Saw tooth patello--femoral arthritis

Four patients with an unusual form of patello-femoral arthritis are described. The characteristic feature of the condition is an erosive 'saw tooth' pattern characteristically seen on both sides of the joint. Radiologically, this pattern is best seen on the skyline view. The other principal features are a lamellar-like pattern on slightly oblique lateral views, a smooth supra patellar erosion of the femur seen on the lateral view and cortical ridging of the lateral femoral condyle seen 'en face' on the AP projection. A possible mechanism to account for the radiological features is proposed. Anbarasu, A., Loughran, C. F. (2000). Clinical Radiology55, 767-769.