Biomechanics of a novel technique for suprapectoral intraosseous biceps tenodesis.

BACKGROUND

The Caspari-Weber (C.W.) tenodesis is a standard miniopen intraosseous technique to fix the long head of the biceps tendon. The suprapectoral intraosseous biceps tenodesis (SPIBiT) is a novel arthroscopic, intraosseous, tendon-sparing alternative using a cortical button. No biomechanical data exist comparing the time-zero performance of the SPIBiT and C.W. constructs.

METHODS

Nine pairs of human cadaver shoulders were tested. The SPIBiT used a finger-trap suture pattern holding the tendon inside a humeral tunnel above the pectoralis tendon, anchored with a cortical button on the anterior humerus distal to the bicipital groove. The subpectoral C.W. used a Krackow suture technique. Specimens underwent 500 cycles of uniaxial loading, followed by ultimate failure testing.

RESULTS

The SPIBiT was placed in 5 left and 4 right humeri (5 female, 4 male; 59 ± 6 years). The C.W. was initially stiffer (P = .003), whereas the SPIBiT exhibited higher energy dissipation (hysteresis; P = .006). Metrics decreased for both constructs over 500 cycles (P ≤ .050). Constructs failed through suture bunching and tendon tearing within the main suture bundle. The SPIBiT exhibited a novel failure in 2 specimens, with the cortical button pulling distally and suture cutting through cortical bone. Failure occurred at 272.0 ± 114.3 N and 282.3 ± 59.4 N for the SPIBiT and C.W., respectively (P = .766). The C.W. was stiffer (P < .001).

CONCLUSION

The SPIBiT is an arthroscopic suprapectoral intraosseous alternative to the C.W. biceps tenodesis, but in light of the novel failure mode, clinical use is not recommended. Future investigations should quantify the impact of construct compliance on healing, and future constructs should avoid suture point loading on thin cortical bone.