Interface gap after implantation of a cemented femoral stem in pigs.
We studied the interface gap around cemented femoral stems. Fresh pig femora were used. Bone cement mixed under vacuum or at atmospheric pressure was injected into the femoral canal and a cobalt chrome stem was then implanted. The femora were sectioned transversely from the minor trochanter and distally by using a high-pressure water cutter. Most of the interfaces had intimate contact. However, in all specimens, small gaps were found at the bone-cement and cement-stem interfaces. The gaps at the interfaces between the bone and cement and the cement and stem were measured, using a computerized video digital system. They occupied about 10% of the circumference at the bone-cement interface and about 15% of the circumference at the cement-stem interface, irrespective of the mixing procedures. Most gaps were less than 100 mu at the interfaces. In conclusion, cemented implants in the animal model showed that small gaps are found at the interfaces directly after implantation. These gaps may be weak points and initiate debonding when loading the prostheses.
Wang
J S
JS
Department of Orthopedics, Lund University Hospital, Sweden. Jian-Sheng.Wang@ort.lu.se
Franzén
H
H
Lidgren
L
L
D000818:Animals; D001274:Atmospheric Pressure; D001843:Bone Cements / Q000737:chemistry / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004339:Drug Compounding / Q000379:methods*; D004353:Drug Evaluation, Preclinical; D006622:Hip Prosthesis; D006801:Humans; D007231:Infant, Newborn; D018715:Microscopy, Video; D016348:Osseointegration; D019904:Polymethyl Methacrylate / Q000737:chemistry / Q000627:therapeutic use*; D016062:Porosity; D011475:Prosthesis Failure; D011897:Random Allocation; D016037:Single-Blind Method; D013552:Swine; D014618:Vacuum
D001843:Bone Cements; D019904:Polymethyl Methacrylate