Abstract
A secure bone cement interface between the acetabulum and the cement mantle of the hip socket is an important requirement for the long-term success of a cemented hip arthroplasty. Cement pressurisation after bone bed cleaning enables cement to penetrate interstices of cancellous bone forming a superior fixation strength.
We designed an in-vitro experiment to evaluate the performance of the Exeter, Depuy T-handle and a plunger-type pressurisers using two parameters: cement penetration and cement pressurisation.
The deformation of the flexible pressure head of the DePuy model produced a cement mantle, which is thick at the pole but tapered at its rim and variable in the amount of penetration produced (range 2–8mm) for an estimated similar force. Pressures of up to 60KPa were generated throughout the model acetabulum. The Exeter pressuriser was found to produce cement mantles more compatible with a socket. However, the test results show a wide variation in cement penetration occurring for what was estimated to be a similar applied force (3mm to 9mm at the pole and 5mm to 9mm at the rim). It was also shown to have the disadvantage of causing widely dissimilar pressures at the pole and the rim. The plunger protrusion required to produce 5mm cement penetration was found to be 7.5mm. Since this protrusion can be monitored and controlled by the operator, a cement intrusion of 5mm +/−1mm was found to be reproducible with the plunger-type device. The maximum variation in intrusion between rim and pole was 1 mm. Maximin pressures of 70KPa were generated.
We have presented experimental evidence that suggests that a plunger type of acetabular cement pressuriser may provide a more consistently reproducible level of pressurisation leading to optimal cement penetration.
Correspondence should be addressed to The Secretary, BHS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
