Keywords
knee osteoarthritis - braces - walking - knee arthroplasty - varus - valgus
Osteoarthritis is a common condition with 18% of people over 45 years old seeking
treatment for osteoarthritis of the knee joint,[1] and 12% have symptoms associated with osteoarthritis aged 25 to 75 years.[2] Varus or valgus malalignment is a cause of the pathophysiology, specifically for
unicompartmental knee osteoarthritis. A varus alignment increases the mechanical load
and risk of medial compartmental osteoarthritis, whereas a valgus alignment affects
the lateral compartment.[2]
The National Institute for Clinical Excellence (NICE) state, in their 2014 guidelines,
that treatment for osteoarthritis should take a holistic approach.[3] This should include, at its simplest, patient education and nonpharmacological treatment
like exercise, weight loss, aids, and devices such as knee braces, insoles, and walking
sticks.[3] Surgical treatments are cost-effective treatments for osteoarthritis and include
total knee replacement, unicompartmental knee arthroplasty, and high tibial osteotomy.[4]
[5] However, waiting lists can be up to 8 months,[6] and there is evidence to suggest that these treatments are not suitable for younger
patients suffering from knee osteoarthritis.[7] This is because younger patients tend to have more active lifestyles which increases
the risk of any surgical arthroplasty loosening or wearing out.[7] This combined with their longer life expectancy means that they are much more likely
to require a revision,[7] especially considering revision rates after 5 years are 6% and 12% after 10 years.[8] Younger patient age groups are more likely to respond better and have improved knee
function after total knee replacement; however, a major concern is that they are much
more likely to be left dissatisfied with the outcome, especially considering one-fifth
of all patients have been reported to be unhappy with their knee after having surgery.[9]
NICE guidelines recommend the use of knee braces for the treatment of osteoarthritis,
as part of the nonpharmacological management.[3] Osteoarthritis Research Society International have produced guidelines which include
biomechanical interventions to treat patients with mild to moderate varus/valgus instability
to improve stability and reduce pain.[10] Knee bracing is also incorporated in the European League Against Rheumatism recommendations
in 2003, as part of the nonpharmacological management of osteoarthritis.[11]
Knee Bracing
There are different types of knee braces, which can be used to treat knee problems.
Depending on the pathology and diagnosis, different types of mechanical support are
required. For unicompartmental knee osteoarthritis, unloading type knee braces are
more appropriate to unload the affected compartment and realign the knee joint. Studies
into knee braces date back into the 20th century. Although the studies of Lindenfeld
et al,[12] in 1997, and Kirkley et al,[13] in 1999, are small, they found that valgus knee braces were able to reduce pain
and improve function. Also, Katsuragawa et al[14] demonstrated that valgus bracing in patients with medial compartmental osteoarthritis
can alter mechanical alignment and increase bone mineral density in the lateral side
of the femur and tibia.[14] This suggests there has been an unloading effect from the medial compartment because
of the knee brace, and the bone strengthened on the lateral side as it received more
load.[14]
Out of all the unloading type knee braces, the Unloader One® brace (Ossur) has the
most published evidence. It has a 3-point leverage system which is able to unload
the affected compartment and is recommended for mild to severe unicompartmental osteoarthritis.[15] The studies by Lindenfeld et al,[12] Kirkley et al[13] and Katsuragawa et al[14] showed that there is some evidence to support unloader knee braces published over
10 years ago. However, in the past 10 years people's lifestyles have changed and the
prevalence of osteoarthritis has increased. This along with the fact that surgical
techniques have improved and, as a result, expectations have changed, mean an up-to-date
review on the past 10 years is required.
The aim of this report was to review previous evidence for unloader knee braces and
provide an update on new evidence that has been published in the past 10 years to
collate our knowledge on this potential treatment for unicompartmental knee osteoarthritis.
