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The Effectiveness of Functional Knee Brace on Joint Position Sense in Anterior Cruciate Ligament Reconstructed Individuals

Authors:
  • Waseda University / The Micheli Center for Sports Injury Prevention

Abstract and Figures

It is estimated that approximately 350,000 individuals undergo anterior cruciate ligament (ACL) reconstruction surgery in each year in the US. Although ACL reconstruction surgery and post-operative rehabilitation are successfully completed, deficits in postural control remain prevalent in ACL reconstructed individuals. Additionally, subsequent ACL re-tear incidence can be as high as 24%. In order to assist the lack of balance ability and reduce the risk of re-tear of the reconstructed ACL, physicians often provide a functional knee brace upon an athlete's return to physical activity. The common belief is that the functional knee brace provides mechanical support. Also, 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 experienced ACL reconstruction maintain optimum balance ability and decrease the future risk of ACL re-tear. However, it is not known whether the functional knee brace use enhances knee joint position sense in individuals with ACL reconstruction.
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190
CRITICALLY APPRAISED TOPIC
Journal of Sport Rehabilitation, 2016, 25, 190 -194
© 2016 Human Kinetics, Inc.
Journal of Sport Rehabilitation, 2016, 25, 190 -194
http://dx.doi.org/10.1123/jsr.2014-0226
© 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
at dai.sugimoto@childrens.harvard.edu.
The Effectiveness of a Functional Knee Brace
on Joint-Position Sense in Anterior Cruciate
Ligament–Reconstructed Individuals
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, decits 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 sufcient
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
Clinical Scenario
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, decits 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
ACL reconstruction.
Focused Clinical Question
Does the use of a functional brace improve knee-joint
position sense in individuals who have undergone ACL
reconstruction?
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-reconstructed individuals.
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 signicance for
the effect of a functional knee brace on joint-position
sense.
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
sense.
Search Strategy
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
• PubMed
• EBSCO
• MEDLINE
• Google Scholar
Additional resources obtained via review of refer-
ence lists and hand search
Inclusion and Exclusion Criteria
Inclusion 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
Exclusion Criteria
Studies that did not include individuals with ACL
reconstruction
• Studies that did not include a functional knee brace
• Studies that did not measure joint-position sense
Results of Search
Three relevant studies were identied and categorized
as shown in Table 1.
Best Evidence
The studies shown in Table 2 were identied 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
individuals.
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 signicant 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, Rufni 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 signicance (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
Level of
evidence Study
design Number
located Reference
2b Crossover
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
1
Risberg et al
2
Birmingham et al
3
Study design Single-blinded, crossover, laboratory study. Partici-
pants were asked to visit a laboratory and to repro-
duce specic knee-joint angles under 3 specic 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.
Intervention
investigated Reproducing knee-joint angle among functional knee
brace (DonJoy), mechanical placebo brace, and no
brace.
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
were recorded.
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-
als.
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).
(continued)
193
JSR Vol. 25, No. 2, 2016
Table 2 (continued)
Characteristic Wu et al
1
Risberg et al
2
Birmingham et al
3
Outcome
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 signicant 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 signicantly 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 ±
1.7.
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 signicant 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 signicant improvements in knee
proprioception using controlled laboratory situations char-
acterized by relative limited somatosensory input.
Interpretation of
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% condence
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
unbraced condition.
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 =
.668).
Although statistical signicance was observed in knee
proprioception between braced and unbraced conditions,
effect size was .42 ± .06 (P = .079). Because the 95%
condence interval of the effect size crosses zero and the
P value exceeded .05, the results of this study need to be
interpreted with caution.
Level of
evidence 2b 2b 2b
Pedro scale 4/10 4/10 4/10
Applicability to
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 inuenced 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 specic to the knee joint. Furthermore,
all included studies1–3 tested knee-joint position sense
in open-kinetic-chain fashion, while other studies6–8
reported decits in balance and postural control with a
closed kinetic chain. Therefore, it is difcult 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 denite
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.
References
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PubMed doi:10.1016/j.gaitpost.2012.11.001
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doi:10.1177/0363546510376053
Figure 1 — Effect-size Hedges g and 95% condence interval for the 3 included studies. All effect sizes were in favor of the treat-
ment; however, 2 of the 3 studies’ condence intervals crossed zero, indicating that these results should be viewed with caution.
