Emergency Department Management of Knee Pain

Table of Contents

 

About This Issue

Knee pain presentations to the ED have a vast differential that includes soft-tissue and fractures injuries, degenerative diseases, and overuse syndromes, as well as inflammatory and infectious causes. Determining the likely cause of a patient’s knee pain will help emergency clinicians lead patients to definitive management and improved quality of life. In this issue, you will learn:

How to use anatomical location of symptoms and clinical clues to help narrow the differential

How to choose special tests for knee conditions based on the suspected location of injury

How to use the Ottawa knee rule to determine when x-rays will be needed

Knee ultrasound: the evidence on its use for diagnosis of pain as well as for arthrocentesis guidance

What the diagnostic features of synovial fluid are and what they reveal about joint effusions

The evidence on treatments for knee pain: physical therapy, medication, joint injections, taping, orthotics, immobilizers, and nerve blocks

1. About This Issue
2. Abstract
3. Case Presentations
4. Introduction
5. Critical Appraisal of the Literature
6. Etiology and Pathophysiology
7. Differential Diagnosis
8. Prehospital Care
9. Emergency Department Evaluation
   1. History
   2. Physical Examination
      1. Inspection
      2. Palpation
      3. Range of Motion
      4. Strength
      5. Special Tests
      6. Neurovascular Examination
10. Diagnostic Studies
    1. Imaging
       1. X-Ray
       2. Ultrasound
       3. Procedure for Performing Ultrasound of the Knee
       4. Computed Tomography and Magnetic Resonance Imaging
    2. Laboratory Testing
       1. Arthrocentesis
          1. Procedures for Palpation-Guided Arthrocentesis and Ultrasound-Guided Arthrocentesis
          2. Palpation-Guided Arthrocentesis
          3. Ultrasound-Guided Arthrocentesis
11. Treatment
    1. Atraumatic Knee Pain
       1. Weight Loss, Exercise, and Physical Therapy
       2. Orthotics and Taping
       3. Tai Chi
       4. Medication Therapies
       5. Nerve Block Therapy
    2. Traumatic Knee Pain
    3. Inflammatory Causes
12. Special Populations
    1. Pediatric Patients
    2. Patients With Knee Prosthesis
13. Controversies and Cutting Edge
    1. Knee Immobilizers
    2. Joint Injections
       1. Corticosteroid Injections
       2. Ketorolac Injections
    3. Physical Therapy
14. Disposition
15. Summary
16. Time- and Cost-Effective Strategies
17. 5 Things That Will Change Your Practice
18. Risk Management Pitfalls for Emergency Department Patients With Knee Pain
19. Case Conclusions
20. Clinical Pathway for Emergency Department Management of Atraumatic Knee Pain
21. Tables and Figures
22. References

Abstract

Knee pain is a common presenting complaint in the emergency department, and although the major etiologies are overuse and degenerative, inflammatory and infectious causes must be ruled out. This issue reviews the potential causes of knee pain from the history and physical examination, symptom location-based differential, clinical clues, and special testing strategies. Evidence on the uses of x-ray and ultrasound for diagnostic imaging is reviewed. For suspected infectious causes, procedures for palpation-guided and ultrasound-guided arthrocentesis are outlined. Treatment strategies are summarized, with evidence on the effectiveness of weight loss, physical therapy, orthotics, medication therapies, joint injections, and nerve blocks considered.

Case Presentations

A 19-year-old woman presents with knee pain that she says becomes worse when she is running…

• Her vital signs are: temperature, 37°C; heart rate, 72 beats/min; blood pressure, 114/68 mm Hg; and respiratory rate, 14 breaths/min. You note that she has a low body mass index and a history of amenorrhea.
• On examination, she has no joint effusion, but her knee is quite tender on the medial femoral condyle.
• She has been waiting some time for radiographic studies, and you wonder: does she really need that knee x-ray?

