Braces' joint effects spur research surge

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From Biomechanics Magazine February 2005

Braces' joint effects spur research surge by Andria Segedy

How a joint articulates between bones has researchers and clinicians taking a

closer look at the interdependence of joints in the context of bracing. The

effect

of ankle bracing on the knee, for example, has received the most attention in

the

literature.

Evidence suggests that ankle supports may transfer loads to other joints,

putting

them at risk for injury, according to a literature review by Brent Arnold, PhD,

an

associate professor of exercise science at Virginia Commonwealth University in

Richmond, VA.1

Conventionally aligned ankle foot orthoses increase demand on the knee extensor

muscles that can be ameliorated by realigning a device to account for shoe heel

height, according to a study at Northwestern University in Chicago.2

But the question of whether protecting against injury at one joint may lead to

further injury at another joint still remains, said Tyler, MSPT, ATC, a

clinical research associate at the Institute of Sports Medicine and

Athletic Trauma (NISMAT) at Lenox Hill Hospital in New York.

" We have to be conscious and aware of that, but I can't say whether that cause

and effect is there, " Tyler said. " We see athletes who have an ankle sprain and

later injure a knee. Whether it is a cause and effect relationship, I don't

know. "

Wen Liu, PhD, has heard other practitioners make similar observations.

" I don't think there is an answer yet. Our study3 adds some information to that

debate, " said Liu, an assistant professor of physical therapy at the University

of

Kansas in Kansas City.

Does wearing an ankle brace affect the knee?

" That's the question to which everyone is looking for the answer, " Liu said.

" Our

study is just one small step toward that direction. "

In Liu's study, 10 healthy subjects performed trunk-turning movements while

standing on one leg, with and without a prophylactic ankle brace. They turned

sideways to catch a ball or touch a target with the shoulder. When the ankle

brace was used, subjects had reduced trunk axial rotation during the

ball-catching tasks and increased knee axial rotation during the

target-touching

tasks.

" Our research showed two results, " Liu said. " If we didn't constrain trunk

motion

and just asked subjects to catch a ball, they compensated for the ankle

restriction by increasing motion in the shoulder or the arm. They did not show

increased motion of the knee. When the subjects were required to rotate the

upper body a certain number of degrees, then there was an increased motion in

the knee with the use of the ankle brace. "

In most cases, while using an ankle brace, a person will not put more stress on

the knee, said Liu, who does not discourage the use of ankle braces.

" However, under certain conditions, we are forced to create a motion and we

may load the knee to a greater degree, " he said.

Further research will be on ankle instability and the effect of an ankle brace

on

the knee joint, Liu said.

Should athletes not play if they wear an ankle brace?

" If they are tired, they should sit on the bench, because being tired is a big

factor in being injured, " he said.

When Tyler does prescribe ankle braces for his patients, it's usually in

postinjury

situations.

" We don't do prophylactic bracing anymore, " he said. " The literature doesn't

support it in the knee or the ankle.4-7 With an acute ankle injury, we'll do a

rigid

brace. As we take athletes through rehabilitation with motion, strength, and

proprioception training, we'll put them in a lace-up brace. "

Ankle bracing is an added support to get athletes into competition quicker

without jeopardizing their health, Tyler said.

" We have them wear the brace up until a year after the initial injury. They are

also doing rehab. Bracing does not replace a good rehab program, " he said.

Knee bracing research

The high school, college, and professional athletes Tyler works with can become

dependent on braces for the knee, ankle, or shoulder. Prophylactic knee

derotation braces do not prevent injuries, but athletes come to need them,

Tyler

said.

" We all, as trainers, have athletes who can't play without their braces, " he

said.

Patellofemoral bracing can reduce joint stress because it increases the

patellofemoral contact area, according to M. Powers, PhD, PT, an

associate professor of biokinesiology and physical therapy and director of the

Musculoskeletal Biomechanics Research Laboratory at the University of Southern

California in Los Angeles, whose findings are supported by his research.8-10

He is considering research to see whether the same effects produced by

patellofemoral bracing can be achieved by strengthening the quadriceps as

opposed to using a passive device.

Which arthritic knee patients will have a successful outcome after wearing an

unloading brace is a question being addressed by researchers led by Darren

, MD, chair of orthopedic surgery at the University of Kentucky in

Lexington.

" Our physicians want to develop better criteria that they can use to prescribe

these braces to their patients, " said Tim Uhl, PT, PhD, ATC, an assistant

professor of athletic training in the same department who's spearheading the

research.

Investigators will characterize subjects who have done well using an unloading

brace and those who have not, Uhl said. They will look at body mass index, bony

alignment by taking a weight-bearing x-ray, the subject's physical activity

level,

body fat that could affect the fit of a brace, and a 3D gait analysis.

He said they hope to have about 20 subjects and complete the study in a year.

The twist to this study, Uhl said, is to see if one or several of the

characteristics

will reveal a meaningful difference between the two groups. Next would be a

prospective study to follow patients who are prescribed an unloading brace and

determine which have positive outcomes from wearing such a brace, he said.

