This retrospective study investigated the midterm results of medial opening wedge high tibia osteotomy, with a monoplanar or a biplanar osteotomy using two types of implant system.
Osteotomies were performed on 241 knees (231 patients). The mean follow-up period was 6.0 years (SD 3.0, range 0.2-12.8 years). Two types of implant system were used, a precountered non-locking plate (PP) (n = 74) and a precountered locking plate (LP) (n = 167). A Kaplan-Meier cumulative survival curve and a Cox regression model were used to analyse and revise survival and risk factors.
Cumulative survival estimates for LP were 80% at 5 years, and 64% at 10 years (SE = 0.4, CI 95%: 9.0-10.5), and for PP, they were 68% at 5 years and 49% at 10 years (SE = 0.5, CI: 95% 6.3-8.2) (p = 0.024). The revision rate was 26% (44/167) for the LP group, and 47% (35/74) for the PP group (p = 0.001). Reoperations on LP osteotomies occurred for the tibial monoplanar cut and biplanar cut groups, in 19/52 (37%) and 25/167 (16%) osteotomies, respectively (p = 0.04). Our Cox regression model showed that PP had a higher risks (RR = 1.7; CI: 95% 1.1-2.6) of revision, when compared with LP (p = 0.026).
The risk of revision for any reason and that of early conversion to total knee arthroplasty (TKA) after high tibia osteotomy were significantly increased for PP, when compared with LP.