Peroneus Longus Tendon Graft in Extensor Mechanism Reconstruction After Total Knee Arthroplasty: A Viable Alternative

The rupture of the extensor mechanism following total knee arthroplasty (TKA) is a rare and severe complication that poses a significant challenge in knee surgery. The rupture can occur in the patellar or quadriceps tendons or due to patellar fractures, leading to substantial functional deficits. Risk factors include multiple prior surgeries, systemic conditions, as well as iatrogenic injuries. Reconstruction techniques range from autografts, allografts, and synthetic materials to local flaps, but none have shown exceptional results. This case report describes extensor mechanism reconstruction using a peroneus longus tendon graft in a patient. A 74-year-old active female patient was referred from a rural area to a knee surgery referral hospital with a history of progressive osteoarthritis in the left knee and underwent TKA. At her first post-surgical follow-up, she was diagnosed with an extensor mechanism rupture and referred to our institution, being admitted six weeks postoperatively. On initial assessment, she presented difficulty in fully extending the knee and patellar elevation. Extensor mechanism reconstruction was indicated, using an autograft from the peroneus longus tendon due to limited access to tissue banks and synthetic materials. The graft was fixed using anchors and an interference screw, resulting in stable patellar tracking. Postoperatively, the patient followed a rehabilitation protocol with the use of a brace and gradual weight-bearing and mobility. One year after surgery, she demonstrated an unassisted gait without a limp, with restored extensor mechanism competence and a range of motion of 0-120 degrees. Several techniques have been described for patellar tendon reconstruction following TKA, but the results remain unsatisfactory. Most techniques involve the use of allografts, which, although moderately effective, can lead to residual deficits and the need for ambulatory aids. Synthetic materials have gained popularity but face challenges such as cost and tissue reactions. The use of autografts, like the peroneus longus tendon, has shown promise due to its robustness and adaptability. This report highlights a successful case of extensor mechanism reconstruction using the peroneus longus tendon. The peroneus longus tendon graft offers a viable alternative for extensor mechanism reconstruction after TKA: minimizes costs, reduces risks of tissue rejection and cross-infection, and facilitates early rehabilitation.