Assessment of functional knee bracing: an in vivo three-dimensional kinematic analysis of the anterior cruciate deficient knee

OBJECTIVE: To describe three-dimensional tibial and femoral movements in vivo and examine the effect of a brace on knee kinematics during moderate to intense activity. DESIGN: Skeletal kinematics of anterior cruciate ligament deficient knees was measured with and without braces during moderate to intense activity. BACKGROUND: Invasive markers implanted into the tibia and femur are the most accurate means to directly measure skeletal motion and may provide a more sensitive measure of the differences between brace conditions. METHODS: Steinmann traction pins were implanted into the femur and tibia of four subjects having a partial or complete anterior cruciate ligament rupture. Non-braced and braced conditions were randomly assigned and subjects jumped for maximal horizontal distance to sufficiently stress the anterior cruciate ligament. RESULTS: Intra-subject peak vertical force and posterior shear force were generally consistent between conditions. Intra-subject kinematics was repeatable but linear displacements between brace conditions were small. Differences in angular and linear skeletal motion were observed across subjects. Bracing the anterior cruciate ligament deficient knee resulted in only minor kinematic changes in tibiofemoral joint motion. CONCLUSION: In this study, no consistent reductions in anterior tibial translations were observed as a function of the knee brace tested. Relevance. Investigations have reported that knee braces fail when high loads are encountered or when load is applied in an unpredictable manner. Questions remain regarding tibiofemoral joint motion, in particular linear displacements. The pin technique is a means for direct skeletal measurement and may provide a more sensitive measure of the differences between brace conditions.     

Influence of a mono-centric knee brace on the tension of the collateral ligaments in knee joints after sectioning of the anterior cruciate ligament--an in vitro study

OBJECTIVE: To analyze the influence of knee bracing on the tension of the medial and lateral collateral ligaments in anterior cruciate ligament deficiency. DESIGN: The tension of the collateral ligaments in anterior cruciate ligament deficient knees was measured with and without knee bracing using an in vitro model. BACKGROUND: Anterior cruciate ligament deficiency increases the tension in both collateral ligaments at the knee joint. Therefore knee braces should reduce that tension increase. However, that effect has never been proven quantitatively. METHODS: After anterior cruciate ligament-transection, the forces of the medial (anterior/posterior part) and lateral collateral ligament were measured in ten fresh human cadaver knees at 0 degrees, 20 degrees, 40 degrees, 60 degrees, 80 degrees and 100 degrees of flexion, with and without application of a mono-centric knee brace. To quantify the ligament forces, strain gauges were fixed at the bony origins of the ligaments. RESULTS: Bracing led to a significant decrease of ligament forces (20-100 degrees: P < 0.0001) in the anterior part of the medial collateral ligament in all joint positions. In the posterior aspect, this effect was observed only at 40 degrees (P < 0.0001) and 80 degrees (P = 0.001) of flexion. In the lateral collateral ligament, bracing caused a strain reduction from 60 degrees to 100 degrees of flexion (P < 0.0001). Therefore a flexion angle dependent effect of knee bracing on the strain was seen in the posterior aspect of the medial and in the lateral collateral ligament in anterior cruciate ligament deficient knee joints. CONCLUSIONS: Application of a mono-centric knee brace leads to a significant position dependent reduction of collateral ligament tension after anterior cruciate ligament-rupture.     

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

BACKGROUND: 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. METHODS: 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. FINDINGS: 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. INTERPRETATION: 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.     

Effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction

[Purpose] This study examined the effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction. [Subjects and Methods] The subjects were 16 adults who underwent arthroscopic anterior cruciate reconstruction and neuromuscular training. The Lysholm scale was used to assess functional disorders on the affected knee joint. A KT-2000 arthrometer was used to measure anterior displacement of the tibia against the femur. Surface electromyography was used to detect the muscle activation of the vastus medialis oblique, vastus lateralis, biceps femoris, and semitendinosus before and after neuromuscular training. [Results] There was significant relaxation in tibial anterior displacement of the affected and sound sides in the supine position before neuromuscular training. Furthermore, the difference in the tibial anterior displacement of the affected knee joints in the standing position was reduced after neuromuscular training. Moreover, the variation of the muscle activation evoked higher muscle activation of the vastus medialis oblique, vastus lateralis, biceps femoris, and semitendinosus. [Conclusion] Neuromuscular training may improve functional joint stability in patients with orthopedic musculoskeletal injuries in the postoperative period.Key words: Arthrometer, Anterior cruciate ligament reconstruction, Neuromuscular training     

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.     

Role of orthoses in ligament injuries of the knee]

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.     

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

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 MEASURES: 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.     

