Bipartite Patella

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Description of Bipartite Patella

A bipartite patella forms when a portion of the patella does not completely heal along the bony edges of the patella. Most commonly, this is in the upper and outer (superolateral) portion of the patella. Bipartite patella is quite common, usually asymptomatic, and is found in 2% of the population on x-rays. In the vast majority of people, a bipartite patella does not cause symptoms. Most often, it is found on an x-ray because a patient is experiencing symptoms that are being caused from another underlying condition.

In a small percentage of people, the bipartite patella can cause symptoms.

Symptoms of Bipartite Patella:

  • Localized pain over the superolateral patella
  • Pain with deep squats or high level of ice skating or skiing
  • Percussion of the patella over the bipartite portion almost always reproduces a patient’s symptoms

Most commonly, a bipartite patella is found after an injury. In most cases, the usual fibrous connection between the two portions of the bipartite patella is disrupted and it does not heal back normally. Dr. LaPrade sees this in athletes who play ice hockey, and in athletes who may sustain contact to their knees (such as soccer and football players).

Are you experiencing bipartite patella symptoms?

There are two ways to initiate a consultation with Dr. LaPrade:

You can provide current X-rays and/or MRIs for a clinical case review with Dr. LaPrade.

You can schedule an office consultation with Dr. LaPrade.

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(Please keep reading below for more information on this condition.)

Treatment for Bipartite Patella

The usual treatment for symptomatic bipartite patella is to try to avoid activities that cause irritation and allowing it time to quiet down. This could include avoiding contact, avoiding deep squats, lunges, and other activities that significantly stress the patellofemoral joint. In patients for whom this does not work, and who may have some other associated knee pain for which it is difficult to determine if the exact location of pain is coming from the bipartite patella, an injection into the fibrous union between the normal patella and the bipartite patella may help to differentiate if this is the source of pain. In most athletes, one can percuss on the bipartite patella area and it can duplicate their symptoms.

In patients who have limitations in function and who have undergone an appropriate period of time without any improvement of their symptoms, an arthroscopic excision of the bipartite patella has been found to be very effective. Usually, this requires 3-4 small incisions around the knee to take off this portion of the patella, shell it out arthroscopically with a bur, and to try to save the normal ligament structure on the lateral aspect of the patellofemoral joint. While one can excise them more quickly through an open incision, the open incision commonly can create a gap between the patella and the lateral retinaculum, which requires limitations of activities for a longer period of time.


With an arthroscopic procedure, one can start early range of motion, weightbearing, and a slow progression of activities to increase their function.

Dr. LaPrade has found that arthroscopic excision of a bipartite patella to be very effective at relieving pain and improving function. When the athlete follows the rehabilitation precisely postoperatively, the results can be excellent after surgery. It takes most tissues of the body about 6 weeks to heal, so activities should be limited for a minimum of 6 weeks to make sure that one does not stress the area where the bipartite patella was shelled out and give it the best chance to heal in. If one follows this protocol, there is an excellent chance of a full return to function after an arthroscopic excision of a bipartite patella.

Bipartite Patella FAQ

How common is bipartite patella?

Bipartite patella is often found as an incidental finding on patient’s x-rays.  It is present in about 2% of the population. About 50% of the time, it can be involved in both knees. In general, it is felt that bipartite patella is present in 1/50 people, with most people not knowing that they have a bipartite patella.

What to do for a bipartite patella?

Most patients who have a bipartite patella have it as an incidental finding, so usually no treatment is necessary. For those patients who do have symptoms, a program of rehabilitation and activity modification may allow the symptomatic bipartite patella to calm down.

How to read a bipartite patella MRI?

Most bipartite patellas will be asymptomatic. Thus, on an MRI scan, there should not be any increased signal between the bipartite patella and the main bony portion of the patella. For those patients who are symptomatic, the fibrous union between the bipartite patella and the main portion of the patella (kneecap) will have increased signal. In addition, often the bipartite fragment will tilt down towards the trochlea, rather than having a normal, smooth surface. These are the patients who usually have the most symptoms with a symptomatic bipartite patella.

When to have bipartite patella surgery?

Most cases of bipartite patella do not cause any significant problems. If one does have an acute onset after a blow to the knee, a trial of rehabilitation and activity modification may prove useful to allow it to quiet down. In those patients who have a very symptomatic bipartite patella, which does cause them to limit their activities, an MRI scan can be useful to determine if there is increased signal between the bipartite patella fragment and the main portion of the patella. In addition, if the bipartite patella is tilted towards the trochlea, these patients often will need bipartite patella surgery.

Usually the bipartite patella itself is relatively small and not an essential portion of the kneecap. Thus, a surgical excision would be indicated in those patients who have a lot of symptoms and have a portion of the patella that is relatively small and not contributing significantly to the patella function. In these cases, an arthroscopic excision may be indicated. We prefer an arthroscopic excision over an open excision because patients can resume activities much sooner, and there is no disruption of the lateral retinacular attachment to the patella. Recovery from an open excision of a bipartite patella can be longer, and if the lateral retinaculum fails, the patients may develop symptomatic medial patellar instability symptoms.

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