Functional Knee Brace Research Articles

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.

Effect of Functional Knee Brace and Lateral Wedge Insole in Management of Patients with Osteoarthritic Knee

Chao Jung Hsieh, Fen Ling Kuo, Sai Wei Yang and Lin Fen Hsieh 4 1 Institute of Rehabilitation Science and Technology, National Yang-Ming University, Taipei, Taiwan 2 Department of Rehabilitation, Taipei Municipal Wanfang Hospital, Taipei, Taiwan 3 Institute of Biomechanical Engineering, National Yang-Ming University, Taipei, Taiwan Department of Rehabilitation, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan web: http://rehab.ym.edu.tw/

Effect of Functional Bracing on Knee Injury in Skiers with Anterior Cruciate Ligament Reconstruction

Background The role of knee bracing in anterior cruciate ligament reconstructions is controversial. Hypothesis Functional bracing will have an effect on subsequent knee injury in skiers with anterior cruciate ligament reconstruction. Study Design Cohort study; Level of evidence, 3. Methods From 1991 to 1997, 11606 skiers at a major destination ski resort underwent preseason knee screening. The anterior cruciate ligamentreconstructed group consisted of 820 skiers who had had an anterior cruciate ligament reconstruction 2 years or more earlier. Of these, 257 skiers selected the use of functional knee brace during skiing. The dependent variable was subsequent knee injury, identified via workers compensation records. Covariates included age, gender, ski occupation, Lachman grade, pivot-shift grade, KT-1000 arthrometer manual maximum displacement, and use of a functional brace. Univariate and multivariate risk factors for subsequent knee injury were determined. Results In this study, 257 skier-employees with anterior cruciate ligament reconstruction wore braces and 563 skier-employees with anterior cruciate ligament reconstruction did not. Braced skiers had significantly higher preseason rates of grade II or higher Lachman and pivot-shift tests (braced, 29% and 22%, respectively; nonbraced, 11% and 10%, respectively;P >. 05). Sixty-one subsequent knee injuries were identified, 51 (8.9 injuries/100 knees/ski season) in the nonbraced group and 10 (4.0 injuries/100 knees/ski season) in the braced group (P=. 009). Nonbraced skiers were 2.74 times more likely to suffer subsequent injury than were braced skiers (odds ratio, 2.74 [confidence interval, 1.2-4.9]). Logistic regression modeling identified nonbracing as a significant independent multivariate risk factor for subsequent knee injury in the high-demand skiers with anterior cruciate ligament reconstruction. Conclusion Because of the increased risk of subsequent knee injury in nonbraced skiers, the authors recommend functional bracing for skiers with anterior cruciate ligament reconstruction. Whether the protective effect of functional bracing can be extrapolated to other high-demand patients is yet to be determined.

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.

Study on three-dimensional kinematics and electromyography of ACL deficient knee participants wearing a functional knee brace during running

This investigation examined the muscular activity and 3D knee joint kinematic changes of anterior cruciate ligament-deficient (ACLD) participants in the involved leg under bracing condition during running. Different adaptation strategies have been found between patients who can cope with the injury and patients who cannot. One of the expected changes can be the muscle activation characteristic of the injured knee during strenuous activity with and without a functional knee brace. Three-dimensional kinematic and electromyographical (EMG) data were collected from 11 participants for 10 consecutive gait cycles during running on a treadmill under both braced and unbraced conditions. Participants were administered the "Knee Outcome Survey Activities of Daily Living Scale" to distinguish functional and non-functional candidates. No significant differences on 3D kinematics and EMG data were noted between functional and non-functional participants, thus data analysis focused on comparisons of bracing conditions for one combined group. Bracing significantly reduced total range of motion in the frontal and transverse planes (P<0.05). Muscle activity at heel-strike showed a consistent trend to increase for the hamstrings and decrease for the quadriceps under the braced condition when compared to the unbraced condition. Our findings indicate that bracing the ACLD knee alters the kinematics of the injured leg while running. Tendencies toward reductions in quadriceps and increases in hamstrings activity at heel-strike indicate that bracing might have resulted in added stability of the injured knee. The adaptations to bracing found in this preliminary study further support the potential mechanical and proprioceptive contributions of the functional knee brace to protect the ACLD knee.

