What is Patellar/Patellofemoral Instability:
The patella, or kneecap, is a small bone that sits in a groove at the front of the knee. It is held in place by the surrounding ligaments and muscles to stabilize and protect the knee joint. Patellofemoral instability results when the patella shifts, slides partially out of place (subluxation), or pops out of the groove completely (dislocation). This is a relatively common knee condition with the highest prevalence among adolescent females, though anyone can be affected.
Causes
Several factors can increase the likelihood of patellofemoral instability, including excessive applied force, muscle weakness, loose ligaments, anatomical differences, and a history of previous dislocation. Examples include twisting motions, sudden changes in direction, and direct impacts during activities such as soccer, football, and running. If the kneecap dislocates during an injury, it may slide out of place quickly and painfully, leading to significant pain and difficulty walking. Dislocation can also occur intermittently without a clear cause. Regardless of the underlying reason, it is important to be evaluated by a physician.
Symptoms
People with patellofemoral instability commonly feel pain at the front of the knee along with a sensation that the kneecap is slipping, buckling, or “giving way.” Your knee and leg may not be able to support your weight, leading to difficulty walking and standing upright.
Additional symptoms may include stiffness, swelling, and popping sounds in your knee. Repeated patellofemoral instability can lead to arthritis later in life.
Diagnosis
The diagnosis of patellofemoral instability is made by reviewing your symptoms and medical history and performing a physical examination of the knee. Common imaging tests such as X-ray and MRI can help rule out fractures, assess cartilage and ligament damage, and evaluate anatomical causes/risk factors.
Treatment
Treatment for patellofemoral instability includes both non-surgical and surgical methods, depending on the severity of the injury and whether the kneecap is likely to dislocate again. The overall treatment goal is to prevent future dislocations.
For first-time dislocations or mild instability, conservative treatment focuses on rest, wearing a supportive brace, and physical therapy to strengthen the muscles around the knee. Most people regain normal daily activity within a few weeks to months.
For repeated or more severe instability, surgery may be necessary to repair ligaments or adjust the kneecap’s alignment. These procedures are often done arthroscopically with small incisions and a camera, followed by rehabilitation to restore strength, motion, and stability. Full recovery back to sports is between 5-6 months based on severity. Following treatment plans carefully helps prevent future dislocations and supports long-term knee health.