... A recent systematic review reiterated the conflicting evidence of functional knee bracing on joint-position improvement after ACLR. 19 The authors further reiterated the importance of future studies needing to measure joint-position sense in closed-kinetic-chain fashion since ACL injury usually occurs under weight-bearing conditions. 19 In addition to potentially improving joint proprioception and postural control, functional bracing has been shown to reduce strain on the ACL or the ACL graft. ...
... 19 The authors further reiterated the importance of future studies needing to measure joint-position sense in closed-kinetic-chain fashion since ACL injury usually occurs under weight-bearing conditions. 19 In addition to potentially improving joint proprioception and postural control, functional bracing has been shown to reduce strain on the ACL or the ACL graft. A strain shielding effect with functional bracing may be advantageous to prevent ACL injuries. ...
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... In 2016, a systematic review published in the Journal of Sport Rehabilitation resulted in inconsistent evidence of functional knee bracing on joint-position improvement after ACLR even though physicians often provide a functional knee brace to the patients' returning to physical activity in order to assist their lack of balance ability and to reduce the risk of retear of the reconstructed ACL [53]. ...
... also stated that these effects rapidly diminished during physiologic stress loads. As we can see, more research is needed to provide evidence on the biomechanical effects of a functional knee brace that define its correct application[48,53]. ...
Thesis
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... While the timeline and specific goals during rehabilitation protocols may vary, it is currently believed that ACL reconstruction (ACLR) is the preferred surgical procedure necessary to return these athletes to their respective field of play [2]. There are approximately 350,000 ACLR procedures performed annually in the Unites States, and approximately one million worldwide [4,5]. However, the prevalence of ACL re-rupture rates in young and active adults is up to 20%, with 50% of them occurring during the first year after the primary ACLR procedure [6,7]. ...
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... Several researchers have reported that compression garments improve proprioception [23][24][25] and balance [26 29]. Zamporri J et al. reported that a compression garment can slightly alter the hip abduction range of motion only during landing from a drop vertical jump [30]. ...
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... It is estimated that as many as 350,000 anterior cruciate ligament (ACL) reconstructions (ACLRs) are performed every year in the United States. 7,12,18,37,44 Successful recovery after ACLR is based on several factors, including patient age, graft ligamentization, functional level before surgery, and participation in rehabilitation to restore knee strength and functional control. 12,25 Knee rehabilitation after ACLR can occur under the supervision of the physical therapist, 2 as a homerehabilitation program, 14,25 or via telehealth options. ...
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Background Physical therapy (PT) rehabilitation is critical to successful outcomes after anterior cruciate ligament reconstruction (ACLR). Later-stage rehabilitation, including sport-specific exercises, is increasingly recognized for restoring high-level knee function. However, supervised PT visits have historically been concentrated during the early stages of recovery after ACLR. Purpose/Hypothesis To assess the number and temporal utilization of PT visits after ACLR in a national cohort. We hypothesized that PT visits would be concentrated early in the postoperative period. Study Design Descriptive epidemiological study. Methods The Humana PearlDiver database was searched to identify patients who underwent ACLR between 2007 and 2017. Patients with additional structures treated were excluded. The mean ± SD, median and interquartile range (IQR), and range of number of PT visits for each patient were determined for the 52 weeks after ACLR. PT visits over time were also assessed in relation to patient age and sex. Results In total, 11,518 patients who underwent ACLR met the inclusion criteria; the mean age was 32.62 ± 13.70 years, and 42.7% were female patients. Of this study cohort, 10,381 (90.4%) had documented PT postoperatively; the range of PT visits was 0 to 121. On average, patients had 16.90 ± 10.60 PT visits (median [IQR], 16 [9-22]) after ACLR. Patients completed a mean of 52% of their PT visits in the first 6 weeks, 75% in the first 10 weeks, and 90% in the first 16 weeks after surgery. Patients aged 10 to 19 years had the highest number of PT visits (mean ± SD, 19.67 ± 12.09; median [IQR], 18 [12-25]), significantly greater than other age groups ( P < .001). Conclusion PT after ACLR is concentrated in the early postoperative period. Physicians, therapists, and patients may consider adjusting the limited access to PT to optimize patient recovery. Clinical Relevance As supervised PT visits may be limited, the appropriate temporal utilization of supervised PT visits must be maximized. Strategies to ensure sessions for later neuromuscular and activity-specific rehabilitation are needed.