Shoulder bracing

For shoulders, Uhl said, some published research shows the effectiveness of

different bracing techniques. Researchers from Arizona State University, for

example, demonstrated improved joint reposition sense-a measure of

sensorimotor control-in subjects with unstable shoulders11 (see " Shoulder brace

decisions weigh stability against functionality, " June, page 43).

Research from the University of Virginia, on the other hand, indicated that

shoulder braces restricted shoulder motion.12

" We studied a variety of braces under the same principle of restricting

shoulder

motion, " Uhl said. " There is no doubt they do that. The problem is, as you put

the subject through exercises and sport-specific tasks, the braces all loosened

up to some extent. "

An article from Temple University13 came to the same conclusion, Uhl said.

Uhl also referred to research on the nonoperative treatment of shoulder

instability and the use of braces.14 Thirty athletes with shoulder instability,

age

17 to 20, were studied over a two-year period. Of those, 26 were able to return

to their sport to complete the season, missing about 10 days. Ten athletes

suffered sport-related recurrent instability.

" Bracing helps you get through a season, but physicians will tell you: if there

is

significant shoulder instability, the best thing is to operate, " Uhl said.

Orthopedic surgeon Reuss, MD, agrees.

" We don't feel bracing for shoulder instability is very effective as the

ultimate

management of the injury, " said Reuss, with the Orlando Regional Healthcare

System in Florida. " We think it should be treated surgically, but an athlete in

the

middle of a season can get by with a brace. "

Reuss and coauthor Nowicki, MD, updated a 1997 article of Nowicki's that

reviewed shoulder braces.15 Their article,16 published in June, reviewed

comfort,

cost, what the braces look like, how they restrict motion, and how they affect

motion. It wasn't a scientific study, but it could help practitioners make

recommendations, Reuss said.

Shoulder bracing is used at NISMAT, said Tyler, who noted that some literature

does support bracing for acromioclavicular joint separations.13

" Unfortunately, for the contact athlete with a dislocated shoulder, bracing

doesn't prevent the shoulder from dislocating. But bracing does provide some

proprioceptive feedback to the throwing athlete or the noncontact athlete, " he

said.

Andria Segedy is a contributing editor to BioMechanics.

References

1. Arnold BL, Docherty CL. Bracing and rehabilitation-what's new. Clin Sports

Med

2004;23(1):83-95.

2. AR. AFO alignment affects knee joint, study finds. BioMechanics

2004:11(7):17.

3. Santos MJ, McIntire K, Foecking J, Liu W. The effects of ankle bracing on

motion of the knee and the hip joint during trunk rotation tasks. Clin Biomech

(Bristol, Avon). 2004;19(9):964-971.

4. Olmsted LC, Vela LI, Denegar CR, Hertel J. Prophylactic ankle taping and

bracing: a numbers-needed-to-treat and cost-benefit analysis. J Athl Train

2004;39(1):95-100.

5. ek V, Friederich NF. To brace or not to brace? How effective are knee

braces in rehabilitation? Orthopade 1999;28(6):565-570.

6. Bot SD, van Mechelen W. The effect of ankle bracing on athletic performance.

Sports Med 1999; 27(3):171-178.

7. Rovere GD, Haupt HA, Yates CS. Prophylactic knee bracing in college

football.

Am J Sports Med 1987;15:111-116.

8. Powers CM, Ward SR, Chen YJ, et al. The effect of bracing on patellofemoral

joint stress during free and fast walking. Am J sports Med 2004;32(1):224-231.

9. Powers CM, Ward SR, Chan LD, et al. The effect of bracing on patella

alignment and patellofemoral joint contact area. Med Sci Sports Exerc

2004;36(7):1226-1232.

10. Powers CM, Ward SR, Chen YJ, et al. Effect of bracing on patellofemoral

joint

stress while ascending and descending stairs. Clin J Sports Med

2004;14(4):206-214.

11. Chu J, Kane EJ, Arnold BL, Gansneder BM. The effect of a neoprene shoulder

stabilizer on active joint-reposition sense in subjects with stable and

unstable

shoulders. J Athlet Train 2002;37(2):141-145.

12. McLeod IA, Uhl TL, Arnold BL, Gansneder BM. Effectiveness of shoulder

bracing in limiting active range of motion. J Athlet Train 1999;34(2):S-84.

13. Weise K , Sitler MR, Tierney R, Swanik KA. Effectiveness of glenohumeral

joint

stability braces in limiting active and passive shoulder range of motion in

collegiate football players. J Athl Train 2004;39(2):151-155.

14. Buss DD, Lynch GP, Meyer CP, et al. Nonoperative management for in-season

athletes with anterior shoulder instability. Am J Sports Med

2004;32(6):1430-1433. Epub 2004 Jul 20.

15. Harding WG 3rd, Nowicki KD, Perdue PS Jr, et al. Managing anterior shoulder

instability with bracing. J Musculoskel Med 1997;14(6):50-58.

16. Reuss BL, Harding WG III, Nowicki KD. managing anterior shoulder

instability

with bracing: an expanded update. Orthopedics 2004;27(6):614-618.

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