Objective: An agreement has not been reached on optimal locations of bone tunnels for coracoclavicular ligament (CCL) reconstruction for acromioclavicular joint dislocation (ACD). This study aims to identify the convergence point (cP) between the coracoid process and clavicle in the Chinese population to assist surgeons in reconstructing the CCL for ACD.
Methods: From 2014 to 2020, 483 CT scans of the shoulders of 270 male and 213 female patients (247 right and 236 left shoulders) were collected and studied retrospectively. By overlapping the images of the transverse plane of the coracoid process and the clavicle, points a and b, and the midpoint ab (cP) were determined. Then, a series of parameters through point cP in the transverse and sagittal planes were measured. In the transverse plane this included the distance from point cP to the tip of the coracoid process (cP-cor),the distance between the medial and lateral margins of the coracoid process through point cP (Med-lat cor), the distance from point cP to the acromioclavicular joint (cP-ac), and the distance between the anteroposterior margin of the clavicle through point cP (Ap-clav). In the sagittal plane, this included the craniocaudal segment of the coracoid process (Cc-cor), and the craniocaudal segment of the clavicle (Cc-clav). The sex and side differences of these measurements were also analyzed by two radiologists.
Results: Based on the following measurements, point cP was determined. For male patients, the cP-cor was 28.02 ± 3.43 mm, Med-lat cor was 22.78 ± 2.80 mm, Cc-cor was 15.11 ± 2.13 mm, cP-ac was 29.24 ± 3.84 mm, Ap-clav was 18.27 ± 2.46 mm, and Cc-clav was 10.09 ± 1.56 mm. For female patients, the cP-cor was 25.20 ± 3.26 mm, Med-lat cor was 20.21 ± 2.97 mm, Cc-cor was 13.03 ± 1.77 mm, cP-ac was 26.66 ± 3.45 mm, Ap-clav was 16.10 ± 2.30 mm, and Cc-clav was 8.91 ± 1.40 mm. All the measurements of female patients were lower than those of male patients (p < 0.01). Between sides, only cP-ac of the left shoulders was significantly lower than those of the right shoulders (p < 0.05), with no significant differences in other parameters between sides (p > 0.05).
Conclusion: The results of this study identified the locations of bone tunnel-cP in the coracoid process and clavicle for the CCL reconstruction in ACD. Moreover, the findings indicated that surgeons should be more cautious in operating on female patients and that the cP-ac of left shoulders should be set lower than that of right shoulders.
Keywords: acromioclavicular joint dislocation; bone tunnel; computed tomography; coracoclavicular ligament reconstruction; overlapping images.
© 2022 The Authors. Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.