Effects of laterally wedged insoles on symptoms and disease progression in medial knee osteoarthritis: a protocol for a randomised, double-blind, placebo controlled trial

Kim Bennell¹ , Kelly-Ann Bowles¹ , Craig Payne² , Flavia Cicuttini³ , Richard Osborne⁴ , Anthony Harris⁵ and Rana Hinman¹

¹Centre for Health, Exercise & Sports Medicine, School of Physiotherapy, University of Melbourne, Australia

²Department of Podiatry, School of Human Biosciences, LaTrobe University, Melbourne, Australia

³Department of Epidemiology and Preventive Medicine, Alfred Hospital, Monash University, Melbourne, Australia

⁴AFV Centre for Rheumatic Diseases, Department of Medicine (RMH/WH), University of Melbourne, Australia

⁵Health Economics Unit, Monash University, Melbourne, Australia

author email corresponding author email

BMC Musculoskeletal Disorders 2007, 8:96doi:10.1186/1471-2474-8-96


Published:	24 September 2007

Abstract

Background

Whilst laterally wedged insoles, worn inside the shoes, are advocated as a simple, inexpensive, non-toxic self-administered intervention for knee osteoarthritis (OA), there is currently limited evidence to support their use. The aim of this randomised, double-blind controlled trial is to determine whether laterally wedges insoles lead to greater improvements in knee pain, physical function and health-related quality of life, and slower structural disease progression as well as being more cost-effective, than control flat insoles in people with medial knee OA.

Methods/Design

Two hundred participants with painful radiographic medial knee OA and varus malalignment will be recruited from the community and randomly allocated to lateral wedge or control insole groups using concealed allocation. Participants will be blinded as to which insole is considered therapeutic. Blinded follow up assessment will be conducted at 12 months after randomisation. The outcome measures are valid and reliable measures recommended for OA clinical trials. Questionnaires will assess changes in pain, physical function and health-related quality-of-life. Magnetic resonance imaging will measure changes in tibial cartilage volume. To evaluate cost-effectiveness, participants will record the use of all health-related treatments in a log-book returned to the assessor on a monthly basis. To test the effect of the intervention using an intention-to-treat analysis, linear regression modelling will be applied adjusting for baseline outcome values and other demographic characteristics.

Discussion

Results from this trial will contribute to the evidence regarding the effectiveness of laterally wedged insoles for the management of medial knee OA.

Trial registration

ACTR12605000503628; NCT00415259.