This in vitro study tested how femoral component design and cementation technique affect cement penetration in metal-on-metal hip resurfacing. Using 42 fresh-frozen human femoral heads controlled for bone density, the authors compared five commercial implants and then swapped cementation techniques between the highest and lowest clearance designs. The goal was to separate the effect of implant clearance from that of cement viscosity.
When a resurfacing femoral component loosens or the neck fractures, think about cement penetration, and remember that the implant you pick largely sets it before you touch the cement gun.
Radial clearance is the mental model: a tight, conical, low-clearance shell like the BHR leaves nowhere for cement to sit, so it gets driven deep into bone (66%), while a high-clearance cylindrical design forms a thick mantle and stays shallow.
This creates two opposite failure modes to avoid. Too much penetration (over 6 mm) heats bone above 50°C and causes thermal necrosis; too little (under 3 to 5 mm) gives poor interlock and loosening. The practical pitfall: do not use one implant's cementation recipe on another. Thick cement in a low-clearance BHR left 4 of 6 heads unseated, and incomplete seating predicts early neck fracture.
Follow each manufacturer's technique for that specific implant, and recognize that more cement is not better since BHR and Conserve Plus had similar mid-term survivorship despite very different penetration.
This in vitro study tested how femoral component design and cementation technique affect cement penetration in metal-on-metal hip resurfacing. Using 42 fresh-frozen human femoral heads controlled for bone density, the authors compared five commercial implants and then swapped cementation techniques between the highest and lowest clearance designs. The goal was to separate the effect of implant clearance from that of cement viscosity.
When a resurfacing femoral component loosens or the neck fractures, think about cement penetration, and remember that the implant you pick largely sets it before you touch the cement gun.
Radial clearance is the mental model: a tight, conical, low-clearance shell like the BHR leaves nowhere for cement to sit, so it gets driven deep into bone (66%), while a high-clearance cylindrical design forms a thick mantle and stays shallow.
This creates two opposite failure modes to avoid. Too much penetration (over 6 mm) heats bone above 50°C and causes thermal necrosis; too little (under 3 to 5 mm) gives poor interlock and loosening. The practical pitfall: do not use one implant's cementation recipe on another. Thick cement in a low-clearance BHR left 4 of 6 heads unseated, and incomplete seating predicts early neck fracture.
Follow each manufacturer's technique for that specific implant, and recognize that more cement is not better since BHR and Conserve Plus had similar mid-term survivorship despite very different penetration.