Issue: February 2012
February 01, 2012
4 min read

Play at 1 year does not predict midterm return to sports after ACL reconstruction

Issue: February 2012
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Researchers in Australia have concluded that 12-month follow-up may be too early to analyze return to sport outcomes after ACL reconstruction surgery, as most patients have not returned to pre-injury levels of participation by that time.

The average follow-up for patients was at 39 months.

Although 93% of patients attempted some level of sport between 2 years and 7 years after ACL reconstruction, researchers found less than half of patients had returned to play at pre-injury levels at 12 months.

“We have shown that people continue to return to sport after 12 months postoperatively. However, we did not find a relationship between participation at 12 months and participation at 39 months in this study,” study author Clare Ardern, a PhD candidate from the La Trobe University in Victoria, Australia, told Orthopedics Today. “This suggests that athletes may not maintain their sports participation over time.”

The research, which appears in the American Journal of Sports Medicine, showed that 45% of the 314 patients returned to pre-injury sports levels at a mean 39-month follow-up, while 29% had returned to competitive sports. The investigators noted that patients were just as likely to return to pre-injury levels at 2 years to 7 years, despite whether they were participating in sports at 12 months.

“When interpreting these results it is important to consider the relatively broad follow-up range of 2 to 7 years,” Ardern said. “This may raise the question of whether routine annual or biannual follow-ups might be the best way to thoroughly track return to sport rates in this population.”

Ardern suggested there might be other reasons why patients are not returning to competitive sports and that further study is needed to fully understand the situation.

“We do not understand enough about the reasons why people do not return to playing sport at the level they did before they were injured,” she said. “There are some studies that suggest that people might be worried about re-injury to their knee, so they choose to return to a less strenuous type of sport or give up sport all together.” She added that family commitments, lifestyle and occupational factors could also contribute to this decrease in participation.

She and other researchers are conducting a study to investigate whether psychological factors, such as fear and reduced confidence, influence the likelihood of returning to sport after surgery. – by Jeff Craven

  • Ardern CL, Taylor NF, Feller JA, Webster KE. Return-to-sport outcomes at 2 to 7 years after anterior cruciate ligament reconstruction surgery. Am J Sports Med. 2012; 40:1:41-48. doi:10.1177/0363546511422999.
  • Disclosure: Ardern has no relevant financial disclosures.


Freddie H. Fu, MD, DSc(Hon), DPs(Hon)
Freddie H. Fu

In the article “Return-to-sport outcomes at 2 to 7 years after anterior cruciate ligament reconstruction surgery,” Ardern et al presented results that contrast with the usual report surgeons give to patients saying that they will return to play in 6 months with a success rate of 95%.

Return to sports depends on many different factors including surgical technique, patient’s physical condition, psychological factors and aspects related to age and work. Despite being a good barometer of patient’s physical and mental capacity, the return to play itself cannot predict a true good surgical outcome and does not necessarily define treatment success. Patients can play even with a torn ACL at times. Other factors should be assessed too, such as, “How long are patients able to maintain playing at their pre-injury levels?” Ultimately, development of degenerative changes of the knee should also be assessed. By considering return to play as the main outcome tool, surgeons, coaches, family and patients potentially place the reconstruction at risk when they strive to achieve this goal as quickly as possible. In doing so, they may neglect important aspects during patients’ rehabilitation such as proper graft healing and maturation.

It should be highlighted that 42% of the study patients did not complete the survey, meaning that “real” return to play rate may be even lower. These numbers clearly show that we are overestimating the efficacy of our current surgical treatment. In Pittsburgh, we are slowing down the rehabilitation process and trying to look more objectively to graft healing using MRI instead of only addressing muscle strength and subjective outcome measurements when releasing patients to return to play, which takes most of the time 9 months to 1 year.

In the future, other objective assessment such as biomarkers should be available to evaluate graft healing. There is variation among patients and, as in our surgical approach, the decision of “return to sport” needs to be individualized.

Only high rates of follow-up (higher than 80%) associated with objective assessment tools can truly determine outcome success, which is certainly much less than we are used to advocating. Research such as this should continue to truly improve ACL reconstruction results.

— Freddie H. Fu, MD, DSc(Hon), DPs(Hon)
Orthopedics Today Editorial Board member
University of Pittsburgh
Disclosure: Fu has no relevant financial disclosures.


The goal of ACL reconstruction is to restore stability to the knee and allow return to sport. In their recently published study, Ardern et al found that 45%of patients returned to their pre-injury level of activity and 29% were playing competitive sports.

As surgeons, we generally tell patients prior to ACL reconstruction that we expect them to return to their pre-injury activity level. In fact, a common indication for ACL reconstruction is to allow return to the sport that the patient was participating in prior to the injury. The research presented by Ardern et al indicates that this may not always be the case.

The mean age of their patients at the time of surgery was approximately 28 years of age. Age was found to be a significant predictor of return to sport, with younger patients returning to their pre-injury level at higher rates. In addition to the physiologic effects of age on one’s ability to participate in sport, older patients may have job, family or other life circumstances that limit their ability to participate in athletics after ACL reconstruction. As orthopedic surgeons, we must keep these considerations in mind when advising patients.

— Robert G. Marx, MD
Orthopedics Today Editorial Board member
Professor of Orthopedic Surgery Hospital for Special Surgery
New York
Disclosure: Marx has no relevant financial disclosures.