... In the general population, the incidence of isolated ACL tears is around 68.6 per 100.000 person-years (Sanders et al., 2016), and subsequent retear incidence can be as high as 24% (Sugimoto, LeBlanc, Wooley, Micheli, & Kramer., 2016). Functional limitations were observed 12 years after the ACL injury (Lohmander, € Ostenberg, Englund, & Roos, 2004) therefore, a good rehabilitation process and functional examination is of the utmost importance to prevent retears and guarantee an adequate return to activity and pre-injury level of activity (Grinsven, van Cingel, Holla, & van Loon, 2010;Herrington, Myer, & Horsley, 2013). ...
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Objective: To identify the outcomes of physical function, physical fitness, training, and cuff parameters, used in BFRT in ACL rehabilitation. Methods: This scoping review was initiated on April 25th, 2020, according to the PRISMA Extension for Scoping Reviews (PRISMA-ScR). Relevant literature was identified searching three main concepts: BFRT, rehabilitation and ACL injury on MEDLINE (PubMed), CENTRAL of Cochrane Library, Web of Science and PEDro. Studies looking at adults with a primary ACL injury undergoing conservative or pre/post-surgery rehabilitation with BFR or BFRT, with physical fitness and physical function as outcomes or other physical outcomes were included. Results: Sixty-eight articles were identified and six were included. One article was added through backward tracking. All studies used BFRT in the ACL injury surgical rehabilitation. Most studies evaluated physical fitness (muscular strength and volume) however, physical function was not considered a primary outcome. Training and cuff parameters were heterogeneously prescribed. Conclusion: The existing evidence is not enough to draw definitive conclusions due to the heterogenous reported outcomes and parameters. Future investigation with standardized outcome measures and specific protocols are needed to draw conclusions on patients' physical function, so BFRT can be used more effectively in clinical rehabilitation practice.
... Periodization can be accomplished by manipulating sets, repetitions, exercise order, number of exercises, resistance, rest periods, type of muscle contraction, and training frequency, thereby providing numerous periodization programs. Manipulating variables is arguably the greatest challenge that coaches face, for example, when designing and modifying resistance training programs [17]. ...
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Periodization should be considered not only for athletic performance but also for rehabilitation of anterior cruciate ligament injury. • Anterior cruciate ligament injury is not just a local mechanical trauma, but its effects extend to the central nervous system as well. • Rehabilitation planned according to the periodization concepts should allow better integration of the needs of the patients to return to sport, using concepts which will be easily integrated with the sports and strength and conditioning coaches to ultimately benefit the athlete and prevent reinjury. Abstract More than 250,000 anterior cruciate ligament (ACL) injuries occur each year in the USA, and approximately 65% of these injuries undergo reconstructive surgery. Appropriate rehabilitation after ACL reconstruction can yield predictably good outcomes, with return to previous levels of activity and high knee function. At present, periodization is used at all levels of sports training. Whether conceptualized and directed by coaches, or by athletes themselves, competitors structure their training in a cyclic fashion, enabling athletes to best realize their performance goals. In practical application, sport physical therapists use periodization: postoperative "protocols" serve as rudimentary forms of periodization, al-beit implemented over shorter time frames than that typically employed in preparation for competition. An ACL injury should not be considered a "simple" musculoskeletal pathology with only local mechanical or motor dysfunctions.
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Objectives We aimed to assess the test-retest reliability of a supine and standing knee joint position sense (JPS) test, respectively, and whether they discriminate knees with anterior cruciate ligament (ACL) injury from asymptomatic knees. Design Repeated measures and cross-sectional. Setting Research laboratory. Participants For test-retest reliability, 24 persons with asymptomatic knees. For discriminative analysis: 1) ACLR - 18 persons on average 23 months after unilateral ACL reconstruction, 2) CTRL - 23 less-active persons, and 3) ATHL - 21 activity level-matched athletes. Main Outcome Measures Absolute error (AE) and variable error (VE). Results Test-retest reliability was generally highest for AE of the standing test (ICC 0.64-0.91). Errors were less for the standing compared to the supine test across groups. CTRL had greater knee JPS AE (P = 0.005) and VE (P = 0.040) than ACLR. ACLR knees showed greater VE compared to the contralateral non-injured knees for both tests (P = 0.032), albeit with a small effect size (ηp² = 0.244). Conclusions: Our standing test was more reliable and elicited lesser errors than our supine test. Less-active controls, rather than ACLR, produced significantly greater errors. Activity level may be a more predominant factor than ACLR for knee JPS ∼2 years post-reconstruction.
