• 
• 

Three Part Question

In [patients with suspected injuries to the ulnar collateral ligament of the thumb] does [investigation with ultrasound scanning] help to influence [the choice of treatment]?

Clinical Scenario

A patient attends the Emergency Department after a hyper abduction injury of his thumb. On examination there is laxity of his ulnar collateral ligament (UCL). You wonder whether conservative treatment is adequate or will the patient require surgery. Would ultrasonography be helpful in assessing UCL ruptures which are going to require surgical input?

Search Strategy

Search Strategy
OVID medline (R) 1950 to November week 3 2008 was searched. [(collateral ligaments OR ulnar collateral ligaments. Mp. OR rupture OR thumb. Mp.) AND (thumb/in.)AND (Diagnosis/ or diagnosis mp.) AND [ultrasound or ultrasonography ] LIMIT to human AND English. The Cochrane database was also searched which found no papers.

Search Outcome

A total of 10 papers were found. 4 of which were relevant and of sufficient quality to include in the paper.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Jones et al 2000, UK	60 patients with UCL injuries	Prospective cohort	USS Positive predictive value 94%. Sensitivity 83%, Specificity 75%.		Included patients > 3 weeks after injury. Difficult to pick up undisplaced lesions on USS.
Shinohara et al, 2006 Japan	14 patients with acute UCL tear	Retrospective cohort	USS and surgical findings	USS 100% specificity & sensitivity in intra aponeurosis injuries.	Small Numbers
O’Callaghan et al 1994 Switzerland	20 uninjured volunteers 48 patients with hyperabduction injuries 16 underwent surgery	Cohort		USS picked up 13/16 dislocations. None with negative scan had instability on review
Noszian et al 1995 Austria	69 patients with suspected UCL tear (<48 hrs post injury)			USS correct diagnosis 33/39 26/26 conservative treatment were stable on follow up

Comment(s)

Correct diagnosis of an ulnar collateral ligament injury is required to determine treatment. Clinical examination is often difficult. There is no consensus on the degree of laxity which signifies a complete ligament rupture. Non displaced ruptures can be treated conservatively for 6 weeks. Displaced ligament tears proximal to the aponeurosis are known as Stener lesions. A Stener lesion is unable to regain an anatomical position required for healing; therefore surgical intervention is indicated. Chronic instability of the thumb results if healing cannot occur. Treatment for suspected UCL rupture is controversial. Some advocate surgical exploration on all patients with a suspected rupture, whilst others advocate conservative treatment for 6 weeks. If instability remains at that time, then surgical repair is performed. However, surgical exploration is difficult when performed more than 3 weeks post injury. A quick, cheap, accessible imaging modality that could differentiate between lesions requiring surgery and those amenable to conservative treatment would be useful in the treatment and diagnosis of UCL tears. The papers above appear to show that ultrasound could aid in this differentiation. The benefit would be preventing every suspected lesion undergoing surgical exploration, and patients with definite displaced tears could have access to surgery sooner.

Clinical Bottom Line

Once the anatomy of the area is understood, USS appears to be a useful, cheap, adjunct to good clinical examination in acute ulnar collateral ligament injuries. It seems to be an accurate modality in diagnosising those lesions which will require surgical repair.

References

1. Jones, MH, England, SJ et al “The use of ultrasound in the diagnosis of injuries of the ulnar collateral ligament of the thumb” Journal of Hand Surgery (British and European) 2000;25B:1:29-32
2. Shinohara T, Horii, E et al “ Sonographic diagnosis of acute injuries of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb” Journal of Clinical Ultrasound 2007:35:73-77
3. O’Callaghan, BI, Kohut G, Hoogewood HM “Gamekeeper thumb: Identification of the Stener Lesion with US” Radiology 1994;192:477-480
4. Noszian IM, Dinkhauser LM et al “Ulnar collateral ligament: differentiation of displaced and nondisplaced tears with US Radiology 1995;194:61-63