Association between Femoral Anteversion and Lower Extremity Posture upon Single-leg Landing: Implications for Anterior Cruciate Ligament Injury

[Purpose] Increased femoral anteversion may occur with hip internal rotation and valgus knee alignment upon landing and is considered a risk factor for anterior cruciate ligament injury. We examined the relationship between femoral anteversion and joint motion and muscle activity of the lower extremity in terms of the risk factors for anterior cruciate ligament injury. [Subjects] Sixteen healthy females were divided on the basis of femoral anteversion into low and high groups. [Methods] Femoral anteversion was assessed using Craig''s test. We performed kinematic analysis and measured the electromyography activity of the lower extremity upon left single-leg landing. [Results] The high group had a significantly lower hip flexion angle and higher knee flexion and valgus angles than the low group. The rectus femoris showed significantly greater electromyography activities in the high group than in the low group. [Conclusion] These results suggest that increased femoral anteversion results in lower hip flexion angle, higher knee valgus alignment, and greater rectus femoris muscle activity, leading to anterior tibial displacement upon single-leg landing. Increased femoral anteversion may be a potential risk factor for anterior cruciate ligament injury.Key words: Femoral anteversion, Lower extremity alignment, Single-leg landing     

Effect of hamstrings muscle action on stability of the ACL-deficient knee in isokinetic extension exercise

Objective. To quantify the effect of hamstrings muscle action on stability of the anterior cruciate ligament deficient knee during isokinetic exercise at various speeds.

Design. Mathematical modeling and forward-dynamics computer simulation were used to study the interactions between knee-extension speed, hamstrings co-contraction activity, and anterior tibial translation in the intact and anterior cruciate deficient knee.

Background. There is much experimental evidence available to believe that hamstrings co-contraction can reduce anterior tibial translation in the anterior cruciate deficient knee. Little is known, however, about the level of hamstrings activation needed to keep anterior tibial translation within normal limits during functional activity.

Methods. Isokinetic knee-extension was simulated with a sagittal-plane model used previously to study load sharing between the muscles, ligaments, and bones during isometric knee-extension exercise, isokinetic exercise, and squatting exercise.

Conclusions. Some amount of hamstrings activation is needed to stabilize an anterior cruciate deficient knee irrespective of how fast the knee extends. The level of hamstrings co-contraction needed to stabilize an anterior cruciate deficient knee is inversely related to extension speed. Hamstrings co-contraction is more effective in reducing anterior tibial translation than low-resistance extension exercise.Relevance

Excessive anterior tibial translation during knee-extension exercise may lead to damage of the meniscus and other passive structures inside the knee. If anterior cruciate deficient patients can be trained to co-contract their hamstrings during isokinetic knee-extension, then this exercise is appropriate for maintaining strength of the thigh muscles without compromising the anterior stability of the knee.     

股直肌腱中1/3与前交叉韧带的生物力学比较

背景:股直肌腱已成为重建前交叉韧带的重要替代物。目的:比较股直肌腱中1/3和前交叉韧带的生物力学特性。方法:标本于死者死亡后9.0~10.0h解剖取下股直肌腱和前交叉韧带,取下后立刻用以生理盐水浸湿的纱布包裹,密封后置于-20℃冰箱内保存。实验前取出标本,切取试样,股直肌腱和前交叉韧带每组共10个试样。结果与结论:股直肌腱中1/3的单位模量是前交叉韧带的63%,单位最大载荷为63%,提示股直肌腱中1/3是适合作为交叉韧带重建物的。     

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

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 (F(1,15)=20.62, P<.001). Muscle fatigue lengthened the hamstring reflex time regardless of the bracing condition (F(1,15)=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.     

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

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+/-11 y) 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 degrees /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.     

Effect of functional bracing, quadriceps and hamstrings on anterior tibial translation in anterior cruciate ligament insufficiency: a preliminary study.

Anterior tibial translation was measured in six patients with anterior cruciate ligament insufficiency. The tests were done in 15, 45, and 90 degrees of knee flexion, partly with activated quadriceps or hamstrings, and partly with subjects wearing a 4-point functional DonJoy brace. The translation was evaluated with a computerized electrogoniometer (Acufex KSS). The anterior tibial translation was significantly reduced by use of the hamstrings in all three degrees of knee flexion. The effect of the 4-point brace was only significant in 15 and 45 degrees of flexion. The quadriceps did not reduce the anterior tibial translation.     

