Internal kinetic changes in the knee due to high tibial osteotomy are well-correlated with change in external adduction moment: an osteoarthritic knee model.
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 (R(2)=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.
Bhatnagar
Timothy
T
Wolf Orthopaedic Biomechanics Laboratory, Fowler Kennedy Sport Medicine Clinic, The University of Western Ontario, Canada.
Jenkyn
Thomas R
TR
D001696:Biomechanical Phenomena; D005684:Gait / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008954:Models, Biological; D020370:Osteoarthritis, Knee / Q000503:physiopathology* / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D013997:Time Factors; D016138:Walking / Q000502:physiology