Humerus Lengthening with a Motorized Intramedullary Nail: A Systematic Review of Outcomes and Complications

Aim: In the past decade, internal limb lengthening nails have gained popularity. In this study, we aim to systematically review the literature on humerus limb lengthening with a motorized intramedullary nail (MIN). We intend to assess the outcome and complications of this technique. Materials and methods: A systematic review was performed in the following databases: PubMed, Embase, Web of Science, and the Journal of Limb Lengthening and Reconstruction. The inclusion criteria included limb lengthening of the humerus using an intramedullary nail, clinical studies, all levels of evidence, and no restriction to the date of publication. Results: Our search yielded 239 journal articles. A total of nine articles remained relevant based on the inclusion and exclusion criteria. The total number of patients was 20, with 22 segments lengthened. The mean age of the patients was 20.8-year-old [standard deviation (SD), 12.0; range, 13-51]. The mean gained length was 5.7 cm (SD, 0.9; range, 5-7.5) with a mean distraction protocol of 0.82 mm/day (SD, 0.2; range, 0.6-1). The average duration of lengthening was 71.6 days (SD, 12.8; range, 50-93), and the mean duration of consolidation was 192.3 days (SD, 40.5; range, 120-228). Reported complications included a range of motion (ROM) limitation, hardware failure, and hypertrophic bone regeneration. Conclusion: Humeral lengthening with an MIN provides favourable outcomes with low complication rates. Future high-level studies should focus on comparing long-term outcomes of humeral lengthening utilising internal and external fixation techniques. Clinical significance: Humeral lengthening using MIN can be used safely. Each surgical approach and type of nail have different risks and benefits. These should be carefully discussed when planning the surgery.