[Design and first clinical results with the ZMR taper revision prosthesis].
OBJECTIVE
The purpose of this study was to survey and to evaluate the first clinical and radiological results with the cementless ZMR taper hip prosthesis.


METHODS
The modular distal-tapered stem was designed with a roughened titanium surface and sharp splines to achieve secure distal fixation and rotational stability. 90 ZMR taper hip prostheses were implanted between October 1999 and July 2002. Out of these, 4 interventions were primary and 86 were revision procedures. In 43 cases a complete hip prosthesis revision and in 43 cases a stem revision was necessary. The mean age of the 90 patients (42 males, 48 females) was 67.1 years. The mean follow-up period was 7.6 months (3 to 25 months).


RESULTS
The stem displayed an excellent distal fixation. The mean subsidence could be measured with 4.3 mm. Furthermore, most cases showed a particularly favourable remodelling of the proximal femoral bone stock. Complications associated with revision included intraoperatively 4 femur fractures, 3 femur fissures, 5 femur perforations, 2 trochanter fractures and postoperatively 19 dislocations, 5 superficial wound infections, 2 transient palsies, 1 pulmonary embolism, 1 stem rotation and 4 wound healing failures. Considering these complications 15 re-revisions were necessary and the ZMR taper hip prosthesis had to be exchanged in 3 cases.


CONCLUSIONS
On the one hand the ZMR taper hip prosthesis proved its value, particularly with regard to the stem modularity, the excellent distal fixation in conjunction with the possibility of partial body weight bearing and the rapid bone remodelling of the femur. On the other hand an increased number of postoperative complications and re-revisions occurred. Further long-term studies seem to be essential.
Klinik für Orthopädie und Rheumatologie, Philipps-Universität Marburg. hinrichs@med.uni-marburg.de
F
F
Hinrichs
U
U
Boudriot
M
M
Hünerkopf
P
P
Griss
D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000706:statistics & numerical data*; D015984:Causality; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006620:Hip Fractures / Q000000981:diagnostic imaging / Q000453:epidemiology*; D006622:Hip Prosthesis / Q000145:classification / Q000706:statistics & numerical data*; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000453:epidemiology*; D008297:Male; D015995:Prevalence; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011859:Radiography; D012086:Reoperation / Q000706:statistics & numerical data; D016896:Treatment Outcome