Treatment of unstable distal clavicle fractures with Knowles pin

Background: Unstable distal clavicle fractures often need surgical treatment. This report describes a new intramedullary extra-articular Knowles pin fixation method to treat these unstable fractures. Materials and methods: Twelve patients with unstable distal clavicle fractures (Neer type II) had surgery with intramedullary extra-articular Knowles pin fixation. We retrospectively reviewed clinical results for pain, shoulder function, and range of motion, as well as radiographic results, for this institutional review board-approved study. Each patient's operated arm was in a sling for 4 weeks postoperatively. The University of California, Los Angeles shoulder rating scale score was used to evaluate shoulder function. Results: All patients showed radiographically confirmed bony union. The mean period required for healing was 11.5 weeks, and patients were followed up for 6 to 24 months (mean, 15.2 months), during which University of California, Los Angeles scores (mean, 33.9) indicated good clinical results. Three patients had the complication of proximal or distal skin irritation caused by the thread and hub of the Knowles pin. Conclusions: The Knowles pin fixation method is useful for treating unstable distal clavicle fractures. However, sufficient familiarity with the technique and careful preoperative planning to determine the appropriate length of the pin are necessary to prevent complications and to effect a high union rate.