MSK MR goes deep to uncover football injuries

Football coaches can't foresee when their players might get injured. But musculoskeletal radiologists may predict who is going to hurt the most, and where.

Knee and ankle ligament injuries vex contact sport athletes. Football players, in particular, put up with torn menisci and a condition known as high ankle sprain that usually gets misdiagnosed. Findings from two studies presented at the 2005 RSNA meeting provide new insight on the diagnosis and management of these injuries, said principal investigator Dr. Jeffrey Towers, an associate professor of radiology at the University of Pittsburgh Medical Center.

In the first study, Towers and colleagues at Pittsburgh and the University of Indiana reviewed 101 MR exams from 330 candidates for the 2005 professional football draft. They confirmed 57 lateral and 26 medial meniscal tears. Existing clinical data report mostly on medial meniscal tears, which affect the inner knee joint. The investigators speculated that the unusually high percentage of lateral lesions correlated with anterior cruciate ligament tears.

Eighty percent of injured menisci associated with ACL tears affect the outer knee joint. Tackling, which usually hits the outside of the knees, can tear both the lateral meniscus and the ACL.

The study, however, found that three-quarters of the lateral meniscal tears were isolated injuries. And the highest incidence of these lesions occurred in linemen and defensive secondary players - tacklers, not tacklees.

The discovery may have a significant impact on improving physicians' ability to diagnose and treat this condition. It may also help prevent it, Towers said.

"The fact that we found a concentration of lateral meniscal tears could mean that there's something about this sport that predisposes athletes to this injury," he said. "Now that we recognize this, there may be ways to address the players who are the most at risk for this injury."

The second paper by the same research team identified for the first time an indirect sign of syndesmotic tear. Routine imaging may not find the tear affecting the ligament holding the tibia and fibula together. The condition becomes apparent mostly during physical activity. Painful physical examination is the current diagnostic standard.

Eighteen candidates for the 2005 pro football draft who had a history of high ankle sprain underwent x-ray and MR exams. X-rays showed periostosis - abnormal bone growth - at the lower part of the tibia in 14 patients. MRI revealed abnormal swelling and fluid at the same site in two patients.

Treatment for a high ankle sprain differs from that for a typical ankle sprain and generally takes longer. Hidden, untreated high ankle sprains can disrupt performance and lead to permanent impairment, Towers said.

"If it is not recognized, and you send somebody out to play, the ligaments heal improperly, the ankle doesn't fit as tightly as it should, and often the result is arthritis," he said.

Periostosis provides physicians with an indirect sign of high ankle sprain that helps detect this otherwise hard-to-spot injury. Radiologists can diagnose even without MR images of the entire syndesmosis.

"If I look at an ankle and see this posterior periostosis, I can be fairly sure of a syndesmotic injury," he said.

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