Electrogoniometry of post-surgical knee bracing in running.

The purpose of this study was to compare the dynamic range of motion at the knee of two knee braces worn during overground running. Six adult volunteers aged 22 to 28 were used as subjects. All subjects had a surgically repaired knee, a healthy contralateral knee, and were wearing the same type of derotation brace prescribed by their physician. Subjects ran through an experimental area at a slow running pace with the C.A.R.S.-U.B.C. electrogoniometer strapped to one limb. Three orthogonal potentiometers placed at the knee joint allowed the simultaneous collection of flexion-extension, inward and outward rotation, and varus-valgus motion parameters. Subjects completed five trials at each of four conditions; namely, healthy knee, surgically repaired knee, surgical knee fitted with an elastic support brace, and surgical knee fitted with a derotation brace. Results showed that the derotation brace had a general restraining effect on internal-external rotation of the surgically repaired knee. For all subjects, internal rotation was reduced by 22 percent and external rotation reduced by 31 percent. There was also an 11 percent reduction in the flexion-extension range of motion while subjects wore the derotation brace. The elastic support brace did not reduce any range of motion parameters. Additionally, the results revealed 5 percent greater flexion and extension in the non-surgical limb as compared to the surgical limb, with no differences exhibited in total rotation values. These results suggest that certain knee appliances do reduce range of motion parameters at the knee during the act of running.