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Losing control over control conditions in knee osteoarthritis orthotic research
Contemporary Clinical Trials 42 (2015) 258–259
Contents lists available at ScienceDirect
Contemporary Clinical Trials journal homepage: www.elsevier.com/locate/conclintrial
Letter to the Editor Losing control over control conditions in knee osteoarthritis orthotic research
Keywords: Control Biomechanics Footwear Knee osteoarthritis Gait
Wedged footwear orthotics/insoles have been studied extensively as a strategy to reduce the peak knee adduction moment (a measure of knee joint load) for individuals with knee osteoarthritis [1–3]. While consistent biomechanical efficacy has been found for wedged insoles [1], their clinical efficacy differs dramatically across studies [2]. Recently, Parkes et al. [2] published a meta-analysis where they proposed that different footwear control conditions used across studies could explain the differing clinical results. These authors advocated, on the basis of controlling placebo effects, that a flat insole within the participant's own shoe should be the control condition of choice for future trials. Certainly, placebo effects are an important consideration when designing a clinical trial; however, in the case of an intervention designed to alter knee joint loading, the primary objective for a control group should be ensuring that the groups' biomechanics remain unchanged relative to what they normally experience. This is analogous to drug trials, where researchers must ensure that the control condition is chemically inert. So in the case of a flat insole for knee osteoarthritis trials, do we know for certain that they are biomechanically inert at the knee, in the same way that we know a sugar-pill will not contain any active medication? Currently, no direct evidence is available to decisively answer this question; however, recent work by McCormick et al. [4] suggests that we should proceed with caution. Specifically, these researchers found that flat insoles can induce altered pressure distributions beneath the foot, which has been shown on numerous occasions to be correlated with a change in magnitude of the peak knee adduction moment [5,6]. Therefore, it is possible that previous studies utilizing a flat insole as a control condition may have actually induced altered knee biomechanics in the control group, consequently biasing study clinical outcomes.
http://dx.doi.org/10.1016/j.cct.2015.03.011 1551-7144/© 2015 Elsevier Inc. All rights reserved.
In light of the work by McCormick and colleagues [4], and contrary to the recommendations by Parkes et al. [2], we propose that currently, it is best to err on the side of caution and utilize the participants' own footwear as a control condition, thus ensuring the participants' biomechanics are unchanged relative to what they normally experience. This method does not directly account for placebo effects, so researchers will need to consider this when interpreting their results. For instance, if a positive effect of insoles is found over a control group where the participant's own footwear is used, we advise that researchers attempt to explain why this effect occurred. One approach may be to assess if a correlation exists in the insole group between the change in knee adduction moment induced by the insoles, and change in pain over the duration of the study — a significant correlation would indicate clinical benefits were related to a biomechanical change, and not exclusively attributed to placebo effects. It seems clear that there is an urgent need to invest time into studying what can serve as a proper footwear control condition for knee osteoarthritis trials. This will help to address biomechanical and placebo issues, and stimulate consistency in control conditions across trials. Acknowledgments RTL is funded by the Vanier Canada Graduate Scholarship program through the Canadian Institutes of Health Research, the Natural Sciences and Engineering Research Council of Canada CREATE Program, the Alberta Innovates-Health Solutions MD/PhD Program, and the Killam Trusts. References [1] Reeves ND, Bowling FL. Conservative biomechanical strategies for knee osteoarthritis. Nat Rev Rheumatol 2011;7:113–22. [2] Parkes MJ, Maricar N, Lunt M, LaValley MP, Jones RK, Segal NA, et al. Lateral wedge insoles as a conservative treatment for pain in patients with medial knee osteoarthritis: a meta-analysis. JAMA 2013;310:722–30. [3] Hinman RS, Bennell KL. Advances in insoles and shoes for knee osteoarthritis. Curr Opin Rheumatol 2009;21:164–70. [4] McCormick CJ, Bonnano DR, Landorf KB. The effect of customized and sham foot orthoses on plantar pressures. J Foot Ankle Res 2013;6:19. [5] Hinman RS, Bowles KA, Metcalf BB, Wrigley TV, Bennell KL. Lateral wedge insoles for medial knee osteoarthritis: effects on lower limb frontal plane biomechanics. Clin Biomech 2012;27:27–33. [6] Lewinson RT, Fukuchi CA, Worobets JT, Stefanyshyn DJ. The effects of wedged footwear on lower limb frontal plane biomechanics during running. Clin J Sport Med 2013;23:208–15.
