Excessive lateral pressure syndrome
Excessive lateral pressure syndrome (ELPS) is abnormal lateral tilt of the patella without lateral translation and considered one of the relatively common causes of anterior knee pain. It can affect both adolescents or adults. Patients usually present with insidious onset anterior knee pain aggravated by physical activity.
ELPS is due to imbalance between medial and lateral dynamic stabilizers, either secondary to more common abnormally tight lateral retinaculum/vastus lateralis or lax medial retinaculum/vastus medialis. This results in lateral tilt of the patella without obvious sublaxation or dislocation. In fact, in some cases even slight medial translation can be present. Over time, chronic impaction of the lateral patellar facet to the lateral femoral trochlea ensues chondral damage and osteoarthritis.
Abnormal tilt can be measured by patellofemoral angle with medial opening of the angle or an angle less than 8° is diagnostic of ELPS in an appropriate clinical setting.
- 1. Chhabra A, Subhawong TK, Carrino JA. A systematised MRI approach to evaluating the patellofemoral joint. Skeletal Radiol. 2011;40 (4): 375-87. doi:10.1007/s00256-010-0909-1 - Free text at pubmed - Pubmed citation
- 2.FACR TPMD, Bloem HL, FACR JBMD et-al. Musculoskeletal Imaging. Saunders. (2014) ISBN:1455708135. Read it at Google Books - Find it at Amazon
- 3. Koskinen SK, Taimela S, Nelimarkka O et-al. Magnetic resonance imaging of patellofemoral relationships. Skeletal Radiol. 1994;22 (6): 403-10. Pubmed citation