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PubMed2005

Relationship of spasticity to knee angular velocity and motion during gait in cerebral palsy.

This study investigated the effects of spasticity in the hamstrings and quadriceps muscles on gait parameters including temporal spatial measures, knee position, excursion and angular velocity in 25 children with spastic diplegic cerebral palsy (CP) as compared to 17 age-matched peers. While subjects were instructed to relax, an isokinetic device alternately flexed and extended the left knee at one of the three constant velocities 30 degrees/s, 60 degrees/s and 120 degrees/s, while surface electromyography (EMG) electrodes over the biceps femoris and the rectus femoris recorded muscle activity. Patients then participated in 3D gait analysis at a self-selected speed. Results showed that, those with CP who exhibited heightened stretch responses (spasticity) in both muscles, had significantly slower knee angular velocities during the swing phase of gait as compared to those with and without CP who did not exhibit stretch responses at the joint and the tested speeds. The measured amount (torque) of the resistance to passive flexion or extension was not related to gait parameters in subjects with CP; however, the rate of change in resistance torque per unit angle change (stiffness) at the fastest test speed of 120 degrees/s showed weak to moderate relationships with knee angular velocity and motion during gait. For the subset of seven patients with CP who subsequently underwent a selective dorsal rhizotomy, knee angular extension and flexion velocity increased post-operatively, suggesting some degree of causality between spasticity and movement speed.

Biomechanical Phenomena↗

PubMed2003

A wheelchair modified for leg propulsion using voluntary activity or electrical stimulation.

A commercially available wheelchair has been modified for propulsion by movements of the lower legs. The feet are attached securely to a foot rest that can rotate around the knee joint. Movement is generated either with residual voluntary activation of the quadriceps (knee extensor) and hamstring (knee flexor) muscles, or with electrical stimulation of these muscles, if voluntary control is absent. Either a chain or a lever can couple the movements through a gearbox to the wheel to propel the wheelchair forward. Control of a wheelchair with the legs is more efficient than using the arms and has the potential to increase the mobility and whole-body fitness of many wheelchair users, but there is considerable variability between subjects. To address this variability, we measured for individual subjects the passive properties of the legs and foot at rest (effective stiffness and viscosity), the length-tension (torque-angle) properties of the active muscle groups, as well as their force-velocity curve and their activation and fatigue rates. The measured values were then inserted into a model of the leg-propelled wheelchair. The purpose of this paper is to test whether the model could predict the performance of individual subjects accurately and could be used, for example, to optimize the speed of the wheelchair for a given subject.

Computer-Aided Design↗

PubMed1995

Effects of electrically-stimulated exercise and passive motion on echocardiographically-derived wall motion and cardiodynamic function in tetraplegic persons.

The purposes of the study were (1) to characterize left ventricular wall motion, and the cardiodynamic and metabolic responses during electrical stimulation cycle ergometry (ESCE) exercise in tetraplegic people; (2) to test whether these responses linger into the post-exercise recovery period; and (3) to test whether they differ from those imposed by lower extremity continuous passive motion (CPM). Subjects were six tetraplegic males aged 25.8 +/- 3.1 (mean +/- SD) years with spinal cord injuries of 6.7 +/- 3.5 years' duration at the C5 and C6 levels (Frankel classifications A and B). On randomized non-consecutive days, subjects underwent either 30 min of steady-state exercise using transcutaneous electrically-stimulated contractions of bilateral quadriceps, hamstring, and gluteus muscle groups, or 30 min of continuous passive motion at 50 rpm. Data were taken at rest, min 15 and 30 of treatment, and min 5, 15, and 30 post-treatment. Stroke volume (SV) was measured echocardiographically as the product of the left ventricular outflow tract area and the integrated area under the left ventricular outflow tract flow-velocity curve acquired by doppler ultrasound. This value was multiplied by heart rate (HR) to determine the cardiac output (CO). Oxygen consumption (VO2) was monitored spirometrically, with arteriovenous oxygen difference (a-vO2DIFF) computed algebraically. Data were analyzed using repeated measures within-subjects design anaysis of variance, with significance accepted at the 0.05 level. Results showed five subjects had small hyperkinetic ventricles at rest that became more dynamic during ESCE than CPM. Though no systolic dysfunction was noted, all but one subject exhibited some degree of septal hypokinesis at rest and during exercise, possibly indicative of left ventricular noncompliance. Significant effects of condition (ESCE vs CPM), trial (measurement time point), and their interaction, were observed for CO (P < 0.05, 0.01, and 0.0001, respectively), HR (P < 0.0001, 0.05 and 0.005, respectively), and VO2 (P < 0.001, 0.05 and 0.005, respectively). A significant trial and condition by trial interaction was found for a-vO2DIFF (P < 0.05 and 0.0001, respectively). No effects for condition, trial or their interaction were found for SV or BPDIAS. Electrical stimulation cycle ergometry-treated subjects achieved peak VO2 of 712 +/- 300 ml min-1, 2.63 times baseline, with 56% elevation of a-vO2DIFF. Cardiac output increased from 3.5 +/- 1.51 min-1 to 6.0 +/- 2.11 min-1, an elevation solely attributable to a 57% increase in HR. Thus, both CO and a-vO2DIFF accounted for elevated VO2 during ESCE.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1997

