Individual anatomical risk factors for patellar instability

Over the last two decades the management of patellofemoral instability has changed with the advent of the ability to define the variation in the anatomy of the patellofemoral joint and to put a number onto that variation. From this we are able to agree what is “normal” and what is pathological. The review by Dietrich et al. (1) looks at the key method for doing this, namely imaging. The problem with the patellofemoral joint is that there is little consensus internationally on terminology, details of the history, the relevant examination techniques (which to do, how to do them, and how to report them) (2), but there is consensus on which are the important anatomical abnormalities, how to image and what to measure (1,3). As a consequence there is a better understanding about the surgical interventions needed to correct the abnormalities, although not necessarily which patients require an operation and the timing of it (4).