Association between preoperative pain intensity of MTP joint callosities of the lesser toes and fore-mid-hindfoot deformities in rheumatoid arthritis cases.

OBJECTIVES: To determine whether preoperative pain intensity in callosities of the lesser toe metatarsopharangeal (MTP) joint was associated with the grade of fore-mid-hindfoot deformities, because rheumatoid arthritis (RA) foot deformity includes the whole part of foot, and curiously differences between cases in the pain intensity of MTP joint callosities are often observed. METHODS: We evaluated 24 feet that had undergone forefoot surgery [August, 2014 - December, 2015] for painful lesser toe MTP joint deformity (callosities) in RA cases. A preoperative self-administered foot evaluation questionnaire (SAFE-Q) and pressure distribution information for foot function were also investigated. X-rays of the whole lower extremities and foot at weight-bearing were used to check fore-mid-hindfoot deformities. RESULTS: Group M (mild) [n = 9] included patients with the pain visual analog scale (VAS) less than 40 mm, while group S (severe) [n = 15] included patients whose VAS was over 40 mm. Group M showed stronger hindfoot valgus and pronated (abducted) deformity, and group M showed higher pressure on the first MTP joint compared with group S. CONCLUSIONS: These observations reconfirm that hindfoot valgus deformity and/or pronated (abducted) foot deformity affects the forefoot loading distribution, subsequently the pain of callosities in lesser toe MTP joints could be decreased.