Image-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation: a cadaver study.

BACKGROUND: Reconstruction of the coracoclavicular ligament functions to restore anatomic alignment of the clavicle and may improve biomechanical function and clinical outcomes. Improper placement of the coracoclavicular tunnel may inherently weaken the coracoid. The purpose of this study was to evaluate the feasibility and accuracy of navigated image-free placement of K-wires for coracoclavicular tunnel position in comparison to conventional drill guide-based placement. MATERIALS AND METHODS: Eight human shoulder specimens were assigned for conventional technique with a coracoclavicular guide device (group CP) and the paired contralateral side for the navigated procedure (group NP) with an optoelectronic system with a fluoro-free software module. First-pass accuracy (%) and the K-wire trajectory (lateral-center orientation (LC), center-center (CC) orientation and medial-center orientation (MC) were measured. RESULTS: In all navigated K-wires a 100 % first-pass accuracy was observed. In three of the eight (37.5 %) specimens of the drill guide-based group, drilling had to be repeated. One of them had to be repeated twice, resulting in eight versus twelve drillings for the navigated versus conventional group, respectively (p = 0.021). K-wire trajectory showed an MC orientation in most of the specimen (n = 9, group NP 4, group CP 5). CONCLUSIONS: Image-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation has higher first-pass accuracy in comparison to conventional drill guide-based placement and, therefore, may enable a precise anatomic position of the drill holes and reduce the risk of an iatrogenic coracoid fracture.