All patients then underwent biomechanical assessment which consisted of motion analysis screening. Patients who did not show at least a 2% decrease in KAM after wearing the lateral wedge insoles versus the neutral insoles were excluded.
Of 112 subjects who were screened for the study, there remained 62 with a mean age of 64 years and body mass index of 28 kg/m2 who could be randomized. The subjects, 73% of whom were male, were randomized to first wear either neutral insoles or insoles with a lateral five-degree wedge for 8 weeks and then, after an 8-week washout period, to wear the other type of insole for a further 8 weeks. Participants wore the insoles for at least 4 hours a day and for a median of 7 hours per day.
Results showed that the lateral wedge insoles reduced KAM by 7.5% versus their own shoes and by 6.6% versus a neutral insole, and of the 62 patients randomized, 56 completed the trial. Two patients in each group stopped participating in the trial because of adverse events, which with lateral wedge insoles were cramps in the calf and foot and increased pain in the knee, and with the neutral insoles included a blister and increased pain in knee and foot.
At baseline, the mean global knee pain score in the last week was 5.46. After use of the lateral wedge or neutral insoles, this fell to a respective 4.2 and 4.9.