Patellar Fracture/Broken Kneecap
The patella or kneecap is a small bone at the front of the knee joint where the femur (thigh) and tibia (shin) meet. The patella protects the knee joint and acts as a stabilizing force connecting the muscles of the femur to those of the tibia. Any significant injury to the knee can result in a kneecap fracture.
A patellar fracture is simply a broken kneecap. This is a very common knee injury as a result of the location of the patella – right at the front of the knee. Significant trauma including a direct fall on the knee, sports injuries, especially in contact sports and motor vehicle accidents are often to blame. A patellar fracture can also occur if the quadriceps contracts violently while the knee is bent.
There are several types of patellar fractures that are more generally split into stable fractures – those in which the bone does not separate by more than 1 or 2mm; and displaced fractures in which the bones have separated to the point where the fracture will not heal properly without surgical intervention.
Patellar fractures can be further classified into transverse or vertical fractures. As the name suggests, these are single fractures that run the width or height of the patella, respectively. Comminuted fractures are where the bone breaks into three or more pieces. Patellar fractures that involve 2 or more pieces of the kneecap that are broken apart are unstable. Sometimes you can have a crack in the bone and the pieces are still together. In those cases, the kneecap fracture is stable.
Open fractures are those where the bone breaks through the skin or the injury is deep enough that it reaches the bone. Open fractures are a particular concern because infection is a very real possibility. Surgery is almost always necessary soon after an open fracture.
How Do I Know I Have a Patellar Fracture?
A patellar fracture is a very serious injury. Not only does the bone break, but the tendons connecting the thigh and shin muscles can also be affected. Therefore, most patients will experience significant pain, bruising and swelling. They will also have difficulty or inability walking and may not be able to straighten their leg.
Of course, the ultimate diagnosis must be made by a qualified orthopedic surgeon. During the examination, your surgeon will discuss medical history as well as the circumstances surrounding a recent injury or trauma to the front of the knee. During this time, we will also check for hemarthrosis, which is a collection of pooling blood within the joint that can cause additional pain and disability.
While we can often feel the fracture through the skin, an x-ray is used to make the diagnosis and see exactly how the bone rests. This allows your surgeon to understand more about the problem and develop an appropriate plan to treat it.
Nonsurgical Treatment for Patellar Fractures
Stable fractures, those in which the bone has not separated by more than 1 or 2 mm, can often be treated using non-surgical means. Typically, the knee is immobilized using a splint or a cast with the hope that the bones heal properly without surgery. Immobilization may last anywhere from a few to several weeks before the patient can put significant weight on the knee. Along with any nonsurgical treatment comes a course of physical therapy. Physical therapy is crucial to strengthening the muscles around the knee, improving range of motion of the joint and reducing swelling and stiffness within the joint.
Surgical Treatment of Patellar Fractures
Surgical treatment is often indicated for displaced fractures, during which the bone has separated by more than 1 or 2 mm and cannot heal without intervention. Depending on the type of fracture, surgical intervention options may vary. As noted above, open fractures must be treated immediately to avoid the potential for a deep infection.
Transverse or vertical fractures – those where the kneecap has broken into two pieces are often fixed using screws and pins and adding tension wires to keep the bones close together. However, this kind of surgery is limited to fractures near the center of the kneecap. Screws and plates may also be used instead of tension wire.
For a comminuted, displaced fracture – one where the patella has split into three or more pieces, and the bones have separated, there are several potential options. Typically, however, smaller fragments of the patella are removed from the knee entirely. This often requires the tendon to be reattached to the remaining portion of patellar bone. This can be achieved using a combination of wires and screws. Only in very severe cases does the patella have to be removed entirely.
Long-Term Outcomes of Patellar Fractures
The outcome and prognosis of a patellar fracture largely depends on the severity of the break. Straightforward fractures that can be treated non-surgically tend to have the best outcomes. More complex breaks that require removal of patellar bone, may require longer recovery and outcomes are less certain. All surgical procedures on the knee can be made more successful by employing a highly experienced orthopedic surgeon and following a comprehensive physical therapy program after surgery.
Probably the most common of the concerns after patellar fracture surgery is posttraumatic arthritis, that may also result in chronic pain. Arthritis can occur after any injury to bone, and the kneecap is no different. Most patients do not experience severe arthritis – it is typically mild to moderate and is often alleviated with occasional pain medication and a knee brace. Patients may also experience some muscle weakness in the quadriceps – the muscles of the front of the thigh. Range of motion issues can be expected depending on the type and severity of the fracture. Patients tend to return to normal activity within six months after their procedure, but rare cases may require a longer recovery due to a more severe injury or more complex repair.
Most importantly, follow your postoperative instructions very carefully so that the knee can heal quickly and completely. For more information or to schedule a consultation with one of our orthopedic surgeons, please contact us.