TABLE III.
The H:A Ratio for THA with DM Articulations in Each Available Head and Shell Combination*
| Head Diameter (mm) | Acetabular Shell Diameter (mm) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 46 | 48 | 50 | 52 | 54 | 56 | 58 | 60 | 62 | 64 | 70 | 72 | |
| 22 | 0.48 | 0.46 | 0.44 | |||||||||
| 28 | 0.61 | 0.58 | 0.56 | 0.54 | 0.52 | 0.50 | 0.48 | 0.47 | 0.45 | 0.44 | 0.40 | 0.39 |
*
DM constructs use either a 22.2-mm or 28-mm head. Therefore, nearly all DM constructs will have an H:A ratio of <0.60. Italicized numbers represent a ratio between 0.50 and 0.59. The only exception involves a 46-mm acetabular component (boldfaced number).