Knee injuries

Overview of knee injuries

Your knee joint is a complex and vulnerable joint. It bears your bodyweight, supports movement, and acts as a shock absorber. It’s also one of the most easily injured joints. In fact, millions of people each year see their doctor for a knee injury.

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Symptoms

Knee pain and swelling are the most common symptoms of any kind of knee injury. Other signs and symptoms include:

  • Difficulty moving the knee
  • Catching or locking of the knee
  • Stiffness
  • Warmth to the touch
  • Inability to fully straighten the knee

The knee may also be unstable, meaning it feels like your knee is loose or gives way when you use it. In fractures and dislocations, the knee may appear deformed or out of alignment.

Causes

Knee injuries typically result from a trauma of some kind. Often, the trauma affects more than one structure in the knee. High-energy trauma, such as car accidents and sports injuries, are usually responsible for fractures, dislocations, and ligament and tendon tears.

Other injuries, such as meniscal tears, tendonitis, and sprains, can occur either from acute trauma or from chronic overuse. Overuse places stress on the knee over and over again. This can eventually weaken the knee structures and lead to injury.

Types

Common knee injuries include:

  • Dislocation, when your patella (kneecap) slips out of place.
  • Fracture, when the bones of the knee experience high force impact and break.
  • Ligament tears, including the ACL (anterior cruciate ligament), affect the ligaments that connect your shinbone to your femur and are most common in people who play sports where they need to change direction quickly, like soccer.
  • Meniscus tears occur when you twist your knee suddenly while your weight is on it. The meniscus is a layer of cartilage that absorbs shock between your thigh and shin.
  • Tendonitis and tendon tears occur when one of the tissues that attach muscles to bones (tendons) become inflamed.

There are additional mechanical issues that can arise in your knee that stem from elsewhere, such as your hip or feet. If you have cartilage degeneration, you could have a piece of it floating around in your knee space. This is not generally an issue unless it starts rubbing or disrupts movement.

Risk factors

Several factors can put you at risk for knee injury:

  • Participating in sports with repeated pounding, jumping, pivoting, or high potential for falling make you susceptible.
  • Being overweight increases stress on your joints and puts you at higher risk of developing osteoarthritis, which increases the breakdown of joint cartilage.
  • Lacking muscle strength or flexibility increases your risk of injury, as strong muscles stabilize your joints and flexibility helps you maintain a full range of motion.

Prevention

While it is always possible to avoid a knee injury, there are concrete steps you can take to lower your risk:

  • Maintain a healthy weight
  • Practice correct form during sports and exercise
  • Take time for conditioning, to stay strong and flexible
  • Consider switching to low-impact sports like swimming

The information contained in this article is meant for educational purposes only and should not replace advice from your healthcare provider.