BACKGROUND: An ipsilateral fracture of the midshaft clavicle with dislocation of the acromioclavicular joint (ACJ) is a rare combination injury and almost always occurs following high-energy trauma. Currently, there is no optimal surgical approach for this kind of rare injury. We present a 60-year-old man with a traumatic combined linear midshaft clavicle fracture and ACJ injury simultaneously treated with Knowles pin fixation.

CASE REPORT: A 60-year-old male patient presented a linear midshaft clavicle fracture in the emergency room (ER) due to a road traffic accident. A linear fracture progressed to a displaced fracture at followup in the outpatient orthopedic department 3 days later. After open reduction with Knowles pin fixation for displaced clavicle fracture, postoperative followup radiographs revealed unexpected ipsilateral type V ACJ dislocation according to Rockwood classification. The next day, a closed reduction with percutaneous Knowles pin fixation was performed for ACJ dislocation. At the 1-year followup, radiographic and clinical results demonstrated complete union of the clavicle fracture and anatomic reduction of the ACJ with painless and full range of motion.

CONCLUSIONS: This report highlights that even a linear midshaft clavicle fracture can be combined with ipsilateral ACJ dislocation if the traumatic injury was caused by a high-energy road traffic accident. Therefore, an intraoperative stress view of the injured shoulder is recommended to recheck the stability of the ACJ after the clavicle fracture fixation to prevent a missed ACJ injury. In our case, an excellent outcome was achieved by using Knowles pin fixation simultaneously to treat the dual shoulder injury.

Keywords: Acromioclavicular Joint, Clavicle, Cost Savings, Fracture Fixation, Internal