Lateral Collateral Ligament Reconstruction Using Semitendinosus Autograft for Lateral Instability Following Total Knee Replacement: A Prospective Case Series

Background: Instability following total knee replacement (TKR) is a major cause of patient dissatisfaction and revision surgery. Lateral instability caused by lateral collateral ligament (LCL) insufficiency is relatively uncommon but can significantly compromise knee stability and prosthetic longevity. When prosthetic components are well aligned and stable, ligament reconstruction may represent a joint-preserving alternative to revision arthroplasty. Aim: To evaluate the clinical and radiological outcomes of LCL reconstruction using semitendinosus autograft in patients presenting with lateral instability following total knee replacement. Methods: A prospective case series of 15 patients with symptomatic lateral instability following primary TKR was conducted. Patients underwent LCL reconstruction using semitendinosus autograft. Clinical and radiological outcomes were assessed using Knee Society Score and stress radiographs with a minimum follow-up of 6 months. Results: The mean Knee Society Score improved significantly from 56 ± 7 preoperatively to 84 ± 5 postoperatively (p < 0.001). Varus instability was corrected in 14 of 15 patients. Range of motion improved from 95？ ± 12？ to 105？ ± 10？ (p = 0.02). No major complications such as graft failure, infection, or peroneal nerve injury were observed. Conclusion: LCL reconstruction using semitendinosus autograft is an effective treatment option for managing lateral instability following TKR in patients with well-aligned prosthetic components. Ligament reconstruction may serve as a joint-preserving alternative in carefully selected patients with well-aligned and well-fixed prosthetic components. In the present study, reconstruction allowed preservation of implants in all cases during short-term follow-up; however, longer follow-up is required before concluding its role in avoiding revision arthroplasty.