Diagnosis

During the physical exam, your doctor will check your knee for swelling and tenderness — comparing your injured knee to your uninjured knee. He or she also may move your knee into a variety of positions to assess range of motion and overall function of the joint.

Often the diagnosis can be made on the basis of the physical exam alone, but you may need tests to rule out other causes and to determine the severity of the injury. These tests may include:

  • X-rays. X-rays may be needed to rule out a bone fracture. However, X-rays can't visualize soft tissues, such as ligaments and tendons.
  • Magnetic resonance imaging (MRI). An MRI uses radio waves and a strong magnetic field to create images of both hard and soft tissues in your body. An MRI can show the extent of an ACL injury and signs of damage to other tissues in the knee.
  • Ultrasound. Using sound waves to visualize internal structures, ultrasound may be used to check for injuries in the ligaments, tendons and muscles of the knee.
Dec. 22, 2015
References
  1. Friedberg RP. Anterior cruciate ligament injury. http://www.uptodate.com. Accessed Oct. 10, 2015.
  2. Frontera WR. Anterior cruciate ligament tear. In: Essentials of Physical Medicine and Rehabilitation: Musculoskeletal Disorders, Pain, and Rehabilitation. 3rd ed. Philadelphia, Pa.: Saunders Elsevier; 2015. http://www.clinicalkey.com. Accessed Oct. 22, 2015.
  3. Anterior cruciate ligament (ACL) injuries. American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=a00549. Accessed Oct. 15, 2015.
  4. ACL injury: Does it require surgery? American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00297. Accessed Oct. 15, 2015.
  5. Shea KG, et al. The American Academy of Orthopaedic Surgeons evidence-based guideline on management of anterior cruciate ligament injuries. Journal of Bone and Joint Surgery. 2015;97:672.
  6. Knee arthroscopy exercise guide. American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00300. Accessed Oct. 15. 2015.
  7. Stuart MJ (expert opinion). Mayo Clinic, Rochester, Minn. Oct. 28, 2015.
  8. Peterson JR, et al. Anterior cruciate ligament injury: Mechanisms of injury and strategies for injury prevention. Physical Medicine and Rehabilitation Clinics of North America. 2014;25:813.
  9. ACL injuries in young athletes. Stop Sport Injuries. American Orthopaedic Society for Sports Medicine. http://www.stopsportsinjuries.org/acl-injury-prevention.aspx. Accessed Nov. 24, 2015.