Radiographic factors associated with painful callosities after forefoot surgery in patients with rheumatoid arthritis

Objectives Operative procedures for rheumatoid forefoot deformities have gradually changed from arthrodesis or resection arthroplasty to joint-preserving surgery. Although joint-preserving arthroplasty has yielded good outcomes, painful plantar callosities may occur post-operatively. This study aimed to reveal the radiographic factors associated with painful callosities after joint-preserving surgery for forefoot deformities in patients with rheumatoid arthritis (RA). Methods We retrospectively evaluated 166 feet in 133 patients with RA who underwent forefoot joint-preserving arthroplasty, including proximal rotational closing-wedge osteotomies of the first metatarsal, between January 2012 and December 2015. Logistic regression analysis was performed with the objective variable set as the presence/absence of painful plantar callosities at the final observation and the explanatory variables set as several radiographic factors, including post-operative relative first metatarsal length (RML), amount of dorsal dislocation of the fifth metatarsal (5DD), and arc failure of the lesser toes. Results At the final follow-up, 42 of the 166 feet (25.3%) had painful callosities under the metatarsal heads post-operatively. Logistic regression analysis showed that the RML, 5DD, and lesser toes' arc failure were significantly associated with painful callosities. Conclusions We identified that RML, 5DD, and arc failure of the lesser toes were associated with painful plantar callosities after the surgery.