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Restraint use and lower extremity fractures in frontal motor vehicle collisions.

BACKGROUND: Seat belts and air bags have been shown to significantly reduce morbidity and mortality following MVCs. Research suggests that restraint use does not protect against lower extremity fracture; however, no population-based studies of this association exist. The purpose of this study is to compare the effectiveness of combined seat belt and airbag restraint systems with airbag alone, seat belt alone, and no restraints with respect to incidence and location of lower extremity fractures. METHODS: A retrospective analysis of front seat occupants involved in police-reported, tow-away frontal MVCs was conducted using data from the 1995 through 2000 National Automotive Sampling System (NASS). Incidence and relative risk (RR) of fracture to specific bony regions were measured according to seat belt use and airbag deployment. RESULTS: Compared with unrestrained occupants, occupants restrained with airbag only had significantly higher risk for all types of lower extremity fractures whereas those occupants restrained with either seat belt only or seat belt and airbag had lower risk of fracture. The greatest difference was seen with tibia/fibula fractures in airbag only (RR, 2.14) but this trend continued to be significant with femur and pelvic fractures (RR, 1.13 and 1.23, respectively). CONCLUSION: While airbags may reduce the risk of death when used alone or in combination with seat belts, the results of this study demonstrate that air bags increase the risk of lower extremity fractures when used as the sole method of passenger protection. Also, they may do so differentially according to skeletal region. This data strongly support the consideration of developing accessory knee bolster airbags to prevent the "submarining" or sliding under the airbag that may be responsible for this finding.

Accident Prevention↗

Adenovirus-mediated gene transfer of VEGF(121) improves lower-extremity endothelial function and flow reserve.

BACKGROUND: Vascular endothelial growth factor (VEGF) currently is being evaluated in clinical angiogenesis trials involving patients with peripheral arterial disease. We hypothesized that delivery of VEGF to the skeletal muscle of the lower extremity using an adenoviral vector (Ad(GV)VEGF(121.10)) would improve peripheral endothelial function. Accordingly, we investigated lower-extremity endothelial function in patients enrolled in a Phase I adenovirus-mediated gene delivery trial of VEGF(121.10). METHODS AND RESULTS: Blood flow to the index extremity was measured by thermodilution at baseline and 30 days after administration of Ad(GV)VEGF(121.10), in response to the infusion of endothelium-dependent and -independent agonists (acetylcholine and nitroglycerin, respectively) into the ipsilateral femoral artery. There was no difference in basal flow before or after treatment with Ad(GV)VEGF(121.10). In response to acetylcholine (150 microg/min and 300 microg/min), there was a 0.9-fold (0.33+/-0.03 to 0.32+/-0.03 L/min) and 1.2-fold (0.33+/-0.03 to 0.490+/-0.02 L/min) change in flow before Ad(GV)VEGF(121.10) treatment. After Ad(GV)VEGF(121.10) treatment, flow increased 2.4-fold (0.310+/-0.04 to 0.730+/-0.10 L/min) and 2.3-fold (0.31+/-0.04 to 0.7+/-0.08 L/min), respectively (P<0.05 before Ad(GV)VEGF(121.10) treatment versus after Ad(GV)VEGF(121.10) for both doses). Infusion of nitroglycerin resulted in a 1.8-fold increase in flow before Ad(GV)VEGF(121.10) (0.33+/-0.03 to 0.58+/-0.06 L/min) compared with a 2.4-fold increase (0.31+/-0.04 to 0.73+/-0.09 L/min) after Ad(GV)VEGF(121.10) (P=NS before Ad(GV)VEGF(121.10) versus after Ad(GV)VEGF(121.10)). Lower-extremity flow reserve increased in all patients in response to at least 1 dose of acetylcholine. Peak walking times increased concomitant with improvement in endothelial function. CONCLUSIONS: Adenoviral gene transfer of VEGF(121.10) appears to modulate endothelial function and lower-extremity flow reserve in patients with peripheral arterial disease.

Acetylcholine↗

An analysis of the effect of lower extremity strength on impact severity during a backward fall.