Methods
A MEDLINE and EMBASE search was performed using search terms including knee, bracing,
osteoarthritis, unicompartment*, unloader, valgus, and varus. The search was limited
to the English language and the past 10 years. Papers had to be original research
published in peer-reviewed journals. Their focus had to be on the unloader knee brace
and specifically for their treatment in unicompartmental knee osteoarthritis. Articles
had to compare unloader braces to a control or other treatment, or look at a cohort
that was using unloader knee braces. One of the main outcomes had to be pain, function,
quality of life, knee adduction moments, biomechanics, and gait analysis. The papers
were narrowed down based on their titles, abstracts, and then after reading the whole
paper by D.M. and P.L. The references and related articles of the papers found were
screened for suitable articles. We did not include papers which looked at misalignment
after other orthopedic/surgical procedures such as anterior cruciate ligament (ACL)
reconstruction.
Results
The search produced 112 papers, which were narrowed down to 22 based on their titles.
Overall, 14 articles were looked at, including 2 papers from 2017. Each paper is presented
below and the summary of the evidence is presented in [Table 1].
Table 1
Summary of evidence
Study
|
Type of study
|
Model
|
Method
|
Results
|
Conclusion
|
Brouwer et al (2006)[16]
|
In vitro
|
Multicenter randomized controlled trial
|
Patients with unicompartmental osteoarthritis were split into two groups—conservative
treatment alone or conservative plus brace treatment. They were then assessed for
pain severity, knee function score, walking distance, and quality of life. Multilinear
regression models were used
|
117 patients were used and followed up at 12 mo. Brace treatment group outperformed
the conservative group in all outcomes. Those who responded better were varus patients,
severe osteoarthritis patients, secondary osteoarthritis patients, and < 60 y
|
Some beneficial effects seen due to knee brace treatment. Some patients did not comply
with the brace in the long term
|
Gaasbeek et al (2007)[17]
|
In vitro
|
Prospective cohort study
|
Patients with medial knee osteoarthritis were identified and were given a valgus knee
brace for 6 wk. At which point gait analysis and pain and function were assessed
|
There were improvements in pain and function after 6 wk and gait analysis showed a
reduction in varus moment about the knee and this effect was increased in patients
with greater deformity
|
This study identified certain effects knee braces have in a patient's gait. These
may have clinical relevance in the future
|
Ramsey et al (2007)[18]
|
In vitro
|
Prospective cohort study
|
Patients were recruited based on a criteria, which included them having medial knee
osteoarthritis. Gait analysis was performed without a brace, with a brace in neutral
alignment and with the brace in 4° valgus. Pain, instability, and function were assessed
using questionnaires
|
16 patients were recruited. Scores for pain, function, and instability were worst
without a brace, but best with the brace in neutral alignment. Cocontractions of paired
muscles were reduced with the knee braced, more so with the brace in neutral alignment
|
Neutral alignment knee braces perform just as well as valgus aligned knee braces in
the treatment of medial knee osteoarthritis. This is in regard to reducing pain, disability
and cocontraction
|
Fantini Pagani et al (2010)[19]
|
In vitro
|
Prospective cohort study
|
Healthy patients with varus alignment were recruited. Gait analysis of patients were
measured with and without a valgus knee brace, in neutral, 4° valgus, and 8° valgus
|
During walking, there was a significant reduction in knee adduction moments and adduction
angular impulse with the brace in 4° valgus and 8° valgus. However, more significant
differences were only found when the brace was in 8° valgus when running
|
Knee braces were effective at reducing knee adduction moments during walking and running,
which should aid slowing the progression of osteoarthritis
|
Schmalz et al (2010)[20]
|
In vitro
|
Prospective cohort study
|
Patients were recruited if they had medial knee osteoarthritis. After the subjects
had worn the brace for 4 wk, gait analysis and valgus moments of the knee were assessed
|
There was a reduction in the valgus moment to 10% of it without the brace, which may
explain the pain relief experienced by patients. There was a reduction in gait asymmetry
when patients were using the brace
|
Bracing reduced valgus moments around the knee which unloads the medial compartment.
