Radiographic measurements of normal elbows: clinical relevance to olecranon fractures.

This study aims to calculate a clinically relevant and intra-operatively accessible measure of olecranon length that could be reliably applied by the operating surgeon to optimise fixation of comminuted olecranon fractures. One hundred normal adult antero-posterior and lateral radiographs of the elbow were studied with respect to the proximal olecranon height (OH), trochlear notch width (TW) on lateral views, and trans-epicondylar distance (TED) and trochlear width distance (TWD) on AP views. Three mean ratios were then derived: TWD/TW, TED/TW and OH/TW. The average OH was 26.2 mm (range 21-29), TW was 24.7 mm (range 21-32), TED was 58.7 mm (range 49-74), and the TWD was 27.0 mm (range 22-32). The average ratio of TWD: TW was 1.08 (SD = 0.08), that of TED: TW was 2.38 (SD = 0.18) and OH/TW was 1.06 (SD = 0.08). Comminuted fractures of the olecranon are a surgical challenge since it is often impossible to gauge the correct length to achieve in reconstruction of the olecranon process. Our data can be easily applied to the clinical situation, by taking intra-operative radiographs, and calculating the ratios as demonstrated above. These will guide the surgeon to obtain a more reliable length of the olecranon intra-operatively.