(Reuters Health) – Osteoarthritis of the knee is more common in people who’ve had injuries to the ligament or the cartilage that help stabilize the knee joint, a research review suggests.
Compared to people without knee injuries, individuals with injuries to the anterior cruciate ligament (ACL) were more than four times as likely to develop knee osteoarthritis, the study found. People with injuries to the meniscus cartilage alone or in combination with an ACL injury were more than six times as prone to osteoarthritis, researchers note in the British Journal of Sports Medicine.
The estimates are drawn from analyses of 53 previously published studies with more than 1 million participants, including about 185,000 with these knee injuries.
“The injury itself damages the tissue and complete recovery of the knee is rarely gained,” said lead study author Erik Poulsen of the University of Southern Denmark in Odense.
“Cartilage and ligaments have much poorer healing capabilities due to limited blood supply,” Poulsen said by email. “This change in structure changes the biomechanics of the joint and can lead to osteoarthritis. Further, the often-substantial trauma not only tears the ligament or the meniscus but also causes damage to the cartilage and bone.”
The results suggest that meniscal injuries in isolation or in combination with ACL damage may be an even more important risk factor for osteoarthritis than an ACL injury alone, the study authors conclude. Many patients had surgery for ACL injuries, and this also didn’t appear to be as big a risk factor as a meniscal injury.
Eleven studies involving roughly 185,000 people investigated ACL injuries. Patients in these studies were 28 years old on average at the time of injury.
Another 22 studies focused on meniscal injuries. These studies included about 83,000 people with an average age of about 38 at the time of injury.
In 25 studies examining combined ACL and meniscal injuries, patients were 31 years old, on average, at the time of injury.
Most studies followed patients for at least a decade, and the risk of osteoarthritis associated with knee injuries appeared to increase over time.
A leading cause of pain and disability in older adults, knee osteoarthritis occurs when flexible tissue at the ends of bones wears down. While it can’t be cured, physical therapy or anti-inflammatory medications are often prescribed to relieve pain and improve mobility.
One limitation of the analysis is that some of the studies lacked data on whether patients had osteoarthritis before their knee injuries, the study authors note.
However, several factors can increase the risk of osteoarthritis after a knee injury, including muscle weakness, altered biomechanics, poor functional capacity like decreased ability to hop or jump, and being overweight or obese, said Adam Culvenor, a sports medicine researcher at La Trobe University in Melbourne, Australia.
“Returning to sport after injury doesn’t seem to be associated with increased risk of osteoarthritis longer term, so we can educate our patients about the importance of optimizing muscle strength and function and maintaining a healthy weight and physical activity,” Culvenor, who wasn’t involved in the study, said by email. “But It is important to note that, to date, no data exists from high quality, randomized controlled trials to show that post-traumatic osteoarthritis can be prevented.”