Author and graduation date: Matthew DONOHOE, November, 1999

Committee members: Peter R. Francis (Chair), Roger Simmons, Robert S. Pozos

Thesis title: The Effects of Valgus Loading Osteoarthritis Knee Braces on the Electromyographical Activity of Selected Muscles and Immediate Pain of Female Participants

The purpose of this investigation was twofold. First, to determine if valgus loading OA knee braces, the Monarch and Opal, decrease the muscle activity of the rectus femoris, vastus medialis, vastus lateralis, and the rectus femoris. Second, to determine if a valgus loading knee brace designed for females (the Opal) would produce a reduction in knee pain after immediate application in females.

Participants in the investigation were 6 females with a mean age of 65.8 years, + 15.8 years, with an average duration of OA being 7.7 years, + 6.3 years. The participants recorded their average pain level on a visual analog scale and then walked 15.24 meters at a pace of one step a second with and without the two braces. EMG activity of four of the muscles surrounding the knee were recorded during walking. It was hypothesized that these muscles would be less active due to the compensatory effects of the braces. Immediately after the wearing the Opal knee brace the participants again recorded pain level on a visual analog scale. Results of a 3 x 4 (brace x muscle) mixed model repeated measures analysis of variance indicated a nonsignificant muscle effect (F(3,45) = 2.453; p = 0.076), a nonsignificant brace effect (F(2,15) = 1.498; p = 0.255), and a nonsignificant interaction (F(6,45) = 0.266; p = 0.950). A one-way repeated measures analysis of variance indicated a significant difference between pre and post pain scores (F(1,5) = 13.663; p = 0.004) with the Opal valgus loading knee brace yielding significantly lower pain scores than the unbraced condition.

It was concluded that neither the Monarch nor the Opal produces a significant decrease in the muscular activity of the rectus femoris, vastus medialis, vastus lateralis, or the biceps femoris during level walking. It was also concluded that the Opal valgus loading OA knee brace significantly reduces knee pain and the pain relief can be expected to occur soon after brace application.

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