Elevated Serum Titanium Level as a Marker for Failure in a Titanium Modular Fluted Tapered Stem.

Serum ion concentrations of cobalt and chromium are commonly used to monitor for the development of local metal reactions in metal-on-metal total hip arthroplasties, as well as dual-modular constructs. Although rarely used in clinical practice, elevated serum titanium levels have the ability to indicate a failure with contemporary revision constructs, such as with titanium modular fluted tapered (TMFT) stems. The authors report the case of a 64-year-old man with a TMFT stem after revision total hip arthroplasty for a dual-modular neck construct who had set screw disengagement with subsequent proximal body loosening. The patient's serum cobalt and chromium levels were normal, but he had a markedly elevated serum titanium level, indicating failure of the titanium modular junction. Implant failures at modular junctions in femoral components are well described. Although several different failure mechanisms have been defined, to the authors' knowledge this is the first reported failure of this particular TMFT stem. In addition, this is the first report describing the use of serum titanium levels in identifying a novel failure mechanism. With the popularity of this stem, surgeons should be aware that an elevated serum titanium level may aid in the diagnosis of this unique complication. [Orthopedics. 2016; 39(4):e768-e770.].