Cervical myelopathy caused by hypoplasia of the atlas and ossification of the transverse ligament--case report.
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A 79-year-old Japanese female presented with symptomatic cervical myelopathy caused by a hypoplastic posterior arch of the atlas and ossification of the transverse ligament. Neuroradiological examination demonstrated a hypoplastic posterior arch of the atlas and ossification of the transverse ligament. The cervical spinal cord was compressed at the level of the atlas by both the hypoplastic posterior arch of the atlas and the ossification of the transverse ligament. The patient underwent C-1 laminectomy, which arrested the progressive myelopathy and resulted in a good recovery. Atlas hypoplasia with ossification of the transverse ligament may be associated with Asian ethnicity. (+info)
A ten- to 15-year follow-up of the cementless spotorno stem.
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We followed the first 354 consecutive implantations of a cementless, double-tapered straight femoral stem in 326 patients. Follow-up was at a mean of 12 years (10 to 15). The mean age of the patients was 57 years (13 to 81). At follow-up, 56 patients (59 hips) had died, and eight (eight hips) had been lost to follow-up. Twenty-five hips underwent femoral revision, eight for infection, three for periprosthetic fracture and 14 for aseptic loosening. The overall survival was 92% at 12 years (95% CI 88 to 95). Survival with femoral revision for aseptic loosening as an endpoint was 95% (95% CI 92 to 98). The median Harris hip score at follow-up was 84 points (23 to 100). Radiolucent lines (< 2 mm) in Gruen zones 1 and 7 were present in 38 (16%) and 34 hips (14%), respectively. Radiolucencies in zones 2 to 6 were found in five hips (2%). The results for mid- to long-term survival with this femoral component are encouraging and compare with those achieved in primary cemented total hip arthroplasty. The high rate of loosening of the cup and the high rate of pain are, however, a source of concern. (+info)
Changes in subchondral bone in cartilage resurfacing--an experimental study in sheep using different types of osteochondral grafts.
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OBJECTIVE: This article addresses the subchondral bone integrity in cartilage resurfacing by comparing fresh, untreated auto-, xeno-, and photooxidized osteochondral allo- and xenografts. Photooxidation was expected to improve mechanical stability of the osteochondral grafts through an improved linkage of the collagen fibers within the bone matrix. DESIGN: Untreated auto- and xenografts and with photooxidation pretreated allo- and xenografts were surgically implanted in femoral condyles of sheep (n=40). After 2, 6, 12 and 18 months results were evaluated histologically using non-decalcified bone embedded in acrylic resin. Qualitative evaluation was performed with emphasis on bone matrix, biomechanical stability of graft anchorage, formation of cystic lesions, and bone resorption and formation. Quantitative evaluation of the total subchondral bone area was conducted histomorphometrically. Statistical analysis (factorial ANOVA test) was used to compare differences between groups with respect to the percentage of bone matrix and fibrous tissue per section. RESULTS: Subchondral bone resorption was fastest in untreated, fresh autografts, followed by photooxidized allografts, untreated, fresh xenografts and last pretreated photooxidized xenografts. Cystic lesions were seen in all types of grafts, but were most pronounced at 6 months in autografts and least in photooxidized grafts. Cyst-like lesions had subsided substantially in the untreated auto- and photooxidized xenografts, if no graft dislocation occurred during the healing period. Mononuclear cell infiltration and an increase in the presence of multinuclear cells were observed at 2 months, mostly in untreated autografts, followed by photooxidized allo- and untreated xenografts. They were much higher in numbers compared to photooxidized grafts, at least in the early specimens at 2 months. Graft stability was linked to the rate of bone resorption. CONCLUSION: Substantial resorption of the subchondral bone, involving the development of cyst-like lesions, lead to dislocation and finally to cartilage matrix degradation of the grafts. The process of photooxidation decreased the speed of bone resorption in osteochondral grafts and, thus, improved graft stability and cartilage survival. These results suggest that the remodeling of the subchondral bone of the host and the graft within the first 6 months is an important factor in graft stability and overall results of cartilage resurfacing. (+info)
Subependymomas in children: a report of five cases including two with osseous metaplasia.
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Subependymomas are highly differentiated slow growing gliomas. They are one of the few gliomas which are biologically benign. They are extremely rare in children. However, after going through the histopathology records of our department of fourteen years (1983-1997) we found that five (20%) cases of subependymomas have been diagnosed in children out of a total of twenty-six subependymomas. Two of our cases showed the presence of osseous metaplasia, a hitherto undescribed finding. (+info)
Heterotopic ossification prophylaxis with indomethacin increases the risk of long-bone nonunion.
