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PubMed1989

Importance of the iliopsoas muscle in soft-tissue surgery of hip deformities in cerebral palsy children.

Twenty cerebral palsy patients who had undergone soft-tissue surgery at the hip (adductor tenotomy, medial lengthening of the hamstrings) were compared with a matched group of another 20 patients with a similar age range and findings and with additionally performed iliopsoas release, 2 or more years after surgery. Extension deficits of the hip did not improve with the addition of iliopsoas release. Internal rotation deformities showed equal improvement in both groups; the influence of the iliopsoas procedure was not significant. Adduction deformities, as documented on roentgenograms of the hip, showed significant improvement, however. Postural anomalies were not essentially influenced by iliopsoas release. Hip dislocations and subluxations, as assessed by the CE angles, were positively influenced by additional iliopsoas release; however, more effective improvement was obtained with ischiocrural elongation.

Adolescent↗
PubMed2006

Near-infrared light and expectancy effects on maximal isokinetic strength performance: a randomized, double-blind, placebo-controlled study.

Infrared-light radiation has recently and effectively been applied to solving a wide range of problems in the sport sciences. However, few investigations have focused on the potential performance-enhancing properties of near-infrared (NIR)-light stimulation, and none have examined its effects on muscle strength. As such, the purpose of this investigation was to determine the extent to which NIR light influenced the maximal isokinetic strength of the quadriceps and hamstrings. Forty-eight college students participated in the study. Four experimental conditions were created: (a) an active group with expectancy instructions, (b) an active group without expectancy instructions, (c) a placebo group with expectancy instructions, and (d) a placebo group without expectancy instructions. Individuals in active conditions were outfitted in NIR light-emitting bandages, T-shirts, and socks, whereas those in placebo conditions were outfitted in the same attire but without active NIR light. Maximal isokinetic torque values of the quadriceps and hamstrings were measured. Results indicated that the active group without expectancy instructions exhibited enhanced isokinetic strength for the hamstrings at a contractile speed of 180 degrees x s(-1) as compared with the placebo groups. With continued replication of our initial exploratory findings, infrared equipment might emerge as a promising means for performance enhancement.

Adolescent↗
PubMed1991

Evaluation of total knee arthroplasty using isokinetic testing.

Although total knee arthroplasty (TKA) has been studied extensively, objective muscle testing has not been reported. Isokinetic testing of 68 patients with degenerative joint disease scheduled for unilateral TKA revealed that marked muscular deficits in flexion and extension were present preoperatively in the involved knee. Postoperatively, hamstring peak-torque values were able to attain strength levels of the uninvolved knee within the period of seven to 12 months after surgery, whereas the quadriceps mechanism still showed a residual deficit at two years follow-up evaluation. In addition, the ratio of flexion to extension peak torques in the operated knee returned to normal values as the quadriceps mechanism was rehabilitated. A comprehensive evaluation system consisting of Cybex II isokinetic testing, gait mat analysis, and the Hospital for Special Surgery knee rating scale is also presented. Isokinetic testing correlated well with gait analysis. Patients with a nearly balanced quadriceps-to-hamstring ratio walked with a more symmetrical gait pattern. The knee rating scale was less reliable in assessing functional outcome. Functional testing and evaluation at the authors' institution has provided an important source of objective information that allows better planning and evaluation of TKAs. These isokinetic studies enable more critical planning of the rehabilitation program. Hamstring or quadricep exercises may be emphasized as required. The authors conclude that a balanced hamstring to quadriceps mechanism is needed for resumption of normal gait.

Biomechanical Phenomena↗
PubMed2004

Longitudinal study comparing sonographic and MRI assessments of acute and healing hamstring injuries.

