Sports Medicine: Just the Facts

CHAPTER 56 • MAGNETIC RESONANCE IMAGING: LOWER EXTREMITY 331

articular cartilage can be resolved (Waldschmidt et al,

1997) (Fig. 56-4).

• The high accuracy of MR imaging for diagnosing
  internal derangement of the knee has been demon-
  strated, with high reliability and accuracy in directing
  clinical treatment. A large series of 200 patients who
  had MR of the knee had arthroscopic correlation
  (Vincken et al, 2002). At the conclusion of the study,
  179 of the 200 patients were felt to have had a need for

arthroscopic treatment based on the MR findings (MR

sensitivity 93.2%, specificity 79.2%). Indications for

arthroscopic surgery diagnosed on MR imaging

included meniscal tears, cartilage lesions, cruciate lig-

ament injuries, collateral ligament injuries, and syn-

ovial disorders.

• Magnetic resonance imaging, particularly of the knee
  and shoulder, are becoming some of the most
  requested diagnostic imaging tests (Helms, 2002).


• MR imaging has a high sensitivity for diagnosing
  bone marrow edema. Causes of bone marrow edema
  pattern are varied and include trauma, avascular
  necrosis, reactive edema due to altered weight-bear-
  ing and biomechanics or arthritic changes. In one
  study of 17 asymptomatic basketball players, 14 were
  found to have bone marrow edema (41%) suggesting
  that MR findings should be taken in concert with the
  clinical presentation (Major and Helms, 2002).


• Bone marrow contusion patterns seen on MR imaging
  often correlate with the mechanism of injury. For
  example, a valgus load applied to the knee, when the
  knee is in a degree of flexion, as in cases of clipping
  injuries in football or skiing injuries, result in tears of
  the anterior cruciate ligament (Sanders et al, 2000).
  The tibia anteriorly subluxes, and the posterolateral
  margin of the tibia impacts against the lateral femoral
  condyle (Fig. 56-5(a)). The bone marrow contusion

FIG. 56-3 Coronal fast spin echo image demonstrating a

normal medial collateral ligament (arrows).

FIG. 56-4 Axial fast spin echo image demonstrating normal
uniform thickness of articular cartilage over the patellar facets.

FIG. 56-5(a) Sagittal fat suppression image demonstrating bone

marrow contusion pattern involving the anterior aspect of the lat-

eral femoral condyle and the posterolateral aspect of the tibia.