Proximal fibula osteotomy (PFO) is a relatively new surgery to treat medial compartment knee osteoarthritis (KOA), which can improve varum deformity and relieve knee joint pain. However, the gait alterations in KOA patients after PFO are still poorly understood. The purpose of this study was to evaluate the gait patterns change in patients of medial compartment KOA after PFO. Gait data were collected for 9 females with unilateral medial compartment KOA before and at 6 months after PFO and also for 9 healthy age-matched females. Paired t -test was used to determine the effect of PFO within the KOA group, and independent t -test were performed to compare between KOA and control groups for spatiotemporal, kinematic, and kinetic variables. The results showed that patients with KOA had significantly increased knee peak flexion angle, knee sagittal range of motion, and peak external hip adduction moment but decreased knee frontal range of motion in the affected limb after PFO. The gait symmetry was improved postoperatively confirmed by single support and swing phases, knee peak flexion angle and sagittal range of motion, peak external hip and knee adduction moments, and peak anterior and peak posterior ground reaction forces. These findings provided evidence of a biomechanical benefit and gait improvement following PFO to treat medial compartment KOA.

The purpose of this study was to investigate the effect of tibial insertion site (TIS) of the anterior cruciate ligament (ACL) in single-bundle ACL reconstruction on ligament force during gait. A musculoskeletal model with an ACL ligament was created, and gait data were collected based on the motion capture system from seven female patients with single-bundle ACL reconstruction. The TIS was simulated in OpenSim and systematically changed in 2.5 mm intervals (2.5 mm, 5.0 mm, and 7.5 mm) in the anteroposterior and mediolateral directions from the center. The changes of the ACL force overtime and peak force were compared using the Pearson correlation and paired t-test separately for all simulated TISs. The results indicated that anterior movement of the TIS would significantly increase the loading of reconstructed ACL and the risk of secondary injury, but the posterior TIS would keep the ACL loose during gait. The mediolateral change of the TIS also affected the ligament force during gait, which increased in the medial direction and decreased in lateral direction, but the magnitude of the change is relatively small compared with those measured in the anteroposterior direction. Therefore, during preoperative surgery planning, defining the outline of the ACL attachment site during surgery can help to guide the decision for the TIS and can significantly affect the reconstructed ACL force during gait, especially if the TIS is moved in the anteroposterior direction.