A comparative clinical outcome evaluation of smooth (10-13 year results) versus rough surface finish (5-8 year results) in an otherwise identically designed cemented titanium alloy stem.
BACKGROUND
We retrospectively compared the influence of surface finish with respect to the long-term durability of a cemented titanium alloy stem of the same design but different surface finish.


METHODS
From 1984 to 1994, the stem was made of a titanium-aluminum-vanadium alloy. A total of 201 patients with 220 smooth stems (mean follow-up 11 years and 4 months) out of 612 implanted between 1984 and 1987 and 319 patients with 343 rough stems (mean follow-up 5 years and 10 months) out of 812 implanted between 1991 and 1993 could be reviewed clinically and radiologically for comparison. The average age of the patients with the smooth stem was 58.1 years and of the patients with the rough stem, 62.2 years. In both groups, 35% of patients were male and 65% female.


RESULTS
The mean Merle d'Aubigné hip score increased from 10.5 to 16.0 points in the smooth stem group and from 11.0 to 16.9 points in the rough stem group. The distribution of radiolucent lines, according to the zones of Gruen, was similar in both groups. The smooth stem required revision in 18 cases after a mean follow-up of 11 years and 4 months and the rough stem in 30 cases after a mean follow-up of 5 years and 10 months. The survival analysis (Kaplan-Meier) revealed 95.4% survival after 13 years for the smooth femoral component and 76.7% survival after 8 years for the rough femoral component.


CONCLUSIONS
The implantation of titanium alloy stems with a rough surface finish cannot be recommended because of its high aseptic loosening rate.
Department of Orthopedic Surgery, Philipps University of Marburg, Germany. hinrichs@med.uni-marburg.de
F
F
Hinrichs
M
M
Kuhl
U
U
Boudriot
P
P
Griss
D000497:Alloys; D019644:Arthroplasty, Replacement, Hip; D001843:Bone Cements; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012189:Retrospective Studies; D013499:Surface Properties; D014025:Titanium; D016896:Treatment Outcome
D000497:Alloys; D001843:Bone Cements; C031462:titanium alloy (TiAl6V4); D014025:Titanium