Abstract
Compared to single-incision distal biceps repair (SI), double-incision repair (DI) theoretically allows for reattachment of the tendon to a more anatomically favorable position. We hypothesized that DI repair would result in greater terminal supination torque compared to SI repair for acute distal biceps ruptures.
In this retrospective cohort study, patients were included if they sustained an isolated, acute (° supinated position. Secondary outcomes included supination torque in 45° supinated, neutral, and 45° pronated positions, ASES elbow score, DASH, SF-12, and VAS. Power analysis revealed that at least 32 patients were needed to detect a minimum 15% difference in the primary outcome (β = 0.20). Statistical analysis was performed with significance level α = 0.05 using R version 3.4.1 (R Core Team 2017, Vienna, Austria).
Of 53 eligible patients, 37 consented to participate. Fifteen were repaired using DI technique and 22 using SI technique. Mean age was 47.3yrs and median follow-up time was 28.1months. The groups did not differ with respect to age, time-to-follow-up, dominance of arm affected, Workers Compensation or smoking status. Mean supination torque, measured as the percentage of the unaffected side, was 60.9% (95%CI 45.1–76.7) for DI repair versus 80.4% (95%CI 69.1–91.7) for SI repair at the 60°supinated position (p=0.036). There were no statistically significant differences in mean supination torque at the 45°supinated position: 67.1% (95%CI 49.4–84.7) for DI versus 81.8% (95%CI 72.2–91.4) for SI (p=0.102), at the neutral position: 88.8% (95%CI 75.2–102.4) for DI versus 97.6% (95%CI 91.6–103.7) for SI (p=0.0.170), and at the 45°pronated position: 104.5% (95%CI 91.1–117.9) for DI versus 103.4 (95%CI 97.2–109.6) for SI (p=0.0.862). No statistically significant differences were detected in the secondary outcomes ASES Pain, ASES Function, DASH scores, SF-12 PCS or MCS, or VAS Pain. A small difference was detected in VAS Function (median 1.3 for DI repair versus 0.5 for SI repair, p=0.023). In a multivariate linear regression model controlling for arm dominance, age, and follow-up time, SI repair was associated with a greater mean supination torque than DI repair by 19.6% at the 60°supinated position (p=0.011).
Contrary to our hypothesis, we found approximately a 20% mean improvement in terminal supination torque for acute distal biceps ruptures repaired with the single-incision technique compared to the double-incision technique. Patients uniformly did well with either technique, though we contend that this finding may have clinical significance for the more discerning, high-demand patient.
