Knee Injuries

Knee Injuries

What Are Knee Injuries?

While engaging in activities that involve physical exertion can be beneficial to an individual’s overall health, it can also place the individual at an increased risk for sustaining injury, particularly knee injuries. In 2010, the Centers for Disease Control conducted a survey of patient visits and found that nearly 10.4 million visits could be attributed to knee injuries.

The knee joint is one of the largest joints found within the body. It is a complex structure that is made up of several individual structures, which makes it particularly vulnerable to injury.

The structures that comprise the knee can be grouped into four main categories:

• Bone: The joint of the knee is formed by the junction of three leg bones. These bones include the femur, tibia, and patella.
• Ligaments: Ligaments are responsible for holding together the bones that comprise the knee joint. Collateral ligaments are found along the sides of the knee. Their function is to control sideways motion and aid in bracing the knee against unusual movement. Cruciate ligaments are found inside the knee joint. Their function is to control the back and forth movements of the knee.
• Cartilage: A slippery coating of articular cartilage protects the back of the patella, and the ends of both the tibia and the femur. Additionally, two pieces of protective cartilage known as menisci are found between the tibia and femur.
• Tendon: The muscles of the legs are connected at the knee joint by tendons.

Injury occurring to any of these structures of the knee joint can result in significant symptoms of pain and discomfort. In general, the type, location, and severity of pain will depend on the underlying source of the symptoms.

Some of the most commonly reported symptoms of knee pain include:

• Redness or swelling in the knee joint area
• Knee joint stiffness
• Warming sensations
• Knee joint weakness or instability
• Popping or crunching noise with movement of the knee joint
• Limited range of motion in the knee joint

It is important to contact your doctor if you have any of the following symptoms:

• Inability to bear weight on the injured knee
• Severe swelling in the knee joint
• Inability to extend or flex the knee
• Appearance of obvious deformity
• Knee instability or feeling that the knee is “giving out”
• Redness, swelling, and pain that is accompanied by fever

Causes of Knee Injuries

There are a number of injuries that can occur to the structures that comprise the knee joint.

• ACL injury: An ACL injury results when the anterior cruciate ligament (ACL), which connects the shinbone to the bone that comprises the thigh, is torn. This type of injury can occur as the result of changing direction hastily or landing improperly after a jump and are found to be most common among athletes.
• Meniscus tear: Twisting the knee while bearing weight can injure the protective pieces of cartilage found between the tibia and the femur, known as the menisci. Meniscal tears can also occur as the result of deterioration with advancing age.
• Dislocation: A knee joint dislocation occurs when the bones of the knee either partially or completely fall out of place. In some cases, the bones of the knee can become dislocated as the result of blunt trauma, such as sports-related contact, falls, or a motor vehicle accident. Some individuals may be born with abnormalities in the structure of the knee that predisposes them to knee dislocation.
• Bone fractures: The bones that comprise the knee can also become fractured as the result of blunt trauma, such as from falls or a motor vehicle accident. The patella is the most commonly broken bone within the knee, though the ends of the tibia and femur may also become fractured.
• Posterior cruciate ligament injury: The posterior cruciate ligament, found within the knee, can become injured as the result of trauma sustained at the front of knee while it is in the flexed position. This type of injury typically occurs as the result of a motor vehicle accident or sports-related contact.
• Collateral ligament injury: The collateral ligament, found along the side of the knee joint, can become injured as the result of trauma that pushes the knee sideways. This type of knee injury is among the least common.
• Tendon tear: The tendons that connect the muscles of the leg within the knee joint can become stretched, strained, and even torn. This type of injury can occur as the result of falls, landing awkwardly from jumping, or blunt force trauma.

Treatments for Knee Injuries

For many cases of knee injury, non-operative treatment techniques are recommended for managing symptoms. As soon as possible following a knee injury, patients are encouraged to follow the RICE method:

• REST: Rest the injured knee and apply weight only as tolerated
• ICE: Utilize cold therapy by applying ice for 15 to 20 minute intervals at a time
• COMPRESSION: Wrap the affected knee tightly with a compression bandage or brace
• ELEVATION: Elevate the affected knee to reduce swelling or inflammation

Over-the-counter (OTC) oral analgesics, such as non-steroidal anti-inflammatory drugs (NSAIDs), may be used to manage symptoms of pain and discomfort. For some cases of knee injury, physical therapy may be recommended. This type of treatment involves instruction on targeted stretches and other specialized exercises. These techniques are designed to improve flexibility of the joint and increase strength. In most instances, a knee injury patient can expect to visit with a physical therapist twice a week for approximately eight weeks.

For some instances of meniscal tears, surgical meniscal repair may be warranted, depending on the exact location of the tear. Patients presenting with moderate to severe meniscal tears along the outer edge of the meniscus are considered ideal candidates for this surgery. During this arthroscopic procedure, a small incision is made along the knee and the torn meniscus is repaired with sutures or anchors. In some cases, the torn part is clipped away. Recovery from surgery can take between four to six weeks.

Surgical repair may also be warranted in instances of torn ligaments or cartilage damage. During this procedure, the damaged tissue can be repaired using tissue grafted from other areas of the body. This procedure is generally performed with the aid of arthroscopy. Commonly performed procedures utilized to repair knee injuries include ACL reconstruction, collateral ligament repair or reconstruction, knee cartilage procedures, and patella stabilization. Recovery from this type of procedure can take between four to six months.


The knee is the largest joint in the body and is susceptible to a number of injuries. Typically, knee injuries occur as the result of blunt force trauma, such as from falls, motor vehicle accidents, or sports-related contact. In most instances of knee injuries, non-surgical conservative treatments may be appropriate in managing symptoms of pain and discomfort while the injured knee heals. In extreme instances, surgical repair may be the only option. Patients are encouraged to speak with their physician about the appropriate course of treatment for their injury.


  1. Bogunovic L, Matava MJ (2013) Operative and nonoperative treatment options for ACL tears in the adult patient: A conceptual review. Phys Sportsmed 41:33-40.
  2. Eggerding V, Reijman M, Scholten RJ, Meuffels DE (2014) Computer-assisted surgery for knee ligament reconstruction. Cochrane Database Syst Rev 8:CD007601.
  3. Guyver PM, Arthur CH, Hand CJ (2014) The acutely swollen knee. Part two – management of traumatic pathology. J R Nav Med Serv 100:186-192.
  4. Hohlweck J, Quack V, Arbab D, Spreckelsen C, Tingart M, Luring C, Rath B (2013) Diagnostic and therapeutic management of primary and recurrent patellar dislocations – analysis of a nationwide survey and the current literature. Z Orthop Unfall 151:380-388.
  5. Kaleka CC, Debieux P, da Costa Astur D, Arliani GG, Cohen M (2014) Updates in biological therapies for knee injuries: menisci. Curr Rev Musculoskelet Med 7:247-255.
  6. Kopkow C, Freiberg A, Kirschner S, Seidler A, Schmitt J (2013) Physical examination tests for the diagnosis of posterior cruciate ligament rupture: A systematic review. J Orthop Sports Phys Ther 43:804-813.