Wear patterns on tibial plateau from varus osteoarthritic knees

BACKGROUND: The knowledge of cartilage wear patterns at the medial tibial plateau is important to understand the main causes of arthritis in varus knees. The most important factors influencing knee arthritis in fact seem to be the severity of the degenerative changes determined by the lower limb mechanical axis and the abnormal knee joint kinematics which frequently results from dysfunction of the anterior cruciate ligament. METHODS: We studied the wear patterns of cartilage damage in 70 medial tibial plateaus resected at operation during total knee arthroplasty indicated for varus osteoarthritic knee. Anterior cruciate ligament and medial meniscus integrity was assessed intra-operatively. Calibrated digital images were used to measure the wear patterns with a standard software tool. The medial compartment of the tibial plateau was divided into six zones, and the amount of cartilage and bone destruction in each zone was classified into two grades. FINDINGS: The wear pattern was found to be highly dependent upon knee varus deformity (Mann Whitney P<0.001) and anterior cruciate ligament integrity (Friedman P<0.0005). Anterior cruciate ligament was found intact in 35.7% of the cases. Wear patterns on intact anterior cruciate ligament knees occurred in the central to medial aspect of the tibial plateau. Anterior cruciate ligament deficient knees had significantly larger wear patterns anteriorly and posteriorly in the most medial region of the medial plateau. INTERPRETATION: These observations suggest altered joint mechanics exist in anterior cruciate ligament deficient varus knees, which would worsen cartilage degeneration and osteoarthritis progression.     

In vivo kinematics of anterior cruciate ligament deficient knees during pivot and squat activities

Background

Knee kinematics during pivoting activities are not well studied, but might provide insight critical to understanding the pathology of the anterior cruciate ligament deficient knee. The purpose of this study was to compare in vivo kinematics during weight bearing pivot and squat activities in patients with unilateral anterior cruciate ligament deficient knees, and to contrast those kinematics with the uninjured contralateral knees.

Methods

Eight unilateral anterior cruciate ligament deficient patients with a mean age of 41 (SD 7) years were enrolled. Anterior cruciate injury was confirmed by positive Lachman test and MRI. Lateral fluoroscopic images of pivot and squat activities were recorded for both anterior cruciate ligament deficient and contralateral knees. Three-dimensional tibiofemoral kinematics and centers of rotation for each knee were determined using 3D–2D model registration techniques.

Findings

During pivoting, the tibia of the anterior cruciate ligament deficient knee was significantly more anterior than the contralateral knee during tibial neutral to internal rotation. The pivot activity showed lateral centers of rotation in both anterior cruciate ligament deficient and contralateral knees while squatting showed medial centers of rotation.

Interpretation

This dynamic method might be useful to objectively characterize restoration of dynamic function in knees with various types of anterior cruciate ligament reconstructions. These results also indicate kinematics during squatting type activities cannot be extrapolated to predict knee kinematics during pivoting types of activities.     

双骨道与三骨道前交叉韧带双束重建的生物力学比较

背景:关节镜下前交叉韧带重建可以有效地解决前交叉韧带损伤引起的膝关节不稳症状,而双骨道(胫骨单骨道-股骨单骨道)与三骨道(胫骨单骨道-股骨双骨道)前交叉韧带重建是目前较为常用的重建方式。目的:探讨双骨道与三骨道前交叉韧带双束重建对膝关节稳定性的影响。方法:选用8具新鲜正常成人尸体膝关节标本,分别进行双骨道与三骨道前交叉韧带双束重建,然后在MTS-809生物力学测试系统上测试膝关节在胫前加载(134N)以及胫骨旋转加载(5Nm内旋)下屈曲0°,15°,30°,60°,90°时的膝关节稳定性。结果与结论:①胫前加载:在所测的5个角度下,两重建组的胫前位移较前交叉韧带完整组均增大,但差异无显著性意义(P>0.05);双骨道重建组较三骨道重建组胫前位移增大,但差异无显著性意义(P>0.05)。②旋转加载:在所测的5个角度下,前交叉韧带完整组的胫前位移最小,双骨道重建组与三骨道重建组比较,在膝关节屈曲0°,15°和90°时,差异无显著性意义(P>0.05),在膝关节屈曲30°和60°时,三骨道重建组胫前位移小于双骨道重建组,差异有显著性意义(P<0.05);三骨道重建组与前交叉韧带完整组比较,差异无显著性意义(P>0.05)。提示双骨道与三骨道前交叉韧带双束重建均可促进膝关节前后及旋转稳定性的恢复,三骨道前交叉韧带双束重建与双骨道前交叉韧带双束重建相比,显示了更好恢复膝关节旋转稳定性的作用。     

Gait of subjects with anterior cruciate ligament deficiency

An inter-limb comparison of ten subjects with unilateral anterior cruciate ligament (ACL) deficiency was undertaken in several areas. Isokinetic muscle testing was carried out at joint angular velocities of 60, 180 and 300/s. Each subject was videotaped at 200 Hertz while running on a treadmill at a recreational jogging pace, and kinematics were calculated. Electromyographic data were collected from the vasti lateralis and biceps femoris muscles during running. Isokinetic muscle testing revealed a significant quadriceps deficit in the ACL-deficient limb. During jogging, normalized electromyographic profiles showed increased quadriceps activity during a 200 ms period centred on footstrike. Earlier electromyographic activity was observed from the biceps femoris of the ACL-deficient limbs shortly after footstrike. It was concluded that even during straight line running, an activity not usually thought to affect individuals with ACL deficiency, compensatory techniques may be observed.     

