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For other articles and previous issues click here. January 16, 2006 Game
Film — Tackling Tough Injury Diagnoses Studying x-ray and MR images of college football players trying out for the NFL may earn big gains in diagnosing hard-to-find football injuries. Football, soccer, and basketball players, skiers, and other athletes are highly susceptible to ankle sprains. Pedestrians, too, can suffer ankle sprains just by stepping off a curb or slipping on ice. Between 850,000 and 1 million Americans sprain their ankles every year. Any sudden sideways or twisting movement of the foot can result in an ankle sprain—when the ligaments of the foot stretch too far or are torn. Most foot sprains are low rather than high-ankle sprains. That’s the good news because high-ankle sprains are generally harder to diagnose and more difficult to treat than low ankle sprains. Generally, out of 100 ankle sprains, only one to 15 will be high-ankle sprains, says Jeffrey D. Towers, MD, vice chairman of clinical radiology and associate professor of radiology and orthopaedics and musculoskeletal division chief of the University of Pittsburgh Medical Center (UPMC). UPMC Sports Medicine is the sports medicine provider for the Pittsburgh Steelers. The team’s practice and training facilities are located at the UPMC Sports Performance Complex in Pittsburgh’s South Side. However, Towers, a radiologist for the Pittsburgh Steelers, has found from studying candidates for the National Football League (NFL) draft that high-ankle sprains may be even more common than previously thought—especially among elite athletes. As part of his job with the Steelers, Towers travels to the NFL’s scouting combine held annually in Indianapolis a few weeks after the Super Bowl. The combine is where the invitation-only candidates for the NFL draft are put through various physical and mental challenges so team officials can evaluate them for possible selection in the draft. Approximately 350 football players from across the country attend the combine. “It’s four to five days of pretty intense work to evaluate all these athletes,” Towers says. Helmets
and Images As a researcher, Towers says, the imaging studies of the candidates provide a tremendous opportunity. “You have [the] opportunity to see patterns of injury that would take you years to see in a typical athletic practice, where you may have 50 guys on a team. Here, you have 350 people and you can get a snapshot of the distribution of injuries that are common among them.” This past year, Towers says, “in looking through ankle x-rays in candidates we knew had a high-ankle sprain by history, we noticed that a previously unrecognized pattern of new bone growth was very often seen.” In February 2005, Towers and his colleagues looked for this finding in all 354 ankle x-rays obtained at the combines and found that a larger number than expected had had high-ankle sprains, even in candidates who had never had such an injury documented. A high-ankle sprain is an injury to the syndesmotic ligament above the ankle that joins the tibia and fibula. The two bones run from the knee down to the ankle. “The fibula can move away from the tibia, and the cylindrical groove which forms the ankle can widen under load,” Towers says. High-ankle sprains are sometimes difficult to diagnose. They may not show on routine x-rays because the injury can be subtle; it’s not grossly misaligned. “It’s during athletic activity when the injury becomes most apparent,” Towers says. Hard
to Find One way to diagnose the injury is by physical exam—the physician squeezes the calf and rotates the ankle externally. Patients with high-ankle sprains will find the test painful. The problem with this finding is that one half of patients with a high-ankle sprain also have another ankle injury that may make the test painful as well, Towers says. High-ankle sprains tend not to heal as well as more common or lower-ankle sprains if not identified. Less serious ankle sprains will heal within a few weeks with rest and rehabilitation, but high-ankle sprains may require a much longer time off and a longer time without weight-bearing activity, Towers says. High-ankle sprains can take months to heal. Sending athletes with this injury back on the field can be problematic. In severe cases, surgery may be required to insert screws to hold the tibia and fibula bones in proper position while the syndesmotic ligament heals. Left untreated, Towers says, “high-ankle sprains can impede athletic performance and lead to arthritis.” Towers and his colleagues studied athletes’ x-rays and MRIs of the athletes to determine whether they could develop a better way of diagnosing high-ankle sprains. They found that 18 candidates for the 2005 professional football draft had a history of high-ankle sprain on either plain radiographs (18) or MRIs (two). Bone
Growth Towers believes the new bone growth seen on the x-rays and the finding of posterior malleolar periosteal stripping on the MRI are indicative of high-ankle injuries in elite football players. “Even if I don’t have MR images that include the entire syndesmosis, which goes into the lower leg,” he says, “if I look at an ankle and see this posterior periostosis, I can now be fairly sure of a syndesmotic injury.” The next step, Towers says, is to continue to study this finding and see how often it is right in diagnosing acute high-ankle sprains. Eventually, Towers says, he hopes their finding will lead to earlier and better method of diagnosing high-ankle sprains in an acute setting. “We think this is going to be an important way to differentiate high and low ankle sprains in an acute setting,” he says, “and could apply to anyone who hurts his or her ankle and who has symptoms beyond what is expected from a typical sprain.” Some orthopedists have informally known that bone growth is seen in people with high-ankle sprains, “but they just never reported it in the past,” Towers says. Towers says if the study eventually results in a better method of diagnosing high-ankle sprains, it would be significant. “You wouldn’t lose people to inappropriate treatment or follow-up care because you weren’t able to properly diagnose their injury in the acute or near acute setting.” Knee
Ligaments They found 57 tears of the lateral meniscus, a flat, disc-shaped ligament that supports the outer knee joint, and 26 tears of the medial meniscus, which supports the inner knee joint. Like the findings of the high-ankle sprains, “these findings are remarkable because the authors of most previous studies have reported a predominance of medial meniscal injuries,” Towers says. Towers says that at first, he suspected the unusually high percentage of lateral meniscal tears to be associated with anterior cruciate ligament (ACL) tears. ACL tears are fairly common among elite college football players and are commonly associated with lateral meniscal tears. ACL tears often occur when the knee is twisted from its normal position, often during contact from the outside. ACL tears can also occur without contact when the knee is pivoted; the athlete plants his or her foot and suddenly changes direction. The patient may also feel a “popping” in the knee that is associated with immediate swelling. Eighty percent of meniscal tears that occur in association with ACL tears are in the outer knee joint. Towers explains that tackling is usually done from the outside of the knee, imparting a load that traps the lateral meniscus, in addition to tearing the ACL. He was surprised that his study showed that while 23 lateral and eight medial meniscal tears were found in conjunction with ACL tears, 36 lateral and 18 medial tears were isolated injuries. “What we found is that almost two-thirds of the lateral meniscal tears were not in the setting of ACL tears,” Towers says. “So we concluded that in elite football players, lateral meniscal tears were more frequently found both in association with ACL tears and as isolated injuries.” Towers hopes that the discovery of this high incidence of lateral meniscal tears among elite athletes will have a significant impact on improving physicians’ ability to diagnose and treat this condition as well. “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 says. Risky
Positions? Coauthors on both studies were Kenneth Buckwalter, MD, a professor of radiology at Indiana University, where the combine takes place; Derek Armfield, MD, an assistant professor of radiology at UPMC; John Norwig, head trainer for the Pittsburgh Steelers; and James Bradley, MD, head team physician for the Pittsburgh Steelers since 1991, and past president of the NFL Physicians Society. Bradley also serves on the NFL Injury and Safety Panel. —
Beth W. Orenstein is a freelance medical writer based in Northampton,
Pa., and a regular contributor to Radiology Today.
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