This leads to reduction in pain and increase in function
|
van Raaij et al (2010)[21]
|
In vitro
|
Randomized controlled trial
|
Patients with mild medial symptomatic knee osteoarthritis were recruited and randomized
into a lateral wedge foot insole group or a valgus brace group. They were assessed
at 6 mo on pain severity and function
|
There were no differences in the improvements in pain and severity after 6 mo in either
treatment group. The insole group had better compliance
|
Lateral wedge foot insoles may be an alternative to valgus bracing to treat medial
knee osteoarthritis
|
Briggs et al (2012)[22]
|
In vitro
|
Prospective cohort study
|
Patients were recruited who had been diagnosed with unicompartmental knee osteoarthritis.
Patients were instructed to complete the SF-12, WOMAC, and Tegner activity questionnaires,
at enrolment, 3 wk, 6 wk, and 6 mo. They also completed an expectation questionnaire
at enrolment
|
39 patients were found, all were prescribed an unloader brace. There was a significant
improvement in quality of life, pain, stiffness, and function. Important expectations
of these patients included return to recreational sports, improving ability to walk,
and pain relief
|
Unloader braces can be effective treatments to increase function of the knee by reducing
pain. This leads to an increase in overall health. Patients' expectations can be met
using the brace
|
Wilson et al (2011)[23]
|
In vitro
|
Retrospective study
|
30 patients with unicompartmental knee osteoarthritis were treated with knee braces
and followed up at an average of 2.7 y and then again at 11.2 y
|
24 out of the 30 patients were available to contact. Five patients died but they spoke
to the family relatives of these patients. At 2.7 y, 41% were still using the brace,
35% stopped using it, and 24% had undergone arthroplasty. At the second follow-up,
59% had undergone arthroplasty and none of the patients were using the brace
|
They found the unloader to be effective in the short term but for the long term, most
patients preferred to undergo arthroplasty surgery
|
Larsen et al (2013)[24]
|
Clinical
|
Prospective cohort study
|
Patients were recruited with varying degrees of knee osteoarthritis and were tested
on walking and sit-to-stand activities after 2 mo of treatment with a knee brace.
Pain was also assessed
|
There were no differences in the improvement of pain between the different grades
of osteoarthritis. Sit-to-stand activities were performed better at 1 mo in moderate
osteoarthritis and at 2 mo by milder osteoarthritis grades
|
This study provides data which may help refine the optimum use of knee braces
|
Niazi et al (2013)[25]
|
Clinical
|
Prospective cohort study
|
Patients with symptomatic medial osteoarthritis were identified and were treated with
the unloader brace for 6 mo before being assessed for pain, knee function, walking
distance, and alignment on X-ray. They were also assessed at baseline
|
80 patients were enrolled. After 6 mo, there were statistically significant changes
in pain and walking distance by using the unloader brace compared with baseline scores
|
Unloader braces were effective at managing pain relief and improving function in knee
osteoarthritis
|
Iqbal (2014)[26]
|
Clinical
|
Randomized controlled trial
|
Patients with symptomatic medial knee osteoarthritis were enrolled. Half were given
a knee brace; the other half were given a lateral wedge foot insole. Patients after
6 mo were assessed on pain and function
|
Pain and walking distance reduced in both treatment groups; however, the unloader
brace group outperformed the foot orthotic group. There were slightly more complications
with the knee brace
|
The unloader knee brace is more effective at treating medial knee osteoarthritis than
lateral wedge foot insoles
|
Dessery et al (2014)[27]
|
In vitro
|
Prospective cohort trial
|
Patients with medial knee osteoarthritis were asked to wear three different braces—a
valgus brace, a valgus and external rotation unloader brace, and an ACL brace. Pain
relief, comfort, and gait analysis were performed with each brace
|
All braces alleviated knee pain but the unloader and ACL brace allowed for a reduction
in peak adduction moment which was significant. There was a decrease in gait velocity
with the valgus brace. Patients were less inclined to wear the braces due their bulkiness,
although the unloader was the most comfortable and had the best compliance rate
|
When assessing for pain reduction, discomfort, and knee adduction moment, there was
little difference between the knee braces
|
Moyer et al (2017)[28]
|
In vitro
|
Prospective cohort trial
|
Patients with medial osteoarthritis were given a valgus brace and lateral wedge foot
orthotic. Gait analysis was performed on these patients with no brace or orthotic;
with just the brace; with just the orthotic; and then with the orthotic and brace
together. During this analysis patients were assessed to walk up and down stairs
|
There was a reduction in knee adduction moments in all intervention groups during
stair descent, more so in the brace and insole group, but no difference in stair ascent.
