Efficacy of methylsulfonylmethane supplementation on osteoarthritis of the knee: a randomized controlled study

Debbi EM, Agar G, Fichman G, et al. · BMC Complementary and Alternative Medicine

Between groups over 12 weeks, WOMAC physical function differed by 14.6 mm (95% CI 4.3 to 25.0; p=0.04) and WOMAC total by 15.0 mm (5.1 to 24.9; p=0.03). WOMAC pain (12.4 mm, 0.0 to 24.8) and stiffness (27.2 mm, 8.2 to 46.2) did not separate, both p=0.08, and neither did the aggregated locomotor function score (p=0.09), SF-36 (p=0.54) or either Knee Society score. Most of the separation is the placebo arm getting worse rather than MSM getting better: on MSM function improved 17% and total symptoms 20%, while on placebo function worsened 15%, total 14%, pain 9% and stiffness 37%. The authors' own reading is that the improvements are small and of undetermined clinical significance.

Population

Adults with radiographic knee osteoarthritis, Israel

Intervention

MSM 1.125 g three times daily (3.375 g/day) for 12 weeks

Comparator

Placebo

Limitations

Small and short. Allocation was not concealed: patients took a sequential enrolment number and every even number received MSM, every odd number placebo, so the assignment was predictable from the order of arrival. The groups differed significantly at baseline in gender, body mass index and locomotor function, and the analyses are adjusted for that rather than balanced by design. Several reported confidence intervals sit at odds with their p values — stiffness spans 8.2 to 46.2 at p=0.08, the VAS difference spans -0.9 to 2.4 at p=0.05.