Effectiveness of saline water and lidocaine injection treatment of intractable plantar keratoma: a randomised feasibility study

BACKGROUND: An intractable plantar keratoma (IPK) is a conical thickening of the epidermis’ stratum corneum and a common cause of foot pain which can have a significant, detrimental impact on the mobility, quality of life and independence of individuals. Conservative treatments are currently offered to patients with IPK, but they are unsatisfactory since they do not offer a sufficient or permanent reduction of symptoms. The purpose of this study was the evaluation of the feasibility, safety and effectiveness of innovative treatments for intractable plantar keratoma (IPK). METHODS: A randomized single blind trial with 40 patients divided with block randomization in four parallel groups was conducted to compare treatment combinations: conservative sharp debridement only or sharp debridement with needle insertion, physiological water injection or lidocaine injection. All patients obtained the same treatment four times at a four-week interval. At each visit, visual analog scale (VAS), Foot Function Index (FFI) and IPK size were evaluated. VAS and FFI were also completed at a six and twelve-month follow-up. RESULTS: Our findings in regards to feasibility demonstrated recruitment challenges because of the anticipated pain that would be provoked by needle insertion may not be worth the potential pain relief compared to debridement alone from the patient’s perspective. This was also the principal cause of drop out. Our preliminary results show no main effect of group for any of the clinical outcomes: pain felt on VAS, FFI score, IPK’s size (p > 0.05). However, the analysis revealed a statistically significant effect of time on VAS (p < 0.001), FFI score (p < 0.001) and IPK’s size (width and depth (p < 0.001); length (p = 0.001)), but no group x time interaction was found (p > 0.05). CONCLUSIONS: This study demonstrates that IPK treatment consisting of sharp debridement with needle insertion, physiological saline water injection or lidocaine injection is feasible and safe. There was a non-statistically significant trend toward diminishing pain intensity compared to scalpel debridement alone. The pain provoked by needle insertion and injection treatments must be addressed with a scientifically proven protocol to make it more comfortable for patients before these treatments could be considered in further studies. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04777227. 2 March, 2021 - Retrospectively registered (All participants were recruited prior to registration). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13047-021-00467-7.