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PubMed2001

[Isokinetic concentric dynamometry of knee flexors and extensors in young male].

Objective. To investigate the effects of different moving speeds on isokinetic dynamometry of knee flexors and extensors, and to provide normative data for comparative purposes in strength evaluations. Method. Thirty healthy male were tested at 60, 180, and 240 deg/sec angular velocities using a REV9000 testing and rehabilitation system. Result. Both PT (peak torque) and PT/BW (peak torque/body weights) showed significant differences (P< 0.01, P< 0.05) between flexors and extensors, and declined significantly with increased speed (P< 0.001). Peak torque differences between dominant and nondominant knee (Di%) was 10%. TPT (time to peak torque) tended to decrease as moving speeds increased (P< 0.001). APT (angle of peak torque) were 50%-70% for quadriceps, and 32%-45% for hamstrings; H/Q (hamstrings peak torque/quadriceps peak torque) was 50%-60%; WF (work fatigue) was 65%. Conclusion. The results provided a reference for strength evaluations in space medicine and space physiology, especially under simulated weightlessness and microgravity.

Aerospace Medicine↗

PubMed1998

Mechanisms of anterior cruciate ligament neovascularization and ligamentization.

Columbia-Rambouillet cross-bred sheep were used to study the revascularization and ligamentization process of anterior cruciate ligament (ACL) reconstruction over a 6-month period using basic histology, immunohistochemistry, and electron microscopy. The reconstruction technique studied was a quadruple-hamstring, interference screw fixation technique. Further, these specimens, after retrieval at 6, 12, and 26 weeks, were compared with human arthroscopic 'second looks' and with 10 en bloc specimens obtained when a cruciate-sacrificing total knee replacement was performed. The study showed that, with this reconstruction technique, Sharpey's fibers were seen at 6 weeks in both sheep and human specimens. The intratunnel specimens showed proliferative chondrification, then ossification of the matrix. Intra-articular neovascularization, ligamentization, and junction ossification occurred. Myoblasts or smooth muscle cells appear to mediate the ligamentization as evidenced in electron microscopy by proliferate collagen manufacture. These myoblasts were seen in both the healing sheep and human second looks, but not seen in mature ACL grafts or in normal ACLs. At 6 months postoperatively, the sheep ACL reconstruction appeared clinically, histologically, and immunohistochemically indistinguishable from the normal sheep ACL. A correlation of this work with published animal studies in which biomechanical testing was performed and with human 'second looks' would imply that an ACL reconstruction may be vulnerable during this period of neovascularization and ligamentization.

Adult↗

PubMed1993

The use of hamstring tendons for anterior cruciate ligament reconstruction. Technique and results.

We feel that some of the current prejudice against use of hamstring tendon grafts for ACL reconstruction has not been justified if one critically reviews the literature. In this article, we have tried to provide the reader with our current indications, present our current surgical technique, and review some of the outcome studies involving use of the hamstring tendons for ACL reconstruction. We also feel that some of the poor results of hamstring tendon ACL reconstructions previously reported resulted from the use of inadequate strength grafts (single-stranded grafts) and lack of rigid fixation on both ends of the graft (usually secondary to inadequate graft length). We feel that the technique described in this article addresses both of these issues. It is our clinical impression that, in appropriately selected patients, this technique produces stability and functional outcome similar to that obtained with patellar tendon grafts but results in less postoperative pain, a quicker return of quadriceps muscle function, and less donor site morbidity.

Animals↗

PubMed2000

Assessment of hip rotation after gait improvement surgery in cerebral palsy.

Sixteen children with diplegic type of cerebral palsy and spastic internal rotation gait were evaluated using gait analysis before and an average of 3 years after multiple soft tissue surgery. Significant correction of the internal rotation gait was observed after multi-level soft tissue surgery which included medial hamstring lengthening in all cases. Our results suggest that for children with spastic internal rotation gait, multi-level soft tissue surgery effectively corrects the dynamic internal rotation gait in the absence of fixed bony rotational deformities.

Adolescent↗

PubMed2005

[Reconstruction of the anterior cruciate ligament: comparison of patellar bone-tendon-bone and hamstring tendon graft methods. Part 2. Short-term evaluation of the hamstring tendon graft technique with use of the Rigidfix system].

