By Jordana Bieze Foster
Net gain for ankle bracing
But not all devices benefit all players
Rigid and semi-rigid ankle braces may help prevent inversion ankle sprains in female volleyball players with no previous history of sprain, according to research published in the April issue of Foot & Ankle International.
In a single-season study of 999 male and female high school volleyball players, a rigid brace and a semi-rigid brace were associated with decreased rates of ankle sprain in those who had not previously suffered a sprain. Although those reductions were seen for the entire study population, other findings from the study suggested that the 592 female players experienced the greatest benefits.
Of the 273 players who wore a non-rigid brace, female athletes had a significantly higher rate of ankle sprain than their male counterparts. And the female players who wore the non-rigid brace were significantly more likely to experience an ankle sprain than those who wore a semi-rigid or rigid brace. The authors hypothesized that the gender differences may be related to increased levels of ligamentous laxity previously found in female athletes, which a more rigid external support might help to offset.
“Prophylactic ankle brace use is recommended for female volleyball players, especially those who have not had a previous sprain. Based on our data, however, we could not strongly recommend prophylactic ankle brace use for male high school volleyball players,” said Carol Frey, MD, director of orthopedic foot and ankle surgery at West Coast Center for Orthopedic Surgery and Sports Medicine in Manhattan Beach, CA, and lead author of the study.
The study included varsity high school volleyball players in Los Angeles county. Five different types of ankle braces, donated by brace manufacturers, were randomly distributed to the players, with a control group of 42 athletes who did not wear a brace. Each player was given one brace and instructed to wear it on his or her dominant limb (opposite the hitting arm) in all practices and games during the season.
Inversion ankle sprains occurred in 89 of 957 braced athletes (9.3%) and four of 42 controls (9.5%). In the group overall, use of any type of brace did not significantly affect risk of ankle sprain compared to the control group. Significant differences were seen only in those with no history of previous sprain, and then only for two of the devices, one rigid and one semi-rigid.
A previous study, published in the February 2008 issue of the American Journal of Sports Medicine, reported that use of a rigid ankle brace in female collegiate volleyball players resulted in an ankle sprain rate that was significantly lower than the National Collegiate Athletic Association average during the same seven-year period. Nearly half of the subjects in that study had a previous history of ankle sprain. However, the Manhattan Beach authors noted in their paper that the collegiate study did not specify the extent to which the NCAA comparison data included injuries sustained while wearing a brace.
Because ankle sprains in volleyball often occur when one player’s foot lands on the foot of an opposing player under the net, Frey and colleagues hypothesized that the mechanical forces involved in such an event may be greater than many external ankle supports are able to withstand. Strength and conditioning, they suggested, may be more important than bracing for preventing inversion injuries in such situations.
In the March issue (“Study finds three ankle foot orthoses equivalent for post-stroke hemiplegia,”) it was incorrectly stated that lower-durometer dorsiflexion-assist joints would likely provide more of an assist. The sentence should have read “higher-durometer” instead of “lower-durometer.” The online version of this article has been corrected.
Propriception, balance fail to explain orthoses’ effects on gait variability
Ankle orthoses do not significantly affect proprioceptive thresholds or single-leg balance in patients with peripheral neuropathy, according to research from the University of Michigan.
The findings, published in the May issue of the American Journal of Physical Medicine & Rehabilitation, suggest that improvements in gait variability associated with ankle orthoses in patients with peripheral neuropathy result instead from the device’s mechanical effect of stiffening the ankle.
Researchers assessed unipedal stance time and frontal plane ankle proprioceptive thresholds during bipedal stance in 11 patients with peripheral neuropathy (average age 72 years), with and without ankle orthoses. They found that the orthotic condition had no significant effect on either measure.
In a previous study, researchers from the same group found that use of semi-rigid ankle orthoses significantly decreased step-width and step-time variability in 42 patients with peripheral neuropathy. That study was published in the April 2004 issue of the Journal of the American Geriatric Society.
The May study’s findings suggest that these changes in variability are not attributable to changes in proprioceptive thresholds or unipedal balance.
Fracture patients have more to bear in pneumatic brace vs. fiberglass cast
When instructed in partial weightbearing, patients recovering from fractures put more weight on the injured limb while wearing a prefabricated pneumatic brace than they do in a fiberglass cast, according to a British study.
Investigators from Nevill Hall Hospital in Abergavenny, UK, assessed 117 patients with metatarsal or ankle fractures who were capable of partial weightbearing. Seventy two patients wore prefabricated pneumatic braces, while 45 received fiberglass casts. All were trained to allow the injured limb to support 50% of their body weight, then the actual percentage of body weight was measured during three attempts to replicate the training.
Casted patients were able to bear a mean of 48.48% of their body weight on the injured limb, while braced patients were able to bear a mean of 68.85%, a statistically significant difference. The findings were published in the April issue of Foot & Ankle Specialist.
The authors suggested that increased weightbearing in a pneumatic brace might facilitate rehabilitation in most fracture patients, but could be a concern in those with unstable fractures.