Overview of a Blown out Knee Joint

The knee joint is often injured in sports activities and athletics and these injuries can be quite severe. In describing an injury to the knee, sometimes people use the words their knee was "blown out," but what exactly does that mean?

male soccer player on the ground holding his knee in pain
Terje Rakke / Getty Images

The truth is, I can't tell you exactly what that means. Saying someone has a blown out knee is the same as saying they had a bad knee injury or suffered a traumatic knee injury. It could mean a variety of things, some more severe than others, but simply saying a knee was blown out will not tell you exactly what happened or what the treatment and prognosis of the knee will be.

Knee Ligament Injuries

Most often when people are talking about sports-related traumatic knee injuries, they are describing knee ligament injuries. The four major knee ligaments are the most commonly injured and subsequently repaired. These include:

With severe sports-related injuries, it is not uncommon to sustain injuries to multiple ligaments, and often these occur in patterns such as the unhappy triad, a common football injury. In addition, other structures are sometimes injured, such as the meniscus or the posterolateral corner of the knee.

Knee Dislocations

In the most severe injuries, knee dislocations can occur. These are very severe injuries, that require evaluation in an emergency room as repositioning the knee can be difficult, and the possibility of nerve or blood vessel injury is high, making this a limb-threatening injury.

When a dislocation occurs, the bones of the lower extremity, the femur, and the tibia, lose contact with each other. When this occurs, the ligaments are always damaged, and the knee must be repositioned as quickly as is possible. Sometimes the dislocation can occur to the kneecap. Kneecap dislocations are not as severe as knee dislocations, but can cause significant ligament and cartilage damage and may require surgical treatment for repair.

Rehab From Knee Injuries

Following a severe traumatic knee injury, surgery is often required to repair damaged ligaments, remove cartilage fragments, or otherwise fix the damaged structures in the knee. Following knee surgery, rehabilitation can take months or longer. After professional athletes sustain a blown out knee joint it is not uncommon to miss 6-12 months of sports participation, and often this signals the end of an athlete's career.

Long-Term Problems From Knee Trauma 

One of the major concerns of severe sports-related injuries of the knee are the consequences for long-term knee problems. In fact, when I hear people use the phrase "blown out" knee, it is most commonly a middle-aged or older patient describing an injury that occurred decades before in their high school or college sports playing days.

People who sustain these traumatic knee injuries have a higher chance of developing arthritis in the knee joint later in life. Damage to the knee joint can lead to accelerated joint wear-and-tear and may require further treatment later in life. That said, some people with severe knee trauma can fully recover and avoid problems later in life. It's important after a severe sports-related injury to ensure that you receive proper treatment in hopes that your knee can fully recover both in the short-term and the long-run.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Johns Hopkins Medicine. Knee ligament repair.

  2. Dacombe PJ. Shelbourne's update of the O'Donoghue knee triad in a 17-year-old male Rugby playerBMJ Case Rep. 2013;2013:bcr0120125593. doi:10.1136/bcr.01.2012.5593

  3. Mohseni M, Simon LV. Knee dislocation. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing.

  4. Vaquero-picado A, Rodríguez-merchán EC. Isolated posterior cruciate ligament tears: an update of management. EFORT Open Rev. 2017;2(4):89-96. doi:10.1302/2058-5241.2.160009

By Jonathan Cluett, MD
Jonathan Cluett, MD, is board-certified in orthopedic surgery. He served as assistant team physician to Chivas USA (Major League Soccer) and the United States men's and women's national soccer teams.