Long-term adaptation to electrically induced cycle training in severe spinal cord injured individuals.

Spinal cord injured (SCI) individuals most often contract their injury at a young age and are deemed to a life of more or less physical inactivity. In addition to the primary implications of the SCI, severe SCI individuals are stigmatized by conditions related to their physically inactive lifestyle. It is unknown if these inactivity related conditions are potentially reversible and the aim of the present study was, therefore, to examine the effect of exercise on SCI individuals. Ten such individuals (six with tetraplegia and four with paraplegia; age 27-45 years; time since injury 3-23 years) were exercise trained for 1 year using an electrically induced computerized feedback controlled cycle ergometer. They trained for up to three times a week (mean 2.3 times), 30 min on each occasion. The gluteal, hamstring and quadriceps muscles were stimulated via electrodes placed on the skin over their motor points. During the first training bouts, a substantial variation in performance was seen between the subjects. A majority of them were capable of performing 30 min of exercise in the first bout; however, two individuals were only able to perform a few minutes of exercise. After training for 1 year all of the subjects were able to perform 30 min of continuous training and the work output had increased from 4 +/- 1 (mean +/- SE) to 17 +/- 2 Kilo Joules per training bout (P < 0.05). The maximal oxygen uptake during electrically induced exercise increased from 1.20 +/- 0.08 litres per minute measured after a few weeks habituation to the exercise to 1.43 +/- 0.09 litres per minute after training for 1 year (P < 0.05). Magnetic resonance cross sectional images of the thigh were performed to estimate muscle mass and an increase of 12% (mean, P < 0.05) was seen in response to 1 year of training. In biopsies taken before exercise various degrees of atrophy were observed in the individual muscle fibres, a phenomenon that was partially normalized in all subjects after training. The fibre type distribution in skeletal muscles is known to shift towards type IIB fibres (fast twitch, fast fatiguable, glycolytic fibres) within the first 2 years after the spinal cord injury. The muscle in the present investigation contained of 63% myosin heavy chain (MHC) isoform IIB, 33% MHC isoform IIA (fast twitch, fatigue resistant) and less than 5% MHC isoform I (slow twitch) before training. A shift towards more fatigue resistant contractile proteins was found after 1 year of training. The percentage of MHC isoform IIA increased to 61% of all contractile protein and a corresponding decrease to 32% was seen in the fast fatiguable MHC isoform IIB, whereas MHC isoform I only comprised 7% of the total amount of MHC. This shift was accompanied by a doubling of the enzymatic activity of citrate synthase, as an indicator of mitochondrial oxidative capacity. It is concluded that inactivity-associated changes in exercise performance capacity and skeletal muscle occurring in SCI individuals after injury are reversible, even up to over 20 years after the injury. It follows that electrically induced exercise training of the paralysed limbs is an effective rehabilitation tool that should be offered to SCI individuals in the future.

Adaptation, Physiological↗

PubMed2001

Spasticity versus strength in cerebral palsy: relationships among involuntary resistance, voluntary torque, and motor function.

