Knee injuries after a traumatic hip dislocation can be hard to diagnose. Injury or damage to the bone called bone bruising doesn't always show up on X-ray.

If there's no visible evidence of injury, painful symptoms may go away over time with healing. However, some damage may not be seen without an MRI.

A recent study of knee injuries in patients with traumatic hip dislocations showed a 93 percent rate of abnormality. Some were even in knees that weren't painful!

Magnetic resonance imaging (MRI) was used to find evidence of these additional soft tissue injuries. Knee injuries were divided equally between swelling, bone bruising, and meniscal tears.