At least 280 000 hip fractures occur annually in the U.S. at an estimated cost of $9 billion. While over 90 percent of these are caused by falls, only about 2 percent of all falls result in hip fracture. Evidence suggests that the most important determinants of hip fracture risk during a fall are the body's impact velocity and configuration. Accordingly, protective responses for reducing impact velocity and the likelihood for direct impact to the hip, strongly influence fracture risk. One method for reducing the body's impact velocity and kinetic energy during a fall is to absorb energy in the lower extremity muscles during descent, as occurs during sitting and squatting. In the present study, we employed a series of in verted pendulum models to determine: (a) the theoretical effect of this mechanism on impact severity during a backward fall, and (b) the effect on impact severity of age-related declines (or exercise-induced enhancements) in lower extremity strength. Compared to the case of a fall with zero energy absorption in the lower extremity joints, best-case falls (which involved 81 percent activation of ankle and hip muscles, but only 23 percent activation of knees muscles) involved 79 percent attenuation (from 352 J to 74 J) in the body's vertical kinetic energy at impact (KEv), and 48 percent attenuation (from 3.22 to 1.68 m/s) in the downward velocity of the pelvis at impact (v(v)). Among the mechanisms responsible for this were: (1) eccentric contraction of lower extremity muscles during descent, which resulted in up to 150 J of energy absorption; (2) impact with the trunk in an upright configuration, which reduced the change in potential energy associated with the fall by 100 J; and (3) knee extension during the final stage of descent, which "transferred" up to 90 J of impact energy into horizontal (as opposed to vertical) kinetic energy. Declines in joint strength reduced the effectiveness of mechanisms (1) and (3), and thereby increased impact severity However, even with reductions of 80 percent in available torques, KEv was attenuated by 50 percent. This indicates the importance of both technique and strength in reducing impact severity. These results provide motivation for attempts to reduce elderly individuals' risk for fall-related injury through the combination of instruction in safe falling techniques and exercises that enhance lower extremity strength.

Accidental Falls↗

Validity of lower extremity strength and power utilizing a new closed chain dynamometer.

PURPOSE: The purpose of this study was to compare selected variables measured on a traditional isokinetic dynamometer (Cybex II) with a new lower extremity, closed chain dynamometer (Omnikinetic, OmK). METHODS: Twelve subjects (6 male, 6 female, age = 28+/-5 yr, mean +/- SD) performed Cybex II knee flexion and extension at 1.05, 3.14, and 5.23 rad x s(-1). A maximal effort of 10 repetitions of lower extremity concentric extension and eccentric flexion at 36% of subject's 1-RM was performed on the OmK. Crank power and joint (ankle, knee, and hip) kinetics were recorded as a mean of 10 repetitions. RESULTS: t-Tests revealed right versus left leg differences (P < 0.05) for Cybex II peak torque flexion at 5.23 rad x s(-1), and OmK knee and hip peak power and hip root mean square power (RMS) power. Cybex peak knee torques were related (Pearson r values 0.78-0.92, P < 0.01) to OmK peak knee torques. Cybex average power was related to OmK knee power (Pearson r values 0.71-0.96, P < 0.01) and OmK crank power (r = 0.62-0.94, P < .01). Correlations tended to be stronger comparing the OmK with the fastest (5.23 rad x s(-1)) Cybex II speed. CONCLUSIONS: These results suggest that the OmK knee and crank kinetic data are comparable to Cybex It isokinetic dynamometry. The ability to evaluate lower extremity joint exercise at a subject's maximal movement speed, in addition to the use of a closed-chain, multi-joint motion, may allow for the OmK to provide a more global evaluation of lower extremity kinetics during seated concentric-extension, eccentric-flexion exercise.

Adult↗

Reconstruction for lower extremity limb salvage in soft tissue carcinoma.

