Radiostereometric Evaluation of Tendon Elongation After Distal Biceps Repair

BACKGROUND: Operative repair of distal biceps tendon ruptures has shown successful outcomes. However, little is known about the amount of tendon or repair site lengthening after repair. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate distal biceps tendon repair via intratendinous radiostereometric analysis to analyze tendon lengthening at different time intervals of healing. The hypothesis was that there is significant lengthening after repair. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Eleven patients with distal biceps ruptures requiring operative repair were recruited. During repair, two 2-mm tantalum beads with laser-etched holes were sutured to the distal biceps tendon. Beads were evaluated via computed tomography scans immediately postoperatively and at 16 weeks. Radiographs were obtained at time 0 and then at 4, 8, and 16 weeks postoperatively. Measurements were made using the button-to-bead and bead-to-bead distances to assess repair site elongation as well as tendon elongation over time. After final follow-up, patients filled out the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and underwent ultrasound to confirm the integrity of the tendon. RESULTS: Ten patients had complete ruptures, with 1 having a partial rupture that underwent completion of the tear and subsequent repair. All patients showed statistically significant lengthening after surgery. The mean amount of tendon lengthening after surgery was 22.8 mm (range, 11.2-30.9 mm; P < .05), and the repair site lengthened a mean 17.0 mm (range, 9.6-30.6 mm; P < .05) from surgery to final follow-up. The greatest change in lengthening was noted between time 0 and week 4 (mean, 11.3 mm; P < .05), with the least amount of lengthening between weeks 8 and 16 (mean, 2.6 mm; P < .05). The mean DASH score was 11.2. Final ultrasound evaluations found all tendons to be in continuity. CONCLUSION: All patients undergoing distal biceps tendon repair have significant elongation after surgery, with the greatest amount of lengthening seen in the early postoperative period.