Effects of protective knee bracing on speed and agility

Functional knee brace use for 21 h leads to a longer duration to achieve peak vertical ground reaction forces and the removal of the brace after 17.5 h results in faster loading of the knee joint

PURPOSE

To investigate the landing strategies used after discontinuing and continuing the use of a functional knee brace (FKB) while performing a drop jump.

METHODS

Following published methodology and power analysis, 23 uninjured male athletes, mean age of 19.4 ± 3.0 years, performed seven tests, during three test conditions (nonbraced, braced and removed brace or continued brace use), over 6 days of 12 testing sessions (S) for a total of 38.5 h. Each subject was provided with a custom-fitted FKB. This study focuses on the single leg drop jump kinetics during S12 when subjects were randomly selected to remove the FKB after 17.5 h or continued use of FKB. The time to peak vertical ground reaction forces (PVGRF) and PVGRF were recorded on landing in eight trials.

RESULTS

After brace removal, a significantly shorter mean time to PVGRF was recorded (9.4 ± 22.9 msec (3.9%), p = 0.005, 95% confidence interval (95% CI): -168.1, 36.1), while continued brace use required a nonsignificant (n.s.) longer mean duration to achieve PVGRF (19.4 ± 53.6 msec (8.9%), n.s., 95% CI: -49.7, 73.4). No significant mean PVGRF difference was found in brace removal (25.3 ± 65.8 N) and continued brace use (25.1 ± 23.0 N).

CONCLUSION

Removal of FKB after 17.5 h of use led to a significantly shorter time to achieve PVGRF, while continued brace use for 21 h required a longer duration to achieve PVGRF, suggesting faster and slower knee joint loading, respectively. Understanding the concerns associated with the use of FKB and the kinetics of the knee joint will assist clinicians in counselling athletes about the risks and benefits of using an FKB.

LEVEL OF EVIDENCE

Level II.

Prophylactic Knee Bracing in Offensive Linemen of the National Football League: A Retrospective Analysis of Usage Trends, Player Performance, and Major Knee Injury

Background

Offensive linemen in American football are prone to high-energy valgus forces to the knee, leading to associated injuries. Some offensive linemen in the National Football League (NFL) wear prophylactic knee braces (PKB) to prevent ligamentous injury.

Purpose/Hypothesis

This purpose of the study was to compare injury rates and performance between NFL offensive linemen who wear PKB and those who do not. It was hypothesized that brace wear would be associated with fewer major knee injuries and no difference in gameplay performance.

Study Design

Cohort study; Level of evidence, 3.

Methods

For the 2014 through 2020 NFL seasons, offensive linemen with at least 200 game snaps per regular season were identified. Players were grouped by PKB status (bracers vs nonbracers) based on visualization of bilateral, dual-hinged metal knee braces as part of gameday uniforms on publicly available imaging databases and/or game videos. Major knee injuries, defined as those requiring the missing of games, were identified using publicly available data. Performance was assessed with Pro Football Focus grades for each season. Rates of major knee injury were compared between groups with the 2-sample Z test for proportions, and performance grades were compared with the unpaired t test.

Results

For the cumulative study period, bracers demonstrated a significantly lower rate of major knee injuries than nonbracers (0.013 vs 0.049 injuries per player, respectively; P = .04). Isolated MCL injury was the most common injury for nonbracers. There was no group difference in performance for the cumulative study period or during most individual seasons. Yearly prevalence of PKB usage declined steadily from 16.3% in 2014 to 5.6% in 2020. A subgroup analysis of rookie players demonstrated an overall downtrend in usage during the study period as well.

Conclusion

Results indicated that knee brace prophylaxis by NFL offensive linemen was associated with a reduced risk of major knee injury without a significant difference in performance when compared with nonbracers. Despite this, the prevalence of PKB declined over the study period.

Biomechanical Effects of Prophylactic Knee Bracing on Anterior Cruciate Ligament Injury Risk: A Systematic Review

OBJECTIVE

Prophylactic knee braces (PKBs) are widely used by athletes in pivoting and landing sports and have the potential to influence knee movement and alignment, thus modulating anterior cruciate ligament (ACL) injury risk. This systematic review analyses current evidence on the biomechanical effects that PKBs have in the prevention of ACL injuries.

