Systematic review on outcome of free functioning muscle transfers for elbow flexion in brachial plexus injuries

Elbow flexion is widely regarded as the most important function to restore in brachial plexus injuries. Free functioning muscle transfer surgery is indicated in patients with delayed presentation or failure of other primary procedures. Results of the transfer surgeries have been reported in the form of case series, but no further studies are available. This systematic review aims to provide a deeper understanding of this complex surgery and consists of 19 articles that include 364 patients. Data on injury characteristics, surgical techniques, complications as well as outcome measures were analysed. Our results show that functional muscle transfer for elbow flexion enables 87% and 65% of patients to achieve a useful power grade of ≥ 3 and ≥ 4, respectively, although other important outcome factors should be considered.