Influence of functional bracing on the kinetics of anterior cruciate ligament-injured knees during level walking

Use of functional knee braces has been suggested to provide protection and to improve kinetic performance of the knee in anterior cruciate ligament-injured patients. However, the efficacy of knee bracing in achieving these goals is still controversial. The purpose of this study was to examine the immediate effects of functional bracing on the three-dimensional kinetics of the knee in individuals with anterior cruciate ligament injuries during level walking. Fifteen anterior cruciate ligament-deficient and 15 anterior cruciate ligament-reconstructed subjects were each fitted with a DonJoy Goldpoint brace and walked at a self-selected pace, first without and then with the brace. Kinematic and kinetic data were measured and three-dimensional joint moments and angular impulses at the knee were calculated and compared between bracing conditions and between limbs. Functional knee bracing did not significantly affect the kinetics of the unaffected knees for either group. Bracing significantly increased the peak abductor moments in anterior cruciate ligament-deficient knees and reduced the bilateral kinetic asymmetry in the coronal plane. For the anterior cruciate ligament-reconstructed group, bracing increased peak moments and impulses of the abductors and extensors. It also reduced bilateral kinetic asymmetry in the sagittal and coronal planes. Effects of the knee brace were apparent in the coronal plane for both anterior cruciate ligament-deficient and anterior cruciate ligament-reconstructed patients, and in the sagittal plane for anterior cruciate ligament-reconstructed patients. Functional bracing can be recommended for anterior cruciate ligament-reconstructed patients to assist in achieving better bilateral kinetic symmetry during gait. For anterior cruciate ligament-deficient patients, apart from bracing, additional emphasis on the rehabilitative training for better kinetic knee performance in the sagittal plane is needed.

In Vivo Three-Dimensional Determination of the Effectiveness of the Osteoarthritic Knee Brace: A Multiple Brace Analysis

P revious kinematic studies on the effects of knee braces have concentrated primarily on the anterior cruciate ligament and the effects of bracing to stabilize the knee that has a deficiency of this ligament1-23. The majority of those studies have concentrated on the analysis of functional knee braces with use of arthrometers2,3,5-8,10-15. Other studies have concentrated on the analysis of femorotibial translation through the use of roentgen stereophotogrammetric analysis techniques4,9,16,17, subjective evaluation of bracing by categorizing pain and functional ability18-22, and the determination of the effectiveness of different types of knee braces, such as cast bracing23-26. Although minimal research evaluating the efficiency of off-loading braces for the treatment of unicompartmental arthritic degeneration has been performed, a previous study with an initial fluoroscopic analysis determined that bracing is an effective treatment for osteoarthritis of the knee in nonobese patients under weight-bearing conditions27. In that investigation of a single type of brace, the results were not assessed for three-dimensional motion and the study did not determine whether different types of osteoarthritic knee braces would perform well under similar conditions. The objective of the present study was to analyze subjects with symptomatic unicompartmental osteoarthritis under in vivo, dynamic weight-bearing conditions with use of video fluoroscopy28,29 to determine whether five different off-loading knee braces provide separation of the medial femoral condyle from the tibial plateau, thus avoiding excessive loads on the degenerated compartment. Fig. 1 Subject performing normal gait on a treadmill without a brace ( a ) and with a brace ( b ). W ith institutional review board approval, five subjects with substantial medial compartment osteoarthritis of the knee who …

164 Adaptation to wearing a functional knee brace: a possible step in preventing knee injuries: a pilot study

164 Adaptation to wearing a functional knee brace: a possible step in preventing knee injuries: a pilot study

The Effects of a Functional Knee Brace During Early Treatment of Patients With a Nonoperated Acute Anterior Cruciate Ligament Tear

