October 2011

Dynamic duo

In the moment: Knee OA

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Brace-wedge combo maximizes results

Wedged foot orthoses and knee braces have both been shown to relieve knee osteoarthritis symptoms, but research from the University of Western Ontario suggests that the two modalities may be most effective when used in combination.

By Jordana Bieze Foster

“Wearing both devices may be more beneficial than either one on its own,” said Rebecca Moyer, PT, a doctoral student in the Health and Rehabilitation Sciences graduate program at UWO, who presented her group’s findings in September at the Osteoarthritis Research Society International (OARSI) World Congress on Osteoarthritis.

The investigators performed 3D gait analysis on 15 patients with medial compartment knee OA under four conditions: with laterally wedged foot orthoses, with a custom unloading knee brace, with both devices, and with neither. The foot orthoses were customized to provide the maximum amount of wedging tolerated by each patient, starting at 3°; wedging adjustments were made while the patients were braced. Each patient had at least six months of experience with brace wear, but the study protocol did not include an acclimatization period for the wedge orthoses.

No significant differences between conditions were seen on standing radiographs. In addition, the control condition was not significantly different from bracing alone or orthoses alone with regard to knee adduction moment or frontal plane lever arm. However, when the braces and orthoses were worn together, both knee adduction moment and frontal plane lever arm improved significantly compared to the control condition.

The combination therapy may have a positive additive effect, but it also may present twice as many compliance issues, Moyer noted. Previous studies and anecdotal reports have documented the challenges in convincing patients to wear just one OA device—a theme that was repeated in a second OARSI presentation from Hiroshima University in Japan.

The Japanese researchers analyzed 118 patients with medial compartment knee OA who were assigned to one of three groups: a laterally wedged insole group, a valgus unloading brace group, and a control group in which patients were instructed to exercise but did not wear any orthotic devices. Patients were not evenly distributed among groups, however, with  44 patients in the control group and 55 in the insole group compared to just 19 in the bracing group. Those in the bracing group also had more severe OA than those in the other two groups, with higher Kellgren-Lawrence radiographic scores, higher pain levels, and more limited knee extension range of motion (ROM) at baseline.

“Originally, we wanted to perform a randomized study, but many of our patients objected to being in the bracing group,” said Masataka Deie, MD, a researcher in the department of orthopedic surgery at the university, who presented his group’s findings at the OARSI congress.

Despite the unequal distribution of study participants, the researchers found that the wedged orthoses and, in particular, the unloading brace were associated with improvements in pain and function at six months and one year compared to baseline.

Gait speeds in both brace and insole groups significantly improved at six months and one year compared to baseline levels. Pain during walking, as measured on a visual analog scale, improved in the bracing group to the point at which it was not significantly different from the control group at 12 months. Knee extension ROM also had significantly improved in the brace group at the one-year mark, although it remained lower than in the other two groups.

Both the insoles and the brace were associated with decreases in medial knee varus moment, but the patterns of improvement differed: In the brace group the decreases occurred gradually whereas the insole group had an initial decrease followed by a plateau.

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