Minimizing the effects of knee brace migration

The data provided by this study shows that knee brace movement can be minimized with the application of a custom fitted brace. This is significant as the mechanical function of these braces in reducing various forces at the knee is not altered. Miller, Ronald et al.

acl-brace-parallel-bars

Columbia River’s Jordan Hess competes on the uneven bars with a torn ACL. Paul Valenicia, Columbia High School Sports, Vancouver WA.

By Shalmali Pal, Lower Extremity Review June 2012

Too many knee braces just won’t stay put, which can affect compliance and possibly even device effectiveness. Research on the topic is scarce, but experts say the key to minimizing knee brace migration is making sure the device fits the patient’s anatomy as closely as possible.

Many professional athletes rely on good luck charms for game-day success. These personal talismans can range from jewelry to a favorite meal to a “blessed” pair of shorts or socks (unwashed, of course). But rarely does an athlete sit down on a locker room bench and don his lucky knee orthosis before a big game.

One could argue that knee braces do come with an element of good fortune, whether that involves prophylactically protecting the knee from injury, reducing the risk of recurrent injury, or facilitating postoperative healing. But practitioners say the reality is that most athletes, regardless of the benefits of a brace, see it as a burden rather than a blessing.

“When I was a team physician…[knee brace] compliance during the game depended on the score,” explained Jonathan Chang, MD, an orthopedic surgeon with Orthopedic Surgery & Sports Medical Group in Monterey Park, CA. “So if a team was not doing well, the players would look for any excuse and, often times, the brace became the scapegoat. It was blamed for slowing the player down and subsequently slowing the team down.”

cti-oa-up-high-ossur_Page_008The main complaint with knee braces? Migration.

A 1998 study in the Journal of Sports Rehabilitation on func­tional knee brace migration found that under exercise conditions, braces can migrate anywhere from 0.25 mm to 11 mm. And although brace technology has made tremendous strides—now featuring lighter, stronger materials and strapping that allows for instant customization—migration still can prove annoying, uncomfortable, and possibly even render the brace less effective. For athletes in particular, the perception that brace migration hinders performance may fuel their concerns that device wear could potentially reduce their speed and agility.

Lower Extremity Review spoke with a trio of experts on the prevalence and consequences of brace migration, along with solutions they’ve devised to keep a brace on a player and the player in the game.

Heading south
The experts agreed that distal migration is the main problem with knee orthoses, whatever their intended use–offloading braces, prophylactic braces, or postoperative braces.

“In general, the brace tends to migrate south; it goes down the leg due to gravity,” said Barton Anderson, MS, ATC, AT, assistant professor and clinical education coordinator in the athletic training program at A.T. Still University in Mesa, AZ.

Migration in the opposite direction is less likely.

“For virtually everybody, the thigh is a lot larger than the lower leg so the likelihood of the brace migrating proximally would be very low,” Chang added.

The same holds true for rotation—possible but pretty rare. That kind of rotation also means that the orthosis is most likely migrating distally and proximally as well, explained Michael Carroll, CO, of the Hanger Clinic in Oklahoma City, OK.

While brace migration is unpleasant, does it cause biomechan­ical problems? Definitely.

“Typically, when we are providing a knee orthosis to a patient, it’s because they have a knee that’s in need of support,” Carroll said. “If this support is being supplied incorrectly by the knee orthosis, the patient doesn’t benefit from the device. The brace needs to provide adequate control in order to provide the right support.”

Chang put it quite simply: “If the brace doesn’t stay where it should, it certainly can’t protect the knee.”

Continue reading in Lower Extremity Review

Effect of Physical Activity on Knee Migration and EMG Activity of the Leg, John P. Miller PhD ATC, Ronald V. Croce PhD, University of New Hampshire. Journal of Athletic Training (32) 2:S-15, 1998. This information was also presented at the 1998 National Athletic Trainers’ Association, NATA Annual Meeting & Clinical Symposia.

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