Coracoclavicular Ligament Reconstruction: Coracoid Tunnel Diameter Correlates With Failure Risk

Abstract

The current study compared tunnel diameter as an independent risk factor for fixation failure from the coracoid after transcoracoid coracoclavicular reconstruction. The effect of variation in coracoid size and scapular bone density on fixation failure was also studied. Sixty-two cadaveric scapulae were randomized into 1 of 4 groups: a control group with no coracoid hole, a group with a 4-mm transcoracoid tunnel, a group with a 6-mm transcoracoid tunnel, and a group with a socket technique using a 6-mm hole superiorly with a 4-mm hole inferiorly. Bone density measures for all specimens were performed. Coracoid dimensions were quantified. Using a cortical button device, all specimens were loaded to failure with an Instron servohydraulic testing machine (Instron Corp, Canton, Massachusetts). All drilled specimens failed by button pullout, and all control specimens failed by coracoid fracture. Average pullout strength for each tunnel subgroup was as follows: 4 mm, 296.9 N; 6 mm, 146.2 N; 6-4 socket, 261.8 N; control, 762.9 N. No difference was found with respect to tunnel subgroups in base height (P=.25) or bone density (P=.44). Load to failure for the control group was significantly higher than for the other 3 techniques. The 4-mm tunnel load to failure was significantly higher than that for the 6-mm tunnel (P=.006). No difference was found between the 4-mm tunnel and the 6-4 socket technique (P=.853). Although it was not statistically significant, a very strong trend was seen toward increased strength of the 6-4 socket over the 6-mm tunnel (P=.051). The study results show that when employing a transcoracoid reconstruction technique, a 4-mm tunnel technique is significantly stronger than a 6-mm tunnel technique. None of the coracoids drilled with the various tunnels approached the strength of the native coracoid controls using a looped wire technique.

Two-Year Outcomes After Primary Anatomic Coracoclavicular Ligament Reconstruction

“…Recently, several studies independently showed a significantly increased risk of fracture when large bone tunnels were created in the distal clavicle or coracoid to allow for graft passage. [51][52][53][54][55] Specifically, clavicular bone tunnels of 5 mm or greater in diameter and coracoid bone tunnels of 4 mm or greater in diameter were associated with bony failure. As a result, many surgeons have begun to prepare the distal clavicle and coracoid using bone tunnels with smaller diameters to decrease the risk of fractures.…”

The frequency of reduction loss after arthroscopic fixation of acute acromioclavicular dislocations using a double-button device, and its effect on clinical and radiological results

“…We believe that appropriate visualization of the inferior surface of coracoid process and drilling with a 4-mm drill close to the base of the coracoid is essential. In a cadaveric study, Rylander et al [21] showed that a 4-mm tunnel technique is significantly stronger than a 6-mm tunnel technique when using a transcoracoid reconstruction technique. In addition, tunnel placement is also a significant factor to avoid coracoid fractures and failure of fixation.…”

The frequency of reduction loss after arthroscopic fixation of acute acromioclavicular dislocations using a double-button device, and its effect on clinical and radiological results

“…We believe that appropriate visualization of the inferior surface of coracoid process and drilling with a 4mm drill close to the base of the coracoid is essential. In a cadaveric study, Rylander et al [21] showed that a 4-mm tunnel technique is significantly stronger than a 6-mm tunnel technique when using a transcoracoid reconstruction technique. In addition, tunnel placement is also a significant factor to avoid coracoid fractures and failure of fixation.…”