The osseo-integration of an uncemented acetabular component depends on its initial stability. This is usually provided by under-reaming of the acetabulum. We have assessed the fixation of 52mm porous-coated hemispherical prostheses inserted into cadaveric acetabula under-reamed by 1, 2, 3 and 4mm. We tested the torsional stability of fixation, after preloading with 686N in compression, by measuring the torque required to produce 1° and 2° of rotation. Under-reaming by 2mm and 3mm gave significantly better fixation than 1mm (p<0.01, p<0.02). Insertion after under-reaming of 4mm caused some fractures. To obtain maximum interference fit and optimal implant stability, we recommend the use of an implant 2mm or 3mm larger than the last reamer.
ASJC Scopus subject areas
- Orthopedics and Sports Medicine