Between September 1980 and May 1982, 112 primary unilateral total hip arthr
oplasties with the original cemented M. E. Muller Straight stem (manufactur
ed from Protasul-10, a CoCrNiMo alloy) were inserted in 109 consecutive pat
ients, all combined with non-cemented, noncoated polyethylene RM cups. Fort
y-three patients (40%) died during the follow-up period, all with the impla
nt in place. Of these surviving patients, 2 (1.8%) were lost to follow-up,
and 7 (6.3%) were unable to attend the 15-year clinical and radiological fo
llow-up. Eight stems (7.3%) had to be revised for aseptic loosening and 3 s
tems (2.7%), for septic loosening. The 15-year survivorship of the Muller S
traight stem regarding aseptic loosening is, therefore, 92.7%. Forty-six pa
tients with 49 total hip replacements could be evaluated clinically and rad
iologically after 15 years. The mean duration of clinical follow-up for the
se 46 patients (42.2%) was 14.8 years (range 12.8-16.5 years). There were 2
2 women (48%) and 24 men (52%). The mean age at the time of the operation w
as 62 years (range 38-80 years), and 78 years (range 59-93 years) at the ti
me of the latest follow-up. The mean Harris Hip Score at the latest follow-
up evaluation of the 49 hip joints was 85 points (range 34-100 points). Of
the 46 patients, 39 (85%) had a good or excellent clinical result. Radiogra
phic follow-up was performed for 49 hips 35 (70%) had linear or focal osteo
lysis in one or more zones of the stem, but only 4 (8%) had evidence of def
initive loosening (linear radiolucency of over 2 mm all around the stem). S
ubsidence of over 2 mm was found in 20 hips (41%), 6 of them within the cem
ent mantle. There was no correlation between subsidence and pain. The cause
for the poor results is primarily the high rate of aseptic loosening of th
e non-coated, non-cemented all-polyethylene RM cups, with a loosening rate
of 63% and a revision rate of 25% after 15 years.