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Abstract & Commentary
Synopsis: It is important to identify the syndesmotic ligament injury and anticipate that a substantial proportion of even athletically fit individuals will not recover quickly from what appears to be a "simple" ankle sprain.
Source: Gerber JP, et al. Persistent disability associated with ankle sprains: A prospective examination of an athletic population. Foot Ankle Int 1998;19(10):653-660.
A prospective observational study was carried out on all the cadets at the United States Military Academy who presented with ankle injuries during a two-month period. A standardized treatment program for ankle sprains was performed, and all of the injured ankles were reevaluated at six weeks and six months, subjectively, by physical examination, and through functional testing. There were 104 injuries over this two-month time span, with 96 sprains, seven fractures, and one contusion. Sixteen (17%) of the ankle sprains were syndesmosis injuries—injuries of the anterior tibiofibular ligament caused by an external rotation force. This is a higher incidence than reported by others.
While 95% of the injured cadets had returned to sports activities by six weeks, 55% of them reported loss of function and the presence of intermittent pain. Twenty-three percent had some persistent functional impairment as well. Even at six months, while all had returned to full activity, 40% had residual symptoms. A surprisingly high percentage of those with residual symptoms were in the syndesmosis sprain group.
Comment by James D. Heckman, MD
The simple ankle sprain may not always be so simple. This group of very fit, highly competitive individuals at the United States Military Academy, despite treatment in a rigorously controlled environment, frequently had persistent symptoms as long as six months after the injury. Gerber and associates identify the syndesmotic sprain as a particular cause of prolonged disability. We usually think of the lateral ligament complex (anterior talofibular and fibulocalcaneal ligaments) as being the ligaments susceptible to injury at the time of a sprain. Often, the syndesmosis is overlooked. Injury to the syndesmosis can be easily identified by careful palpation over the area of the anterior tibiofibular ligament, performing an external rotation stress of the talus in the ankle mortise that will put tension on this ligament,1 and by performing the "squeeze test."2 This review indicates even a mild syndesmotic sprain may continue to be symptomatic for up to six months and suggests that more aggressive early treatment, perhaps even with the temporary use of an air cast or fracture boot, might facilitate the healing of these syndesmotic injuries. For these injuries, I do not hesitate to provide an initial period of cast immobilization for 10 days to two weeks to facilitate early soft tissue healing.
The study shows that it is important to identify the syndesmotic ligament injury and anticipate that a substantial proportion of even athletically fit individuals will not recover quickly from what appears to be a "simple" ankle sprain.
1. Boytim MJ, et al. External rotation stress test: Syndesmotic ankle sprains. Am J Sports Med 1991; 19:294-298.
2. Hopkinson WJ, et al. The squeeze test: Syndesmosis sprains of the ankle. Foot Ankle Int 1990;10:325-330.