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PubMed1989

Modified posterior soft tissue release for management of severe knee flexion contracture.

A modified posterior soft tissue release has been used in treating severe flexion contracture of the knee in 30 patients (36 knees). The operative technique has been modified with respect to the skin incision, and lengthening of the medial hamstrings. It is performed without a tourniquet. Postoperative skeletal traction was applied with gradual increasing weight to rapidly correct residual deformity. The deformity was fully corrected in 30 knees. The only complication was superficial skin necrosis over a small area, which occured in two knees. In six knees, 10 degrees of flexion deformity persisted after treatment. In four additional knees, 10 degrees of flexion deformity recurred due to lack of continued therapy. The modified posterior soft tissue release operation gave good results without any serious complications.

Adolescent↗

PubMed2004

Graft-bone motion and tensile properties of hamstring and patellar tendon anterior cruciate ligament femoral graft fixation under cyclic loading.

PURPOSE: To assess longitudinal graft-bone motion and tensile properties of the femur-anterior cruciate ligament (ACL) graft fixation-ACL graft complex based on the hypothesis that there is little difference in graft-bone motion between suspensory and aperture hamstring ACL femoral graft fixation techniques, and between hamstring and patellar tendon ACL femoral graft fixation techniques. TYPE OF STUDY: In vitro biomechanical study using human cadavers. METHODS: The distal femur-ACL graft fixation-ACL graft complex was cyclically loaded between 50 and 250 N at 1 Hz for 1,000 cycles with the direction of the load applied parallel to the axis of the femoral bone tunnel. Graft-bone motion was measured indirectly using retroreflective markers and a video motion-analysis system. Tensile testing to failure was performed at 1 mm/sec for fixation techniques completing 1,000 cycles without fixation failure. RESULTS: Among the hamstring fixation techniques, 4 of 13 Bio-Interference screws (Arthrex, Naples, FL), 2 of 12 LinX HT fasteners (DePuy Mitek, Norwood, MA), and 1 of 11 TransFix cross-pins (Arthrex) failed before completing 1,000 cycles. Five of 13 patellar tendon grafts fixed with metal interference screws, and 2 of 12 patellar tendon grafts fixed with a plastic button and No. 5 sutures failed before completing 1,000 cycles. Suture/button fixation of patellar tendon grafts resulted in significantly more graft-bone motion than hamstring tendon grafts fixed using the Bone Mulch Screw (Arthrotek, Warsaw, IN), or interference screw fixation of patellar tendon and hamstring grafts. Otherwise, there was no significant difference in graft-bone motion among the various hamstring fixation techniques or the various hamstring fixation techniques and interference screw fixation of patellar tendon grafts. Maximum graft-bone displacement after cyclic loading was significantly greater for hamstring grafts fixed with the EndoButton and EndoButton Tape (Smith & Nephew Endoscopy, Andover, MA) compared with the other hamstring fixation techniques and interference screw fixation of patellar tendon grafts. All fixation techniques except hamstring tendon grafts fixed with the Bio-Interference screw achieved at least 59% of maximum graft-bone displacement after 20 cycles. Hamstring tendon grafts fixed with the EndoButton CL were significantly stronger than all other hamstring and patellar tendon fixation methods. Patellar tendon grafts fixed with interference screws and hamstring tendon grafts fixed with interference screws and the Bone Mulch Screw and TransFix were significantly stiffer than hamstring tendon grafts fixed with the EndoButton CL. CONCLUSIONS: There is no significant difference in graft-bone motion between aperture and suspensory femoral fixation methods when the stiffness of the femur-ACL graft fixation-ACL graft complex is similar. CLINICAL RELEVANCE: The small differences in graft-bone motion reported in our study provide further evidence that graft-tunnel motion or the so-called bungee effect is unlikely to be the primary cause of radiographic bone tunnel enlargement following ACL reconstruction.

Anterior Cruciate Ligament↗

PubMed2005

Assessment of lower limb neuromuscular control in prepubescent athletes.

