Osseous factors influencing distal tibial rotation in biplane medial opening wedge high tibial osteotomy.

Abstract

There is a lack of studies investigating the distal tibial rotation (DTR) during medial opening wedge high tibial osteotomy (MOWHTO). This study was designed to evaluate osseous factors influencing DTR in patients who underwent biplane MOWHTO. A total of 106 knee joints in 69 patients who underwent surgery for varus malalignment of knee were reviewed. Based on several software, standard and actual hinge positions were defined in pre-operative and post-operative CT data. Pearson's correlation and Spearman's correlation analysis were performed with DTR change as the dependent variable. Independent variables included angles between standard and actual hinge in the sagittal (ASAHS) and axial (ASAHA) planes, pre-operative and post-operative medial proximal tibial angle, opening width (OW), tuberosity osteotomy angle, flange angle (FA), gap ratio, and hinge fracture. The distal tibia rotated approximately 0.35° internally. Pearson's and Spearman's correlation analysis showed that DTR change was associated with ASAHS, OW, and FA. Larger OW and FA resulted in higher external rotation angles. DTR change was significantly associated with ASAHS, followed by OW and FA rather than ASAHA if only considering osseous factors in biplane MOWHTO. The distal tibia tended to rotate externally when the actual hinge was inclined posteriorly to the standard hinge in the sagittal planes, but rotate externally or internally when the actual hinge was inclined anteriorly.