OBJECTIVE: We compared sonography and MRI for assessing hamstring injuries in professional football players (Australian football) 3 days, 2 weeks, and 6 weeks after an injury and identified imaging characteristics at baseline that may be useful in predicting the time needed for return to competition. MATERIALS AND METHODS: Sixty men who are professional football players presented with suspected acute hamstring strain underwent sonography and MRI within 3 days of injury; those who were injured returned 2 and 6 weeks later for follow-up MRI and sonography. Two radiologists interpreted either the MR images or the sonograms and were blinded to the results of the other technique. The following six parameters were measured at each assessment: the muscle injured, the site of injury within the muscle, the longitudinal injury length (expressed in millimeters), the cross-sectional injured area (expressed as a percentage), and the presence of interand intramuscular hematoma. RESULTS: At baseline, MRI identified abnormalities in 42 (70.0%) of 60 patients, whereas sonography found abnormalities in 45 (75%) of 60. At 2 weeks, 29 (59.2%) of 49 scans showed abnormalities on MRI and 25 (51.0%) of 49 showed abnormalities on sonograms. Of those players who were injured at baseline, 15 (35.7%) of 42 and 10 (22.2%) of 45 still showed abnormal results on scans at 6 weeks on MRI and sonography, respectively. However, all but one player had returned to competition. The biceps femoris was the most commonly injured muscle and the musculotendinous junction was the most common site of injury. Injuries appeared significantly larger on MRI than on sonography at all time points. Our analysis showed that at baseline, the longitudinal length of hamstring tear on MRI had the highest statistical correlation with recovery (r = 0.58, p < 0.0001) and was the best radiologic predictor for return to competition. CONCLUSION: Sonography is as useful as MRI in depicting acute hamstring injuries and because of lower costs may be the preferred imaging technique. However, MRI is more sensitive for follow-up imaging of healing injuries. The longitudinal length of the strain as measured on MRI is a strong predictor for the amount of time needed until an athlete can return to competition.

Adult↗
PubMed2002

Anterior cruciate ligament replacement: comparison of bone-patellar tendon-bone grafts with two-strand hamstring grafts. A prospective, randomized study.

BACKGROUND: The purpose of this investigation was to evaluate replacement of a torn anterior cruciate ligament with either a bone-patellar tendon-bone autograft or a two-strand semitendinosus-gracilis autograft to compare the results of clinical testing, patient satisfaction, activity level, functional status, and muscle strength. METHODS: Fifty-six patients with a torn anterior cruciate ligament were enrolled in a prospective, randomized, controlled study. Twenty-eight underwent reconstruction with a bone-patellar tendon-bone autograft, and twenty-eight were treated with a two-strand semitendinosus-gracilis autograft. Patients were followed for an average of thirty-nine months (range, thirty-six to fifty-seven months). At the time of final follow-up, twenty-two patients in each group were evaluated in terms of clinical test findings, patient satisfaction, activity level, functional status, and isokinetic muscle strength. RESULTS: The objective outcome of replacement of the torn anterior cruciate ligament with a bone-patellar tendon-bone graft was superior to that obtained with a two-strand semitendinosus-gracilis graft. At the three-year follow-up interval, the patients in whom a hamstring graft had been used had an average of 4.4 mm of increased anterior knee laxity compared with the laxity of the contralateral, normal knee, whereas the patients in whom a bone-patellar tendon-bone graft had been used had an average of 1.1 mm of increased knee laxity. Fourteen percent (three) of the twenty-two patients with a hamstring graft had a mild pivot shift, and 27% (six) had a moderate pivot shift. Only 14% (three) of the twenty-two patients with a bone-patellar tendon-bone graft had a mild pivot shift, and none had a moderate pivot shift. At the same follow-up interval, the patients in whom a hamstring graft had been used had significantly lower peak knee-flexion strength than those who had a bone-patellar tendon-bone graft (p = 0.039). In contrast, the two treatments produced similar outcomes in terms of patient satisfaction, activity level, and knee function (ability to perform a one-legged hop, bear weight, squat, climb stairs, run in place, and duckwalk). CONCLUSIONS: After three years of follow-up, the objective results of anterior cruciate ligament replacement with a bone-patellar tendon-bone autograft were superior to those of replacement with a two-strand semitendinosus-gracilis graft with regard to knee laxity, pivot-shift grade, and strength of the knee flexor muscles. However, the two groups had comparable results in terms of patient satisfaction, activity level, and knee function.

Adolescent↗
PubMedDate not supplied

A prospective randomized comparison of patellar tendon versus semitendinosus and gracilis tendon autografts for anterior cruciate ligament reconstruction.