BACKGROUND: Although neuromuscular indices have been extensively studied in adolescents and adults, limited data exist for prepubescent children. HYPOTHESIS: No differences exist between prepubescent boys and girls in lower limb strength, symmetry on single-legged hop testing, and limb alignment during drop-jump testing. STUDY DESIGN: Cross-sectional study (prevalence); Level of evidence, 1. METHODS: The authors tested 27 female and 25 male athletes who were aged 9 to 10 years and matched for both body mass index and years of organized sports participation. In a drop-jump screening test, the distance between the right and left hips, knees, and ankles was measured as an indicator of lower limb axial alignment in the coronal plane. The distance between the knees and ankles was normalized by the hip separation distance. Quadriceps and hamstrings strengths were measured isokinetically at 180 deg/s. Lower limb symmetry was determined from 2 single-legged hop function tests. RESULTS: Boys demonstrated greater mean absolute and normalized knee and ankle separation distances on the drop-jump test. Even so, 76% of boys had a normalized knee separation distance of 60% or less of the hip separation distance, as did 93% of girls, indicating a distinctly valgus alignment. There were no differences between the sexes in quadriceps and hamstrings peak torques, hamstrings/quadriceps ratio, time to peak torque, total work, or lower limb symmetry values. CONCLUSIONS: A high percentage of the prepubescent athletes studied had a distinctly valgus lower limb alignment during the drop-jump test and a lack of lower limb symmetry during the hop tests. These same indices have been hypothesized to increase the risk for knee ligament injuries in older athletes. Neuromuscular training may be needed to address these issues in children.

Biomechanical Phenomena↗

PubMed2004

Distal hamstring lengthening in ambulatory children with cerebral palsy: primary versus revision procedures.

To document the benefits and limitations of distal hamstring lengthening (HL), 61 children (105 limbs) with cerebral palsy treated by distal HL with complete preoperative and postoperative evaluations were reviewed. There was significant improvement in popliteal angle, fixed knee flexion contracture, knee angle at foot contact (FC), and mid-stance knee extension after HL. On the other hand, the hip power generation peak decreased, and the anterior pelvic tilt increased. For the repeated HL (22 limbs), the fixed knee flexion contracture and knee flexion at FC improved. In a group of ten patients (17 limbs) with further postoperative follow up evaluations, the only significant clinical finding related to hamstring function between the first postoperative and the follow up evaluations with no intervening surgery was an increase in the popliteal angle of 20 degrees. Because the popliteal angle may increase over time after HL with no other directly related gait changes, the indications for repeated HL should include fixed knee flexion contracture and increased knee flexion at FC. The increase in the popliteal angle alone should not be considered an indication for repeated HL.

Cerebral Palsy↗

PubMed1985

Postural adjustments for jumping reaction movement in mentally retarded children: findings from EMG patterns.

EMG patterns during a jumping reaction task were studied in 53 mentally retarded children. EMGs were recorded from the knee extensors (VM and RF) and the knee flexors (hamstrings). Lack of synchronization between onset of phasic discharge in the VM and the RF and between onset in the hamstrings and the knee extensors was characteristic of retarded children. Deviation from the EMG pattern of normal adults decreased with increasing MA. The premotor time tended to be prolonged with increasing time differences between the VM and the RF responses. Shorter RT between the VM and the RF was consistent across EMG patterns. These were more apparent in subjects with MAs above 7 than in those with MAs below 6. It is suggested that the asynchronized EMG pattern reflects postural requirements due to poor formation of preparatory set.

Adolescent↗

PubMed1983

Characteristics of national, divisional, and club male alpine ski racers.

Forty-two Canadian male alpine ski racers of either club, divisional, or national team status were studied by group to evaluate the physiological parameters that distinguish these athletes. Measurements of physical characteristics, flexibility, muscular power and endurance, aerobic and anaerobic power, and isokinetic leg strength were made. Correlations of the test variables were performed to evaluate the test battery for validity. While there were few physiological differences between the national and divisional skiers, club skiers scored consistently lower (P less than 0.01) in maximum number of sit-ups, vertical jump, anaerobic endurance, muscular power, 2-mile run time, isokinetic leg strength at 30 degrees X s-1, and hamstring-to-quadriceps strength ratio. However, no significant differences between groups were observed in sum of the skinfolds, flexibility, and isokinetic strength at 180 degrees X s-1. There were also no differences in VO2max between club and national team skiers. Highly-significant correlations were found between selected test variables, which indicated that some of the physiological parameters shared common variance. It seems that many of these physiological tests do not discriminate between national and divisional skiers. Club skiers would, however, appear to benefit from training programs designed to develop leg strength, power, and anaerobic endurance.

