**Conflict of interest**

AJS has received research support from ISO-biologics, is a paid consultant for Mitek, is a board or committee member of the American Academy of Orthopedic Surgery and the New Jersey Orthopedic Society, and has stock or stock options in Biomet, CONMED Linvatec, Johnson & Johnson, Pfizer, Smith & Nephew, and Stryker. The remaining authors declare no conflict of interest.

*Patellofemoral Instability DOI: http://dx.doi.org/10.5772/intechopen.99562*
