The effectiveness of salicylic acid plasters compared with ‘usual’ scalpel debridement of corns: a randomised controlled trial

BACKGROUND Corns are a common foot problem and surveys have indicated that between 14-48% of people suffer from them. Many of these will seek podiatry treatment, however there is little evidence to indicate which current treatments provide long term resolution. This study compared 'usual' treatment (enucleation with a scalpel) with the application of 40% salicylic acid plasters to corns to investigate which is the most effective in terms of clinical, economic and patient-centred outcomes. METHODS A parallel-group randomised controlled trial was carried out in two centres where adults who presented with one or more corns and who met the inclusion criteria were allocated to either 'usual' scalpel debridement or corn plaster treatment. All participants had measurements of corn size, pain using a 100 mm visual analogue scale (VAS) and health-related quality of life (EQ-5D) measures by an independent podiatrist, blind to treatment allocation at baseline, 3, 6, 9 and 12 months. RESULTS 202 participants were randomised to receive scalpel debridement or corn plaster treatment (101 in each group). At 3 months 34% (32/95) of corns had completely resolved in the corn plaster group compared with 21% (20/94) in the scalpel group (p = 0.044), and 83% (79/95) had reduced in size in the corn plaster group compared with 56% (53/94) in the scalpel group (p < 0.001). At 12 months, time to corn recurrence was longer in the corn plaster group (p < 0.001). Pain from the corns was significantly lower in the corn plaster group at 3 months (p < 0.001) and EQ-5D scores changed (improved), from baseline, by 0.09 (SD ±0.31) and 0.01 (SD ±0.25) points in the corn plaster and scalpel groups respectively (p = 0.056). By month 12, EQ-5D scores had changed by 0.12 and -0.05 in the corn plaster and scalpel groups respectively (p = 0.005). The EQ-5D, VAS scores and the four domains of the Foot Disability Scale were similar in both groups at 3 and 12 months. The economic analysis indicated that corn plasters were a cost effective intervention. CONCLUSIONS The use of corn plasters was associated with a higher proportion of resolved corns, a prolonged time to corn recurrence, less pain and reduced corn size over the first 6 months in comparison with 'usual' scalpel treatment and this intervention was cost effective. Used under supervision of a podiatrist on appropriate patients, corn plasters offer an effective alternative to scalpel debridement.