Limb salvage procedures for the lower extremity have a 95% success rate and have essentially supplanted primary amputation as the primary treatment for limb-threatening malignancies. En bloc tumor resection involving major neural and vascular structures that once led to amputation are now successfully reconstructed using free-tissue transfer in combination with neoadjuvant and adjuvant chemoradiation therapies and brachytherapy. Planning for reconstruction of complex lower extremity wounds begins at the time of diagnosis and extends to postoperative rehabilitation. Developing a successful reconstructive plan requires a team approach with accurate assessment of the anticipated loss of critical structures, wound location, defect size, and an understanding of the local and distant tissues available for reconstruction. Comprehensive assessment of the anticipated wound combined with an understanding of the distant and local tissues available for reconstruction allows the reconstructive surgeon to select tissues from the entire body that have improved functional and aesthetic outcomes for patients.

Combined Modality Therapy↗

Lower extremity reconstruction.

The current recommendation for surgical treatment of tumors of the lower extremity is a limb-sparing resection. Limb-sparing resection coupled with complex reconstructive techniques and complemented by new chemotherapeutic agents and adjuvant radiation therapy has allowed us to achieve survival rates that are comparable to those of amputation with a better functional outcome. Recent advances in microsurgical techniques and the associated technologies and a better understanding of microvascular anatomy has allowed us to customize flaps to the specific needs of the patients and to achieve a lower donor site morbidity. Increased communication between the specialties of the multidisciplinary treatment team has also improved outcomes. The reconstructive component has become an integral part of the multidisciplinary care for patients with lower extremity tumors. It not only allows them to rapidly resume adjuvant therapies but also enables them to more easily resume their activities of daily living.

Adult↗

Clinically suspected pulmonary embolism: use of bilateral lower extremity US as the initial examination--a prospective study.

PURPOSE: To determine the prevalence of deep venous thrombosis (DVT) and evaluate the use of symptoms and risk factors as selection criteria in the patient population undergoing lower extremity ultrasonography (US) as an initial examination for suspected pulmonary embolism (PE). MATERIALS AND METHODS: One hundred eighty-two consecutive patients referred for bilateral lower extremity US as the first examination for suspected PE were evaluated prospectively for predisposing factors and symptoms of DVT. Patients were placed into four groups: group 1, no symptoms or risk factors; group 2, both symptoms and risk factors; group 3, only risk factors; group 4, only symptoms. The prevalence of DVT detected at lower extremity US in each group was determined. RESULTS: There were 89 patients in group 1, 12 in group 2, 43 in group 3, and 38 in group 4, with a DVT prevalence of 0%, 25%, 14%, and 24%, respectively. There was no significant difference in DVT prevalence between groups with symptoms or risk factors but a significant difference between these groups and the group lacking both symptoms and risk factors. CONCLUSION: Lower extremity US as the initial examination in patients suspected of having PE should be used only in those patients who have symptoms or risk factors for DVT. This would substantially decrease the number of examinations performed without a decline in DVT detection.

Adolescent↗

Acute arterial thrombosis of the lower extremities due to prolonged intestinal obstruction.

A case of a female patient who was admitted urgently with intestinal obstruction, peripheral shock, hypovolemia and acute ischemia of the lower extremities is presented. The ischemia of the lower extremities had developed due to low cardiac output following extensive dehydration caused by a prolonged intestinal obstruction from a cholelith. Although this pathogenetic mechanism of acute ischemia of the lower extremities is well known, this characteristic case is, nevertheless, presented to alert the clinician of this situation.

Acute Disease↗

The lower-extremity musculature in chronic symptomatic instability of the anterior cruciate ligament.

We studied the musculature of the lower extremity in forty-one patients with chronic symptomatic instability of the anterior cruciate ligament. Computed tomographic and clinical measurements of the limb were taken at levels fifteen and twenty-five centimeters proximal to the medial joint line and ten centimeters distal to it. Biopsy specimens from the vastus lateralis of both lower extremities were analyzed by histochemistry and electron microscopy. Computed tomography revealed a decrease in the muscle square area of the affected thigh of 8 per cent as compared with the control lower extremity. There was quadriceps atrophy of 10 per cent and hamstrings atrophy of only 4 per cent. The atrophy of the vastus medialis was significantly greater than that of the entire quadriceps. Histochemistry revealed a similar decrease in fiber size for all fiber types, and hence no shift in fiber type. Electron microscopy showed an increase in intracellular fat but no change in mitochondrial volume density or capillarization.

