Recurrent dissociation of the tibial insert after mini-subvastus posterior-stabilized total knee arthroplasty: a case report.

We report here on an unusual case of recurrent dissociation of a polyethylene tibial insert from its metal baseplate after high-flex posterior-stabilized (PS) Genesis II total knee arthroplasty with using the mini-subvastus approach. After the 1st episode of dissociation, which had happened 1 month after the primary surgery, we changed the tibial insert and found damages on the dovetails and the post of the retrieved insert. Unfortunately, the patient suffered the same dissociation 1 month after the tibial insert was changed. This case illustrates that incomplete seating of the insert due to limited surgical exposure and anterior impingement of the high-flex PS post may contribute to the risk of dissociation.