral groove in the tangential view and/or cranial-caudal position of the patella in the lateral view in 13 of the quadriceps tendon ruptures and seven of the patellar tendon ruptures. Patients with residual pain had patellofemoral incongruity but since two-thirds of the patients with incongruity were asymptomatic, incongruity alone may not be the cause of the symptoms. There was no positive correlation to muscular strength or range of movement. Nevertheless, exact adaptation of the patellar tendon and periarticular tissue seems necessary to obtain correct patello-femoral articulation. Reinforcement of the tendon with a wire cerclage is recommended to decrease the tension on the suture line and the consequent risk of a secondary rupture. In acute ruptures of the quadriceps tendon end-to-end sutures are sufficient.