Midflexion instability in revision total knee arthroplasty

Surg Technol Int. 2008;17:249-52.


Midflexion instability is a new concept associated with revision total knee arthroplasty. It appears as rotational instability with combined external rotation and valgus stress in a knee flexed between 45 degrees and 90 degrees. Three main factors contribute to this instability: anterior medial collateral ligament attenuation, femoral-tibial articular geometry, and tibial post-femoral box geometry. Rotational stress should be included when assessing stability intraoperatively to identify those patients who may require additional constraint.

Publication types

  • Review

MeSH terms

  • Arthroplasty, Replacement, Knee / adverse effects*
  • Humans
  • Joint Instability / diagnosis
  • Joint Instability / etiology*
  • Joint Instability / prevention & control*
  • Knee Prosthesis / adverse effects*
  • Reoperation / adverse effects