DATA SOURCES

The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Searches were conducted on PubMed, Web of Science, Scopus, Ovid MEDLINE, EMBASE, Cochrane, and CINAHL for studies published from inception until May 31, 2021. Included studies assessed the effects of PKBs on biomechanical variables associated with ACL injuries in landing or pivoting tasks, comparing between braced and unbraced conditions.

MAIN RESULTS

A total of 234 articles were identified; from which, 14 controlled, laboratory, biomechanical studies were included in this review. The effects of PKBs on knee biomechanics could be divided into kinematic variables in the coronal, sagittal, and transverse planes; and common kinetic variables, such as ground reaction force (GRF) and ACL load/strain. Also, PKBs were found to have protective effects in coronal and transverse plane kinematics, but results in the sagittal plane were inconclusive. Assessing knee kinetics, PKBs were advantageous in decreasing ACL load/strain but had no significant effect on GRF.

CONCLUSIONS

Prophylactic knee braces may serve to reduce ACL injury risk by modulating knee coronal and transverse plane movements and ACL load/strain during high-risk maneuvres. Precise recommendations are limited by study heterogeneity. More prospective studies are needed to assess ACL injury risk during high-risk sports using specific PKBs.

Efficacy of Prophylactic Knee Bracing in Sports

Anterior cruciate ligament (ACL) and medial collateral ligament (MCL) injuries are common knee injuries, which can result from contact and noncontact during sports, recreation, or work-related activities. Prophylactic knee braces (PKBs) have been designed to protect the knee and decrease risk of recurrence of these injuries. Despite their success, PKBs have not been proven to be consistently effective and cost of the device must be evaluated to optimize its use in sports, particularly American football. Biomechanical studies have suggested that increased hip and knee flexion angles may reduce frontal plane loading with bracing which can protect the knee joint. This is essential with knee loading and rotational moments because they are associated with jumping, landing, and pivoting movements. The clinical efficacy of wearing PKBs can have an impact on athletic performance with respect to speed, power, motion, and agility, and these limitations are evident in athletes who are unaccustomed to wearing a PKB. Despite these concerns, use of PKBs increases in patients who have sustained an MCL injury or recovering from an ACL reconstruction surgery. As the evidence continues to evolve in sports medicine, there is limited definitive data to determine their beneficial or detrimental effects on overall injury risk of athletes, therefore leading those recommendations and decisions for their usage in the hands of the athletic trainers and team physicians' experience to determine the specific brace design, brand, fit, and situations for use.

Knee Pads Do Not Affect Physical Performance in Young Female Volleyball Players

Knee pads have become increasingly popular among volleyball players. Given the fact high-intensity activities that are crucial to successfully playing this sport lead to an increased risk of a knee injury, the primary use of knee pads is to prevent potential injury. However, no research has been carried out to explain the effects of knee pads on the most important physical abilities in volleyball players, thus directly affecting performance. This study was undertaken to determine the effects of knee pads on the explosive power of the lower extremities, linear speed, and agility in young female volleyball players. In two separated sessions, 84 female volleyball players (age: 14.83 ± 0.72 years; height: 163.19 ± 8.38 cm; body mass: 53.64 ± 10.42 kg; VE: 5.30 ± 3.39 years) completed squat jumps (SJ), countermovement jumps (CMJ) with and without arm swing, linear sprints at 5-m and 10-m, modified t-test, and 5-10-5 shuttle test. Data analyses included descriptive statistics, paired sample T-tests and use of effect size (ES). There was no statistical difference between the two conditions for SJ (p = 0.156; ES = 0.18), CMJ (p = 0.817; ES = 0.03), CMJ with arm swing (p = 0.194; ES = 0.14), linear sprint at 5 m (p = 0.789; ES = 0.03) and 10 m (p = 0.907; ES = −0.01), modified t-test (p = 0.284; ES = 0.13), and 5-10-5 shuttle test (p = 0.144; ES = 0.19). Wearing knee pads has neither an inhibitory nor positive effects on explosive power of the lower extremities, linear speed, and agility in young female volleyball players.

