Why Knee Arthritis Is Likely to Develop After an ACL Tear

Knee ligament injuries can be devastating injuries for a young athlete. Often causing prolonged absences from sports teams, significant rehabilitation, and interruption to a normal lifestyle, a torn knee ligament is an injury feared by almost any young athlete. However, most athletes, and their parents, coaches, and fans are worried about getting back to activity, not what might happen a decade or later. Unfortunately, the fact is, that the worst may be yet to come. New research is shedding light on how young athletes who have knee ligament injuries are more likely than not to develop arthritis of their joint within a decade of their injury.

Woman playing soccer in a field outside
Klaus Vedfelt / Getty Images

Knee Ligament Injuries

There are four major knee ligaments, the two collateral ligaments on the sides of the knee, and the two cruciate ligaments that cross in the center of the knee. Most research investigating arthritis following knee ligament injuries has been on athletes who have torn their anterior cruciate ligament (ACL).

The ACL is an important ligament at preventing sensations of instability or 'giving-out' of the knee when performing a cutting or pivoting maneuver to change direction. ACL tears usually require surgical treatment, especially for athletes who participate in high-risk sports that require these sudden changes in direction as part of participation.

The surgery for a torn ACL is to make a new ligament, called a reconstruction, usually by taking tendon or ligament from somewhere else in the body. The success of surgery is generally good, although not perfect. Most athletes are able to return to sports activities after surgical reconstruction. However, the recovery is long and difficult, with athletes being out for a minimum of 6 months, and sometimes up to a year.

Arthritis of the Joint

Knee arthritis is a common problem, but most often associated with an elderly population. The most common type of arthritis is called osteoarthritis and is often referred to as wear-and-tear arthritis of the knee. When osteoarthritis occurs in the knee joint, the normally smooth, cushioning surface of the joint is worn away, leaving rough, exposed bone. The condition causes symptoms of pain, swelling, and deformity of the joint. Over time, the condition may worsen to a point that knee replacement may become an option.

As mentioned, knee arthritis is typically a condition of aging. Most people with arthritis are in their 60s or older. There are some risk factors for developing arthritis that can make the condition occur earlier in life. One of those risk factors is trauma to the knee, and a common type of traumatic injury is a knee ligament injury. Orthopedic surgeons have long known that people who tear their knee ligaments, including the ACL, are more likely to develop arthritis, but knowing how commonly and how soon this might occur was unclear.

A 2017 study found that about 75 percent of people who underwent ACL reconstructive surgery had arthritis findings on x-rays of their knee within 10-15 years of the time of surgery. This is a frightening finding, considering many ACL tears are treated in the teens and twenties of young athletes. These young people are then facing the prospect of managing knee arthritis as soon as in their 30s, a time when thoughts of arthritis are seldom on people's minds. Risk of developing arthritis is especially high in young people who also damage the meniscus cartilage or articular cartilage, rather than those who have isolated ACL tears.

The exact cause of the arthritis is not completely understood, but it is likely a few different problems. First, the initial injury can damage joint cartilage in a way that cannot be seen. However, cartilage has little ability to repair itself, and the damage can become more apparent over time. Second, the mechanics of the knee may change after reconstructive surgery. While surgical techniques are being developed to better achieve normal knee mechanics after reconstruction, the benefit of these changes is not entirely clear.

How to Prevent It

It is very clear that the best way to prevent early arthritis is to prevent ACL injuries and other knee ligament injuries. This is a subject of a lot of research investigating methods to lower the likelihood of ACL injury. There are promising results from some of these methods, but no prevention program will eliminate all ACL tears. Furthermore, if you've read this far, it's likely you or someone you care about already is managing a knee ligament tear.

Surgical reconstruction is felt to be a good method to prevent further damage to the joint. Every time the knee gives out, there is a risk of further cartilage damage in the joint. Therefore, many surgeons advise ACL surgery to prevent further damage in the knee. The benefit of bracing the knee is a subject of debate, but ACL braces have not been shown to improve results or prevent arthritis after having had ACL surgery.