There were less gait decompensations with the combined intervention group too
|
This suggests that using knee braces and foot orthotics together to correct gait in
knee osteoarthritic patients is more effective than using just one but no conclusions
can be made as to whether these interventions shift biomechanical load
|
Lee et al (2017)[1]
|
Clinical
|
Prospective cohort trial
|
8 y of data was collected from patients with unicompartmental osteoarthritis. A quality
of life questionnaire was collected at enrolment and while wearing the brace. Cost
and quality-adjusted life years (QALYs) were then compared with total knee replacement
with 8 y of follow-up
|
There was an average increase of 0.42 after wearing the brace for 26.1 mo in the quality
of life questionnaire. Compared with no treatment, the unloader was cost effective
at 4 mo or more. At 8 y, the unloader brace had QALY gains of 0.43 and was a lot more
cost effective than total knee replacements by £6,467
|
Unloader knee braces are cost effective for unicompartmental osteoarthritis management.
The brace could potentially delay or even replace surgery
|
Abbreviations: SF-12, 12-Item Short Form Health Survey; WOMAC, Western Ontario and
McMaster Universities Osteoarthritis Index.
Previous Clinical Studies
Previous Clinical Studies
In 2006, Brouwer et al[16] conducted a randomized controlled trial (RCT) involving 117 patients and reviewed
them at 3, 6, and 12 months. Half of the patients were given just conservative management,
and the other half knee bracing and conservative management; and they found improvements
in knee function and pain in the group using the brace.[16] This study is limited by the fact that patients were not followed up for long term
and compliance issues (some patients did not continue to use the brace for more than
3 months).[16] It did see better results in the patients who had varus alignment and in patients
under 60 years of age, and therefore they state unloader braces could potentially
be used to avoid or delay surgery in the younger patient.[16]
Gaasbeek et al[17] in 2007 looked at 15 patients with medial osteoarthritis. The braces were worn for
7 days a week for 6 weeks.[17] They found a decrease in symptoms, as judged by the Western Ontario and McMaster
Universities Osteoarthritis Index (WOMAC) scoring system, and a decrease in pain during
walking.[17] They also generally found a reduction in peak varus moment around the knee during
gait analysis and this effect was more pronounced in patients with worse alignment.[17]
Ramsey et al[18] analyzed 16 patients' gaits, with medial knee osteoarthritis, while wearing knee
braces. They also looked at the electromyography of muscles around the knee to evaluate
the muscle co-contractions (vastus lateralis with lateral hamstrings and vastus medialis
with medial hamstrings).[18] They tested patients when unbraced as a baseline, then with bracing to neutral alignment
(after wearing for 2 weeks) and with bracing to 4° of valgus (again after wearing
for 2 weeks but with a 2-week unbraced period before).[18] Pain and function were also assessed using questionnaires. Nine of the 16 patients
reported instability and pain before the study, but this dropped to one after wearing
the brace for 2 weeks in neutral alignment.[18] After the washout period and then wearing the brace for 2 weeks in valgus alignment,
6 reported instability.[18] Knee adduction moments during the gait analysis was reduced in both types of bracing
and muscle co-contractions significantly improved in both types, but more so when
valgus bracing was adopted.[18] Conclusions that can be drawn from this include that unloader braces are effective
at alleviating pain, but also that using these braces to align the knee to neutral
rather than overcompensating into valgus alignment, may be just as effective.[18]
A study performed by Fantini Pagani et al[19] in 2010, was fairly similar to Ramsey et al's[18] study. Fantini Pagani et al[19] found 16 male patients with varus knee alignment and analyzed their gait during
walking and running with a valgus brace. The brace was adjusted to neutral, 4° valgus
and 8° valgus.[19] They found that the knee brace took away some of the load (due to a reduction in
the adduction moments of the knee) during the stance phase of walking and running.[19]
Again, Schmalz et al[20] looked at gait analysis in patients with medial osteoarthritis. Schmalz et al[20] had a cohort of 16 patients, all of whom had worn the brace for 4 weeks. During
walking, their findings agreed with those of Ramsey et al[18] and Fantini Pagani et al[19] that there is a reduction in knee adduction moments caused by wearing the brace
and this, they suggested, could be the mechanism which led to a reduction in symptoms
in these patient. They also found that the walking speed increased significantly in
their cohort, which again could be due to pain relief.
