Abstract
Aims: The effects of bone graft washing and bone graft particle size on initial cup stability in an acetabular model were studied. Methods: From fresh human femoral heads large (8–12 mm) and small (2–4) grafts were produced. Four different groups were tested; large washed, large unwashed, small washed and small unwashed. An AAOS type 3 combined defect was reconstructed in a synthetic acetabular model using a metal mesh and screws. Bone grafts were impacted in a standardized way using a hammer and metal impactors. Cement was pressurized and a PE cup was inserted. Cups were dynamically loaded with 1500 N and 3000 N for 15 minutes using an MTS-device, RSA was used to calculate 3-D cup migrations. Next a lever-out test of the cup was done in a displacement (16¡/minute) controlled test. After testing CT scans of the cups were made to quantify cement layer roughness, as a measurement of cement penetration. Results: Cups reconstructed with large washed bone grafts migrated signiþcantly less during mechanical compression and withstood signiþcantly higher lever-out moments. Washing improved cup stability for both small and large grafts, however only signiþcantly for the larger bone grafts. A signiþcantly higher cement penetration depth was found for all large bone grafts, washing did not inßuence cement penetration depth. Discussion: For acetabular revisions with bone impaction grafting we recommend to use large washed bone grafts.
Theses abstracts were prepared by Professor Dr. Frantz Langlais. Correspondence should be addressed to him at EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
