Abstract
Aseptic loosening is the most frequent cause of implant failure in total hip arthroplasty (THA). Additionally, failure rate was still found by some authors to be increased in patients with osteonecrosis of the femoral head (ON-FH). It is well evidenced that low initial fixation and early migration precedes and predicts long-term failure rate of both, the acetabular and femoral component in THA.
This independent, double-blind, randomized, controlled study was primarily designed to evaluate whether a single infusion of 4 mg of zoledronic acid is sufficient to prevent implant migration determined by the EBRA-digital method. Fifty patients were consecutively enrolled between July 2002 and March 2005 to receive either 4 mg zoledronic acid (ZOL) or saline solution (CTR) one day after THA (Zweymüller system, cementless). Plain radiographs were performed postoperatively and all parameters were evaluated at each follow-up meeting interval at 7 weeks, 6 months, 1 year, and yearly thereafter during a median follow-up period of 2.8 years (2 years minimum).
In CTR, subsidence increased up to −1.2 mm ± 0.6 SD at 2 years in CTR (P< 0.001). Less, but a near curve-linear shaped migration pattern was found for the ace-tabular component, with an averaged medialization of 0.6 mm ± 1.0 SD and a cranialization of 0.6 mm ± 0.8 SD at 2 years (P< 0.05, Friedman ANOVA) at 2 years. In ZOL, a significant reduction in bone turnover markers was accompanied by a complete prevention of cup migration in both, the transverse and vertical direction (P< 0.05, ANOVA), while there was only a trend to a decreased subsidence in stems.
The study provides useful data which are promising and support the suggestions that bisphosphonates may offer significant opportunities to reduce and prevent implant migration of THA, thus increasing long-term durability of THA especially in selected high-risk patients.
Correspondence should be addressed to EORS Secretariat Mag. Gerlinde M. Jahn, c/o Vienna Medical Academy, Alserstrasse 4, 1090 Vienna, Austria. Fax: +43-1-4078274. Email: eors@medacad.org