PURPOSE OF THE STUDY: The high number of patients with femoropatellar complaints following ACL reconstruction with bone-tendon-bone (B-T-B) autograft led us to use and subsequently evaluate hamstring tendon grafts fixed with the Rigidfix system. In this study we present the evaluation of short-term results. MATERIAL: We evaluated 85 patients (51 male and 34 female) at an average follow-up of 14 months. The average age of the group was 29.7 years (range, 16 to 59 years). In 46 patients we treated the right knee and in 39 patients the left knee. Fifty-five patients in this group also had an associated injury to the soft knee tissues. For reconstruction, a semitendinosus tendon graft was used in 56 knees and a semitendinosus-gracilis tendon graft in 29 patients. METHODS: The operation was carried out with tourniquet application to the extremity in a flexed position. The tendon of the semitendinosus muscle was harvested through an oblique incision and, in some cases, when its width and length was not sufficient for graft construction, the gracilis muscle tendon was harvested too. The graft, at least 75 mm by 8 mm in size, was prepared on a graft board. After having drilled the both tunnels, the femoral Rigidfix reamer was inserted in a routine manner and protective sleeves for Rigidfix cross pins were introduced. With the extremity in semiflexion, the inserted graft was fixed to the cortical bone by absorbable cross pins on the femur and absorbable interference screws on the tibia. The postoperative treatment involved procedures as in the B-T-B technique. RESULTS: The group was evaluated by the Lysholm score system, with an average of 84.3 scores achieved. The men showed better outcomes than women, i. e., 85.7 and 81.4, respectively. The scores in the patients with a single tendon did not differ significantly from the patients with a combined tendon (semitendinosus, 83.2 vs. semitendinosus-gracilis, 84.2), nor did they greatly differ between the patients with injury to ACL alone and those with ACL and associated soft tissue injuries (ACL, 83.9 vs. ACL+ associated injury, 85.5). Most of the patients (94 %) were satisfied with the outcome of treatment. The complications involved thrombosis of the operated lower extremity in three patients and repeat surgery for hematoma in two patients. Knee instability was found in five patients. One graft failed to restructure and incorporate, in two knee tunnels were incorrectly centered and two grafts ruptured due to trauma. Three of these patients underwent repeat surgery. DISCUSSION: Our results, as evaluated by the Lysholm score system, were in agreement with those of other authors. We did not find any difference in knee stability between the patients treated by the hamstring tendon technique and those undergoing reconstruction with a patellar B-T-B autograft. However, the patients with hamstring tendon reconstruction reported a considerably lower number of femoropatellar problems. CONCLUSIONS: ACL reconstruction with a hamstring tendon autograft fixed with the Rigidfix system is a suitable alternative technique to ACL reconstruction carried out with a patellar B-T-B graft. It provides equal knee stability but has significantly lower donor site morbidity. It is suitable for patients who have contraindications for the B-T-B technique and in persons practicing little or no sports.

Adolescent↗

PubMed1989

Electromyographic study of the anterior cruciate ligament-hamstrings synergy during isometric knee extension.

The purpose of this investigation was to determine the role the hamstrings group may play in augmenting passive articular mechanisms during activity in which anterior drawer force may detrimentally affect the anterior cruciate ligament (ACL). Nine male subjects performed non-weight-bearing isometric knee extension at 10% increments of maximum voluntary contraction (MVC). Electromyographic (EMG) signals were detected and recorded from the vastus lateralis, vastus medialis oblique, vastus medialis longus, and the long head of the biceps femoris. The EMG signals were rectified and integrated over 1000 ms and normalized to subject-specific values. The data were subjected to a repeated-measures analysis of variance. The results demonstrated that expected significant increases in quadriceps excitation accompanied increases in knee extensor torque. Hamstrings excitation was not found to change significantly (total change = 3.4%). It was concluded that functionally adequate knees do not require posterior drawer force in excess of that provided passively by articular structures.

Adult↗

PubMed1983

Lower extremity electromyographic analysis of running gait.

