CRITICALLY APPRAISED TOPIC
Journal of Sport Rehabilitation, 2016, 25, 190 -194
© 2016 Human Kinetics, Inc.
Journal of Sport Rehabilitation, 2016, 25, 190 -194
© 2016 Human Kinetics, Inc.
Sugimoto, Micheli, and Kramer are with the Micheli Center for
Sports Injury Prevention, Waltham, MA. LeBlanc is with the
Dept of Physical Therapy, University of Massachusetts–Lowell,
Lowell, MA. Wooley is with the Dept of Physical Education and
Human Performance, Central Connecticut State University, New
Britain, CT. Address author correspondence to Dai Sugimoto
The Effectiveness of a Functional Knee Brace
on Joint-Position Sense in Anterior Cruciate
Dai Sugimoto, Jessica C. LeBlanc, Sarah E. Wooley, Lyle J. Micheli, and Dennis E. Kramer
It is estimated that approximately 350,000 individuals undergo anterior cruciate ligament (ACL) reconstruc-
tion surgery in each year in the US. Although ACL-reconstruction surgery and postoperative rehabilitation are
successfully completed, decits in postural control remain prevalent in ACL-reconstructed individuals. In order
to assist the lack of balance ability and reduce the risk of retear of the reconstructed ACL, physicians often
provide a functional knee brace on the patients’ return to physical activity. However, it is not known whether
use of the functional knee brace enhances knee-joint position sense in individuals with ACL reconstruction.
Thus, the effect of a functional knee brace on knee-joint position sense in an ACL-reconstructed population
needs be critically appraised. After systematically review of previously published literature, 3 studies that
investigated the effect of a functional knee brace in ACL-reconstructed individuals using joint-position-sense
measures were found. They were rated as level 2b evidence in the Centre of Evidence Based Medicine Level
of Evidence chart. Synthesis of the reviewed studies indicated inconsistent evidence of a functional knee
brace on joint-position improvement after ACL reconstruction. More research is needed to provide sufcient
evidence on the effect of a functional knee brace on joint-position sense after ACL reconstruction. Future
studies need to measure joint-position sense in closed-kinetic-chain fashion since ACL injury usually occurs
under weight-bearing conditions.
Keywords: anterior cruciate ligament reconstruction, effect size, ACL-R
It is estimated that approximately 350,000 individuals
undergo anterior cruciate ligament (ACL) reconstruction
surgery in each year in the United States. Although ACL-
reconstruction surgery and postoperative rehabilitation
are successfully completed, decits in postural control
remain prevalent in ACL-reconstructed individuals.
In addition, subsequent ACL-retear incidence can be
as high as 24%. To assist the lack of balance ability
and reduce the risk of retear of the reconstructed ACL,
physicians often provide a functional knee brace on an
athlete’s return to physical activity. The common belief
is that the functional knee brace provides mechani-
cal support. In addition, some clinicians argue that
external support provided by the functional knee brace
may enhance afferent nerve function around knee
joint, which, in turn, improves joint-position sense.
Through this mechanism, those who experience ACL
reconstruction maintain optimum balance ability and
decrease the future risk of ACL retear. However, it is
not known whether the use of a functional knee brace
enhances knee-joint position sense in individuals with
Focused Clinical Question
Does the use of a functional brace improve knee-joint
position sense in individuals who have undergone ACL
Summary of Search,
“Best Evidence” Appraised,
and Key Findings
• The literature was searched for studies of level 2
evidence or higher that investigated the effect of
a functional knee brace on joint-position sense in
ACL-R, Knee Brace, Joint-Position Sense 191
JSR Vol. 25, No. 2, 2016
• All 3 studies found used a crossover design.
• Two studies demonstrated statistical signicance for
the effect of a functional knee brace on joint-position
Clinical Bottom Line
There is inconsistent evidence that a functional knee brace
improves joint-position sense.
Strength of Recommendation: Level B evidence
exists that a functional knee brace improves joint-position
Terms Used to Guide Search Strategy
• Patient/Client Group: ACL-reconstructed individuals
• Intervention (or Assessment): functional knee brace
• Comparison: intervention (functional knee brace)
AND control (no brace)
• Outcome(s): joint-position sense
Sources of Evidence Searched
• Google Scholar
• Additional resources obtained via review of refer-
ence lists and hand search
Inclusion and Exclusion Criteria
• Studies investigating joint-position sense including
joint reproduction and detection of passive motion
in a braced versus unbraced condition.
