[Application of nickel-titanium shape memory staples in treatment of multiple metatarsal fractures].

Objective: To investigate the effectiveness of nickel-titanium shape memory staples in treating multiple metatarsal fractures.

Methods: The clinical data of 27 patients with multiple metatarsal fractures who were treated between January 2022 and June 2023 and met the selection criteria were retrospectively analysed. The cohort consisted of 16 males and 11 females, aged 33-65 years (mean, 47.44 years). The causes of injury included heavy object impact in 11 cases, traffic accidents in 9 cases, and crush in 7 cases. Simultaneous fractures of 2, 3, 4, and 5 bones occurred in 6, 6, 4, and 8 cases, respectively, with tarsometatarsal joint injury in 3 cases. Fixation was performed using staples for 16, 22, and 9 fractures in the metatarsal neck, shaft, and the base, respectively, and 5 tarsometatarsal joint injuries. Preoperative soft tissue injuries were identified in 8 cases and classified according to the Tscherne-Oestern closed soft tissue injury classification as type Ⅰ in 5 cases and type Ⅱ in 3 cases. One case of type Ⅱexhibited preoperative skin necrosis. The patients were treated with fixation using nickel-titanium shape memory staples. Complications and fracture healing were documented. At last follow-up, the American Orthopaedic Foot and Ankle Society (AOFAS) forefoot score was used to evaluate the function, and the visual analogue scale (VAS) score was used to evaluate the pain.

Results: The 27 patients were followed up 9-19 months (mean, 12.4 months). Postoperative X-ray films revealed no loss of fracture reduction, and all fractures achieved bony union. No internal fixator loosening, breakage, or other mechanical failures was observed. The mean fracture healing time was 3.13 months (range, 3-4 months). Postoperatively, 4 cases (2 of Tscherne-Oestern type Ⅰ, 2 of type Ⅱ) developed superficial skin necrosis, which resolved with dressing changes. No infection was observed in the remaining patients, and all wounds healed. At last follow-up, the AOFAS forefoot score ranged from 70 to 95, with an average of 86.6, of which 19 cases were excellent, 6 cases were good, and 2 cases were fair, with an excellent and good rate of 92.6%; the VAS score ranged from 0 to 3, with an average of 0.9, of which 24 cases were excellent, and 3 cases were good, with an excellent and good rate of 100%.

Conclusion: The use of nickel-titanium shape memory staples in the treatment of multiple metatarsal fractures can effectively protect local skin and soft tissues and minimize secondary damage associated with internal fixator insertion. It is a viable surgical option for management of multiple metatarsal fractures.