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Knee Injury

Dr. Leonie Prao diagnosing a patient's knee injury.

The knee is the largest joint in the body which means it’s also easily injured. And knee injuries can seriously impact your quality of life, especially if you’re an athlete.

Effective treatment begins with an accurate diagnosis, so it’s important to see a knee doctor if you have sudden pain in your knee after an injury. Our MedStar Orthopaedic Institute specialists are experts in diagnosis and treatment. In fact, our orthopedists treat professional sports teams in the region, including the Baltimore Ravens, Baltimore Orioles, and Washington Capitals.

When you choose us for your knee care, you’ll benefit from advanced diagnostic technology, minimally invasive treatments, and the same personalized attention we offer the pros.

Not sure what you need or who to see? Call us at 877-34-ORTHO to find a knee specialist in the Baltimore region.

Below are some common knee injuries.

For more information or to schedule an appointment with a knee specialist, please call:


The anterior cruciate ligament (ACL) is one of the four main ligaments that connect the femur (thighbone) to the tibia (shinbone). The ACL is fibrous, like a rope, and along with the other ligaments, it holds the knee together and provides rotational stability.

An ACL tear is a common injury for those involved in competitive sports or recreational physical activity, and it happens most commonly to female athletes. It often results from abrupt changes in movements, such as twisting or pivoting. Sudden stops where the foot and lower leg are planted and the top part of the knee keeps moving forward may also cause the ligament to partially or completely tear.

An injured ACL may result in some or all of the following symptoms:

  • An audible “pop” or snapping upon injury
  • Immediate swelling in the knee that doesn’t go away
  • Instability in the knee that can cause it to give out
  • Inability to bear weight
  • Significant pain that does not go away
  • A feeling of fullness in the knee

You may not need surgery following an ACL injury if you are elderly and less active. If the overall stability of your knee is healthy and you have a low activity level, your knee specialist may recommend non-surgical options, such as physical therapy and bracing to stabilize the knee. For athletes, however, ACL surgery is commonly recommended.

Learn more about ACL repair surgery.

A fracture is a partial or complete break in the kneecap which may occur after a direct fall or blow to the knee. Symptoms may include:

  • Bruising and tenderness
  • Decreased range of motion
  • Difficulty straightening the injured knee
  • Immediate and severe knee pain
  • Swelling

If you think you have a fracture, an orthopedist will use imaging technology, such as x-ray, to confirm your knee pain diagnosis. If the pieces of your kneecap are not out of place, your knee doctor may recommend a cast or splint to prevent movement while your knee heals. However, for more severe breaks, you may need surgery.

Learn about knee surgery.

Knee instability is the sensation of the knee giving out and is usually the result of an injury to a ligament. Injuries to one or more ligaments can lead to the two sides of the joint not being held tightly enough in position.

Usually, symptoms of instability occur with twisting or side-to-side movements. This may occur in sports activities or with simple tasks such as twisting your knee to get in and out of a car. It is also possible for people to experience instability symptoms with injuries that cause knee pain.

Nonsurgical treatments for knee instability can include physical therapy to strengthen the muscles around the knee joint and knee braces to better support the knee joint. Often, however, surgical treatment may be needed to restore the normal structure of the knee joint.

Learn about knee surgery.

Knee swelling can make the knee feel unstable by increasing the space between the thighbone (femur), shinbone (tibia), and kneecap (patella). Also called “water on the knee,” knee swelling can be caused by infection, inflammation, and/or a variety of knee injuries, including:

  • Ligament tears
  • Meniscus tears
  • Kneecap dislocations
  • Fractures

Many causes of knee swelling respond well to nonsurgical treatment, such as rest, ice, physical therapy, and anti-inflammatory medications. In some cases, however, the problem causing the swelling may need to be addressed surgically.

Learn about knee surgery.

The lateral collateral ligament (LCL) is located on the outside of the knee and connects the thighbone to the shinbone. LCL injuries are common knee injuries that occur when there is a complete or partial tear to the LCL after direct trauma to the inside of the knee. They frequently occur alongside other knee ligament injuries, including ACL and PCL tears.

An LCL injury can result in pain and swelling, as well as:

  • Decreased range of motion
  • Inability to walk
  • Popping sound at the time of injury

Your orthopedist may order an x-ray or MRI to diagnose an LCL injury and treatment will vary based on the severity of the tear. Nonsurgical treatment options may include physical therapy as well as icing the knee, anti-inflammatory medication, and/or a knee brace or crutches to immobilize the knee.

Most LCL injuries can be treated at home, but if you have a severe tear, you may need surgery to relieve pain and restore stability in your knee.

The knee meniscus is a piece of cartilage that serves as a shock absorber between the ends of the leg bones. It also distributes body weight across the knee joint.

Meniscus tears are often caused by sudden twisting or rotating, such as an abrupt change of direction while running. Aging can also increase your risk of a meniscus tear. Sometimes a meniscus tear occurs at the same time as an injury to the ACL, causing severe pain, swelling, and a feeling of the knee “catching”.

If you have a minor meniscus tear, nonsurgical options such as physical therapy and strengthening exercises may relieve your pain. However, severe tears typically require surgery to replace or repair the torn meniscus. Most procedures can be performed using minimally invasive arthroscopy techniques that allow shorter hospital stays and decreased recovery times.

Learn about knee surgery.

Jumper’s knee is an overuse injury to the patellar tendon that may cause knee pain from running or jumping frequently on hard surfaces. The patellar tendon connects your kneecap to your shinbone. With repeated stress, it may become inflamed, causing pain around the patellar tendon.

Activity makes it hurt worse and it may be difficult to even stand up from sitting or take the stairs. You may also have knee pain from squatting. Jumper’s knee symptoms may be similar to other knee injury symptoms, so it’s important to seek treatment to receive an accurate diagnosis.

The best way to treat jumper’s knee is to rest, ice, and elevate the knee. While you should stop any activity causing the injury, stretching and strengthening exercises may help it heal.

The posterior cruciate ligament (PCL) is one of the four main ligaments that connects your thighbone to your shinbone. Together, the ACL and PCL form an “X” over the center of the knee.

A PCL injury occurs when the ligament stretches or tears. This may occur if your knee hits the dashboard during a car accident or if you fall hard on a bent knee when playing sports. While less common than an ACL injury, a PCL injury can cause mild to moderate pain, swelling, and instability. Many times, people don’t realize they have a PCL injury until later on.

A knee injury specialist may use imaging tests to diagnose the severity of the injury, such as an x-ray or MRI. Depending on the severity of your PCL injury, you may be able to return to activity after nonsurgical treatment, such as rest, ice, compression, elevation, and physical therapy. For cases where the PCL has pulled away from the bone, you may need a knee surgeon to reattach the ligament to the bone with a screw in a procedure called knee arthroscopy.

Learn about knee arthroscopy.

Runner’s knee is a catchall term used to describe a variety of conditions that may cause dull, aching pain in or around the kneecap. Also known as chondromalacia, runner’s knee is common in patients who experience knee pain from running. It can also be caused by any activity that puts repeated stress on the knee joint.

Symptoms may include pain, swelling, and popping in the knee. A knee specialist may use imaging tests along with a thorough physical exam to diagnose runner’s knee. Typically runner’s knee is treated nonsurgically, and rest, ice, and elevation can help.