Article
Purpose The current study investigates the information quality available on YouTube regarding rehabilitation and return to sport (RTS) after ACL reconstruction (ACLR). Methods Using an Onion Router software and predefined search terms, 140 YouTube videos regarding rehabilitation and RTS after ACLR were systematically included. Three scoring systems were used to analyze the included videos: (1) Journal of the American Medical Association (JAMA) benchmark criteria; (2) Global Quality Score (GQS); (3) a self- developed score for ‘rehabilitation after ACLR and RTS after ACLR’, following AAOS guidelines and current evidence. Results The vast majority of the included videos offered poor information quality, reliability and accuracy. Videos that were uploaded by medical trained professionals showed a significantly higher information quality (Rehab: JAMA: p = .006; GQS: p < .001; ‘Rehab- Score”: p = .001; RTS: JAMA: p < .001; GQS: p < .001; ‘RTS- Score’: p < .001) compared to commercial videos or personal testimony videos. Multivariate linear regression also revealed medical trained professionals as significant predictor for a higher information quality (Rehab: JAMA: β = .496, p < .001, GQS: β = 1.3, p < .001, ‘Rehab- Score’ β = 3.7, p < .001; RTS: JAMA: β= .754, p < .001; GQS: β = 1.3, p < .001; ‘RTS- Score’: β = 5.3, p < .001). Conclusions The average information quality, reliability and accuracy of YouTube videos regarding rehabilitation and return to sport after ACL reconstruction is poor. Information quality of related YouTube videos from medical trained professionals was significantly higher compared to commercial videos or personal testimony videos. Clinical Relevance Current YouTube videos regarding rehabilitation and return to sport after ACL reconstruction do not meet the necessary quality standards. Physicians should also be able to provide alternative sources of high-quality information.
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Context Anterior cruciate ligament (ACL) reconstruction is the standard of care for individuals with ACL rupture. Balance deficits have been observed in patients with ACL reconstruction (ACLR) using advanced posturography, which is the current gold standard. It is unclear if postural-control deficits exist when assessed by the Balance Error Scoring System (BESS), which is a clinical assessment of balance. Objective The purpose of this study is to determine if postural-control deficits are present in individuals with ACLR as measured by the BESS. Participants Thirty participants were included in this study. Fifteen had a history of unilateral ACLR and were compared with 15 matched controls. Interventions The BESS consists of 3 stances (double-limb, single-limb, and tandem) on 2 surfaces (firm and foam). Participants begin in each stance with hands on their hips and eyes closed while trying to stand as still as possible for 20 s. Main Outcome Measures Each participant performed 3 trials of each stance (18 total), and errors were assessed during each trial and summed to create a total score. Results We observed a significant group × stance interaction ( P = .004) and a significant main effect for stance ( P < .001). Post hoc analysis revealed that the ACLR group had worse balance on the single-leg foam stance than did controls. Finally, the reconstructed group had more errors when total BESS score was examined ( P = .02). Conclusions Balance deficits exist in individuals with ACLR as measured by the BESS. Total BESS score was different between groups. The only condition that differed between groups was the single-leg stance on the unstable foam surface.
