BACKGROUND: The most common location of a displaced fracture of part of the radial head is often described as the anterior lateral aspect of the radial head with the forearm in neutral position, based on observation rather than precise measurements. The purpose of our study was to measure the exact location of fractures involving part of the radial head using quantitative 3-dimensional computed tomography (CT). MATERIALS AND METHODS: We measured the fracture lines with respect to the biceps tuberosity in 24 patients with a displaced articular fracture of part of the radial head (Mason type 2). Two observers preformed each measurement twice. Reliability was measured using the concordance correlation coefficient according to Lin. RESULTS: The average start of the fracture was 97° (standard deviation [SD]) 48.3°; range 31°-254°) clockwise from the biceps tuberosity, the average end of the fracture was 241.6° (SD, 61.0; range 19°-330°), and the average fracture subtends was 170° (SD, 32.8°; range 99°-252°). The fracture was through the anterolateral quadrant of the radial head in 22 of the 24 patients and through the posteromedial quadrant in 2 patients. CONCLUSION: This quantitative analysis of CT scans of displaced articular fractures of part of the radial head (Mason type 2) confirms that the most common location is the anterolateral quadrant with the forearm in neutral rotation. Given the important role of the radial head in elbow stability, more accurate characterization of incomplete radial head fractures may improve our understanding of treatment and outcome of these fractures.
BACKGROUND: The most common location of a displaced fracture of part of the radial head is often described as the anterior lateral aspect of the radial head with the forearm in neutral position, based on observation rather than precise measurements. The purpose of our study was to measure the exact location of fractures involving part of the radial head using quantitative 3-dimensional computed tomography (CT). MATERIALS AND METHODS: We measured the fracture lines with respect to the biceps tuberosity in 24 patients with a displaced articular fracture of part of the radial head (Mason type 2). Two observers preformed each measurement twice. Reliability was measured using the concordance correlation coefficient according to Lin. RESULTS: The average start of the fracture was 97° (standard deviation [SD]) 48.3°; range 31°-254°) clockwise from the biceps tuberosity, the average end of the fracture was 241.6° (SD, 61.0; range 19°-330°), and the average fracture subtends was 170° (SD, 32.8°; range 99°-252°). The fracture was through the anterolateral quadrant of the radial head in 22 of the 24 patients and through the posteromedial quadrant in 2 patients. CONCLUSION: This quantitative analysis of CT scans of displaced articular fractures of part of the radial head (Mason type 2) confirms that the most common location is the anterolateral quadrant with the forearm in neutral rotation. Given the important role of the radial head in elbow stability, more accurate characterization of incomplete radial head fractures may improve our understanding of treatment and outcome of these fractures.