44,167 research outputs found
Longitudinal kinematic and kinetic adaptations to obstacle crossing in recent lower limb amputees
No full textBackground: Obstacle crossing is an important activity of daily living, necessary to avoid tripping or falling, although it is not fully understood how transtibial amputees adapt to performing this activity of daily living following discharge from rehabilitation.
Objectives: The objective of this study was to investigate the longitudinal adaptations in obstacle crossing in transtibial amputees post-discharge from rehabilitation.
Study design: Longitudinal repeated measures.
Methods: Seven unilateral transtibial amputees crossed an obstacle 0.1m high positioned along a walkway while kinematic and kinetic data were recorded at 1, 3 and 6 months post-discharge.
Results: At 6 months post-discharge, walking velocity had increased (0.17 m.s−1) with most participants self-selecting an intact lead limb preference. During swing phase, peak knee flexion (p = 0.03) and peak knee power absorption (K4; p = 0.01) were greater with an intact versus affected lead limb preference. Having crossed the obstacle, intact limb peak ankle power generation in pre-swing (A2; p = 0.01) and knee power absorption (K3; p = 0.05) during stance phase were greater when compared to the affected limb.
Conclusions: Obstacle crossing improved, although a greater reliance on intact limb function was highlighted. Results suggested that further improvements to locomotor performance may be obtained by increasing affected limb knee range of motion and concentric and eccentric strength of the knee extensors and flexors.
Clinical relevance The novel objective data from this study establish an understanding of how recent transtibial amputees adapt to performing obstacle crossing following discharge from rehabilitation. This allows for evidence-based clinical interventions to be developed, aimed at optimising biomechanical function, thus improving overall locomotor performance and perhaps subsequent quality of life
Coordination of limb bud development : the role of SHH in PD limb bud patterning
No full textThe limb bud serves as an excellent model to investigate the signals involved in diverse processes during embryonic development. Limb bud development is controlled by complex regulatory networks that instruct coordinated patterning and proliferation of mesenchymal progenitors along the dorso-ventral (DV), antero-posterior (AP) and proximo-distal (PD) limb axes. Over the last two decades many of the underlying molecular mechanisms instructing limb development have been described. Nevertheless, little is known about how these signals are integrated into the networks controlling limb bud development and how the cells respond to these signals to acquire their identity. Sonic hedgehog (SHH) is known to specify the AP limb bud axis and regulate its expansion as part of a larger self-regulatory signalling system. To analyze the genome-wide effects and to identify novel targets of SHH signalling in the limb bud, we have performed microarray analysis on Shh-deficient limb buds. From this analysis we have identified a novel kinase (Pkdcc), whose expression is up-regulated in Shh-deficient limb buds and that is dynamically expressed during development. Targeted deletion of the Pkdcc gene in mice shows that Pkdcc is essential for embryonic development. Furthermore, the transcriptome analysis uncovers an unexpected function of SHH in PD limb axis development as Shh-deficient mouse limb buds are proximalized. Expression of proximal genes and retinoic acid (RA) pathway activity are up-regulated and distally expanded in Shh-deficient limb buds. In parallel, the expression of the RA inactivating enzyme Cyp26b1 is decreased in the distal mesenchyme. We have investigated the possible SHH-RA interactions using a combination of experimental manipulation, genetics and mathematical simulations. Our findings reveal a SHH-dependent signalling module that normally enhances RA clearance by increasing fibroblast growth factor (FGF) signalling in the apical ectodermal ridge (AER), which in turn up-regulates Cyp26b1 expression in the distal mesenchyme. Disruption or reduction of CYP26b1-mediated RA clearance interferes with distal limb bud development leading to molecular proximalization of Shh-, AER-Fgf- and Cyp26b1-deficient limb buds. In addition, we provide molecular evidence for early specification of the PD axis by a mutually inhibitory interaction of RA with AER-FGFs. Subsequently AP and PD limb bud patterning becomes interlinked via SHH mediated regulation of the AER-FGF/CYP26b1/RA signalling module, which enables spatially coordinated progression of limb bud development
Major Limb Amputations: A Tertiary Hospital Experience in Northwestern Tanzania.