Despite the lack of consensus of the role of spasticity in the observed motor disability in cerebral palsy (CP), alleviation of spasticity remains a primary focus in the clinical management of these patients. The purposes of this study were to: (1) quantify voluntary torque and passive resistance across speeds in the hamstrings and quadriceps muscle groups with respect to the presence of stretch responses and/or passive muscle stiffness in patients with CP compared to age-related children without disability, and (2) relate these parameters to each other and to functional performance, as measured by the Gross Motor Function Measure (GMFM), in CP. Included were 23 subjects with CP, sub-grouped by the presence or absence of stretch responses as determined by electromyography, and 9 subjects without CP. Results indicated that peak torque was considerably greater in the comparison group than for each of the CP groups and resistance was greater in the CP group with spasticity compared to the nonspastic CP group in both muscles at all speeds. Stiffness differed between the spastic CP group and the comparison group only for the quadriceps at the fastest speed. Higher passive resistance torque and stiffness were correlated with decreased voluntary torque, particularly for the antagonists, and with lower GMFM scores. In conclusion, strength and motor function are related to the magnitude of resistance torque and stiffness in CP, although the small amount of variance explained reinforces the multidimensional nature of this disorder, and the challenges inherent in managing it.

Analysis of Variance↗

PubMedDate not supplied

Effects of functional electrical stimulation-induced lower extremity cycling on bone density of spinal cord-injured patients.

Spinal cord-injured (SCI) patients are at increased risk for fractures secondary to neurogenic osteoporosis. Earlier research claimed physical conditioning resulted in a decreased incidence or reversal of neurogenic osteoporosis. This study evaluated the effects of functional electrical stimulation-induced lower extremity cycling (FESILEC) on the bone densities of SCI patients using dual-energy x/ray absorptiometry (DEXA). The study consisted of 12 healthy male SCI patients, aged 23 to 46 (x +/- SD, 34 +/- 6) yr. The patients were post-traumatic, complete, spastic SCI; time postinjury ranged from 2 to 19 (9.7 +/- 5.1) yr. Patients participated in a three-phase training program. Phase 1 consisted of quadriceps strengthening. Phase 2 consisted of progressive sequential stimulation of quadriceps, hamstrings, and gluteal muscles, achieving a rhythmical pedaling motion on the REGYS I ergometer. Phase 3a consisted of 30-min FESILEC sessions. DEXAs were done at baseline and at completion of Phase 3a and Phase 3b. Bone densities were done of the lumbar spine levels 2-4 (L2-4), bilateral trochanters (T), Ward's triangles (WT) and femoral necks (FN). Baseline bone density indicated no difference between L2-4 of ambulatory males and SCI males. Baseline values obtained for T, WT, and FN were, respectively, 71, 82, and 79% of ambulatory values. Results after completion of the Phase 3a training program indicated no statistically significant difference compared with baseline values. There was, however, a positive trend in the lumbar spine post-Phase 3a (L2-4, P=0.056). Eight patients continued the exercise program, using a combination of upper and lower extremity cycling (Phase 3b) for a longer period of time (25 +/- 9 wk). DEXAs done after Phase 3b indicated no change relative to baseline data or data post-Phase 3a. In conclusion, although FESILEC did not significantly increase bone density in the hip parameters of chronic SCI patients, a positive trend was observed in the lumbar spine. Further research with acute intervention, such as FESILEC during the first few months post-SCI, is warranted to further evaluate a treatment regimen to prevent or reduce neurogenic osteopenia.

Absorptiometry, Photon↗

PubMedDate not supplied

Comparison of balance responses and motor patterns during sit-to-stand task with functional mobility in stroke patients.

