Replacement of the first metatarsophalangeal joint with a Swanson implant accompanied by open-wedge osteotomy of the first metatarsal bone for hallux valgus in rheumatoid arthritis.

Hallux valgus is very common in rheumatoid arthritis (RA) and mostly accompanied by varus deformity of the first metatarsal bone, which is often corrected in surgeries for hallux valgus in nonarthritic condition, but rarely in RA. We performed the replacement of the first metatarsophalangeal (MTP) joint with a Swanson hinge toe implant accompanied with open-wedge osteotomy of the first metatarsal bone, aiming at reconstruction of a functioning first MTP joint without recurrence of hallux valgus. Fifteen feet of 11 patients with RA were studied with a mean follow-up period of 45.1 months. The American Orthopaedic Foot and Ankle Society (AOFAS) scale improved significantly from 39 points preoperatively to 81.7 at the last follow-up. The hallux valgus angle (HVA), angle between the first and second metatarsal bones (M1/2), and that between the first and fifth (M1/5), measured on standing anteroposterior radiographs, decreased significantly from 49.8 degrees, 16.7 degrees, and 34.4 degrees preoperatively to 10.9 degrees, 8.7 degrees, and 22.2 degrees at the last follow-up, respectively. Union of the corrected first metatarsal bone was recognized in all cases and no such problems as infection, dislocation, or implant fracture were observed. These data suggest that replacement of the first MTP joint with a Swanson implant accompanied with open-wedge osteotomy of the first metatarsal bone can be a useful option for hallux valgus in RA.