566 - Rare Case of Patellar Tendon Rupture after a Total Knee Arthroplasty: A Case Report

Case Diagnosis: Patellar-Tendon Rupture after a Total Knee Arthroplasty

Case Description: Patient is a 79 year old female with a past medical history of morbid obesity who presented for a left total knee arthroplasty due to severe osteoarthritis. Her surgical course was complicated by a left patellar-tendon rupture and underwent a left patellar-tendon repair followed by a long cylinder cast for six-weeks. Patient was admitted to inpatient rehabilitation for inability to ambulate more than 10feet with an unsteady-gait and decreased foot clearance. Repeat MRI two weeks later showed complete tear of the patellar-tendon at the anterior tibial-tuberosity insertion, with mild superior tendon retraction of approximately 0.3cm. Patient made significant gains with physical therapy and was able to ambulate 80feet with a rolling-walker. During this time, she was advised to allow for the healing and formation of scar tissue in the extensor mechanism and would be re-evaluated by orthopedics.

Discussions: Patellar-tendon rupture following total knee arthroplasty is a rare but severe complication, with reported prevalence rates ranging from 0.17% to 1%. Patellar-tendon rupture can occur during knee surgery, either intra-operatively due to fiber damage or postoperatively due to factors like trauma, compromised blood supply, weakened soft tissues, or infection. Treatments include immobilization, direct primary repair through sutures, staples, synthetic grafts, and allograft reconstruction of the extensor mechanism. However, there is no universally recommended method and outcomes are often poor. The choice of treatment depends on the patient's overall health, functional needs, the extent of tendon tear, the degree of functional impairment, and the availability of viable tissue for repair.

Conclusions: Patellar-tendon rupture following total knee arthroplasty is a severe and rare complication. This injury can result in substantial functional impairment for the patient and poses considerable challenges for treatment and recovery. It is important to note that patellar tendon repair still carries a high risk of complications.