Clavicular anatomy and the applicability of precontoured plates.

Background: Plate fixation of clavicular fractures is technically difficult because of the complex anatomy of the bone, with an S-shaped curvature and a cephalad-to-caudad bow. The purpose of the present study was to characterize variations in clavicular anatomy and to determine the clinical applicability of an anatomic precontoured clavicular plate designed for fracture fixation.

Methods: One hundred pairs of clavicles were analyzed. The location and magnitude of the superior clavicular bow were determined with use of a digitizer and modeling software. Axial radiographs were made of each clavicle and the precontoured Acumed Locking Clavicle Plate, which is designed to be applied superiorly. With use of Adobe Photoshop technology, the plates were freely translated and rotated along each clavicle to determine the quality of fit and the location of the "best fit."

Results: The location of the maximum superior bow was lateral, with a mean distance of 37.2 +/- 18.4 mm from the acromial articulation and with a mean magnitude of 5.1 +/- 5.9 mm. There was no significant difference in the location or magnitude of the apex of the bow between specimens from male and female donors. The anatomic precontoured clavicular plate had the best fit in specimens from black male donors and the worst fit in specimens from white female donors, with a poor fit being seen in 38% (nineteen) of the fifty specimensfrom white female donors. The best location for superior plate application was along the medial aspect of the clavicle.

Conclusions: The apex of the superior bow of the clavicle is typically located along the lateral aspect of the bone, whereas the medial aspect of the superior surface of the clavicle remains relatively flat, making it an ideal plating surface. The precontoured anatomic clavicular plate appears to fit the S-shaped curvature on the superior surface of the majority of clavicles in male patients but may not be as conforming in white female patients. While this plate fits in the medial three-fifths of the clavicle, it does not fit as well laterally.