How does an MRI measure trochlear dysplasia?
- the ratio between medial versus lateral trochlear facet length calculated as (medial facet) / (lateral facet) is one way to calculate it 8
- a ratio of <40%, in this case, indicates trochlear dysplasia.
How is MRI trochlear depth measured?
To calculate trochlear depth the distance from the trochlear groove from the before mentioned tangent is subtracted from the average of the two distances between the medial and lateral facet and that tangent 2.
What is mild trochlear dysplasia?
When the trochlea is flat, or even possibly has a convex or dome shape, it is known as trochlear dysplasia which usually is referred to as an unstable kneecap. In these circumstances, the trochlea is not shaped normally, and the patella does not have the normal bony constraints to provide stability.
How is patellar tilt measured?
Patellar tilt can also be assessed using the patellofemoral angle (PFA). PFA is the angle between a line drawn along the bony lateral patellar facet and another line along the anterior aspect of the femoral condyles. It is measured at the mid-point of the patella on the axial slices [48].
What is Type C Trochlear dysplasia?
Type C is characterized by a crossing sign and a double contour sign (asymmetry of trochlear facets with a hypoplastic medial condyle) on the lateral view. Type D is characterized by crossing sign, supratrochlear spur and double contour sign (asymmetry of trochlear facets plus vertical join and cliff pattern).
Does Trochlear dysplasia require surgery?
Dr. Welch recommends non-surgical management for most patients with trochlear dysplasia. A dedicated physical therapy program is a very important part of the treatment plan. Physical therapy focuses on strengthening of the core muscles, hip muscles, as well as the quadriceps to help stabilize the patella.
What is normal Trochlear depth?
A distance between the tibial tubercle and the trochlear groove of less than 15 mm is considered normal. Distances between 15 and 20 mm are borderline, and distances of more than 20 mm indicate marked lateralization of the tuberosity.
What is the normal TT TG distance?
Several studies suggest that a normal TT-TG distance is 10 mm or less [5, 7, 8]. A TT-TG distance greater than 15 mm in patients with patellofemoral insta- bility may predict limited benefit from phys- ical therapy [7].
What is normal patellar tilt angle?
Normal patellar tilt: Normal patellar tilt: ∠AB < 20° Page 12. Patellar Congruence Angle: Merchant Method.
What is the trochlea knee?
The trochlea is a groove in the femur bone underneath the kneecap (patella). The walls of the trochlea stabilize the patella and allow it to glide down the center of the trochlea as the knee bends.
