Magnetic resonance imaging (MRI) is a proven imaging modality for the detection, evaluation, assessment, staging, and follow-up of disorders of the knee. Properly performed and interpreted, MRI not only contributes to diagnosis but also serves as an important guide to treatment planning and prognostication. However, it should be performed only for a valid medical reason and after careful consideration of alternative imaging modalities. Radiographs will be the first imaging test performed for most suspected bone and soft tissue abnormalities of the knee and will often suffice to diagnose or exclude an abnormality or direct further imaging work-up.
While MRI is a sensitive, noninvasive diagnostic test for detecting anatomic abnormalities of the knee, its findings may be misleading if not closely correlated with radiographs, clinical history, physical examination, and physiologic tests. Adherence to the following guidelines will enhance the probability of detecting such abnormalities.

  1. Primary indications for MRI of the knee include, but are not limited to, diagnosis, exclusion, and grading of suspected:
    1. Meniscal disorders: nondisplaced and displaced tears, discoid menisci, meniscal cysts; complications of meniscal surgery†
    2. Ligament abnormalities: cruciate and collateral sprains and tears; complications following ligament repair or reconstruction†
    3. Extensor mechanism abnormalities: quadriceps and patellar tendon degeneration, partial, and complete tears; patellar fractures and sleeve avulsions; and retinacular sprains and tears
    4. Osteochondral abnormalities: osteochondral fractures, osteochondritis dissecans, treated osteochondral defects†
    5. Articular cartilage abnormalities: degenerative chondrosis, chondromalacia, chondral fissures, fractures, flaps, and separations; complications following chondral surgery†
    6. Loose bodies and impinging structures: Hoffa’s syndrome, symptomatic plicae†
    7. Synovial-based disorders: synovitis, bursitis, and popliteal cysts*
    8. Marrow abnormalities: osteonecrosis, marrow edema syndromes, stress fractures, and radiographically occult fractures*
    9. Muscle and tendon disorders: strains, partial and complete tears, tendinitis, tendinopathy, inflammation, and ischemia
    10. Iliotibial band friction syndrome
    11. Neoplasms of bone, joint, or soft tissue*
    12. Infections of bone, joint, or soft tissue*
    13. Congenital and developmental conditions: Blount disease, dysplasia, normal variants*
    14. Vascular conditions: entrapment, aneurysm, stenosis, occlusion, cystic change*
    15. Neurologic conditions: entrapment, compression, denervation, and peripheral neuritis*
  1. MRI of the knee may be indicated to further clarify and stage conditions diagnosed clinically and/or suggested by other imaging modalities, including, but not limited to:
    1. Arthritides: inflammatory, infectious, neuropathic, degenerative, crystal-induced, post-traumatic*
    2. Primary and secondary bone and soft tissue tumors*
    3. Fractures and dislocations
  1. MRI of the knee may be useful to evaluate specific clinical scenarios, including, but not limited to:
    1. Prolonged, refractory, or unexplained knee pain
    2. Acute knee trauma
    3. Mechanical knee symptoms: catching, locking, snapping, crepitus†
    4. Tibiofemoral and/or patellofemoral instability: chronic, recurrent, subacute, acute dislocation and subluxation†
    5. Tibiofemoral malalignment and/or patellofemoral malalignment or maltracking
    6. Limited or painful range of motion
    7. Swelling, enlargement, mass, or atrophy*
    8. Patients for whom diagnostic or therapeutic arthroscopy is planned†
    9. Patients with recurrent, residual, or new symptoms following knee surgery†
    10. Patients with selected complications following knee arthroplasty



American College of Radiology (ACR), Society of Skeletal Radiology (SSR). ACR-SSR practice guideline for the performance and interpretation of magnetic resonance imaging (MRI) of the knee. [online publication]. Reston (VA): American College of Radiology (ACR); 2010. 11 p.  [141 references]