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Three Part Question

In [young adults with acute knee haemarthrosis with no obvious fracture] is [early MRI better than arthroscopy] in [diagnosing intra-articular pathology]?

Clinical Scenario

A young man comes into the emergency department after sustaining a knee injury while playing football. Examination reveals a tense haemarthrosis; there is no evidence of fracture on x-ray. You wonder whether a MRI scan would be better than an arthroscopy to establish a diagnosis.

Search Strategy

Medline 1966-12/98 using the OVID interface.
[{exp magnetic resonance imaging OR magnetic resonance image$.mp OR magnetic resonance imaging.mp OR MRI.mp OR exp nuclear magnetic resonance OR NMR.mp} AND (exp knee OR exp knee injuries OR exp knee joint OR knee$.mp} AND {exp hemarthrosis OR hemarthrosis.mp OR haemarthrosis.mp})] LIMIT to human and english language.

Search Outcome

26 papers found of which 24 were irrelevant to the study question or of insufficient quality for inclusion.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Lundberg M et al 1996 Sweden	69 patients with unilateral knee haemarthrosis. MRI within days vs arthroscopy at a mean of 6 days	Prospective single blind diagnostic	ACL tears	sensitivity 86%, specificity 92%	Small sample size
			Medial meniscal tears	sensitivity 74%, specificity 66%
			Lateral meniscal tears	sensitivity 50%, specificity 84%
			Medial collateral ligament tears	sensitivity 56%, specificity 93%
Adalbert T et al 1997 Sweden	40 patients with acute traumatic intra-articular haemorrhage. MRI within 1 week vs arthroscopy within 1 week	Prospective diagnostic	Meniscal tears	sensitivity 76%, specificity 29% sensitivity 97%, specificity 50%	Small sample size

Comment(s)

Arthroscopy was used as a gold standard in both selected studies. MRI lacks both the sensitivity required for a SnOut and specificity required for a SpIn on this evidence. The evidence only applies to the conditions stated (haemarthrosis and investigation within 1 week) and different results might be found at different times.

Clinical Bottom Line

The evidence does not support early use of MRI scanning in acute knee haemarthrosis.

References

1. Lundberg M, Odensten M, Thuomas KA et al. The diagnostic validity of magnetic resonance imaging in acute knee injuries with hemarthrosis. A single-blinded evaluation in 69 patients using high-field MRI before arthroscopy. Int J Sports Medicine 1996;17(3):218-222.
2. Adalberth T, Roos H, Lauren M et al. Magnetic resonance imaging, scintigraphy, and arthroscopic evaluation of traumatic hemarthrosis of the knee. Am J Sports Med 1997;25(2):231-237.