Medial Patellar Facet

facies articularis medialis patellae

The medial patellar facet is the smaller medial articular surface of the patella, separated from the lateral facet by the vertical patellar ridge. The most medial strip of cartilage is the odd facet, which only contacts the medial femoral condyle in extreme knee flexion (greater than 135 degrees). Medial facet cartilage degeneration is the classic pattern in lateral patellar tilt syndrome.

Region: Knee

Clinical Relevance

Clinical Notes

Medial patellar facet chondromalacia (grade I-IV) is detected by MRI and arthroscopy in patellofemoral pain syndrome. In lateral patellar tilt, the lateral facet is overloaded and the medial facet is under-loaded, producing lateral facet fibrillation and medial facet disuse changes. Medial facet bruising occurs in lateral patellar dislocation when the patella impacts the medial femoral condyle during reduction. The odd facet cartilage is at risk in patients who habitually squat in extreme flexion.

Pathology

Common Injuries & Conditions

Medial Patellar Facet Contusion in Lateral Patellar Dislocation

Lateral patellar dislocation causes the medial patellar facet to impact the anterior medial femoral condyle during spontaneous reduction, producing characteristic bone marrow oedema at the medial patellar facet and the anterolateral femoral condyle on MRI — the bone bruise pattern diagnostic of patellar dislocation.