Rotational Profile after Biplane Medial Opening Wedge High Tibial Osteotomy: A Preliminary Report
Pitipong Joopibal MD1, Wirat Kongcharoensombat MD, PhD2
Affiliation : 1 Department of Orthopedics, Samutsakorn Hospital, Samutsakorn, Thailand 2 Institute of Orthopaedics, Lerdsin General Hospital, Bangkok, Thailand
Background : High tibial osteotomy [HTO] is a surgical procedure for treatment of medial compartmental osteoarthritis
combined with varus deformities of the knee in middle-aged patients. The goal of this procedure is to shift the weight-bearing
axis from the medial compartment to the lateral compartment of the knee joint, resulting in a change of knee alignment from
varus to valgus. Although changing the coronal plane is the main purpose of high tibial osteotomy, changes in axial rotation
after the procedure has been documented in previous studies. Unintentional change in the axial plane following HTO has been
proposed as one of the factors that influence overall gait mechanics and patellofemoral kinematics.
Objective : This study aimed to measure changes in the degree of rotation in the axial plane resulting from biplane medial
opening wedge high tibial osteotomy [MOWHTO].
Materials and Methods: Nine patients with medial compartmental osteoarthritis combined with varus deformity were
enrolled in this study. Biplane MOWHTO with medial high tibia plate fixation was performed on all the patients by a single
surgeon. The change in rotational profile of the tibia after surgery was determined by comparing the pre- and post-surgery
angle between the proximal posterior tibial axis and the distal bimalleolar axis using CT scans. The data were analyzed using
a paired t-test. Values of p<0.05 were considered statistically significant.
Results : A change in rotational profile after biplane MOWHTO was found in all patients. Eight patients showed external
rotation and one patient showed internal rotation. However, the change in the degree of axial rotation was not significant.
Conclusion : Although not significant, minor changes in the degree of rotation were detected. Those changes suggest that an
unintended rotation of the tibia could have occurred during biplane MOWHTO, especially changes in the external rotation
patterns. Unintended rotation of the tibia is a factor that needs be considered during the opening of the osteotomy gap in high
tibial osteotomy.
Keywords : HTO; Biplane; Medial opening wedge high tibial osteotomy; Rotation profile; External rotation
