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Males At Increased Risk Of Osteoarthritis After ACL Injuries

Delay of up to a year in reconstructive surgery does not increase risk of cartilage lesions - a strong predictor of osteoarthritis

Male athletes are at increased risk of cartilage lesions in anterior cruciate ligament (ACL)-injured knees, placing them at higher risk of developing the debilitating joint condition osteoarthritis (OA), says a new research paper presented at the American Orthopaedic Society for Sports Medicine's 2011 Annual Meeting in San Diego.[1]

The study's authors speculated that the increased overall risk of cartilage lesions in males compared to females they found might be explained by higher levels of energy involved when the ACL tears in males. Because males on the average have higher body weight and muscle mass than females, the energy and risk of co-injuries to the joint might increase, resulting in more severe injuries in males. 

Another contributory explanation of the overall gender difference might be the trauma mechanism itself, as non-contact injuries are found to be a more frequent injury mechanism in females than in males, although a 2013 study[2] of ACL injuries among high school athletes in five boys' sports and four girls' sports, while finding that a slightly higher percentage of girls (47.2%) than boys (40.5%) sustained an ACL injury by no contact, the difference was not statistically significant.

Other risk factors for OA

Consistent with previous studies, the Norwegian-Swedish study found that age and previous knee surgery were also risk factors for full-thickness cartilage lesions in ACL-injured knees.

On whether early or delayed surgery is the better course, the study found that the a delay to reconstructive surgery did not increase the risk of developing full-thickness cartilage lesions,  as long as surgery occurred within 12 months of injury.  The study thus supports those who argue for a delay in surgery to allow restoration of strength, range of motion and reduction in swelling.  

"The present study suggests that ACL reconstruction can be awaited until adequate post-injury rehabilitation is achieved and up to 12 months after injury without significant risk of new full-thickness cartilage lesions [during that period]," wrote lead author Jan Harald Roetterud, MD, of  Akershus University Hospital in Lørenskog, Norway. That advice, however, came with a caveat: the study "says nothing about the effect of timing of surgery on later OA development. To evaluate this, a control group of non-operated ACL injured individuals and follow-up of those operated are needed."

Early surgery still recommended for kids under 14

Commenting on the study, Dr. Darren Johnson, Chairman of the Department of Orthopedic Surgery and Director of Sports Medicine at the University of Kentucky, noted that "what the study does not say is the activity level of the patients that delay surgery, in other words, are they playing sports without surgery.  If an athlete has a torn ACL and nothing else is torn - which is rare - choosing to return to sports without surgery puts the knee at risk of meniscal and articular cartilage injuries, which are often irreversible injuries in terms of the potential for OA and adverse outcomes down the road.  

If the athlete chooses early surgery and the menisci and articular cartilage are uninjured at the time of surgery, the athlete has a greater chance of not developing OA down the road than an athlete who delays surgery, gets a meniscal tear or articular lesion, and then decides to have it fixed," Dr. Johnson said, noting the finding of an earlier study that delaying surgery to repair a torn ACL in young athletes under the age of 14 significantly increases the risk of irreparable joint damage.

"Parents should understand that early reconstruction of the ACL, before any other damage to the knee, gives their child the best chance of a good outcome in the future.  Once other structures in the knee are damaged, the final outcome may not be as good, no matter what the surgeon does at the time of reconstruction." 

"Telling kids in this age group [who have torn ACLs] to be careful simply does not work, " says Dr, Johnson, "because they do not appreciate the ramifications of their injury and the problems created if they re-buckle their knee."

"The bottom line, even for young kids, is that delaying ACL surgery and reconstruction puts an athletically or even a normally active teenager at significant risk for re-injury, and, most importantly, for injury to other structures in the knee," says Dr. Johnson.

Degenerative changes common

Knee trauma leading to anterior cruciate ligament (ACL) injuries are common, especially in the young athlete, often resulting in major knee problems for the individual and large costs for society. Treatment typically involves ACL reconstruction to relieve this pressure and hopefully protect the cartilage.  Additional stress on cartilage around the knee following an ACL injury can cause full-thickness lesions (a hole or rough spot in the cartilage of the knee).

Studies show that such lesions, together with injuries to the menisci (the rubbery, C-shaped discs - one at the outer edge of the knee and one at the inner edge - that cushion the knee) are strong predictors of degenerative changes in the ACL injured knee.

The reported long-term risk of osteoarthritis (OA) after ACL injury and subsequent ACL reconstruction varies considerably. Long-term follow-up studies at 6-14 years after ACL injury of both female and male soccer and team handball players reveal high rates of OA and severely impaired quality of life due to knee-related symptoms, problems that effect even young athletes. 

Study details

Researchers examined data from 15,783 patients (aged 8-69 years, median age 26 years) undergoing primary ACL reconstructions between 2005 and 2008. Of these patients, 1,012 (6.4%) had full-thickness cartilage lesions, with 372 of the total occuring in females (5.6%) and 640 in the male population (7%).

"The goal of this type of research is to continually identify risk factors for injury," Roetterud commented. "With this information we will hopefully be able to improve prevention and treatment, as well as provide new guidelines for an athlete's return to sports."

Source: American Orthopaedic Society for Sports Medicine (AOSSM)

1. Rotterud JH. Impact of Gender and Sports on the Risk of Full-Thickness Articular Cartilage Lesions in Anterior Cruciate Ligament Injured Knees: A Nationwide Cohort Study from Sweden and Norway of 15,783 Patients.  Am.J  Sports Med. 2011 (accepted for publication).

2. Joseph AM, Collins CL, Henke NM, Yard EE, Fields SK, Comstock RD. A Multisport Epidemiologic Comparison of Anterior Cruciate Ligament Injuries in HIgh School Athletics.  J Athl Tr. 2013;48. DOI:10.485/1062-6050-48.6.03 (epub November 11, 2013). 

Updated and revised November 14, 2013