Letter to the Editor
Ryan T. Lewinson ⁎ Darren J. Stefanyshyn Biomedical Engineering, Schulich School of Engineering, University of Calgary, Canada ⁎ Corresponding author at 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada E-mail address: [email protected] (R.T. Lewinson). 16 March 2015
259
Contents lists available at ScienceDirect
Contemporary Clinical Trials journal homepage: www.elsevier.com/locate/conclintrial
Letter to the Editor Losing control over control conditions in knee osteoarthritis orthotic research
Keywords: Control Biomechanics Footwear Knee osteoarthritis Gait
Wedged footwear orthotics/insoles have been studied extensively as a strategy to reduce the peak knee adduction moment (a measure of knee joint load) for individuals with knee osteoarthritis [1–3]. While consistent biomechanical efficacy has been found for wedged insoles [1], their clinical efficacy differs dramatically across studies [2]. Recently, Parkes et al. [2] published a meta-analysis where they proposed that different footwear control conditions used across studies could explain the differing clinical results. These authors advocated, on the basis of controlling placebo effects, that a flat insole within the participant's own shoe should be the control condition of choice for future trials. Certainly, placebo effects are an important consideration when designing a clinical trial; however, in the case of an intervention designed to alter knee joint loading, the primary objective for a control group should be ensuring that the groups' biomechanics remain unchanged relative to what they normally experience. This is analogous to drug trials, where researchers must ensure that the control condition is chemically inert. So in the case of a flat insole for knee osteoarthritis trials, do we know for certain that they are biomechanically inert at the knee, in the same way that we know a sugar-pill will not contain any active medication? Currently, no direct evidence is available to decisively answer this question; however, recent work by McCormick et al. [4] suggests that we should proceed with caution. Specifically, these researchers found that flat insoles can induce altered pressure distributions beneath the foot, which has been shown on numerous occasions to be correlated with a change in magnitude of the peak knee adduction moment [5,6]. Therefore, it is possible that previous studies utilizing a flat insole as a control condition may have actually induced altered knee biomechanics in the control group, consequently biasing study clinical outcomes.
http://dx.doi.org/10.1016/j.cct.2015.03.011 1551-7144/© 2015 Elsevier Inc. All rights reserved.
In light of the work by McCormick and colleagues [4], and contrary to the recommendations by Parkes et al. [2], we propose that currently, it is best to err on the side of caution and utilize the participants' own footwear as a control condition, thus ensuring the participants' biomechanics are unchanged relative to what they normally experience. This method does not directly account for placebo effects, so researchers will need to consider this when interpreting their results. For instance, if a positive effect of insoles is found over a control group where the participant's own footwear is used, we advise that researchers attempt to explain why this effect occurred. One approach may be to assess if a correlation exists in the insole group between the change in knee adduction moment induced by the insoles, and change in pain over the duration of the study — a significant correlation would indicate clinical benefits were related to a biomechanical change, and not exclusively attributed to placebo effects. It seems clear that there is an urgent need to invest time into studying what can serve as a proper footwear control condition for knee osteoarthritis trials. This will help to address biomechanical and placebo issues, and stimulate consistency in control conditions across trials. Acknowledgments RTL is funded by the Vanier Canada Graduate Scholarship program through the Canadian Institutes of Health Research, the Natural Sciences and Engineering Research Council of Canada CREATE Program, the Alberta Innovates-Health Solutions MD/PhD Program, and the Killam Trusts. References [1] Reeves ND, Bowling FL. Conservative biomechanical strategies for knee osteoarthritis. Nat Rev Rheumatol 2011;7:113–22. [2] Parkes MJ, Maricar N, Lunt M, LaValley MP, Jones RK, Segal NA, et al. Lateral wedge insoles as a conservative treatment for pain in patients with medial knee osteoarthritis: a meta-analysis. JAMA 2013;310:722–30. [3] Hinman RS, Bennell KL. Advances in insoles and shoes for knee osteoarthritis. Curr Opin Rheumatol 2009;21:164–70. [4] McCormick CJ, Bonnano DR, Landorf KB. The effect of customized and sham foot orthoses on plantar pressures. J Foot Ankle Res 2013;6:19. [5] Hinman RS, Bowles KA, Metcalf BB, Wrigley TV, Bennell KL. Lateral wedge insoles for medial knee osteoarthritis: effects on lower limb frontal plane biomechanics. Clin Biomech 2012;27:27–33. [6] Lewinson RT, Fukuchi CA, Worobets JT, Stefanyshyn DJ. The effects of wedged footwear on lower limb frontal plane biomechanics during running. Clin J Sport Med 2013;23:208–15.
Letter to the Editor
Ryan T. Lewinson ⁎ Darren J. Stefanyshyn Biomedical Engineering, Schulich School of Engineering, University of Calgary, Canada ⁎ Corresponding author at 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada E-mail address: [email protected] (R.T. Lewinson). 16 March 2015
259