Arthroscopic suprapectoral and open subpectoral biceps tenodesis: a comparison of restoration of length-tension and mechanical strength between techniques.

Purpose: This study aimed to (1) evaluate the ex vivo restoration of the long head biceps length-tension for both arthroscopic suprapectoral biceps tenodesis (ASPBT) and open subpectoral biceps tenodesis (OSPBT) techniques and (2) assess how location in the proximal humerus affects pullout strength for tenodesis using an interference screw implant.

Methods: Eighteen matched cadaveric shoulders were randomized to OSPBT or ASPBT groups (9 each). Tenodesis was performed using clinical techniques. Preoperatively, a metallic bead was placed in the biceps tendon and a fluoroscopic image was obtained. Postoperatively, an image was obtained to evaluate the location of the tenodesis and the metallic bead and determine tensioning. Biomechanical load-to-failure testing was then performed.

Results: The ASPBT technique resulted in an average of 2.15 ± 0.62 cm of biceps overtensioning compared with 0.78 ± 0.35 cm (P < .001) in the OSPBT group. The average load to failure in the ASPBT group was 138.8 ± 29.1 N compared with 197 ± 38.6 N (P = .002) in the OSPBT group. Failure caused by implant pullout was significantly more frequent in the ASPBT group (7 of 9) than in the OSPBT group (1 of 9).

Conclusions: The described ASPBT technique using an interference screw implant has the tendency to overtension the biceps and has a significantly decreased ultimate load to failure compared with an open subpectoral technique in matched cadaveric specimens.

Clinical Relevance: This study shows differences in the biomechanical properties of OSPBT and ASPBT. Modification of currently published ASPBT techniques may be necessary to improve restoration of the physiological length-tension relationship of the biceps. Clinical studies may need to clarify if the lower ultimate load to failure for the ASPBT technique is clinically significant.