[Primary stability of cementless implanted hip stems made of titanium alloy with metaphyseal fixation. A prospective clinical Roentgen-Stereometry-Analysis (RSA) study].
OBJECTIVE
Under early mobilisation and full weightbearing the primary stability of two different cementless hip stems should be examined by using Roentgen Stereometric Analysis (RSA).


METHODS
26 patients (slashed circle 60.8+/-7.5 J., 16 m, 10 w, BMI 27.7+/-3.9 kg/m2) received a total hip arthroplasty with an anatomical designed image-stem (IS) (Smith & Nephew, Schenefeld, Germany), 20 patients (slashed circle 60.0+/-10.9 J., 12 m, 8 w, BMI 27.5+/-3 .7 kg/m2) the Bicontact-stem (BS) (Aesculap, Tuttllingen, Germany). RSA measurements were done before mobilizing, 3 and 6 weeks, 3, 6, 12 and 24 months postoperatively. Furthermore the patients had to estimate their pain on a visually scale (VAS). We registrated the Harris-Hip-Score (HHS) and the Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC).


RESULTS
Both stems showed the maximum of subsidence in the first 3 months (IS 0.647 mm, BS 0.54 mm). 6 months postoperative the measured migrations were in the range of the accuracy. After 2 years the subsidence was 1.07 mm+/-0.07 mm for the IS-group, 0.97 mm+/-0.18 mm for the BS-group. There were no significant differences in the examined parameters between the both groups. An excellent prostheses function and high activity grade with a high WOMAC score, a high HHS and a low VAS was founded for both groups.


CONCLUSIONS
Both cementless implanted titanium hip stems showed a sufficient primary and midterm stability with excellent clinical results. The measured migrations do not differ from those given in literature for cemented stems.
Steimer
O
O
Klinik für Orthopädie und Orthopädische Chirurgie, Universitätsklinikum des Saarlandes, Germany. olisteimer@yahoo.de
Adam
F
F
Johann
S
S
Pape
D
D
D000368:Aged; D000497:Alloys; D001843:Bone Cements; D020099:Coated Materials, Biocompatible; D017886:Durapatite; D019544:Equipment Failure Analysis; D005260:Female; D005271:Femur Head Necrosis / Q000000981:diagnostic imaging / Q000601:surgery*; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000601:surgery*; D010147:Pain Measurement; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011474:Prosthesis Design; D011859:Radiography; D014025:Titanium
D000497:Alloys; D001843:Bone Cements; D020099:Coated Materials, Biocompatible; C031462:titanium alloy (TiAl6V4); D017886:Durapatite; D014025:Titanium