The desired end result of treatment following recurrent patella dislocations is pain-free, stable patella tracking and return to normal activities. In recent years, the alternatives for achieving this goal have increased with particular focus on “metrics” or objective measurements that may be used to guide an orthopedic surgeon in accurate restoration of patella stability. Objective measurements are indeed important in the assessment of the underlying reasons for patella instability, but “normalizing” them surgically often means extensive surgery.
Art, experience and judgment needed
While metrics are important, I wholeheartedly believe, based on 35 years of doing patellofemoral surgery, that art, experience and judgment should be important factors in the decision-making process once one has viewed and studied the objective measurements (metrics). For instance, a 16-year-old girl may have some excessive femoral anteversion that causes too much internal rotation at the hip with some secondary trochlear dysplasia. 
One surgeon might justify derotation of the femur and trochleoplasty as the most appropriate surgical treatment. However, another surgeon might very well say such a patient will do well with core strengthening and, if the core strengthening alone is insufficient, a medial patellofemoral ligament (MPFL) or medial quadriceps tendon-femoral ligament (MQTFL) reconstruction. Few surgeons would derotate this young person’s femur or do a trochleoplasty, except in extreme circumstances.