A 75-year-old woman with a well-functioning cemented total knee replacement 12 years ago presents with anterior knee pain only on descending stairs. Radiograph shows anterior femoral notching and stress fracture of the anterior femoral cortex. This complication is related to:

• A Excessive tibial slope causing anterior subluxation
• B Patellar maltracking due to improper component rotation
• C Undersizing of the femoral component with anterior notching ✓
• D Polyethylene insert wear causing metal-on-metal contact

Explanation

Anterior femoral notching during TKR occurs when the anterior femoral cut is made too deep, creating a stress riser in the distal femur anterior cortex. This notch weakens the bone and can lead to supracondylar stress fractures, classically presenting as anterior knee pain worsened by stair descent. It is more common with posterior-stabilized implants that require removal of more anterior bone. Proper sizing and templating with the femoral component footprint prevents this complication.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.