Patellar instability, with repeated lateral dislocation, commonly seen in younger, active adults, is associated with a number of anatomical pathologies and usually requires surgical intervention. Among these, increased tibial tubercle to trochlear groove (TT-TG) distance is a prominent risk factor. TT-TG distance describes the degree of lateralization of the tibial tubercle. “TT-TG distance is routinely measured in most patients who present with a partial or complete knee-cap dislocation. This makes it an accessible piece of information that could potentially be used to identify patients at-risk for repeated dislocations,” explains Paul Sherbondy, M.D., Bone and Joint Institute.