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Unloading Shoes for Self-management of Knee Osteoarthritis: A Randomized TrialUnloading Shoes for Self-management of Knee Osteoarthritis

Rana S. Hinman, BPhysio(Hons), PhD; Tim V. Wrigley, BSc(Hons), MSc; Ben R. Metcalf, BSc(Hons); Penny K. Campbell, BAppSci(FoodSci&Nutr); Kade L. Paterson, BAppSci(Hons), BPod, PhD; David J. Hunter, MBBS, PhD; Jessica Kasza, BSc(Hons), PhD; Andrew Forbes, BSc(Hons), MS, PhD; and Kim L. Bennell, BAppSci(Physio), PhD
[+] Article, Author, and Disclosure Information

This article was published at www.annals.org on 12 July 2016.


From University of Melbourne and Monash University, Melbourne, Australia, and University of Sydney, Sydney, Australia.

Acknowledgment: The authors thank Dr. Margaret Staples for performing the sample size calculation and preparing the randomization schedule.

Financial Support: The trial was funded by the National Health and Medical Research Council (project #1044396). Dr. Hinman is supported by an Australian Research Council Future Fellowship (FT130100175). Dr. Hunter is supported by a National Health and Medical Research Council Practitioner Fellowship (#1079777). Dr. Bennell is supported by a National Health and Medical Research Council Fellowship (#1058440).

Disclosures: Dr. Hinman reports grants from the National Health and Medical Research Council and the Australian Research Council Future Fellowship and royalties from ASICS Oceania during the conduct of the study. Mr. Wrigley reports grants from the National Health and Medical Research Council and royalties from ASICS Oceania during the conduct of the study. Mr. Metcalf reports grants from the National Health and Medical Research Council during the conduct of the study. Ms. Campbell reports grants from the National Health and Medical Research Council during the conduct of the study. Dr. Hunter reports personal fees from Flexion, Nestlé, Merck Serono, and DJO Global outside the submitted work. Dr. Bennell reports grants from the National Health and Medical Research Council and royalties from ASICS Oceania during the conduct of the study; grants from the Australian Research Council, the Medibank Health Research Fund, and the National Health and Medical Research Council outside the submitted work; and personal fees from ASICS Oceania and Physitrack outside the submitted work. Authors not named here have disclosed no conflicts of interest. Disclosures can also be viewed at www.acponline.org/authors/icmje/Conflict OfInterestForms.do?msNum=M16-0453.

Editors' Disclosures: Christine Laine, MD, MPH, Editor in Chief, reports that she has no financial relationships or interests to disclose. Darren B. Taichman, MD, PhD, Executive Deputy Editor, reports that he has no financial relationships or interests to disclose. Cynthia D. Mulrow, MD, MSc, Senior Deputy Editor, reports that she has no relationships or interests to disclose. Deborah Cotton, MD, MPH, Deputy Editor, reports that she has no financial relationships or interest to disclose. Jaya K. Rao, MD, MHS, Deputy Editor, reports that she has stock holdings/options in Eli Lilly and Pfizer. Sankey V. Williams, MD, Deputy Editor, reports that he has no financial relationships or interests to disclose. Catharine B. Stack, PhD, MS, Deputy Editor for Statistics, reports that she has stock holdings in Pfizer and Johnson & Johnson.

Reproducible Research Statement:Study protocol: Available via open access at www.bmcmusculoskeletdisord.bio medcentral.com/articles/10.1186/1471-2474-15-48. Statistical code: Available from Dr. Forbes (e-mail, Andrew.Forbes@monash.edu). Data set: Available from Dr. Hinman (e-mail, ranash@unimelb.edu.au).

Requests for Single Reprints: Rana S. Hinman, BPhysio(Hons), PhD, Centre for Health, Exercise and Sports Medicine, Department of Physiotherapy, The University of Melbourne, Level 7, Alan Gilbert Building, 161 Barry Street, Melbourne, 3010, Victoria, Australia; e-mail, ranash@unimelb.edu.au.

