摘要:

AbstractThe goal of treating patients with skeletal metastases is to decrease pain and improve or maintain physical function. Assessment of the effectiveness of treatment should therefore include evaluation of patient‐rated measures of quality of life. The primary objective of the study was to determine the feasibility of studying the effect of surgical treatment of skeletal metastases on quality of life. The secondary objective was to provide data that begin to characterize this effect. The characteristics of patients with skeletal metastases are heterogeneous, patient enrollment in the study may be low, high attrition occurs secondary to death, and well accepted health‐status measures (such as the Short Form‐36) may be ineffective at detecting changes in health status: therefore, it is difficult to study these patients. High attrition and adjuvant treatment with radiation or chemotherapy made it impractical to draw firm conclusions about the effect of surgical treatment, but a trend toward improvement in selected health‐status measures for both physical and mental health was noted. Analysis of patient‐rated health‐status scores as predictors of survival indicates that improvement in these scores 6 weeks after surgery is associated with an increase in the length of survival follow

ISSN:0736-0266    

DOI:10.1002/jor.1100180102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractOsteosarcoma is one of the most common primary malignant tumors of bone. Treatment of this tumor with systemic chemotherapy dramatically improves the prognosis, although the molecular mechanisms involved in the drug action are poorly understood. In chemosensitive leukaemic T cells and certain solid tumors. cytotoxic drugs mediate the induction of apoptosis by activation of the CD95/APO‐1/Fas system. Triggering of the corresponding signaling pathway may involve CD95‐receptor/ligand interaction, activation of caspases, or alterations in mitochondrial function. The purpose of our study was to determine if similar mechanisms are involved in the chemosensitivity of osteosarcomas. We found that cytotoxic drugs induce characteristic biochemical and morphological alterations related to apoptosis in osteosarcoma cell lines, including activation of caspases and disturbance of mitochondrial function. However, drug treatment did not result in activation of CD95‐receptor or CD95‐ligand mRNA. In addition, drug‐induced apoptosis was blocked by caspase inhibitors but not by inhibition of CD95‐ligand action, indicating a CD95‐receptor/ligand‐independent mechanism in osteosar

ISSN:0736-0266    

DOI:10.1002/jor.1100180103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractFour sequential bone‐marrow aspirations from the ipsilateral tibia and iliac crest of New Zealand White rabbits, aged 4 months or 1, 2, or 3 years, were assayedin vitroandin vivofor their chondroosteogenic potential. Nonhematopoietic cells from the samples of bone marrow were isolated and expanded in culture: their colony‐forming efficiency was determined, and second‐passage marrow‐derived cells, referred to as mesenchymal progenitor cells, were loaded into porous calcium‐phosphate ceramic cubes as carrier vehicles for anin vivocartilage and bone‐formation assay. The cubes were placed subcutaneously in nude BALB/C mice for 3 and 6 weeks. On histological examination, the cubes were scored for the presence of bone and cartilage in their pores, and average values for age groups and location were compared. At aspiration, the samples from the iliac crest exhibited an overall reduction in cell concentration with increasing age, and at the first harvest time, they showed a decrease in colony‐forming efficiency and cube score with increasing age. This study demonstrated that repeated bone‐marrow aspirations may be performed and may have an enhancing effect on the osteochondral progenitor cells o

ISSN:0736-0266    

DOI:10.1002/jor.1100180104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractIt is well established that the reparative potential of many tissues is greatest during embryonic development. Despite the extensive literature documenting repair in nonembryonic cartilage models, there is no comparable wealth of experience relating to embryonic cartilage repair. With the embryonic chick sternum as a model of hyaline cartilage, this paper accounts cellular responses and alterations in extracellulat matrix composition in response to experimental woundingin vitro.Creation of an experimental lesion induced a rapid (<20 minutes) apoptotic response in chondrocytes adjacent to the lesion edge; the presence of perichondrium delayed this response. Alterations in the extracellular matrix included immediate mechanical damage to type‐II collagen fibrils and an increase in the expression of chondroitin‐4 sulphate next to the lesion. Creation of the lesion induced an increased proliferative response in chondrocytes behind the zone of apoptosis and the expression of α5 and α6 integrin sub