Do neoprene sleeves and prophylactic knee braces affect neuromuscular control and cutting agility?

OBJECTIVES

To evaluate the effects of neoprene sleeves (NSs) and prophylactic knee braces (PKBs) on neuromuscular control and cutting agility.

DESIGN

Markerless motion-capture technology tracked subjects (1) without a brace as a control (2) with NSs and (3) with PKBs during single-leg drop vertical jump (SLDVJ), single-leg squat (SLS), Y-excursion, and cutting movements. Movements were recorded five times per bracing condition in three different sessions.

SETTING

University laboratory.

PARTICIPANTS

Ten healthy, active subjects (5 male, 5 female; age range, 22-26 years).

MAIN OUTCOME MEASURES

Degrees of motion and time to completion.

RESULTS

Use of NSs and PKBs reduced subjects' hip internal rotation in the loading phase of SLDVJ (p = 0.026, 0.02) and SLS (p = 0.005, <0.001), reduced knee flexion in the loading phase of SLDVJ (p = 0.038, <0.001), and reduced knee frontal plane abduction (FPA) with SLS (p = 0.015, 0.024) and Y-excursion (p = 0.002, 0.005) compared to control. Use of PKBs decreased subjects' hip internal rotation in the Y-excursion (p = 0.024) and reduced knee FPA in the SLDVJ loading phase (p = 0.014) compared to control. There was no difference in cutting agility for either group (p = 0.145, 0.347).

CONCLUSION

Both NSs and PKBs positively impacted neuromuscular control without impacting cutting agility.

The effect of knee brace and knee sleeve on the proprioception of the knee in young non-professional healthy sportsmen

BACKGROUND

Proprioception has been defined as the capacity to feel the position of a joint in space as sensed by the central nervous system. Prophylactic knee braces are supposed to help in knee injury prevention not just with a mechanical support of the joint but also improving proprioception. The main aim of this study was to determine the effects of a knee brace and a knee sleeve on knee proprioception. The secondary aim was to determine if different starting angles of the knee and different movement directions influence knee proprioception.

METHODS

We tested a group of twenty healthy male sport students without knee injuries. They were tested with the brace, with the sleeve and without support. The threshold of detection of passive knee movement with a starting knee angle of 30° and 60°, both in flexion and extension was determined.

RESULTS

We did not find any statistically significant change in the threshold of detection of passive knee movement wearing the brace or the sleeve compared to the unsupported condition (p=0.462, α=0.05). We found a significantly lower proprioceptive sensitivity starting at the more flexed knee angle (p=0.005, α=0.05) and moving in extension than in the other test situations (p=0.001, α=0.05).

CONCLUSION

Movement direction and starting position appear to influence the threshold of detection of passive knee movement. The results of this study also suggest that knee supports do not influence either positively or negatively knee proprioception of uninjured active subjects.

Anterior cruciate ligament bracing: evidence in providing stability and preventing injury or graft re-rupture

Ligamentous knee injuries are common and costly, both in financial terms and time missed from work and recreational activities. Furthermore, ligamentous injuries appear to predispose patients to future osteoarthritis and other morbidities. Therefore, prevention strategies are important in limiting the potential impact of these injuries. Knee braces are one of the most often prescribed devices in the billion-dollar orthotic industry. Despite widespread use of prophylactic and functional knee braces, the evidence supporting their efficacy in reducing and/or preventing injury remains limited. Knee braces have been shown to be more effective in preventing medial collateral ligament injuries than anterior cruciate ligament injuries in both cadaveric and clinical studies. The use of functional braces after anterior cruciate ligament reconstruction has been supported and refuted in both postoperative and long-term studies.

