Biomechanical comparison of frontal plane knee joint moment arms during normal and Tai Chi walking

[Purpose] Medial knee osteoarthritis, a degenerative joint disease, affects adults. The external knee adduction moment, a surrogate knee-loading measure, has clinical implications for knee osteoarthritis patients. Tai Chi is a promising intervention for pain alleviation in knee osteoarthritis; however, the characteristics of external knee adduction moment during Tai Chi have not been established. [Subjects and Methods] During normal and Tai Chi walking, a gait analysis was performed to compare the external knee adduction moment moment-arm characteristics and paired t-tests to compare moment-arm magnitudes. [Results] A significant difference was observed in the average lateral direction of moment-arm magnitude during Tai Chi walking (−0.0239 ± 0.011 m) compared to that during normal walking (−0.0057 ± 0.004 m). No significant difference was found between conditions in average medial direction of moment-arm magnitude (normal walking: 0.0143 ± 0.010 m; Tai Chi walking: 0.0098 ± 0.014 m). [Conclusion] Tai Chi walking produced a larger peak lateral moment-arm value than normal walking during the stance phase, whereas Tai Chi walking and normal walking peak medial moment-arm values were similar, suggesting that medial knee joint loading may be avoided during Tai Chi walking.Key words: Tai Chi gait, External knee adduction moment arm, Walking     

Lateral wedge insoles for medial knee osteoarthritis: effects on lower limb frontal plane biomechanics

Background

Lateral wedges reduce the peak knee adduction moment and are advocated for knee osteoarthritis. However some patients demonstrate adverse biomechanical effects with treatment. Clinical management is hampered by lack of knowledge about their mechanism of effect. We evaluated effects of lateral wedges on frontal plane biomechanics, in order to elucidate mechanisms of effect.

Methods

Seventy three participants with knee osteoarthritis underwent gait analysis with and without 5° lateral wedges. Frontal plane parameters at the foot, knee and hip were evaluated, including peak knee adduction moment, knee adduction angular impulse, center of pressure displacement, ground reaction force, and knee-ground reaction force lever arm.

Findings

Lateral wedges reduced peak knee adduction moment and knee adduction angular impulse (− 5.8% and − 6.3% respectively, both P < 0.001). Although reductions in peak moment were correlated with more lateral center of pressure (r = 0.25, P < 0.05), less varus malalignment (r values 0.25-0.38, P < 0.05), reduced knee-ground reaction force lever arm (r = 0.69, P < 0.01), less hip adduction (r = 0.24, P < 0.05) and a more vertical frontal plane ground reaction force vector (r = 0.67, P < 0.001), only reduction in knee-ground reaction force lever arm was significantly predictive in regression analyses (B = 0.056, adjusted R² = 0.461, P < 0.001).

Interpretation

Lateral wedges significantly reduce peak knee adduction moment and knee adduction angular impulse. It seems a reduced knee-ground reaction force lever arm with lateral wedges is the central mechanism explaining their load-reducing effects. In order to understand why some patients do not respond to treatment, future evaluation of patient characteristics that mediate wedge effects on this lever arm is required.     

Influences of hamstring stiffness and strength on anterior knee joint stability

Background

Excessive anterior tibial translation is a prospective risk factor for anterior cruciate ligament injury, thus factors which limit this motion may reduce injury risk. Stiffness quantifies a muscle's resistance to lengthening, and stiffer hamstrings may resist changes in length induced by anterior tibial translation more effectively.

Methods

Anterior tibial translation, hamstring strength, and hamstring stiffness were assessed in 30 physically active volunteers. Simple correlations were used to evaluate relationships between stiffness, strength, and anterior tibial translation. Anterior tibial translation data were arranged into high and low groups based on the median value, and hamstring strength and stiffness were compared between these groups via t-tests.

Findings

Anterior tibial translation was correlated with hamstring stiffness (r = −0.538; P = 0.002), but not with hamstring strength (r = −0.088; P = 0.644). Hamstring stiffness and strength were not correlated (r = 0.054; P = 0.778). Hamstring stiffness was greater in the low anterior tibial translation group (t₂₈ = 2.186; P < 0.037; ES = 0.36), but hamstring strength did not differ between these groups (t₂₈ = 1.057; P < 0.300; ES = 0.17).

