vendex and Contracture

Contracture, or loss of range of motion (ROM) of a joint, is a common clinical problem in individuals with spinal cord injury (SCI). In order to measure the possible contribution of changes in muscle length to the loss of ankle ROM, the active force vs. angle curves for the tibialis anterior (TA) and gastrocnemiussoleus (GS) were measured in 20 participants, 10 with SCI, and 10 gender and age matched, neurologically intact (NI) individuals. Electrical stimuli were applied to the TA and GS motor nerves at incremented angles of the entire ROM of the ankle and the resulting ankle and knee torques were measured using a multi-axis load cell. The muscle forces of the TA and GS were calculated from the torque measurements using estimates of their respective moment arms and the resulting forces were plotted against joint angle. The force-angle relation for the GS at the ankle (GSA) was significantly shifted into plantar flexion in SCI subjects, compared to NI controls (t-test, p<0.001). Similar results were obtained based upon the GS knee (GSK) force-angle measurements (p<0.05). Conversely, no significant shift in the force-angle relation was found for the TA (p=0.138). Differences in the passive ROM were consistent with the force-angle changes. The ROM in the dorsiflexion direction was significantly smaller in SCI subjects compared to NI controls (p<0.05) while the plantar flexion ROM was not significantly different (p=0.114). Based upon these results, we concluded that muscle shortening is an important component of contracture in SCI.

Topics: Adult; Ankle Joint; Cervical Vertebrae; Computer Simulation; Contracture; Electric Stimulation; Female; Humans; Male; Middle Aged; Models, Biological; Muscle Contraction; Muscle, Skeletal; Range of Motion, Articular; Spinal Cord Injuries; Stress, Mechanical; Thoracic Vertebrae; Torque

An intelligent stretching device was developed to treat the spastic/contractured ankle of neurologically impaired patients. The device stretched the ankle safely throughout the range of motion (ROM) to extreme dorsiflexion and plantarflexion until a specified peak resistance torque was reached with the stretching velocity controlled based on the resistance torque. The ankle was held at the extreme position for a period of time to let stress relaxation occur before it was rotated back to the other extreme position. Stretching was slow at the joint extreme positions, making it possible to reach a larger ROM safely and it was fast in the middle ROM so the majority of the treatment was spent in stretching the problematic extreme ROM. Furthermore, the device evaluated treatment outcome quantitatively in multiple aspects, including active and passive ROM, joint stiffness and viscous damping and reflex excitability. The stretching resulted in considerable changes in joint passive ROM, stiffness, viscous damping and reflex gain. The intelligent control and yet simple design of the device suggest that with appropriate simplification, the device can be made portable and low cost, making it available to patients and therapists for frequent use in clinics/home and allowing more effective treatment and long-term improvement.

Topics: Adult; Ankle Joint; Artificial Intelligence; Contracture; Elasticity; Equipment Design; Feasibility Studies; Humans; Male; Middle Aged; Motion Therapy, Continuous Passive; Muscle Spasticity; Range of Motion, Articular; Reflex, Stretch; Rotation; Sensitivity and Specificity; Stroke; Torque; Treatment Outcome; Viscosity

To determine the effect of 4 weeks of 30 minutes of daily stretching on ankle mobility in patients with recent spinal cord injuries (SCIs).. Assessor-blinded randomized controlled trial.. Two spinal injury units in Sydney, Australia.. Consecutive sample of 14 recently injured patients with paraplegia and quadriplegia.. Treated ankles were stretched continuously into dorsiflexion with a torque of 7.5 N x m for 30 minutes each weekday for 4 weeks. Contralateral ankles received no stretches.. Passive torque-angle curves for both ankles were obtained at study commencement, then at weeks 2, 4, and 5 (ie, during, at the end of, and 1 week after the stretching program). Torque-angle measurements were obtained with the knee extended and flexed. Mean values for parameters (baseline angle, angle at 10 N x m, slope) describing the characteristics of the torque-angle curves were derived for each knee position. Changes from pretest to each subsequent test were calculated, as well as 95% confidence intervals (CIs) for differences in these changes between stretched and controlled ankles.. The stretching intervention did not significantly change any of the 3 parameters describing the torque-angle curves of the ankle in either knee position. At the beginning of the study, the mean (+/-SD) angles obtained with the application of a standardized torque with the knee extended for the control and stretch ankles were 105 degrees (+/- 10.4 degrees) and 106 degrees (+/- 9.8 degrees), respectively. After 4 weeks, these values were 106 degrees (+/- 10.6 degrees) and 107 degrees (+/- 10.6 degrees) (mean difference in change of angle = 0 degrees; 95% CI, -3.3 degrees to 3.3 degrees).. Thirty minutes of daily stretching for 4 weeks does not significantly change ankle mobility in recently injured patients with SCIs.

