Radiostereometric Analysis of Subpectoral versus Suprapectoral Biceps Tenodesis with Interference Screw Fixation

Objectives: Biceps tenodesis is performed with increasing frequency for various pathologies of the long head biceps tendon (LHBT). Multiple surgical techniques and devices for tenodesis have been described with favorable outcomes. The subpectoral approach provides adequate clinical outcomes; furthermore, recent research suggests that similar outcomes can be achieved via arthroscopic suprapectoral biceps tenodesis. Previous studies have compared the biomechanical profile of suprapectoral and subpectoral biceps tenodesis. There is a paucity of data regarding the biomechanical behavior and construct stability of suprapectoral and subpectoral biceps tenodesis in vivo. The purpose of this investigation is to quantify and compare the behavior of the biceps tenodesis construct in arthroscopic suprapectoral (ASPBT) and open subpectoral (OSPBT) techniques, with radiostereometric analysis (RSA). Methods: This is a prospective cohort study comparing migration of the biceps tendon after suprapectoral and subpectoral biceps tenodesis with Polyetheretherketone (PEEK) interference screw fixation. Thirty consecutive patients were allocated to the subpectoral group, follow by thirty consecutive patients to the suprapectoral group. Patients aged 18-65 years with symptomatic biceps tendinopathy, anterior intertubercular groove tenderness, and positive biceps tension tests were included in the investigation. Patients undergoing revision biceps tenodesis, shoulder arthroplasty, or ruptured LHBT were excluded. A mini skin staple, functioning as a radiostereometric marker, was placed longitudinally within the tendon prior to final fixation with interference screw. Staple stability was confirmed with a hemostat to gravity. The distance from the most proximal portion of the mini skin staple and the most proximal aspect of the humeral head was measured. Following final fixation with an interference screw, AP radiographs were obtained intraoperatively. Follow-up radiographs were one week and 12 weeks post-operatively. A paired and non-paired students t-test were utilized to assess for intra-group and inter-group changes, respectively. Results: A total of 60 consecutive patients (30 per group) were enrolled and available for follow-up imaging at 1 and 12 weeks postoperatively. The average age was 43.5±10.5 years, average BMI was 28.3±5.4, and 50% of the patients were females. Groups were similar with respect to patient demographics and concomitant procedures (P>.05). In the OSPBT group, the average distance of the radiostereometic marker to the proximal humeral head increased on by 26.0 mm (SD, 15.7) from the immediate post-operative radiograph to 3 months postoperatively (P=0.002). In the ASPBT group, the average distance also significantly increased by 24.7 mm (SD, 14.9) from the immediate post-operative radiograph to 3-months postoperatively (P=0.001). The change in distal migration between the ASPBT and OSPBT was not found to be statistically significant (P> 0.05). Conclusion: Biceps tenodesis performed with a PEEK tenodesis screw results in significant distal migration of the biceps tendon by 3 months post-operatively; however, there was no significant difference in distal migration between the OSPBT and ASPBT groups.