Functional outcomes after tendon transfers in upper extremity reconstruction: A comprehensive systematic review

This systematic review examines the effect of functional outcome on tendon transfer in upper extremity reconstruction, considering motor aspects, strength, range of motion (ROM), patient-reported outcomes (PRO), and psychosocial outcomes. We used PubMed, Embase, Cochrane Library, Scopus, Web of Science, and CINAHL databases and, consistent with PRISMA guidelines, searched these databases until July 2025 with randomized controlled trials, cohort studies, and case series (>=10 patients) in all ages and causes (traumatic, neurological, congenital, degenerative). Exclusion criteria included case reports, studies of <10 patients, or non-upper extremity transfers. Studies were screened, and two reviewers extracted data on study characteristics, patient demographics, surgical techniques, and outcomes (MRC scale, dynamometry, goniometry, DASH, SF-36, and return-to-work status). Bias was assessed using the Cochrane and Newcastle-Ottawa tools. Subgroup analyses were by region of anatomical involvement (shoulder, elbow, wrist, hand), etiology, age, and socioeconomic situation (if a sufficient number of studies permitted it). Comparisons were made to alternatives (i.e., nerve transfers). Among the main findings, differences in functional recovery can be observed in patient factors (such as age and compliance), surgical practice, and access to rehabilitation. Severe outcomes (tendon rupture, etc.) were studied. In the review, research limitations are identified, highlighting gaps that provide evidence-based guidance to clinicians and inform future strategies for advancing upper extremity reconstruction.