Cementless total hip replacement: a prospective clinical study of the early functional and radiological outcomes of three different hip stems.
BACKGROUND
Optimal fixation of cementless total hip stems is essential for long-term survival rates.


OBJECTIVE
The purpose of this prospective study was to evaluate the early clinical and radiological outcomes of two new total hip stems with metaphyseal (Symax®) and predominantly diaphyseal (Hipstar®) anchoring principles in comparison to the well-established straight Zweymueller (SL-Plus®) stem.


METHODS
Clinical and radiological evaluations of 74 patients were undertaken preoperatively as well as at 6 and 12 months postoperatively using the Harris Hip Score (HHS) and Western Ontario and McMaster Universities-Score.


RESULTS
During follow-up no stem had to be revised. The mean preoperative HHS of the three study groups amounted to 54.6 ± 15.7 points. At the 12 months follow-up the mean HHS in the SL-Plus group (n = 22) was 88.3 ± 10.5 points, in the Hipstar group (n = 25) 83.3 ± 15.0 and the in Symax group (n = 27) 83.6 ± 15.1. Due to stress shielding the straight Hipstar stem revealed radiolucent lines in the proximal Gruen zones of about 60%, whereas the SL-Plus stem showed significantly more radiolucent lines (87%). However, subsequent long-term studies must be carried out in order to clarify if the progression of radiolucent lines may influence the clinical result and implant longevity.
Bergschmidt
Philipp
P
Department of Orthopaedics, University of Rostock, Doberaner Strasse 142, 18057 Rostock, Germany. philipp.bergschmidt@med.uni-rostock.de
Bader
Rainer
R
Finze
Susanne
S
Gankovych
Alexander
A
Kundt
Guenther
G
Mittelmeier
Wolfram
W
D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D016009:Chi-Square Distribution; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D020127:Recovery of Function; D018709:Statistics, Nonparametric; D016896:Treatment Outcome