An RCT by van Raaij et al[21] conducted in 2010 randomized 91 patients with medial knee osteoarthritis, into either
a valgus knee brace treatment group or a 10-mm lateral-wedge shoe insole group. Their
outcomes included pain, severity, and function.[21] Patients were asked to use the treatment for 6 hours a day every day.[21] After 6 months, there were improvements in pain, severity, and function of the knee
in both treatment groups and both performed equally, compared with the baseline data.[21] This paper shows knee braces to be effective in treating some of the symptoms of
knee osteoarthritis and improving function.[21] It states that insole wedges could be used as another effective treatment for this
condition.[21] Unfortunately, they did not use a control group (no treatment or conservative treatment)
which would have allowed assessment of how much each treatment improved pain and function.[21]
In 2012, a study was performed looking into the change in quality of life and knee
function, if any, before and after 39 patients were treated with a knee brace.[22] Briggs et al[22] followed up their cohort at 3 weeks, 6 weeks, and 6 months.[22] They found an improvement in quality of life, pain, stiffness, and function when
patients were given a knee brace. Patients found that they were able to do more recreational
activity while being treated with an unloader brace.[22] Briggs et al[22] also looked at the expectations of patients suffering from knee osteoarthritis,
as well as investigating unloader knee braces. They identified that two outcomes patients
expected as a result of treatment—return to recreational sports and pain reduction
(over half of these patients expected all the pain to cease).[22] Other important things were reduction in knee stiffness, knee swelling, and improvement
in walking.[22] They summarized patients' expectations as having confidence in the knee, avoiding
further deterioration in the future, and maintaining general health.[22]
While most of these studies were fairly short term, one of the first long-term studies
on knee braces was conducted by Wilson et al[23] in 2011. They only looked at 30 patients, and followed their progress at an average
of 2.7 and 11.2 years.[23] The majority of patients reported pain relief, increased function, decreased stiffness,
and swelling after exercise and 41% were still using the brace at the first follow-up.[23] However, at 11.2 years, none of the patients were using the knee brace and over
half had had a total knee replacement.[23] Of the patients who had a total knee replacement, on average there was 3.9 years
between the initial assessment for a knee brace and them having the surgery.[23] They concluded that while the brace, in the short term, was an effective treatment,
patient's preferred choice was to have a knee replacement instead of continuing with
the brace for long term.[23]
In 2013, Larsen et al[24] conducted a prospective study which looked into the effect valgus knee braces have
on activities of daily living with their primary focus being walking and sit-to-stand/stand-to-sit
activities. Their patients had been wearing the brace for 2 months during the study.[24] In patients with low and moderate knee osteoarthritis, they found an increase in
activity while using the brace.[24] This was coupled with a decrease in pain too, which may have contributed to the
increase in activity level.[24] With regards to walking, their patients had a nonsignificant improvement in knee
adduction but they found that they were able to push off with more power.[24] This suggests that the brace, by redistributing the loading forces in the knee,
is aiding the strengthening of muscles in the leg.[24] This then leads to increased function and activity levels found in this study, including
improvements in sit-to-stand and stand-to-sit exercises.[24] Overall, they could only conclude that valgus bracing in medial knee osteoarthritis
could lead to short-term improvements in function of the knee in patients with mild
to moderate osteoarthritis.[24] Unfortunately, they did not look at patients with severe osteoarthritis and their
study only lasted 2 months, so no long term conclusions could be drawn from this;
however, they did state that the brace has the potential to delay to avoid surgical
intervention in these patients.[24]
Niazi et al[25] in 2013 conducted a case series study to assess any change in pain and function
in the knee in 80 patients with medial knee osteoarthritis using an unloader knee
brace. Their outcomes included pain severity, walking distance, and knee function
scores (using WOMAC scoring system).[25] Four patients were lost to follow-up.[25] Pain severity and walking distance significantly improved in these patients after
6 months of brace use and they also found that patients used less pain killers as
a result and knee function scores improved.[25] They stated that unloader bracing is an effective treatment for unicompartmental
knee osteoarthritis and can be used in patients who are less keen on or contraindicated
against surgery.[25] Niazi et al[25] concluded that it should be considered in all patients with this condition along
with standard medical treatment, and surgical intervention should not be considered
unless a patient has tried to use an unloader brace.
