Open reduction, ulnar osteotomy and external fixation for chronic anterior dislocation of the head of the radius.
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We reviewed 15 patients, nine girls and six boys, with chronic anterior dislocation of the radial head which was treated by ulnar osteotomy, external fixation and open reconstruction of the elbow joint but without repair of the annular ligament. Their mean age was 9.5 years (5 to 15) and the mean interval between the injury and reconstruction was 22 months (2 months to 7 years). All radial heads remained reduced at a mean follow-up of 20 months (6 months to 5 years). Normal ranges of movement for flexion, extension, pronation and supination were unchanged in 96.1% (49/51) and worse in 3.9% (2/51). Limited ranges of movement were improved in 77.8% (7/9), unchanged in 11% (1/9) and further decreased in 11% (1/9).There were two superficial pin-track infections and two cases of delayed union but with no serious complications. Reconstruction of the radiocapitellar joint is easier using external fixation since accurate correction of the ulna can be determined empirically and active functional exercises started immediately. Only patients with a radial head of normal shape were selected for treatment by this method. (+info)
A variant of mirror hand. A case report.
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We describe a rare variant of mirror hand in a 20-year-old man who presented with multiple fingers. Radiographs revealed two ulnae (one vestigial) and a radius. There was duplication of the humeral head. The unique features of this case are the age of patient before the start of treatment and extension of the duplication proximal to the elbow. (+info)
Dentin matrix protein 1 gene cis-regulation: use in osteocytes to characterize local responses to mechanical loading in vitro and in vivo.
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Dentin matrix protein 1 (DMP1) is highly expressed in osteocytes and is mechanically responsive. To study osteocyte-specific and mechanically regulated DMP1 gene expression, the transcriptional activity of three cis-regulatory regions was first examined in an osteoblast differentiation model in vitro using a green fluorescent protein (GFP) reporter. Expression of the -9624 to +1996 bp (10 kb) and -7892 to +4439 bp (8 kb) DMP1 cis-regulatory regions dramatically increased in areas of mineralized matrix, in dendritic, osteocyte-like cells. Mineralizing cultures expressing the 8-kb construct show dramatic GFP increases in response to loading in cells with a dendritic morphology. Transgenic mice expressing the 8-kb DMP1-GFP and -2433 to +4439 bp (2.5 kb) DMP1-LacZ were generated. Osteocyte-specific expression was found with the 8 kb but not with the 2.5 kb in postnatal animals. However, the 2.5 kb could support expression in rapidly forming osteoblasts and pre-osteocytes in the embryo. Primary calvarial osteoblast cultures demonstrated that the 2.5 kb supports weak expression in a subset of osteoblasts and pre-osteocytes, but not in mature osteocytes. However, the 8 kb supports robust expression in primary bone marrow cultures. Therefore the region -7892 to -2433 bp, termed a 5.5-kb "Osteocyte Enhancer Module," appears to be required for osteocyte specificity. Ulnae of mice with the 8-kb DMP1-GFP were subjected to mechanical loading where GFP expression increased selectively and locally in osteocytes, distal to the mid-shaft and near the surface of the bone. Thus, the 8-kb region of the DMP1 gene is a target for mechanotransduction in osteocytes, and its cis-regulatory activity may be correlated to local strain in bone. (+info)
Distribution of small proteoglycans and glycosaminoglycans in humerus-related articular cartilage of chickens.
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The expression of components present in the cartilaginous extracellular matrix is related to development, gender, and genotype, as well as to the biomechanical properties of each type of cartilage. In the present study, we analyzed small proteoglycans and glycosaminoglycans present in different cartilages of the chicken wing after extraction with guanidine hydrochloride or papain. Quantitative analysis of glycosaminoglycans showed a larger amount in humeral cartilage (around 200 mg/g tissue) than in articular cartilage of the radius and ulna, with 138 and 80 mg/g tissue, respectively. Non-collagenous proteins isolated were predominantly from cartilage in the proximal regions of the humerus and radius. D4 fractions obtained by ultracentrifugation were separated by DEAE-Sephacel and Octyl-Sepharose chromatography and analyzed by SDS-PAGE. Two bands of 57 and 70-90 kDa were observed for all samples treated with beta-mercaptoethanol. Immunoblotting of these proteins was positive for the small proteoglycans fibromodulin and decorin, respectively. Apparently, the 57-kDa protein is present in macromolecular complexes of 160 and 200 kDa. Chondroitin sulfate was detected in all regions. HPLC analysis of the products formed by chondroitinase AC and ABC digestion mainly revealed beta-D-glucuronic acid and N-acetyl beta-D-galactosamine residues. The 4-sulfation/6-sulfation ratio was close to 3, except for the proximal cartilage of the radius (2.5). These results suggest functional differences between the scapula-humerus, humerus-ulna, and humerus-radius joints of the chicken wing. This study contributes to the understanding of the physiology of cartilage and joints of birds under different types of mechanical stress. (+info)
Zoledronic acid causes enhancement of bone growth into porous implants.