A 70-year-old woman presents with knee pain that she says has been present for several months…

• She says there has been no trauma, and the pain has gotten progressively worse with ambulation.
• Her vital signs are: temperature, 36.8°C; heart rate, 88 beats/min; blood pressure, 136/80 mm Hg; and respiratory rate, 12 breaths/min.
• On examination, she is tender along both the medial and lateral joint lines, with a trace effusion. You note that both of her knees seem to have overt degenerative changes.
• The physician assistant with you at bedside asks whether a knee immobilizer would be appropriate…

A 32-year-old man is brought in by EMS with fever and knee pain…

• His vital signs are: temperature, 39°C; heart rate, 108 beats/min; blood pressure, 120/82 mm Hg; and respiratory rate, 16 breaths/min.
• When you ask him about risk factors, he says that he is an IV drug user.
• Although the patient is currently hemodynamically stable, he looks very uncomfortable. There is effusion in his right knee, it is warm, and he has extreme pain with any range of motion.
• You consider the high likelihood that this patient has a septic knee joint, and wonder: is bedside ultrasound best-practice for aspirating a septic joint? What are the current laboratory cutoff levels for making a diagnosis of septic arthritis?

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Clinical Pathway for Emergency Department Management of Atraumatic Knee Pain

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Tables and Figures

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Key References

Following are the most informative references cited in this paper, as determined by the authors.

5. * Kandemirli GC, Basaran M, Kandemirli S, et al. Assessment of knee osteoarthritis by ultrasonography and its association with knee pain. J Back Musculoskelet Rehabil. 2020;33(4):711-717. (Cross-sectional; 99 patients) DOI: 10.3233/BMR-191504

11. * Helito CP, Teixeira PR, Oliveira PR, et al. Septic arthritis of the knee: clinical and laboratory comparison of groups with different etiologies. Clinics (Sao Paulo). 2016;71(12):715-719. (Retrospective; 105 patients) DOI: 10.6061/clinics/2016(12)07

19. * Kastelein M, Luijsterburg PA, Wagemakers HP, et al. Diagnostic value of history taking and physical examination to assess effusion of the knee in traumatic knee patients in general practice. Arch Phys Med Rehabil. 2009;90(1):82-86. (Prospective, observational cohort studies; 134 patients) DOI: 10.1016/j.apmr.2008.06.027

27. * Sims JI, Chau MT, Davies JR. Diagnostic accuracy of the Ottawa knee rule in adult acute knee injuries: a systematic review and meta-analysis. Eur Radiol. 2020;30(8):4438-4446. (Systematic review and meta-analysis; 8 studies, 7385 patients) DOI: 10.1007/s00330-020-06804-x

29. * Wu TS, Roque PJ, Green J, et al. Bedside ultrasound evaluation of tendon injuries. Am J Emerg Med. 2012;30(8):1617-1621. (Prospective study; 34 patients) DOI: 10.1016/j.ajem.2011.11.004

43. * Sibbitt WL, Jr., Kettwich LG, Band PA, et al. Does ultrasound guidance improve the outcomes of arthrocentesis and corticosteroid injection of the knee? Scand J Rheumatol. 2012;41(1):66-72. (Randomized controlled trial; 64 knees) DOI: 10.3109/03009742.2011.599071

53. * Underwood M, Ashby D, Carnes D, et al. Topical or oral ibuprofen for chronic knee pain in older people. The TOIB study. Health Technol Assess. 2008;12(22):155. (Randomized controlled trial; 585 patients in 26 UK general practices) DOI: 10.3310/hta12220

59. * Toupin April K, Bisaillon J, Welch V, et al. Tramadol for osteoarthritis. Cochrane Database Syst Rev. 2019;5(5):CD005522. (Cochrane review; 22 trials, 6496 patients) DOI: 10.1002/14651858.CD005522.pub3

70. * Chughtai M, Elmallah RD, Mistry JB, et al. Nonpharmacologic pain management and muscle strengthening following total knee arthroplasty. J Knee Surg. 2016;29(3):194-200. (Review) DOI: 10.1055/s-0035-1569147

76. * McAlindon TE, LaValley MP, Harvey WF, et al. Effect of intra-articular triamcinolone vs saline on knee cartilage volume and pain in patients with knee osteoarthritis: a randomized clinical trial. JAMA. 2017;317(19):1967-1975. (Randomized placebo-controlled double-blind trial; 140 patients) DOI: 10.1001/jama.2017.5283

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Keywords: arthritis, osteoarthritis, ligament, tendon, patella, meniscus, septic, prosthesis, effusion, dislocation, quadriceps, ROM, Ottawa, ultrasound, arthrocentesis, immobilizer