The knee is the meeting place of two important bones in the leg, the femur, and the tibia. The patella (also known as the kneecap) is the moveable bone that sits in front of the knee. This bone is wrapped inside a tendon that connects the large muscles on the front of the thigh, the quadriceps muscles, to the lower leg bone.
Bipartite patella is a congenital condition that occurs when the kneecap is made of two bones instead of a single bone. Usually, the two bones would fuse together as the child grows but in bipartite patella, they remain as two separate bones. About 1% of the population has this condition. When this condition is discovered in adulthood it is often an “incidental finding” meaning that when your healthcare provider was investigating another condition around the knee, the bipartite patella is suddenly discovered.
Additionally, bipartite patella is classified into three types of severity levels depending on how the injury occurred. The following types include:
- Type 1 – The fragment is at the inferior (bottom) portion of the patella.
- Type 2 – The fragment is found on the lateral margin (outer side) of the patella.
- Type 3 – The bone fragment is found at the supero-lateral (upper-outer) portion of the patella.
Causes & Symptoms
The patella starts out as a piece of fibrous cartilage. It turns into bone or ossifies as part of the growth process. Each bone has an ossification center, therefore, this is the first area of the structure to start changing into bone. Most bones (including the patella) only have one primary ossification center.
However, in some cases, a second ossification center is also present. Normally, these two centers of bone will fuse together during late childhood or early adolescence. If they do not ossify together, then the two pieces of bone remain connected by fibrous or cartilage tissue. This connective tissue is called synchondrosis.
The most common location of the second bone is the upper-outer (supero-lateral) corner of the patella, but the problem can occur at the bottom of the patella or along the side of the kneecap. Injury or direct trauma to the synchondrosis can cause a separation of this weak union leading to inflammation. Repetitive micro-trauma can have the same effect – the cartilage has a limited ability to repair itself and increased mobility between the main bone and the second ossification center further weakens the synchondrosis, resulting in painful symptoms.
Throughout the symptoms of bipartite patella, most patients are completely asymptomatic. This means there are no obvious signs that the kneecap hasn’t fully fused and it does not cause any problems. In most cases, however, the condition can only be discovered when the knee is X-rayed or scanned following an unrelated injury.
In some cases, bipartite patella does go on to cause problems. This typically happens when the cartilage tissue between the bones, the synchondrosis, is damaged, causing irritation and inflammation. This is usually from a direct blow to the front of the knee, a fall, or repetitive overloading at the knee.
Activities that commonly cause problems with bipartite patella are those where there is repetitive knee bending, jumping, or squatting. The most common symptoms that people do experience with symptomatic bipartite patella are:
- Tenderness – This is when pressure is placed over the bony fragment.
- Knee pain – Usually, at the top of the patella on the outer side of the knee, tends to worsen with squatting activities as more force goes through the kneecap.
- Instability – The knee may feel like it is going to give way.
- Bony ridge – You may be able to feel a slight ridge on the patella.
- Large patella – The kneecap may well be larger than usual.
- Knee swelling – Swelling in the kneecap may be present.
Who gets Bipartite Patella?
Certain risk factors linked to bipartite patella include the following:
Most athletes who present with a bipartite patella often have a blow to the kneecap that causes irritation of a previously undiagnosed bipartite patella. Those athletes who continue to have symptoms may have had the condition become injured as part of their presenting injury and there may be micro-motion at this site, which contributes to having them have pain with lunging, squatting, and other types of stressful activities to the front part of the knee. Generally, certain sports activities that typically cause problems are skiing, cycling, hill walking, and basketball.
Conditions such as osteoarthritis, osteochondritis dissecans, synovial plica, iliotibial band syndrome, medial collateral bursitis, prepatellar bursitis, and infections are all potential causes of bipartite patella.
Bipartite patella can affect both childhood (congenital) and adulthood if the condition has been left undiagnosed and left untreated. Elders are also more prone to developing bipartite patella due to the wear and tear throughout the years. This can also lead to osteoarthritis in the knee.
Both men and women (and boys and girls) are equally prone to experience bipartite patella.
How Does it Affect You? How Serious is it?
A number of things can become associated with bipartite patella if the condition is left untreated. Some complications include permanent damage to the patella and an increased chance of developing osteoarthritis in the affected kneecap.
In most cases, even surgery is required to repair the patella. Therefore, there are several options for treating a bipartite patella surgically, including:
- Replacing the connective tissue that binds the bones together with a screw.
- Removing the smaller of the two bones.
- Adjusting the tissue that keeps your kneecap centered.
Most patients typically recover within weeks after surgery, however, most others recover within a few months.
