• Pavlov H, Saboeiro GR, Campbell SE, Dalinka MK, Daffner RH, DeSmet AA, El-Khoury GY, Kneeland JB, Manaster BJ, Morrison WB, Rubin DA, Schneider R, Steinbach LS, Weissman BN, Haralson RH III, Expert Panel on Musculoskeletal Imaging. Acute trauma to the knee. [online publication]. Reston (VA): American College of Radiology (ACR); 2005. 9 p. [97 references]

This is the current release of the guideline.

It updates a previous published version: ACR Appropriateness Criteria™ for acute trauma to the knee. Reston (VA): American College of Radiology (ACR); 2001. 8 p. (ACR appropriateness criteria). [92 references]

The appropriateness criteria are reviewed annually and updated by the panels as needed, depending on introduction of new and highly significant scientific evidence.

ACR Appropriateness Criteria®

Clinical Condition: Acute Trauma to the Knee

Variant 1: Patient any age (excluding infants)-–fall or twisted injury, no focal tenderness, no effusion; able to walk.

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 2: Patient, any age (excluding infants)-–fall or twisting injury, with one or more of following: focal tenderness, effusion, inability to bear weight. First study.

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 3: Injury to knee 2 days ago, mechanism unknown. Focal patellar tenderness, effusion, able to walk.

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 4: Significant trauma to knee from motor vehicle accident, suspect posterior knee dislocation.

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Clinical decision rules for evaluating the acutely injured knee have been studied by various investigators, who determined that their application can considerably reduce the number of radiographs ordered without missing a clinically significant fracture. Although different parameters and definitions were used for the various decision rules, there were sufficient similarities between the investigations to allow usable conclusions to be drawn.

In patients of any age except for infants, the clinical parameters used for not requiring a radiograph following knee trauma are as follows:

• Patient is able to walk without a limp
• Patient had a twisting injury and there is no effusion

The clinical parameters for ordering knee radiographs in this population following trauma are as follows:

• Joint effusion within 24 hours of direct blow or fall
• Palpable tenderness over fibular head or patella
• Inability to walk (four steps) or bear weight immediately or in the emergency room or within a week of the trauma
• Inability to flex knee to 90 degrees

It was determined that normal radiographs could be expected in the absence of immediate swelling, ecchymosis, deformity, increased warmth, or abrasion/laceration. It was further stated that a fracture could be excluded if the single lateral view of the knee was normal, eliminating the need for additional radiographic views. In general, these studies excluded patients with superficial skin injuries, gross deformity, a palpable mass, a penetrating injury, prosthetic hardware, altered consciousness (from alcohol and drug use), multiple injuries, decreased limp sensation, or a history indicating an elevated risk of fracture. They also excluded pregnant patients, those who were returning for reassessment, and patients with injury for more than seven days.

In addition to the clinically significant fractures, occult bony injuries may occur that are not evident on radiograph and are best diagnosed on MRI or triple-phase bone scan (TPBS). Newer MRI techniques are very sensitive and specific to these lesions. The TPBS is sensitive but cannot determine the exact anatomical injury.

Although lateral patellar dislocation may be reduced at the time of presentation in the emergency room, there is usually focal patellar tenderness on clinical exam. The injury is associated with a definite pattern of bony injuries on radiographs and on the MRI examination; a medial reticulum injury may also be evident. These patients typically do not require surgery. A complete knee dislocation, even if spontaneously reduced, constitutes a potential threat to the popliteal nerve or artery. MRA or Doppler should be performed to evaluate the artery. If MRA is performed, an MRI should also be performed to identify ligamentous injuries and associated pathology. Additionally, it has been reported that a bifurcate ligament injury equates to a knee dislocation in terms of severity of ligamentous injury and frequency of major arterial injuries.

Decision rules for the evaluation of soft-tissue injuries are being investigated and have not yet been published. Soft tissue injuries (meniscal injuries, chondral surface injuries, and ligamentous disruption) are best evaluated by MRI. In addition to MRI, SPECT has also been reported to be accurate for diagnosing meniscal injuries, while sonography has been shown to be diagnostic for acute anterior cruciate ligament (ACL) injuries in the presence of a hemarthrosis or for follow-up of ACL injuries.

As with ankle injuries, decision rules are applicable to patients with an acutely injured knee and can significantly decrease the use of radiographs without the likelihood of missing a clinically important fracture. More than 92% of radiographs for acute knee pain in the emergency rooms across the United States are negative for fractures. The knee exam in the emergency room exemplifies how many low-cost but high-volume tests contribute as much to the escalating health care costs as high-cost but low-volume procedures. A decrease in the inappropriate usage of radiographs could in theory result in a shorter waiting time in emergency rooms and radiograph departments, and also decrease costs for the health care system without loss of quality.

Abbreviations

• CT, computed tomography
• MRA, magnetic resonance angiography
• MRI, magnetic resonance imaging
• NUC, nuclear medicine
• SPECT, single photon emission computed tomography
• TPBI, triple-phase bone imaging
• US, ultrasound

Algorithms were not developed from criteria guidelines.

The recommendations are based on analysis of the current literature and expert panel consensus.

• Pavlov H, Saboeiro GR, Campbell SE, Dalinka MK, Daffner RH, DeSmet AA, El-Khoury GY, Kneeland JB, Manaster BJ, Morrison WB, Rubin DA, Schneider R, Steinbach LS, Weissman BN, Haralson RH III, Expert Panel on Musculoskeletal Imaging. Acute trauma to the knee. [online publication]. Reston (VA): American College of Radiology (ACR); 2005. 9 p. [97 references]

Not applicable: The guideline was not adapted from another source.

1998 (revised 2005)

American College of Radiology - Medical Specialty Society

The American College of Radiology (ACR) provided the funding and the resources for these ACR Appropriateness Criteria®.

Committee on Appropriateness Criteria, Expert Panel on Musculoskeletal Imaging

Panel Members: Helene Pavlov, MD (Principal Author); Gregory R. Saboeiro, MD; Scot E. Campbell, MD; Murray K. Dalinka, MD (Panel Chair); Richard H. Daffner, MD; Arthur A. De Smet, MD; George Y. El-Khoury, MD; John B. Kneeland, MD; B.J. Manaster, MD, PhD; William B. Morrison, MD; David A. Rubin, MD; Robert Schneider, MD; Lynne S. Steinbach, MD; Barbara N. Weissman, MD; Robert H. Haralson III, MD

Not stated

This is the current release of the guideline.

It updates a previous published version: ACR Appropriateness Criteria™ for acute trauma to the knee. Reston (VA): American College of Radiology (ACR); 2001. 8 p. (ACR appropriateness criteria). [92 references]

The appropriateness criteria are reviewed annually and updated by the panels as needed, depending on introduction of new and highly significant scientific evidence.

None available

This summary was completed by ECRI on May 6, 2001. The information was verified by the guideline developer as of June 29, 2001. This summary was updated by ECRI on July 31, 2002. The updated information was verified by the guideline developer on October 1, 2002. This summary was updated by ECRI on February 6, 2006.