Dissociation of a Morse-Taper Stemmed Tibial Component Following Revision Total Knee Arthroplasty

Modular orthopaedic implants involving conical press-fit fixation (a Morse taper) include a tapered shank that fits into a socket of the corresponding taper, providing accurate alignment and frictional fixation. Under normal loading, the cold weld achieved between the two surfaces is stable, and dissociation between the two metal surfaces can be achieved only with excessive force 1. Consequently, failure of such components is rare. Previous studies have demonstrated that contamination by fluids, galvanic corrosion, and trauma are associated with failure of the taper lock 2-4. We report a case in which a Morse taper failed during revision total knee arthroplasty, at the time of impaction of the tibial component into the tibia. The patient was notified that data concerning the case would be submitted for publication.