Bipartite Patella

Bipartite patella is an orthopedic condition characterized by the presence of an accessory bone in the patella, also known as the kneecap. Unlike a fracture, which results from a traumatic injury such as a blow or a sudden contraction of the quadriceps muscle, bipartite patella is a condition that occurs during the development of this bone.

What is a bipartite patella?

The patella, or kneecap, is a small circumferential bone located in front of the knee, essential for the joint's extension movements and for protecting the knee. At birth, the patella is not yet ossified; its ossification nuclei begin to fuse from the age of three. This fusion occurs from the ineer portion to the periphery of the structure. In approximately 2% of the population, there is a failure in the fusion of the ossification nuclei, causing what we call a bipartite patella. In this condition, the unfused part of the patella appears as an accessory bone, connected to the patella by a synchondrosis, which is a type of joint filled with fibrocartilage.

Types of bipartite patella

Bipartite patella can be divided into 3 types, according to the location of the accessory bone fragment (Saupe, 1921):

Type I - inferior fragment (5% of the cases);

Type II - lateral fragment (20% of the cases);

Type III - superolateral fragment (75% of the cases).

bipartite patella saupe classification.jpeg

What the patient feels

Most patients with a bipartite patella do not have any symptoms in the knee and are only aware of the condition during an imaging exam. However, some individuals may experience symptoms, especially if there is inflammation in the area. This inflammation can occur due to mechanical overload on the accessory fragment and some of the most common symptoms include:

Pain in the front of the knee, especially during strenuous activities such as jumping, squatting and running;
Swelling and tenderness in the area;
Difficulty to perform movements such as squatting or climbing stairs;
Crepitation or clicking when moving the knee.

Diagnosis

The diagnosis of bipartite patella is usually made through a physical examination of the patient's knee and can be confirmed by imaging exams. X-rays are the most common method of visualizing the patella and identifying the presence of bone fragments. In some cases, MRI may be used to assess the extent of the condition, the level of inflammation, and to rule out other possible causes of knee pain.

Treatment

Patients who have asymptomatic bipartite patella, those who do not have any symptoms related to the condition, do not need to worry or undergo treatment.

Patients with symptomatic bipartite patella usually have satisfactory results with conservative treatments, that is, non-operative treatments. Conservative treatment options include:

Rest and activity modification: Avoid activities that aggravate symptoms.
Physical therapy: To improve pain and strengthen the muscles around the knee.
Medication: Non-steroidal anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation.
Use of orthoses: Knee braces or bandages for additional support during physical activities.

In cases in which symptoms persist even after non-invasive treatment, surgical intervention may be necessary. The most frequently performed procedure for the treatment of symptomatic bipartite patella is the removal of the accessory bone fragment. After surgery, the patient is usually referred to physical therapy and rehabilitation.

The result is usually good after treatment, with the possibility of a full return to normal activities.

Final Considerations

Bipartite patella is a rare condition that often goes unnoticed and does not cause significant problems. However, for those who experience pain or functional limitations, it is important to seek medical evaluation for an accurate diagnosis and appropriate treatment plan. With the right treatment, it is possible to manage symptoms and maintain a good quality of life by continuing to participate in normal activities, including sports.

If you suspect that you may have bipartite patella or are dealing with knee pain, see an orthopedic surgeon for a thorough evaluation. Proper information and care are essential to effectively managing this condition.