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TUESDAY, July 22 (HealthDayNews) -- A new study offers recommendations for diagnosis and treatment of a rare but potentially devastating kind of football injury called hip subluxation.

The Duke University Medical Center research says prompt diagnosis and treatment of this injury -- often dismissed as a hip strain or sprain -- is essential because up to 25 percent of hip subluxation injuries may lead to bone death within the hip joint.

That bone death, brought on by a lack of adequate blood supply, can cause the joint to collapse. The patient then needs an artificial hip joint or a vascularized bone transplant.

Hip subluxation is a partial dislocation of the joint, where the ball at the top of femur moves in and out of the joint without tearing the capsule surrounding the joint. This injury is different than a complete hip dislocation, where the ball on top of the femur pops completely out of the joint.

"Hip subluxation is an unusual, although potentially devastating, injury that is an inherent risk of participating in American football," researcher Dr. Claude T. Moorman, orthopedic surgeon and director of the sports medicine program at Duke, says in a news statement.

The study, published in the July issue of the Journal of Bone and Joint Surgery, included eight football players who sustained traumatic hip subluxation. Two of the eight developed bone death within the hip joint.

It can be a challenge to doctors to diagnose hip subluxation, which can't be detected using standard X-rays. The study found that magnetic resonance imaging (MRI) can detect the injury and can also alert doctors to early signs of bone death.

Players who suffer hip subluxation should stay on crutches for at least six weeks, without putting any weight on the hip. If an MRI reveals no early signs of bone death, the player can slowly resume normal activities.

More information

Here's where you can learn more about hip injuries.