Current recommendations for anterior cruciate ligament bracing: when to use

Braces are often used during various stages of recovery from an anterior cruciate ligament tear despite there being sparse definitive research supporting their use. This article reviews the literature on brace use for patients with anterior cruciate ligament tears in order to provide a guide for clinicians. There is evidence to support immediate postoperative bracing, with the goals of maintaining full extension and decreasing effusion. There may be a psychological benefit for its use in return to sport; however, this should be weighed against decreased performance. In the context of modern graft-fixation techniques and early mobilization protocols, empiric functional brace prescription is not required for successful long-term clinical outcomes and return to sport.

The effects of a prophylactic knee brace and two neoprene knee sleeves on the performance of healthy athletes: a crossover randomized controlled trial

Knee injury is one of the major problems in sports medicine, and the use of prophylactic knee braces is an attempt to reduce the occurrence and/or severity of injuries to the knee joint ligament(s) without inhibiting knee mobility. The aim of the present study was to examine the effect of one recently designed prophylactic knee brace and two neoprene knee sleeves upon performance of healthy athletes. Thirty-one healthy male athletes (age = 21.2 ± 1.5) volunteered as participants to examine the effect of prophylactic knee brace/sleeves on performance using isokinetic and functional tests. All subjects were tested in four conditions in a random order: 1. nonbraced (control) 2. using a neoprene knee sleeve 3. using a knee sleeve with four bilateral metal supports and 4. using a prophylactic knee brace. The study design was a crossover, randomized, controlled trial. Subjects completed single leg vertical jump, cross-over hop, and the isokinetic knee flexion and extension (at 60, 180, 300°/sec). Data were collected from the above tests and analyzed for jump height, cross-over hop distance, peak torque to body weight ratio and average power, respectively. Comparisons of these variables in the four testing conditions revealed no statistically significant difference (p>0.05). The selected prophylactic brace/sleeves did not significantly inhibit athletic performance which might verify that their structure and design have caused no complication in the normal function of the knee joint. Moreover, it could be speculated that, if the brace or the sleeves had any limiting effect, our young healthy athletic subjects were well able to generate a mean peak torque large enough to overcome this possible restriction. Further studies are suggested to investigate the long term effect of these prophylactic knee brace and sleeves as well as their possible effect on the adjacent joints to the knee.

The effect of prophylactic knee bracing on performance: balance, proprioception, coordination, and muscular power

PURPOSE

Prophylactic knee braces are largely used in the prevention of ligament injuries, but their effectiveness on performance are still controversial. The aim of this study was to determine which brace was the most effective on functional performance.

METHOD

Twenty-four healthy subjects (14 men and 10 women), between the age of 18 and 22 with no prior history of lower limb injury and brace use, voluntarily participated in this study. Five different prophylactic knee braces were used. The test protocol consisted of dynamic balance, jumping performance, proprioception, coordination, and maximal force. Balance was assessed by the Y balance test; jumping performance was assessed by vertical jump and one-leg hop tests; maximal force, proprioception, and coordination were assessed by using functional squat testing. Proprioceptive test was performed by using the functional squat system machine that the participants were instructed to keep the crosshair on the line, even after the visual aid had disappeared. The subjects without a brace and with the brace by using 5 different braces (DonJoy-USA) were evaluated by five different therapists.

RESULTS

Hinged "H" buttress for the support of the knee brace was found to be more effective than the others in terms of balance. Drytex economy hinged knee brace had the best result in terms of proprioception and maximal force. There were no significant differences in vertical jump and one-leg hop tests (n.s.).

CONCLUSION

In conclusion, the hinged "H" buttress for support of the knee brace and Drytex economy hinged knee brace produced the best results on the performance parameters. The other three braces demonstrated more variable and less optimal results. Prophylactic knee braces can be used for both healthy subjects and athletes to enhance proprioception, coordination, maximal force, and balance, but it is important to choose the best proper brace to the individuals according to their fitness level.

LEVEL OF EVIDENCE

(Economic and decision analysis-developing an economic or decision model), Level II.

Performance of healthy braced participants during aerobic and anaerobic capacity tasks

CONTEXT

Knee braces were introduced in sports approximately 30 years ago. However, the effects of a functional knee brace (FKB) on aerobic and anaerobic performance after fatigue are unknown.

