Biomechanical comparison of acromioclavicular joint reconstructions using coracoclavicular tendon grafts with and...

The purpose of this study was to compare the initial strength of acromioclavicular joint reconstructions using coracoclavicular (CC) tendon grafts with and without coracoacromial (CA) ligament transfers.

Two different acromioclavicular joint reconstructions were performed in 7 matched pairs of cadaveric shoulders. Paired shoulders were repaired with either a hamstring allograft CC reconstruction (group 1) or a hamstring allograft CC reconstruction plus a CA ligament transfer (group 2). Intact specimens and then reconstructions were cycled from 0 to 100 N at 1 Hz for 100 cycles in a superior direction, and displacements were recorded. Finally, the stiffness of the reconstructions and the ultimate load to failure were recorded.

Superior displacement of the reconstructions after cyclic loading was 4.43 ± 1.82 mm in group 1 and 3.75 ± 1.56 mm in group 2 (P = .38). Ultimate load after load to failure was 970.3 ± 361.03 N in group 1 and 952.7 ± 296.89 N in group 2 (P = .94). Finally, stiffness of the reconstructions was 50.6 ± 6.14 N/mm in group 1 and 65.6 ± 18.45 N/mm in group 2 (P = .12).

The addition of a transfer of the CA ligament to an acromioclavicular joint reconstruction with a CC hamstring graft does not appear to significantly improve its overall initial biomechanical strength.

These data suggest that a CA ligament transfer may add very little to a CC tendon graft reconstruction augmented with high-strength suture with regard to initial, time zero displacement and strength.