Iqbal[26] (part of a similar team to Niazi et al[25]) conducted an RCT comparing unloader knee braces with lateral wedged insoles,[26] similar to van Raaij et al.[21] In total, 120 patients were involved in the study by Iqbal.[26] Patients were instructed to wear the brace for 3 to 4 hours for the first week then
as long as they could during the day after that.[26] Their main outcomes, like their previous paper, was pain and walking distance (using
the second section of the Lequesne scale).[26] Four patients using insoles and two using braces were lost to follow-up and three
in the insole group and two in the brace group changed treatment because of lack of
symptomatic relief or complications.[26] The baseline differences in pain and severity between the two groups were insignificant;
however, after 6 months of treatment, the brace group's pain score was 3.97 and the
insole group's score was 4.53.[26] For walking distance, the brace group was also better with a score of 1.93 on the
Lequesne scale—an improvement of 0.43 compared with the lateral wedge insole group,
and there was an improvement in activity levels in the braced group; these differences
between the two groups were statistically significant.[26] It was concluded by Iqbal[26] that despite improvements in both groups, the unloader knee brace outperformed lateral
wedge insoles in all outcomes; however, there were a few more complications associated
with bracing; five patients experienced leg swelling.
Dessery et al[27] looked at 24 patients with medial knee osteoarthritis, each tried three different
knee braces for 2 weeks before assessment. They assessed pain relief, comfort, and
gait analysis.[27] The three braces in question were a valgus brace, an unloader brace with valgus
and external rotation functions, and a functional knee brace for ligament injuries
(ACL-brace).[27] All three braces alleviated pain immediately but the unloader brace and ACL brace
allowed for a significant decrease in load during the stance phase.[27] The valgus brace saw a decrease in gait velocity.[27] They only show pain relief differences from the braces in the short term and focused
more on the biomechanical analysis of the gait.[27] They also reported patients were less inclined to wear the braces for long periods
due to their bulkiness but the unloader brace was the most comfortable of the three.[27] In conclusion, they stated that all three braces were similar in terms of pain and
function improvements.[27]
Most Recent Research in 2017
Most Recent Research in 2017
Moyer et al[28] looked at 35 patients' gait during stair ascent and descent. At first, the patients
were tested with no mechanical aids, then with just a custom-fit valgus knee brace,
then a lateral wedge foot insole, and then both the brace and foot insole.[28] During stair descent, there was a reduction in knee adduction moments in all intervention
groups compared with the control, more so in the brace and insole group, but no difference
in stair ascent.[28] Gait speeds were similar across all conditions during both ascent and descent.[28] Overall, there were fewer gait compensations during descent compared with ascent.[28] In summary, the knee brace and lateral wedge insole had the best biomechanical effect
on gait during stair descent and almost half the patients (17 patients) preferred
this treatment, although it did not have the same effect on stair ascent.[28] This study again looked at a very little number of patients and did not look at
patients over the long term which makes it hard to clinically relate this study to
practise.[28]
A prospective study conducted by Lee et al[1] followed patients up for over 8 years while they were treated with the Ossur Unloader
One knee brace. It is one of the first studies to provide long-term evidence about
unloader knee brace use and followed 63 patients with end-stage knee osteoarthritis
