Femoral head size: variation among manufacturers

Nine manufacturers were contacted for their specific femoral head diameters of the 22 mm, 28 mm, and 32 mm femoral components. The 22 mm heads averaged .869 in. (+/- .005) and 100% were within 1 standard deviation; however, the standard deviation was large. The 28 mm heads averaged 1.101 in. (+/- .002), and 89% were within 1 standard deviation. The 32 mm heads averaged 1.258 in. (+/- .002), and 78% were within 1 standard deviation. It seems that when a 28 mm or 32 mm femoral head is used, different femoral and acetabular components by different manufacturers can be intermixed. However, when changing a 22 mm femoral head, the manufacturer should possibly be notified and an attempt to use the same manufacturer is preferable.