To evaluate the effect of a functional knee brace on nonoperated acute anterior cruciate ligament (ACL)-deficient patients. : Prospective randomized clinical trial. University clinic. Ninety-five patients (18-50 years old) with an acute ACL tear were included in the present study. The subjects were randomized to either brace group, treated with functional bracing from the first testing session (<5 weeks postinjury) to 12 weeks postinjury or a control group, treated without bracing. The patients were followed for 6 months. Twenty-one subjects were excluded due to the following exclusion criteria: partial rupture or articular cartilage injury shown on MRI or with arthroscopy, or other injuries that negatively affected rehabilitation, or dropped out due to surgery (n = 22), or personal reasons (n = 10). Forty-two patients remained in the study, 22 in the brace group and 20 in the control group. Visual analogue scale, Knee Osteoarthritis Outcome Score, Cincinnati knee score, a brace evaluation form, and muscle peak torque. When using the brace the subjects in the brace group experienced less (P = 0.047) sense of instability, evaluated with visual analogue scale, than the control group. However, bracing had no effect on any of the variables in Knee Osteoarthritis Outcome Score or Cincinnati knee score and no effect on quadriceps or hamstring muscle peak torque. Subjectively, the brace group experienced a positive effect of the brace on rehabilitation. Nonoperated acute ACL-deficient patients experienced a positive effect of the brace regarding sense of instability and rehabilitation. However, these findings were not supported by objective outcomes.

Anterior Cruciate Ligament Tear Prevention in the Female Athlete

Anterior Cruciate Ligament Tear Prevention in the Female Athlete

Functional Bracing after Anterior Cruciate Ligament Reconstruction

Background Bracing after anterior cruciate ligament reconstruction is expensive and is not proven to prevent injuries or influence outcomes. Purpose To determine whether postoperative functional knee bracing influences outcomes. Study Design Prospective, randomized, multicenter clinical trial. Methods One hundred volunteers from the 3 US service academies with acute anterior cruciate ligament tears were randomized into braced or nonbraced groups. Only those subjects with anterior cruciate ligament tears treated surgically within the first 8 weeks of injury were included. Patients with chondral injuries, significant meniscal tears, or multiple knee ligament injuries were excluded. Surgical procedures and the postoperative physical therapy protocols were identical for both groups. The braced group was instructed to wear an off-the-shelf functional knee brace for all cutting, pivoting, or jumping activities for the first year after surgery. Results Ninety-five subjects were available with a minimum 2-year follow-up. There were no statistically significant differences between groups in knee stability, functional testing with the single-legged hop test, International Knee Documentation Committee scores, Lysholm scores, knee range of motion, or isokinetic strength testing. Two braced subjects had reinjuries, and 3 nonbraced subjects had reinjuries. Conclusions In this young, active population, postoperative bracing does not appear to change the clinical outcomes after anterior cruciate ligament reconstruction.

Active Patellar Tracking Measurement

Background Many patients suffer patellar instability that may relate to transient patellar tracking abnormalities. Objective To develop and test a technique to measure dynamic patellar tracking. Study Design Controlled laboratory and in vivo study. Method A functional knee brace was modified to allow an ultrasound transducer to be mounted laterally to the femur, following the path of the patella during knee movement. An ultrasound system was used to measure patellar mediolateral position parallel to the femoral transepicondylar axis. Ten subjects with no patellar instability were studied to obtain patellar tracking and accuracy data. Results The interobserver and intraobserver reproducibility ranged from 0.2 ± 0.1 mm to 1.0 ± 0.5 mm. The accuracy of the ultrasound measurement was checked against magnetic resonance imaging and was 0.6 ± 1.9 mm. The patella moved medially then laterally from extension to flexion when sitting. Squatting and stepping produced a more lateral path, without the initial medial translation. The patella was more lateral during knee extension than during flexion. Conclusions This novel method for measurement of dynamic patellar mediolateral tracking was found to have good intraobserver and interobserver reproducibility, and the measurements matched closely with those obtained from magnetic resonance imaging reconstructions of static patellar positions. Some preliminary data for tracking in 3 activities were obtained from 10 normal knees.

