luxating patella

Patellar luxation occurs when the patella is pushed out of this groove, usually laterally, causing pain, swelling, and temporary deformity in the knee joint. The patella usually moves spontaneously when the patient moves the leg, but if this does not happen, it must be moved by a qualified medical professional.

What is patellar luxation?

Patellar (kneecap) dislocations are common and can be very uncomfortable for patients. The patella sits in a groove (cart) in the femur where it normally slides up and down during movement. When the patella is forced out of this groove, a dislocation occurs, usually laterally, causing pain, swelling, and temporary deformity in the knee joint. The patella often moves spontaneously when the patient moves the leg, but if this does not happen, it should be moved by a qualified medical professional.

Perhaps more common is patellar subluxation, which is a partial dislocation that is repositioned before the point of total dislocation. There is still pain and swelling due to bone-to-bone friction, and in a subluxation or dislocation, the patient may feel scared and unsteady.

What causes patellar luxation?

There are a number of precipitating factors that can cause patellar luxation. Shape of the trochlea, size and shape of the patella, intrinsic muscular or ligamentous joint laxity, stage of maturation, muscular imbalance and poor proprioception.

Patella luxation occurs more often in younger athletes, possibly due to some of the factors mentioned above and possibly due to active activity. Misalignment occurs either extrinsically (direct contact with an external force) or intrinsically (from internally generated forces), typically during a twisting landing or twisting during sports such as gymnastics, rugby, or soccer.

What are the signs and symptoms?

Patellar luxation is evident that does not move spontaneously. The patella is on one side of the knee, usually on the outside, and the patient is initially unable to move the knee. Pain and swelling soon follow. Patients will feel the knee "give" upon impact or landing, and fear will limit movement. Often, patellar dislocations cause other injuries, such as patellar ligament damage, bone-to-bone friction, which can cause bone fragments to dislodge, tears in the joint capsule, and other soft tissue injuries.

A subluxated patella has similar symptoms to a dislocation, except that the patella is repositioned before dislocating completely. So the symptoms are pretty much the same except for the dislocated deformity.

What else?

There are other conditions that can mimic subluxation, such as meniscus tears, jumping knees, patellofemoral pain syndrome, bone injuries, and many others. However, the deformity of the luxating patella is very pronounced.

What can be done about it?

In case of a dislocated patella, it is important to go to the emergency room so that the patella can be repositioned safely, while checking for other injuries, such as bone damage. Dislocations often hide the fact that other injuries have occurred.

If the patella spontaneously dislodges, it is still recommended that the knee be checked out in the ER for similar reasons as above. Many times, however, patients are not fully aware of what is happening and often go home to care for an increasingly swollen knee.

For most injuries it is important to control inflammation to start the rehabilitation process as quickly as possible, so a PRICE (protection, rest, ice, compression, elevation) regimen should be followed. Be careful when applying ice as leaving it on too long can make the swelling worse! Also, always place a barrier between the ice and the patient's skin, and try to use melted ice (not straight from the freezer) to avoid ice burns.

Once the patient feels well, static quadriceps exercises should be performed as soon as possible, as this will help eliminate swelling and begin to restore muscle function. Movement and strength will gradually return over time.

Since the severity of this condition varies widely, it is difficult to provide a time frame for these processes.

For the fastest recovery and to minimize the chance of reinjury, it is recommended that you seek the services of a licensed sports therapist or physical therapist who has extensive training in sports injury management.

Author's Opinion

Patella luxations can be very traumatic, as they can render an athlete almost completely debilitated over a period of time. The pain and swelling take time to go away, but perhaps the most debilitating aspect is the fear that it will happen again. Careful rehabilitation through gradual recovery activities is essential not only to repair the injury, but also, ultimately, from a psychological point of view, to bring the athlete back to the level of competition. A postgraduate sports therapist or physiotherapist with the appropriate sport-specific qualifications will be able to assist with this rehabilitation process.