Onset of firing for the quadriceps, hamstrings, and gastroc soleus groups during running, both on a treadmill and over ground, was determined in seven normal adult male subjects. Surface and wire electrode data were collected simultaneously from 959 individual gait cycles. The mean velocity over ground was 274 +/- 38 m/minute, with a mean cadence of 171 +/- 14 steps/minute. The treadmill was set at 107 m/minute (4 miles/hour), and the subjects' mean cadence was 147 +/- 11 steps/minute. Over ground, the mean swing/stance ratio was 70/30 +/- 3%, and that for the treadmill was 60/40 +/- 6%. Like muscle groups on the right and left showed a mean difference in onset of muscle activity of 1.3% (+/- 4.6%) when measured during a minimum of ten cycles per subject for each test condition. The average difference in time of onset between the surface and wire electrodes was 2% (SD +/- 4.9%) on the treadmill and 1.5% (SD +/- 3.7%) for over-ground running. These differences are not statistically significant. Surface and wire electrode data have been determined to be equivalent only for regional synergistic muscle groups and should not be extrapolated to compare functions of individual muscles within those groups.

Adult↗

PubMedDate not supplied

Phase I design and evaluation of an isometric muscle reeducation device for knee osteoarthritis rehabilitation.

Our long-term goal is to improve adherence to a home-based isometric program for rehabilitation of knee osteoarthritis (OA) using a force-biofeedback device (Isopad). Our goal for Phase I was to design and evaluate an Isopad-based program in a supervised clinical setting. Our subjects were five patients with knee OA of Kellgren stage II or greater. A capacitive force sensor was tested for accuracy, repeatability, and durability. An Arthritis Foundation home-based isometric program inspired the Isopad design. The Isopad provided visual and auditory feedback instantaneously and continuously about force generated between the ankles. The five subjects completed a supervised 8-week progressive isometric program using the Isopad. Absolute isolated quadriceps and hamstring torques were quantified with a dynamometer, and patients completed a self-assessment of symptoms (Western Ontario and McMaster Universities Osteoarthritis Index). The capacitive sensor accuracy error averaged 10% and repeatability 4%. Cognitively intact subjects used the Isopad successfully for isometric progressive resistance training. Quadriceps and hamstrings absolute torques increased an average of 30%. Patients reported decreased functional complaints (Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index). All changes were trends. The Isopad helped subjects with knee OA adhere to a supervised isometric program and meet progressive strength targets. The next-generation Isopad will be employed in a home-based program.

Electromyography↗

PubMed2005

Range of motion in children with spastic diplegia, GMFCS I-II compared to age and gender matched controls.

Measurements of passive range of motion are often used to define the degree of muscle shortening in children with spastic diplegic cerebral palsy. However, little is known about the expected values of passive range of motion measurements in children with spastic diplegia and how these might differ from age and gender matched norms taken from the same population. Therefore, the purpose of this study was to compare eight lower limb measurements of sagittal plane passive range of motion in 22 children with spastic diplegia, GMFCS I to II, with 22 matched controls. Children with spastic diplegia had minimal hip extension loss, but reduced hamstring length, with popliteal angle averaging -59.2+/-10.6 degrees (control -38.8+/-13.4 degrees, p < 0.001) and SLR averaging 52.7+/-10.2 degrees (control 75.8+/-11.1 degrees, p < 0.001). Ankle dorsiflexion with knee extension averaged -2.5+/-8.4 degrees in children with spastic diplegia (control 8.6+/-6.8 degrees, p < 0.001). These data confirmed that children with mild spastic diplegia had some restriction in passive range of motion compared to controls but that there was considerable variability between individuals.

Adolescent↗

PubMed2001

Patellar tendon vs. doubled semitendinosus and gracilis tendon for anterior cruciate ligament reconstruction.

In a prospective study on ACL reconstruction we treated 17 patients with a "central third-bone-patellar tendon-bone" autograft (PT group) and 32 patients with a doubled semitendinosus/doubled gracilis autograft (HS group). Patients were reviewed at 6 weeks, and at 3, 6, and 12 months postoperatively and the groups compared. Up till 6 months, the KT-1000 side-to-side difference was significantly greater in the HS group (P<0.05) and at 6 and 12 months isokinetic hamstrings strength was lower (P<0.05). No significant differences were noted at any stage with respect to quadriceps strength, functional scores, range of motion, or swelling.

