Effect of variable-stiffness walking shoes on knee adduction moment, pain, and function in subjects with medial compartment knee osteoarthritis after 1 year

J Orthop Res. 2012 Apr;30(4):514-21. doi: 10.1002/jor.21563. Epub 2011 Sep 23.


This study investigated the load-modifying and clinical efficacy of variable-stiffness shoes after 12 months in subjects with medial compartment knee osteoarthritis. Subjects who completed a prior 6-month study were asked to wear their assigned constant-stiffness control or variable-stiffness intervention shoes during the remainder of the study. Changes in peak knee adduction moment, total Western Ontario and McMaster Universities (WOMAC), and WOMAC pain scores were assessed. Seventy-nine subjects were enrolled, and 55 completed the trial. Using an intention-to-treat analysis, the variable-stiffness shoes reduced the within-day peak knee adduction moment (-5.5%, p < 0.001) in the intervention subjects, while the constant-stiffness shoes increased the peak knee adduction moment in the control subjects (+3.1%, p = 0.015) at the 12-month visit. WOMAC pain and total scores for the intervention group were significantly reduced from baseline to 12 months (-32%, p = 0.002 and -35%, p = 0.007, respectively). The control group had a reduction of 27% in WOMAC pain score (p = 0.04) and no significant reduction in total WOMAC score. Reductions in WOMAC pain and total scores were similar between groups (p = 0.8 and p = 0.47, respectively). In the intervention group, reductions in adduction moment were related to improvements in pain and function (R(2) = 0.11, p = 0.04). Analysis by disease severity revealed greater efficacy in adduction moment reduction in the less severe intervention group. While the long-term effects of the intervention shoes on pain and function did not differ from control, the data suggest wearing the intervention shoe reduces the within-day adduction moment after long-term wear, and thus should reduce loading on the affected medial compartment of the knee.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aged
  • Arthralgia / physiopathology
  • Arthralgia / rehabilitation
  • Female
  • Follow-Up Studies
  • Gait / physiology*
  • Humans
  • Knee Joint / physiology
  • Male
  • Middle Aged
  • Movement / physiology*
  • Orthotic Devices / standards*
  • Osteoarthritis, Knee / physiopathology*
  • Osteoarthritis, Knee / rehabilitation*
  • Severity of Illness Index
  • Shoes / standards*
  • Walking / physiology
  • Weight-Bearing / physiology