Interpretation

Greater hamstring stiffness, but not strength, results in a more stable knee joint evidenced by less anterior tibial translation. These findings suggest that the hamstrings’ ability to resist lengthening rather than their overall force production capacity may be an important contributor to anterior cruciate ligament injury risk. As muscle stiffness can be modified acutely and chronically, enhancing hamstring stiffness may be an important addition to anterior cruciate ligament injury prevention programs.     

超声联合PNF对骨折后伸直型膝关节僵硬的疗效观察

目的:探讨超声联合PNF综合康复疗法对骨折后伸直型膝关节僵硬的疗效。方法:将符合纳入标准的53例膝关节僵硬患者随机分为传统组和康复组,在常规药物及肌力训练基础上分别给予传统关节松动术和本体感觉神经肌肉促进技术(PNF)联合超声治疗。治疗前后观察关节活动度,视觉疼痛模拟评分和膝关节功能改善积分。结果:治疗2个月后在关节活动度和膝关节功能改善积分方面,康复组优于传统组(P0.05),视觉疼痛模拟评分2组差异无统计学意义。2组3种评定方法治疗前后组内比较,治疗后优于治疗前(P0.05)。结论:超声联合PNF模式功能训练的综合康复疗法对膝关节僵硬功能的改善优于传统关节松动术。     

Short-term effects of mobilisation with movement in patients with post-traumatic stiffness of the knee joint

Background

Mobilisation with movement treatment techniques have been used to increase the range of motion following pathologies associated with shoulder, elbow and ankle joints. Lack of posterior tibial glide and reflex muscle inhibition are common physical impairments in individuals with post-traumatic stiffness of the knee joint. Current evidence is lacking for the benefits of mobilisation with movement treatment techniques for the knee joint disorders.

The initial effects of knee joint mobilization on osteoarthritic hyperalgesia

Physiotherapists often employ lower limb joint mobilization to reduce pain and increase function. However, there is little experimental data confirming its efficacy. The purpose of this study was to investigate the initial effects of accessory knee joint mobilization on measures of pain and function in individuals with knee osteoarthritis. The study employed a double-blind, controlled, within-subjects repeated-measures design. Thirty-eight subjects with mild to moderate knee pain participated. The effects of a 9-min, non-noxious, AP mobilization of the tibio-femoral joint were compared with manual contact and no-contact interventions. Pressure pain threshold (PPT) and 3-m 'up and go' time were measured immediately before and after each intervention. Results demonstrated a significantly greater mean (95% CI) percentage increase in PPT following knee joint mobilization (27.3% (20.9-33.7)) than after manual contact (6.4% (0.4-12.4)) or no-contact (-9.6% (-20.7 to 1.6)) interventions. Knee joint mobilization also increased PPT at a distal, non-painful site and reduced 'up and go' time significantly more (-5% (-9.3 to 0.8)) than manual contact (-0.4% (-4.2 to 3.5)) or no-contact control (+7.9% (2.6-13.2)) interventions. This study therefore provides new experimental evidence that accessory mobilization of an osteoarthritic knee joint immediately produces both local and widespread hypoalgesic effects. It may therefore be an effective means of reducing pain in this population.     

Effect of gender, age, and anthropometry on axial and appendicular muscle strength

OBJECTIVE: To assess age and gender differences in muscle strength. DESIGN: The strength of back extensors, upper limbs (grip), and lower limbs (knee extensors) was measured. Anthropometric measurements and body mass index also were assessed. RESULTS: Group comparisons were made for each decade. Back extensor strength (BES) in subjects aged 20 to 89 yr ranged from 93 to 832 N in men and from 71 to 440 N in women. BES peaked in the fourth decade for men and in the fifth decade for women. When the two genders were compared, muscle strength in women was less than that in men at all ages. At different decades, women's BES ranged from 54% to 76% compared with that of men's BES. There was a 64% loss of BES in men from the peak in their fourth decade (556 N) to the lowest level in their ninth decade (201 N). Women experienced a 50.4% loss from the peak in their fifth decade (306 N) to the lowest level in their ninth decade (152 N). CONCLUSIONS: Men had a greater loss of BES than women with increasing age. In both genders, there was more loss of BES than appendicular muscle strength. Reduction in BES in women coincided with increased body mass index in older age. In women, there was a negative correlation between body weight and level of physical activity, whereas this finding was not evident in men. Background factors related to a higher incidence of back pain, falls, and fractures, especially in women, may be a reduction in muscle strength, along with increasing age and body mass index. This cross-sectional study showed that physiologic reduction of muscle strength, which began early in life, later stopped and that muscle strength even improved, despite the aging process. Therefore, initiating strengthening exercises at any age is encouraged to prevent the impact of several age-related musculoskeletal challenges.     