This study was undertaken to explore whether we could provide supportive laboratory evidence for the clinical observations that a stroke patient has lost functional mobility/locomotion capability based on dynamic balance responses (center of force sway patterns) and motor control activities (electromyography patterns) during the motor task of sit-to-stand. A computerized controlled dynamic postural control assessment system was developed and used in this study. Various dynamic balance indexes were introduced and derived from center of force sway patterns expressed in four domains (space, time, force, and frequency). Motor control was assessed by multichannel surface electromyography of each side of the lower limb during the same motor task. The functional mobility capability was evaluated using the traditional FIM method. Fourteen stroke patients with right hemiplegia and nine healthy elderly individuals were recruited as the experimental and control groups, respectively. Muscle activity was recorded for quadriceps, hamstrings, anterior tibialis, and triceps surae muscles and was used for analysis. Center of force sway patterns and ground reaction forces were registered. All signals were synchronized at "seat-off." Surface electromyographic patterns of activities recorded during sit-to-stand and dynamic balance indexes computed from center of force sway patterns were categorized and compared with the functional mobility scores. Results show that both the motor control patterns and dynamic balance indexes correlated well to the extent of mobility impairment evaluated using the traditional FIM method. An important conclusion for rehabilitation medicine is that the functional mobility capability of stroke patients may be expressed numerically using dynamic balance indexes and visualized graphically through electromyographic motor patterns.

Adult↗

PubMed1996

Subject-related risk factors for sports injuries: a 1-yr prospective study in young adults.

The purpose of this study was to investigate the importance of subject-related risk factors for sports injuries, taking exposure time into account. At baseline in 182 healthy males and females (27 yr) the following subject-related risk factors were assessed: body mass index (BMI), maximal oxygen uptake (direct treadmill measurement), seven aspects of neuromotor fitness (MOPER fitness test), strength of the hamstring and quadriceps muscles (CYBEX), having sustained a sports injury in the 12 months preceding the baseline measurement ("previous injury"), and 16 psychological and psychosocial factors (measured with 8 standard, valid, and reliable questionnaires). For 1 yr, subjects were asked to make daily entries on a monthly log concerning all sports activities exceeding an intensity of 4 MET and all sustained sport injuries. Completed logs were returned by 139 subjects (75 males and 64 females). Fifty-one injuries were registered in 41 subjects. The overall incidence rate (IR) was 3.7 sports injuries per 1000 h of sports participation (95% confidence interval 2.8-4.9). For various subcategories, the following IR per 1000 h of sports participation were calculated: contact sports IR = 11.0 (95% CI 7.4-16.3); noncontact sports IR = 2.3% (95% CI 1.6-3.3); competition IR = 13.4 (95% CI 8.7-20.6); and training IR = 2.8 (95% CI 1.6-5.1). Data were analyzed by stepwise multiple logistic regression. The following five variables were independent and significant (P < 0.05) predictors of risk in sustaining a sport injury: dominance (odds ratio (OR) = 1.71; 95% CI = 1.44-2.03), vital exhaustion (OR = 1.85; CI = 1.22-2.86), stressful life events (OR = 1.84; 95% CI = 1.10-311); these ORs were calculated for an increase of 10% of the range of obtained scores, starting at minimum value. For total sporting time, the OR was calculated by taking the group with a total sporting time below the median (4050 h) as a reference (OR = 6.87; 95% CI = 2.09-22.55). For previous injury, subjects that had not sustained a sports injury in the 12 months preceding the baseline measurements served as a reference for the calculation of the OR (OR = 9.41; 95% CI = 2.80-31.58). These findings confirm that both exposure time and previous injury are more important predictors of sports injuries than psychological, psychosocial, physiological, and anthropometrical factors.

Adult↗

PubMed2001

Risk factors for training-related injuries among men and women in basic combat training.

