1. Patella: Patella is the medical term for your knee cap. Your patella helps protect your knee joint and helps with bending and straightening your knee. It is covered with cartilage on the inside which helps it glide on the trochlea, which is part of the femur or leg bone. The quadriceps tendon attaches to the patella at the top, the patellar tendon attaches at the bottom and the medial patellofemoral ligament (MPFL) attaches along the inside. These connections allow you to bend and extend your knee.
2. Patellofemoral: The name for the area around your anterior or front of your knee joint. It is made up of the patella (knee cap), Femur (thigh bone), and your tibia (shin bone). This is the Joint that the patella can come out of when you have a dislocation event.
3. Trochlea/trochlear groove: The trochlea is the name for the part of your femur where the patella sits. It is located at the bottom of your femur. A normal trochlea has a groove that the patella fits into when bending your knee. Some trochlea have a shallow groove and some have no groove at all, this is called trochlear dysplasia and can lead to patella dislocations. Additionally, some trochlea have too much bone which creates a bump rather than a groove and this can also contribute to patellar dislocations.
4. Subluxation: The patella slips partially but not completely out of the trochlea. These partial dislocations can result in pain, swelling, a popping or cracking sensation and/or stiffness.
5. Dislocation: A traumatic injury in which soft tissues are damaged as the patella completely "jumps" out of the trochlea and then comes forcibly back into place. Because the patella typically dislocates toward the outside of your leg, the ligament on the inside - the medial patellofemoral ligament (MPFL) - tears or stretches.
6. Medial Patellofemoral Ligament (MPFL): The MPFL is a ligament along the inside of your patella that helps to stabilizes the patella (kneecap). When a patellar dislocation occurs, it can be torn or irreversibly stretched out. The MPFL works as a check reign to help your patella tracking within the trochlear groove during knee range of motion.
7. TT-TG – Is the abbreviation for Tibial Tuberosity to Trochlear Groove distance. This measures the offset between the part of the tibia where your patellar tendon inserts and the deepest part of your trochlea. A high TT-TG can be a risk factor for patella dislocations.
8. Patella Alta – Is the term used when your patella (knee cap) sits higher up than normally. When your patella sits higher than it should it can mean that it does not sit in the trochlea when the knee is straight and can be more susceptible to dislocating.
9. Cartilage: Cartilage is the shiny, smooth coating at the end of bones. It protects the bone and allows the bones to move smoothly and efficiently.
10. Autograft: A piece of tissue that is harvested from your own body, such as a part of your hamstring tendon, that can be repurposed into a new ligament.
11. Allograft: A piece of tissue, such as a hamstring tendon, that is harvested from a donor that can be repurposed into a new ligament.