The influence of sole wedges on frontal plane knee kinetics, in isolation and in combination with representative rigid and semi-rigid ankle-foot-orthoses

BACKGROUND: In earlier stages of knee osteoarthritis orthotic treatments with knee orthoses or modified footwear are often considered. Although the load reducing effects of knee orthoses have been well established, wearing modified footwear would be more comfortable for the patient and less encumbering. The effect of modified footwear on the frontal load of the knee is controversial. This article describes the effect of medial or lateral shoe wedges alone or together with two different types of ankle-stabilizing orthoses. METHODS: The effect on frontal knee loading was measured during standing and walking with medially and laterally placed wedges under the sole of the shoe. The wedges were also combined with two types of orthotic devices - an Ankle-Foot-Orthosis that was rigid in the frontal plane but allowed unrestricted sagittal plane motion and an ankle support that was semi-rigid in the frontal plane. Joint loading of 10 healthy persons (mean (standard deviation): age 34 (9) years, height 178 (4)cm, mass 73 (9)kg) was investigated by means of a special measuring device that accurately determines static loads (Lasar Posture) and with instrumented gait analysis (Vicon/Kistler). FINDINGS: Using a lateral wedge under the sole of the shoe (without orthotic support) showed no significant reduction in the mean maximal knee moment in the frontal plane. Adding an Ankle-Foot-Orthosis that is rigid in the frontal plane resulted in significant reduction in the maximal frontal moment from 0.54 Nm/kg to 0.38Nm/kg (p0.01). Using a medial wedge, without and with Ankle-Foot-Orthosis, produced a significant increase in the maximal frontal moment to 0.59 Nm/kg (p0.05) or 0.67 Nm/kg (p0.01), respectively. INTERPRETATION: These results suggest that the application of a sole wedge significantly influences frontal knee loading when used in combination with an Ankle-Foot-Orthosis that is rigid in the frontal plane.     

The effect of graft stiffness on knee joint biomechanics after ACL reconstruction--a 3D computational simulation

OBJECTIVE: The objective was to determine the effect of varying graft stiffness and initial graft tension on knee kinematics and graft tension after anterior cruciate ligament reconstruction. DESIGN: A 3D computational knee model was used. BACKGROUND: Many factors influencing the biomechanical outcome of anterior cruciate ligament reconstruction have been investigated. However, there are no reports on the effect of variations in graft stiffness on knee behavior. METHODS: A 3D computational knee model was used to simulate anterior cruciate ligament reconstruction using three different grafts with stiffnesses similar to the anterior cruciate ligament (graft 1), a 10mm bone-patellar tendon-bone graft (graft 2), and a 14 mm bone-patellar tendon-bone graft (graft 3). The initial graft tension was set to 0 or 40 N with the knee at 30 degrees of flexion. A 134 N anterior tibial drawer load and a 400 N quadriceps load were applied to the knee, and kinematics and graft tension were calculated. RESULTS: When fixed with no initial tension, graft 1 was found to under-constrain the knee, while graft 2 slightly over-constrained the knee, and graft 3 over-constrained the knee when compared to the intact knee. When an initial graft tension of 40 N was used, all of the reconstructed knees were more constrained than when an initial tension of 0 N was used. CONCLUSIONS: This study suggests that graft stiffness has a direct impact on knee biomechanics after anterior cruciate ligament reconstruction. An optimal anterior cruciate ligament reconstruction can be achieved if the anterior cruciate ligament is replaced by a graft with similar structural stiffness. RELEVANCE: This study showed that if the graft material and fixation sites are selected such that the anterior cruciate ligament structural stiffness is retained, normal knee kinematics can be restored.     