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Indomethacin is commonly administered for the prophylaxis of heterotopic ossification (HO) after the surgical treatment of acetabular fractures. Non-steroidal anti-inflammatory drugs such as indomethacin, have been associated with delayed healing of fractures and mechanically weaker callus. Our aim was to determine if patients with an acetabular fracture, who received indomethacin for prophylaxis against HO, were at risk of delayed healing or nonunion of any associated fractures of long bones. We reviewed 282 patients who had had open reduction and internal fixation of an acetabular fracture. Patients at risk of HO were randomised to receive either radiation therapy (XRT) or indomethacin. Of these patients, 112 had sustained at least one concomitant fracture of a long bone; 36 needed no prophylaxis, 38 received focal radiation and 38 received indomethacin. Fifteen patients developed 16 nonunions. When comparing patients who received indomethacin with those who did not, a significant difference was noted in the rate of nonunion (26% v 7%; p = 0.004). Patients with concurrent fractures of the acetabulum and long bones who receive indomethacin have a significantly greater risk of nonunion of the fractures of the long bones when compared with those who receive XRT or no prophylaxis. (+info)
Vitamin A and endochondral ossification in the rat as indicated by the use of sulfur-35 and phosphorus-32.
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The administration of vitamin A to vitamin A-deficient rats resulted in a decreased concentration of inorganic sulfate-sulfur in the serum from a value of 2.5 mg. per cent to 1.8 mg. per cent, the latter being close to the value of 2.0 mg. per cent found in normal rats of the same age. The uptake of sulfate and phosphate by femurs and tibiae of vitamin A-deficient rats was less than that in normal rats of the same age. An increased uptake followed the administration of vitamin A: radioautography indicated that in the case of sulfate, its uptake was particularly increased in the epiphyseal cartilage; an increased uptake of phosphate was particularly evident in the diaphysis immediately adjacent to the epiphyseal cartilage plate. The specific activity of the sulfate-sulfur in the chondroitin sulfate samples isolated from the skeletons of vitamin A-deficient rats fell progressively as the deficiency continued. Following administration of vitamin A, the specific activity approached and exceeded the value given by the sample from the skeletons of normal rats of the same age. A substantial increase was found in the value of the specific activity of the sulfate-sulfur of sulfomucopolysaccharides isolated from skins of vitamin A-deficient rats that had been given vitamin A. Following administration of vitamin A to rats deficient in this vitamin, an increased accumulation of some sulfur-containing material was found in regions of active calcification. (+info)
Vitamin D and endochondral ossification in the rat as indicated by the use of sulfur-35 and phosphorus-32.
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The concentration of inorganic sulfate-sulfur in the serum of vitamin D-deficient rats, 2.6 to 3.5 mg. per cent, was found to be higher than that in the serum of normal rats of the same age, 2.0 mg. per cent. No change was observed following the administration of 25 gamma of vitamin D(2). In accord with the results of others, it was found that a definitely increased deposition of phosphorus in femurs and tibiae had occurred 36 to 48 hours after the administration of vitamin D(2) to vitamin D-deficient rats. An immediate increase in the uptake of sulfate by the skeleton was found using sodium sulfate-S(35). As measured by the specific activity of sulfate-sulfur in samples of chondroitin sulfate isolated from the skeletons of the vitamin D-deficient animals and from normal controls receiving equal doses of sulfur-35, the rate of synthesis of chondroitin sulfate in rachitic rats is similar to the rate in normal rats of the same age. Likewise, the incorporation of labelled sulfate into the sulfomuco-polysaccharides of the pelts was found to be equal at 12 hours to that in normal rats. Following the administration of vitamin D(2) to deficient animals an increase in the rate of synthesis of the chondroitin sulfate of the skeletons was noted. The radiochemical and radioautographic evidence suggest that there is in vitamin D-deficient rats an impaired utilization of chondroitin sulfate and that vitamin D(2) is able to accelerate this process. (+info)
Cell proliferation and specialization during endochondral osteogenesis in young rats.
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Endochondral osteogenesis was studied autoradiographically in ribs and tibiae of 32 Long-Evans rats injected with 1 microc/gm H(3)-thymidine at 6 days of age and sacrificed at intervals between 1 hour and 2 weeks later. Proliferation and specialization of bone cells were studied by analyses of (a) the percentage of mitoses which were labeled, (b) the percentage of labeled nuclei in bone cells, and (c) grain counts. The following conclusions were derived: The various types of bone cells represent different functional states of the same cell. Cell division is usually restricted to cells in the morphologically unspecialized "osteoprogenitor" state. Specialized bone cells arise by modulation of osteoprogenitor cells. The average cell generation time is shortest in the metaphysis, longest in the periosteum, and intermediate in the endosteum. The average duration of DNA synthesis is relatively constant (about 8 hours). With increasing length of generation time there is a slight increase in G(2) + mitosis, but the major change is a lengthening of G(1). After dividing, cells in the osteoprogenitor state may remain within the progenitor pool or undergo modulation of cell type, specializing as osteoblasts or becoming incorporated in osteoclasts. (+info)