Humans↗

PubMed1990

The relationship between peak torque and work of the quadriceps and hamstrings after knee injury.

The purpose of the present study was to assess the relationship between the isometric and isokinetic peak torques (speed of movement 0, 60, 180 deg/sec) and the total work output of multiple contractions (180 deg/sec) of the quadriceps and hamstrings in 68 patients having seven years earlier a hemarthrotic knee injury. At every test speed the Pearson product moment (r) and the Spearman rank (rs) correlation coefficients between the peak torque and the total work were highly significant (p less than 0.001) for the quadriceps and hamstrings in the uninjured (r = 0.74-0.92, rs = 0.75-0.93) as well as in the injured (r = 0.83-0.93, rs = 0.84-0.92) knees. All correlation coefficients were higher at the highest speed (180 deg/sec) of the isokinetic test (r = 0.90-0.93, rs = 0.91-0.93) than at the other speeds (0 and 60 deg/sec) (r = 0.74-0.88, rs = 0.75-0.89) obviously since the total work was registered at that speed. In conclusion, in injured or healthy knees the isokinetic total work analysis offers little additional information to that attained by more simple measurements, the peak torque recordings.

Adolescent↗

PubMed1996

The weight-bearing knee after anterior cruciate ligament rupture. An in vitro biomechanical study.

Unilateral weight bearing was simulated on 12 cadaver knees to quantitate anterior tibial translation (ATT) after anterior cruciate ligament (ACL) transection and to asses the role of the posteromedial structure and the hamstrings in controlling laxity. With the ACL intact, ATT was 3.5 +/- 2.8 mm in extension and 4.3 +/- 3.6 mm at 60 degrees flexion. After sectioning the ACL, ATT was 6.5 +/- 4.7 mm in extension and 17.5 +/- 10 mm at 60 degrees flexion (P = 0.001). Applying a force in the hamstrings was unable to correct the pathological ATT observed after ACL section. Partial medial meniscectomy did not increase ATT after the ACL section. Disinsertion of the posterior horn of the medial meniscus and total medial meniscectomy increased ATT significantly compared to isolated ACL section. After ACL transection, sectioning the meniscotibial fibers or posteromedial capsule significantly increased ATT (6.5 +/- 0.5 mm in extension). Section of the postero-oblique ligament or popliteus tendon had no effect on ATT.

Aged↗

PubMed2002

The anesthetic management of a patient with Emery-Dreifuss muscular dystrophy for orthopedic surgery.

PURPOSE: To report a patient with Emery-Dreifuss muscular dystrophy (EDMD) coming for an orthopedic procedure, with potential problems of sudden cardiac death, difficult airway, and neuromuscular disorders who was managed successfully by permanent pacemaker insertion, total iv anesthesia (TIVA), laryngeal mask insertion (LMA) insertion and continuous epidural blockade. CLINICAL FEATURES: A 22-yr-old man with known EDMD presented for triple arthrodesis of his right foot and fractional lengthening of his hamstrings bilaterally. Anesthesia was induced with a TIVA technique, and maintained throughout the operative period. A suspected difficult airway was managed by the use of a LMA, and analgesia for the peri-, and postoperative period provided by a continuous epidural infusion. The patient's perioperative course was uneventful. CONCLUSION: EDMD is a rare disorder. However, anesthesia is often required for orthopedic procedures. This case report illustrates the many potential difficulties that may be encountered. Regional anesthesia combined with light general anesthesia offers a method of avoiding many of these difficulties.

Adult↗

PubMed2002

What does the Ashworth scale really measure and are instrumented measures more valid and precise?

