Early catastrophic failure of rotating hinge total knee prosthesis.

The mechanical failure of a prosthesis component is usually observed as a late complication of total knee arthroplasty (TKA). In knees with severe ligament instability and bone deficiency, either a true hinge prosthesis or a rotating hinge implant is commonly used. Failure of the polyethylene bearing bush in a hinge-type prosthesis is a complication that has not been reported to date. We report the cases of 2 rotating hinge TKA prostheses that dislocated as a result of mechanical failure of the prosthetic component within 5 months of initial implantation. Clinicians should be aware of this potential complication when selecting rotating hinge prostheses for certain patients.