Knee Braces

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Knee Braces: Current Evidence and ClinicalRecommendations for Their Use

SCOTT A. PALUSKA, M.D.,and DOUGLAS B. MCKEAG, M.D., M.S., University of Pittsburgh Medical

CenterShadyside, Pittsburgh, Pennsylvania

Am Fam Physician. 2000 Jan 15;61(2):411-418.

See related patient information handout on knee braces, written by the authors of this article.

Methods of preventing and treating knee injuries have changed with the rapid development and

refinement of knee braces. Prophylactic knee braces are designed to protect uninjured knees from

valgus stresses that could damage the medial collateral ligaments. However, no conclusive

evidence supports their effectiveness, and they are not recommended for regular use. Functional

knee braces are intended to stabilize knees during rotational and anteroposterior forces. They

offer a useful adjunct to the treatment and rehabilitation of ligamentous knee injuries.

Patellofemoral knee braces have been used to treat anterior knee disorders and offer moderate

subjective improvement without significant disadvantages. Additional well-designed studies are

needed to demonstrate objectively the benefits of all knee braces. Knee braces should be used in

conjunction with a rehabilitation program that incorporates strength training, flexibility, activity

modification and technique refinement.

Musculoskeletal injuries are commonplace in family practice patients, and many knee joint disorders

are common among them. The knee is the largest joint in the body, and its exposed position makes it

vulnerable to injury during athletic activities.1,2 While strength, flexibility and technique have

historically been important components of knee injury management, the use of knee braces as

preventive and therapeutic adjuncts has gained recent attention.3,4 The occurrence of knee injuries

among high-profile athletes and the aggressive marketing of braces by manufacturers have also

contributed to interest in the use of knee braces. As a result, patients may consult their family

physicians for accurate, unbiased information about knee braces.

According to the American Academy of Orthopaedic Surgeons, 5 knee braces fit into several

categories: (1) prophylacticbraces intended to prevent or reduce the severity of knee injuries in

contact sports; (2) functionalbraces designed to provide stability for unstable knees; and (3)

rehabilitativebraces designed to allow protected and controlled motion during the rehabilitation of

injured knees. A fourth category includes patellofemoral braces, which are designed to improve

patellar tracking and relieve anterior knee pain.

Knee braces may minimize knee injuries, but their true effectiveness remains debatable. 1,2,69 The

current situation is one of confusion among players, coaches, parents and physicians about when

knee braces should be used, if at all. This article critically examines prophylactic, functional and

patellofemoral knee braces and attempts to assist primary care physicians in selecting the appropriatebrace for their active patients.

Prophylactic Knee Braces

After prophylactic knee braces were successfully tested in the National Football League, many

athletes wanted access to similar products for use during contact activities. The prophylactic knee

brace had been intended to protect the medial collateral ligament (MCL) during a valgus knee stress


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and to support the cruciate ligaments during a rotational stress.3 Their initial popularity has waned as

increasing evidence has questioned their effectiveness, particularly considering the high cost of

universal application.

BENEFITS AND LIMITATIONS

Shortly after the introduction of prophylactic braces, several national studies attempted to determinewhether they reliably prevent knee injuries. In general, inadequate control groups, subjective biases,

variable rules of football, alternative treatment modalities for MCL injuries and inconsistent methods

of data collection have limited comparison among most studies of prophylactic knee braces. 1012 Some

researchers have concluded that prophylactic knee braces significantly reduce MCL injuries,1113 while

others have noted few beneficial effects with regular use.10

As with many types of athletic braces, reported subjective benefits often exceed objective findings.

Brace wearers also have noted significant differences in joint position sense between braced and

unbraced legs, but this noted difference has not been consistently confirmed. 10

At best, prophylactic knee braces offer limited resistance to lateral knee impact and provide littlemeaningful rotational stress protection. At worst, they may generate increased forces that augment

associated injuries to the medial knee.3,10 The benefits and limitations of prophylactic knee braces are

summarized in Table 1.

TABLE 1.