The Role of Functional Knee Braces in Managing ACL Injuries

The Role of Functional Knee Braces in Managing ACL Injuries

Effects of functional knee bracing on muscle-firing patterns about the chronic anterior cruciate ligament-deficient knee

Smith J, Malanga GA, Yu B, An K-N. Effects of functional knee bracing on muscle-firing patterns about the chronic anterior cruciate ligament-deficient knee. Arch Phys Med Rehabil 2003;84:1680–6. Objective To examine the effects of functional knee bracing on the muscle-firing patterns about the chronic anterior cruciate ligament (ACL)-deficient knee in successful brace users. Design Cross-sectional comparative clinical trial. Setting Motion analysis laboratory. Participants Ten active individuals with unilateral, isolated, chronic (>18mo postinjury), ACL-deficient knees who subjectively reported improved function with a functional knee bracing. Intervention Each subject completed 3 single-leg hop maneuvers on their ACL-deficient knee with and without their knee brace while surface electromyographic activity was recorded from the quadriceps, hamstring, and gastrocnemius muscles. Main outcome measure Muscle onset latency. Results Brace use significantly delayed the average onset of vastus lateralis activation before landing (123±47ms vs 109±30ms, P<.001), though significant interindividual variations existed. Bracing significantly altered the onset latency in 1 or more muscles in 9 of 10 subjects. In 4 subjects, a favorable change in the firing pattern was seen, whereas only 1 subject exhibited an unfavorable change. Without bracing, 5 of the 10 subjects fired the hamstrings or gastrocnemius muscles first; with bracing, 7 of 10 fired these muscles first. Conclusions Brace use in this population did not consistently result in more favorable muscle firing patterns during the single-leg hop maneuver. Interindividual responses to brace use indicate the need for further research to investigate the multiple strategies that may exist to stabilize the ACL-deficient knee. In the meantime, functional knee brace use among ACL-deficient patients remains empirical.

Ruptur des Ligamentum patellae als Begleitläsion komplexer Kniebandverletzungen

A case in which a 28-year-old female skier simultaneously ruptured the patellar tendon, anterior cruciate ligament (ACL), medial collateral ligament (MCL) and medial meniscus during a skiing injury is reported. Primary repair of the patellar tendon, reconstruction of the MCL, arthroscopic repair of the ACL and the medial meniscus was performed at the same time of surgery. A functional knee brace with limited range of motion was used for the postoperative rehabilitation program. At follow-up, 5 month after surgery, the patient had full range of knee motion, no ligamentous instability and a good quadriceps muscle function.

Electromyographic and biomechanic analysis of anterior cruciate ligament deficiency and functional knee bracing

Objective. Examine the neuromuscular response to functional knee bracing relative to anterior tibial translations in vivo. Design. During randomised brace conditions, electromyographic data with simultaneous skeletal tibiofemoral kinematics were recorded from four anterior cruciate ligament deficient subjects to investigate the effect of the DonJoy Legend functional brace during activity. Background. Knee braces do not increase knee stability but may influence afferent inputs from proprioception and therefore one might expect changes in muscle firing patterns, amplitude and timing. Methods. Hoffman bone pins affixed with markers were implanted into the tibia and femur for kinematic measurement. The EMG data from the rectus femoris, semitendinosus, biceps femoris, and lateral head of the gastrocnemius were integrated for each subject in three separate time periods: 250 ms preceding footstrike and two consecutive 125 ms time intervals following footstrike. Results. With brace, semitendinosus activity significantly decreased 17% prior to footstrike whereas bicep femoris significantly decreased 44% during A2, ( P<0.05). Rectus femoris activity significantly increased 21% in A2 ( P<0.05). No consistent reductions in anterior translations were evident. Conclusion. Our preliminary findings, based on a limited number of subjects, indicate joint stability may result from proprioceptive feedback rather than the mechanical stabilising effect of the brace. Despite a significant increase in rectus femoris activity upon landing, only one subject demonstrated an increase in anterior tibial drawer. Relevance Studies have shown functional braces do not mechanically stabilise the anterior cruciate ligament deficient knee. Perhaps bracing alters proprioceptive feedback. It has been shown that bracing the anterior cruciate ligament deficient knee may affect hamstring and quadriceps activity. Our findings stresses the importance of functional knee bracing combined with proprioceptive and muscular coordination training in order to increase joint stability.

