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

## TL;DR

A rare case of bifocal patellar tendon rupture after total knee arthroplasty is reported, highlighting the challenges in healing and the need for tendon reinforcement.

## Contribution

This case report presents a rare bifocal rupture of the patellar tendon following TKA and emphasizes the importance of tendon augmentation for healing.

## Key findings

- Bifocal rupture of the patellar tendon is rare, especially in older adults.
- Vascular disruption from surgical exposure weakens the extensor apparatus and impairs healing.
- Simple repair is inadequate; tendon augmentation is necessary for successful outcomes.

## Abstract

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.

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.

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.

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.

•Weakening of the extensor apparatus in the suites of the total knee arthroplasty is a dramatic complication.•Surgical exposure is incriminated in the interruption of the vascularization of the extensor apparatus, making it fragile and predisposing it to injuries such as patella fractures and ligament ruptures, and also affecting its ability to heal following an action of repair or reconstruction.•The damage of the vascularization of the extensor apparatus affect also its capacity to heal which explains the necessity of a plasty or a reinforcement•The bifocal rupture of the extensor apparatus is a rare entity, even more in the old population.

Weakening of the extensor apparatus in the suites of the total knee arthroplasty is a dramatic complication.

Surgical exposure is incriminated in the interruption of the vascularization of the extensor apparatus, making it fragile and predisposing it to injuries such as patella fractures and ligament ruptures, and also affecting its ability to heal following an action of repair or reconstruction.

The damage of the vascularization of the extensor apparatus affect also its capacity to heal which explains the necessity of a plasty or a reinforcement

The bifocal rupture of the extensor apparatus is a rare entity, even more in the old population.