Early Results of Cementless Hip Joint Arthroplasty with the Straight Zweymller Stem.

Background: Total cementless hip joint arthroplasty is a method commonly used in the treatment of advanced hip osteoarthritis. The aim of this paper is to present the early results of hip joint arthroplasty with the straight Zweymller stem.

Materials and methods: The study enrolled 117 patients (64 women and 53 men) who underwent a total of 123 hip joint arthroplasties with the straight Zweymller stem. The mean age of the patients at surgery was 60.8 years (range: 26-81 years). The mean follow-up period was 7.7 years (range: 5-12.6 years).

Results: Pre-operative Merle dAubigne-Postel scores (modified by Charnley) of the study group were poor in all patients. Mean post-operative improvement was 6.3 points. The outcomes were classified as excellent in 42 cases (34.15%), good in 56 cases (45.53%), satisfactory in 14 (11.38%) and poor in 11 cases. Poor results were always associated with implant loosening. Heterotopic ossification was noted in 8 cases (6.5%). According to the Kaplan-Meier estimator, 5-year survival probability was 91.1% for the whole implant and 95.1% for the stem alone.

Conclusions: 1. Our follow-up data (from a mean follow-up period of more than 7 years) indicate that the straight Zweymller stem affords excellent clinical and functional results in patients operated on for advanced hip osteoarthritis. 2. In patients correctly qualified for this procedure, with good surgical technique and in the absence of complications, the risk of aseptic loosening is minimal. 3. As only medium-term follow-up data are available, there may be more cases of loosening (mainly of the acetabular cup) over time, indicating a need of regular long-term follow-up.