Summary
- This paper is a brief introduction to the considerations which might affect the use of Magnetic Resonance Imaging (MRI) in investigation of the knee.
- Injuries to the knee are common in Australia and are generally managed by a combination of clinical examination, assisted by X-ray, arthrogram or arthroscopic diagnosis, and arthroscopic surgery if required. It is estimated that 60,000 arthroscopic procedures are performed each year in Australia, with the highest age-specific rate (three per 1,000) occurring in males in the 20-40 year age group.
- The technical accuracy of MRI investigation of disorders of the knee has been reviewed in relation to arthrography and arthroscopy. It has been reported that the use of surface coils has increased the overall diagnostic accuracy of MRI to 90-96% compared to arthroscopy. A current view is that the use of MRI might assist in the conduct of arthroscopic procedures, particularly when investigating tears of the posterior horn of the medial meniscus.
- Given that arthroscopic services are well established in Australia, the possible clinical role of MRI in management of disorders of the knee remains to be determined, MRI examinations may have a complementary role to arthroscopy by drawing attention to a suspicious region and thus assist in obtaining better outcomes from arthroscopic surgery.
- The relative cost of the use of MRI in the management of patients with knee problems remains uncertain. Overseas studies show that the use of MRI in selected patients may reduce the number of arthroscopies performed but may result in increased costs. There is ongoing debate on this matter between professional groups with orthopaedic specialists tending to favour the use of arthroscopy and radiologists proposing the use of MRI.
- Most existing MRI services in Australia are committed to examinations of the head and spine. The availability of resources to undertake examinations of the knee is an issue which would require further consideration. There would appear to be a need for a study to determine the effect of MRI on the management of disorders of the knee, having regard to the wide availability of arthroscopic services.