Introduction: Linburg-Comstock variation often connecting the flexor pollicis longus and flexor digitorum profundus of the index finger at a different level with significant discrepancy between clinical and cadaveric frequencies reported in the literature. Although this variation is quite prevalent, it is yet frequently unrecognized. The aim of this meta-analysis is to generate more accurate weighted frequency values of the Linburg-Comstock variation and to look for possible association with ethnicity, laterality, gender and side.
Methods: A systematic literature search identified 14 studies, including 4132 forearms/hands, which met the inclusion criteria.
Results: While no significant difference was found for laterality, we found significantly higher Linburg-Comstock variation rate in females compared to males. Turkish population demonstrated a significantly higher crude frequency when compared to Europeans (22.2 vs. 15.2%). Hispanic population showed the highest crude frequency (34.5%), whereas the African ancestry showed the least one (8.8%).
Conclusions: Linburg-Comstock variation could cause career-threatening disabilities and could complicate some hand injuries as well. This review invites future researchers to use a single nomenclature; the term "Linburg-Comstock variation" is to be used when no symptoms are present, and the term "Linburg-Comstock syndrome" in cases where the variation is symptomatic.
Keywords: Flexor digitorum profundus; Flexor pollicis longus; Hand; Linburg–Comstock variation; Meta-analysis.