Bifocal rupture of the patellar tendon in TKA: Case report and review of the literature.

INTRODUCTION AND IMPORTANCE: Rupture of the extensor apparatus is a serious complication that can occur in a prosthetic knee. Bifocal extensor ruptures are rare and even more uncommon in adults.

CASE PRESENTATION: We report the case of an obese, diabetic, and hypertensive patient who underwent total knee arthroplasty two weeks previously and was admitted following a fall from her height for a rupture of the patellar tendon with release of the sutures. An investigation revealed bifocal avulsion of the patellar tendon from its patellar and tibial insertion. The patient was treated with double lacing and anchoring at the patellar and tibial levels with wire cerclage.

CLINICAL DISCUSSION: Several factors contribute to tendon fragility: degenerative changes linked to age, general or local conditions, and surgical approaches for TKA. These abnormalities also affect the tendon's ability to heal and should suggest the inadequacy of simple repair without tendon augmentation using a plasty, an autograft, or an allograft.

CONCLUSION: The prognosis for patients with extensor tendon ruptures in the TKA (total knee arthroplasty) remains unclear, and in our case, this was exacerbated by the delay between prosthesis insertion and the incident and by the open nature of the lesion.