ISSN:0736-0266    

DOI:10.1002/jor.1100180105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractThe weight of patients has not been demonstrated to have a consistent effect on the rate of polyethylene wear in clinical studies of total joint replacement. For this reason, we analyzed the relationship beetween quantitative activity, measured with a pedometer, and body mass index, a measure of obesity. Data were acquired for 209 individuals, 22‐82 years of age; all were independent community walkers. One hundred and fifty‐one had a well functioning total hip or knee replacement. Analysis of variance was used to evaluate the relationship between activity and body mass index, with adjustments for confounding variables. The 58 individuals with no total joint prosthesis averaged 7,781 steps per day, which was higher (p<0.01) than those with a total hip (5,869 steps per day) or knee (4,597 steps per day) replacement. The subjects with no total joint prosthesis were, however, younger than the patients with a prosthesis (p<0.01), and the body mass index of the patients with a total knee replacement was higher than that of the patients with a hip replacement and that of the subjects with no prosthesis (p<0.01). After adjustment for differences in age, gender, and Charnley class, a higher body mass index (greater obesity) was associated with lower activity (p = 0.05). With regard to the rate of polyethylene wear, decreased ambulatory activity may counterbalance increased weight, which could, at least in part, explain why weight has not had a consistent effect on polyethylene wear in clinical studies. Wear is a function of use, not time. The effect of obesity on activity should be considered in radiographic studies of wear and other outcome assessments of total joint replaceme

ISSN:0736-0266    

DOI:10.1002/jor.1100180106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractThe change in bone mineral density at the proximal tibia during 2 years after total knee arthroplasty was studied in 28 knees (28 patients: 10 men and 18 women; median age: 71 years) with dual energy x‐ray absorptiometry. Bone mineral density was measured at the proximal tibia at nine regions of interest below the tibial component within 1 week after the operation (baseline); measurements were repeated at 3, 6, 12, and 24 months. All but one knee was malaligned before the operation, and all but three were corrected to within the normal range of alignment after it. The mean bone mineral density of all nine regions of interest at the proximal tibia temporarily decreased by 13% (p = 0.001) during the initial 3 months, probably due to a general metabolic reaction of the skeleton to the operative trauma combined with the effect of the postoperative immobilization, and then the initial level was regained for as long as 2 years. The overall changes in mean bone mineral density to 2 years were insignificant (p>0.05); however, a great variation (43.9% decrease to 98.0% increase) was observed on an individual basis. This change over time was significantly associated (R2= 0.36, p = 0.002) with the level of the baseline bone mineral density, which in turn was partly related (R2= 0.24, p = 0.009) to the amount of malalignment of the knee before the operation. Knees with high baseline levels (n = 14: 11 with varus and three with valgus alignment) displayed a decrease of 10.0 ± 14.0% (mean ± SD, p>0.05) for as long as 2 years, whereas those with low baseline levels (n = 14: seven with varus and six with valgus alignment and one neutrally alignment and one neutrally aligned) had an increase of 19.1 ± 38.2% (p = 0.038). In both groups, the mean bone mineral density converged to a level of 0.75–0.95 g/cm2at 2

ISSN:0736-0266    

DOI:10.1002/jor.1100180107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractTotal knee replacements using intercondylar cams, such as posterior stabilized types, have been in use for many years. In a previous study, software was written to analyze an alternative shape of the intercondylar cams. The goal of the current study was to investigate in a more general way the potential of intercondylar cams, or guide surfaces, for reproducing the anterior‐posterior motion of the natural knee throughout the flexion range. Typical sagittal outlines for the femoral and tibial bearing surfaces were defined, and a parametrized shape for the femoral guide surface was defined to produce a wide range of shapes. Software was written in which the femoral component was flexed in increments, with the posterior translation defined as a function of the flexion angle. The shape of the tibial guide surface was derived from the locus of the femoral guide surface at its multiple flexion positions. By iterating methodically through possible shapes of femoral guide surfaces, several types of total knee replacement components in common use today were identified, as well as other configurations of potential interest. For quantification of a given design, the software calculated the anterior and posterior laxity at each flexion angle. Laxity was defined as the motion before the femoral guide surface impacted the tibial guide surface or until the contact point of the bearing surfaces reached a specified slope. Convex femoral and concave saddle‐shaped tibial guide surfaces produced small laxities in both directions over most of the flexion range. A saddle design with small laxities in the first half of flexion, combined with a posterior stabilized feature, was an interesting combination. Potential improvements to the currently used designs were shown in this study and new shapes of intercondylar guide surfaces were derived that could be considered for applicat

ISSN:0736-0266    

DOI:10.1002/jor.1100180108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractThis study used radiography, gait analysis, gluteal muscle mass, mechanical testing, and qualitative histology to compare three methods of gluteal muscle attachment to an allograft/endoprosthetic composite of the proximal 25% of the femur in anin vivocanine model. The three methods of gluteal muscle attachment were identical to those used clinically in human patients for hip revision and proximal femoral limb salvage: the host gluteal tendon sutured to the allograft tendon (tendon group), the host greater trochanter with intact gluteal tendons secured to the allograft with a cable‐grip system (grip group), and periosteally vascularized proximal femoral bone onlay with intact tendons wrapped around the allograft (wrap group). On the basis of radiographs taken every 2 months, the tendon group had more graft fractures than did the grip or wrap group. Radiographic union of the graft‐host bone junction occurred more rapidly and there was less graft resorption in the wrap group than in the other two groups. In all dogs, peak vertical ground‐reaction forces in the treated limb decreased immediately after surgery and then slowly increased over the length of the study. The dogs in the wrap group regained normal weight‐bearing on the treated limb more quickly than did those in the other groups. The constructs in the tendon group were weaker and less stiff immediately after surgery than were those in the other groups or in intact controls. Histologic analysis confirmed that the wrap technique resulted in complete union of the host bone‐allograft junction more often than did the other techniques. The wrap method had the best functional outcome after 9 months when an allograft/endoprosthetic composite was used during total hip arthroplasty in this can

