In the January 2015 issue of Orthopedic Clinics (Volume 46, Issue 1), in the article “Patellar Instability” by Jason L. Koh and Cory Stewart, an error was made regarding the various patella height ratios. Figure 1 explains methods of measuring the patellar height ratios, wherein all three methods (Insall-Salvati, Caton-Deschamps, Blackburne-Peel) are mentioned as ratios between the articular surface of the patella and its distance with tibia, i.e., patella:tendon. In the original descriptions by the aforementioned authors, the ratios are calculated as indices of tendon:patella.

The authors apologize for this error.