History and Physical
Strong evidence supports that the practitioner should obtain a relevant history and perform a musculoskeletal exam of the lower extremities, because these are effective diagnostic tools for ACL injury.

Rationale
There were six high-strength and four moderate-strength studies evaluating history and physical examination as diagnostic tools for ACL injury. 8, 23, 32, 55, 58, 60, 87, 91, 104, 105 A relevant history is important for diagnosing ACL injuries and concomitant pathology and should include at a minimum the mechanism of injury, history of hearing/feeling a popping sensation, ability to bear weight, ability to return to play, history of mechanical symptoms of locking or catching, localization of pain if possible, and any history of prior knee injuries. 55, 60, 91 History of hearing/feeling a popping sensation and associated swelling is important in predicting an ACL injury.87

Appropriate physical exam is important in diagnosing ACL injuries and concomitant pathology and should also be performed including at a minimum: a neurovascular exam with documentation of both distal perfusion and tibial/peroneal nerve function, assessment for joint line tenderness or obvious step off/deformity, evaluation for an effusion, assessment of varus and valgus laxity at 0 and 30 degrees of extension, evaluation of anterior-posterior and rotational laxity. 8, 32, 58, 104, 105 Lachman’s test should be performed and has been shown to be sensitive for ACL injury.23

Benefits of Implementation
A thorough history and physical exam will assist the practitioner in prompt and accurate diagnosis of ACL injuries and concomitant pathology.

Possible Harms of Implementation
There are no known harms associated with appropriate implementation of this recommendation.

Future Research
Future research could help confirm the most useful history and physical exam findings for the diagnosis of ACL injury and concomitant pathology.