PURPOSE: Past investigations indicate that training-related injuries are associated with certain performance-oriented measures of physical fitness and certain lifestyle characteristics. This study examined associations between injuries, direct (physiological) measures of physical fitness, and lifestyle characteristics. METHODS: Subjects were 756 men and 474 women performing the standardized activities involved in U.S. Army Basic Combat Training (BCT). Before BCT, a subsample of subjects (182 men and 168 women) were administered a series of tests that included a treadmill running test (peak VO2), dual-energy x-ray absorptiometry (for body composition), several measures of muscle strength, a hamstring flexibility test, and a vertical jump. A questionnaire addressed smoking habits and prior physical activity. All subjects were administered the Army Physical Fitness test consisting of push-ups, sit-ups, and a 3.2-km run. Gender, age, stature, and body mass were obtained from physical examination records. Injuries incurred during BCT were transcribed from medical records; for each medical visit, the diagnosis, anatomical location, disposition (final outcome of visit), and days of limited duty were recorded. RESULTS: Women had over twice the injury rate of men. For men and women, fewer push-ups, slower 3.2-km run times, lower peak VO2, and cigarette smoking were risk factors for time-loss injury. Among the men only, lower levels of physical activity before BCT and both high and low levels of flexibility were also time-loss injury risk factors. Multivariate analysis revealed that lower peak VO2 and cigarette smoking were independent risk factors for time-loss injury. CONCLUSIONS: Lower aerobic capacity and cigarette smoking were independently associated with a higher likelihood of injury in both men and women during a standardized program of physical training. Further studies are needed to assess associations between injury and body composition and muscular strength.

Adolescent↗

PubMed2006

Physiotherapy assessment and treatment for an ambulant child with cerebral palsy after botox A to the lower limbs: a case report.

BACKGROUND AND PURPOSE: Botulinum toxin A is a relatively new, noninvasive treatment option for children with cerebral palsy, providing an effective, short-term intervention to reduce spasticity. It is used as an adjunct to other management including physiotherapy. The purpose of this case report is to evaluate assessment and management by physiotherapy following Botox injections to hamstring and gastrocnemius muscles. CASE DESCRIPTION: Examination of function and impairment for a 3.5-year-old child with spastic diplegia included the Gross Motor Function Measure, Goal Attainment Scaling, the Physician Rating Scale of gait, dynamic and passive range of movement, and selective motor control. Physiotherapy intervention was play based and occurred at home, at a preschool, and in the therapist's usual clinic setting, twice a week for the first five weeks, then once a week for another five weeks. Intervention consisted of whole and part practice of functional skills using closed and open chain exercises through the full available muscle range. OUTCOMES: The child showed increased ability in function; however, impairment level results were inconsistent and may not be effective at discerning change in a clinical setting. DISCUSSION: An increased level of physiotherapy was easily implemented by frequent and clear communication with those directly involved with the child's everyday activities. This is believed to have contributed to the successful outcomes seen.

Botulinum Toxins, Type A↗

PubMed1983

Radiating leg pain and positive straight leg raising in spondylolysis in children.

Three children presented with low back pain radiating to the leg and with spasm of the hamstring and paravertebral muscles. Since the pain could not be ascribed to trauma, it was necessary to exclude the presence of infection or tumors. All the signs--localization of the pain, tenderness on one side of the back, X-ray film findings of unilateral or bilateral spondylolysis, and localized positive bone scan--pointed to spondylolysis as the cause of pain. All three children exhibited symptoms resembling those found in the facet syndrome described by Mooney and Robertson.

Adolescent↗

PubMed1995

A new load application system for in vitro study of ligamentous injuries to the human knee joint.

This paper describes the design and accuracy evaluation of a new six degree of freedom load application system for in vitro testing of the human knee joint. External loads of both polarity in all six degrees of freedom can be applied either individually or in any combination while the knee is permitted to move unconstrained in response to applied loads. The flexion/extension degree of freedom permits the full physiological range of motion. In addition to external loads, forces of the three major muscle groups (quadriceps, hamstrings, gastrocnemius) crossing the joint can be developed. Full automation and rapid convergence of loads to programmed values are achieved through a computer which feeds command signals to servo controller/electro-pneumatic servo values. The servo values regulate pressure to pneumatic actuators which develop the various loads. Experiments undertaken to quantify the accuracy of both load and displacement measurements reveal that errors particularly in load measurement are effectively controlled through the apparatus design.

Anterior Cruciate Ligament↗

PubMed1993

Three-body segment dynamic model of the human knee.