• Level 2 evidence or higher
• Limited to English language
• Limited to humans
• Limited to publications from 1999 to 2014
• Studies that did not include individuals with ACL
• Studies that did not include a functional knee brace
• Studies that did not measure joint-position sense
Results of Search
Three relevant studies were identied and categorized
as shown in Table 1.
The studies shown in Table 2 were identied as the best
evidence and selected for inclusion in this critically
appraised topic (CAT). Reasons for selecting these stud-
ies were that they were graded with a level of evidence
of 2 or higher and included joint-position sense in a
braced versus unbraced condition in ACL-reconstructed
Implications for Practice,
Education, and Future Research
The 3 synthesized studies in this CAT demonstrated
inconsistent results in enhancing joint-position sense in
an ACL-reconstructed population. One study1 showed
superior active joint-repositioning sense with a functional
knee brace, whereas another study did not nd a differ-
ence in detection with passive motion between braced
or unbraced conditions.2 The other study3 reported more
accurate active joint-reposition sense in braced conditions
than in the unbraced condition; however, the effect-size
calculation did not indicate a signicant outcome of the
functional brace (Figure 1). It is interesting to note that
passive joint-position sense is less precise than in 2 other
studies that measured active joint-position sense.1–3 This
phenomenon can be explained by neuroanatomy and the
function of the ACL. Sensory nerves including mechano-
receptors, Rufni nerve endings, and Pacinian corpuscles
were found in the ACL bundles.4,5 Once the ACL was
ruptured, the sensory nerves were disrupted. Although the
ACL was reconstructed, the sensory nerve functions may
not have been fully recovered to detect external stimuli
such as a brace. Limited sensory nerve function may have
hindered passive knee-joint position sense.
Two of the studies1,3 used active joint-position sense
and reported greater accuracy than in nonbraced condi-
tions. However, these ndings need to be interpreted with
caution. In the effect-size comparison, a study conducted
by Wu et al1 demonstrated signicance (Figure 1). The
measurement methods were comparable between the
2 studies1,3; however, the only differences were the
participants. Both studies enrolled approximately 30
participants; the study performed by Birmingham et
al3 had 15 men and 15 women, compared with 28 men
and 3 women in the study of Wu et al.1 There was no
report that men performed better in joint-repositioning
Table 1 Summary of Study Designs
of Articles Retrieved
trial 3 Wu et al1
Risberg et al2
Birmingham et al3
192 JSR Vol. 25, No. 2, 2016
Table 2 Characteristics of Included Studies
Characteristic Wu et al
Risberg et al
Birmingham et al
Study design Single-blinded, crossover, laboratory study. Partici-
pants were asked to visit a laboratory and to repro-
duce specic knee-joint angles under 3 specic con-
ditions: functional knee brace (DonJoy), mechanical
placebo brace, and no brace. The mechanical brace
was used as a placebo condition, and the order of the
3 conditions was randomly determined.
Crossover (in which each subject served as own con-
trol) laboratory-controlled study. Participants were
asked to wear a functional knee brace and to detect a
passive motion with braced and unbraced conditions.
A healthy control group (5 men and 5 women) was
also recruited. The order of the 2 conditions (braced
and unbraced), direction of passive motion (extension
and exion), side of limb (right and left), and time
intervals between tests were randomized.
Crossover, laboratory study. Participants were invited to
a laboratory with their own custom-t functional knee
brace. Participants were asked to reproduce previously
targeted knee-joint angles. The targeted knee-joint angles
were randomized. Each participant experienced braced and
unbraced conditions. The order of the 2 conditions (brace
and unbraced) was randomized.
Participants Twenty-eight men and 3 women (mean age 26 y)
with ACL-reconstruction surgeries (ACL graft and
physical activity status were not documented).
Eight men and 12 women (mean age 35 y) who had
undergone ACL-reconstruction surgeries. All patients
received a bone-to-bone patella-tendon graft, and the
postoperative rehabilitation program was standardized.
All patients had a Tegner activity score of 5 or greater
before the reconstruction surgery. Mean Tegner activ-
ity score was 4.6 at the time of follow-up.
