MRI can predict recovery time for syndesmotic ankle sprains

A study in NFL players indicated severity of sprain correlated with prolonged time away from game.

Issue: October 2010

Magnetic resonance imaging can aid in predicting how much time professional football players require for recovery from syndesmotic ankle sprains, according to a new study.

Previous research into syndesmotic ankle sprains in athletes found that professional hockey players missed an average of 45 days, and college football players needed 31 days before returning to play. Robby Singh Sikka, MD, a medical resident in orthopedic surgery at the University of Minnesota in Minneapolis, and colleagues conducted a retrospective study involving three National Football League teams and syndesmotic ankle injuries occurring between 1993 and 2007.

Regular-season injuries

There were 43 clinical diagnoses of syndesmotic injury, and 36 of those were included in the final analysis. Players were excluded if any evidence of fracture was found; only injuries that occurred during the NFL regular season and those where the player had an MRI within 48 hours of injury were included.

“Our hypothesis was that there was an association with the length of interosseous membrane tear and the presence of bony contusions with prolonged disabilities,” Sikka said at the 2010 Annual Meeting of the American Orthopaedic Society for Sports Medicine.

Thirty patients had a positive external rotation stress test, and 23 had a positive squeeze test. The investigators created a grading system for the injuries, with grade I representing an isolated injury to the anterior tibio-fibular ligament; grade II involved injury to both the anterior tibio-fibular ligament and the interosseous ligament; injury to those two ligaments with injury to the posterior tibio-fibular ligament were deemed grade III; and grade IV injuries involved a grade III with additional involvement of the deltoid ligament.

Though Sikka said they expected most injuries to be grade I or II, there were in fact far more grade III and IV sprains. Three players had grade I sprains, three had grade II, and 27 and three had grades III and IV, respectively.

More serious sprains

“We found that there was an increase in the amount of disability and missed playing time as the severity of the injury increased,” Sikka said. Players missed an average of 3.3 games and 16.7 practices.

Eight players had bony contusions, and seven of those missed at least one game. Sikka also noted that the presence of bony contusions was associated with more severe ligamentous injury. Nine players had chondral defects, and eight of those players also missed at least one game.

The study did have some limitations including its retrospective nature and the timing of all injuries during the regular season. Sikka said that all the grade IV injuries occurred during the last month of the season and all were season-ending; if the season had continued, there might have been further evidence of correlation between injury grade and prolonged disability.

“MRI findings can be used reliably to predict the amount of missed playing time and whether a player will have prolonged recovery times,” Sikka said. “Injury to the posterior tibio-fibular ligament as well as the presence of bony contusions and chondral defects may predict prolonged recovery. Our grading system can be helpful for trainers as well as physicians in predicting the amount of missed playing time.” – by Dave Levitan

Reference:
Sikka RS. Syndesmotic Ankle Sprains in Professional Football Players: Correlating MRI Appearance with Time of Disability. Presented at the American Orthopaedic Society for Sports Medicine 2010 Annual Meeting. July 15-18. Providence, RI.

Robby Singh Sikka, MD, can be reached at TRIA Orthopaedic Center, 8100 Northland Drive, Bloomington, MN 55431; 952-831-8742. robbysikka@gmail.com.

One of the most important roles of the team physician is to try to predict time to return to play. This is often one of the first questions asked by the athlete, coach, team manager, etc. Imaging studies that provide objective information about injury severity have become an important tool in the arsenal of the sports medicine physician.

Sikka and co-authors have demonstrated a correlation between an injury severity grading scale and time to return to play. This information may be very helpful to sports medicine physicians, since syndesmotic ankle sprains can often require an extended time for recovery. These “high ankle” sprains can be distinctly different than the more common lateral ligament injury. The finding of a correlation between MRI injury grade and time to return to play in this study is especially useful since there is sometimes a poor correlation between the apparent injury severity based on physical examination and the recovery time. Two common examples would be hamstring injury and concussions, where there can be a disconnect between the apparent severity based on the initial physical examination and the eventual time to resolution of symptoms. Thus, the information provided by Sikka et al will be helpful for sports medicine physicians.

This study also shows that syndesmotic injuries that extend to involve the posterior tibio-fibular ligament and/or deltoid ligament are more severe and have a longer recovery time. This information indicates that the physician should carefully examine these areas when evaluating these injuries. The finding that athletes with bone contusions and chondral defects also had a longer recovery time is novel information and supports the use of MRI to provide important prognostic information that can also guide return to play decisions.

– Scott Rodeo, MD
Co-Chief, Sports Medicine and Shoulder Service
Professor, Orthopaedic Surgery, Weill Medical College of Cornell University
Attending Orthopaedic Surgeon, The Hospital for Special Surgery
Associate Team Physician, New York Giants Football

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