Current Author Addresses: Drs. Hinman, Paterson, and Bennell; Mr. Wrigley; Mr. Metcalf; and Ms. Campbell: Centre for Health Exercise and Sports Medicine, Department of Physiotherapy, The University of Melbourne, Level 7, Alan Gilbert Building, 161 Barry Street, Melbourne, 3010, Victoria, Australia.

Drs. Kasza and Forbes: Department of Epidemiology and Preventive Medicine, Monash University, The Alfred Centre, 99 Commercial Road, Melbourne, 3004, Victoria, Australia.

Dr. Hunter: Rheumatology Department, Royal North Shore Hospital, St. Leonards, 2065, New South Wales, Australia.

Author Contributions: Conception and design: R.S. Hinman, T.V. Wrigley, D.J. Hunter, A. Forbes, K.L. Bennell.

Analysis and interpretation of the data: R.S. Hinman, T.V. Wrigley, B.R. Metcalf, K.L. Paterson, D.J. Hunter, J. Kasza, A. Forbes, K.L. Bennell.

Drafting of the article: R.S. Hinman, B.R. Metcalf, P.K. Campbell, J. Kasza, A. Forbes.

Critical revision of the article for important intellectual content: R.S. Hinman, T.V. Wrigley, B.R. Metcalf, K.L. Paterson, D.J. Hunter, J. Kasza, A. Forbes, K.L. Bennell.

Final approval of the article: R.S. Hinman, T.V. Wrigley, B.R. Metcalf, P.K. Campbell, K.L. Paterson, D.J. Hunter, J. Kasza, A. Forbes, K.L. Bennell.

Provision of study materials or patients: B.R. Metcalf, P.K. Campbell, K.L. Bennell.

Statistical expertise: J. Kasza, A. Forbes.

Obtaining of funding: R.S. Hinman, T.V. Wrigley, D.J. Hunter, K.L. Bennell.

Administrative, technical, or logistic support: B.R. Metcalf, P.K. Campbell, K.L. Paterson.

Collection and assembly of data: B.R. Metcalf, P.K. Campbell, K.L. Paterson.


Ann Intern Med. 2016;165(6):381-389. doi:10.7326/M16-0453
© 2016 American College of Physicians
Text Size: A A A

Background: Appropriate footwear is recommended for self-management of knee osteoarthritis. Shoes that reduce harmful knee loads are available, but symptomatic effects are uncertain.

Objective: To evaluate the efficacy of unloading shoes in alleviating knee osteoarthritis symptoms.

Design: Participant- and assessor-blinded comparative effectiveness randomized, controlled trial. (Australian New Zealand Clinical Trials Registry: ACTRN12613000851763)

Setting: Community.

Participants: 164 persons with medial knee osteoarthritis.

Intervention: Walking shoes with triple-density, variable-stiffness midsoles and mild lateral-wedge insoles designed to unload the medial knee and worn daily (intervention) versus conventional walking shoes (comparator).

Measurements: Primary outcomes were pain with walking (assessed on a numerical rating scale [NRS]) and physical function (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]) at 6 months. Secondary outcomes were knee pain and stiffness (WOMAC), average pain (NRS), intermittent and constant knee pain (Intermittent and Constant Osteoarthritis Pain questionnaire), quality of life (Assessment of Quality of Life instrument), physical activity (Physical Activity Scale for the Elderly), and global change in pain and function (Likert scales).

Results: A total of 160 participants (98%) completed primary outcome measures at 6 months. Changes in pain (mean difference, 0.0 units [95% CI, −0.9 to 0.8 unit]) and function (mean difference, 0.3 unit [CI, −3.2 to 3.7 units]) did not differ between groups at 6 months, with both groups showing clinically relevant improvements in function and the intervention group showing clinically relevant improvements in pain. There were no differences in secondary outcomes. Pain was globally improved in 54% of participants, and function was globally improved in 44% to 48%. Unloading shoes were not associated with increased probability of improvement (odds ratios, 0.99 [CI, 0.53 to 1.86] for pain and 0.85 [CI, 0.45 to 1.61] for function).

