WHAT IS THE ROLE OF THE patello-femoral ligament?
The patella is a relatively small bone, in comparison to other bones of the knee, but it is still the largest sesamoid bone of the body. Sesamoid bones are bones embedded within a tendon, and in the case of the patella, the quadriceps tendon. Normally, the patella moves during knee flexion and extension, following the trochlear groove, a channel-like groove in the anterior side of the femur, thus forming the patello-femoral joint.
The ‘‘leading role’’ of the medial patello-femoral ligament (MPFL in medical literature) as a primary stabilizer of the patella and the key element in preventing total or partial dislocation, has only recently been recognized. Patellar dislocation results in rupture of the medial patello-femoral ligament, and in chronic cases, the MPFL can be abnormally lax or ‘‘deficient’’.

WHEN IS surgical treatment for patellar dislocation NECESSARY?
For the moment, there have been few epidemiological studies to examine the mechanisms of MPFL ruptures, but it has been established that they are the result and not the cause of a patellar dislocation. In 2015, a study published by The Open Orthopaedics Journal reported an increase in the detection of this type of injury attributed to more accurate diagnostic imaging.
In cases where surgical treatment for patellar dislocation is deemed necessary–osteochondral injury with loose body formation in the joint– medial patello-femoral ligament (MPFL) reconstruction is performed. This surgical technique is rarely performed independently (there is a specialized algorithm used), and specific anatomical knowledge is crucial. The graft, used to stabilize the patella back to its normal position, is harvested from the patient and the surgery aims to repair what caused the initial patellar dislocation.

WHAT HAPPENS AFTER THE SURGERY?
Postoperatively, a brace is used to keep the knee fully extended. The primary rehabilitation period, which includes physiotherapy sessions, lasts 6 to 8 weeks, whereas return to physical activities, depending on the sport, is estimated to happen after 3 to 6 months.