Bone Contusion Patterns of the Knee at MR Imaging: Footprint of the Mechanism of Injury

Abstract

Bone marrow contusions are frequently identified at magnetic resonance imaging after an injury to the musculoskeletal system. These osseous injuries may result from a direct blow to the bone, from compressive forces of adjacent bones impacting one another, or from traction forces that occur during an avulsion injury. The distribution of bone marrow edema is like a footprint left behind at injury, providing valuable clues to the associated soft-tissue injuries. Five contusion patterns with associated soft-tissue injuries occur in the knee: pivot shift injury, dashboard injury, hyperextension injury, clip injury, and lateral patellar dislocation. The classic bone marrow edema pattern seen following the pivot shift injury involves the posterolateral tibial plateau and the midportion of the lateral femoral condyle. Edema occurs in the anterior aspect of the proximal tibia following the dashboard injury. Hyperextension results in the "kissing" contusion pattern involving the anterior aspect of the proximal tibia and distal femur. The clip injury results in a prominent area of edema involving the lateral femoral condyle and a smaller area of edema involving the medial femoral condyle. Finally, lateral patellar dislocation results in edema involving the inferomedial patella and anterior aspect of the lateral femoral condyle. In many instances, the mechanism of injury can be determined by studying the distribution of bone marrow edema, which then enables one to predict with accuracy the specific soft-tissue abnormalities that are likely to be present.

Posttraumatic Bone Marrow Lesion Volume and Knee Pain Within 4 Weeks After Anterior Cruciate Ligament Injury

“…[7][8][9] The location and size of a traumatic BML may be influenced by the mechanism of injury (ie, loading during injury) or the presence of concurrent injuries (eg, compression fracture, meniscal lesion, collateral ligament sprain). 4,[10][11][12][13][14][15] Therefore, the size and location of a traumatic BML within the first few weeks of an ACL injury may provide useful information about the initial injury. Furthermore, the size of a traumatic BML may relate to knee pain or symptoms either because it is a proxy for the severity of the initial injury or because the lesion causes knee pain.…”

Clinics in diagnostic imaging (163)

“…8). (1,4,14) Femoral bone contusions are usually more anterior and superior than the contusions in pivot shift injuries.…”

“…(5,6) The medial retinaculum is seen just distal to the MPFL and may not be separable. (5,14) Complete tears of the MPFL result in discontinuity with retraction or a wavy appearance of its fibres with surrounding oedema (Fig. 9b), while partial tears lead to fibre irregularity, thickening or partial discontinuity with intrasubstance and/or surrounding oedema (Fig.…”

The Pearls and Pitfalls of Magnetic Resonance Imaging of the Lower Extremity

“…There are often secondary signs of an anterior cruciate ligament (ACL) injury, such as a joint effusion and bone contusions. 33 Often, a reconstructed ACL graft can be seen on 1 slice through the notch (FIGURE 9). 30 The menisci should be evaluated for a tear using both their signal intensity and morphology.…”