Radioanatomical measurements of the medullary cavity of the humerus in Kuwait: ethnic differences and clinical implications for fracture fixation.

OBJECTIVE To compare the difference in diameter of the medullary cavity of the humerus in Arab and South Asian patients in Kuwait. SUBJECTS AND METHODS In 46 patients (29 Arab, 17 South Asian) treated at Al-Razi Hospital, Kuwait, for diaphyseal fracture of the humerus, the medullary cavity of the humerus on the radiographs of the uninjured (contralateral side) was examined. Bone density was also measured. Statistical significance was calculated by parametric and nonparametric test using SPSS package. RESULTS South Asians had a significantly narrower medullary cavity (p < 0.05) and higher cortical indices (p < 0.05) than Arabs, and also a narrower external diameter of the humerus at levels 5 and 6 (p < 0.05). CONCLUSION In cases of fracture of the humerus, radiographic measurements of the diameter of the medullary cavity of the uninjured side were essential in selecting the appropriate fixation device.