Special Considerations for Pediatric Patellar Instability.

Patellar instability in children and adolescents is a challenging subset to treat. Varied forms of instability, ranging from episodic dislocation to fixed dislocation, have been recognized. It is of utmost importance for the treating physician to recognize these different patterns of instability and their associated risk factors, as more complex patterns of instability would require more extensive surgical procedures. Medial patellofemoral ligament (MPFL) reconstruction, by itself, may not suffice or may not be appropriate for the more complex instability patterns. Appropriate and early treatment of such instability in children would allow for functional progression and possible remodeling of the trochlea. However, early treatment has the associated risk of growth disturbances when surgical procedures are performed around open physis or if adult-type bony procedures are performed in children. Recent knowledge about the relationship between trochlea, MPFL femoral attachment, and distal femoral physis could help to advance safe surgical care for these patients. This article reviews the pathophysiology, risk factors, and the existing classification systems for patellar instability in children and adolescents. It focuses on varied surgical techniques, which are unique to the pediatric population, and summarizes the outcomes of these surgical techniques.