Technical considerations and early results of magnetic compressive intramedullary nailing for humeral shaft delayed unions and nonunions

BACKGROUND: Expandable magnetic rods and intramedullary nails are being used in a number of innovative ways, including limb length discrepancy and scoliosis correction. However, recently, the full complement of these devices has been further explored, with the utilization of their compressive capacity to improve fracture healing. The purpose of the present study was to report on early results of compressive magnetic intramedullary nailing for humeral shaft delayed unions and nonunions. METHODS: This retrospective case series was completed at a level 1 trauma center, with adult patients who underwent compressive intramedullary nailing from 2017 to 2021 for humeral shaft nonunion or delayed union. The primary indication for this procedure was nonunion in the setting of previous conventional fixation, but a subset of patients with atrophic nonunions and risk factors for recalcitrant nonunion were also included. RESULTS: Fourteen patients, with a mean age of 51 ± 17 years, underwent compressive magnetic intramedullary nailing. Nine patients had previously underwent surgery, 6 of which had undergone multiple prior procedures. Five others were initially treated nonoperatively and underwent surgery 4.1 ± 2.9 months out from injury. Ten patients went on to union at a mean of 2.9 ± 2.4 months. One patient experienced hardware failure with nail cut-out at 2 weeks, and one required revision surgery for a wound infection. Three other patients were lost to follow-up, one of which was deceased for reasons unrelated to surgery. CONCLUSION: Compressive magnetic intramedullary nails are a viable solution for complex humeral shaft nonunions, particularly in the setting of previously well-fixed fractures and those at risk of recalcitrant nonunion. However, comparative and prospective studies looking at union rates and secondary procedures are needed to more clearly define their role in treatment and assure their safety, given recent concerns regarding osteolysis at the nail modular junction.