Fifteen men and 15 women (27.2 ± 11.3 y) with ACL-
reconstruction surgeries. Hamstring (semitendinosus/
gracilis tendons) graft was used. All participants had been
advised to resume previous physical activity.
investigated Reproducing knee-joint angle among functional knee
brace (DonJoy), mechanical placebo brace, and no
Participants were seated on computerized dynamom-
eter (Cybex) with 30° of hip exion and 80° of knee
exion. They were not allowed to see their legs. Their
legs were moved by operators at slow but steady
speed to a new position and stopped at that position.
Participants were then asked to indicate the position
of the leg by moving the shank of the cardboard knee
model. The angles indicated on both goniometers
This process was performed on the reconstructed
knee and compared between braced and unbraced
conditions (5 times each).
Threshold to detection of passive motion between
with and without functional knee brace (DonJoy).
Participants were placed blindfolded in a seated posi-
tion with approximately 110° of knee exion. Their
legs were moved into either exion or extension,
and they were instructed to depress a button once the
motion was detected in either direction.
A total of 24 repetitions was performed: Each leg was
tested 12 times. Braced and unbraced conditions were
tested 6 times each.
Ability to replicate target knee-joint angles between with
and without functional knee brace (DonJoy, Generation II,
and Lenox Hill Custom 2) in ACL-reconstructed individu-
Participants were seated blindfolded on computerized
dynamometer (Kin Com). They were instructed to extend
the knee to target knee-exion angles of 30–60° and
maintain the targeted angles for 3 s. Then they returned
the knee to the start position and, after a 5-s, were asked
to reproduce the previously attained target angle, stopping
when they perceived that the angle had been replicated.
This procedure was examined on the reconstructed knee
between braced and unbraced conditions (5 times each).
JSR Vol. 25, No. 2, 2016
Table 2 (continued)
Characteristic Wu et al
Risberg et al
Birmingham et al
measure Active knee-joint-angle reproduction (active joint
repositioning) Threshold to detection of passive motion (passive joint
repositioning) Average absolute difference scores (°) of knee-joint repli-
cation (active joint repositioning)
Results A signicant difference for the knee-joint-angle repo-
sitioning test. Post hoc contrasts revealed that under
both braced conditions there were smaller differences
in knee-joint angles than under the no-brace condi-
tion, but the 2 braced conditions were not different
from each other (no P value was reported).
ACL-reconstructed knee with functional knee braced
condition, 6.6 ± 3.3; ACL-reconstructed knee with
unbraced condition, 8.7 ± 4.2.
In the ACL-reconstructed group, there was no
improvement in the threshold to detection of passive
motion with braced compared with unbraced condi-
tion (no P value was reported).
ACL-reconstructed knee with braced condition, 0.99
± 0.58; ACL-reconstructed knee with unbraced condi-
tion, 1.06 ± 0.57.
The average absolute difference score (°) observed with
the functional brace was signicantly lower than without
the functional brace (P = .02).
ACL-reconstructed knee with braced condition, 2.8 ± 1.6;
ACL-reconstructed knee with unbraced condition, 3.5 ±
Conclusion The joint-position sense of the knee was improved
by wearing either a real brace or a mechanical pla-
cebo brace. The improved joint-position sense that
we observed in subjects with a brace may positively
affect the functional performance of these subjects.
No signicant differences in threshold to detection
of passive motion between the ACL-reconstructed
and healthy uninvolved knees or between the ACL-
reconstructed group and the healthy control group 1 y
or more postsurgery.
Application of a custom-t ACL functional knee brace
resulted in statistically signicant improvements in knee
proprioception using controlled laboratory situations char-
acterized by relative limited somatosensory input.
results The active joint-repositioning sense was superior in
braced conditions compared with the unbraced condi-
tion in an ACL-reconstructed population. The effect
size was .55 ± .06 (P = .023), and 95% condence
interval of the effect size did not cross zero. Thus,
the effect of the ACL functional brace on active
knee-joint-angle reproduction was greater than the
There is no difference in threshold to detect passive
motion between braced and unbraced conditions.
