Effects of Commercial Footwear on Pain, Disability in Gout
Effects of Commercial Footwear on Pain, Disability in Gout
This is the first intervention study examining the role of footwear in people with gout. In this study, most participants selected the Cardio Zip. We found that the Cardio Zip shoe significantly reduced foot pain, general pain and foot impairment over 8 weeks.
A number of features in the Cardio Zip shoe may be responsible for the reduction in pain and disability. The medial size zip closure in the Cardio Zip shoe enhances the ease of putting on and taking off the shoe. The Cardio Zip shoe also uses a dual-density midsole system to control motion. Barton reported that the motion control properties of footwear are considered an important shoe feature in the management of patients with RA and musculoskeletal injuries. Another feature of the Cardio Zip shoe that may have reduced foot pain was the use of gel cushioning in the heel and forefoot regions to improve shock attenuation. This shoe element was not present in the other three shoe types. Dufour reported that shoes that have softer out-soles, and mid-soles, or insoles that use elements of gel, foamed polyurethane, or air chambers can smooth (low pass filter) the shock wave associated with foot-strike. Finally, the Cardio Zip shoe midsole/outsole has a 'rocker' type system to create a smoother heel to toe transition during the gait cycle while maintaining both stability and comfort. Previous studies have reported that the toe rocker-soled shoe is thought to reduce pain by decreasing forefoot loading and promoting a normal heel-toe motion during gait. Cho reported that rocker-soled shoes with comfortable insoles may be enough to reduce foot pain and increase foot function for people with RA.
We found our participants wore the chosen shoes an average of 26 hours/week over the 8-week trial, demonstrating good adherence. Similar findings have been reported in RA studies using foot orthoses. Patient acceptability and adherence are integral components of treatment success with footwear or foot orthoses interventions. Williams also reported significant improvements in foot pain associated with RA when patients were involved in the choice of their shoes, as compared to having a particular shoe prescribed to them. Given the number of factors that influence shoe choice in people with gout, it would be important that patients are educated in the key elements/concepts that they should look for when buying shoes in the retail sector. In agreement with our previous findings, the majority of participants' own shoes would be regarded as old, and hence likely to be limited in their ability to control foot motion, and cushion the foot sufficiently.
We acknowledge that the study had limitations. The researcher collecting the outcome measures was not blinded to the shoes that the patient had chosen. However, the study protocol stated that the researcher should make no comments concerning the patient's choice. The period over which shoes were worn was short and the shoes could be considered as being in a relatively new state after 8 weeks wear. A longer study would allow greater understanding of the effects of wear on the structural and mechanical properties of materials responsible for motion control and shock absorption, and the influence of these properties on long-term pain reduction. The high frequency of tophaceous disease reflects the hospital setting and the complexity of gout seen in Auckland, New Zealand particularly in the Māori and Pacific people. This may limit the generalisability of the findings to other populations with gout. Furthermore, it is unclear whether people with different stages of the disease would benefit from a similar intervention with footwear. Using the self-reported diaries to assess adherence was patient-reported only and therefore may be susceptible to bias/error.
Discussion
This is the first intervention study examining the role of footwear in people with gout. In this study, most participants selected the Cardio Zip. We found that the Cardio Zip shoe significantly reduced foot pain, general pain and foot impairment over 8 weeks.
A number of features in the Cardio Zip shoe may be responsible for the reduction in pain and disability. The medial size zip closure in the Cardio Zip shoe enhances the ease of putting on and taking off the shoe. The Cardio Zip shoe also uses a dual-density midsole system to control motion. Barton reported that the motion control properties of footwear are considered an important shoe feature in the management of patients with RA and musculoskeletal injuries. Another feature of the Cardio Zip shoe that may have reduced foot pain was the use of gel cushioning in the heel and forefoot regions to improve shock attenuation. This shoe element was not present in the other three shoe types. Dufour reported that shoes that have softer out-soles, and mid-soles, or insoles that use elements of gel, foamed polyurethane, or air chambers can smooth (low pass filter) the shock wave associated with foot-strike. Finally, the Cardio Zip shoe midsole/outsole has a 'rocker' type system to create a smoother heel to toe transition during the gait cycle while maintaining both stability and comfort. Previous studies have reported that the toe rocker-soled shoe is thought to reduce pain by decreasing forefoot loading and promoting a normal heel-toe motion during gait. Cho reported that rocker-soled shoes with comfortable insoles may be enough to reduce foot pain and increase foot function for people with RA.
We found our participants wore the chosen shoes an average of 26 hours/week over the 8-week trial, demonstrating good adherence. Similar findings have been reported in RA studies using foot orthoses. Patient acceptability and adherence are integral components of treatment success with footwear or foot orthoses interventions. Williams also reported significant improvements in foot pain associated with RA when patients were involved in the choice of their shoes, as compared to having a particular shoe prescribed to them. Given the number of factors that influence shoe choice in people with gout, it would be important that patients are educated in the key elements/concepts that they should look for when buying shoes in the retail sector. In agreement with our previous findings, the majority of participants' own shoes would be regarded as old, and hence likely to be limited in their ability to control foot motion, and cushion the foot sufficiently.
We acknowledge that the study had limitations. The researcher collecting the outcome measures was not blinded to the shoes that the patient had chosen. However, the study protocol stated that the researcher should make no comments concerning the patient's choice. The period over which shoes were worn was short and the shoes could be considered as being in a relatively new state after 8 weeks wear. A longer study would allow greater understanding of the effects of wear on the structural and mechanical properties of materials responsible for motion control and shock absorption, and the influence of these properties on long-term pain reduction. The high frequency of tophaceous disease reflects the hospital setting and the complexity of gout seen in Auckland, New Zealand particularly in the Māori and Pacific people. This may limit the generalisability of the findings to other populations with gout. Furthermore, it is unclear whether people with different stages of the disease would benefit from a similar intervention with footwear. Using the self-reported diaries to assess adherence was patient-reported only and therefore may be susceptible to bias/error.
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