Figure 1: Normal AP knee x-ray. Case courtesy of Dr Andrew Dixon, Radiopaedia.org, annotations by Stephen Villa MD.
Have you ever been working a shift at 3am and wondered, “Am I missing something? I’ll just splint and instruct the patient to follow up with their PCP in 1 week.” This is a reasonable approach, especially if you’re concerned there could be a fracture. But we can do better. Enter the “Can’t Miss” series: a series organized by body part that will help identify injuries that ideally should not be missed. This list is not meant to be a comprehensive review of each body part, but rather to highlight and improve your sensitivity for these potentially catastrophic injuries. Now: the knee.
- 6 million ED visits for knee injuries between 1999 and 2008 .
- Most commonly injured joint of adolescent athletes .
Normal x-ray? Check out EMDocs’wonderful review of occult knee injuries. EMCases has a good review of occult knee injuries as well.
Want a basic approach to traumatic knee imaging? Check out EMRad’s approach to the traumatic knee x-ray.
- Gage, BE et al. Epidemiology of 6.6 million knee injuries presenting to United States emergency departments from 1999 through 2008. Acad Emerg Med. Volume 19. Issue 4. April 2012. PMID 22506941
- Glaspy, J et al. Chapter 271. Knee Injuries. In: Tintinalli’s Emergency Medicine. A Comprehensive Guide, 8th edition. New York: McGraw-Hill Education, 2016.
- Knutson, T. et al. Evaluation and management of traumatic knee injuries in the emergency department. Emerg Med Clin North Am. Volume 33. Issue 2. May 2015. PMID 25892726
- Gwinner, C. Current concept Reviews: Fractures of the patella. GMS Interdiscip Plast Reconstr Surg DGPW. Volume 18. Issue 5. Jan. 2016 PMID 26816667
- Gray, S. et al. Acute knee trauma: how many plain film views are necessary for the initial examination. Skeletal Radiol. Volume 5. May 1997. PMID 9194231
- Gamulin, A, et al. Clinical and radiographic predictors of acute compartment syndrome in the treatment of tibial plateau fractures: a retrospective cohort study. BMC Musculoskeletal Disorders. Volume 18. Issue 1. July 2017. PMID 28720096
- Markeson, CD et al. Arcuate Sign in posterolateral corner injury of the knee. J Emerg Med. Vol 19. Jan 2020.PMID: 32001118
- Strub, W. The Arcuate sign. Radiology. Volume 244. No. 2. August 2007. PMID 17641383
- Nannaparaju, M. Posterolateral corner injuries: Epidemiology, anatomy, biomechanics and diagnosis. Injury. Volume 49. Issue 6. June 2018. PMID 29254623