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Athletes who return to sport participation after anterior cruciate ligament reconstruction (ACLR) have a higher risk of a second anterior cruciate ligament injury (either reinjury or contralateral injury) compared with non-anterior cruciate ligament-injured athletes. Prospective measures of neuromuscular control and postural stability after ACLR will predict relative increased risk for a second anterior cruciate ligament injury. Cohort study (prognosis); Level of evidence, 2. Fifty-six athletes underwent a prospective biomechanical screening after ACLR using 3-dimensional motion analysis during a drop vertical jump maneuver and postural stability assessment before return to pivoting and cutting sports. After the initial test session, each subject was followed for 12 months for occurrence of a second anterior cruciate ligament injury. Lower extremity joint kinematics, kinetics, and postural stability were assessed and analyzed. Analysis of variance and logistic regression were used to identify predictors of a second anterior cruciate ligament injury. Thirteen athletes suffered a subsequent second anterior cruciate ligament injury. Transverse plane hip kinetics and frontal plane knee kinematics during landing, sagittal plane knee moments at landing, and deficits in postural stability predicted a second injury in this population (C statistic = 0.94) with excellent sensitivity (0.92) and specificity (0.88). Specific predictive parameters included an increase in total frontal plane (valgus) movement, greater asymmetry in internal knee extensor moment at initial contact, and a deficit in single-leg postural stability of the involved limb, as measured by the Biodex stability system. Hip rotation moment independently predicted second anterior cruciate ligament injury (C = 0.81) with high sensitivity (0.77) and specificity (0.81). Altered neuromuscular control of the hip and knee during a dynamic landing task and postural stability deficits after ACLR are predictors of a second anterior cruciate ligament injury after an athlete is released to return to sport.
Article
Postural sway is defined as the movement of a body's center of mass within the base of support to maintain postural equilibrium. Deficits in postural sway are present after ACL injury; however, current evidence linking it to future injury risk is unclear. The purpose of this study was to determine if postural sway deficits persist after ACL reconstruction (ACLR). The hypothesis tested was that after ACLR, patients who return to sport (RTS) would demonstrate differences in postural sway compared to control (CTRL) subjects. Fifty-six subjects with unilateral ACLR released to RTS, and 42 uninjured CTRL subjects participated. Dynamic postural sway was assessed and 3-way (2×2×2) ANOVA was used to analyze the variables. A side×group×sex (p=0.044) interaction in postural sway was observed. A side×group analysis also revealed an interaction (p=0.04) however, no effect of sex was observed (p=0.23). Analysis within the ACLR cohort showed less (p=0.001) postural sway on the involved side (1.82±0.84°) versus the uninvolved side (2.07±0.96°). No side-to-side differences (p=0.73) were observed in the CTRL group. The involved limb of subjects after ACLR demonstrated the least postural sway. In conclusion, these findings indicate that dynamic postural sway may be significantly altered in a population of athletes after ACLR and RTS compared to CTRL subjects. Further investigation is needed to determine if deficits in postural sway can be used as an effective criterion to assist in the decision to safely RTS after ACLR.
Article
The histology of the anterior cruciate ligament was studied by a modified technique of the Gairns gold chloride stain for neural elements. Three morphological types of mechanoreceptors and free nerve-endings were identified: two of the slow-adapting Ruffini type and the third, a rapidly adapting Pacinian corpuscle. Rapidly adapting receptors signal motion and slow-adapting receptors subserve speed and acceleration. Free nerve-endings, which are responsible for pain, were also identified within the ligament. These neural elements comprise 1 per cent of the area of the anterior cruciate ligament.
Article
We obtained human cruciate ligaments at the time of total knee replacement and from autopsy and amputation specimens, and examined histological sections of the ligaments for the presence of mechanoreceptors using the Bodian, Bielschowsky, and Ranvier gold-chloride stains for axons and nerve-endings. The cruciate ligaments obtained at the time of total knee replacement were too distorted by disease processes to be of use. The autopsy and amputation specimens, however, contained fusiform mechanoreceptor structures measuring 200 by seventy-five micrometers, with a single axon exiting from the capsule of the receptor. One to three receptors were found at the surface of each ligament beneath the synovial membrane, and were absent from the joint capsules and menisci. Morphologically the receptors resembled Golgi tendon organs, and it seems likely that they provide proprioceptive information and contribute to reflexes inhibiting injurious movements of the knee. This is the first histological demonstration of mechanoreceptors in human cruciate ligaments.