Knee Brace Classification and Summary

Brace type IndicationsContraindications

Reportedbenefits/evidence

Risks/limitations

Prophylactic

knee braces

MCL protection against

valgus knee stressesRe-injury protection after

previous MCL

injuryAthletes at high

risk for MCL injury

To limit rotational

control in ACL-deficient

kneesUnstable

knees requiring

operative therapy

Reduction of frequency

and severity of MCLinjuries following valgus

knee stressesSupporting

cruciate ligaments during

rotational

stressesEnhanced knee

proprioception

Injuries

increased byexcessive

preloading of

MCL

Limited speed

and athleticism

False sense of

security for

previously

injured knee

Brace-related

contact injuries

to other playersFunctional

knee braces

Reduce translation and

rotation following ACL

injuryAdditional support

after ACL

surgerySupport for mild

to moderate PCL or

MCL instability

Unstable knees

requiring operative

therapyComplicate

d multi-directional

knee injuries such

as posterolateral

corner injuries

Laboratory evidence of

reduced tibial rotation

and knee AP

translationSubjective

reports of decreased

pain, enhanced

performance, and

improved confidence

Reported effects

on translation

and rotation

disappear at

physiologic

levels of use

Increased

energy


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Brace type IndicationsContraindications

Reportedbenefits/evidence

Risks/limitations

during athleticsControl of

knee

hyperextensionAugment

ed knee proprioception

expenditure and

decreased agility

False sense of

confidence

following ACLreconstruction

Brace-related

contact injuries

to other players

Patellofemor

al knee

braces

Patellar subluxation

and/or

dislocationPatellar

tendonitisChondromalac

ia of the

patellaPostsurgical

effusion control

Knee disorders

unrelated to the

patellofemoral

jointKnee

translation or

rotational

controlUnstable

knees requiringoperative therapy

Improved patellar

tracking during knee

flexion and

extensionDissipated

lateral patellar

forcesDecreased anterior

knee pain

syndromesSubjectivereports of decreased

pain, enhanced

performance and

improved confidence

during athletics

Subjective

benefits exceed

objective

findings

Increased skin

irritation and

lesions

Relativelyinsignificant pain

relief with

regular brace

wear

Less effective

than

conservative

therapy (simple

stretching and

strengthening)

MCL = medial collateral ligament; ACL = anterior cruciate ligament; PCL = posterior cruciate ligament; AP =anteroposterior.

Despite a lack of conclusive research, many players and coaches still consider using prophylactic

knee braces. Skill players in football (receivers, kickers and running backs) have voiced the

concern that prophylactic knee braces limit speed and agility, so they typically avoid routine brace

wear. On the other hand, offensive and defensive linemen who are at greatest risk for injury wear

prophylactic knee braces more frequently.11,12 Many players wear prophylactic knee braces in practices

but not in games, because of feared performance limitations.

OBTAINING AND FITTING A PROPHYLACTIC KNEE BRACE

Currently, most prophylactic knee braces use unilateral or bilateral bars with hinges. Examples ofboth types are shown in Figure 1.

FIGURE 1.


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Prophylactic knee braces: (A) with a unilateral-hinged bar, viewed from the side; (B) with a unilateral-hinged bar,

viewed from the front; (C) with bilateral-hinged bars.

Parts A andCofFigure 1 reprinted with permission from dj Orthopedics.

In choosing a prophylactic knee brace, physicians should select the longest brace that fits the athlete's

leg, as shorter braces provide less MCL protection.3 Trying on several different braces before

purchase may be helpful for determining the best fit. Cost is greater for custom braces than for off-

the-shelf models; however, custom models provide few additional benefits. In addition, physicians

may wish to contact several distributors or suppliers, as prices vary considerably. Details of various

braces are given in Table 2. Brace efficacy depends on proper application. Regular tightening of

straps, tape or hook-and-pile fasteners helps reduce unwanted brace migration. Also, shaving leg hair

and fitting a brace closely to the contours of the leg may improve brace-skin contact and limit

unwanted slippage. Correctly placing the hinge(s) relative to the femoral condyles is essential for

optimal brace performance with minimal range of motion diminishment. Finally, prophylactic knee

braces should be assessed daily by trainers and players for positioning and structural integrity. A

broken or damaged prophylactic knee brace should be replaced to ensure maximum functionality.

TABLE 2.

