Midshaft clavicle fracture following osteosynthesis with a hook plate: a retrospective case analysis.

Purpose: The clavicle hook plate has been commonly used to treat distal clavicle fractures and acromioclavicular (AC) joint dislocations; however, midshaft clavicle fracture at the medial end of the hook plate remains an underestimated complication. We aimed to discover the risk factors for this complication and the influence of these risk factors on patients and to suggest preventive surgical techniques.
Methods: We retrospectively reviewed the records of 150 patients with acute distal clavicle fractures or acute AC joint dislocations treated by internal fixation with a clavicle hook plate. The patient demographics, the occurrence of midshaft clavicle fracture at the medial end of the hook plate, and functional outcomes were analyzed. The functional outcomes were evaluated with the American Shoulder and Elbow Surgeons (ASES) Shoulder Score and grading of the Constant shoulder score after the hook plate was removed.
Results: In total, 17 patients had complicating midshaft clavicle fractures at the medial end of the hook plate. Elderly patients had a higher risk of developing this complication than young patients. The odds ratio was 4.4 (p < 0.05). The average ASES score and grading of Constant score of these patients were 74.1 and 16.3 points, respectively, which were significantly inferior to those of patients without complications (p < 0.001).
Conclusion: The incidence of midshaft clavicle fractures following osteosynthesis with a clavicle hook plate was not negligible, especially in elderly patients. This complication may impair shoulder function and quality of life. Awareness of this complication and the risk factors for this complication reminds us to perform such operations with caution.