During total knee replacement for severe varus osteoarthritis, the surgeon notes the posterior cruciate ligament (PCL) is deficient. Which implant design choice is mandated by this finding?

• A Cruciate-retaining (CR) design with a flat polyethylene insert
• B Posterior-stabilized (PS) design with a central tibial post engaging a femoral cam ✓
• C Medial pivot design relying on an asymmetric conforming surface
• D Bicompartmental replacement sparing the patellofemoral joint

Explanation

A deficient or absent PCL requires a posterior-stabilized (PS) TKR design. The PS design incorporates a central tibial polyethylene post that engages a femoral cam mechanism during flexion, substituting for PCL function in preventing posterior tibial subluxation. A cruciate-retaining implant depends on an intact PCL for rollback and stability; using CR in the absence of the PCL results in posterior tibial subluxation and failure. The other options do not address PCL deficiency.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.