Knee BracesManufacturers and Product Information

Manufacturer/telephonenumber

Knee bracetype Name of product

Additionalinformation Cost*

dj Orthopedics800-336-6569 Prophylactic DonJoy Protective

Knee Guard

Unilateral support $ 44

Prophylactic DonJoy Playmaker Bilateral support 125

Functional DonJoy Legend Presized fit 325

Functional DonJoy Defiance Custom fit 525

Patellofemoral DonJoy On-Track 79

Omni Scientific800-875-9080 Prophylactic Anderson KneeStabilizer 1

Unilateral support 110

Prophylactic Anderson Knee

Stabilizer 2

Bilateral support 120

Functional Omni Scientific

Spectrum

Presized fit 375

Functional Omni Scientific Avant

Guard

Custom fit 550

Patellofemoral Omni Scientific Sport

Sleeve

40

McDavid Knee Guard, Inc.800-

237-8254

Prophylactic McDavid Protective

Knee Guard

Unilateral support 45 to 60

Prophylactic McDavid Pro Stabilizer Bilateral support 48 to 60Bledsoe Brace Systems800-527-

3666

Functional Bledsoe Ultimate CI Presized fit 325

Patellofemoral Bledsoe Sport Max 55 to 89

DePuy Ortho Tech800-227-1554 Functional Ortho Tech Ultimate

Controller

Presized fit 280

Functional Ortho Tech Montana Custom fit 700

Patellofemoral Ortho Tech Neopatellar

Stabilizer

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Some researchers found that energy expenditure increased with functional knee brace use during

lengthy athletic endeavors, but others reported no adverse performance effects.3,14,16,17 The regional

muscle ischemia and lactic acid build-up observed with brace use may precipitate an increase in

muscle fatigue.4,17 Researchers have also concluded that functional braces provide few proprioceptive

effects and may expose athletes to additional risk by imparting a false sense of confidence.4,8,14,17

Strengths and weaknesses of functional knee braces are outlined in Table 1.

OBTAINING AND FITTING A FUNCTIONAL KNEE BRACE

Functional knee braces are available in custom or presized models. Both categories use a hinge-

post-shell or a hinge-post-strap design, which differ in their thigh and calf enclosures. The former

uses a molded shell of plastic and foam, while the latter uses a system of straps around the thigh and

calf.3 Some studies have suggested that hinge-post-shell designs provide improved tibial-

displacement control, greater rigidity, enhanced durability and better soft tissue contact.2,14,16 Examples

of functional knee braces are shown in Figure 2.

FIGURE 2.

Hinge-post-shell functional knee braces are designed to reduce knee instability following injury.

Reprinted with permission from dj Orthopedics (part A), Innovation Sports (partB) andBledsoe Brace Systems (partC).

Custom braces require several measurements of the affected leg to be taken to produce a brace that

closely conforms to the desired size. Presized braces are sized by measuring the thigh circumference

6 in above the mid-patella and selecting the corresponding brace size. Presized braces may be

desirable for use in patients who have changing limb girths during rehabilitation. In contrast, custom

functional knee braces are more appropriate for abnormal limb contours and high-level athletes, or

for enhanced patient comfort.2

Because studies comparing prefabricated and custom braces have found few significant clinical

differences, presized braces may be better when cost or rapid availability is important.8,17

Costs varyconsiderably, so several suppliers should be contacted before a brace is purchased. Details of various

functional knee braces are given in Table 2.

Accurate sizing will limit brace migration and improve brace effectiveness. Most companies make

braces of different lengths, and the longest length the athlete can comfortably wear should be chosen.

Setting 10 to 20 degrees of extension limitation may help minimize hyperextension of the knee

joint.2 Attention to correct hinge placement relative to the femoral condyles improves the overall


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brace performance and efficacy.8 Finally, any exposed metal should be covered to limit brace-

induced injuries to others, and more durable materials should be chosen for contact sports.

FUNCTIONAL BRACE SUMMARY

Functional knee braces deserve consideration as a component of the treatment and rehabilitation for

ligamentous knee instability. They offer some control of external knee rotation and anteroposteriorjoint translation. 17 Functional knee braces are also useful adjuncts to muscular rehabilitation for graft

protection following ACL reconstruction.7 Although brace wearers consistently report subjectively

improved knee stability and function, the objective effects of functional knee braces appear to

diminish at physiologic stress levels.4,8

While functional knee braces have not been shown to be harmful, their correct application depends

on appropriate rehabilitation and activity modification. Overall, lower extremity muscle

strengthening, flexibility improvements and technique refinement are more important than functional

bracing in treating ligamentous knee injuries.