(irrespective of the affected compartment)—one patient withdrew.[1] Patients on average wore the brace for 26 months, with some opting out of surgery
and instead preferring to use the knee brace for long term.[1] At the final follow-up, 40% of patients did not require surgery; excluding these,
of the remaining 38, the average brace use was 8.6 months.[1] Their analysis showed that if patients were able to tolerate the unloader brace
for 2 years their chances of having surgery decreased significantly; in fact, in the
study, anyone who wore the brace for more than 2 years, did not go on to have surgery.[1] Wearing the brace for 6 months halved the chance of a patient having to need surgery
compared with those who wore the brace for 3 months or less.[1] Their results suggested that unloader knee braces are cost effective in patients
who are awaiting surgery.[1]
Analysis of their results showed that there was no difference in how long patients
wore the brace, depending on certain patient demographics including gender, age, body
mass index (BMI), socioeconomic group, leg, or compartment.[1] So, potentially all patients could benefit from unloader braces if they have unicompartmental
osteoarthritis. Overall, Lee et al[1] showed the unloader knee brace to be a cost-effective management option for unicompartmental
osteoarthritis, as it can delay or reduce the frequency of surgery.
A summary of this evidence can be found in [Table 1].
Discussion
The aim of this review was to give an update on the literature in the past 10 years
on unloader braces including the more recent articles in 2017. We presented 14 pieces
of original research. Lee et al's[1] study was the only piece that looked at a large cohort of patients over the long
term to investigate unloader knee brace use. They found that knee braces were cost
effective but importantly could replace the need for surgery, if not delay it over
8 years. The other long-term study, by Wilson et al,[23] was retrospective and only used 30 patients, so while their results are important,
their conclusions are not as strong as Lee et al's.[1]
The majority of studies also agreed that unloader braces were a valuable treatment
for unicompartmental knee osteoarthritis, whether that be in reducing pain or looking
more specifically at the knee adduction moments during walking. Unfortunately, many
have short follow-up periods, small sample sizes, and most focus on medial compartment
osteoarthritis. This means we cannot draw similar conclusions from these studies like
we can in Lee et al's,[1] such as the fact that unloaders are able to delay surgery over the long term. Only
three papers were RCTs,[16]
[21]
[26] which carry the highest level of evidence. All three showed patients benefitted
from unloader brace treatment compared with conservative management.
Our results concurred with other literature studies, so are not novel findings but
reinforce the same conclusions. Ramsey and Russel,[29] in 2009, concluded that unloader knee braces are good at helping pain relief in
unicompartmental knee osteoarthritis. With regards to practice, it should be used
in conjunction with other conservative treatment and be considered before any type
of surgical intervention, a point emphasized by Lee et al[1] and Niazi et al.[25] A meta-analysis conducted by Moyer et al[30] in 2015 looked at the evidence presented in eight RCTs on valgus knee bracing for
medial compartmental osteoarthritis. They concluded that they were able to make a
strong recommendation about improvements with pain in patients with valgus knee braces
and a weak recommendation for improvement in function.[30] Petersen et al[31] focused on knee adduction moments and 20 out of the 24 articles they looked at concluded
that unloader braces reduced the knee adduction moment. The evidence from this review
and others combined should be enough to encourage further the use of knee unloader
braces in clinical practice.