Adolescent↗

Prenatal sonographic findings of massive lower extremity lymphangioma.

A massive lymphangioma was detected sonographically in the lower extremity of a fetus at 28 weeks' gestation. On ultrasound study, the mass had multiple cysts and extended from the left lower abdomen to the left knee. The differential diagnosis and obstetric management following prenatal diagnosis of a fetal lower extremity mass are presented.

Adult↗

The anterolateral thigh flap is highly effective for reconstruction of complex lower extremity trauma.

BACKGROUND: Trauma patients with high-energy injuries often present with severe tissue damage that extends beyond the immediate zone of injury and requires recruitment of vascularized tissues from distant sites. The objective of this study was to evaluate the utility of the anterolateral thigh (ALT) flap for reconstruction of the traumatically injured lower extremity. METHODS: Prospective data were collected on all patients who underwent lower extremity reconstruction with an ALT flap during a 3.5-year period at a primary adult resource center (PARC). Demographics captured included age, gender, Injury Severity Score, mechanism of injury, and size of defect and complications. RESULTS: Fifty-six patients underwent a total of 59 ALT flap harvests during the study period. The majority of patients were male (75%) and sustained blunt injury (95%). The mean age was 37 +/- 14 years with a mean Injury Severity Score of 17.9 +/- 8. The mean flap size was 20.7 x 8.4 cm, with 64% harvested from the injured limb. Total flap success rate was 91.5%, with four total (6.7%) and one partial flap failure (1.7%). CONCLUSION: The ALT flap is a useful tool for trauma reconstruction in lower extremity salvage. We have shown that the ALT flap can be performed successfully in the traumatically injured patient even when harvested from the ipsilateral lower extremity.

Adult↗

Venous and arterial anomalies of the lower extremities diagnosed by duplex scanning.

The complex embryologic development of the vascular system often results in a myriad of clinically relevant anomalies. It has been stated that the classic anatomic venous pattern in the lower extremity is found in only 16 percent of patients. Previous studies on this topic are limited to isolated venous dissections or phlebography that lack complete anatomic detail. The recent introduction of high resolution duplex scanners for the assessment of veins of the lower extremity provides a unique opportunity to determine the incidence of anatomic variation. The current prospective study was done to identify venous or arterial anomalies apparent during routine duplex scanning of the lower extremity performed to rule out deep venous thrombosis (DVT). Limbs that had evidence of acute or chronic extensive DVT were excluded. Of 1,600 consecutive extremity scans, 946 extremities (59 percent) had no evidence of DVT. Of these, there were 43 patients with 64 anomalies in 57 extremities. The mean age of the group was 53.4 years. There were 24 women (55.8 percent) and 19 men (44.2 percent). There were 59 (92.2 percent) venous and five (7.8 percent) arterial anomalies. Duplication of the superficial femoral vein was the most common anomaly noted. Duplication of the deep femoral and popliteal vein was also noted. Unilateral anomalies were more common than bilateral anomalies, namely 67.4 versus 32.6 percent, respectively. Pain and swelling, common complaints in the patients with an anomaly, were noted in 71.4 and 45.7 percent, respectively. The frequency of deep venous anomalies of the lower extremities may be less than previously reported. Knowledge concerning the incidence and distribution of venous anomalies may lead to improved assessment and treatment of venous disease.

Adult↗

Acute and long-term results after intra-arterial thrombolysis of occluded lower extremity bypass grafts using recombinant tissue plasminogen activator for acute limb-threatening ischemia.

