At the Orthopaedic Department of the University of Basel, a total of 540 ce
mented Muller titanium alloy (Ti6Al7Nb) Straight Stems were inserted betwee
n 1989 and 1993. A cohort of 120 consecutive patients (66 women, 54 men) wi
th 126 prostheses operated on between March and December 1989 were followed
clinically and radiologically in a prospective manner for a mean observati
on time of 9.1 years. In all cases, the Muller titanium alloy Straight Stem
was combined with the senior author's (E.W.M.) Press-Fit Cup. The mean age
of the patients at surgery was 66 (range 43-93) years. Fourty patients (41
hips) died, 9 were interviewed by telephone, none was 'lost to follow-up'.
Seventy-one patients with 76 hip replacements were available for the follo
w-up. Four hips had been revised: two of them due to aseptic loosening of t
he femoral component, one because of a late infection - all after 9 years -
and one owing to a periprosthetic fracture after 6 years. The 9-year overa
ll survivorship is 96.8%, and for aseptic loosening of the stem 98.4%. None
of the cups had to be revised for aseptic loosening. The clinical result (
according to Merle d'Aubigne) was excellent and good in 88%, moderate in 8%
, and poor in 4%. The radiological analysis showed no osteolysis or radiolu
cent lines in 59 prostheses (78%). Nine stems (12%) showed a radiolucent li
ne. Focal osteolysis was detected in 8 cases (10%) in one or more Gruen zon
es. The distribution of the osteolyses shows that predominantly zones VII,
VI, V, and II are affected in decreasing frequency. No osteolysis was detec
ted on the acetabular side. Our results do not confirm the high rate of ost
eolysis and revisions with the Muller titanium alloy Straight Stem presente
d by some other institutions. The verdict on a specific endoprosthetic impl
ant must be made by combined assessment of the design, the implant surface
condition, the material, the cement, the cementing procedure and the operat
ive technique. The statement made in earlier publications that cemented tit
anium alloy should not be used as a femoral stem prosthesis should be recon
sidered.