[Secondary stability of cemented and non-cemented acetabular implants ex-vivo under dynamic load].
OBJECTIVE
To measure the bone-prosthetic implant interface micromovement during the application of physiological load by using a material testing system (MTS).


METHODS
The cadaveric hip specimens were used to simulate a single leg stance and the joint in the neutral position. Micromovement was recorded via a 3-dimensional transducer in the acetabula of postmortem specimens, which had been preserved in formalin. The study data of the cemented and uncemented prosthsis refereed to the lone-term clinical process and the radiological status and experimental results.


RESULTS
Cemented cups showed higher transverse relative motion up to 90 microm, whereas the maximum transverse movement of the non-cemented cup was 60 microm. Orthogonal motion perpendicular to the implant surface showed compression for all cups at all sites.


CONCLUSIONS
The results indicate that there are large differences in survival time between 2 groups. That could not be compared statistically in secondary stability. Nevertheless, according to the results, the amount of micromotion of press-fit cup is relatively less than that of cemented polyethylene cup, which is instrumental in bone ingrowth and secondary stability.
Wu
Jie
J
Department of Orthopaedics, Beijing Friendship Hospital, Beijing 100050, China.
Widmer
K-H
KH
Zurfluh
B
B
Goepfert
Beat
B
Morscher
Erxin W
EW
D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001696:Biomechanical Phenomena; D001705:Bioprosthesis; D001843:Bone Cements; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D011475:Prosthesis Failure; D016474:Weight-Bearing
D001843:Bone Cements