Patella Dislocation | Dislocated Kneecap

What is a patella dislocation or dislocated kneecap?

The patella (kneecap) moves smoothly up and down because moves along a track at the end of the femur (thigh bone), known as the trochlear groove.  An unnatural twist, fall, or direct hit can knock the patella out of place, partially or entirely, causing extreme pain, stiffness, and swelling. Sometimes, an underlying anatomic abnormality can cause the patella to dislocate with little to no force or effort. Most patella dislocations are lateral (outer aspect of the knee) and can damage surrounding tissue and ligaments. Patients may have patellar instability without a dislocation, where the patient feels like the patella is about to pop out of the groove – or may have done so but returned back to its place. This patellar instability without dislocation is worked up similarly and treated just as seriously. Dr. Prem N. Ramkumar, patella dislocation specialist, is located in Long Beach and serves the Los Angeles, Orange County, and surrounding Southern California areas.

How do you dislocate your kneecap?

A patella dislocation typically occurs in athletes during a rapid change of direction, causing the knee joint to twist. A direct hit to the kneecap caused by an accident or fall can also knock the patella out of place.  As previously mentioned, a patella dislocation or subluxation (incomplete dislocation) may occur with little or no force due to an underlying knee abnormality. For example, young women who are loose-jointed, patients with a higher-riding kneecap, or those with a shallow or non-existent trochlear groove tend to experience patella dislocations more often than the rest of the population.

There are two types of patella dislocations:

• Traumatic patellar dislocation: The patella is no longer in the trochlear groove in the femur.  It can happen if you fall, are in an automobile accident, or suffer a sports injury.  This type of dislocation usually damages other ligaments in the knee.

• Patella subluxation: The kneecap slides partially out of the trochlear groove.  It can happen once or repeatedly, which causes strain on the medial patellofemoral ligament, resulting in knee pain and a sense of giving way.

If you experience a dislocated kneecap, contact Dr. Ramkumar as soon as possible so he can help you achieve stability in your kneecap through either nonsurgical or surgical means. Besides pain and instability, this problem can result in cartilage damage that wears down the overall joint.

What are the symptoms of a dislocated kneecap?

Symptoms of a patella dislocation include severe knee pain, swelling and:

• Visual deformity of the knee
• Buckling, locking, or catching sensation in the knee
• A popping sound at the time of injury or dislocation
• Pain along the inside of the ligaments or under the kneecap

Remember, the pain you feel after dislocating your kneecap can go away or be intermittent.  Dr. Ramkumar advises you to seek treatment even if you no longer experience pain because cartilage damage progresses with each recurring subluxation or dislocation.

How is a patella dislocation diagnosed?

In true dislocations, the patient may be able to relocate (push the patella back into the groove) themselves or, sometimes, have this done in the emergency room. Sometimes, the kneecap will slip back into place on its own after a dislocation.  If this should happen, it is still critical to make an appointment with Dr. Ramkumar so he can make a proper diagnosis and help prevent another dislocation.

Once in the office, Dr. Ramkumar will obtain a thorough patient history and perform a physical exam.  He will inquire about the events leading up to the patella dislocation.  He will also use X-rays and most likely an MRI scan to assess the ligaments of the knee and check for any cartilage damage or loose bodies.  Loose bodies are pieces of bone or cartilage floating free in the knee due to dislocation and can cause an obstruction within the joint.  Untreated loose bodies can cause locking, buckling, or additional knee pain.

What is the best treatment for a dislocation of the patella?

If you suffer from a patella dislocation, you need early care to help stabilize your joint. If this is your first patella dislocation, Dr. Ramkumar will usually try a more conservative, non-surgical approach unless you have a loose body or injury to the cartilage. In that case, Dr. Ramkumar will recommend surgery to repair the cartilage damage and place the patella back in the trochlear groove.

Non-Surgical Treatment:

First, a patella dislocation requires immediate relocation (reduction). You will receive pain medication, and then Dr. Ramkumar will gently slide the kneecap back in place. After that procedure, you will likely benefit from a knee brace to help protect the knee, increase stabilization, and decrease swelling.  While the injury heals, you will use crutches to help you walk and begin physical therapy to strengthen the knee muscles and improve kneecap stability. NSAIDs (non-steroidal anti-inflammatory drugs) will also help reduce swelling and pain.

Surgical Treatment:

If non-surgical treatments fail to stabilize the patella, surgical reconstruction may be necessary.  The surgery Dr. Ramkumar recommends is based on your diagnosis and may include one or more of the following procedures:

• Lateral lengthening: Loosens the tether pulling the kneecap out of place, sometimes performed alongside an MPFL reconstruction but never in isolation
• MPFL Reconstruction: Reconstructs the medial patellofemoral ligament (MPFL), which attaches the femur (thigh bone) to the inside side of the patella.
• Medical Imbrication (Reefing): Tissue tightening on the inner side of the knee
• Tibial Tubercle Osteotomy: Procedure to realign the forces balancing the kneecap in relation to its groove.
• Knee Arthroscopy: Dr. Ramkumar performs this procedure if he needs to see inside the knee to determine the extent of cartilage damage, assess how the kneecap moves, and evaluate any other contributions of pain.

Recovery time depends on the procedure, but full recovery for patella dislocation surgery generally takes 6 months.  You will receive post-surgery protocols for the specific surgery you received and begin extensive physical therapy as soon as it is safe.