First dorsal interosseous muscle reconstruction: a systematic review of its attachments

PurposeThe first dorsal interosseous (FDI) muscle, when impaired due to traumatic injuries or degenerative conditions, can be reanimated in various ways to restore pinch grip. These reconstructive techniques are planned based on a precise anatomical understanding of the FDI muscle. However, a review of the existing literature has brought to light controversy regarding its insertions. A systematic review of these descriptions is presented to appreciate these variations.MethodsAn electronic database search without exclusion by publication year and language was performed according to the Checklist for Anatomical Reviews and Meta-Analyses (CARMA) guidelines, using the PubMed, Scopus, Web of Science and Embase databases. An assessment of the methodological quality was performed.ResultsThirteen studies were included in this article. There is general agreement that the FDI muscle contains two bellies and a bony insertion into the index finger proximal phalanx base. However, due to wide anatomic variation, differences were reported on whether there is a soft tissue insertion. When this was found, the included studies differed on how commonly this occurs (between 1.4% and 78%), where it inserts. Other sites of distal insertions reported include the metacarpophalangeal capsule, the interosseous hood and an assemblage nucleus on the volar plate.ConclusionsOur systematic review, focusing on the insertion of the FDI muscle, summarizes the existing knowledge on its anatomy and variations, thereby facilitating better understanding of its function and surgical planning for reconstruction.