Patellofemoral Braces

Anterior knee pain is a common disorder among active persons of all ages. Although definitions

vary, the painful anterior knee syndrome is most often thought to originate from a malalignment of

the patellofemoral joint.9,18-20 Patellofemoral braces were introduced to resist lateral displacement of

the patella, maintain patellar alignment and, theoretically, decrease knee pain.3,15 Low cost, ease of use

and availability promoted their widespread use. Nevertheless, many efficacy claims made by brace

companies are not based on objective evidence.6,21

BENEFITS AND LIMITATIONS

General agreement exists regarding the utility of conservative therapy in the initial management of

anterior knee pain.9,22 Less clear is the role of bracing as part of the therapeutic regimen. Several

studies have demonstrated significant improvements in patellofemoral pain symptoms with the use of

patellofemoral knee braces,18,19,21,23 but others have found them to be ineffective.6,24

This lack of consensus stems from the absence of well-controlled studies addressing their efficacy.

Nonetheless, patients appear to welcome patellofemoral braces and report significant subjective

improvements in pain and disability with brace wear.18,21,23,25 A compilation of reported benefits and

limitations of patellofemoral braces is outlined in Table 1.

OBTAINING AND FITTING A PATELLOFEMORAL BRACE

Many different patellofemoral knee braces are currently available, and some examples are shown

inFigure 3. They usually incorporate an elastic material such as neoprene and may include straps or

buttresses that help to stabilize the patella. For most persons, an off-the-shelf version can be

successfully fitted and used without the need for customization. 3 A more active person may prefer a

patellofemoral brace with a lateral hinge and adjustable patellar buttress. Details of various braces are

given in Table 2.


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FIGURE 3.

Patellofemoral knee braces are intended to resist lateral displacement of the patella and thereby decrease knee pain.

Reprinted with permission from dj Orthopedics.

Brace effectiveness depends on correct application and use, and steps for accurately fitting

patellofemoral braces are listed in Table 3. Counterbalancing straps are usually secured superiorly

but may be placed inferiorally for infrapatellar tendonitis. Buttresses are typically placed laterally,

but medial placement may diminish medial patellar subluxation. Shoe orthotics should be considered

in addition to a brace for patients with recalcitrant patellofemoral pain syndrome. 22

TABLE 3.

Fitting a Patellofemoral Knee Brace

Obtain circumference of affected leg(s) according to the selected manufacturer's specific guidelines by

measuring:3 in above and 3 in below mid-patella

or

Around center of knee joint with leg relaxed and extended.

Select the corresponding brace size (XS to XXL).

Pull brace onto affected leg(s). Most can be worn interchangeably on either knee.

After determining desired medial or lateral placement, position buttress support(s) comfortably if

adjustable.

Align patella in center of cutout if applicable.

Secure counterbalancing strap(s) if present with moderate tension. Remove excess strap material as

needed.

Periodically inspect brace for migration, strap loosening or material fatigue.

PATELLOFEMORAL BRACE SUMMARY

Patellofemoral braces are an inexpensive, subjectively helpful component of anterior knee pain

therapy. Their mechanism of action remains unclear, but most appear to improve patellar tracking

through a medially directed force.25 Changes in regional temperature, neurosensory feedback or

circulation may also contribute to their effects.23 Overall, patellofemoral braces should be used in

conjunction with a comprehensive knee rehabilitation program that includes strengthening, flexibility

and technique improvements.

The Authors

SCOTT A. PALUSKA, M.D., is currently in private practice in Cary, N.C. Dr. Paluska graduated from the University ofMichigan School of Medicine in Ann Arbor, where he also completed a residency in family medicine. He completed afellowship in primary care sports medicine at the University of Pittsburgh (Pa.) Medical Center. He assists in medicalcare for the Carolina Hurricanes.

DOUGLAS B. MCKEAG, M.D., M.S., is currently professor and chair of the department of family medicine at IndianaUniversity School of Medicine and director of sports medicine at the National Institute for Fitness and Sports, both inIndianapolis. Dr. McKeag was previously the Arthur J. Rooney chair of sports medicine at the University of Pittsburgh(Pa.) School of Medicine. He serves on the editorial board of the American Academy of Family Physicians and isfounder and past president of the American Medical Society for Sports Medicine.


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Address correspondence to Scott A. Paluska, M.D., Rex Family Practice ofCary, 1515 S.W. Cary Parkway, Suite200, Cary, NC27511. Reprints are not available from the authors.

The authors thank NancyMcElwain, Ph.D., for support in the preparation of the manuscript.

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