Spontaneous late dissociation of the tibial insert after high-flex posterior-stabilized Genesis II total knee arthroplasty.

We report a rare complication of spontaneous late dissociation of the tibial insert 2 years after total knee arthroplasty using a high-flex posterior-stabilized Genesis II prosthesis (Smith & Nephew, Memphis, Tenn). It appears that 2 factors may have contributed to dissociation, namely, incomplete seating of the insert and the design of the prosthesis, which involves a shallow anterior tab snap-fit locking mechanism and thin dovetail lips.