Absence of Peroneus Tertius in Split Anterior Tibialis Tendon Transfer Surgery.

Split anterior tibialis tendon transfer is a common orthopedic surgical procedure for varus foot deformities. In the absence of the peroneus tertius, the peroneus brevis may be used in the transfer. Little is known about the prevalence of each transfer type. The goal of this study is to understand trends in tendon transfer for patients who undergo split anterior tibialis tendon transfer. Records of all patients who underwent tibialis anterior tendon split transfer at our institution between January 2004 and September 2020 were reviewed. After, 337 subjects who underwent tibialis anterior tendon split transfer were included. The peroneus tertius was absent in 33.2% (112/337) of subjects. Logistic regressions showed the odds of having a missing peroneus tertius were 66.9% lower for subjects with cerebral palsy and related etiologies (odds ratio [OR]: 0.331, 95% confidence interval [CI]: 0.21, 0.53), 47% lower for white subjects (OR: 0.53, 95% CI: 0.31, 0.91), and 59.1% lower for non-Hispanic subjects (OR: 0.409, 95% CI: 0.25, 0.66). The odds of a missing peroneus tertius tendon were 2.72 times higher for subjects who identified in the other racial category (95% CI: 1.65, 4.49), and 2.41 times greater for subjects who identified as Hispanic (95% CI: 1.51, 3.84). Patients who underwent the procedure who identified as Hispanic or members of other (non-White, -Black, -Asian) racial groups had an increased likelihood of having a missing peroneus tertius tendon. Patients who identified as white, having cerebral palsy or related etiologies, or non-Hispanic had a decreased risk of having a missing peroneus tertius tendon.