The lateral wedged insole with subtalar strapping significantly reduces dynamic knee load in the medial compartment gait analysis on patients with medial knee osteoarthritis.

OBJECTIVE Two lateral wedged insoles were compared: one with, and the other without, subtalar strapping. METHODS Twenty-one patients (age 58-83, mean 72) with medial knee osteoarthritis (OA) were enrolled. Thirty-seven knees in the patients were divided into three groups based on the Kellgren and Lawrence OA grading system; grades 2 (cases=20), 3 (cases=11), and 4 (cases=6). The subjects were tested during walking barefoot and during walking with a silicon rubber lateral wedged insole with elevation of 10 mm attached to a barefoot. Gait analysis was performed on a 10 m walkway for each subject under three different walking conditions; barefoot, wearing a conventional insole, and a subtalar strapping insole. Peak knee varus moment during gait was measured under each condition, and compared between the three conditions and between the OA grades. RESULTS On the whole (cases=37), the peak varus moment was significantly reduced by wearing either of the insoles, compared to walking barefoot. The reduction was more obvious with the strapping insole (-13%, P<0.01), compared with the conventional insole (-8%, P<0.05). In moderate OA patients (grades 2 and 3), the moments were significantly lower with the strapping insole, compared with the conventional insole (P=0.0048 and 0.005, respectively). However, no significant difference was detected in severe OA patients (grade 4) between the two types of insoles (P=0.4). CONCLUSIONS Both lateral wedged insoles significantly reduced the peak medial compartment load during gait. The subtalar strapping insole had a greater effect than the conventional insole, particularly in patients with moderate medial knee OA.