Article
In this investigation we evaluated the effect of ACL reconstruction and functional knee bracing on knee proprioception. Twenty subjects who experienced acute ACL disruption and underwent reconstruction with a bone-patellar tendon-bone graft participated in a controlled rehabilitation program and were studied at a mean follow-up of 2 years. A control group of ten subjects were also studied. In both groups proprioception was evaluated by measuring the threshold to detection of passive motion (TDPM) with the knee at 15 degrees of flexion with and without a functional knee brace applied. The Knee Osteoarthritis Outcome Score, Cincinnati knee score, and two functional knee tests were also used as outcome measurements. Anterior-posterior displacement of the tibia relative to the femur was evaluated with the KT-1000 arthrometer. There were no significant differences in TDPM between the ACL-reconstructed and contralateral knees, or between the ACL reconstructed group and the healthy control group. Bracing did not produce a significant change in the TDPM for the ACL-reconstructed group or for the control group. There were low to moderate correlations between TDPM and the other outcome measurements. This study indicates that there is no significant differences in proprioception between the ACL-reconstructed knee and the contralateral uninvolved knee 1 year or more after surgery. Functional knee bracing does not seem to improve proprioception in patients who have undergone ACL reconstruction and been followed up on average 2 years after surgery.
Article
To evaluate the effects an anterior cruciate ligament (ACL) brace has on various measures of knee proprioception and postural control. Thirty subjects (mean age 27 +/- 11 yr) having undergone unilateral ACL reconstruction were tested with and without wearing their own custom-fit brace on their involved limb. Proprioception was assessed using joint angle replication tests completed on an isokinetic dynamometer. Postural control was assessed using a series of single-limb standing balance tests completed on a force platform. The balance tests included: 1) standing on the stable platform with eyes open, 2) standing on a foam mat placed over the platform with eyes open, 3) standing on the platform with eyes closed, and 4) standing on the platform after landing from a maximal single-limb forward hop. The brace provided a small but statistically significant improvement in proprioception (mean reduction in error scores between target and reproduced angles = 0.64 +/- 1.4 degrees, P = 0.02). For the postural control tests, there was a significant brace condition by test situation interaction (P = 0.02), with the brace providing a small but statistically significant improvement during the test completed on the stable platform with eyes open (mean reduction in center of pressure path length = 4.2 +/- 8.4 cm, P = 0.02) but not during the other more challenging test situations. Additional post hoc analyses indicated that the relationship between knee proprioception and postural control measures were low and not significant (r = 0.003 to 0.19, P > 0.32), consistent with the suggestion that changes in knee proprioception can occur in the absence of substantial changes in postural control. Also, standing balance tests that challenged the somatosensory contribution to postural control (i.e., those completed on foam, or with eyes closed) were significantly related to single-limb forward hop distances (r = -0.4, P < 0.05), whereas performance during the proprioception test was not (r = 0.1, P > 0.50). In general, bracing appears to improve performance during tasks characterized by relatively limited somatosensory input but not during tasks characterized by increased somatosenory input. The small magnitude of the improvements, coupled with their apparent lack of carry over to more difficult and functionally relevant tasks, questions the clinical benefit of the present effects of bracing.
Article
The sensorimotor performance of the knee joint in 31 subjects who had undergone unilateral anterior cruciate ligament reconstruction at least 5 months previously was tested under three bracing conditions, 1) the DonJoy Legend brace, 2) a mechanical placebo brace, and 3) no brace, in random order. The accuracy of the subjects' ability to reproduce specified knee joint angles was tested as well as the isokinetic performance of their knee muscles at 60 and 180 deg/sec. The results showed that subjects with the brace or placebo brace performed similarly in reproducing the knee joint positions, but both groups performed better than the subjects without a brace. Isokinetic tests revealed no difference among the three groups in extensor and flexor peak torque production at 60 deg/sec or total work done by the extensors and flexors at 60 and 180 deg/sec. These results suggest that knee bracing can improve the static proprioception of the knee joint, but not the muscle contractile function, in subjects with anterior cruciate ligament reconstruction under isokinetic testing conditions. The finding of similar performances for joint angle reproduction in the brace and placebo brace groups suggests that the apparent improvement in proprioception with knee bracing was not due to the mechanical restraining action of the brace.
Effects of knee bracing on the sensorimotor function of subjects with anterior cruciate ligament reconstruction
  • Gkh Wu
  • Mpt Phil
  • Gyf Ng
Wu GKH, Phil MPT, Ng GYF, et al. Effects of knee bracing on the sensorimotor function of subjects with anterior cruciate ligament reconstruction. Am J Sports Med. 2001;29(5):641–645. PubMed