This UK National Joint Registry study of 337,647 primary THAs uses multivariable survival analysis to identify which cementless femoral stem design features are independently associated with revision for periprosthetic fracture within 90 days, then validates the highest-impact finding — the calcar collar — using paired cadaveric torsional biomechanical testing.
When selecting a cementless femoral stem — especially for patients at elevated fracture risk (female, osteoporotic, posterior approach) — favor a collared stem with a grit-blasted surface finish and avoid triple-tapered geometry; the collar's protective effect is backed by both the largest registry analysis to date and direct biomechanical validation showing higher torsional fracture resistance.
This UK National Joint Registry study of 337,647 primary THAs uses multivariable survival analysis to identify which cementless femoral stem design features are independently associated with revision for periprosthetic fracture within 90 days, then validates the highest-impact finding — the calcar collar — using paired cadaveric torsional biomechanical testing.
When selecting a cementless femoral stem — especially for patients at elevated fracture risk (female, osteoporotic, posterior approach) — favor a collared stem with a grit-blasted surface finish and avoid triple-tapered geometry; the collar's protective effect is backed by both the largest registry analysis to date and direct biomechanical validation showing higher torsional fracture resistance.