Topics: Adult; Ankle Joint; Biomechanical Phenomena; Contracture; Humans; Male; Paraplegia; Quadriplegia; Range of Motion, Articular; Rehabilitation; Spinal Cord Injuries; Statistics, Nonparametric; Torque

Deficits in plantarflexor kinetics are associated with poor outcomes in patients following Achilles tendon rupture. In this longitudinal study, we analyzed the fascicle length and pennation angle of the medial gastrocnemius muscle and the length of the Achilles tendon using ultrasound imaging. To determine the relationship between muscle remodeling and deficits in plantarflexor kinetics measured at 14 wk after injury, we correlated the reduction in fascicle length and increase in pennation angle with peak torque measured during isometric and isokinetic plantarflexor contractions. We found that the medial gastrocnemius underwent an immediate change in structure, characterized by decreased length and increased pennation of the muscle fascicles. This decrease in fascicle length was coupled with an increase in tendon length. These changes in muscle-tendon structure persisted throughout the first 14 wk following rupture. Deficits in peak plantarflexor torque were moderately correlated with decreased fascicle length at 120 degrees per second (

Topics: Achilles Tendon; Adult; Ankle; Ankle Joint; Contracture; Humans; Kinetics; Longitudinal Studies; Male; Movement; Muscle, Skeletal; Tendon Injuries; Torque; Ultrasonography

Joint contractures are a common complication of many neurologic conditions, and stretching often is advocated to prevent and treat these contractures. However, the magnitude and duration of the stretching done in practice usually are guided by subjective clinical impressions.. Using an established T8 spinal cord injury rat model of knee contracture, we sought to determine what combination of static or intermittent stretching, varied by magnitude (high or low) and duration (long or short), leads to the best (1) improvement in the limitation in ROM; (2) restoration of the muscular and articular factors leading to contractures; and (3) prevention and treatment of contracture-associated histologic alterations of joint capsule and articular cartilage.. Using a rat animal model, the spinal cord was transected completely at the level of T8. The rats were randomly assigned to seven treatment groups (n = 4 per group), which were composed of static or intermittent stretching in combination with different amounts of applied torque magnitude and duration. We assessed the effect of stretching by measuring the ROM and evaluating the histologic alteration of the capsule and cartilage.. Contractures improved in all treated groups except for the low-torque and short-duration static stretching conditions. High-torque stretching was effective against shortening of the synovial membrane and adhesions in the posterosuperior regions. Collagen Type II and VEGF in the cartilage were increased by stretching.. High-torque and long-duration static stretching led to greater restoration of ROM than the other torque and duration treatment groups. Stretching was more effective in improving articular components of contractures compared with the muscular components. Stretching in this rat model prevented shortening and adhesion of the joint capsule, and affected biochemical composition, but did not change morphologic features of the cartilage.. This animal study tends to support the ideas that static stretching can influence joint ROM and histologic qualities of joint tissues, and that the way stretching is performed influences its efficacy. However, further studies are warranted to determine if our findings are clinically applicable.

