Semitendinosus vs Gracilis Grafts With 1- vs 2-Tunnel Techniques for Coracoclavicular Ligament Reconstruction: A Biomechanical Study.

Background: Despite the evolution of acromioclavicular joint surgery to a more anatomic coracoclavicular (CC) ligament reconstruction, no definitive guidance regarding the number and position of bone tunnels in the clavicle, as well as the ideal graft choice, is established.

Purpose/hypothesis: The purpose of this study was to biomechanically compare the reconstruction of the CC ligament complex between gracilis- and semitendinosus-tendon grafts in 1- and 2-tunnel techniques. It was hypothesized that the gracilis tendon graft will provide comparable primary stability in both tunnel techniques while utilizing a smaller tunnel diameter.

Study Design: Controlled laboratory study.

Methods: A total of 24 cadaveric shoulders (13 men, 11 women; 66 ± 7.5 years) were randomly allocated to 4 repair groups: gracilis with 1 tunnel (GT-1), gracilis with 2 tunnels (GT-2), semitendinosus with 1 tunnel (ST-1), and semitendinosus with 2 tunnels (ST-2). First, specimens were tested for native anterior, posterior, and superior translations. Then, specimens were randomly assigned to 1 of the 4 CC reconstruction groups before undergoing the same testing, followed by cyclic loading and load to failure (LTF).

Results: The GT-2 reconstruction demonstrated significantly less translation when compared with ST-2 in anterior ( = .024) and posterior ( = .048) directions. GT-1 and ST-2 both showed significantly less translation than ST-1 in anterior and superior directions ( < .001). All reconstructions demonstrated less superior translation compared with native testing, with GT-1 and ST-2 significantly less than ST-1 ( < .001). There were no significant differences for peak displacement and LTF between groups.

Conclusion: Gracilis tendon grafts using a 1- or 2-tunnel technique for CC ligament reconstruction provided comparable translation, displacement, and LTF as corresponding semitendinosus grafts. Therefore, the gracilis tendon should be considered as a biomechanical equivalent graft choice for the reconstruction of the CC ligament complex.

Clinical Relevance: In a cadaveric model, the gracilis tendon demonstrated adequate fixation with minimal translation in CC ligament reconstruction while utilizing smaller diameter bone tunnels, which may help minimize the risk of complications such as loss of reduction and fracture.