Revision and re-revision after mobile- and fixed-bearing lateral unicompartmental knee arthroplasty

BACKGROUND: Limited information is available about revision after lateral unicompartmental knee arthroplasty (UKA) due to infrequency of this procedure. The purpose of this study is to examine reason for failure, time to failure, patient characteristics, type of revision and re-revision surgeries after failed mobile- and fixed-bearing lateral UKA. METHODS: In this single centre study, a total of 43 patients who underwent a revision surgery between 2010 and 2024 after mobile- and fixed-bearing lateral UKA implantation were analyzed. Demographic information, time to revision surgery, reason for failure, type of revision and re-revision surgery of these patients were evaluated. RESULTS: In revision after mobile-bearing lateral UKA group with 20 patients, progression of osteoarthritis (OA) and bearing dislocation were the leading reasons for revision. In 13 cases, conversion to total knee arthroplasty (TKA), in four cases conversion to fixed-bearing component and in three cases bearing exchange were performed after a failed mobile-bearing lateral UKA. After revision, five patients underwent a re-revision surgery. In revision after fixed-bearing lateral UKA group with 23 patients, progression of OA was the leading reason for revision. In 20 cases, conversion to TKA, in two cases conversion to TKA with augments and in one case conversion to Vanguard 360 knee revision system with augments were performed. After revision to TKA, one patient underwent a re-revision surgery. CONCLUSIONS: TKA without augments could be used in 94% of cases, if revision to TKA is performed. Bearing exchange or revision to fixed-bearing lateral UKA resulted in a high re-revision rate of 57%, so alternative revision strategies should be considered after a failed mobile-bearing lateral UKA.