Since 1984, we have used components made of titanium alloy for total
joint arthroplasty. Recently, two patients needed revision hip
arthroplasty, approximately three years after the initial procedure,
because of aseptic loosening secondary to severe osteolysis that had been
induced by metallic debris. Although implants made of titanium alloy have
many favorable qualities--most importantly, superb biocompatibility--the
alloy is more susceptible to wear by particles of acrylic cement and tends
to generate more polyethylene wear than do components made of stainless
steel or chromium-cobalt. A new process of implanting ions has reportedly
improved resistance to wear as well as fatigue properties and has enhanced
the resistance to corrosion of the implants. Although, to our knowledge,
only in vitro studies of this process have been reported to date, we
recommend avoiding the use of components made of titanium alloy in which
ions have not been implanted. We suggest considering the possibility of
osteolysis secondary to appreciable metallic debris in patients who have
aseptic loosening of titanium-alloy components that were not implanted with
ions.