In this paper, a two-dimensional, three-body segment dynamic model of the human knee is introduced. The model includes tibio-femoral and patello-femoral articulations, and anterior cruciate, posterior cruciate, medial collateral, lateral collateral, and patellar ligaments. It enables one to obtain dynamic response of the knee joint to any one or combination of quadriceps femoris, hamstrings, and gastrocnemius muscle actions, as well as any externally applied forces on the lower leg. A specially developed human knee animation program is utilized in order to fine tune some model parameters. Numerical results are presented for knee extension under the impulsive action of the quadriceps femoris muscle group to simulate a vigorous lower limb activity such as kicking. The model shows that the patella can be subjected to very large transient patello-femoral contact force during a strenuous lower limb activity even under conditions of small knee-flexion angles. The results are discussed and compared with limited data reported in the literature.

Biomechanical Phenomena↗

PubMed1995

EMG analysis of harmaline-induced tremor in normal and three strains of mutant mice with Purkinje cell degeneration and the role of the inferior olive.

1. The effects of intraperitoneal injections of 10 mg/kg harmaline were tested in normal mice and three strains of cerebellar mutant mice with Purkinje cell degeneration. Ten normal (wild-type) mice (+/+), as well as five lurcher (lc/+), six nervous (nr/nr), and eight Purkinje cell degeneration (pcd/pcd) mutants were implanted with chronic electromyogram (EMG) electrodes in the hamstring and quadriceps muscle groups of the right hindlimb. 2. EMGs were recorded in each of the mice during spontaneous activity before and after intraperitoneal injections of 0.3 ml harmaline (10 mg/kg). Spectral analysis was used to quantify the amplitude and frequency of tremor found in the EMGs after harmaline administration. Normal mice responded to harmaline with strong, continuous 11- to 14-Hz tremor. Mutants from the pcd/pcd strain also reacted with continuous tremor, but of lower amplitude and frequency. In contrast, nr/nr mutants exhibited intermittent paroxysmal tremor lasting for only a few seconds, and lc/+ mutants showed no evidence of tremor whatsoever. 3. In order to detect covert tremor that was possibly not revealed by focal intramuscular EMG recordings, several mutant and normal mice were also tested on a suspended platform to which an accelerometer was attached. The results confirmed the findings from EMG recordings. 4. An incidental observation made during the course of this study was that harmaline tremor disappeared from the normal mouse during swimming and reappeared when the animal was withdrawn from the water. 5. Although Purkinje cells appeared to increase both the depth of modulation and the frequency of tremor, the inhibitory action of the cerebellar cortex does not seem to be essential for the generation of tremor. 6. Parasagittal cerebellar sections of the normal, wild-type mice and the three strains of cerebellar mutant mice of various ages were stained with cresyl violet and examined for Purkinje cell degeneration. Purkinje cell degeneration was found to be complete in the pcd/pcd and lc/+ strains. Although an initial examination of parasagittal sections of the nr/nr strain failed to find any surviving Purkinje cells, further examination of sections cut in the coronal plane revealed small clusters of Purkinje cells in the vermal area of the posterior lobe. 7. The retrograde transport of wheat-germ-agglutinin-conjugated horseradish peroxidase (WGA-HRP) pressure-injected into the cerebellar cortex was used to study the olivocerebellar projections in the wild-type mice and the three strains of cerebellar mutant mice.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2005

Score-celebration injuries among soccer players: a report of 9 cases.

BACKGROUND: Professional and amateur soccer players often perform dramatic on-field feats of celebration after scoring a goal. Injuries may occur during these activities. PURPOSE: With the aim of preventing such "score-celebration injuries" in the future, the authors examine these events in professional soccer players and discuss potential avenues for prevention. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Over the course of 2 seasons (1996-1998), 152 soccer players were evaluated at an orthopaedic clinic for injuries incurred during matches. Nine players (6%) had injured themselves while celebrating after scoring goals in a match. The type of celebration, injury type, treatment, and mean duration of recovery were noted. RESULTS: Seven of the 9 patients were male professional soccer players with ages ranging between 17 and 29 years (mean age, 24 years). The injuries occurred when the playing ground was natural turf in 8 cases; most injuries occurred in the second half of the game. The types of celebration maneuvers were sliding (prone or supine) and sliding while kneeling in 5 cases, piling up on jubilant teammates in 3 cases, and being tackled while racing away in 1 case. Injuries included ankle, clavicle, and rib fractures; medial collateral ligament sprain; low back strain; hamstring and adductor muscle strain; quadriceps muscle sprain; and coccyx contusion. The mean duration for recovery was 6.2 weeks. Rival team players were usually not responsible for such trauma. CONCLUSION: Exaggerated celebrations after making a goal, such as sliding, piling up, and tackling a teammate when racing away, can result in serious injury. In addition to general measures for preventing soccer injuries, coaches and team physicians should teach self-control and behavior modification to minimize the risk of such injuries. More restrictive rules, which penalize such behavior, may assist in the prevention of score-celebration injuries.

