title: The Zweymller cementless total hip prosthesis in patients aged 50 years and younger.
abstract: Sixty-eight young patients (74 prostheses), mean age 43 years (standard deviation 7.7) at the time of the index operation, with a Zweymller cementless total hip prosthesis were evaluated with a mean follow-up time of 75 months (sd 15.7). At follow-up, the mean Harris Hip Score was 94 (sd 8.1). Six stem prostheses had vertical sub-sidence and nine cups showed signs indicating possible loosening. The Oxford Hip Score averaged 19 points (sd 8.7). Revision surgery was performed for septic loosening (n=3 stem and cup prostheses), for aseptic loosening of the cup (n=2), and for a traumatic periprosthetic fracture (n=1 stem). Worst case survival analysis for aseptic loosening of the cup showed a probability for revision of 3% (CI95 0 7.2%) with a cumulative survival of 96% (CI95 100 90.3%) after 84 months. For the stem prostheses the probability for revision was 1% (CI95 0 4.3%) after 114 months with a cumulative survival of 99% (CI95 100 95.8%) after 72 months. Worst case cumulative survival for any reason of revision was 94.5% (CI95 99.9 89.2%) after 81 months. Promising results of the Zweymller cementless hip prosthesis for the younger patient were obtained, although longer follow-up will be necessary. (Hip International 2005; 15: 1-11).
authors.affiliation: Department of Orthopaedic Surgery, Hospital Gooi-Noord, Laren, The Netherlands.
authors.forename: T M J S
authors.initials: TM
authors.lastname: Vervest
authors.forename: P G
authors.initials: PG
authors.lastname: Anderson