Future Developments

As with many medical problems, there is a lot of investigation about how to improve the results for young athletes who injured knee ligaments. There are many who feel they have found ways to lower the likelihood of arthritis development, but the long-term effectiveness of these ideas has not been proven. Some investigations include:

  • Improving the Mechanics of ACL Reconstructive Surgery: Some new surgical techniques have been developed to better replicate normal ACL anatomy or even repair the damaged ACL. Double-bundle ACL reconstruction and bridge enhanced ACL repair are some of these techniques, but if these are better than standard ACL reconstructive surgery is not known.
  • Changing the Biology of the Joint After Injury: After an injury to a joint, such as a ligament tear, the body releases a variety of chemical signals within the joint. Altering the body's response to ensure damage does not progress, and healing is optimal, is an area of investigation.
  • Preventing ligament Injuries: Many investigations have been focused on understanding why some people tear their knee ligaments, and what can be done to prevent those injuries. Focusing on neuromuscular training, something called dynamic control of the extremity has been shown to help prevent knee ligament injury.

A Word From Verywell

Knee ligament injuries such as ACL tears are serious injuries that cause discomfort and time away from sports. Recovery from these injuries may require surgery and prolong rehab efforts. And if that's not enough, the long term prognosis may not be good, with most people developing arthritis within a decade of injury. Future research is aimed at modifying the risk of developing arthritis and preventing ligament injuries from occurring at all.

9 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. Paschos NK. Anterior cruciate ligament reconstruction and knee osteoarthritisWorld J Orthop. 2017;8(3):212–217. Published 2017 Mar 18. doi:10.5312/wjo.v8.i3.212

  2. Madaleno FO, Santos BA, Araújo VL, Oliveira VC, Resende RA. Prevalence of knee osteoarthritis in former athletes: a systematic review with meta-analysisBraz J Phys Ther. 2018;22(6):437–451. doi:10.1016/j.bjpt.2018.03.012

  3. Friel NA, Chu CR. The role of ACL injury in the development of posttraumatic knee osteoarthritisClin Sports Med. 2013;32(1):1–12. doi:10.1016/j.csm.2012.08.017

  4. Zhang Y, Jordan JM. Epidemiology of osteoarthritisClin Geriatr Med. 2010;26(3):355–369. doi:10.1016/j.cger.2010.03.001

  5. Cinque ME, Dornan GJ, Chahla J, Moatshe G, Laprade RF. High Rates of Osteoarthritis Develop After Anterior Cruciate Ligament Surgery: An Analysis of 4108 PatientsThe American Journal of Sports Medicine. 2017;46(8):2011-2019. doi:10.1177/0363546517730072

  6. Ratzlaff CR, Liang MH. New developments in osteoarthritis. Prevention of injury-related knee osteoarthritis: opportunities for the primary and secondary prevention of knee osteoarthritisArthritis Research & Therapy. 2010;12(4):215. doi:10.1186/ar3113

  7. Malahias MA, Chytas D, Nakamura K, Raoulis V, Yokota M, Nikolaou VS. A Narrative Review of Four Different New Techniques in Primary Anterior Cruciate Ligament Repair: "Back to the Future" or Another Trend?Sports Med Open. 2018;4(1):37. doi:10.1186/s40798-018-0145-0

  8. Mahapatra P, Horriat S, Anand BS. Anterior cruciate ligament repair – past, present and futureJournal of Experimental Orthopaedics. 2018;5(1). doi:10.1186/s40634-018-0136-6

  9. Sugimoto D, Myer GD, Barber Foss KD, Pepin MJ, Micheli LJ, Hewett TE. Critical components of neuromuscular training to reduce ACL injury risk in female athletes: meta-regression analysisBr J Sports Med. 2016;50(20):1259–1266. doi:10.1136/bjsports-2015-095596

Additional Reading
  • Oiestad BE, Holm I, Aune AK, Gunderson R, Myklebust G, Engebretsen L, Fosdahl MA, Risberg MA. "Knee function and prevalence of knee osteoarthritis after anterior cruciate ligament reconstruction: a prospective study with 10 to 15 years of follow-up" Am J Sports Med.

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.