One of the observations that I have made during my years in academic medicine is that the more popular a topic appears to be in the literature, the less likely we are to really understand it. After all, if we need to write about it so much, it must mean that there is still much to learn. This certainly seems to be the case with regard to injuries of the anterior cruciate ligament (ACL). ACL injuries are among the most common injuries sustained in the United States. Over 100,000 ACL reconstructions were performed in the United States in 2006, and the annual rate has continued to increase over time. Although some patients have achieved good results after nonoperative treatment, a survey of the American Orthopaedic Society for Sports Medicine showed that the majority of respondents used nonoperative treatment for fewer than 25% of their patients with ACL injuries.
Noyes et al.1 described the so-called “rule of thirds.” According to this rule, one-third of patients with an ACL injury will compensate well with nonoperative treatment (copers), one-third will avoid symptoms of instability by modifying activities (adapters), and one-third will require operative reconstruction (noncopers). Unfortunately, there does not seem to be any way to predict which group an individual patient will fall into. Thus, there is still substantial ambiguity in determining which patients are most likely to benefit from early intervention with ACL reconstruction following injury.
In this month’s issue of JBJS Reviews, Secrist et al. used the literature to perform a comparison of operative and nonoperative treatment of ACL injuries. They noted that only 3 randomized controlled trials have compared operative and nonoperative treatment of ACL injuries and that 2 of those studies involved the use of ACL suturing as opposed to more modern forms of reconstruction. The third study involved only 32 patients. All studies had substantial methodological limitations. The authors concluded that there have been no Level-I studies comparing ACL reconstruction with nonoperative treatment.
In their review article, Secrist et al. attempted to define and evaluate the available data on the natural history of nonoperatively treated ACL injuries and to determine how the functional outcomes and injury risks associated with nonoperative treatment compared with those associated with reconstruction. Moreover, they sought to define prognostic factors and rehabilitation protocols associated with successful operative outcomes. Finally, they compared the outcomes following early versus delayed ACL reconstruction.
However, by the end of the article, one gets the feeling that the authors have “come full circle.” The authors summarize their findings by saying that some patients can cope with a torn ACL and return to preinjury activity levels, including participation in pivoting sports. On the other hand, patients who have an ACL injury along with a concomitant meniscal injury are at increased risk for osteoarthritis, and it is unclear what effect reconstruction of an isolated ACL has on future osteoarthritis risk in ACL-deficient patients who are identified as “copers.”
I suspect that we will continue to see articles on this topic for many years to come. In light of the “rule of thirds” and the additional impact of meniscal injury, the allocation of a particular patient to operative or nonoperative treatment remains unclear.
Thomas A. Einhorn, MD
Editor, JBJS Reviews
- Noyes FR, Matthews DS, Mooar PA, Grood ES. The symptomatic anterior cruciate-deficient knee. Part II: the results of rehabilitation, activity modification, and counseling on functional disability. J Bone Joint Surg Am. 1983 Feb;65(2):163-74 Medline.