Recommended Treatment & Rehabilitation
Most patients with a bipartite patella are never diagnosed because it does not cause any symptoms. However, if you have an MRI scan or X-ray done in the area for an unrelated condition, it will likely show up. At first, it may look like a broken kneecap, but on closer look, a bipartite patella doesn’t have the jagged edge and sharp angles of a broken bone.
In most cases, no treatment is needed for patients diagnosed with a bipartite patella. If there are symptoms related to inflammation of the synchondrosis of the bipartite patella, treatment may be pursued to try to calm the inflammation of the kneecap. Some of these treatments include:
- Rest – Allowing the kneecap to rest is the first step in treatment, and often the only step necessary to resolve the symptoms of this condition. Rest may also include immobilization of the knee in a slightly bent position to take the pressure off the kneecap.
- Anti-inflammatory medications – Oral medications can be used to help relieve pain and reduce inflammations. Typically, non-steroidal anti-inflammatory drugs (NSAIDs) are used to help calm the irritated kneecap. In more severe cases, a cortisone injection, also a powerful anti-inflammatory medication, can be administered to help address the problem.
- Compression knee braces – Knee braces can help limit mobility and support the kneecap. A simple patellar compression knee brace is often the most helpful type of brace for this condition.
- Ice and heat therapy – Decreasing inflammation and relieving pain is often accomplished with the application of ice packs directly to the front of the kneecap – keep the ice pack applied for 20-30 minutes every 3-4 hours for rapid short-term relief. You can also add a heat pack to increase blood circulation in the affected area.
If you have been immobilized, then you can begin a physiotherapy session with a physiotherapist once your immobilization has been removed. During physiotherapy for bipartite patellar, your physiotherapist will begin by educating you on activity modification and implementing a period of active rest so that your symptoms can improve.
Taking ‘active rest’ means decreasing your activity intensity or duration such that you are not aggravating your knee. Some activities, however, may need to be completely avoided or replaced by less stressful ones. Avoiding excessive use of the stairs, as well as resisted weight training can help reduce further kneecap pain.
Your physiotherapist may also use electrical modalities such as ultrasound or interferential current to help ease your pain or decrease any swelling that may exist.
He or she will use an additional tape or flexible brace to assist with your symptoms. The aim of this type of treatment is to help guide the kneecap through its proper range of motion while you move the knee during your rehabilitation exercises and during everyday activity.
Once your symptoms begin to subside, your physiotherapist will design a specific exercise plan in order to ensure you maintain your full knee range of motion. The following exercise examples include:
Stand straight with your feet hip-width apart. Next, lower your bottom down and backward, as if you were going to sit in a chair. Stop when your knees reach about a 90-degree angle. Try not to lean your upper body forward more than a few inches. You may want to move your arms forward for balance or stand next to a wall, counter, or other support. Straighten your legs to return to standing straight, then repeat 2-3 times a day.
Side leg raises
Lie on your side with your injured leg on top. Slowly raise your injured leg toward the ceiling. Hold this position for 10 seconds, then repeat this method 3-4 times a day.
Laying on the floor with the ends of a resistance band or tubing in each hand, bring your knees to your chest. Put the tubing across the bottoms of your feet and take up any slack in the resistance band. Afterward, while keeping your elbows on the floor and your hands by your chest, slowly press on both legs outward, leading with your heels until your legs are straight. Gently return to a bent-knee position before repeating this exercise 3-4 times a day.
While sitting on a chair with both feet on the floor hip-width apart, slowly raise one leg out in front of you until it’s level with the floor. Then, slowly lower the same leg back to the floor and repeat 2-3 times a day.
Stand tall with feet shoulder-distance apart at the base of a set of stairs. Next, shift your weight onto one foot. Place your right foot entirely on the step and press yourself up so that your body is up onto the step, placing the left foot next to the right foot on the stair. Slowly lower your left foot back to the floor and steady yourself. Continue this process with your right foot on the step as you repeat this method 2-3 times a day.
Alternative & Homeopathic Treatment
If you have mild to moderate bipartite patellar, you can often treat it at home. Here are some homeopathic treatments that can help you reduce and improve symptoms linked to this condition:
Some studies have shown that there are pain-relieving effects of a salve made of cinnamon, mastic, sesame oil, and ginger. They found the salve was just as effective as over-the-counter arthritis creams containing salicylate, a topical pain-relieving treatment.
This is an ancient Chinese form of mind-body exercise that improves balance and flexibility. Tai chi can help reduce pain and increase the range of motion. It also involves deep breathing and relaxation. These aspects may also help reduce stress and help you manage chronic patellar pain.
Willow bark extract
Some patients sometimes use willow bark extract for joint pain, as it may help relieve pain and inflammation. However, it is recommended to check in with your doctor before the usage of this extract.
Ginger extracts are available as supplements and ginger tea. These are used to help reduce arthritic pain.