Bone-block arthrodesis procedure in failures of first metatarsophalangeal joint replacement

Abstract

Background: The treatment for the failure of a first metatarsophalangeal joint (MTP1) prosthesis can be complex. There is no consensus regarding the ideal treatment. One of the main issues is the available bone stock after prosthesis removal. The aim of the study was to report the clinical and radiographic results for MTP1 arthrodesis with autologous calcaneus bone graft (bone-block fusion) as a revision procedure of a previous MTP1 implant failure.

Methods: This study included 12 patients diagnosed with failure of a MTP1 prosthesis. All patients were treated with MTP1 arthrodesis using ipsilateral calcaneal bone graft. Patients were evaluated with the Foot Ankle Disability Index (FADI), the visual analogue pain scale (VAS) and AOFAS Hallux Metatarsophalangeal Interphalangeal scoring system (AOFAS-HMI), weight-bearing radiograph of the foot, and a computed tomography scan. The 1-2 intermetatarsal angle, hallux valgus angle, and first ray length were measured before surgery and at final follow-up.

Results: Complications included 3 cases of arthrodesis nonunion, (1 symptomatic, 2 asymptomatic) with 2 of the 3 patients experiencing hardware failure and 1 superficial wound infection. The average FADI improved from 41.8 preoperatively to 84.6 at final follow-up (p<0.05); the average VAS improved from 8.5 preoperatively to 2 at final follow-up (p<0,05); the average AOFAS-HMI significantly improved from 50.7 preoperatively to 73.8 at final follow-up (p<0.05). The average length of the bone-block used was 14.3mm (range 11-19mm). The 1-2 intermetatarsal angle decreased from 9.5° preoperatively to 8.4° at final follow-up (p<0.05); hallux valgus angle improved from 19.7° preoperatively to 14.3° at final follow-up (p<0.05).

Conclusions: The management of a failed first metatarsophalangeal joint prosthesis remains controversial. Bone-block arthrodesis using ipsilateral calcaneal autograft appears to be a viable option restoring the bone loss, and avoiding hallux shortening. Nonunion is the most frequent complication with 25% of patients affected, but only 1/3 of patients with nonunion were symptomatic and required revision.

Keywords: Bone-block arthrodesis; Calcaneus bone-block; MTP1 arthrodesis; MTP1 implant failure; MTP1 joint replacement; MTP1 joint replacement failure.