Usefulness of an insole with subtalar strapping for analgesia in patients with medial compartment osteoarthritis of the knee.

OBJECTIVE: To assess the effect of an insole with subtalar strapping on patients with medial compartment osteoarthritis (OA) of the knee.
METHODS: Novel lateral wedged insoles with elastic subtalar strapping (the subtalar strapping support group) and ankle supporters with a lateral wedged heel insert (the sock-type ankle support group) were prepared. Eighty-eight female outpatients with knee OA were treated with 1 of the 2 insoles for 8 weeks. Femorotibial angle was assessed by standing radiographs with and without unilateral insole use for each subject. Symptoms of knee OA were evaluated according to the severity index of Lequesne et al at baseline and at the final assessment.
RESULTS: Participants wearing the insole with subtalar strapping (n = 42) demonstrated significantly decreased femorotibial angle (an average of change: -3.1 degrees +/- 2.5 degrees, P < 0.0001), but a significant difference was not found in the sock-type ankle support group (n = 46; -0.4 degrees +/- 1.1 degrees, P > 0.05). In the subtalar strapping support group, pain during bed rest with full extension of the knee (P < 0.0001), pain after getting up (P = 0.04), pain on getting up from a seated position (P = 0.021), maximum distance walked (P = 0.009), and aggregate severity score (P < 0.0001) were significantly improved compared with baseline. In contrast, significant symptomatic improvement was detected only in the aggregate score (P = 0.016) in the sock-type ankle support group, but not in any of the 10 specific categories.
CONCLUSION: The lateral wedged insole with subtalar strapping induces correction of the femorotibial angle and symptomatic relief in patients with varus-deformity knee OA.