Osseous anatomy of the distal humerus and proximal ulna: implications for total elbow arthroplasty

Abstract

Cortical thickness and multiple intramedullary canal diameters were measured in sequential axial sections from 27 human cadavers. No age or side differences were identified. The intramedullary humeral canal shape changed along the length of the bone in both male specimens and female specimens. Anteroposterior and male minimal humeral canal diameters increased proximally from the elbow. Male and female medial-lateral humeral diameters decreased proximally from the elbow. All ulnar canal diameters decreased distally in a uniform fashion. The minimal ulnar and humeral canal diameters did not occur in either the sagittal or coronal plane. Humeral and ulnar cortical thickness did not vary within axial sections. Only ulnar cortical thickness changed between sections, decreasing distally. On the basis of these data, a cylindrical humeral stem and an ulnar stem tapering in all planes may be optimal for total elbow arthroplasty stems. The relatively thin cortices of both the humerus and the ulna predispose patients to perforation, periarticular fracture, and complications during revision arthroplasty surgery. Finally, routine frontal and lateral radiographs may overestimate minimal canal size for total elbow arthroplasty components. However, the lateral view appears to approximate the true minimal canal diameter more closely.