Upcoming Event

Johnson & Johnson Mechanical Testing and Analysis Summit 
Robb Colbrunn, Ph.D., Guest Speaker
Director of BioRobotics and Mechanical Testing Core
Medical Device Solutions (MDS) Cleveland Clinic
Adjunct Assistant Professor, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University
September 18-20, 2018
Syracuse, IN

The Effect of Medial Opening Wedge High Tibial Osteotomy on Medial Collateral Ligament Tension

Client: Steve Fening Ph.D. and Lutul Farrow M.D. / Cleveland Clinic

Services Provided: Experiment Design / Robotic Knee Joint Testing / Manuscript Preparation

Medial opening wedge high tibial osteotomy (HTO) as utilized for varus gonarthrosis shifts the lower extremity weight-bearing axis towards the intact lateral compartment. Agneskirchner et al recently demonstrated that medial compartment pressures actually increased following medial opening wedge HTO. They hypothesized that this was due to increased medial collateral ligament (MCL) tension, but this was not actually measured. Our first hypothesis is that MCL strain increases following HTO. Our second hypothesis is that MCL strain will decrease following partial MCL release. The objective of this study is to determine how medial opening wedge HTO effects MCL tension. Differential variable reluctance transducer strain gauges were placed at the mid-substance of the superficial and posterior oblique portions of the MCL. Each knee was tested using a 6-degree of freedom robotic simulator. We tested 4 conditions: intact knee, 1 cm opening wedge HTO, partial MCL release, and complete MCL release. The clinical exam variable consisted of a simulated Lachman’s exam and varus-valgus stress testing. Simulated gait consisted of a 1000 N of compressive force combined with variable varus torques from 0 to 40 N-M. Each test was performed at 0 and 30 degrees of flexion. The principal findings of our study demonstrate that superficial MCL tension does not change significantly but tension in the posterior oblique portions of the MCL do change significantly following medial opening wedge HTO. Our findings suggest that the increased medial compartment contact pressures seen following HTO may be the result of increased posterior oblique tension alone. Furthermore, partial release of the superficial MCL and posterior oblique portion did not significantly affect ligament tension.