Bone Bruise

A 91-cm (3-ft) fall into a bilge sparked significant pain in the left knee of a 41-year-old man who landed on his left leg. Three days later, physicians found minimal effusion in the knee and medial collateral ligament tenderness.

Roentgenograms revealed no abnormalities, but MRI studies demonstrated a bruise of the left lateral femoral condyle and a minimal sprain of the left medial collateral ligament. T1-weighted images defined the bone contusion as a traumatic, nonlinear, dark area of signal loss involving the epiphysis and part of the metaphysis; the articular cartilage appeared normal. The sprained medial collateral ligament is depicted as a dark gray area on another T1-weighted MRI.

Bone bruises usually resolve within several months. This patient was given a knee splint and nonsteroidal anti-inflammatory agents until his symptoms abated. Physical therapy for knee rehabilitation may be helpful for some patients.