Osteotomies for genu varum: Should we always correct at the tibia? A multicenter analysis of practices in France.

Abstract

Introduction: Tibial correction is often performed during a valgus-producing osteotomy for genu varum. However, overcorrection and the creation of a joint line obliquity (JLO) have been associated with unfavorable functional outcomes after high tibial osteotomy (HTO). The aims of this study were to analyze: 1) the corrections obtained after HTO; 2) the rationale behind the indication per the European Society for Sports Traumatology Surgery and Arthroscopy (ESSKA) recommendations; and 3) the correlation between the postoperative corrections obtained and functional outcomes.

Hypothesis: A significant number of patients who underwent an isolated HTO did not present an "ideal" theoretical indication based on the preoperative angles and correction targets to be performed.

Materials and methods: This multicenter study included 289 isolated HTOs. Demographic and morphometric data were anonymized and compiled in a database. Preoperative radiographic parameters were compared with the ESSKA consensus recommendations on osteotomies for genu varum. The consensus defined the "ideal" indication for performing an HTO as medial tibiofemoral compartment pain with significant tibial varus deformity (medial proximal tibial angle [MPTA]<85°), no significant femoral varus deformity (lateral distal femoral angle [LDFA]<90°), an expected postoperative obliquity of less than 5°, and a correction resulting in moderate tibial valgus (postoperative MPTA<94°). The incidence of patients with an "ideal" theoretical indication for isolated HTO and those with a theoretical indication not perfectly justified by the radiographic data and preoperative planning were recorded.

Results: Under the ESSKA consensus criteria, 25.3% (n=73) of isolated HTOs, 15.6% (n=45) of isolated femoral osteotomies, 9.3% (n=27) of double-level osteotomies, and 49.9% (n=144) of cases where no osteotomy was performed due to the lack of significant extra-articular tibial and/or femoral deformity were deemed justified. The presence of a preoperative femoral deformity and the absence of an "ideal" indication for HTO did not affect the postoperative Tegner Activity Scale or the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores (p>0.05). A high preoperative hip-knee-ankle (HKA) angle and MPTA, which indicated less varus, were associated with a greater risk of there being no "ideal" theoretical indication for an HTO (coefficient of determination [R²]=0.19 and R²=1, respectively; p<0.001).

Conclusion: This study showed that isolated HTOs in current practice were not justified in a significant number of patients, even though they could lead to tibial overcorrection and excessive JLO. This did not impact the functional results of this series, but it might complicate the performance of a secondary knee arthroplasty. Nevertheless, some young patients in this series underwent a salvage osteotomy outside the "ideal" indications of the European recommendations.

Level of evidence: IV; case series.