Outcomes and function of conoid ligament on the basis of postoperative radiographic findings of arthroscopic stabilization for the distal clavicle fractures.

PURPOSE: Distal clavicle fractures are divided into three types according to Neer's classification. These fractures are usually treated with a sling to immobilize the upper extremity, however, the treatment of type 2 fractures remain controversial. We focused on the anatomical basis of these fractures in which disruptions in the conoid ligament led to the distraction between the two bony fragments. In this study, we report an arthroscopic procedure for conoid ligament reconstruction and its therapeutic outcomes, and discuss the function of the reconstructed conoid ligament.

HYPOTHESIS: Arthroscopic conoid ligament reconstruction alone is sufficient to retain the posteriorly displaced proximal fragment of the clavicle in its reduced position.

MATERIALS AND METHODS: A retrospective cohort study were conducted on 18 patients with type 2 distal clavicle fractures. Arthroscopic techniques were performed with the patients in the beach chair position. Dacron artificial ligament® was used to reconstruct the conoid ligament, and the internal bone fixation materials included an EndoButton® on the coracoid process side and a screw with a spiked washer on the clavicle side. Preoperative assessment was performed via plain radiography or three-dimensional computed tomography to evaluate the displacement of the proximal fragment. Although the displacement was superoposterior in all the cases, the acromioclavicular joint was maintained. The mean duration of postoperative follow-up was 2 years and 5 months.

RESULT: There were no injury-related complications during the surgery and bony union was achieved within 3 months after surgery. Evaluation using 3DCT also showed that the preoperative superoposterior displacement of the proximal fragment of the clavicle was immediately reduced postoperatively, and this reduced position was maintained until the final follow-up examination.

CONCLUSIONS: We achieved good results by indirectly reducing fractures of the distal clavicle with conoid ligament damage using the minimally invasive surgical technique of arthroscopic conoid ligament reconstruction. Anatomical reconstruction of the conoid ligament might stabilize not only the superior displacement of the displaced proximal fragment of the clavicle but also its posterior displacement.

STUDY DESIGN: Case series with no comparison study.

LEVEL OF EVIDENCE: 4, retrospective cohort study.