Seventy patients with patellar tendon or hamstring tendon autografts for single-incision anterior cruciate ligament reconstruction were evaluated at least 2 years after surgery. All reconstructions were performed by the same surgeon, and metal interference screws were used for fixation of all grafts. No significant differences were noted between groups for Lysholm score, reduction in activity, KT-1000 arthrometer findings, quadriceps muscle size, return to sports, or ability to jump and do hard cuts and pivots. Significantly more patients in the patellar tendon group had patellofemoral pain at 6 months after surgery than did the hamstring tendon patients (48% versus 20%), and at last follow-up the incidence of patellofemoral pain was 42% and 20%, respectively. Fourteen patients in the patellar tendon group and seven in the hamstring tendon group had loss of motion (approximately 5 degrees ). Four patients (two in each group) had treatment failures and their results were not included in the clinical examination data. At 2 years' follow-up, 97% of patients with patellar tendon grafts and 100% of patients with hamstring tendon grafts rated their results as good or excellent. We found that hamstring tendon grafts performed similarly to patellar tendon grafts, although fewer patients in the hamstring tendon group had patellofemoral pain and loss of motion.

Adolescent↗
PubMed1994

[Incidence of complaints about heel-, knee- and back-related discomfort among Danish children, possible relation to short muscles].

Four hundred and fifty-nine children and adolescents from third, sixth and ninth classes in seven schools on Funen were questioned in 1991. Seven percent had complaints from back and knee, and 3% from the heel. When the hamstrings were so short that one knee had an extension deficit gently measured to more than 40 degrees, when the hip was flexed 90 degrees, the incidence of back pain rose significantly to 15%. Furthermore 18% had complaints from the knee and 35% from the heel when the passive range of motion of the foot was less than 0 degrees of dorsiflexion measured with the knee extended. As 75% of the boys and 35% of the girls over age ten have short hamstrings and 13% of both sexes have short Achilles tendons, it is recommended that school children be involved in a daily stretching programme in order to diminish the complaints from the extremities often seen in this group.

Adolescent↗
PubMed2000

The variation in the orientations and moment arms of the knee extensor and flexor muscle tendons with increasing muscle force: a mathematical analysis.

The orientations and moment arms of the knee extensor and flexor muscle tendons are evaluated with increasing values of muscle force during simulated isometric exercises. A four-bar linkage model of the knee in the sagittal plane was used to define the motion of the joint in the unloaded state during 0-120 degrees flexion. The cruciate and collateral ligaments were represented by arrays of elastic fibres, which were recruited sequentially under load or remained buckled when slack. A bi-articular model of the patello-femoral joint was used. Simple straight-line representation was used for the lines of action of the forces transmitted by the model muscle tendons. The effects of tissue deformation with increasing muscle force were considered. During quadriceps contraction resisted by an external flexing load, the maximum change in moment arm of the patellar tendon was found to be 2 per cent at 0 degree flexion when the quadriceps force was increased tenfold, from 250 to 2500 N. The corresponding maximum change in orientation of the tendon was 3 degrees at 120 degrees flexion. During hamstrings contraction resisted by an external extending load, the maximum change in moment arm of the hamstrings tendon was 8 per cent at 60 degrees flexion when the hamstrings force was increased tenfold, from 100 to 1000 N. During gastrocnemious contraction, the corresponding maximum change for the gastrocnemious tendon was 3 per cent at 0 degree. The orientations of the flexor muscle tendons in this range of force either remained constant or changed by 1 degree or less at any flexion angle. The general trend at any flexion angle was that, as the muscle force was increased, the moment arms and the orientations approached nearly constant values, showing asymptotic behaviour. It is concluded that experimental simulations of knee muscle action with low values of the externally applied load, of the order of 50 N, can provide reliable estimates of the relationships between muscle forces and external loads during activity.

Humans↗
PubMed1999

Effects of altering cycling technique on gluteus medius syndrome.

