Normo-or slightly overcorrection show better results after medial closing wedge high tibial osteotomy

Purpose: The objectives of this study were to evaluate functional results, revision-free survival, and the influence of postoperative alignment on outcomes after MCWHTO.

Methods: This retrospective study included 27 MCWHTO operated on from 2009 to 2021. Radiographic measurements were performed pre- and postoperatively. The HKA (Hip-Knee-Ankle angle), MPTA (Medial Proximal Tibial angle), LDFA (Lateral Distal Femoral Angle), JLO (Joint Line Obliquity), and JLCA (Joint Line Convergence Angle) were evaluated. The Knee injury and Osteoarthritis Outcome Score (KOOS), the International Knee Society (IKS) Function and Knee Score, and the Subjective Knee Value (SKV) as well as revision-free survival were evaluated. Postoperative alignment and its influence on clinical outcomes were also analysed.

Results: The mean follow-up was 61.9 months ± 31.4 (13-124). The HKA, MPTA, and JLCA angles were decreased post-operatively (respectively, Δ = 5.9° ± 2.6, p < 0.001; Δ = 6.1° ± 3.2, p < 0.001 and Δ = 2.5° ± 1.9, p < 0.001). LDFA and JLO were unchanged, post-operatively (respectively, Δ = 0.1° ± 2.2, p = 0.93 and Δ = 1.2° ± 3.3, p = 0.23). Postoperative HKA correlated with knee IKS (R = - 0.15, p = 0.04) and function IKS (R = - 0.44, p = 0.03). Postoperative LDFA correlated with knee IKS(R = 0.8, p < 0.01). Patients with postoperative HKA ≤ 180° had better KOOS (Δ = 12.3, p = 0.04) and IKS function (Δ = 28.1, p < 0.01) than those with HKA > 180°.

Conclusion: Functional results and revision-free survival after MCWHTO are satisfactory when the deformity is located in the proximal tibia. The joint line obliquity is not significantly altered with small tibial correction and, obtaining an overall neutral or slightly varus alignment under the conditions of this study allowed an improvement in the postoperative clinical scores. The literature is still inconclusive on the ideal alignment for valgus deformities and larger series are needed to draw definitive conclusions.

Level of evidence: IV, case series.