High-Flexion Total Knee Arthroplasty Using NexGen LPS-Flex System: Minimum 5-year Follow-up Results

ABSTRACT

PURPOSE: This study is to report clinical and radiological results of high-flexion total knee arthroplasty (TKA) using NexGen LPS-flex system at a minimum 5-year follow-up, and to analyze the implant survivorship based on the results. MATERIALS AND METHODS: A total of 80 patients (118 knees) who underwent patellar preserving TKA using NexGen LPS-flex implant between February 2007 and February 2008 and could be followed for minimum 5 years were reviewed. The range of motion (ROM), hip-knee-ankle angle, Knee Society Knee score (KSKS), and Knee Society Function score (KSFS) were assessed preoperatively and at the last follow-up and analyzed. Implant position of the femoral and tibial components on the immediate postoperative and last follow-up X-rays were compared. RESULTS: The mean ROM was 110.2degrees+/-14.5degrees (range, 60degrees to 140degrees) preoperatively and 132.4degrees+/-5.2degrees (range, 90degrees to 145degrees) at the last follow-up. KSKS was 36.9degrees+/-6.4degrees preoperatively and 94.2degrees+/-3.2degrees at the last follow-up. KSFS was 30.5degrees+/-5.7degrees preoperatively and 93.7degrees+/-4.1degrees at the last follow-up. There was no statistically significant change in the implant position measured as alpha, beta, gamma, and delta angles at the last follow-up compared to the immediate postoperative values. Radiolucent lines were observed in 13 knees (11%) on the last follow-up X-rays. Revision TKA was performed due to aseptic implant loosening in 1 knee (0.84%), and the survival rate at the 5th postoperative year was 99.2%. CONCLUSIONS: The clinical and radiological outcomes of high-flexion TKA using NexGen LPS-Flex implant design were satisfactory with 99.2% implant survival rate after 5 years of protected activities of daily living.