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The effect of zoledronic acid on bone ingrowth was examined in an animal model in which porous tantalum implants were placed bilaterally within the ulnae of seven dogs. Zoledronic acid in saline was administered via a single post-operative intravenous injection at a dose of 0.1 mg/kg. The ulnae were harvested six weeks after surgery. Undecalcified transverse histological sections of the implant-bone interfaces were imaged with backscattered scanning electron microscopy and the percentage of available pore space that was filled with new bone was calculated. The mean extent of bone ingrowth was 6.6% for the control implants and 12.2% for the zoledronic acid-treated implants, an absolute difference of 5.6% (95% confidence interval, 1.2 to 10.1) and a relative difference of 85% which was statistically significant. Individual islands of new bone formation within the implant pores were similar in number in both groups but were 69% larger in the zoledronic acid-treated group. The bisphosphonate zoledronic acid should be further investigated for use in accelerating or enhancing the biological fixation of implants to bone. (+info)
Development of the subchondral bone layer of the medial coronoid process of the canine ulna.
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The medial coronoid process (MCP) of the ulna takes part in the weight-bearing function of the elbow in quadrupedal animals. In this study, the timing of development of a solid subchondral bone layer (SBL) of the MCP in the dog is investigated, as this might be important in the pathogenesis of the fractured medial coronoid process, a common disease in young dogs of larger breeds. The SBL is considered to make an important contribution to the strength of the MCP. In this study, the SBL is visualized at the humeral articular side (H-side) and in the radial notch (RN) via three-dimensional reconstructions of micro-CT scans (34 mum voxel size) in nine young golden retrievers. After micro-CT scanning, the area was investigated histologically. Gradually, the appearance of the SBL on the H-side changes from a trabecular aspect to an even surface with gaps and finally to a completely even surface. The surface in the RN is still rough at 24 weeks after birth, although some consolidation has occurred. Initially, the enchondral ossification activity, as observed in the histological sections, is high, but later, when the intertrabecular spaces are filled in with calcified cartilage and bone, activity is less evident. Some vessels penetrated the SBL, but it is unclear if they account for all the gaps in the surface seen in micro-CT. In addition, the formation of a cortical structure of the proximal ulnar shaft could be visualized. The bony cortex is already even at the mediocaudal side of the proximal ulna 4 weeks after birth, but remains trabecular at the dorsal side until 6 weeks later. We hypothesize that the observed differences in the formation of an even SBL or cortex can be explained by mechanical factors. A smooth cortical layer has an even thickness and will be stronger than a cortex with varying thickness. In the MCP, compressive forces exerted by the humerus may be responsible for the early smoothening on the H-side. In the proximal ulna, the resistance to bending in the sagittal plane will depend mainly on the caudal surface of the ulna (and dorsal surface of the radius), surfaces furthest away from the neutral axis. At least the caudal ulna smoothened first, thus providing stiffness against bending at an early age. (+info)
Ulnar focal cortical indentation: a previously unrecognised form of ulnar dysplasia.
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Deformity of the forearm due to growth disturbance of the ulna occurs in a number of conditions such as ulnar deficiency, multiple exostoses, and neurofibromatosis. We report a previously unrecognised form, caused by focal cortical indentation. We have treated five children with this condition, three girls and two boys; the mean age at presentation was 5 years (2 to 8). The deformity was first recognised about the age of two years, and progressed gradually. The radiological findings were the same in all cases. The focal cortical indentation was seen at the distal end of the ulna with anteromedial bowing and dysplasia. The radial head was dislocated posterolaterally. In one patient the histological findings at the site of indentation were of a fold of tissue resembling periosteum, which interfered with enchondral ossification. Treatment by ulnar lengthening using an external fixator and osteotomy which corrected both the ulnar deformity and reduced the dislocated radial head in two cases gave the best results. (+info)
A new syndrome, congenital extraocular muscle fibrosis with ulnar hand anomalies, maps to chromosome 21qter.
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BACKGROUND: Congenital fibrosis of the extraocular muscles (CFEOM) is a heterogeneous group of disorders that may be associated with other anomalies. The association of a CFEOM syndrome with ulnar hand abnormalities (CFEOM/U) has not been reported to date. OBJECTIVE: To describe a new autosomal recessive syndrome of CFEOM and ulnar hand abnormalities, and localise the disease causing gene. METHODS: Clinical evaluation of the affected members and positional mapping. RESULTS: Six affected patients with CFEOM/U (aged 2 to 29 years) from a large consanguineous Turkish family were studied. Ophthalmological involvement was characterised by non-progressive restrictive ophthalmoplegia with blepharoptosis of the right eye. The postaxial oligodactyly/oligosyndactyly of the hands was more severe on the right side. A genome-wide scan established linkage of this new autosomal recessive syndrome to a locus on chromosome 21qter. The multipoint LOD score was 4.53 at microsatellite marker D21S1259, and fine mapping defined a approximately 1.5 Mb critical region between microsatellite marker D21S1897 and the telomere of the long arm. CONCLUSIONS: CFEOM/U maps to a 1.5 Mb region at chromosome 21qter. Future identification of the disease causing gene may provide insights into the development of the extraocular muscles and brain stem alpha motor neurones, as well as anteroposterior limb development. (+info)