Supination torque following single- versus double-incision repair of acute distal biceps tendon ruptures

Compared with single-incision (SI) distal biceps repair, double-incision (DI) repair has been described as permitting a more anatomic repair. We hypothesized that DI repair would result in greater terminal supination torque compared with SI repair for acute distal biceps ruptures.

Patients were included if they sustained an isolated, acute distal biceps rupture repaired between January 2012 and December 2017. Isometric forearm supination torque in 4 positions was measured using a validated uniaxial torque-testing device. Testing took place at least 12 months from surgery. The primary outcome was supination torque in the 60° supinated position. Secondary outcomes included supination torque in other forearm positions and functional outcome scores.

The study included 37 patients: 15 underwent repair with the DI technique and 22 with the SI technique. The mean age was 47.3 years, the median follow-up time was 28.1 months, and demographic data were similar between cohorts. Mean supination torque, relative to the unaffected side, was 61% (95% confidence interval, 45%-77%) for DI repair vs. 80% (95% confidence interval, 69%-92%) for SI repair in the 60° supinated position (P = .036). In a multivariable linear regression model controlling for arm dominance, age, follow-up time, and workers' compensation status; SI repair was associated with greater mean supination torque than DI repair by 20% (P = .015).

Contrary to our hypothesis, we found a 20% mean improvement in terminal supination torque for acute distal biceps ruptures repaired with the SI technique compared with the DI technique. This finding may have clinical significance for the more discerning, high-demand patient.