Increased risk of revision for high flexion total knee replacement with thicker tibial liners

• Published in: The bone & joint journal Vol. 96-B; no. 2; pp. 217 - 223
• Main Authors: Namba, R S, Inacio, M C S, Cafri, G
• Format: Journal Article
• Language: English
• Published: England 01.02.2014
• Subjects: Aged; Arthroplasty, Replacement, Knee - methods; Bone Transplantation - methods; Female; Follow-Up Studies; Humans; Knee Joint - physiopathology; Knee Joint - surgery; Knee Prosthesis; Male; Prosthesis Design; Range of Motion, Articular; Reoperation; Retrospective Studies; Risk Factors; Tibia - transplantation; Treatment Outcome; Total knee arthroplasty; TKA; Revision; High Flex; THR
• ISSN: 2049-4394; 2049-4408
• DOI: 10.1302/0301-620X.96B2.32625

The outcome of total knee replacement (TKR) using components designed to increase the range of flexion is not fully understood. The short- to mid-term risk of aseptic revision in high flexion TKR was evaluated. The endpoint of the study was aseptic revision and the following variables were investigated: implant design (high flexion vs non-high flexion), the thickness of the tibial insert (≤ 14 mm vs > 14 mm), cruciate ligament (posterior stabilised (PS) vs cruciate retaining), mobility (fixed vs rotating), and the manufacturer (Zimmer, Smith & Nephew and DePuy). Covariates included patient, implant, surgeon and hospital factors. Marginal Cox proportional hazard models were used. In a cohort of 64 000 TKRs, high flexion components were used in 8035 (12.5%). The high flexion knees with tibial liners of thickness > 14 mm had a density of revision of 1.45/100 years of observation, compared with 0.37/100 in non-high flexion TKR with liners ≤ 14 mm thick. Relative to a standard fixed PS TKR, the NexGen (Zimmer, Warsaw, Indiana) Gender Specific Female high flexion fixed PS TKR had an increased risk of revision (hazard ratio (HR) 2.27 (95% confidence interval (CI) 1.48 to 3.50)), an effect that was magnified when a thicker tibial insert was used (HR 8.10 (95% CI 4.41 to 14.89)). Surgeons should be cautious when choosing high flexion TKRs, particularly when thicker tibial liners might be required.