Occlusion of lower extremity vascular bypass grafts results in acute limb-threatening ischemia. The underlying cause of graft failure generally is distal anastomosis stenosis, and relief of culprit stenosis is a required to maintain long-term patency. Of the three thrombolytic agents used for prolonged infusion to accomplish fibrinolysis, streptokinase was the first to be used and is limited owing to the antigenicity that precludes repeated use. Urokinase had been the mainstay of thrombolytic therapy until it was withdrawn by the U.S. Food and Drug Administration in 1999 because of the potential of transmission of infectious agents during its manufacturing process. Recombinant tissue plasminogen activator (rt-PA) has not been studied adequately to assess safety and efficacy, and there are no standardized dosing guidelines. We report our experience with six patients presenting with acute limb-threatening ischemia attributable to thrombosis of synthetic lower extremity bypass grafts. After thrombolysis using rt-PA (mean bolus dose, 12.2 +/- 3.6 mg; range, 6-15 mg administered over 5 minutes followed by infusion at 2 mg/h for 15.6 +/- 6.4 hours; total dose, 51 +/- 16 mg), successful thrombolysis was achieved in 84% of the patients. The primary patency rate was 75% and the secondary patency rate 100% at 16 weeks. One patient underwent amputation owing to unsuccessful thrombolysis. No major bleeding or vascular complications occurred. We conclude that intra-arterial thrombolysis using rt-PA is a safe and effective therapy for patients with thrombotic occlusion of synthetic lower extremity bypass grafts presenting with acute limb-threatening ischemia and allows a high rate of secondary patency, avoiding amputation.

Aged↗

Can the Perclose suture-mediated closure system be used safely in patients undergoing diagnostic and therapeutic angiography to treat chronic lower extremity ischemia?

PURPOSE: Mechanical closure devices for arterial hemostasis after angiography, such as the Perclose suture-mediated closure system, are designed to decrease time to ambulation and improve patient comfort. Although these devices are safe and efficacious, to date there has been little reported about use of the Perclose device in a cohort consisting exclusively of patients with lower extremity peripheral vascular disease. The purpose of this study was to determine the safety and efficacy of routine use of the Perclose system in patients with documented peripheral vascular disease undergoing angiography to treat chronic lower extremity ischemia. METHODS: The Perclose device was placed for arterial closure after femoral artery access in 500 consecutive patients with documented peripheral vascular disease (ankle-brachial index, <0.8) who underwent diagnostic angiography or percutaneous intervention because of chronic lower extremity ischemia. These 500 patients composed 91% of all patients who underwent angiography because of chronic lower extremity ischemia between January 1, 2001, and April 1, 2002. All complications associated with the Perclose device were identified and reviewed. RESULTS: Of the 500 arteries, 54% were accessed for diagnostic angiography and 46% for intervention. Perclose device placement was successful in 475 attempts (95%). Overall major complication rate was 1.4% (7 of 500 arteries). Complications included one death from retroperitoneal hemorrhage; three episodes of limb ischemia, two requiring operation and one requiring lytic therapy; two pseudoaneurysms; and one hematoma, which prolonged hospitalization. The hematoma was the only complication in the 25 patients with failed Perclose device placement. There were no infections requiring admission or operation. CONCLUSION: The Perclose suture-mediated closure device is efficacious and can be used safely in selected patients with documented peripheral vascular disease. Complications associated with this device tend to be more severe than those historically reported for manual compression. Substantial experience with use of this device is required to achieve excellent results in patients with difficult anatomy.

Angiography↗

Measuring activity limitations in walking: development of a hierarchical scale for patients with lower-extremity disorders who live at home.

OBJECTIVE: To develop a hierarchical scale that measures activity limitations in walking in patients with lower-extremity disorders who live at home. DESIGN: Cross-sectional study. SETTING: Orthopedic workshops and outpatient clinics of secondary and tertiary care centers. PARTICIPANTS: Patients (N=981; mean age +/- standard deviation, 58.6+/-15.4 y; 46% men) living at home, with different lower-extremity disorders: stroke, poliomyelitis, osteoarthritis, amputation, complex regional pain syndrome type I, and diabetic and degenerative foot disorders. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: (1) Fit of the monotone homogeneity model, indicating whether items can be used for measuring patients; (2) fit of the double monotonicity model, indicating invariant (hierarchical) item ordering; (3) intratest reliability, indicating repeatability of the sum score; (4) robustness, addressing the clinimetric properties within subgroups of patients; and (5) differential item functioning, addressing the validity of comparisons between subgroups of patients. RESULTS: Thirty-five of 41 dichotomous items had (1) good fit of the monotone homogeneity model (coefficient H=.50), (2) good fit of the double monotonicity model (coefficient H(T)=.33), (3) good intratest reliability (coefficient rho=.95), (4) satisfactory robustness (within subgroups of patients defined by age, sex, and diagnosis), and (5) some differential item functioning (6 items in amputees compared with nonamputees). CONCLUSIONS: A hierarchical scale, with excellent scaling characteristics, was developed to measure activity limitations in walking in patients with lower-extremity disorders who live at home. The measurements should be interpreted cautiously when making comparisons between amputees and nonamputees.