OBJECTIVE: We discuss how altering the cycling technique of a cyclist receiving periodic chiropractic care helped in the management of gluteus medius syndrome. CLINICAL FEATURES: A 24-year-old male amateur cyclist had numbness and tingling localized to a small region on the superior portion of the right buttock. The area involved demonstrated paresthesia to light touch sensory evaluation. The cyclist had received chiropractic adjustments 2 days before the onset of the symptoms. One week earlier, the patient began riding a new bicycle with different gearing than his previous one. Manual-resisted muscle testing created soreness in the lumbosacral area and buttocks. Trigger points were identified in the right gluteus medius. Standing lumbar spine flexion was 70 degrees, limited by tight hamstrings. INTERVENTION AND OUTCOME: Because the patient was already receiving periodic chiropractic care, no passive therapy was used. Patient education regarding the difference in gear selection in bicycles of a higher quality was provided. He was instructed to train in lower gears than he had previously used and to maintain a cadence of 70 to 90 revolutions of the pedals per minute. After 2 days, the paresthesia on the right buttock resolved. The trigger points were only mildly tender with minimal residual soreness of the involved muscles. CONCLUSION: Management of gluteus medius syndrome by altering the cadence and gear development for a bicyclist is discussed. Either frank or cumulative injury to the gluteus medius muscle is the typical etiologic factor for this syndrome. Repetitive strain of the patient's gluteus medius muscle as a result of poor cycling technique appeared to be the cause here. Knowledge of bicycle fitting, training techniques, and bicycle mechanics appeared necessary to resolve the problem.

Adult↗
PubMed1999

Adaptation of the walking pattern to uphill walking in normal and spinal-cord injured subjects.

Lower-limb movements and muscle-activity patterns were assessed from seven normal and seven ambulatory subjects with incomplete spinal-cord injury (SCI) during level and uphill treadmill walking (5, 10 and 15 degrees). Increasing the treadmill grade from 0 degrees to 15 degrees induced an increasingly flexed posture of the hip, knee and ankle during initial contact in all normal subjects, resulting in a larger excursion throughout stance. This adaptation process actually began in mid-swing with a graded increase in hip flexion and ankle dorsiflexion as well as a gradual decrease in knee extension. In SCI subjects, a similar trend was found at the hip joint for both swing and stance phases, whereas the knee angle showed very limited changes and the ankle angle showed large variations with grade throughout the walking cycle. A distinct coordination pattern between the hip and knee was observed in normal subjects, but not in SCI subjects during level walking. The same coordination pattern was preserved in all normal subjects and in five of seven SCI subjects during uphill walking. The duration of electromyographic (EMG) activity of thigh muscles was progressively increased during uphill walking, whereas no significant changes occurred in leg muscles. In SCI subjects, EMG durations of both thigh and leg muscles, which were already active throughout stance during level walking, were not significantly affected by uphill walking. The peak amplitude of EMG activity of the vastus lateralis, medial hamstrings, soleus, medial gastrocnemius and tibialis anterior was progressively increased during uphill walking in normal subjects. In SCI subjects, the peak amplitude of EMG activity of the medial hamstrings was adapted in a similar fashion, whereas the vastus lateralis, soleus and medial gastrocnemius showed very limited adaptation during uphill walking. We conclude that SCI subjects can adapt to uphill treadmill walking within certain limits, but they use different strategies to adapt to the changing locomotor demands.

Adaptation, Physiological↗
PubMed2006

Percentile values of isokinetic peak torque in children six through thirteen years old.

PURPOSE: The purpose of this study was to standardize an isokinetic testing protocol for quadriceps and hamstrings in children who are typically developing and are six through 13 years of age, to establish percentile charts of isokinetic peak torque strength for quadriceps and hamstrings by gender and age, and to determine the best predictors of strength for each of three testing speeds. METHODS: A total of 3587 children were tested for isokinetic knee strength according to our protocol on Biodex System II and III isokinetic dynamometers. Therapists participating in the study were trained on the protocol and inter-rater reliability was established. Both dominant and nondominant legs were tested at three speeds. Data were collected on peak torque, time to peak torque, and agonist/antagonist ratio. Data were also gathered on maturation level, gender, height, weight, leg length, laterality, and activity level to allow for investigation of correlations with peak torque. All data were entered in an Excel spreadsheet. RESULTS: Percentile charts of normal isokinetic muscle strength were generated using SPSS 12.0 for each age and gender at three speeds (60, 120, and 180 degrees per second). Stepwise regression analysis determined height to be the best predictor of peak torque for both quadriceps and hamstrings at all speeds. CONCLUSIONS: This study is the first to report normative peak torque values for quadriceps and hamstrings in children. By using a standardized testing protocol and normative data, clinicians will be able to assess the degree of muscle weakness as well as the effectiveness of intervention strategies.

