End cap versus no end cap in intramedullary nailing for displaced midshaft clavicle fractures: influence on implant-related irritation

Purpose: Implant-related irritation at the entry site is a known disadvantage of intramedullary nailing for clavicle fractures. The purpose of this study was to compare implant-related irritation rates of intramedullary nailing with or without an end cap for displaced midshaft clavicle fractures. Methods: Two cohorts of patients treated with intramedullary nailing with or without an end cap were matched and compared. Primary outcome was patient-reported implant-related irritation. Secondary outcome parameters were complications. Results: A total of 34 patients with an end cap were matched with 68 patients without an end cap. There was no difference in implant-related irritation (41 versus 53%, P = 0.26). Significantly more minor revisions were observed in the group without an end cap (15 versus 0%, P = 0.03). For complications requiring major revision surgery, significantly more implant failures were observed in the end cap group (12 versus 2%, P = 0.04). Regardless of their treatment, patients with complex fractures (AO/OTA B2–B3) reported significantly more medial irritation compared to patients with simple fractures (AO/OTA B1)(P = 0.02). Conclusion: The use of an end cap after intramedullary nailing for displaced midshaft clavicle fractures did not result in lower patient-reported irritation rates. Although less minor revisions were observed, more major revisions were reported in the end cap group. Based on the results of this study, no end caps should be used after intramedullary nailing for displaced midshaft clavicle fractures. However, careful selection of simple fractures might be effective in reducing implant-related problems after intramedullary nailing.