OBJECTIVE

To investigate whether FKB use in noninjured participants hindered performance during aerobic (Léger beep test) and anaerobic (repeated high-intensity shuttle test [RHIST]) tasks.

DESIGN

Crossover study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty-seven healthy male provincial and national basketball and field hockey athletes (age = 19.4±3.0 years, range, 17-26 years; height = 182.6±6.8 cm, range, 168-196 cm; mass = 80.0±9.1 kg, range, 66-108 kg).

INTERVENTION(S)

Each participant was provided a custom-fitted FKB and performed 5 nonbraced (NBR) testing sessions over 3 days, followed by 5 braced (BR) testing sessions over 3 days, for a total of 17.5 hours of testing per condition. During each testing session, participants performed 1 trial of the Léger beep test and 1 trial of the RHIST in each condition.

MAIN OUTCOME MEASURE(S)

Predicted maximal oxygen consumption (Vo(2) max) and time performance measures were recorded for each NBR and BR trial.

RESULTS

Initial performance levels were lower for BR than NBR for both the Léger beep test (BR = 44.3 mL/kg/min, NBR = 47.3 mL/kg/min; F(1,26) = 8.726; P = .007) and the RHIST (BR = 16.5 seconds, NBR = 16.2 seconds; F(1,26) = 13.98, P = .001). However, with continued FKB use, the aerobic performance measure remained higher for only the first 2 BR testing sessions (NBR = 46.9 mL/kg/min, BR = 42.4 mL/kg/min; F(3.0,79.8) = 4.95, P = .003). For the anaerobic test, no performance difference was noted between the testing conditions (NBR = 16.2 seconds, BR = 16.4 seconds; P = .7), whereas fatigue levels were lower during BR testing sessions (NBR = 33%, BR = 31%). After 14.0 hours of FKB use, performance levels were almost equal between the testing conditions (NBR = 47.6 mL/kg/min, BR = 46.1 mL/kg/min).

CONCLUSIONS

We found an initial decrement in performance when the FKB was used during an aerobic or anaerobic task. However, after 14.0 hours of FKB use, accommodation to the FKB was possible.

Knee injuries and the use of prophylactic knee bracing in off-road motorcycling: results of a large-scale epidemiological study

BACKGROUND

The effectiveness of prophylactic knee bracing in preventing knee injuries during sports has been evaluated; however, because of the variability in study conclusions, the topic remains controversial. Despite a paucity of data, the authors believe that prophylactic knee bracing is frequently used in off-road motorcycling.

HYPOTHESIS

No statistically significant difference exists in the frequency and types of knee injuries incurred between braced and nonbraced riders using commercially available knee braces in off-road motorcycling.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Data from 2115 off-road motorcycle riders was obtained using an Internet-based survey over a 1-year period. Participants were grouped by use or nonuse of prophylactic knee bracing, and an incidence rate ratio was used for injury rate comparison.

RESULTS

Participants recorded 39 611 riding hours over the study period. A total of 57 riders (2.7%) sustained at least 1 knee injury, for a total of 89 injuries. The most common injuries involved the anterior cruciate ligament, menisci, and medial collateral ligament. There was a significantly higher rate of overall injuries in the nonbraced group versus the braced group (3.675 vs 1.587 per 1000 rider hours, P < .001). Significantly higher incidence rates of anterior cruciate ligament rupture (1.518 vs 0.701 per 1000 rider hours, P = .0274) and medial collateral ligament injury (0.799 vs 0.111 per 1000 rider hours, P = .002) were found among nonbraced riders compared with braced riders.

CONCLUSION

The most common knee injuries in off-road motorcycling involve the anterior cruciate ligament, menisci, and medial collateral ligament. The use of prophylactic knee bracing appears to have a beneficial effect in preventing medial collateral ligament and anterior cruciate ligament injuries as well as overall knee injury occurrence. These findings may be applicable to other sports that involve similar forces and mechanics.

