Functional Outcome after Repair of a Post-Total Knee Replacement Quadriceps Rupture in a Morbidly Obese Patient: A Rare Case Report

INTRODUCTION: Quadriceps rupture after a total knee arthroplasty is a rare complication. In addition, morbid obesity confounds the early diagnosis of any loss of function of the extensor mechanism. Poor tendon quality, fraying, and retraction of the tendon pose a distinctive challenge while repair, predisposing it to failure. The literature is devoid of reports highlighting this complication in a morbidly obese patient and its subsequent successful management. CASE REPORT: Through this case, we report a morbidly obese 71-year-old who underwent an uneventful left sided total knee arthroplasty and suffered from an atraumatic quadriceps rupture on post-operative day 17. The diagnosis was confirmed on ultrasound followed by magnetic resonance imaging. An innovative technique of repair incorporating two, 5 mm suture anchors for fixing the ruptured quadriceps into the patella, and subsequent fortification of the repair was undertaken, followed by a guarded physiotherapy regimen. At 10 weeks post-repair, the patient started walking without any assistive device and achieved excellent clinical and functional outcome without any complications. CONCLUSION: Post-total knee arthroplasty quadriceps rupture is a rare but dangerous complication, even more so in a morbidly obese patient due to the inherent weakness of the muscles and tendons. Timely diagnosis and adequate repair using the innovative technique described in this study, along with a guarded physiotherapy regimen that can help in dealing with such complications successfully, as shown in this case.