Epidemiology of Patellar Instability :  Most commonly occurs in 2nd-3rd decades of life Risk factors include Ligamentous laxity (Ehlers-Danlos syndrome) Dysplastic vastus medialis oblique (VMO) muscle Lateral displacement of patella Patella alta causes patella to not articulate with sulcus, losing its constraint effects Trochlear dysplasia Excessive lateral patellar tilt (measured in extension) Lateral femoral condyle Read More →