No full textMajor limb amputation is reported to be a major but preventable public health problem that is associated with profound economic, social and psychological effects on the patient and family especially in developing countries where the prosthetic services are poor. The purpose of this study was to outline the patterns, indications and short term complications of major limb amputations and to compare our experience with that of other published data. This was a descriptive cross-sectional study that was conducted at Bugando Medical Centre between March 2008 and February 2010. All patients who underwent major limb amputation were, after informed consent for the study, enrolled into the study. Data were collected using a pre-tested, coded questionnaire and analyzed using SPSS version 11.5 computer software. A total of 162 patients were entered into the study. Their ages ranged between 2-78 years (mean 28.30 ± 13.72 days). Males outnumbered females by a ratio of 2:1. The majority of patients (76.5%) had primary or no formal education. One hundred and twelve (69.1%) patients were unemployed. The most common indication for major limb amputation was diabetic foot complications in 41.9%, followed by trauma in 38.4% and vascular disease in 8.6% respectively. Lower limbs were involved in 86.4% of cases and upper limbs in 13.6% of cases giving a lower limb to upper limb ratio of 6.4:1 Below knee amputation was the most common procedure performed in 46.3%. There was no bilateral limb amputation. The most common additional procedures performed were wound debridement, secondary suture and skin grafting in 42.3%, 34.5% and 23.2% respectively. Two-stage operation was required in 45.4% of patients. Revision amputation rate was 29.6%. Post-operative complication rate was 33.3% and surgical site infection was the most common complication accounting for 21.0%. The mean length of hospital stay was 22.4 days and mortality rate was 16.7%. Complications of diabetic foot ulcers and trauma resulting from road traffic crashes were the most common indications for major limb amputation in our environment. The majority of these amputations are preventable by provision of health education, early presentation and appropriate management of the common indications
Interlinked signaling feedback loops and self-regulation during vertebrate limb development
No full textReliable organ and tissue morphogenesis seems to depend on self-regulatory mechanisms that are able to buffer spontaneous and/or genetic variations. While the analysis of the interactions of BMPs with their antagonists during gastrulation has provided insights into the self-regulatory capacity of early embryos, few other mechanisms endowing developmental programmes with robustness have been identified. Limb development and digit specification are regulated by epithelial-mesenchymal (e-m) interactions involving instructive SHH and FGF signaling. The BMP antagonist Gremlin1 (GREM1) is key to establishing these interactions. By combining genetics with ex vivo manipulation and mathematical modeling, we establish that both BMP4 and SHH positively regulate Grem1 expression, defining this antagonist as a critical node that links a fast and self-regulatory BMP4/GREM1 module to the SHH/GREM1/FGF e-m feedback loop. This network architecture allows a self-regulative switch from BMP4- to SHH-driven limb development and endows limb patterning with robustness against variations in gene activity due to interconnectivity between the BMP, SHH and FGF signaling pathways. The establishment of this robust signaling network may have contributed to the appearance and stabilization of pentadactyly in tetrapods
Temporal adaptations in generic and population-specific quality of life and falls efficacy in men with recent lower-limb amputations
No full textThis study examined the longitudinal changes in generic health-related quality of life (QOL), prosthesis-related QOL, falls efficacy, and walking speed in men with lower-limb amputations up to 6 months following discharge from rehabilitation. Seven male unilateral transtibial amputees completed the Medical Outcomes Study 36-Item Short Form Health Survey, the Prosthesis Evaluation Questionnaire, and the Modified Falls Efficacy Scale at 1, 3, and 6 months postdischarge from rehabilitation. Walking speed was also recorded to objectively assess participants– mobility. Health-related QOL measures displayed increases, resulting in large effect sizes though not reaching statistical significance. Prosthesis-related QOL measures indicated that scales relating to the participants– prostheses improved and the support of significant others was the most positively scored variable. Walking speed increased by 0.12 m/s, although it was not significantly related to indices of QOL or falls efficacy. Falls efficacy did not improve significantly during the study period, although it was strongly related to QOL (p < 0.05). These results provide a novel insight into how QOL and falls efficacy develop in people with lower-limb amputations, alongside changes in mobility, after discharge from rehabilitation. Further improvements in physical health following discharge may be required to elicit subsequent increases in overall QOL and concurrent improvements in falls efficacy
Upper Limb: Shoulder and Arm
No full textThis book provides a comprehensive compilation of musculoskeletal ultrasonography (MSUS) fundamentals in pediatric rheumatology with emphasis on imaging techniques, normal anatomy, approaches towards standardization, and the spectrum of pathologic findings seen in the pediatric population. It examines the techniques and pitfalls of MSUS in pediatrics and compares sonoanatomy in pediatric patients versus adults. Chapters cover a range of anatomical sites, including shoulder and arm, elbow and forearm, wrists and hands, hip and thigh, knee and leg, and ankle and feet. The text also discusses the use of ultrasonography in juvenile inflammatory arthritic conditions and sports-related injuries. Finally, the book concludes with a summary of the recent advances in pediatric musculoskeletal ultrasonography. Featuring contributions from a large international group of leaders in the field, Pediatric Musculoskeletal Ultrasonography is an authoritative reference for pediatric and adult rheumatologists, sonographers, radiologists, physiotherapists, and orthopedic specialists
Recovery of muscle strength and power after limb-lengthening surgery
No full textBarker KL, Lamb SE, Simpson HRW. Recovery or muscle strength and power after limb-lengthening surgery. Arch Phys Med Rehabil 2010;91:384-8.
Objective: To report muscle strength, power, and function after limb-lengthening surgery performed by using the Ilizarov technique.
Design: Prospective, longitudinal observational study of a cohort of consecutive patients who underwent limb-lengthening distraction followed up for 2 years after surgery.
Setting: National Health Service hospital specializing in orthopedic surgery.
Participants: Patients (N=16) who had undergone limb-lengthening surgery performed by using the Ilizarov method (11 men, 5 women; mean age=27y; range, 13-56y).
Interventions: None.
