Case report of iatrogenic synostosis following foot surgery and the subsequent management plan

Abstract

Common complications after distal metatarsal minimally invasive osteotomy (DMMO) include prolonged edema post-surgery, delayed union, transfer metatarsalgia, floating toe, persistent pain, neurovascular injury and wound complications. Synostosis following DMMO has not been reported as a complication before. Previously, synostosis in the foot has been reported as a complication following surgical drainage of an infected plantar ulcer in a patient with diabetic foot. The surgical drainage was carried out via both plantar and dorsal incisions. This patient then subsequently had synostosis between the metatarsal heads and proximal phalanges of the first and second toes. As such, the aim of this case report is to report a rare complication of synostosis following DMMO involving the 2nd and 3rd toes of the same foot, describing the subsequent clinical presentation of the patient and the surgical management of the complication as well as the patient’s recovery following surgery.

Introduction

Previously, synostosis in the foot has been reported as a complication following surgical drainage of an infected plantar ulcer in a patient with diabetic foot. The surgical drainage was carried out via both plantar and dorsal incisions. This patient then subsequently had synostosis between the metatarsal heads and proximal phalanges of the first and second toes.

As such, the aim of this study is to report a rare complication of synostosis following DMMO involving the 2nd and 3rd toes of the same foot, describing the subsequent clinical presentation of the patient and the surgical management of the complication as well as the patient’s recovery following surgery.

Case report

A 76-year-old male patient presented to the foot and ankle clinic in October 2025 with pain over the plantar aspect of his left foot over the 3rd metatarsal head. His symptoms had been ongoing for 2 to 3 months and his pain was exacerbated by ambulation.

Of note, this patient had been presented to the foot and ankle clinic before in May 2024 with long-standing left foot pain and toe deformities. He also had difficulties with footwear.

Back in 2024, he was examined and noted to have severe hallux valgus, stiff range of motion of the 1st metatarsophalangeal joint (MTPJ), positive axial loading of the 1st MTPJ, 2nd and 3rd toe claw deformities with chronic dislocation of the 2nd and 3rd MTPJ of his left foot.

X-rays of his left foot were performed ( Figs. 1 and 2 ). His diagnosis was that of left foot 1st MTPJ OA with hallux valgus, left 2nd and 3rd toe claw toe deformities. He was counselled regarding conservative and surgical options. In view of his long-standing symptoms affecting his uality of life, patient opted for surgical intervention.

The patient then underwent left foot 1st MTPJ fusion, left 2nd and 3rd toe DMMO and left 3rd toe proximal phalanx minimally invasive osteotomy on 16 May 2024. For the 1st MTPJ fusion, a dorsal plate and a single compression screw was applied via a dorso-medial incision over the left 1st MTPJ. For the lesser toe deformities, stab incisions were made over the left 2nd and 3rd webspace. A MIS (minimally invasive) burr was used to perform the left 2nd and 3rd toe DMMO as well as the left 3rd toe proximal phalangeal osteotomy. The claw toe deformities were corrected and held in place with 2 K-wires. A backslab was applied and the patient was kept non-weight bearing for 4 weeks. Non-weight bearing X-rays of his left foot were then performed on post-operative day 1 ( Figs. 3 and 4 ).

Post-operatively, patient recovered well. He was discharged on post-operative day 1. His wounds healed well. Sutures were removed at 3 weeks post-op. K-wires were removed at 4 weeks post-op. X-rays of his left foot were repeated at 4 weeks post-op ( Figs. 5 and 6 ). X-rays showed satisfactory alignment of the left big toe and 2nd toe. There was slight angulation of the 3rd toe. The patient was then allowed to weight bear as tolerated with darco shoes.