Outcomes and Complications of First Tarsometatarsal Plantarflexion Bone Block Arthrodesis With a Precontoured Allograft Wedge.

BACKGROUND

Instability and collapse of the medial longitudinal arch and structural incompetence of the first ray have been linked to various conditions of the foot. These include progressive collapsing foot deformity (PCFD), hallux valgus (HV), and midfoot osteoarthritis (OA). More recently, an innovative approach combining the biomechanical advantages of the modified Lapidus procedure and Cotton osteotomy were described in the literature. The aim of this study was to determine the midterm outcomes following first-tarsometatarsal plantarflexion bone block arthrodesis with a precontoured allograft wedge (first-TMT PFBB arthrodesis).

METHODS

A retrospective review was performed of consecutive patients who underwent this procedure between 2020 and 2023 with an average 2-year follow-up. Patients were assessed for radiographic union/nonunion based on weightbearing CT (WBCT) by 3 independent fellowship-trained orthopaedic foot and ankle surgeons. Patient-reported outcomes (PROs) including Patient-Reported Outcome Measures Information System (PROMIS) and Foot and Ankle Ability Measure (FAAM) activities of daily living (ADL) were collected pre- and postoperatively. Patients were excluded if diagnosed with Charcot arthropathy/neuropathy or underwent an extended medial column arthrodesis.

RESULTS

A total of 61 patients were identified as having a first-TMT PFBB arthrodesis procedure, 49 patients (52 feet) met inclusion criteria. The average allograft wedge was 9 mm (range, 5-14) mm. Fourteen feet (26.9%) underwent at least 1 revision surgery. Nonunion occurred in 22 feet (42.3%) in 40.8% of patients. Additionally, new-onset plantar first-MTP/sesamoid overload pain occurred in 8 feet (15.4%).

CONCLUSION

Given the observed high nonunion rate (42%) and revision rate (27%), this technique should be approached with caution. We believe patient selection and counseling regarding potential postoperative complications including high reoperation and nonunion rates as well as the potential to overlengthen or overcorrect first-ray positioning resulting in sesamoid overload symptoms are important to consider before proceeding with first-TMT plantarflexion allograft bone block arthrodesis.