Adolescent↗

PubMed2004

Three-dimensional computed tomography evaluation of semitendinosus harvest after anterior cruciate ligament reconstruction.

PURPOSE: Recent studies have shown the regeneration potential of hamstring tendons harvested for anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to evaluate the morphology of the regenerated semitendinosus tendon using 3-dimensional (3-D) images of volume-rendered multidetector helical computed tomography (MD-CT). TYPE OF STUDY: Retrospective study on a convenient sample of patients. METHODS: Eight patients were selected from those with a minimum 2-year follow-up evaluation after ACL reconstruction with hamstring tendons. The harvest site of the semitendinosus tendon was evaluated using 3-D CT, in addition to magnetic resonance imaging (MRI) analysis, at an average of 37 months (range, 27 to 47 months) after surgery. RESULTS: In 5 of 8 patients, MRI evaluation indicated recurrence of the region with the same signal intensity as the native at the harvest site of the semitendinosus tendon. In these patients, the 3-D image of MD-CT visualized the stringy tendinous tissue regenerated at the harvest site originating from the semitendinosus muscle belly and running in the same pathway as the native tendon. However, the distal part attached into the medial surface of the popliteal fascia. By contrast, in the involved sides of the remaining 3 patients with no detection on MRI, the 3-D CT image showed no tendinous tissue at the harvest site. The remnants of the semitendinosus had reduced or fused into the muscle belly of the semimembranous. CONCLUSIONS: Using the 3-D CT technique, we could first depict the distinct morphology of the regenerate at the harvest site of the semitendinosus tendon. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Adolescent↗

PubMed2004

Total knee replacement in patients with multiple sclerosis.

Total knee replacement was performed on two patients with Multiple sclerosis. Severe hamstring spasticity was encountered in both patients in the immediate post-operative period requiring further surgery. Both patients remain ambulatory at follow-up. The disease, and its implications in patients warranting total joint replacement are discussed.

Aged↗

PubMed1984

Effect of electrical stimulation on spasticity in hemiparetic patients.

Cyclical electrical stimulation has been applied to 10 hemiparetic patients with clinical signs of knee joint spasticity. The programme included 30 minutes of stimulation to the hamstrings followed by another 30 minutes of stimulation to the hamstrings and quadriceps. None of the patients experienced increased spasticity. The reduction in spasticity ranged from none to substantial with some other beneficial side-effects. No conclusions could be drawn as to whether hamstring stimulation is preferred to combined stimulation or to quadriceps stimulation alone. It is suggested that small portable stimulators be introduced for chronic use in spastic patients after an optimum stimulation regimen is individually established for each patient.

Adolescent↗

PubMed1999

Gait pattern in patients with spastic diplegic cerebral palsy who underwent staged operations.

Fifteen patients with spastic diplegic cerebral palsy (CP) were monitored for a mean length of 9.5 years after they underwent staged operations and were evaluated by gait analysis, including joint motion in the sagittal plane and the ground reaction force (GRF) in three dimensions. Results showed an increased hip flexion (132%) at midstance, a reduction of peak knee flexion (PKF) during swing (45%) accompanied by an augmented time of PKF during swing (50%), and an increased dorsiflexion of the ankle during swing (293%) as well as its time during the gait cycle, in comparison with normal values. Moreover, significant decreases of the vertical GRF at the terminal stance and the forward and backward GRF were present. Additionally, it was found that a bilateral popliteal angle < 20 degrees is acceptable in spastic CP. Staged operations gave unpredictable results in the correction of contracture of the hamstrings, the Achilles tendon, and the iliopsoas. The authors are convinced that gait analysis is useful in evaluating these patients and enhances the results of operative treatment, and they have since changed their approach toward multilevel simultaneous corrections.

Adolescent↗

PubMed1997

Lumbar root stimulation for restoring leg function: results in paraplegia.

