Abstract
Background: A totally new double-threaded cone-shaped modular femoral stem has been designed, using rotational rather than percussive hammer insertion of the prosthesis. The vertical height, the neck length, the neck anteversion angle and the medial offset can all be adjusted after preparation of the femoral canal has been completed.
Methods: The new stem design and the technique of insertion are described. A consecutive series of the first 110 hip joints in 103 patients were followed clinically and radiographically for an average of 28 months.
Results: The Harris hip score average rose from 43.6 points preoperatively to 91 points postoperatively. The pain score average changed from 7.9 points to 42 points, respectively. Thirteen hips (11.8%) had mid-thigh pain, most of them mild. One hip (0.9%) showed clinical and radiographic signs of early loosening and was revised.
Conclusions: The short-term clinical and radiographic outcomes were encouraging. The double-threaded cone-shaped stem locking mechanism was shown to be able to withstand the torsional and vertical forces applied to a hip-replacement prosthesis.
The abstracts were prepared by Professor A. J. Thurston. Correspondence should be addressed to him at the Department of Surgery, Wellington School of Medicine, PO Box 7343, Wellington South, New Zealand