The relationship between hallux dorsiflexion and ankle joint complex frontal plane kinematics: a preliminary study

BACKGROUND: It has been suggested that the function of the first metatarsophalangeal joint may be related to the motion of the ankle joint complex. OBJECTIVE: This study explored the relationship between ankle joint complex and first metatarsophalangeal joint motion during gait in a group of 14 who demonstrated clinically limited passive hallux dorsiflexion in quiet standing (cases), and 15 matched controls. METHOD: An electromagnetic tracking system was used to measure the ankle joint complex frontal plane motion and first metatarsophalangeal joint sagittal plane motion during gait, in both cases and controls. The case group was then evaluated further to investigate the effect of an orthosis on first metatarsophalangeal joint motion. FINDINGS: The correlation between maximum ankle joint complex eversion and maximum first metatarsophalangeal joint dorsiflexion during gait was r=0.471. Within the case group, maximum rearfoot eversion was reduced following the application of the orthoses, but there was no change in sagittal first metatarsophalangeal joint rotations. INTERPRETATION: The relationship between maximum ankle joint complex eversion and first metatarsophalangeal joint dorsiflexion kinematics found in this study was moderate, and decreasing maximum ankle joint complex eversion with an orthosis did not result in any increase in first metatarsophalangeal joint dorsiflexion during gait in patients with functional first metatarsophalangeal joint limitation. These results do not support the assumption that ankle joint complex eversion influences first metatarsophalangeal joint motion substantially.     

Full biomechanical mapping of the ovine knee joint to determine creep-recovery,stiffness and thickness variation

BackgroundClinical cartilage repair strategies can be tested using the sheep model as suggest by the European Medicines Agency. To characterize variation within the joint a full biomechanical mapping is necessary. The aim of this study is to establish a loading model, to map regional differences within the knee and determine reference areas for area specific replacement techniques.MethodsA porous indenter was selected to evaluate 22 defined test locations (femoral condyles, tibia plateau, patella, femoral groove) on ovine knees (n = 7). A high-dynamic force-controlled micro creep and creep-recovery indentation test system applied five loading (0.11 MPa) and unloading (5.6 kPa) cycles for 60 s each and recorded creep-recovery. Needle indentation was used to measure cartilage thickness and calculate total strain.FindingsSteady state behaviour was observed from the third cycle and further evaluated. Little variation of stiffness in N/mm was found within the patella (4.3SD0.5) and femoral groove (8.1SD0.7) compared to larger variations in the femur (7.9SD2.0) and tibia (7.5SD3.2). Creep indentation showed values of 14.5%(SD2.7%) for the patella and 17.4%(SD3%) for the femoral grove opposed to 13.4%(SD4.3%) for the femoral condyles and 21.8%(SD6.6%) for the tibia plateau. Similar trends were observed analysing creep-recovery. Values were normalized to cartilage thickness which ranged between 0.36 mm and 1.14 mm.InterpretationOur setup allows a reliable evaluation of zonal differences. Homogenous biomechanical behaviour is found within the patella and femoral groove whereas significant biomechanical variation within the femoral condyles and tibia plateau indicates the need for site-specific cartilage repair products.     

Gender and age effects on elbow joint stiffness in healthy subjects

OBJECTIVE: To investigate the effect of demographic factors on upper-limb pendulum tests in healthy subjects. DESIGN: Experimental. Upper-limb pendulum tests were performed on healthy subjects. Biomechanical parameters of the elbow joint were estimated. The body weight, forearm length, gender, and age of subjects were recorded. The relationships among the biomechanical parameters and demographic factors were investigated. SETTING: A referral medical center in Taiwan. PARTICIPANTS: Healthy subjects (N=192). INTERVENTION: Upper-limb pendulum test. MAIN OUTCOME MEASURES: Number of swings, relaxation indices calculated from the angle trajectories, and stiffness constants and damping coefficients estimated from the elbow model were used as the biomechanic parameters of elbow joints. RESULTS: Age had little effect on the biomechanic parameters. Both mean stiffness constant and damping coefficient were larger in men. However, when the influence of body weight was corrected, the biomechanic parameters were the same for both genders. Forearm length had similar but weaker effects on stiffness constant and damping coefficient. CONCLUSIONS: In healthy subjects, the mechanical properties of the elbow joints were similar in men and women of comparable body weights and did not deteriorate significantly until subjects reached the age of 70 years.     

关节镜辅助松解治疗膝关节僵硬116列临床分析

目的探讨总结关节镜辅助下松解治疗膝关节僵硬的临床疗效。方法对116例膝关节僵硬患者进行松解治疗,其中62例膝关节伸直位纤维性僵硬患者采用膝关节镜前内、前外标准入路,在关节镜直视下行滑膜与纤维粘连组织刨削与切除,充分松解挛缩的组织,术后在镇痛下早期行康复训练,按照Jedut评分标准评定膝关节功能;对54例膝关节黏连性僵硬的患者采用关节镜下彻底清除瘢痕、充分松解挛缩的组织,术后早期康复训练。结果 116例患者治疗效果满意,经过术后随访,治疗后膝关节活动度恢复到120°～135°,平均87°,无皮肤坏死、感染等异常情况发生。结论关节镜辅助下松解治疗膝关节僵硬具有手术操作相对简单、安全、疗效好、术后并发症少等优点,且疗效确切,值得推广。     

