LONG-TERM SURVIVORSHIP AND COMPLICATIONS IN REVISION TOTAL KNEE ARTHROPLASTY WITH A CONSTRAINED CONDYLAR KNEE IMPLANT: A MINIMUM TEN-YEAR FOLLOW-UP STUDY

The Legacy Constrained Condylar Knee (LCCK™) prosthesis is an implant option for revision total knee arthroplasty (TKA), particularly in cases requiring increased constraint due to ligamentous insufficiency and moderate bone loss. Long-term outcomes of LCCK implants are not well documented in the literature. This study aims to assess the survivorship and complications associated with LCCK implants over a minimum follow-up period of 10 years. We conducted a retrospective review of 345 revision TKA procedures using LCCK implants performed at our institution between 2001 to 2014. The cohort included 190 females (55%) and 155 males (45%), with a mean age of 69.3 years (SD, 9.7) and mean follow-up of 13.5 years (range, 10–23.3). The primary diagnosis before initial TKA was osteoarthritis in 279 patients (81%). Primary indications for revision included aseptic loosening (23.2%), infection (22.9%), malrotation/malalignment (14.2%), and instability (13%). Femoral and tibial augments were required in 238 and 62 cases respectively, with 25 patients requiring management of bone defects (15 femoral, 5 tibial, and 5 combined femoral and tibial). Kaplan-Meier survival analysis was performed with failure defined as revision for any cause and revision due to aseptic loosening. The survivorship for all-cause revision was 96.2% (95% CI: 94.2–98.2) at 2 years with 332 knees at risk and 95.1% (95% CI: 92.7–97.5) at 5 and 10 years with 328 and 315 knees at risk, respectively. Survivorship for aseptic loosening was 99.1% (95% CI: 98.1–100) at 2 years with 333 knees at risk and 98.5% (95% CI: 97.1–99.9) at 5 and 10 years with 327 and 314 knees at risk, respectively. Twenty-five complications occurred in 25 patients at a mean of 2.9 years (range, 0.16–9) post-revision, with 22 requiring surgical intervention. The most common complications requiring revision were infection (n=12, 54.5%) and aseptic loosening (n=7, 31.8%). Surgical management included revision TKA (n=7), irrigation and debridement with polyethylene exchange (n=4), two-stage revision (n=3), and above-knee amputation (n=2). LCCK implants demonstrate favourable long-term survivorship in revision TKA at minimum 10-year follow-up. These findings support the continued use of LCCK implants in revision TKA with appropriate patient selection and careful surgical technique.