• 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.