Cross-Sectional Studies↗

Measuring activity limitations in climbing stairs: development of a hierarchical scale for patients with lower-extremity disorders living at home.

OBJECTIVE: To develop a hierarchical scale that measures activity limitations in climbing stairs in patients with lower-extremity disorders living at home. DESIGN: Cross-sectional study with Mokken scale analysis of 15 dichotomous items. SETTING: Outpatient clinics of secondary and tertiary care centers. PARTICIPANTS: Patients (N=759; mean age +/- standard deviation, 59.8+/-15.0y; 48% men) living at home, with different lower-extremity disorders: stroke, poliomyelitis, osteoarthritis, amputation, complex regional pain syndrome type I, and diabetic foot problems. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: (1) Fit of the monotone homogeneity model, indicating whether items can be used for measuring patients; (2) fit of the double monotonicity model, indicating invariant (hierarchical) item ordering; (3) intratest reliability, indicating repeatability of the sum score; and (4) differential item functioning, addressing the validity of comparisons between subgroups of patients. RESULTS: There was (1) good fit of the monotone homogeneity model (coefficient H=.50) for all items for all patients, and for subgroups defined by age, gender, and diagnosis; (2) good fit of the double monotonicity model (coefficient H(T)=.58); (3) good intratest reliability (coefficient rho=.90); and (4) no differential item functioning with respect to age and gender, but differential item functioning for 4 items in amputees compared with nonamputees. CONCLUSIONS: A hierarchical scale, with excellent scaling characteristics, has been developed for measuring activity limitations in climbing stairs in patients with lower-extremity disorders who live at home. However, measurements should be interpreted with caution when comparisons are made between patients with and without amputation.

Activities of Daily Living↗

Deterioration of venous function in normal lower extremities during daily activity.

The change in venous function during the course of the day was studied noninvasively in 50 normal lower extremities of 25 physically active normal subjects. Venous refilling time, measured by photoplethysmography, was significantly shorter (p less than 0.0001), and venous capacitance, measured by impedance plethysmography, was significantly reduced (p less than 0.04) after 5 hours or more of daily activities performed in the upright position. Abnormally short venous refilling time (less than 18 seconds) developed in 21% of the extremities, which had a normal venous refilling time earlier in the same day. Lower extremity symptoms of ache, pain, or swelling were reported more frequently in extremities that developed an abnormal venous refilling time. There was a trend toward a greater change in venous refilling time during the day in symptomatic lower extremities than in asymptomatic limbs (p = 0.07).

Adult↗

Left, right, near or far wall common carotid intima-media thickness measurements: associations with cardiovascular disease and lower extremity arterial atherosclerosis.

We evaluated the differences in strength of the associations of prevalent cardiovascular disease and lower extremity arterial atherosclerosis to common carotid intima-media thickness, assessed by near wall measurements only, by far wall measurements only, and by the average of near and far wall measurements. The study was based on data from 1500 participants of the Rotterdam Study, a single-center-population-based prospective follow-up study among 7983 subjects, aged 55 years or over. Comparison of the strength of the associations of near wall intima-media thickness and of combined near and far wall intima-media thickness to cardiovascular disease and lower extremity arterial atherosclerosis revealed significantly stronger associations compared to associations observed for far wall intima-media thickness, in particular for stroke and lower extremity arterial disease. We conclude that near wall common carotid intima-media thickness measurement provides at least as good an indicator of atherosclerosis elsewhere and of cardiovascular risk as the far wall intima-media thickness measurement.

Arteriosclerosis↗