Treatment of medial collateral ligament injuries

The medial collateral ligament is the most frequently injured ligament of the knee. The anatomy and biomechanical role of this ligament and the associated posteromedial structures of the knee continue to be explored. Prophylactic knee bracing has shown promise in preventing injury to the medial collateral ligament, although perhaps at the cost of functional performance. Most isolated injuries are treated nonsurgically. Recent studies have investigated ligament-healing variables, including modalities such as ultrasound and nonsteroidal anti-inflammatory drugs. Concomitant damage to the anterior or posterior cruciate ligaments is a common indication to surgically address the high-grade medial collateral ligament injury. The optimal treatment of multiligamentous knee injuries continues to evolve, and controversy exists surrounding the role of medial collateral ligament repair/reconstruction, with data supporting both conservative and surgical management.

The effect of functional knee brace design and hinge misalignment on lower limb joint mechanics

BACKGROUND

Knee bracing has been shown to alter lower limb joint mechanics, which may protect the anterior cruciate ligament. The effect of brace alignment and brace type, however, remains largely unknown. This study was conducted to determine whether the use of a functional knee brace, the type of brace used or its alignment relative to the knee causes biomechanical alterations to gait.

METHODS

Ten healthy participants took part in two walking conditions (aligned brace and misaligned brace) for two different types of brace (sleeve brace with bilateral hinges and hinge-post-shell). A non-braced condition was included as a baseline measure. Three-dimensional kinematics and force platform data were used to calculate the joint intersegmental forces and net joint moments of the ankle, knee and hip.

FINDINGS

In comparison to non-braced walking, the shell brace in its aligned position significantly reduced the peak ankle plantarflexor moment. There was a decreased peak knee flexion angle with both the aligned shell and sleeve braces. The shell brace in its aligned position significantly increased peak knee adduction and reduced peak knee internal rotation.

INTERPRETATION

In this sample of healthy participants, functional knee bracing failed to alter lower limb mechanics in such a way that would reduce the force transmitted to the anterior cruciate ligament. In addition, although there were brace induced changes in lower limb kinematics with 2cm of distal hinge misalignment, it is unlikely that hinge misalignment of this magnitude is detrimental to an uninjured knee joint during walking.

Current evidence and clinical applications of therapeutic knee braces

Braces are commonly used for the management of musculoskeletal injuries. With improvements in design and application, the knee brace has gained recognition by many as a treatment and prevention modality. However, there exist many different categories of knee braces, leading to confusion among many end users. The theoretical basis of the mechanism of action of the unloader, prophylactic, patellofemoral, and functional knee braces are explained in this review. This article also provides an update on the various knee braces in terms of the clinical efficacy and appropriate prescription recommendations.

Temporal Influences of Functional Knee Bracing on Torque Production of the Lower Extremity

Context:

Functional knee braces (FKB) are used prophylactically and in rehabilitation to aide in the functional stability of the knee.

Objective:

To determine if alterations in select lower extremity moments persist throughout a one hour period in healthy individuals.

Design:

2X5 repeated measures design.

Setting:

Biomechanics Laboratory.

Subjects:

Twenty subjects (14 male and 6 female, mean age 26.5±7 yrs; height 172.4±13 cm; weight 78.6±9 kg), separated into braced (B) and no brace (NB) groups.

Intervention:

A one-hour exercise program divided into three 20 minute increments.

Main Outcome Measures:

Synchronized three-dimensional kinematic and kinetic data were collected at 20-minute increments to assess the effect of the FKB on select lower extremity moments and vertical ground reaction forces.

Results:

Increase in hip moment and a decrease in knee moment were noted immediately after brace application and appeared to persist throughout a one hour bout of exercise.

Conclusions:

The FKB and the exercise intervention caused decreases in knee joint moments and increases in hip joint moments.

Conservative and Postoperative Rehabilitation of Isolated and Combined Injuries of the Medial Collateral Ligament

Injuries to the medial collateral ligament (MCL) are very common and there seems to be a consensus supporting the conservative management of grade I and II tears. Grade III tears are also usually treated conservatively unless associated with injuries to the anterior cruciate ligament or posterior cruciate ligament. This article outlines rehabilitation programs for conservative treatment of MCL injuries, and postoperative programs after anterior cruciate ligament or multiple ligament reconstruction. In addition, the use of functional and prophylactic bracing for injuries of the MCL is reviewed.