Topics: Animals; Biomechanical Phenomena; Cartilage, Articular; Collagen Type II; Contracture; Disease Models, Animal; Joint Capsule; Knee Joint; Male; Muscle Stretching Exercises; Range of Motion, Articular; Rats; Rats, Wistar; Spinal Cord Injuries; Time Factors; Torque; Vascular Endothelial Growth Factor A

Prospective cohort study.. To determine incidence of contracture and develop prediction models to identify patients susceptible to contracture after spinal cord injury.. Two Sydney spinal cord injury units.. A total of 92 consecutive patients with acute spinal cord injury were assessed within 35 days of injury and 1 year later. Incidence of contracture at 1 year was measured in all major appendicular joints by categorizing range of motion on a 4-point scale (0-no contracture to 3-severe contracture), and in the wrist, elbow, hip and ankle by measuring range of motion at standardized torque. Multivariate models were developed to predict contracture at 1 year using age, neurological status, spasticity, pain and limb fracture recorded at the time of injury.. At 1 year, 66% of participants developed at least one contracture (defined as ≥1 point deterioration on the 4-point scale). Incidence of contracture at each joint was: shoulder 43%, elbow and forearm 33%, wrist and hand 41%, hip 32%, knee 11% and ankle 40%. Incidence of contracture determined by standardized torque measures of range (defined as loss of ≥10 degrees) was: elbow 27%, wrist 26%, hip 23% and ankle 25%. Prediction models were statistically significant but lacked sufficient predictive accuracy to be clinically useful (R(2)≤31%).. The incidence of contracture in major joints 1 year after spinal cord injury ranges from 11-43%. The ankle, wrist and shoulder are most commonly affected. It is difficult to accurately predict those susceptible to contracture soon after injury.

Topics: Adult; Cohort Studies; Contracture; Humans; Incidence; Joints; Middle Aged; Muscle Spasticity; Predictive Value of Tests; Prospective Studies; Range of Motion, Articular; Severity of Illness Index; Spinal Cord Injuries; Torque

To investigate the mechanisms of contracture after stroke by comparing passive mechanical properties of gastrocnemius muscle-tendon units, muscle fascicles, and tendons in people with ankle contracture after stroke with control participants.. Cross-sectional study.. Laboratory in a research institution.. A convenience sample of people with ankle contracture after stroke (n=20) and able-bodied control subjects (n=30).. Not applicable.. Stiffness and lengths of gastrocnemius muscle-tendon units, lengths of muscle fascicles, and tendons at specific tensions.. At a tension of 100N, the gastrocnemius muscle-tendon unit was significantly shorter in participants with stroke (mean, 436mm) than in able-bodied control participants (mean, 444mm; difference, 8mm; 95% confidence interval [CI], 0.2-15mm; P=.04). Muscle fascicles were also shorter in the stroke group (mean, 44mm) than in the control group (mean, 50mm; difference, 6mm; 95% CI, 1-12mm; P=.03). There were no significant differences between groups in the mean stiffness or length of the muscle-tendon units and fascicles at low tension, or in the mean length of the tendons at any tension.. People with ankle contracture after stroke have shorter gastrocnemius muscle-tendon units and muscle fascicles than control participants at high tension. This difference is not apparent at low tension.

Topics: Aged; Aged, 80 and over; Ankle Joint; Biomechanical Phenomena; Contracture; Cross-Sectional Studies; Female; Follow-Up Studies; Humans; Likelihood Functions; Linear Models; Male; Middle Aged; Muscle Contraction; Muscle Fibers, Skeletal; Muscle, Skeletal; Reference Values; Severity of Illness Index; Stress, Mechanical; Stroke; Stroke Rehabilitation; Torque; Ultrasonography, Doppler

Efficacy of knee flexion contracture treatment protocols is dependent on the torque applied to the joint, but to date, no published reports have evaluated the torque applied by the available treatment options. The purpose of this study was to measure the torque applied by physical therapists (PTs), home exercises, and mechanical therapy devices. An instrumented test leg recorded peak torque applied by 14 PTs performing knee extension mobilization, 2 home exercises, and 3 types of mechanical therapy (dynamic splint, static progressive stretch, and patient-actuated serial stretch). Physical therapists applied 68.0 N m, patient-actuated serial stretch mechanical therapy applied 53.0 N m, and the other therapies ranged between 4.6 and 12.4 N m. The reported torque values can be used to help improve the efficacy of flexion contracture treatment protocols.

