Double-Hump Camel Sign: A Pathognomonic Manifestation of Pseudarthrosis of Patella

Abstract

Pseudarthrosis is a rare complication of patella fracture. An orthopedic surgeon may have less than 10 cases in life career. When two patellar fragments are in status of gap displacement, the pseudarthrosis can be recognized by Double-hump Camel Sign. Patient’s knee is observed from lateral view. The gap between two fragments constitutes an image of double-hump camel. During knee flexion the gap becomes bigger, while knee extension the gap smaller. Figure 1. Double-hump Camel Sign is pathognomonic for the pseudarthrosis of patella.