From: Modular dual mobility articulation in primary and revision hip arthroplasty: lights and shadows
 | Head 22 | Head 28 | Head 32 | Head 36 |
---|---|---|---|---|
Data | ||||
Alfa | 45.00° | 45.00° | 45.00° | 45.00° |
Beta | 15.00° | 15.00° | 15.00° | 15.00° |
Offset | 0Â mm | 0Â mm | 0Â mm | 0Â mm |
R | 11Â mm | 14Â mm | 16Â mm | 18Â mm |
Intermediate | ||||
tan(α) | 1 | 1 | 1 | 1 |
cos(β) | 0.97 | 0.97 | 0.97 | 0.97 |
tan(Ψ) = tan(α) * cos(β) | 0.97 | 0.97 | 0.97 | 0.97 |
Ψ = arctan(Ψ) | 44.01° | 44.01° | 44.01° | 44.01° |
ϴ = arcsin (offset/R) | 0.00° | 0.00° | 0.00° | 0.00° |
Results | ||||
JD = 2R sin((π/2 − Ψ − ϴ)/2) | 8.6 mm | 10.9 mm | 12.5 mm | 14.1 mm |