We have implanted an intradural array of 12 tripolar electrodes on the anterior roots L2-S2, left and right, at cauda equina level, in a 33-year-old woman with a complete T9 cord lesion of 3 years' duration. They are driven by an implanted multiplexed stimulator system using radio frequency (RF) power and control signals. All channels generate movements, in patterns that might be predicted from the known anatomy of the cauda equina. In particular, stimulation of L2 and L3 gives hip adduction; L3, L4, and L5 gives quadriceps femoris movements; L5, S1, and S2 gives hamstrings movement; and S1 and S2 give plantar flexion. Stimulation of L5 gives mixed movements at the ankle. Surprisingly, stimulation of the L2 roots has not given strong hip flexion. Responses have been stable. Some thresholds have varied, probably as a result of tissue encapsulation. The moment generated within each degree of freedom of the legs has been measured for each root, using a specially designed multimoment measurement apparatus. For several roots, a movement of lower threshold may be accompanied by a second movement of higher electrical threshold, suggesting that different muscles may have fiber populations that differ in their diameter or their location in the root. The use of stimulus forms that enable selective anodal block may, in the future, enable separation of two distinct movements from a single motor root.

Adult↗

PubMed1995

Foot contact pattern following selective dorsal rhizotomy.

Fourteen ambulatory patients with spastic cerebral palsy were evaluated prior to and 6 months following selective dorsal rhizotomy. An instrumented gait analysis identified significant improvements in foot contact patterns, velocity and stride length. The high incidence of postoperative valgus, excessive dorsiflexion and persistent knee flexion during gait was attributed to significant weakness and hypotonicity in the plantar flexors, as well as residual hamstring spasticity (p < 0.05). Sectioning of fewer S-1 rootlets may preserve plantar flexion strength and enhance stance stability by preventing postoperative increases in dorsiflexion and knee flexion. Orthotic prescription for ankle instability should be a routine postoperative consideration.

Adolescent↗

PubMedDate not supplied

Insufficiency of the hip adductor after anterior obturator neurectomy in 42 children with cerebral palsy.

Forty-two children with cerebral palsy treated between 1970 and 1982 for correction of adduction and internal rotation of the hip were studied. According to the combined procedures and the effects of surgical manipulations, two groups were evaluated. The results of release of the adductor longus and gracilis without anterior obturator neurectomy were satisfactory when combined with proximal release of medial hamstrings. Hypertonicity in hip adduction was relieved. In cases of loss of function of the adductor brevis with anterior obturator neurectomy, the results were not satisfactory, and hyperabduction of the hip was inadequate. The adductor brevis plays an important role in stability of the hip.

Adolescent↗

PubMed2006

Kinematics and electromyography of landing preparation in vertical stop-jump: risks for noncontact anterior cruciate ligament injury.

BACKGROUND: Biomechanical analysis of stop-jump tasks has demonstrated gender differences during landing and a potential increase in risk of noncontact anterior cruciate ligament injury for female athletes. Analysis of landing preparation could advance our understanding of neuromuscular control in movement patterns and be applied to the development of prevention strategies for noncontact anterior cruciate ligament injury. HYPOTHESIS: There are differences in the lower extremity joint angles and electromyography of male and female recreational athletes during the landing preparation of a stop-jump task. STUDY DESIGN: Controlled laboratory study. METHODS: Three-dimensional videographic and electromyographic data were collected for 36 recreational athletes (17 men and 19 women) performing vertical stop-jump tasks. Knee and hip angular motion patterns were determined during the flight phase before landing. RESULTS: Knee and hip motion patterns and quadriceps and hamstring activation patterns exhibited significant gender differences. Female subjects generally exhibited decreased knee flexion (P = .001), hip flexion (P = .001), hip abduction (P = .001), and hip external rotation (P = .03); increased knee internal rotation (P = .001); and increased quadriceps activation (P = .001) compared with male subjects. Female subjects also exhibited increased hamstring activation before landing but a trend of decreased hamstring activation after landing compared with male subjects (P = .001). CONCLUSION: Lower extremity motion patterns during landing of the stop-jump task are preprogrammed before landing. Female subjects prepared for landing with decreased hip and knee flexion at landing, increased quadriceps activation, and decreased hamstring activation, which may result in increased anterior cruciate ligament loading during the landing of the stop-jump task and the risk for noncontact ACL injury.

Adult↗