Topics: Adult; Contracture; Female; Humans; Knee Joint; Male; Physical Therapy Modalities; Torque

Prolonged immobilization reduces passive range of motion of joints creating joint contractures. Whether and to what extent these iatrogenic contractures can be reduced is unknown. We raised three questions using an animal model: What degree of contracture remains at the end of a defined remobilization period? Do contractures in sham-operated and immobilized joints differ? What is the contribution of the posterior knee capsule in limiting knee extension? We immobilized one knee of 11 adult male rats in flexion to induce a joint contracture; 10 control animals underwent a sham operation. After 8 weeks, the internal fixation device was removed, and the animals were allowed to resume unrestricted activity for 4 weeks at the end of which the knee range of motion was measured with standardized torques. The mean flexion contracture was higher in the immobilized group (51.9 degrees +/- 2.8 degrees ) than in the sham-operated group (18.9 degrees +/- 2.1 degrees ). Eighty-eight percent of the contractures remained in the immobilized group after dividing skin and muscle, suggesting an important contribution of the posterior knee capsule in limiting knee mobility. Based on our preliminary study the range of motion of rat knees immobilized for 8 weeks remained substantially reduced after a 4-week period of unassisted remobilization.

Topics: Animals; Contracture; Disease Models, Animal; Immobilization; Joint Capsule; Knee Joint; Male; Pilot Projects; Range of Motion, Articular; Rats; Rats, Sprague-Dawley; Recovery of Function; Time Factors; Torque

Tension is necessary to maintain and restore the mechanical properties of soft connective tissues. Conversely, reduced tension states such as produced by immobilization weaken mechanical properties and facilitate joint contracture. We assessed the effect of low torque-long duration stretching to increase the range of motion (ROM) and to restore the mechanical properties of contracted joints in 66 rat knees immobilized for 40 days. After remobilization, we randomly divided the contracted knees into four treatment groups treated with repeated stretches of diverse torques and duration: stretching with low-torque and long-duration, high-torque and short-duration, high-torque and long-duration, low-torque and short duration. We included control and natural recovery groups. Phase lag in all treatment groups recovered to the same range as in the normal controls. Dynamic stiffness, which was not altered by joint immobilization, increased in all treatment groups. Deformation and load to failure improved substantially only in the low-torque and long-duration stretching group. Low-torque and long-duration repeated stretching leads to a greater restoration of ROM with more normal mechanical properties compared to high-torque and short duration stretching.

Topics: Animals; Contracture; Male; Physical Therapy Modalities; Range of Motion, Articular; Rats; Rats, Wistar; Time Factors; Torque

The purpose of this study was to clarify the relationship between mechanical stress and tissue response of the contracted knee joint in rats and to propose a new design of contracture correction device for clinical use. Wistar rats were operated on to immobilize their knee joints with a procedure causing periarticular bleeding and were kept in flexed position for 40 days. At day 40, the immobilizing wire was removed, and after day 43, the contracted knee joint had been treated with tunable corrective devices secured by an external fixation method to the rear limb. These devices consisted of four types of motor-driving system which provided several different low-load and continuous stretch torques. Measuring the angle of maximum knee extension, its effectiveness was assessed comparing with a lower load and control group of natural recovery course. The device also had a cyclic joint movement within the acquired range of motion and an oval cam mechanism producing a small distraction force to the joint along its long axis. The results showed that an appropriate range of low-load continuous torque was more effective to correct joint contracture. On the basis of the animal experiment, a new computer-controlled, gas-driven contracture correction device was developed for clinical trial. It was concluded that mechanical application in a condition with low and continuous torque is a useful treatment for fixed joint contracture.

