Bilateral, spontaneous and simultaneous rupture of the quadriceps tendon in chronic renal failure and secondary hyperparathyroidism. Report of five cases.

Bilateral and simultaneous rupture of the quadriceps tendon of the knee without significant trauma in five patients, two males and three females, with chronic renal failure and secondary hyperparathyroidism is reported. Ruptures of the extensor mechanism are relatively rare injuries. Unilateral rupture is more common. Bilateral, simultaneous and spontaneous rupture is a very rare condition and only eleven cases have been reported in patients with a number of systemic diseases. Two cases have also been described in healthy subjects. The following points contribute to the diagnosis of quadriceps tendon rupture: 1) sudden pain and inability to extend the knee, 2) a palpable defect above the patella, 3) lateral x-rays with technique for soft tissue, reveal a defect and anterior tilting of the proximal pole of the patella. Operative repair of the ruptured tendon was the treatment in all our cases and gave excellent results.