Comparison of magnetic resonance imaging with operative findings in acute traumatic dislocations of the adult knee.

OBJECTIVES

To compare magnetic resonance imaging (MRI) with examination under anesthesia and with surgical findings in evaluating soft tissue injuries in acute traumatic knee dislocations in adults.

DESIGN

Retrospective analysis.

SETTING

Level I trauma center.

PATIENTS

For a single surgeon, all patients who underwent MRI before surgical treatment for knee dislocations (ten individuals).

INTERVENTION

Incompetent ligaments were repaired or reconstructed.

MAIN OUTCOME MEASUREMENTS

MRI of knee dislocations was compared with clinical examination under anesthesia and with intraoperative findings at arthrotomy in ten cases. Pertinent positive and negative findings were recorded, and accuracy, sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

Two mid-grade sprains of the anterior cruciate ligament were erroneously read as complete tears. One rupture or avulsion of each the biceps tendon, the lateral collateral ligament, and the posterolateral and posteromedial corners were considered intact on MRI. The MRI studies erroneously identified tears of the lateral collateral ligament and medial meniscus in one case each. Otherwise, the study was highly accurate.

CONCLUSIONS

MRI is useful for defining the presence of ligamentous injuries in knee dislocations; however, clinical examination under anesthesia is more accurate.