Anatomic Tunnel Placement Is Not Feasible by Transclavicular-Transcoracoid Drilling Technique for Coracoclavicular Reconstruction: A Cadaveric Study

Abstract

To evaluate the feasibility of anatomic tunnel placement by a transclavicular-transcoracoid drilling technique and with reference to the coracoclavicular ligaments' insertional anatomy and their orientations. We used 12fresh-frozen human cadaveric shoulders (6 matched pairs; mean age, 70years; age range, 51-82years) to simulate intraoperative tunnel placement with the transclavicular-transcoracoid drilling technique. After both the conoid and trapezoid ligaments were identified, two 2.5-mm guide pins were inserted from the clavicle to the coracoid, passing the centers of the clavicular and coracoid insertions of the conoid and the trapezoid ligaments, in a collinear fashion to the orientation of both ligaments. The entry point of the drill at the clavicle and the exit point at the coracoid undersurface, as well as the tunnel orientations, were measured. Complications due to the procedure, including a breach of the bone cortex of the clavicle and/or coracoid process, were recorded. The transclavicular-transcoracoid drilling technique for anatomic conoid ligament tunnel placement resulted in a medial cortical breach at the coracoid process in 6 of 12shoulders. In the remaining 6 shoulders without a breach, the distance of the exit point from the medial cortex of the inferior coracoid process was only 3.6 ± 4.3mm. For anatomic trapezoid ligament tunnel placement, no medial cortex breaching at the coracoid process occurred. However, the distance of the exit point was 3.1 ± 4.2mm, indicating an eccentric location to the medial cortex of the coracoid process, similar to the conoid ligament. This cadaveric study showed that anatomic tunnel placement by the transclavicular-transcoracoid drilling technique would not be feasible without breaching or almost breaching the medial cortex of the coracoid process. The transclavicular-transcoracoid drilling technique for CC ligament reconstruction may not reproduce the anatomy of the CC ligaments but may place the coracoid process at high risk of fracture during tunnel placement.