Kneecap (Patellar) Instability
Patellar Instability Treatment in St. Louis, Missouri
Your kneecap serves an important purpose: protecting the knee – which is not only the largest joint in the body but also especially prone to injury due to its complexity and the amount of weight-bearing stress it must endure. Also called a patella, the kneecap’s normal position is at the front and center of the knee, where it fits into a V-shaped groove (trochlea) at the bottom of your thighbone (femur). The kneecap moves up and down when the leg is bent or straightened.
If your kneecap slips partially out of place – something called kneecap instability or patellar subluxation – it can result in pain, limited mobility, arthritis, and fracture. You may have heard it being referred to as a floating kneecap or trick knee. When the kneecap slips completely out of place, it is called a patellar dislocation.
How Kneecap Instability Occurs
The kneecap may be displaced or dislocated from its groove due to a direct blow to the knee or a severe twist of the leg. It most often occurs as the result of a sports injury. It sometimes occurs if the groove in the femur is structurally insufficient to hold the kneecap in place (e.g., too shallow or irregularly shaped).
Symptoms of kneecap displacement or dislocation include a popping or cracking in the knee, pain that worsens after activity, stiffness and swelling, and a buckling or locking of the kneecap. You might notice the kneecap slide left or right. A medial dislocation means the kneecap slides toward your inner leg. A lateral dislocation is the opposite, with the kneecap moving toward the outer leg.
There are a variety of injuries and problems that can result with an unstable kneecap, including:
- Jumper’s knee (also called patellar tendonitis or Sinding-Larsen-Johansson disease)
- Patellofemoral pain syndrome
- Patellar tracking disorder (subluxation when the leg is bent or straightened)
- Runner’s knee (also called chondromalacia)
Oftentimes, when the kneecap slips out of alignment, muscles and ligaments in the area are damaged, as well.
Treating an Unstable Kneecap
Most often, conservative, nonsurgical treatment methods can be used to alleviate your symptoms such as the use of an immobilizing brace or cast followed by physical therapy.
If surgery for patellar instability is necessary, it may include:
The medial patellofemoral ligament (MPFL) keeps the kneecap secure by pulling it toward the inner leg. If the MPFL is damaged, you may notice your kneecap slide in the opposite (lateral) direction, toward the outer leg. If that is the case, your orthopedic surgeon may recommend an MPFL reconstruction, which involves using a donor tendon to reconstruct the damaged MPFL to better secure the kneecap.
In this procedure, a small piece of the bony ridge at the top of your shinbone – called the tibial tuberosity – is transferred to the tendon that helps your kneecap glide up or down with leg movement. If this particular tendon is the cause of your kneecap instability, a tibial tuberosity transfer can help keep your kneecap secure within its groove.
Once you suffer a joint dislocation, you are more susceptible to future displacements or dislocations. While future occurrences may be accompanied by less pain each time, recurrences actually cause greater injury to your knee.
Knee Pain Treatment in St. Louis, MO
If your knee feels weak or unstable, make sure you see the orthopedic expert who can restore your mobility with the least-invasive means available. Call Dr. Jason Browdy, an orthopedic surgeon specializing in disorders of the knee, shoulder, and elbow in St. Louis, Missouri at (314) 991-2150 or request an appointment now.