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Mechanical Supports for Ankle Sprains

Author(s): Paul Auerbach
Posted: September 7, 2009

Much of how we know to practice medicine for the outdoors, including medicine in remote wilderness environments, comes from what we learn in the urban setting. For instance, I maintain my skills mostly in the Emergency Department at Stanford University. Because Stanford Hospital is a Level 1 trauma center, we care for many victims of all manner of injuries. So, in that practice, I care for persons with afflictions such as broken bones, burns, cuts, amputations, and so forth. What we do for these persons is usually directly applicable to what we might do for someone in an austere setting, with the proviso that we may need to help a victim in the wilderness with less support (equipment, assistance), for a longer time period, and under rugged non-optimal conditions. Adapting to the outdoor setting and learning to improvise when necessary are part of what make wilderness medicine a unique proposition.

One of the most common orthopedic injuries, in a wilderness or urban setting, is an ankle sprain. It ranks right up there with blisters and overuse syndromes and the musculoskeletal disorder that most frequently disables a participant and potentially slows or terminates that person’s participation in outdoor and athletic activities. So, the more we can know about how best to manage an ankle sprain (and also how to avoid one), the better.

There is a relatively recent study out of the U.K. that adds to our knowledge base regarding ankle sprain. In a document entitled “Mechanical supports for acute, severe ankle sprain: a pragmatic, multicentre, randomised controlled trial,” published in the Lancet, Professor SE Lamb D.Phil., JL Marsh Ph.D., JL Hutton Ph.D., R Nakash Ph.D. and MW Cooke Ph.D., on behalf of The Collaborative Ankle Support Trial (CAST Group) offered their observations. This was an emergency department-based study, as they noted that severe ankle sprains are a common presentation in emergency departments in the U.K. In their study, they aimed to assess the effectiveness of three different mechanical supports (Aircast brace, Bledsoe boot [“walking” boot], or 10-day below-the-knee cast) compared to a double-layer tubular compression bandage (similar to an Ace bandage wrapping) in promoting recovery after severe ankle sprains. The study was a multi-center, randomized trial with “blinded” assessment of outcome. Five hundred eighty-four participants suffering from severe ankle sprain were recruited between April, 2003 and July, 2005 from 8 emergency departments across the U.K. Participants were provided with a mechanical ankle support within the first 3 days of attendance by a trained healthcare professional and given advice on reducing swelling and pain. Functional outcomes were measured over 9 months. The primary outcome was quality of ankle function at 3 months. Patients who received the below-knee cast had a more rapid recovery than those given the tubular compression bandage. The investigators noted clinically important benefits at 3 months in quality of ankle function with the cast compared with tubular compression bandage, as well as in pain, symptoms and activity. The mean difference in quality of ankle function between Aircast brace and tubular compression bandage was measurable but less than that with the below-knee cast; there were little differences for pain, symptoms and activity. Bledsoe boots offered no benefit over the tubular compression bandage, which was the least effective treatment throughout the recovery period. There were no significant differences between tubular compression bandage and the other treatments at 9 months. Side-effects were rare with no discernible differences between treatments. In conclusion, for treatment of a severe ankle sprain, a short period of immobilization in a below-knee cast or Aircast results in faster recovery than if the patient is only given a tubular compression bandage. The authors recommended below-knee casts because they show the widest range of benefit.

What does this mean? It means that for a severe ankle sprain, the optimal immediate treatment to hasten short-term recovery and function is complete immobilization (in a position of function) if possible. This is most effectively accomplished with a cast or rigid splint, less effectively accomplished with a walking boot, and barely accomplished (if at all) with an elastic bandage wrap or taping. A sprain involves ligamentous injury, commonly one or more tears, which can heal best if kept immobile and in proper position.

The practicality of the method chosen depends on the setting. In the wilderness, casting or rigid splinting materials may not be available. Furthermore, the victim may need to walk to self-extricate, which requires a minimum amount of mobility and may necessitate the victim needing to fit his foot and ankle into a hiking boot or shoe. There are a number of pre-fashioned splints on the market. I usually carry at least one of these on any hike or trek when I will be a day or more away from a location where I can obtain a splint. The lighter ones provide reasonable rigidity, are lightweight, and do not consume much space in the medical kit or backpack.

Reprinted with permission by the Author from Healthline.com

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