Topics: Animals; Contracture; Disease Models, Animal; Equipment Design; Knee Joint; Male; Range of Motion, Articular; Rats; Rats, Wistar; Therapy, Computer-Assisted; Torque; Weight-Bearing

Topics: Animal Welfare; Animals; Contracture; Disease Models, Animal; Rats; Therapy, Computer-Assisted; Torque

To establish (1) whether associated reactions could contribute to contracture formation and (2) whether the presence of spasticity was essential for their expression, after stroke.. Subjects were 24 hemiparetics within 13 months of a stroke, unselected for contracture or spasticity.. Associated reactions were identified by the presence of muscle activity in the affected biceps brachii and quantified as the amount of affected elbow flexor torque produced during a moderate contraction of either the contralateral biceps brachii or the contralateral quadriceps muscles. Contracture was measured as loss of elbow joint range of motion and spasticity as the presence of abnormal reflex activity.. Associated reactions were present in at least one testing condition in seven subjects. During contractions of the contralateral biceps brachii, the median amount of elbow flexor torque produced was 0.39 (interquartile range, IQR 2.5) Nm while during contractions of the contralateral quadriceps muscle it was 0.19 (IQR 1.6) Nm. Associated reactions were not associated with contracture (p = 0.39) which was present in over half of the subjects. The incidence of associated reactions was about the same as that of spasticity, but the two were not related (p = 0.61).. Even though associated reactions were present in 29% of the subjects during moderate contraction of the contralateral muscles, they were not large, nor were they associated with contracture or spasticity, suggesting that this phenomenon is not usually a major problem for everyday function after stroke.

Topics: Adult; Aged; Aged, 80 and over; Arm; Contracture; Disabled Persons; Electromyography; Female; Humans; Incidence; Male; Middle Aged; Muscle Contraction; Muscle Spasticity; Paresis; Range of Motion, Articular; Reflex, Abnormal; Severity of Illness Index; Stroke; Tomography, X-Ray Computed; Torque

To measure articular structures' contribution to the limitation of range of motion after joint immobility.. Experimental, controlled study involving 40 adult rats that had one knee joint immobilized in flexion for durations of 2, 4, 8, 16, and 32 weeks; 20 rats underwent a sham procedure. The angular displacement was measured both in flexion and extension at three different torques. Myotomy of transarticular muscles allowed isolation of the arthrogenic component of the contracture.. A contracture developed in all immobilized knees. The articular structures were incrementally responsible for the limitation in range of motion (from 12.6 degrees +/-6.7 degrees at 2 weeks to 51.4 degrees +/-5.4 degrees at 32 weeks). The myogenic restriction proportionately decreased over time (from 20.1 degrees +/-8.4 degrees at 2 weeks to only 0.8 degrees +/-7.2 degrees at 32 weeks). The increase in the arthrogenic component of contracture was predominant in extension.. This study quantified the increasing role of arthrogenic changes in limiting the range of motion of joints after immobility, especially as the period of immobility extended past 2 weeks. These data provide a better understanding of joint contracture development and can be used to guide therapeutic approaches.

Topics: Animals; Contracture; Immobilization; Knee Joint; Male; Range of Motion, Articular; Rats; Rats, Sprague-Dawley; Torque

Animal models for joint diseases are necessary for in vivo studies. Joint contractures are characterized by lack of the normal range of motion of a joint most often due to increased soft tissue stiffness. Biological and biochemical data have been obtained but biomechanical data on small animals are rare. An instrument was developed to measure rat knee angular displacement at various soft tissue loads in normal and pathological circumstances. This article describes the instrument and reports its reproducibility and accuracy. The reproducibility and accuracy of this instrument was found to be acceptable thereby validating its use for research purposes with adult rat knees.

Topics: Animals; Anthropometry; Bias; Contracture; Disease Models, Animal; Equipment Design; Knee Joint; Range of Motion, Articular; Rats; Reproducibility of Results; Torque; Weight-Bearing