This study aimed to explore the limitations of the Ashworth scale for measuring spasticity. An isokinetic dynamometer to quantify resistance to passive stretch and surface EMG was used to verify if a stretch response occurred and, if so, at what joint angle. The authors sought to determine which components of passive resistance (magnitude, rate of change, onset angle of stretch, or velocity dependence) were most related to Ashworth scores and which were related to motor function in cerebral palsy (CP). Twenty-two individuals with spastic CP (11 males, 11 females; mean age 11.9 years, SD 4.3) and a comparison group of nine children without CP (four males, five females; mean age 11.3 years, SD 2.5) participated in the study. The group with CP included those with a diagnosis of spastic diplegia, hemiplegia, or quadriplegia, distributed across Gross Motor Functional Classification Levels. Procedures included: (1) clinical assessment at the knee joint, (2) functional assessments, and (3) isokinetic assessment of passive resistance torque in hamstrings and quadriceps at three velocities. EMG data were recorded simultaneously to identify stretch responses. Detecting stretch responses using the Ashworth scale compared with instrumented measures showed near complete agreement at extremes of the scale, with marked inconsistencies in mid-range values. Ashworth scores were correlated with instrumented measures, particularly for the quadriceps, with higher correlations to the rate of change in resistance (stiffness) and onset angle of stretch than to peak resistance torque. Those with greater resistance tended to have poorer function with isokinetic relations typically stronger.

Cerebral Palsy↗

PubMed2000

Sensorimotor changes after anterior cruciate ligament reconstruction.

The restoration of joint stability is unlikely to be dependent on passive properties of the joint alone, yet the effect of anterior cruciate ligament reconstructive surgery on the sensorimotor system largely remains unexplored. This study evaluated whether surgical reconstruction of the ligament had any effect on one indicator of sensorimotor function, hamstring contraction latency, which previously has been shown to be related to function. Twenty-five patients with unilateral chronic anterior cruciate ligament deficiency had measures of hamstring contraction latency obtained before and after (3 and 6 months) reconstruction. After surgery, the contraction latency difference was found to improve significantly (decrease) in patients who had a preexisting deficit. The mechanism for alteration in response time remains unclear, but an observed relationship between contraction latency and tibial translation supports a mechanical basis for the findings. It was concluded the sensorimotor changes associated with surgical reconstruction of the cruciate ligament may help to restore joint stability. The study highlights the need to appreciate sensorimotor consequences of cruciate ligament surgery.

Adult↗

PubMed1987

Rectus femoris transfer to improve knee function of children with cerebral palsy.

Stance phase stability and swing phase clearance, prerequisites for normal ambulation, often are lost in the gait of children with cerebral palsy. Lengthening of the hamstrings usually will improve stance-phase knee extension but will not greatly alter swing-phase knee flexion. This paper presents the outcome of transfer of the distal end of the rectus femoris in conjunction with hamstrings lengthening in 37 knees, and compares it with a control group of 24 knees in which only hamstrings lengthening was done. In the first group swing-phase knee flexion was improved by 16.0 +/- 14.4 degrees, compared to 9.5 +/- 7.5 degrees in the control group, and residual knee flexion in stance was reduced to 8.9 +/- 8.1 degrees, compared to 15.1 +/- 13.8 degrees in the controls. Poor outcome in the transfer-plus-lengthening group was associated mainly with foot rotation in excess of 8 degrees internally or externally, or postoperative knee flexion in stance. Criteria for selection of cases and methods of improving surgical outcome are discussed.

Adolescent↗

PubMed2000

Gait and electromyographic analysis of patients recovering after limb-saving surgery.