Effect size of the brace condition was .12 ± .08 (P =
Although statistical signicance was observed in knee
proprioception between braced and unbraced conditions,
effect size was .42 ± .06 (P = .079). Because the 95%
condence interval of the effect size crosses zero and the
P value exceeded .05, the results of this study need to be
interpreted with caution.
evidence 2b 2b 2b
Pedro scale 4/10 4/10 4/10
population The result of this study suggests that wearing a func-
tional knee brace enhances active joint-position sense
in ACL-reconstructed individuals.
The results did not support that use of a functional
ACL brace improves ability to detect passive motion
in individuals with ACL reconstruction.
This study indicated that wearing a functional ACL brace
could replicate knee-joint angles better than in nonbraced
conditions in an ACL-reconstructed population.
Abbreviation: ACL, anterior cruciate ligament.
194 Sugimoto et al
JSR Vol. 25, No. 2, 2016
sense, but perhaps a different population group for each
study might have inuenced the effect-size outcome.
The decreased joint-position sense in the ACL-recon-
structed population was also observed through balance
and postural-control measures.6–8 Lower balance-error
scores were found in the ACL-reconstructed population
than in a healthy control group.6 Another study reported
limited single-leg postural sway ability compared with
the noninvolved side and healthy control.7 The observed
joint-position-accuracy differences from the reviewed
studies ranged from 0.07° to 2.20°. Although the observed
joint-position-sense difference was small between braced
and nonbraced conditions, this difference may have had
a clinical implication. A prospective study8 that investi-
gated risk factors of subsequent ACL injury documented
that those who sustained a subsequent ACL injury after
ACL-reconstruction surgery demonstrated an overall
single-leg postural-stability score of 4.07° ± 2.06° at 7–8
months post-ACL-reconstruction follow-up visit, whereas
those who did not experience a subsequent ACL injury
scored 3.63° ± 1.58°. The mean difference between the
2 groups was 0.44°, providing a comparison with the
outcomes noted in this study; however, those measure-
ments were not specic to the knee joint. Furthermore,
all included studies1–3 tested knee-joint position sense
in open-kinetic-chain fashion, while other studies6–8
reported decits in balance and postural control with a
closed kinetic chain. Therefore, it is difcult to synthe-
size the results and provide a conclusion for the clinical
implication of a functional brace on joint-position sense.
It appears that physicians often prescribe a functional
knee brace to provide mechanical support and protect
the reconstructed ACL from retear for athletes returning
to sports. Our literature search did not nd a study that
compared subsequent ACL-tear incidence rates between
those who wore an ACL functional brace and those who
did not. The current project focused on the effect of a
functional knee brace on joint-position sense. However,
to justify the prescription of an ACL functional knee
brace, further evidence is needed to document a pro-
spective effect of bracing for reinjury. Although denite
challenges such as a long-term follow-up and adequate
sample sizes are expected, further studies are clearly
warranted to determine the prophylactic effectiveness of
ACL functional braces on a subsequent tear, mechanical
support, and joint-position sense.
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bracing on the sensorimotor function of subjects with
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2. Risberg MA, Beynnon BD, Peura GD, et al. Proprioception
after anterior cruciate ligament reconstruction with and
without bracing. Knee Surg Sports Traumatol Arthrosc.
1999;7(5):303–309. PubMed doi:10.1007/s001670050168
3. Birmingham TB, Kramer JF, Kirkley A, et al. Knee bracing
after ACL reconstruction: effects on postural control and
proprioception. Med Sci Sports Exerc. 2001;33(8):1253–
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4. Schutte MJ, Dabezies FJ, Zimny ML, et al. Neural anatomy
of the human anterior cruciate ligament. J Bone Joint Surg
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5. Schultz RA, Miller DC, Kerr CS, et al. Mechanoreceptors
in human cruciate ligaments: a histological study. J Bone
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6. Smith MD, Bell DR. Negative effects on postural control
after anterior cruciate ligament reconstruction as measured
by the Balance Error Scoring System. J Sport Rehabil.
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sway persists after anterior cruciate ligament reconstruc-
tion and return to sport. Gait Posture. 2013;38(1):136–140.
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Figure 1 — Effect-size Hedges g and 95% condence interval for the 3 included studies. All effect sizes were in favor of the treat-
ment; however, 2 of the 3 studies’ condence intervals crossed zero, indicating that these results should be viewed with caution.