High rate of tibial post-fracture in highly cross-linked polyethylene compared to conventional polyethylene in posterior-stabilized total knee arthroplasty at a minimum 12-year follow-up.

purposeThe purpose of this study was to assess tibial post-fracture between highly cross-linked polyethylene (HXPE) and conventional polyethylene inserts in consecutive posterior-stabilized (PS) total knee arthroplasty (TKA) over a minimum 12-year follow-up period.

methodsBetween January 2007 and June 2008, a consecutive series of 2446 primary TKAs was performed in 1478 patients at a single institution. The final cohort was classified into two groups (1559 in the HXPE group and 887 in the conventional group) based on the insert material used during the procedure.

resultsThe mean follow-up period was 13.1 years in the HXPE group and 13.4 years in the conventional group. All 16 cases of tibial post-fracture occurred in the HXPE group. This complication rate was 1.03%. The mean elapsed time from primary TKA to the diagnosis of post-fracture was 3.9 years (range 0.5-10.0 years). Ten cases required replacement with a thicker polyethylene insert, and six cases underwent tibial revision surgery. There were no cases of tibial post-fracture in the conventional group.

conclusionTibial post-fracture is not a rare complication in PS TKA with HXPE. Therefore, the possibility of a tibial post-fracture should be considered if newly developed pain, acute subluxation, effusion, patellar clunking, or instability occurs in patients treated with PS Scorpio knee system TKA using an HXPE insert. LEVEL OF EVIDENCE: IV.