Adolescent↗

PubMedDate not supplied

Neuromuscular performance in normal and anterior cruciate ligament-deficient lower extremities.

The neuromuscular function of the lower extremity in 40 normal and 100 anterior cruciate ligament-deficient volunteers was evaluated by physical examination, KT-1000 arthrometer measurements, isokinetic strength and endurance testing, subjective functional assessment, and an anterior tibial translation stress test. A specially designed apparatus delivered an anteriorly directed step force to the posterior aspect of the leg while anterior tibial translation was monitored and electromyographic signals were recorded at the medial and lateral quadriceps, medial and lateral hamstrings, and gastrocnemius muscles. Testing was done at 30 degrees of knee flexion with the foot fixed to a scale to monitor weightbearing, while the tibia remained unconstrained. Results indicate that muscle timing and recruitment order in response to anterior tibial translation are affected by anterior cruciate ligament injury. These alterations in muscle performance change with time from injury, correlate with an individual's physical activity level, affect subjective functional parameters, and are directly related to the degree of dynamic anterior tibial laxity seen with stress testing.

Adult↗

PubMedDate not supplied

Semitendinosus augmentation of acute patellar tendon repair with immediate mobilization.

We report four cases of acute midsubstance rupture of the patellar tendon that were treated with primary surgical repair along with semitendinosus autograft augmentation. The goal of this treatment was to allow immediate mobilization of the knee with a single operative procedure. We also demonstrate a technique for determining patellar position intraoperatively. Patients were tested for functional performance at an average final followup of 40 months (range, 20 to 66) including hamstring and quadriceps muscle strength evaluation, completion of a functional questionnaire, functional test performance, range of motion assessment, and patellar tendon length measurement. In evaluating the results, all cases were essentially identical to the nonoperated side, except one knee that had multiple associated ligament injuries. The multitude of injuries to this knee are likely the cause of the discrepancy. Immediate midsubstance patellar tendon repair with semitendinosus augmentation allowed immediate mobilization, which decreased the recovery period and improved the outcome of rehabilitation. Furthermore, a second surgery for hardware removal was not needed. These two factors--early and improved rehabilitation and the decreased chance of a second surgery--affect the cost of treatment of this injury. All isolated patellar tendon injuries in the study had excellent function at followup. For these reasons, we recommend this procedure for acute patellar tendon ruptures.

Adult↗

PubMed1987

Spinal cord stimulation for amelioration of spasticity: experimental results.

Fourteen cats underwent 500-g/cm dorsal impact injuries to the spinal cord and the placement of stimulating electrodes above and below the level of injury at T8. After recovery from the surgical procedure and the development of spasticity, each animal participated in several trials of spinal cord stimulation (SCS). Cord stimulation was provided above or below the level of injury using currents of less than 0.75 mA at 100 Hz. Electromyogram changes in hamstring and quadricep muscles (during spasms induced by dorsiflexion of the paw) were monitored. All animals showed complete paraplegia and, at 3 weeks, severe spasms. Spasticity was aggravated by SCS delivered above the level of injury. Spasms were markedly suppressed by monopolar stimulation delivered below the level of the lesion. Effects were maximal with the negative electrode applied to the cord and were slightly less with reversal of polarity. Muscle excitation was seen before diminution of spasms when bipolar currents were used. All effects lasted only as long as currents were delivered. These animal trials suggest that the effects of SCS are directly related to the current and its type. Beneficial effects were seen only when currents were delivered below the level of injury; this suggests that SCS activates local inhibitory processes or depolarizes local excitatory pathways. The poor results with bipolar stimulation do not support action on a multisynaptic cord system in short term stimulation.

Animals↗