Intramedullary medial column support with the Midfoot Fusion Bolt (MFB) is not sufficient for osseous healing of arthrodesis in neuroosteoarthropathic feet.

INTRODUCTION: To address midfoot instability of Charcot disease a promising intramedullary implant has recently been developed to allow for an arthrodesis of the bones of the medial foot column in an anatomic position. We report on a group of patients with Charcot arthropathy and instability at the midfoot where the Midfoot Fusion Bolt had been employed as an implant for the reconstruction of the collapsed medial foot column.

MATERIAL AND METHODS: A total of 7 patients (median age 56.3 years, range 47-68) were enrolled with severe Charcot deformation at Eichenholtz stages I-II (Sanders and Frykberg types II and III). The medial column was stabilised primarily with an intramedullary rod (Midfoot Fusion Bolt) in stand-alone technique in order to reconstruct the osseous foot geometry. The bolt was inserted in a retrograde mode via the head of MTI and forwarded into the talus. Follow-up time averaged 27 months (range 9-30).

RESULTS: Intraoperative plantigrade reconstruction and restoration of the anatomic foot axes of the medial column was achieved in all cases with the need for revision surgery in 6 out of 7 patients due to soft tissue problems (2 impaired wound healing, 1 postoperative haematoma, 3 early infection). Implant-associated problems were seen in one case intra-operatively with fracture of the first metatarsal shaft and two cases with implant loosening of the MFB and need for implant removal during long time follow-up. Two patients underwent lower leg amputation due to a progressive deep soft tissue infection. One patient healed uneventfully without need for revision surgery. Except for one case recurrent ulcerations were not observed, so far.

CONCLUSION: Medial column support in midfoot instability of Charcot arthropathy with a single intramedullary rod does not provide enough stability to achieve osseous fusion. MFB loosening was associated with deep infection in a majority of our cases. To prevent early loosening of the intramedullary rod and to increase rotational stability, additional implants as angular stable plates are needed at the medial column and eventually an additional stabilisation of the lateral foot column where manifest instability exists at the time of primary surgical intervention.