Sagittal alignment and patellofemoral consequences of open wedge high tibial osteotomy: a comparative radiological and gait analysis of supratubercle and distal tibial tuberosity techniques

The optimal osteotomy configuration in medial open-wedge high tibial osteotomy (OWHTO) remains debated. Descending biplanar and ascending biplanar techniques differ regarding biomechanical stability, risk of patellar height alteration, and hinge-related complications, yet high-quality comparative evidence integrating clinical, radiological, and gait-level functional outcomes is lacking. In this retrospective comparative cohort study, we reviewed 96 patients with medial compartment knee osteoarthritis who underwent supratubercle biplanar OWHTO (STB-OWHTO, n = 45) or distal tibial tuberosity osteotomy OWHTO (DTT-OWHTO). Clinical outcomes (Hospital for Special Surgery score), radiological parameters (weight-bearing line ratio, posterior tibial slope, and Caton–Deschamps index [CDI]), and gait biomechanics (spatiotemporal, kinematic, and kinetic variables, including the knee adduction moment) were retrospectively extracted from medical records and an institutional gait-analysis database preoperatively and at an early postoperative follow-up (mean duration, ~ 60 days). Baseline characteristics were comparable between the two groups. Both techniques yielded significant improvements in the HSS score and gait performance alongside a marked reduction in KAM (all P < 0.001). STB-OWHTO exerted a greater coronal realignment effect on WBLR (group-by-time interaction P = 0.016), while it was associated with an increase in the posterior tibial slope (+ 5.26°, P < 0.001) and a reduction in patellar height (CDI = − 0.17, P < 0.001). Conversely, DTT-OWHTO preserved patellar height (insignificant CDI change, P = 0.169) and reduced the posterior tibial slope ( P = 0.003). Spatiotemporal gait improvements were similar between the two groups. Small between-group differences in stance-phase knee flexion were identified. Both STB-OWHTO and DTT-OWHTO provide early clinical improvement and effective medial compartment unloading during gait in varus knee osteoarthritis, while they produce distinct sagittal-plane and patellofemoral consequences. The osteotomy configuration should be individualized according to the patellofemoral status, ligament considerations, and the desired slope modification.