OBJECTIVE: Control of gait after limb-saving surgery.Design. Case series study. BACKGROUND: At the moment little is known about adaptations in patients' gait after limb-saving surgery. METHODS: Nineteen patients who underwent limb-saving surgery at least 1 yr earlier and 10 normal subjects were studied during treadmill walking. The main outcome measures were walking speed, step parameters and angular displacement of both legs and EMG of the biceps femoris, rectus femoris and medial gastrocnemius in the affected leg. RESULTS: Preferred walking speed in the patients was lower than in the controls (0.7 versus 1.1 m/s). Furthermore, stance phase of the non-affected leg was lengthened. All patients showed reduced stance phase knee flexion in the affected leg, while during the swing phase no difference was seen. The EMG signals of the rectus femoris and biceps femoris show changes, which are related to the location of surgery. CONCLUSIONS: The results showed that the gait pattern of the patients differed compared to normal gait. The reduced stance phase knee flexion in the hip group is based on a high degree of co-contraction between quadriceps and hamstring activity, while in the knee group this is based on the quadriceps avoidance pattern. The finding that there is still side-to-side asymmetry indicates that there is no complete reorganisation following the massive loss of input and output of the leg. It is possible that some reprogramming of the locomotor process occur. RELEVANCE: Gait and electromyographic analysis are essential for the quantitative assessments of the functional outcome in this type of surgery.

Adult↗

PubMed2001

Neurophysiologic influences on hamstring flexibility: a pilot study.

OBJECTIVE: To examine the potential contribution of neurologic influences on hamstring length during passive range of motion. DESIGN: Prospective study. SETTINGS: Academic sports medicine center. PATIENTS: 15 subjects undergoing arthroscopic surgery for unilateral knee injuries without previous injury to the contralateral knee. INTERVENTIONS: Subjects received: 1) spinal anesthesia with bupivacaine, 2) epidural anesthesia with lidocaine, 3) general anesthesia, or 4) femoral nerve block of injured leg only. MAIN OUTCOME MEASURES: Noninjured leg popliteal angle preoperatively, intraoperatively under anesthesia, and postoperatively after recovery from anesthesia. RESULTS: The overall mean popliteal angle was 132.5 +/- 3.1 degrees preoperatively, 134.31 +/- 11.6 degrees intraoperatively, and 130.7 +/- 10.2 degrees postoperatively. Overall, the intraoperative angle was significantly greater than the postoperative angle (p = 0.02). The mean change in popliteal angle was 8.1 +/- 2.2 degrees (Group 1), -0.4 +/- 1.9 degrees (Group 2), 0.9 +/- 1.4 degrees (Group 3), and -2.4 +/- 3.8 degrees (Group 4). There was no significant change in pre- to postoperative popliteal angle in relation to postoperative pain. Females had a greater mean popliteal angle (139.84 degrees ) compared with males (128.84 degrees ) (p = 0.04). CLINICAL RELEVANCE: Understanding the neuromuscular influences on muscle flexibility will assist in the development of new rehabilitative and injury preventative techniques. CONCLUSION: The present pilot study implicates neural contributions to muscle flexibility. Further studies are needed to delineate the relative contributions of neural and muscular components and to facilitate new techniques in the rehabilitation and prevention of injury.

Adolescent↗

PubMed1993

Gating of transmission to motoneurones by stimuli applied in the locus coeruleus and raphe nuclei of the cat.

1. Neuronal systems activated by stimulation in the region of the locus coeruleus/subcoeruleus (LC/SC) and raphe nuclei have previously been shown to depress transmission from group II muscle afferents in regions of the midlumbar spinal segments in which premotor interneurones are located. The aim of the present investigation was to determine the extent to which such depression is paralleled by depression of the reflex actions of group II afferents on motoneurones. 2. The effects of short trains of conditioning electrical stimuli applied within the LC/SC and raphe nuclei were examined on postsynaptic potentials (PSPs) evoked by group I and group II muscle afferents in hindlimb motoneurones. The effects were examined over a wide range of conditioning-test intervals but particular emphasis was placed on the effects produced at long intervals (> 100 ms) since such effects are more likely to be mediated by the descending noradrenergic and serotonergic neurones of the LC/SC and raphe nuclei which are of slow conduction velocity. In addition, conditioning stimuli alone evoked PSPs in motoneurones (with latencies of 7-15 ms and a duration of 50-80 ms) and effects evoked at short conditioning-test intervals might therefore have been secondary to changes in motoneurone membrane properties. 3. At conditioning-test intervals between 100 and 350 ms synaptic actions of group II origin were strongly and consistently depressed. Both EPSPs and IPSPs were affected, two-thirds of those tested being reduced in amplitude by 50% or more. A similar depression was exerted on PSPs evoked from the quadriceps and deep peroneal nerves mediated predominantly by interneurones located in the midlumbar segments and on PSPs evoked from the hamstring and triceps surae nerves mediated by interneurones located in more caudal segments. It is thus concluded that neuronal systems activated by stimuli applied in the LC/SC and raphe nuclei are capable of gating transmission in all those interneuronal pathways which mediate the reflex actions of group II afferents on motoneurones in anaesthetized animals.

