Headline
The study found that neither the Thessaly Test alone or in combination with other physical tests could be reliably used by primary care clinicians as an alternative, or surrogate, for magnetic resonance imaging (MRI) scanning to diagnose meniscal tears in the knee. In addition, data generated by this study suggests that MRI diagnosis of meniscal tears in comparison with arthroscopic diagnosis was less accurate than is commonly reported in literature.
Abstract
Background:
Reliable non-invasive diagnosis of meniscal tears is difficult. Magnetic resonance imaging (MRI) is often used but is expensive and incidental findings are problematic. There are a number of physical examination tests for the diagnosis of meniscal tears that are simple, cheap and non-invasive.
Objectives:
To determine the diagnostic accuracy of the Thessaly test and to determine if the Thessaly test (alone or in combination with other physical tests) can obviate the need for further investigation by MRI or arthroscopy for patients with a suspected meniscal tear.
Design:
Single-centre prospective diagnostic accuracy study.
Setting:
Although the study was performed in a secondary care setting, it was designed to replicate the results that would have been achieved in a primary care setting.
Participants:
Two cohorts of patients were recruited: patients with knee pathology (n = 292) and a control cohort with no knee pathology (n = 75).
Main outcome measures:
Sensitivity, specificity and diagnostic accuracy of the Thessaly test in determining the presence of meniscal tears.
Methods:
Participants were assessed by both a primary care clinician and a musculoskeletal clinician. Both clinicians performed the Thessaly test, McMurray’s test, Apley’s test, joint line tenderness test and took a standardised clinical history from the patient.
Results:
The Thessaly test had a sensitivity of 0.66, a specificity of 0.39 and a diagnostic accuracy of 54% when utilised by primary care clinicians. This compared with a sensitivity of 0.62, a specificity of 0.55 and diagnostic accuracy of 59% when used by musculoskeletal clinicians. The diagnostics accuracy of the other tests when used by primary care clinicians was 54% for McMurray’s test, 53% for Apley’s test, 54% for the joint line tenderness test and 55% for clinical history. For primary care clinicians, age and past history of osteoarthritis were both significant predictors of MRI diagnosis of meniscal tears. For musculoskeletal clinicians age and a positive diagnosis of meniscal tears on clinical history taking were significant predictors of MRI diagnosis. No physical tests were significant predictors of MRI diagnosis in our multivariate models. The specificity of MRI diagnosis was tested in subgroup of patients who went on to have a knee arthroscopy and was found to be low [0.53 (95% confidence interval 0.28 to 0.77)], although the sensitivity was 1.0.
Conclusions:
The Thessaly test was no better at diagnosing meniscal tears than other established physical tests. The sensitivity, specificity and diagnostic accuracy of all physical tests was too low to be of routine clinical value as an alternative to MRI. Caution needs to be exercised in the indiscriminate use of MRI scanning in the identification of meniscal tears in the diagnosis of the painful knee, due to the low specificity seen in the presence of concomitant knee pathology. Further research is required to determine the true diagnostic accuracy and cost-effectiveness of MRI for the detection of meniscal tears.
Trial registration:
Current Controlled Trial ISRCTN43527822.
Funding:
The National Institute for Health Research Health Technology Assessment programme.
Article history
The research reported in this issue of the journal was funded by the HTA programme as project number 09/163/02. The contractual start date was in September 2012. The draft report began editorial review in July 2014 and was accepted for publication in March 2015. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The HTA editors and publisher have tried to ensure the accuracy of the authors’ report and would like to thank the reviewers for their constructive comments on the draft document. However, they do not accept liability for damages or losses arising from material published in this report.
Declared competing interests of authors
John Norrie is a member of the National Institute for Health Research Health Technology Assessment (HTA) and Efficacy and Mechanism Evaluation Editorial Board and HTA Commissioning Board.
