Fifteen-year results of the Muller CoCrNiMo straight stem

Citation
Da. Raber et al., Fifteen-year results of the Muller CoCrNiMo straight stem, ARCH ORTHOP, 121(1-2), 2001, pp. 38-42
Citations number
27
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Ortopedics, Rehabilitation & Sport Medicine
Journal title
ARCHIVES OF ORTHOPAEDIC AND TRAUMA SURGERY
ISSN journal
0936-8051 → ACNP
Volume
121
Issue
1-2
Year of publication
2001
Pages
38 - 42
Database
ISI
SICI code
0936-8051(200101)121:1-2<38:FROTMC>2.0.ZU;2-0
Abstract
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.