Case: A 51-year-old woman, affected by end-stage renal disease, presented with 16-month-old ruptures of the right patellar tendon and the left quadriceps tendon. Since she had been nonambulatory for more than a year, the authors decided to perform a bilateral one-staged reconstruction with an Achilles tendon allograft on the right side and a full extensor mechanism allograft on the left side, achieving excellent clinical and functional results at 57 months' follow-up.
Conclusions: Bilateral spontaneous rupture of the extensor mechanism of the knee is a rare but dramatic occurrence. Allograft can be considered as a treatment option in case of chronic lesion or delayed reconstruction, with satisfactory midterm outcomes.