Gait analysis study on patients with varus osteoarthrosis of the knee.

Biomechanical changes that occur after high tibial osteotomy (HTO) was investigated in 30 patients with osteoarthrosis (OA) of the knee and 11 age-matched normal subjects. Of the 37 knees with varus OA evaluated, 21 were analyzed before and after surgery (average follow-up evaluation, two years). The mean age of the patient group was 58.2 years. Clinical assessment was based on the Hospital for Special Surgery (HSS) knee scoring system. Full-length weight-bearing radiograms were taken for the measurement of the mechanical axis of the lower limb. Results from clinical assessment showed that 90% of the patients had good or excellent postoperative clinical results, as opposed to 9.5% before surgery. An overall improvement in the gait parameters was evident in the group evaluated after surgery, although control levels were not attained. Further analysis based on moments about the knee showed that 57% of the surgically treated knees with good or excellent clinical results had abnormal load distribution. This may lead to deterioration in the future, and further surgery may be required. The abnormal loading was also reflected in the ground-reaction force vector diagram. Therefore, the force vector diagram can be used as a quick screening method to detect abnormal joint loading.