The use of knee braces, part 1: Prophylactic knee braces in contact sports

Surrogate knee model biomechanical studies have indicated that off-the-shelf braces provide 20% to 30% greater resistance to a lateral blow when the knee is in full extension. Custom functional braces doubled the protective effects and proved effective with the knee in some flexion. Although functional performance studies are not consistent, preventive knee braces may slow straight-ahead sprint speed, cause early fatigue, and increase muscular relaxation pressures, energy expenditure, blood lactate levels, maximal torque output, oxygen consumption, and heart rate. Two epidemiologic studies have been performed. At West Point, a randomized control study of 71 injuries in 1396 cadets indicated knee brace effectiveness with a statistically higher rate of injury in the control group (3.4/1000 exposures) than in the braced group (1.5/1000 exposures), with the most significance for medial collateral ligament sprains in defensive players. The Big Ten Conference conducted a descriptive study of 100 medial collateral ligament sprains among 987 players in different positions, strings, and types of session. Brace-wear tendency varied directly with the unbraced player counterpart's risk of medial collateral ligament sprain, with the nonplayer linemen experiencing both the greatest risk of unbraced practice session injury (0.0801 injuries/1000 exposures) and the highest incidence of brace wear (85%). During practices, there was a nonsignificant but very consistent reduction in injury rate for braced players in every position and string. During games, there was also a reduced rate for linemen and the linebacker/tight end group. The study concluded that although the issue is not closed, preventive knee braces appear to offer some protection to the medial collateral ligament from a contact injury involving a valgus blow, but there may be negative effects on performance level, leg cramping, and fatigue symptoms.

Use of discretionary protective equipment and rate of lower extremity injury in high school athletes

Use of protective equipment is an important sports injury prevention strategy, yet use of protective equipment by high school athletes has seldom been studied. The authors analyzed data from a 3-year (1996-1999), stratified, two-stage cluster sample of athletes from 12 organized sports in 100 North Carolina high schools (n = 19,728 athlete-seasons). Information on each athlete's use of protective equipment and prior injury was collected during the preseason. Prospective information on injuries and weekly participation in games and practices was collected during the playing season. Use of lower extremity discretionary protective equipment tended to decrease the overall rate of lower extremity injury (rate ratio (RR) = 0.91, 95% confidence interval (CI): 0.72, 1.15). However, this slight protective effect was entirely due to kneepad use (for knee injury, RR = 0.44, 95% CI: 0.27, 0.74). Knee brace use and ankle brace use were associated with increased rates of knee injury (RR = 1.61, 95% CI: 1.08, 2.41) and ankle injury (RR = 1.74, 95% CI: 1.11, 2.72), respectively. This could be due to slippage of the brace during use, increased fatigue due to the energy cost of wearing a brace, or bias in the study. Further investigation into the effects of brace use is warranted.

Place des orthèses en pathologie ligamentaire du genou. Revue de la littérature

OBJECTIVE

To review the literature for the benefits of the three different knee braces (prophylactic, rehabilitation, functional) that can be used to treat ligament injuries of the knee. What is their influence on stability? Do they have adverse effects? Is their use justified?

METHODS

We searched the Medline and Embase databases with use of the keywords knee, orthoses, brace, proprioception, stability, rehabilitation, physical therapy, and anterior cruciate ligament for reports published between 1980 and 2003 and selected 93 articles, expert reports or literature reviews.

RESULTS

Anterior tibial displacement can be controlled with mechanical strains (150 N), which are lower than physiological restraints? (400 N). The control of joint position is improved by increasing proprioception. Soft tissue stiffness influences the control of anterior tibial displacement. The beneficial effects observed are mainly subjective. Our analysis of the literature showed limitations and variations in study methodologies.

CONCLUSION

We did not find any justification for use of either prophylactic or rehabilitation braces. Functional braces can improve stability, as reported by the patient, and may be used in some situations.