Animals↗

PubMed2006

Smoking and reconstruction of the anterior cruciate ligament.

We sought to determine whether smoking affected the outcome of reconstruction of the anterior cruciate ligament. We analysed the results of 66 smokers (group 1 with a mean follow-up of 5.67 years (1.1 to 12.7)) and 238 non-smokers (group 2 with a mean follow-up of 6.61 years (1.2 to 11.5)), who were statistically similar in age, gender, graft type, fixation and associated meniscal and chondral pathology. The assessment was performed using the International Knee Documentation Committee form and serial cruciometer readings. Poor outcomes were reported in group 1 for the mean subjective International Knee Documentation Committee score (p < 0.001), the frequency (p = 0.005) and intensity (p = 0.005) of pain, a side-to-side difference in knee laxity (p = 0.001) and the use of a four-strand hamstring graft (p = 0.015). Patients in group 1 were also less likely to return to their original level of pre-injury sport (p = 0.003) and had an overall worse final 7 International Knee Documentation Committee grade score (p = 0.007). Despite the well-known negative effects of smoking on tissue healing, the association with an inferior outcome after reconstruction of the anterior cruciate ligament has not previously been described and should be included in the pre-operative counselling of patients undergoing the procedure.

Adolescent↗

PubMed1991

[Muscular isokinetic dynamometry].

In the past, muscular strength has primarily been measured using isometric, isotonic or tensiometric techniques. The advent of isokinetic dynamometers has supplied an objective method of measuring peak torque throughout a full range of motion at a predetermined speed of contraction. An isokinetic contraction is a refinement of the controlled motion concept. The isokinetic contraction is dynamic, but the speed of the motion is held constant by a special device. In this way, resistance is in direct ratio to the varying force applied through the full course of a natural movement. The purpose of this study was to determine the peak torque of quadriceps (Q), and hamstrings (H), and their biomechanical angle of production, H to Q ratio and bilateral comparisons of these variables for the first time in a Southamerican population. Twenty healthy and voluntary males (age: 21.9 +/- 3.1 years, height 193.2 +/- 6.5 cm, weight: 84.2 +/- 5.2 kgs.), were tested on the Cybex II Dynamometer and Cybex Data Reduction Computer (CDRC). Quadriceps and hamstrings peak torque (pkTQ), in Newton-meters, were obtained at angular velocities of 60, 180 and 240 degrees. sec-1. Also, the angle of the range of motion at which peak torque occurred in both directions, H and Q peak torque to body weight ratios, H to Q ratio were measured. Finally, CDRC provided the bilateral comparison of the different variables expressed in percentages. All measurements were automatically corrected for the effect of gravity. The absolute maximal pkTQ of dominant (D), and non-dominant (ND), quadriceps at 60 degrees/sec was DQ 297 +/- 25 Nwm and nDQ 303 +/- 13 Nwm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

Rectus and hamstring surgery in cerebral palsy: a gait analysis study of results by functional ambulation level.

The purpose of this study is to determine if children more severely involved with cerebral palsy respond as well to rectus transfer and hamstring surgery as those with less severe involvement. Ninety-nine children were classified as independent community ambulators, crutch/walker-dependent community ambulators, or household/exercise ambulators. Maximum knee extension in stance and total range of knee motion in gait increased following surgery in all groups. Peak knee flexion in swing was maintained in the independent group only, but timing of knee flexion in swing improved in all groups. All groups showed increases in stride length, and the household/exercise group also showed an increase in walking speed. Four of 39 crutch/walker-dependent community ambulators and 13 of 21 household/exercise ambulators progressed to the next higher functional ambulation group.

Adolescent↗