Abstract
Introduction and Aims: High tibial osteotomy (HTO) is a corrective surgical procedure used to treat medial compartment osteoarthritis (OA). In HTO a bone wedge is resected from the upper tibia to realign the lower limb. In this study, we investigated the effect of HTO on patellofemoral joint motion using a validated new technique.
Method: We assessed patellar tracking in four subjects before and after high tibial osteotomy surgery. A high-resolution MR image was acquired of each subject’s knee. Each subject then loaded his/her knee in a custom test rig in the MR scanner, while fast, low-resolution MRI scans were acquired. This was repeated at five flexion angles. Bone outlines were identified (image segmentation) and processed (meshed) to yield bone models. Knee kinematics were determined by matching (registering) the high-resolution bone models to the low-resolution bony outlines. We compared the pre- and post-operative tracking patterns using a two-way repeated measures ANOVA.
Results: The resultant patellar tracking patterns were expressed as a function of knee flexion. Mean values for each quantity were calculated over the flexion range. High tibial osteotomy decreased patellar flexion by a mean of 5.06 degrees (p < 0.003), decreased internal patellar spin by a mean of 1.25 degrees (p < 0.001) and increased medial patellar tilt by a mean of 1.59 degrees (p < 0.001). High tibial osteotomy increased proximal patellar translation by a mean of 4.19mm (p < 0.008), but, for the number of specimens tested, we found no significant change in anterior or medial translation.
Conclusion: Our finding that HTO translated the patella proximally is consistent with findings of elevated patellae in the literature. The significant changes in patellar movement caused by high tibial osteotomy surgery suggest that the post-operative anterior knee pain associated with these procedures is due to mechanical changes at the patellofemoral joint.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
One or more of the listed authors are receiving or have received benefits or support from a recognised academic body for the pursuance of the study.