Main Outcome Measures: Muscle strength and power were assessed by using 2 validated measures: isokinetic concentric strength of the quadriceps and hamstrings measured by using a dynamometer and leg extensor power. Measures were recorded preoperatively and at 6, 12, and 24 months after the completion of lengthening. Function was measured by 2 timed tests of functional performance: stair climbing and sit-to-stand.
Results: Overall results were good with high reports of function and satisfactory clinical examination. Both concentric muscle strength and leg power showed a clear pattern of decreased muscle strength at 6 months after frame removal, improving throughout the study period until it was within 3% of the preoperative value at 2 years. By 2 years, self-reported function and ability to complete timed functional tests had returned to or improved on the preoperative values. Muscle strength remained slightly below the preoperative value; this was more pronounced in the quadriceps than the hamstrings. There was no association between muscle strength and the amount of lengthening that had been undertaken.
Conclusions: This study suggests that there is a small residual decrease in muscle strength and power after limb-lengthening surgery but that these do not adversely impact on a patients' ability to perform everyday functional activities
Dissociation of phantom limb phenomena from stump tactile spatial acuity and sensory thresholds
No full textMost amputees experience phantom limb sensations and/or phantom limb pain as well as residual limb (stump) pain that are resistant to treatment. Phantom phenomena are not homogeneous; each patient presents with a unique combination of spontaneous or evoked sensations, pain, and/or awareness. In an effort to understand the underlying mechanisms, postamputation pain has been subclassified based on the perceived sensory qualities reported by the individual. However, little is known about the relationship between subjective phantom phenomena and sensory function of the residual stump. The aim of the present study was to determine if sensory processing, as measured psychophysically, reflected subjective reports of specific qualities of phantom and/or stump sensory phenomena. Twelve individuals who had recently (within 6 months) undergone traumatic unilateral upper extremity amputation participated in the study. Limb temperature, thermal thresholds, tactile sensory thresholds and tactile spatial acuity were compared between the residual limb and the intact limb, and related to patient reports of specific stump and phantom sensory phenomena. All but one subject reported phantom sensations and/or phantom pain. The remaining subject reported only stump pain. Mean skin temperature of the residual limb was significantly lower than that of the intact contralateral limb by approximately 0.9°C in the proximal portion of the stump and 1.7°C at the stump tip. However, the temperature of the stump (compared with the intact limb) did not reflect subjective reports of stump or phantom limb thermal characteristics. Thermal threshold abnormalities differed among patients, and did not suggest any pattern of small fibre loss of function or generalized hyperexcitability. Other than within grafted tissue or near the scar area, skin areas that the patient described as abnormally sensitive or tender to touch were not accompanied by corresponding abnormalities in static tactile thresholds or tactile spatial acuity. Tactile spatial acuity was heightened near the scar area only. The proportion of subjects who had decreased two-point discrimination thresholds at the stump did not differ significantly according to the reporting or non-reporting of dual percepts. Thus, despite a common injury, the sensory abnormalities varied within this cohort of subjects. In addition, psychophysical threshold measures of sensory function did not reflect, in any simple way, subjective phantom phenomena. Therefore, classification of phantom phenomena based on peripheral sensory function may be a misleading step in the search for specific mechanisms underlying postamputation sensory phenomena
Indications to Vascularized Fibula Transplantation in Limb Salvage Surgery
No full textIndications to Vascularized Fibula Transplantation in Limb Salvage Surger
Rapid and repeated limb loss in a clade of scincid lizards
No full text© 2008 Skinner et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: The Australian scincid clade Lerista provides perhaps the best available model for studying limb reduction in squamates (lizards and snakes), comprising more than 75 species displaying a remarkable variety of digit configurations, from pentadactyl to entirely limbless conditions. We investigated the pattern and rate of limb reduction and loss in Lerista, employing a comprehensive phylogeny inferred from nucleotide sequences for a nuclear intron and six mitochondrial genes. Results: The inferred phylogeny reveals extraordinary evolutionary mutability of limb morphology in Lerista. Ancestral state reconstructions indicate at least ten independent reductions in the number of digits from a pentadactyl condition, with a further seven reductions proceeding independently from a tetradactyl condition derived from one of these reductions. Four independent losses of all digits are inferred, three from pentadactyl or tetradactyl conditions. These conclusions are not substantially affected by uncertainty in assumed rates of character state transition or the phylogeny. An estimated age of 13.4 million years for Lerista entails that limb reduction has occurred not only repeatedly, but also very rapidly. At the highest rate, complete loss of digits from a pentadactyl condition is estimated to have occurred within 3.6 million years. Conclusion: The exceptionally high frequency and rate of limb reduction inferred for Lerista emphasise the potential for rapid and substantial alteration of body form in squamates. An absence of compelling evidence for reversals of digit loss contrasts with a recent proposal that digits have been regained in some species of the gymnophthalmid clade Bachia, possibly reflecting an influence of differing environmental and genetic contexts on the evolution of limb morphology in these clades. Future study of the genetic, developmental, and ecological bases of limb reduction and loss in Lerista promises the elucidation of not only this phenomenon in squamates, but also the dramatic evolutionary transformations of body form that have produced the extraordinary diversity of multicellular organisms.Adam Skinner, Michael SY Lee and Mark N Hutchinso
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