ISSN:0736-0266    

DOI:10.1002/jor.1100180109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to determine whether a marker of bone resorption could be used noninvasively to diagnose and assess treatment of periprosthetic osteolysis. The crosslinked N‐telopeptide marker of osteoclast‐mediated bone resorption potentially has the sensitivity to detect periprosthetic osteolysis. Second‐morning urine specimens were obtained from (a) seven age‐matched controls, (b) eight patients who had a hip arthroplasty, hybrid implants at least 1 year after surgery, and no osteolysis, (c) 11 patients who had a hip arthroplasty and osteolysis, and (d) 10 patients who had a hip arthroplasty and with osteolysis before and after 6 weeks of oral Fosamax (alendronate) treatment. The Fosamax treatment consisted of one 10‐mg dose per day for 6 weeks. Men and young women (less than 40 years old) were chosen for this study to avoid bone resorption enhanced after menopause as a possible confounder. An enzyme‐linked immunosorbent assay technique for quantifying crosslinked N‐telopeptides of type‐I collagen was performed on all specimens. The patients with osteolysis had significantly elevated levels of N‐telopeptide compared with the implant control group. In addition, levels of N‐telopeptide were significantly lowered after Fosamax treatment. These findings indicate that a systemic bone‐resorption marker (N‐telopeptide) can be used to evaluate local particulate‐induced osteolysis and its treatment. The study also provides clinical evidence that osteolysis is associated with increased osteoclast‐mediated bone resorption and that this locally induced bone resorption can be suppressed by certain bisphosphonates (Fosamax). These insights have potential value in the understanding and clinical mana

ISSN:0736-0266    

DOI:10.1002/jor.1100180110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractAutologous transplantation of chondrocytes is currently under investigation as a potential therapy to stimulate intrinsic repair in articular cartilage defects. The quality of the repair tissue may benefit from the preservation of the characteristic chondrocytic phenotype of the transplanted cells together with the production of a new extracellular matrix composed of collagen type II and larger proteoglycans. A number of growth factors are believed to play an important role in the process of generating new cartilage repair tissue. In this study. the dose‐dependent response of bovine chondrocytes to recombinant human insulin‐like growth factor‐1, recombinant human transforming growth fac or‐β2, and recombinant human bone morphogenetic protein‐2 was studied in an alginate culture system under different culture conditions. The chondrocytes were cultured in medium with increasing concentrations of fetal calf serum. The cultures were assessed by the total amount of DNA, quantitative and qualitative synthesis of proteoglycan, production of nitric oxide, and histology, Cells cultured in the presence of each growth factor had an equal, nonsignificant stimulation of DNA synthesis compared with those cultured in basal medium alone. Recombinant human insulin‐like growth factor‐1 and recombinant human transforming growth factor‐β2 stimulated proteoglycan synthesis in a dose‐dependent and reversed dose‐dependent fashion, respectively. Recombinant human bone morphogenetic protein‐2 stimulated proteoglycan synthesis significantly only in the absence of fetal calf serum or in the presence of small amounts of the serum. Overall, proteoglycan synthesis dramatically decreased with the addition of each growth factor as the concentration of fetal calf serum in the medium decreased, and the dose‐dependent stimulation pattern, as observed for recombinant human insulin‐like growth factor‐1 and recombinant human transforming growth factor‐β2, disappeared. Apart from a moderate increase in mRNA for aggrecan and decorin, the growth factors did not greatly affect the type of proteoglycans synthesized. Histological examination confirmed the presence of a dense pericellular matrix deposition, especially when the chondrocytes were cultured in the presence of recombinant human insulin‐like growth factor‐1 or recombinant human transforming growth factor‐β2. The results indicate that these growth factors can stimulate qualitatively superior matrix production and that the responsiveness of the chondrocytes to the growth factors changes with the culture conditions. Further knowledge about the interaction between chondrocytes, growth factors, and the external environment is important to stimulate chondrocytes to produce adequate repair tissue in cartilage defectsin vivo.Insulin‐like growth factor‐1 especially seems capable of stimulating, in the most consistent and predictable fashion, qualitatively superior proteoglycan synthesis by differentiated chondrocytes. Additionalin vivostudies are needed to evaluate the potential of these growth

ISSN:0736-0266    

DOI:10.1002/jor.1100180111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY