Primary Care Conference: Common Knee Injuries

Primary Care Conference: Common Knee Injuries

Knee Injury

Primary Care Conference: Common Knee Injuries. As I am attending a primary care conference this week, I thought it might be helpful to share a few examples of common knee injuries. I attended a helpful lecture on knee injuries that occur in children. Some occur in athletes, others are sustained during day-to-day activities. Without further ado, what are a few of these examples?

Prepatellar Bursitis

Case 1: A high-school boy comes into the clinical due to new onset left knee pain and swelling. He recently picked up a new job laying carpet and says that the knee pain prevents him from doing his job because he cannot kneel without feeling significant pain. The physical examination shows significant swelling over the front of the kneecap.

DIAGNOSIS: Prepatellar bursitis. The prepatellar bursa lies between the patella and the skin. This is lined with synovial tissue, which produces fluid. The job of this fluid is to decrease the friction between the bones around the knee. If the friction is chronic, the bursa responds by making more fluid. This leads to the swelling seen during the physical examination.

TREATMENT: The fluid should be aspirated and tested to make sure that nothing abnormal is in the fluid. If there are fat droplets on top of the fluid when it is removed, there is a fracture somewhere in the bones around the knee. This boy needs to modify his activity and take NSAIDs (such as ibuprofen) to relieve the pain and give the knee time to rest.

Dashboard Knee: Torn PCL

Case 2: A teenager recently got his driver’s license and was driving too fast on a local road. He rear-ended the car in front of him and comes in with a large effusion to his left knee. He states that his left knee struck the dashboard of his car in a violent manner. The child says that his knee swelled up immediately after the impact was sustained.

DIAGNOSIS: This is called dashboard knee, which is the colloquial term for a rupture of the PCL (see the mechanism above). The PCL is the strongest ligament in the knee. Its job is to restrain the knee from moving in a posterior manner (meaning that the femur slides backward relative to the tibia). A PCL rupture can also occur if someone falls on a flexed knee with the foot in a plantarflexed.

TREATMENT: If the child is an athlete, the PCL needs to be repaired surgically. Intense physical therapy will be needed to strengthen the muscles around the knee to prevent this from happening again. Of course, in the meantime, use NSAIDs and ice to reduce the swelling. Surgery cannot be performed until the swelling goes away.

Patellar Dislocation: A Dislocated Kneecap

Case 3: A college athlete was playing tennis on a clay court. He went to slide to collect a drop shot when he felt his knee buckle immediately. He dropped to the ground and he noticed an obvious deformity in his knee and was brought to the ED immediately. The patellar kneecap is obviously displaced laterally.

DIAGNOSIS: This is obviously a patellar dislocation. To confirm this, an XR is taken with a “Merchant’s” view. There are several ways that someone can dislocate their patella. Direct trauma is the most common mechanism with rotation around a fixed knee that is in flexion. There is a disruption of the medial retinaculum along with medial patellofemoral ligament disruption. An osteochondral injury to the patella and lateral femoral condyle are also often present.

TREATMENT: First, we need to make sure that all of the blood vessels around the knee are still intact. Then, orthopedics needs to be called to reduce the knee, aspirate the fluid, and take the patient to surgery. Recent literature advocates for immediate repair of the medial patellofemoral ligament. After this, intense physical therapy is needed to restore the function of the knee.

Torn ACL

Case 4: A high schooler is playing soccer and is competing for a ball. As he extends his leg to strike the ball, another player collides with him from the side. His parents say that his cleat was planted and he rotated as he fell. The child says that there was immediate pain and he could feel his knee “pop.” He also says that swelling started immediately after the injury.

DIAGNOSIS: This child has torn his ACL. Next, this child still needs radiographs to rule out an avulsion fracture of the lateral tibial plateau (a Segond Fracture). These two tend to go together. After this, an MRI will confirm an ACL tear.

TREATMENT: After the swelling has gone down, this child needs to be taken to surgery to repair his ACL. A repair is typically done by taking a small portion of one of his hamstrings to fashion a new ligament. After this, intense physical therapy is needed to strengthen the muscles around the knee. This will provide additional support for the new ligament and prevent an additional rupture. Those who have torn their ACL once are more likely to tear that same ACL in the future.

Contact a Local Pediatrician

Ultimately, the knee is an important joint and any child who has signs or symptoms of a knee injury needs to see a doctor. Some of these injuries could even require surgery. When this happens, the recovery process could be long. Because of this, it is vital for parents to speak with a pediatrician about any questions or concerns. Doctors are here to help!

David Randolph, MD

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