Identifying individuals with an anterior cruciate ligament-deficient knee as copers and noncopers: a narrative literature review.

STUDY DESIGN Narrative literature review. OBJECTIVES First, to explore the differences and outcomes between individuals who have had anterior cruciate ligament (ACL) reconstruction and those who did not undergo surgical intervention, following a tear of the ACL. Second, to review the evidence related to the ability to identify individuals who may or may not need surgery after an ACL rupture. Finally, to describe the differences between copers and noncopers. BACKGROUND ACL rupture may result in increased tibiofemoral laxity and impaired neuromuscular function, which ultimately may lead to knee instability and dysfunction. Individuals who opt to choose surgery due to these changes may be defined as "noncopers." Conversely, those individuals who have an ACL-deficient knee without functional impairment and instability and successfully resume preinjury activity levels without surgical intervention may be defined as "copers." METHODS An electronic search was conducted up to April 2011, using medical subject headings and free-text words. The subject-specific search was based on the terms "anterior cruciate ligament reconstruction versus conservative treatment," "copers," "noncopers." RESULTS A similar percentage of copers and noncopers return to sporting activity. Three papers used an algorithm and screening examination involving individuals with ACL injuries. Evidence suggests that, as opposed to copers, noncopers have deficits in quadriceps strength, vastus lateralis atrophy, quadriceps activation deficits, altered knee movement patterns, reduced knee flexion moment, and greater quadriceps/hamstring cocontraction. CONCLUSION ACL screening examination showed preliminary evidence for detecting potential copers. Objective differences exist between copers and noncopers. Individuals with ACL injury should be informed of the possibility of good knee function following a nonoperative rehabilitation program.