Instrumental gait analysis and tibial-plateau modelling to support pre- and post-operative evaluations in personalized high tibial osteotomy

High Tibial Osteotomy (HTO) is intended to treat medial knee osteoarthritis by realigning the joint such that the loading in the knee during functional activity shifts laterally. The aim of this study was to use a novel methodology combining motion analysis and 3D modelling to assess the efficacy of this surgery in changing the loading location in the knee in a cohort of 25 patients treated with personalised HTO. Pre-operatively and at 6 months post-surgery, weight-bearing CT and gait analysis during level-walking were performed on all patients, as well as clinical evaluations using KOOS and VAS scores. CT scans were used to generate a knee bone model and a virtual tibial-plateau plane; the intersection pattern between this plane and the ground reaction force (GRF) vector was calculated in the pre- and post-operative gait analyses. Clinical scores improved significantly (p<0.001) after surgery (pre-/post-operative KOOS and VAS: 56.2±14.0 / 82.0±8.3 and 6.3±1.7 / 1.5±1.7). Post-operative GRF-to-tibial-plateau intersection patterns were significantly (p<0.001) more lateral (31.9±19.8% of tibial plateau width) than the pre-operative patterns. Personalised HTO successfully and consistently lateralises the GRF at the knee, in association with significant improvements in function and pain. The novel combination of 3D bone modelling and motion analysis has also the potential to further aid HTO surgical planning.