In vivo Knee Kinematics during Step-up Activity after Medial Opening Wedge Distal Tuberosity Osteotomy of the Proximal Tibia with Hemicallotasis

Abstract

Abstract Purpose Hemicallotasis osteotomy (HCO), a type of medial opening wedge distal tuberosity osteotomy of the proximal tibia (OWDTO), aims to correct the alignment of knees with osteoarthritis (OA). HCO shifts the weight burden to the lateral compartment, facilitating the transfer of load from the medial compartment of the joint line to the lateral compartment. This technique results in reduced compartmental pressure on the medial articular surface, and fewer knee adduction movements. However, HCO’s impact on knee joint kinematics is currently unclear. Therefore, we conducted a 3-dimensional analysis of the in vivo dynamics during stair-climbing motions, before and after HCO. Methods Six out of 13 patients who underwent HCO to treat unilateral medial knee OA were included in this study. The mean age of subjects at the time of HCO was 61 ± 6 years. Subjects performed the ascending motion using a step platform preoperatively, and 1 year postoperatively, and fluoroscopic lateral images were taken on both occasions. Three-dimensional kinematic analysis was conducted using the model-based image-matching technique. Results The tibias exhibited a pattern of external rotation according to the degree of extension, both preoperatively (10°±3°) and postoperatively (8°±4°), but these differences were not significant. Additionally, no significant differences were observed in the anteroposterior movement of the femoral condyles, before and after HCO. The lateral femoral condyle was shifted by 10 ± 1 mm from the flexion position to the extension position prior to HCO, and 9 ± 1 mm postoperatively. Conclusion Although no significant differences were observed during this study, it is possible for the medial pivot movement to decrease during HCO due to the shift in the center of gravity to the lateral side of the joint line.