Title : MRI before x-ray? The limited impact of pre-referral MRI-detected meniscal pathology on orthopaedic management
Abstract:
Introduction: Many patients with knee pain are referred to orthopaedic clinic after pre-referral MRI demonstrates meniscal pathology. In older patients, MRI frequently identifies degenerative or incidental meniscal abnormalities which may not be the primary driver of symptoms. This can create expectation of arthroscopy despite management often being determined by clinical assessment and radiographic osteoarthritis.
Aim: To evaluate whether pre-referral MRI-detected meniscal pathology alters subsequent orthopaedic management, and to assess the proportion of patients ultimately managed conservatively, via arthroscopy pathway, or via arthroplasty pathway.
Limitations of MRI:
•Non-weight-bearing imaging
•Relatively expensive compared with plain radiographs
•Frequently demonstrates incidental degenerative findings
•Can delay pathway progression while awaiting imaging/reporting
•May create unrealistic expectations of arthroscopy
•Is often not the deciding factor for operative management
Standards / Clinical Context:
• Weight-bearing knee radiographs should usually precede MRI in older patients with chronic atraumatic knee pain
• MRI should be used selectively, for example in true mechanical locking, acute trauma, suspected ligament injury, or diagnostic uncertainty
• Clinical assessment and plain radiographs often guide management more than MRI-reported degenerative meniscal change
Methods: Retrospective audit of 100 consecutive clinic patients referred following pre-referral MRI knee imaging. Data collected included age, MRI findings, presence or absence of previous/recent radiographs, and final clinic outcome. Patients were categorised into conservative/non-operative pathway, arthroscopy pathway, or arthroplasty pathway.
Results: Overall management outcome (n = 100)
• Conservative / non-operative / discharged: 82%
• Arthroscopy pathway: 8%
• Arthroplasty pathway (TKR / UKR): 7%
• Missing / unclear outcome: 3%
• 79/100 patients had MRI-reported meniscal pathology
• 37 patients were aged >60 with MRI-reported meniscal pathology
• In patients aged >60 with MRI-reported meniscal pathology and significant radiographic osteoarthritis (n = 11), 0 patients proceeded to arthroscopy
• 22% of patients had undergone MRI without previous or recent X-ray imaging recorded
• MRI changed management in only 9% overall, and in 0/11 of the key older OA subgroup
Discussion and Conclusion: This audit demonstrates that pre-referral MRI-detected meniscal pathology rarely leads to arthroscopic intervention. The majority of patients were managed conservatively or discharged, and a smaller proportion were directed towards arthroplasty pathways. In older patients with significant radiographic osteoarthritis, MRI did not alter management and no patients proceeded to arthroscopy. These findings suggest that MRI frequently identifies incidental or degenerative meniscal abnormalities without changing treatment decisions.
Recommendations:
•Encourage weight-bearing radiographs before MRI in older patients with chronic atraumatic knee pain
•Improve referral pathway education for GPs and referrers
•Reserve MRI for selected indications rather than routine use in degenerative knee pain
•Consider re-audit following pathway intervention
Estimated Cost Context: Knee MRI approximately £130 vs knee radiographs approximately £50–£60 (costs vary by provider and local tariff).
