Effectiveness of GP access to magnetic resonance imaging of the knee: a randomised trial

DAMASK (Direct Access to Magnetic Resonance Imaging: Assessment for Suspect Knees) Trial Team, Stephen Derek Brealey, Helen Cox, Veronica Mary Morton, David John Torgerson

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Background GPs commonly see patients with knee problems. Magnetic resonance imaging (MRI) of the knee is an accurate diagnostic test for meniscus and ligament injuries of the knee, but there is uncertainty about the appropriate use of MRI and when it should enter the diagnostic pathway for patients with these problems.

Aim To assess the effectiveness of GP referral to early MRI and a provisional orthopaedic appointment, compared with referral to an orthopaedic specialist without prior MRI for patients with continuing knee problems.

Design of study Pragmatic multicentre randomised trial with two parallel groups.

Setting A total of 553 patients consulting their GP about a continuing knee problem were recruited from 163 general practices at 11 sites across the UK.

Method Patients were randomised to MRI within 12 weeks of GP referral including a provisional orthopaedic appointment, or orthopaedic appointment without prior MRI within a maximum of 9 months from GP referral. The primary outcome measures were the Short Form 36-item (SF-36) physical functioning scale and the Knee Quality of Life 26-item Questionnaire (KQoL-26) at 6, 12, and 24 months.

Results Patients randomised to MRI improved mean SF-36 physical functioning scores by 2.81 (95% confidence interval [CI] = -0.26 to 5.89) more than those referred to orthopaedics (P = 0.072). Patients randomised to MRI improved mean KQoL-26 physical functioning scores by 3.65 (95% Cl = 1.03 to 6.28) more than controls (P = 0.007). There were no other significant differences.

Conclusion GP access to MRI yielded small, but statistically significant, benefits in patients' knee-related quality of life but non-significant improvements in physical functioning.

Original languageEnglish
Pages (from-to)767-774
Number of pages8
JournalBritish Journal of General Practice
Issue number556
Publication statusPublished - Nov 2008


  • family practice
  • knee injuries
  • magnetic resonance imaging
  • randomised controlled trial
  • SF-36
  • MRI

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