Article Text

No evidence found that a femoral nerve block in cases of femoral shaft fractures can delay the diagnosis of compartment syndrome of the thigh
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1. George Karagiannis, Medical student,
2. Richard Hardern, Consultant
1. Department of Emergency Medicine, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK; s.carley1btinternet.com

## Abstract

A short cut review was carried out to establish whether a femoral nerve block may mask the signs and symptoms of thigh compartment syndrome. No relevant papers were found using the reported search. There is no evidence to associate a femoral nerve block with a delayed or missed diagnosis of compartment syndrome.

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Report by George Karagiannis, Medical studentChecked by Richard Hardern, Consultant

### Three part question

In [adults with suspected femoral shaft fracture] is there an association between [pain relief with femoral nerve block] and [delayed or missed diagnosis of compartment syndrome]?

### Clinical scenario

A 30 year old man is brought into accident and emergency following a bicycle accident. He is complaining of agonising pain in his right thigh. On examination his thigh is very swollen and any attempt to move it is extremely painful. You suspect a femoral shaft fracture and want to administer some strong analgesia and a splint and send him for an x ray. The orthopaedic registrar complains that a femoral block could potentially mask the symptoms of a compartment syndrome. You are wondering if there is any evidence to support this.

### Search strategy

Medline(R) 1966 to July 2005 using the OVID interface: [{exp Nerve Block/or exp Anesthesia, Local/or exp Anesthetics, Local/or exp BUPIVACAINE/or exp LIDOCAINE/or exp PRILOCAINE/or (nerve$and block$).mp. or (an?esthe$and local).mp. or (an?esthe$ and block$).mp. or BUPIVACAIN$.mp. or (LIDOCAIN$or LIGNOCAIN$).mp. or PRILOCAIN$.mp. or (regional and an?esthe$).mp. or (regional and block$).mp. or (regional and analgesia).mp. or (local and analgesia).mp.} AND {exp Femoral Fractures/or (exp thigh/and exp fracture/) or (fem#r$ and fracture$).mp. or (thigh and fracture$).mp.} AND {exp Compartment Syndrome/or (compartment$and syndrome$).mp. or (volkmann$and contracture$).mp.}] LIMIT to human AND English. Embase 1980 to July 2005 using the OVID interface: [{exp Nerve Block/or exp Anesthesia, Local/or exp Anesthetics, Local/or exp BUPIVACAINE/or exp LIDOCAINE/or exp PRILOCAINE/or (nerve$and block$).mp. or (an?esthe$and local).mp. or (an?esthe$ and block$).mp. or BUPIVACAIN$.mp. or (LIDOCAIN$or LIGNOCAIN$).mp. or PRILOCAIN$.mp. or (regional and an?esthe$).mp. or (regional and block$).mp. or (regional and analgesia).mp. or (local and analgesia).mp.} AND {exp Femoral Fractures/or (exp thigh/and exp fracture/) or (fem#r$ and fracture$).mp. or (thigh and fracture$).mp.} AND {exp Compartment Syndrome/or exp Volkmann Contracture/or (compartment$and syndrome$).mp. or (volkmann$and contracture$).mp.}] LIMIT to human AND English. All EBM Reviews (Cochrane DSR, ACP Journal Club, DARE, and CCTR) using the OVID interface: [{((nerve$and block$) or (an?esthe$and local) or (an?esthe$ and block$) or BUPIVACAIN$ or (LIDOCAIN$or LIGNOCAIN$) or PRILOCAIN$or (regional and an?esthe$) or (regional and block$) or (regional and analgesia) or (local and analgesia)).mp.} AND {((fem#r$ and fracture$) or (thigh and fracture$)).mp.} AND {((compartment$and syndrome$) or (volkmann$and contracture$)).mp.}] LIMIT to human AND English.

### Search outcome

Altogether three papers were found in Medline, six in Embase and one in all EBM, of which none were relevant.

### Relevant paper(s)

No relevant papers were found.

### Comment(s)

No reliable evidence or any official guidance has been found to contraindicate the administration of a femoral block. In theory, pain disproportionate to the injury is thought to be the most important indicator of acute compartment syndrome in awake patients. However the diagnostic value of this sign is doubtful since the fracture as such can cause intolerable pain. Strong analgesia at this point will allow for a relatively painless application of a splint which in turn will provide adequate immobilisation of the limb. With the splint in place it is easier and less painful to transfer and position the patient in the x ray department. Plus it is thought to reduce haematoma formation.

## CLINICAL BOTTOM LINE

There is no evidence of an association between a femoral nerve block with a delayed or missed diagnosis of compartment syndrome.

## Acknowledgments

The authors would like to thank Mr Chris Phillips, Consultant, for his guidance in preparing this BET.

Report by George Karagiannis, Medical studentChecked by Richard Hardern, Consultant