Abstract
We have long suspected that patients treated at our institution have narrower femoral canals than the literature suggests. This has implications when it comes to nail size and the question of using reamed or unreamed nails. Using CT analysis, we studied the morphology of the femoral isthmus.
We prospectively evaluated 30 men with a mean age of 26 years (20 to 35). Patients with previous femoral fractures were excluded from the study. A scanogram determined the level of the isthmus and axial cuts at this level accurately revealed canal size and shape.
We found a canal size of less than 12 mm in 62%. In a third of these, canal size was less than 11 mm. Axial cuts showed three types of femoral canals: 14 patients had thick femoral cortices and a narrow canal, seven had thin cortices and a wider canal, and nine had an oval canal, with the larger diameter in the sagittal plane.
If one adheres to the principle of reaming until cortical clutter is heard, the recommended 12-mm or 13-mm reamed femoral nail is not suitable for the majority of non-Caucasian men in our population. Larger nails may cause such complications as delayed union, nonunion and fracture. Smaller nails of 10-mm and 11-mm diameter result in satisfactory clinical and radiological outcomes.
The abstracts were prepared by Professor M. B. E. Sweet. Correspondence should be addressed to him at The Department of Orthopaedic Surgery, Medical School, University of Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193 South Africa