持续被动运动在预防截瘫患者膝关节僵硬和肌肉萎缩中的作用

目的 探讨持续被动运动(continuous passive motion,CPM)对预防截瘫患者膝关节僵硬和肌肉萎缩的疗效.方法 将70例截瘫患者分为CPM组38例和对照组32例,CPM组应用CPM锻炼方法,对照组应用传统的被动锻炼方法.观察干预前后两组患者膝关节被动屈曲活动范围和股四头肌萎缩的情况.结果 CPM组膝关节活动范围受影响的程度明显小于对照组(P＜0.05),CPM组患者股四头肌萎缩发生率较对照组低(P＜0.05).结论 应用CPM锻炼方法可改善截瘫患者膝关节僵硬,预防股四头肌萎缩.     

The effects of wheelchair-seating stiffness and energy absorption on occupant frontal impact kinematics and submarining risk using computer simulation

Many wheelchair users must travel in motor vehicles while seated in their wheelchairs. The safety features of seat assemblies are key to motor vehicle occupant crash protection. Seating system properties such as strength, stiffness, and energy absorbance have been shown to have significant influence on risk of submarining. This study investigated the effects of wheelchair seat stiffness and energy absorption properties on occupant risk of submarining during a frontal motor vehicle 20 g/30 mph impact using a validated computer crash simulation model. The results indicate that wheelchair-seating stiffness and energy absorption characteristics influence occupant kinematics associated with the risk of submarining. Softer seat surfaces and relatively high energy absorption/permanent deformation were found to produce pelvis excursion trajectories associated with increased submarining risk. Findings also suggest that the current American National Standards Institute/Rehabilitation Engineering and Assistive Technology Society of North America (ANSI/RESNA) WC-19 seating integrity may not adequately assess submarining risk.     

Waking cervical pain and stiffness, headache, scapular or arm pain: gender and age effects

A random population-based study using a structured telephone questionnaire was undertaken to determine the frequency, duration and prevalence of waking cervical spine pain and stiffness, headache, and aching between the scapulae or in the arm and their relationship to age and gender. Seventy-six per cent of households contacted completed the questionnaire, yielding a total of 812 questionnaires. Subjects most commonly reported waking with scapular or arm pain (27%) followed by headache (19%), cervical pain (18%) and cervical stiffness (17%). The majority of subjects reported that symptoms lasted for more than an hour on one or two occasions during the week. Subjects who reported the presence of one type of waking symptom were significantly more likely to report other waking symptoms. Females were significantly more likely to wake with a headache than males (OR 2.5, 95% CI 1.6 to 4.0), while all subjects aged over 60 years were significantly less likely to wake with a headache than subjects in other age groups (OR 0.6, 95% CI 0.4 to 1.0). Females exhibited a decline in waking cervical pain, stiffness and headache with increasing age. In contrast, males exhibited a peak prevalence of waking cervical pain, stiffness and headache in the 40 to 59 year age group. The prevalence of waking with aching between the scapulae or in the arm behaved differently from the other symptom groups in both genders.     

The effects of transcutaneous electrical nerve stimulation on joint position sense in patients with knee joint osteoarthritis

The Tampa Scale of Kinesiophobia (TSK) has been used for a decade and is a valuable tool in researching pain-related fear. A variety of different factor models exist, however, and there are inconsistencies as to which model to use. The purpose of the study was twofold: 1) to thoroughly review existing factor models and 2) to empirically evaluate the previously proposed factor models in a large sample with persistent musculoskeletal pain. Subjects included 578 of 711 (81%) consecutive patients (aged 18-65 years) with persistent musculoskeletal pain from three different orthopedic outpatient clinics. We reviewed all existing factor models and performed confirmatory factor analyses on the existing models. Our review identified 11 factor models of the TSK. The identified models were tested on a large Swedish sample. All models were rejected because of unacceptable goodness-of-fit statistics in that specific sample. This study supports the fact that TSK is a multidimensional construct. Rather than searching for new factor solutions, future research should be devoted to forming a consensus for the conceptual and operational definitions of the construct kinesiophobia and the application of the Tampa Scale for Kinesiophobia. Physiotherapists are encouraged to take part in building new theories.