Common Knee Injuries

The Knee

The knee joint is formed where the lower end of the femur bone meets the upper end of the tibia bone. A complex and delicate arrangement of cartilage, ligaments and tendons work in harmony to allow us to bend and straighten the knee.

Common Knee Injuries

The most frequent knee injuries encompass tears of soft tissues (such as ligaments and the meniscus), fractures, and dislocations. Often, multiple structures within the knee are affected simultaneously.

Key signs of a knee injury include pain and swelling. Additionally, the knee may catch or lock. Some injuries, like an ACL tear, can cause instability, making it feel as though your knee is giving way.

Anterior Cruciate Ligament (ACL) Injuries

anterior cruciate ligament ACL injury illustration

What is the ACL?

The anterior cruciate ligament, commonly known as the ACL is a ligament in the knee, which prevents the tibia from rolling forward of the femur injury to the ACL. Results in knee instability, which can result in irreversible damage to the joint leading to arthritis.

The anterior cruciate ligament is frequently injured during sports activities, especially in athletes involved in cutting and pivoting sports like soccer, football, and basketball. Rapidly changing direction or landing improperly from a jump can result in an ACL tear.

Approximately half of all ACL injuries also involve damage to other knee structures, such as articular cartilage, the meniscus, or other ligaments.

Posterior Cruciate Ligament (PCL) Injuries

Posterior Cruciate Ligament PCL Injury

What is the PCL?

The posterior cruciate ligament (PCL) is one of the key ligaments in the knee that connects the femur (thighbone) to the tibia (shinbone). It helps stabilize the knee, particularly by preventing the tibia from moving too far backward.

PCL Tear

The posterior cruciate ligament is often injured during high-impact activities or accidents. PCL injuries are more likely to occur in athletes participating in contact sports like football and rugby or in motor vehicle accidents. A PCL tear can result from a direct blow to the front of the knee or from hyperextending the knee.

Many PCL injuries occur along with damage to other knee structures, such as the articular cartilage, meniscus, or other ligaments.

Collateral Ligament Injuries

Collateral Ligament Injuries

What are Collateral Ligaments?

Collateral ligaments are key stabilizers of the knee joint, located on its sides. The medial collateral ligament (MCL) is on the inner side of the knee, while the lateral collateral ligament (LCL) is on the outer side. These ligaments control the sideways motion of the knee and brace it against unusual movement.

Injuries to Collateral Ligaments

Injuries to the collateral ligaments are usually caused by a force that pushes the knee sideways, often resulting from contact injuries.

  • MCL Injuries: These are commonly sports-related and usually caused by a direct blow to the outside of the knee.
  • LCL Injuries: These occur less frequently and typically result from blows to the inside of the knee that push it outwards.

Many. collateral injuries occur along with damage to other knee structures, such as the articular cartilage, meniscus, or other ligaments.

Meniscal Tears

Meniscus Tear

What is the Meniscus?

The meniscus is a C-shaped piece of cartilage located in the knee joint, acting as a cushion between the femur (thighbone) and tibia (shinbone). Each knee has two menisci, one on the inner side (medial meniscus) and one on the outer side (lateral meniscus). The menisci help to absorb shock and stabilize the knee.

Meniscal Tears

Acute meniscal tears often occur during sports activities involving twisting, cutting, pivoting, or being tackled.

Meniscal tears can also result from arthritis or aging. As the menisci weaken with age, even an awkward twist while getting up from a chair can be enough to cause a tear.

Many PCL injuries occur along with damage to other knee structures, such as the articular cartilage, meniscus, or other ligaments.

Tendon Tears

patellar tendinitis illustration

What is a Tendon?

A tendon is a tough, flexible band of fibrous tissue that connects muscles to bones, enabling movement and providing stability to joints.

Tendon Tears

The quadriceps  and patellar (knee cap) tendons can be stretched and torn. Although anyone can injure these tendons, tears are more common among middle-aged individuals who engage in running or jumping sports. Common causes of knee tendon injuries include falls, direct force to the front of the knee, and landing awkwardly from a jump.

Patellar Tendon Tear

A patellar tendon tear occurs when the tendon connecting the kneecap to the shinbone gets torn. This injury can happen due to falls, direct hits to the front of the knee, or awkward landings from a jump. It often causes pain and makes it difficult to straighten the knee.

Quadriceps Tendon Tear

A quadriceps tendon tear happens when the tendon connecting the thigh muscles to the kneecap gets torn. This injury usually occurs during activities that involve running or jumping, especially in middle-aged people. It can result in pain and trouble extending the leg.

Fractures

Patela fracture

Patellar Fracture

The most commonly broken bone around the knee is the patella (kneecap). The ends of the femur (thighbone) and tibia (shinbone) where they meet to form the knee joint can also be fractured. Many knee fractures are caused by high-energy trauma, such as falls from significant heights and motor vehicle collisions.

Distal Femur (Thighbone) Fractures of the Knee
Fractures of the Proximal Tibia (Shinbone)

Dislocation

Dislocated Knee

What is a Dislocation?

A dislocation occurs when the bones of the knee move out of their normal positions, either fully or partially. This can involve the femur and tibia being forced out of alignment, or the patella slipping out of place.

Dislocations can be caused by structural abnormalities in the knee. In people with normal knee structure, dislocations are usually the result of high-intensity trauma, such as falls, motor vehicle accidents, or sports-related impacts.