Opposition is an essential function of the human thumb to enable fine pinch and grip strength. Loss of opposition can be caused by both congenital and acquired pathology resulting in significant disability. This systematic review aims to compare the different techniques available to restore opposition. A systematic review of opponensplasty techniques was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines using PubMed, Embase, Medline, and Web of Science. Studies published in English before April 2021 and that reported on original outcomes of opponensplasty techniques used in the context of neurologic dysfunction were eligible for inclusion. A total of 641 articles were included, of which 42 texts were eligible for inclusion with a total cohort of 873 patients. The most commonly used transfers were palmaris longus (PL), extensor indicis proprius (EIP), and flexor digitorum superficialis (FDS). These transfers all demonstrated an improvement in range of motion, pinch strength, and Kapandji scores. Complication rates of 19% and 12% were reported with FDS and EIP transfers, respectively, predominantly related to donor site morbidity. A complication rate of 6% was observed with PL transfers, which was most commonly related to bowstringing. Heterogeneity of outcomes precluded a direct statistical comparison. There is significant heterogeneity in the literature reporting on opponensplasty techniques. There is limited capacity of direct comparison; however, FDS and EIP appear to demonstrate better functional outcomes, at the cost of higher complication rates. Each technique has specific complications and advantages and importance in patient counseling and discussion. Further prospective comparative studies are warranted.
Keywords: hand; nerve injury; soft tissue reconstruction; tendon; trauma.