<unk>  To assess the knee, a clinician can perform the patellar apprehension test by moving the patella back and forth while the people flexes the knee at approximately 30 degrees. The people can do the patella tracking assessment by making a single leg squat and standing, or by lying on his or her back with knee extended from flexed position. A patella that slips laterally on early flexion is called the , and indicates imbalance between the VMO and lateral structures. On X-ray, with skyline projections, dislocations are readily diagnosed. In borderline cases of subluxation, the following measurements can be helpful: * The lateral patellofemoral angle, formed by: :*A line connecting the most anterior points of the medial and lateral facets of the trochlea. :*A tangent to the lateral facet of the patella. :With the knee in 20° flexed, this angle should normally open laterally. * The patellofemoral index is the ratio between the thickness of the medial joint space and the lateral joint space (L). With the knee 20° flexed, it should measure 1.6 or less. File:Lateral patellofemoral angle.jpg File:Lateral and medial joint space of patella.jpg
Patellar dislocation
Patellar tendon rupture
Patella fracture
Knee dislocation  Knee dislocation  1
Knee dislocation
Acetabular fracture
Hip dislocation
Humerus fracture