Pilot study of the effects of a heat-retaining knee sleeve on joint pain, stiffness, and function in patients with knee osteoarthritis.

Abstract

To identify changes in joint pain, stiffness, and functional ability in patients with knee osteoarthritis (OA) after use of a knee sleeve that prevents loss of body heat by the joint. Subjects with symptomatic knee OA (n = 52) were randomized to 2 treatment groups: verum sleeve (specially fabricated to retain body heat) or placebo sleeve (standard cotton/elastane sleeve). Subjects wore the sleeve over the more painful OA knee for at least 12 hours daily for 4 weeks. Pain, stiffness, and functional impairment (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]) in the index knee were measured at baseline and after 4 weeks of wear, after which sleeve use was discontinued. Telephone followup interviews were conducted 2 and 4 weeks later. After 4 weeks of sleeve wear, subjects in the active treatment group reported a 16% decrease in mean WOMAC pain score relative to baseline (P = 0.001). Those who wore the placebo sleeve reported a 9.7% decrease from baseline (P = 0.002). The difference between treatment groups was not statistically significant (P = 0.12). However, it was found that the 12 subjects who believed correctly that they had received the verum sleeve reported a highly significant decrease in WOMAC pain score (-27.5% relative to baseline, P = 0.0001). In comparison, subjects who received the verum sleeve but believed they had received the placebo sleeve exhibited only a marginally significant improvement in pain (-13.0% relative to baseline, P = 0.07). In the placebo group, the modest improvement in pain scores appeared unrelated to the subject's impression of the type of sleeve worn. This pilot study was insufficiently powered to be a definitive trial of the heat-retaining sleeve. Given the magnitude of changes in knee pain in the active treatment group, heat retention merits further scientific investigation as a treatment modality for patients with knee OA.