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Background: This study aimed to evaluate post-operative lower limb function following second-generation mechanically aligned medial pivot (MP) TKA implantation. Standard gait analysis was performed to collect kinematic and kinetic data, which were then compared with physiological data from the literature obtained using the same evaluation methodology as the present study. The hypothesis was that this TKA would not fully restore normal knee and adjacent joint motion during walking. Methods: Our cohort comprised 15 patients consecutively enrolled from September 2019 to December 2022 who underwent primary TKA with the second-generation MP Evolution Knee System (MicroPort Orthopaedics Inc., Arlington, TN, USA). Pre-operatively and 6 months post-surgery, gait analysis during level walking was performed on all patients, as well as clinical evaluations using the Knee Society Score (KSS), the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the Visual Analogue Scale (VAS). Results: The clinical scores improved significantly (p < 0.001) after surgery (pre-/post-operative KSS functional, KSS clinical, VAS, and KOOS: 51.7 ± 17.3/84 ± 18.4, 45.3 ± 16.2/74.1 ± 12.6, 6.9 ± 1.8/2.0 ± 1.9, and 33.9 ± 11.8/69.1 ± 16.5, respectively). The statistical parametric mapping (SPM) analysis between the post-operative and reference control data revealed significant differences in the initial and final 20% of the gait cycle for the rotation of the knee in the frontal and transverse planes and for the rotation of the ankle in the sagittal plane. Conclusions: This study shows that new-generation MP TKA with mechanical alignment does not fully restore normal gait biomechanics, particularly in knee rotational movements, indicating a need for improved surgical techniques and prosthetic designs. [ABSTRACT FROM AUTHOR]

Featured Application: The inclusion of gait analysis, suitably combined with anatomical modelling derived from patient-specific medical imaging, may lead in the near future to more robust post-operative evaluations of personalized HTO to support the efficacy of this surgical technique, as well as innovative and more biomechanically based pre-operative planning. 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 personalized 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. Personalized HTO successfully and consistently lateralizes the GRF at the knee, in association with significant improvements in function and pain. The novel combination of 3D bone modelling and motion analysis also has the potential to further aid HTO surgical planning. [ABSTRACT FROM AUTHOR]