Limitation: Effects on joint structure were not evaluated.

Conclusion: Shoes with modified midsoles to unload the medial knee conferred no additional benefit over conventional walking shoes. Both improved pain and function by clinically relevant amounts.

Primary Funding Source: Australian National Health and Medical Research Council.

Figures

Grahic Jump Location
Appendix Figure.

Intervention (unloading) shoes (top) and comparator (conventional) shoes (bottom).

Grahic Jump Location
Grahic Jump Location
Figure.

Study flow diagram.

The number of assessed participants is based on data obtained for the primary outcome measures. BMI = body mass index.

* 5 participants (3 in the intervention group and 2 in the comparator group) completed the 6-mo assessment after not completing the 3-mo assessment.

Grahic Jump Location

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Unloading shoes for self-management of knee osteoarthritis
Posted on July 31, 2016
Ryan T. Lewinson Ph.D., Darren J. Stefanyshyn Ph.D.
Human Performance Laboratory, University of Calgary, Calgary, Alberta, CA
Conflict of Interest: RTL and DJS disclose that they have submitted a Provisional US Patent for a method to predict biomechanical responses to footwear interventions.
The study by Hinman et al.(1) makes essential progress in the area of footwear for patients with knee osteoarthritis (OA). The study was quite rigorous, and it was especially interesting to note that no differences in clinical outcomes existed between the standardized shoe and unloading shoe groups over six months. We would like to put forth two possibilities for consideration that may help explain this finding.

First, Hinman et al.(1) utilized a standardized shoe as a control condition. While this or any other sham footwear may prevent differences between groups from placebo effects, these footwear are likely not true controls. Specifically, it has been documented that standardized shoes and other footwear control conditions such as flat insoles can significantly alter knee adduction moments (KAMs) during gait relative to a patient’s own footwear.(2) Thus by definition, standardized shoes may not be a true control condition since the primary variable believed to affect knee osteoarthritis progression (KAMs) may have been altered relative to baseline. We note the authors planned to measure gait biomechanics as an ancillary variable in the study, and so we wonder if data might be available to address this potential issue. It is possible that patients in the control group could have experienced a KAM reduction relative to what they encountered prior to the study, and thus experience clinical benefit.

Second, lateral wedge interventions do not always reduce KAMs – it has been estimated that nearly 25% of patients receiving a lateral wedge experience increased KAMs, which theoretically could lead to disease worsening.(3) Based on pilot results for the present trial,(4) the authors found that 13% of patients with knee OA may experience increased KAMs from the variable stiffness shoe utilized in their trial, potentially reducing the magnitude of clinical effect observed in the intervention group. In addition, it may be possible that while the unloading shoes reduce KAMs relative to the standardized shoe,(4) their effects might be quite different when evaluating KAM changes relative to the patient’s own shoes that they were wearing prior to the study. This could also reduce the overall observed clinical effect of the unloader shoes. Are results similar if analyses are restricted to only those who were confirmed to experience reduced KAMs?

We propose that the above two considerations, based primarily on the biomechanical changes experienced by both groups, may help explain why no difference was observed between groups in the trial.

References
1. Hinman RS, Wrigley TV, Metcalf BR, Campbell PK, Paterson KL, Hunter DJ, et al. Unloading Shoes for Self-Management of Knee Osteoarthritis: A Randomized Trial. Ann Intern Med. 2016 (Online ahead of print).
2. Lewinson RT, Worobets JT, Stefanyshyn DJ. Control conditions for footwear insole and orthotic research. Gait Posture. 2016;48:99-105.
3. Lewinson RT, Stefanyshyn DJ. Wedged Insoles and Gait in Patients with Knee Osteoarthritis: A Biomechanical Review. Ann Biomed Eng. 2016 (Online ahead of print).
4. Bennell KL, Kean CO, Wrigley TV, Hinman RS. Effects of a modified shoe on knee load in people with and those without knee osteoarthritis. Arthritis Rheum. 2013;65(3):701-9.
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