Dynamic Restraint Capacity of the Hamstring Muscles Has Important Functional Implications After Anterior Cruciate Ligament Injury and Anterior Cruciate Ligament Reconstruction

Bryant AL, Creaby MW, Newton RU, Steele JR. Dynamic restraint capacity of the hamstring muscles has important functional implications after anterior cruciate ligament injury and anterior cruciate ligament reconstruction.

Objective

The purpose of this study was to investigate the relation between knee functionality of anterior cruciate ligament deficient (ACLD) and anterior cruciate ligament reconstruction (ACLR) patients and hamstring antagonist torque generated during resisted knee extension.

Design

Cross-sectional.

Setting

Laboratory based.

Participants

Male ACLD subjects (n=10) (18–35y) and 27 matched males who had undergone ACLR (14 patella tendon [PT] grafts and 13 combined semitendinosus/gracilis tendon grafts).

Interventions

Not applicable.

Main Outcome Measures

Knee functionality was rated (0- to 100-point scale) by using the Cincinnati Knee Rating System. Using electromyography data from the semitendinosus (ST) and biceps femoris muscles, we created a mathematical model to estimate the opposing torque generated by the hamstrings during isokinetic knee extension in 10° intervals from 80° to 10° knee flexion.

Results

Pearson product-moment correlations revealed that more functional ACLD subjects generated significantly (P<.05) higher hamstring antagonist torque throughout knee extension. In contrast, more functional PT subjects produced significantly lower hamstring antagonist torque at 80° to 70° knee flexion, whereas no significant associations were found between hamstring antagonist torque and knee functionality for the ST/gracilis tendon subjects.

Conclusions

An increased hamstring antagonist torque generated by the more functional ACLD subjects, reflective of increased hamstring contractile force, is thought to represent a protective mechanism to compensate for mechanical instability. The restoration of anterior knee stability through ACLR negates the need for augmented hamstring antagonist torque.     

自体肌腱移植修复前交叉韧带合并后外侧角损伤

背景:自体半腱和股薄肌腱移植均可重建交叉韧带和膝关节后外侧角.目的:分析自体半腱和股薄肌腱移植修复膝关节前交叉韧带合并后外侧角损伤的效果.方法:将20例膝关节前交叉韧带合并后外侧角损伤患者随机分成两组:实验组在关节镜辅助下应用自体半腱肌、股薄肌一期重建前交叉韧带和加强重建后外侧角韧带;对照组仅采用自体组半腱肌、股薄肌一期重建前交叉韧带.结果与结论:两组术后Lysom评分较术前明显改善(P < 0.01).实验组患者在站立、行走和上下楼梯时无与膝关节后外侧不稳相关的过伸位膝关节不稳感,未发现行走时膝关节内甩;关节活动度屈曲100°～135°,伸直0°～10°.对照组中3例在站立,行走和上下楼梯时无与膝关节后外侧不稳相关的过伸位膝关节不稳感,4例行走时出现轻微膝关节内甩;关节活动度屈曲104°～130°,伸直0°～10°.说明用自体肌腱移植重建膝关节前交叉韧带和后外侧结构损伤,能够恢复膝关节后外侧与前后方的稳定性,较单纯重建前交叉韧带效果好.     

Influence of an unloader brace on lower limb electromyographic activity in individuals with predominant lateral osteoarthritis after anterior cruciate ligament reconstruction

ObjectiveTo determine the immediate effects of a varus unloader knee brace on lower-limb electromyographic activity in individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction.MethodsElectromyographic data were recorded in 19 individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction during walking under three conditions: (i) no brace, (ii) unadjusted brace (no varus adjustment), and adjusted brace (varus adjustment). Variables of interest were statistically analyzed using repeated measures analysis of variance.ResultsThere were no significant differences in muscle co-contraction between the three test conditions. The adjusted brace resulted in delayed offset of gluteus maximus (mean difference [95% CI]: 72 ms [24, 119]), and earlier onset of gluteus medius (59 ms [21, 97]) compared to no brace. The adjusted brace delayed onset of lateral gastrocnemius compared to no brace (53 ms [28, 78]) and the unadjusted brace (39 ms [7, 71]) and reduced average activation amplitude of gluteus maximus (−4 mV [−6, −1]) and lateral gastrocnemius (−9 mV [−16, −2]) compared to no brace.ConclusionsThe unloader brace did not produce significant changes in muscle co-contraction in individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction. Significant changes in gluteal and gastrocnemius muscle activation timing and amplitude were observed, however, it is not clear whether these changes are of clinical importance.