Analysis of biomechanical effectiveness of valgus-inducing knee brace for osteoarthritis of knee.

The biomechanical effectiveness of a valgus-inducing knee brace was investigated for 16 patients with knee osteoarthritis (mean +/- standard deviation age 56 +/- 10 yr, height 172 +/- 9 cm, mass 83 +/- 7 kg, body mass index 27.6 +/- 4.5 kg/m(2)). At the time of investigation, all subjects had been wearing the brace for at least 4 weeks. In addition to conducting standard gait analysis, we calculated the valgus moment generated by the brace by using a novel system that measured the actual deformation of the brace during stance phase and determined the reaction force created by the brace on the leg. The mean maximum value of the orthotic valgus moment was 0.053 Nm/kg, which represents approximately 10% of the external genu varus moment without the brace. This finding may explain the pain relief reported by patients using such braces in clinical studies. Use of the tested brace also decreased the magnitude of gait asymmetry between the braced and contralateral legs during walking (horizontal ground reaction force, external knee flexion moment), presumably because the subjects' need to walk abnormally to shield the knee from pain was reduced.