The DAMASK trial protocol: a pragmatic randomised trial to evaluate whether GPs should have direct access to MRI for patients with suspected internal derangement of the knee.
BACKGROUND
Though new technologies like Magnetic Resonance Imaging (MRI) may be accurate, they often diffuse into practice before thorough assessment of their value in diagnosis and management, and of their effects on patient outcome and costs. MRI of the knee is a common investigation despite concern that it is not always appropriate. There is wide variation in general practitioners (GPs) access to, and use of MRI, and in the associated costs. The objective of this study was to resolve uncertainty whether GPs should refer patients with suspected internal derangement of the knee for MRI or to an orthopaedic specialist in secondary care.


METHODS
The design consisted of a pragmatic multi-centre randomised trial with two parallel groups and concomitant economic evaluation. Patients presenting in general practice with suspected internal derangement of the knee and for whom their GP was considering referral to an orthopaedic specialist in secondary care were eligible for inclusion. Within practices, GPs or practice nurses randomised eligible and consenting participants to the local radiology department for an MRI examination, or for consultation with an orthopaedic specialist. To ensure that the waiting time from GP consultation to orthopaedic appointment was similar for both trial arms, GPs made a provisional referral to orthopaedics when requesting the MRI examination. Thus we evaluated the more appropriate sequence of events independent of variations in waiting times. Follow up of participants was by postal questionnaires at six, twelve and 24 months after randomisation. This was to ensure that the evaluation covered all events up to and including arthroscopy.


CONCLUSIONS
The DAMASK trial should make a major contribution to the development of evidence-based partnerships between primary and secondary care professionals and inform the debate when MRI should enter the diagnostic pathway.
Brealey
Stephen D
SD
Department of Health Sciences, York Trials Unit, Seebohm Rowntree Building, University of York, Heslington, York YO10 5DD, UK. sb143@york.ac.uk
Atwell
Christine
C
Bryan
Stirling
S
Coulton
Simon
S
Cox
Helen
H
Cross
Ben
B
Fylan
Fiona
F
Garratt
Andrew
A
Gilbert
Fiona J
FJ
Gillan
Maureen G C
MG
Hendry
Maggie
M
Hood
Kerenza
K
Houston
Helen
H
King
David
D
Morton
Veronica
V
Orchard
Jo
J
Robling
Michael
M
Russell
Ian T
IT
Torgerson
David
D
Wadsworth
Valerie
V
Wilkinson
Clare
C
D000293:Adolescent; D000328:Adult; D002983:Clinical Competence; D002985:Clinical Protocols; D016001:Confidence Intervals; D005194:Family Practice / Q000193:education / Q000592:standards*; D005260:Female; D006297:Health Services Accessibility / Q000458:organization & administration*; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009985:Orthopedics; D026761:Physical Therapy Specialty; D016059:Range of Motion, Articular; D012017:Referral and Consultation / Q000458:organization & administration*; D012107:Research Design; D012307:Risk Factors; D006113:United Kingdom