Background In rheumatoid arthritis (RA) patients, (1) hallux MTP-joint arthroplasty (Swanson implant)+2^nd-5^th toes metatarsal head resection arthroplasty and (2) hallux Scarf osteotomy+2-5^th toes metatarsal shortening osteotomy are both standard methods.

Objectives The objective of this study is to investigate the unknown difference of operation (1) and (2) on plantar pressure distribution during walking.

Methods 3-feet of healthy volunteer (3 male / age 44.7y / body mass index [BMI] 20.2kg/m²), 12 feet of RA patients with operation (1) (3 male 9 female / age 62.4y / postoperation duration 6.8y / standing leg-heel angle [S-LHA]1.3° / BMI 20.8kg/m²), and 13 feet of RA patients with operation (2) (13 female / age 62.0y / postoperation duration 3.9y / S-LHA 0.5° / BMI 20.4kg/m²) were enrolled. Average plantar pressure during walking through 2^nd to 6^th steps was assessed by F-SCANⅡ® (Tekscan Inc.).

Results There was no significant difference in age, postoperation duration, S-LHA, and BMI between group (1) and (2). Plantar pressure distribution of hallux MTP-joints was 13.1% in healthy volunteer / operation (1) 7.0% / operation (2) 10.6%, and was significantly small in operation (1) compared to healthy volunteer (P<0.001) and to operation (2) (P<0.01). On the other hand, Plantar pressure distribution of 2^nd-5^th toes MTP-joints was 19.2% in healthy volunteer / operation (1) 20.4% / operation (2) 12.4%, and was significantly small in operation (2) compared to healthy volunteer and to operation (1) (P<0.01).

Conclusions Swanson implant arthroplasty of hallux MTP-joints may decrease plantar pressure distribution of MTP-joints compared to hallux Scarf osteotomy, and 2-5^th toes metatarsal head resection arthroplasty may increase plantar pressure distribution of MTP-joints compared to 2-5^th toes metatarsal shortening osteotomy.

Disclosure of Interest None Declared