The evaluation of three treatments for plantar callus: a three-armed randomised, comparative trial using biophysical outcome measures

BACKGROUND: Callus is one of the most common foot skin complaints experienced by people of all ages. These painful and unsightly lesions often result in disability. The ‘gold standard’ of treatment is scalpel debridement by a trained specialist; however, people also seek over-the-counter remedies. There is a lack of clinical evidence for the efficacy of such products, which makes selection by patients and practitioners difficult. METHODS: This randomised, three-armed, parallel, comparative trial aimed to test the efficacy of two home treatments for plantar callus using novel, objective outcome measures (skin hydration using the capacitance method; elasticity using negative pressure application; and surface texture using imaging). Additional outcome measures were: size of callus, quality of life (Foot Health Status Questionnaire) and self-reported participant satisfaction and compliance. The results were compared to a podiatry treatment. Participants were randomly allocated to one of three groups: potassium hydroxide (KOH, 40 %); trichloroacetic acid (TCA); and podiatry treatment. Participants were followed for 3 weeks after their initial intervention appointment (days 7, 14 and 21). The primary outcomes were the change from baseline in callus hydration, elasticity, texture, and size at each of the three time points. The secondary outcomes where: change in quality of life 21 days after treatment; resolution of calluses via visual inspection; and participant compliance and perception. RESULTS: Forty-six participants (61 ft) with plantar calluses were recruited. The podiatry treatment showed immediate and significant changes in all objective outcomes, associated foot pain and function (p <0.01). Lesser changes in skin quality and perceived pain and functional benefits occurred with TCA and KOH over 21 days. CONCLUSIONS: This is the first study where objective outcome measures have been used to measure changes in the nature of skin in response to callus treatments. We found significant differences in plantar callus in response to podiatry and two home treatments. The podiatry treatment showed immediate and significant changes in skin and associated foot pain and function. Lesser, but sometimes comparable, changes in skin and perceived pain and functional benefits occurred with TCA and KOH over 21 days. TRIAL REGISTRATION: ISRCTN14751843: date of registration: 30 April 2015. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13063-016-1377-2) contains supplementary material, which is available to authorized users.