Wilson et al[23] determined that patients preferred to opt for surgery over knee braces in the long
term, although this is in disagreement with Lee et al,[1] which found long-term use of the brace could delay or potentially nullify the need
for surgery. One of the reasons for lower rates of use, especially long term, could
be due to the complications of using knee braces. Lee et al[1] reported that 43% of patients in their study had soft tissue injuries which could
be due to poor fitting. Moyer et al,[30] in their meta-analysis, found compliance rates varied from 45 to 100%. Minor complications
mentioned in this review include that the brace was bulky; its fitting was constraining
or it slipped; and it caused swelling, blistering, and skin irritation.[30] Iqbal[26] reported 5 out of the 60 patients wearing bracing reported leg swelling. With regards
to major complications, there have been very few reported, although there have been
cases of thrombophlebitis and venous thromboembolism.[32]
[33]
To improve compliance, Lee et al[1] suggested regular follow-up appointments, in a nurse-led clinic, at 1, 3, and 6
months to address any issues. This way, complications can be monitored and the health
care service can check the patient is fitting the brace correctly, which was suggested
as the cause for many soft tissue issues. If there were any problems with fitting,
these could be corrected to avoid worsening of the problem and increasing the chances
of successful treatment.[1]
There were several studies present which also looked at lateral wedge foot insoles
as a potential treatment for unicompartmental knee osteoarthritis too. While two studies
suggested that they could be as good as knee braces,[21]
[28] Iqbal's[26] RCT showed that knee braces outperformed foot insoles in improvements in pain and
walking distance, so they may not be as suitable, despite the fact they had slightly
less complications. More patients in Iqbal's[26] study wanted to change from foot insoles due to lack of effect, than wanted to change
to knee braces.
Briggs et al[22] identified that two outcomes that patients expected as a result of treatment were
return to recreational sports and pain reduction. From the evidence above, it shows
that knee bracing may be able to manage these expectations (fully or partially), but
it is surprising that there have been reports that unloader knee braces are not regularly
prescribed in clinical practice. A study by Li et al[34] found that less than 12% of patients, suffering from unicompartmental osteoarthritis,
had tried knee bracing as part of their treatment. Although this study was in 2004,
it is backed up by two more recent studies showing big inconsistencies between clinical
practice and guidelines for knee osteoarthritis management.[32]
[35]
Future research needs to look into the disparity in volume of evidence between medial
and lateral unicompartmental knee osteoarthritis. Most of the studies in this review
were also short term (around 6 months) and more evidence is required to validate unloader
braces over a longer period of time. Two studies did look at the braces over 8 years[1] and 11 years,[23] but if unloader braces can actually delay the need for surgery then they need to
be effective over at least a 5-year period and the evidence needs to reflect this.
Also, there were very few studies looking at knee brace use for end-stage knee osteoarthritis,
so more research may be needed here to see how exactly they could be used for this
stage of the condition. More research will be needed to identify the optimal patient
who would benefit from unloader knee braces (with regards to gender, age, BMI, compartment,
etc.), although there are suggestions that every patient could benefit. A limitation
from this study include that we looked at a mix of studies with different outcomes,
so they were slightly harder to compare.
Conclusion
Current research has demonstrated the effectiveness of unloader braces in the management
of unicompartmental knee osteoarthritis over the short term; only two papers studied
the braces over a long period (8 and 11 years). Unloader braces are a cost-effective
management option to potentially delay the need for surgery for young patients or
those on long waiting lists. It has been shown to dramatically affect a patient's
quality of life and should be combined with other standard treatments as stated in
the guidelines for knee osteoarthritis management. More investigations are needed
into why prescription rates are low. Although we have explored some complications
and issues with compliance, these issues do not justify not considering an unloader
brace in every patient presenting with unicompartmental knee osteoarthritis. One reason
for this may be lack of awareness, and therefore more education on unloader braces
may be required. A nurse-led clinic for follow-up has been demonstrated to be an effective
approach to monitor compliance and complications. These conclusions are not novel
but support existing literature and this review can be added to the ever-growing pool
of evidence on the use of unloader braces. This evidence combined with previous studies
and reviews should lead to an increased uptake, acceptance, and usage of the braces.
Patients with unicompartmental knee osteoarthritis should be managed with a multidisciplinary
approach, an unloader knee brace, standard conservative management plus a follow-up
clinic lead by nurses; with the overall aim being to aid patients' quality of life
and to reduce the rates of knee replacements.