Effect of a functional knee brace on knee flexion and extension strength after anterior cruciate ligament reconstruction

Birmingham TB, Kramer JF, Kirkley A. Effect of a functional knee brace on knee flexion and extension strength after anterior cruciate ligament reconstruction. Arch Phys Med Rehabil 2002;83:1472-5. Objectives: To investigate the effect of a knee brace on knee flexion and extension muscular strength of patients after anterior cruciate ligament (ACL) reconstruction and to evaluate whether the effect of the brace depends on patient symptoms and muscular strength. Design: Repeated measures. Setting: A university-based outpatient orthopedic clinic and musculoskeletal assessment laboratory. Participants: Twenty-seven patients (14 women, 13 men; mean age, 28±11y) having undergone arthroscopically assisted ACL reconstruction by using a semitendinosus and gracilis autograft. Intervention: A custom-fit ACL functional knee brace. Main Outcome Measures: The brace effect was calculated as the change in peak torque observed with the brace, expressed as a percentage of peak torque observed without the brace, during isokinetic concentric knee flexion and extension movements performed at 90°/s. Patient symptoms were quantified by using a disease-specific health-related quality of life questionnaire. Results: Knee flexion strength decreased significantly with the brace (mean brace effect=−7.3%, P<.05). The brace effect during knee flexion varied considerably (−52% to 47%) and was significantly related to peak torque observed without the brace (r=−.50, P<.01). All other comparisons and correlations were not significant. Conclusions: These findings suggest that brace effects depend on patient strength. A brace may inhibit knee flexion strength of stronger patients, yet result in no change or even improvements in strength of weaker patients. Future research is required to further elucidate which patients may derive most benefit or detriment from bracing. © 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Does wearing a functional knee brace affect hamstring reflex time in subjects with anterior cruciate ligament deficiency during muscle fatigue?

Lam RY, Ng GY, Chien EP. Does wearing a functional knee brace affect hamstring reflex time in subjects with anterior cruciate ligament deficiency during muscle fatigue? Arch Phys Med Rehabil 2002;83:1009-12. Objective: To evaluate the effects of wearing a functional knee brace and muscle fatigue on hamstring reflex time in subjects with anterior cruciate ligament (ACL) deficiency. Design: Repeated-measures clinical trial. Setting: Outpatient physical therapy department. Participants: Sixteen subjects with ACL deficiency. Intervention: Subjects tested with and without a functional knee brace before and after an exercise protocol designed to fatigue the knee muscles. Main Outcome Measure: Latency of hamstring reflex muscle activity after sudden perturbation of the knee. Results: Wearing a knee brace shortened the hamstring reflex latency regardless of fatigue (F1,15=20.62, P<.001). Muscle fatigue lengthened the hamstring reflex time regardless of the bracing condition (F1,15=7.57, P<.015). Conclusion: Wearing a functional knee brace facilitated hamstring muscle reflex, but muscle fatigue lengthened the hamstring reflex latency. Subjects with ACL deficiency should not rely on the knee brace to facilitate hamstring reflex for joint protection during prolonged sporting activities when muscles are fatigued. © 2002 by the American Congress of Rehabilitation Medicine and the American Academy of physical Medicine and Rehabilitation

Use of Functional Knee Braces after ACL Reconstruction

Use of Functional Knee Braces after ACL Reconstruction

Knee Stability Controlled by Hamstrings and Functional Knee Brace

The purpose of this study was to determine the effectiveness of an off-the-shelf functional knee brace on preventing anterior tibial translation in anterior cruciate ligament-deficient knees (ACL-d) with greater than 6 mm of side-to-side difference, and the effect of a 50% maximal voluntary hamstring contraction on knee joint laxity. A therapist experienced in using the Knee Signature System (KSS) screened 14 patients who had been diagnosed arthroscopically with ACL deficiency. Nine patients (8 men, 1 woman; mean age, 32.9 years; mean mass, 75 kg; mean height, 177 cm) met the inclusion criteria. All participants were 240 ± 42 days post injury. Participants in the study were tested with no brace, with brace, and 50% maximal voluntary contraction (MVC) of the hamstrings. The uninjured limb was tested only in the unbraced condition. Repeated measures ANOVA (p ≤ .05) and a Bonferroni post hoc analysis was used to detect specific differences between conditions. Results indicate that a 50% hamstring contraction provided better control of anterior tibial displacement than a functional knee brace under the same loading conditions, but a brace may contribute significantly to reducing anterior displacement when the hamstring force is not sufficient.