Adolescent↗
PubMed2003

Outcome after reconstruction of the anterior cruciate ligament in athletic patients. A comparison of early versus delayed surgery.

We randomised 31 patients with acute tears of the anterior cruciate ligament (ACL) to receive either early (within 2 weeks) or delayed (8 to 12 weeks) reconstruction using a quadruple hamstring graft in order to determine if there was any functional advantage to early reconstruction. Outcome measures included return of knee movement, muscle dynamometry, International Knee Documentation Committee (IKDC) scores and Tegner activity levels. Two cases of symptomatic deep-venous thrombosis occurred in the early group. The mean range of movement was significantly greater at two weeks in the delayed group. Quadriceps muscle power was significantly better in the delayed group at 12 weeks (p < 0.05). These trends were evident at later time points, but were not statistically significant. One patient in each group had clinically significant knee stiffness at 52 weeks. IKDC scores and Tegner activity levels were not significantly different at 52 weeks. We conclude that there is no functional advantage to be gained by early reconstruction of the ACL.

Adolescent↗
PubMed2003

Biomechanics of the knee joint in deep flexion: a prelude to a total knee replacement that allows for maximum flexion.

A two-dimensional anatomically based mathematical model of the human knee joint was developed to understand its biomechanics in deep flexion. The model was used to determine the internal knee loads as it simulates isometric quadriceps and hamstring co-contractions at different flexion angles during deep squat. It was found that in order to achieve deep flexion, large muscle forces are required, resulting in large tibio-femoral contact forces. In deep flexion, the femoral contact point was located on the most proximal point of the posterior condyle, location which was not affected by the level of quad activation. Conversely, the location of the tibial contact point was highly affected by the level of quad activation. Both anterior and posterior fiber bundles of the posterior cruciate ligament were found to carry high loads when the knee is maximally flexed. These results point to the important role of the posterior cruciate ligament in this position, and suggest the necessity of retaining this ligament during total knee replacement (TKR) procedures that allows for maximum flexion angles. Furthermore, the present data provide an explanation why most TKR's do not allow deep flexion: while contact occurs on the most proximal points of the posterior condyles in normal knees, this portion of the condyles is not presently resurfaced when performing a TKR.

Adult↗
PubMed1989

Hydatid disease in Zimbabwe: a case report.

A case of multilocular hydatid cyst involving the hamstring compartment of the thigh is presented. The nature of the lesion was realised intraoperatively and histopathological examination confirmed the diagnosis of muscle hydatid disease. Although rarely recorded in the rural population of Zimbabwe, cystic hydatid disease should be in the list of differential diagnosis of any slowly growing, cystic occupying mass.

Diagnosis, Differential↗
PubMed2005

Atrophy of thigh muscles after meniscal lesions and arthroscopic partial menisectomy.

The purpose of this study was to investigate the atrophic pattern of the muscle groups and their individual muscles in the thigh after meniscal lesions and arthroscopic partial menisectomy. A total of 32 individuals (17 men and 15 women) who underwent arthroscopic knee surgery participated in this study. Their operated and non-operated thighs were scanned by magnetic resonance imaging to determine the volume of the quadriceps (QF), hamstring (HM), and adductors (AD). Compared with the non-operated limb, the volume of the QF was significantly lower in the operated limb; however, no significant difference was observed in the HM and AD. The volume of individual muscles of the QF, i.e. the rectus femoris (RF), vastus lateralis (VL), vastus intermedius (VI), and vastus medialis (VM), in the operated limb was significantly lower than the volume of those in the non-operated limb (P<0.01, all). Although the relative change in the VM was significantly higher than that of the RF (P<0.05), specific atrophy was not found among four individual muscles in the QF. We concluded that meniscal lesions and partial menisectomy induce atrophy in the QF only in the thigh, and that no specific atrophy, e.g. VM, seemed to occur within the individual muscles in the QF.

Adult↗