Internal kinetic changes in the knee due to high tibial osteotomy are well-correlated with change in external adduction moment: An osteoarthritic knee model

Bhatnagar, Timothy; Jenkyn, Thomas R.

doi:10.1016/j.jbiomech.2010.05.001

« Previous Next »Journal of Biomechanics
Volume 43, Issue 12 , Pages 2261-2266, 26 August 2010

Internal kinetic changes in the knee due to high tibial osteotomy are well-correlated with change in external adduction moment: An osteoarthritic knee model

Timothy Bhatnagar
- Wolf Orthopaedic Biomechanics Laboratory, Fowler Kennedy Sport Medicine Clinic, The University of Western Ontario, Canada
- Graduate Program in Biomedical Engineering, Faculty of Engineering, The University of Western Ontario, Canada
Thomas R. Jenkyn
- Wolf Orthopaedic Biomechanics Laboratory, Fowler Kennedy Sport Medicine Clinic, The University of Western Ontario, Canada
- Graduate Program in Biomedical Engineering, Faculty of Engineering, The University of Western Ontario, Canada
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, Canada
- Department of Mechanical and Materials Engineering, Faculty of Engineering, The University of Western Ontario, London, Ontario, Canada N6A 5B9
- Corresponding author at: Department of Mechanical and Materials Engineering, Faculty of Engineering, The University of Western Ontario, London, Ontario, Canada N6A 5B9. Tel.: 15196612111x88339; fax: 15196613020.

Accepted 7 May 2010. published online 30 June 2010.

Abstract

In-vivo quantification of loads in the constitutive structures of the osteoarthritic knee can provide clinical insight, particularly when planning a surgery like the opening-wedge high tibial osteotomy (HTO). A computational knee model was created to estimate internal kinetics during walking gait. An optimization approach partitioned loads between the muscles, ligaments, medial and lateral contact surfaces of the tibial–femoral joint. Three kinetic measures were examined in 30 HTO patients: external knee adduction moment (EKAM), medial compartment load (ML) and the medial-to-lateral compartment loads ratio (MLR). Three time points were compared: immediately pre-HTO, 6 and 12 months post-HTO. Three hypotheses were tested: (1) HTO reduces an EKAM, an ML and an MLR, (2) these measures are not significantly different at 6 and 12 months post-HTO, and (3) the change in the impulse of EKAM due to a HTO is well-correlated with the impulse of an MLR.

The three hypotheses were confirmed. First peak of an EKAM during stance phase was reduced significantly by 1.70% BW-ht. ML and MLR at the same instance were reduced significantly by 0.56%BW and 1.0, respectively. These measures were not significantly different between 6 and 12 months post-HTO. Changes in impulse of an EKAM and an MLR were moderately well-correlated between the pre-HTO and 6 months post-HTO time points (R²=0.5485). Therefore, the external measure EKAM-impulse is a good proxy of the internal kinetic measure of an MLR-impulse, explaining about 55% of the variance in the change due to a HTO intervention.

Keywords: Knee osteoarthritis, Adduction moment, Optimization model, Gait analysis, Internal loading, Walking gait