During total knee arthroplasty, a surgeon measures the tibial component in neutral mechanical alignment. Post-op the patient develops persistent mediolateral instability. On review, the tibial tray appears to be excessively internally rotated relative to the tibial tubercle. The reference landmark used to set tibial component rotation in TKR is:
- A Tibial axis of Akagi (line from PCL center to medial border of tibial tubercle) ✓
- B Medial third of the tibial tubercle
- C Center of the PCL footprint
- D Lateral edge of the tibial plateau
Correct answer: A. Tibial axis of Akagi (line from PCL center to medial border of tibial tubercle)
Explanation
Tibial component rotation in TKR is standardly set using the Akagi line, which connects the center of the posterior cruciate ligament (PCL) footprint to the medial border of the tibial tubercle; this represents the anatomical neutral rotational axis. Malrotation of the tibial component (internal or external) is a leading cause of patellofemoral maltracking, instability, and anterior knee pain after TKR. The medial third of the tibial tubercle is used as a secondary landmark.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.