Patella dislocation is a common problem seen in young athletic persons. Non-operative treatment is usually adviced for the first episode of dislocation. Adequate rest followed by muscle strengthening help in recover of this problem.
This dislocation of the patella from its groove (trochlear groove) can occur due to a blow to the inner aspect of the knee joint or due to violent contraction of the thigh muscle which can pull the patella out of it normal position in the trochlear groove.
If the patella has dislocated more than once, we have to investigate for the reason for such occurrence. There is a support for the patella on the inner aspect of the knee called Medial Patellofemoral Ligament (MPFL), which prevents the outward movement of the patella.
What is a Medial Patellofemoral Injury?
The medial patellofemoral ligament is a broad structure located on the inside of the knee joint. It connects the kneecap (patella) to the thigh bone (femur). The primary purpose of the MPFL is to provide stability to the kneecap; it provides restraint to any movement toward the outside of the knee. It also helps keep the kneecap in position, as the knee bends and straightens.
How Does it Feel?
Common signs and symptoms that may occur with an MPFL injury include:
- Feeling the knee “giving way” or “buckling” during activity.
- Feeling like the kneecap is sliding out to the side during knee movement.
- Swelling of the knee following activity.
- Restricted joint movement (range of motion).
- Pain when moving the joint.
- Tenderness to touch along the affected joint.
- Pain, stiffness, or “locking,” after sitting with the knee bent or straight for a prolonged period of time
How Is It Diagnosed?
When you first go to see your physician he will review your medical history, and perform a comprehensive physical exam of your knee, assessing different measures, such as range of motion, strength, and flexibility. You knee will be manipulated, placing it in certain positions to try to pinpoint which specific structures may be injured. If an MPFL injury is suspected, the mobility of the knee cap is assessed, specifically to note if it moves more to the outside compared to your uninjured knee. Additionally, you may be asked to briefly perform or describe the activities that cause your pain.
Imaging techniques, such as x-rays or an MRI, may be required to gain a more thorough and objective evaluation of all of the structures of the knee joint.