摘要:

AbstractThe assessment of patients following prosthetic knee replacement suffers from a lack of objective criteria. An automated method of laboratory assessment that permits the objective evaluation of knee joint function is described. Nine biomechanical parameters were statistically selected, weighted, and combined to develop a Performance Index (Ip). One hundred ninety‐two patients (274 diseased knees) were studied prior to total knee replacement surgery, with 107 patients (138 knees) returning for a 1‐year postoperative study. Preoperative rheumatoid knees were found to have significantly poorer function than those involved with degenerative disease. Overall, the patients experienced a marked improvement 1 year post‐total knee replacement (TKR), with their functional scores approaching the lower limits of normal. Prostheses were assessed according to generic classes as well as specific design types. The newer generation devices were found to produce better functional results. In the patients receiving Anametric and Total Condylar total knee devices, a patellar resurfacing component was found to produce improved knee function in comparison with patients receiving the same prosthesis but without patellar resurf

ISSN:0736-0266    

DOI:10.1002/jor.1100020401

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

年代:1984

数据来源: WILEY

摘要:

AbstractThis is a cross‐sectional study of bone densitometry in>700 normal healthy white women ranging in age from 18 to 98 years. A modified procedure for single–photon bone density analysis of the distal radius is described and compared with dual‐photon densitometric measurements of the second through fourth lumbar vertebrae. The distal radial site measured was separated from the ulna by 5 mm. This “5 mm” site was characterized according to trabecular and cortical bone content, measurement reproducibility, positioning precision, and the effects of wrist pronation or supination. The radial site demonstrated a bone density loss of<0.1%/year for normal women 25–50 years of age, increasing to 0.7%/year after 50 years of age. In contrast to the variability and inconsistency obtained by us and others utilizing the standard “9/10” site, bone loss with age at the new “5 mm” site correlated closely with generalized bone mineral loss of the axial skeleton. We suggest that there is a unique role for single‐beam densitometric measurements of the radius, permitting the rapid and relatively inexpensive evaluation of large populations of women without requiring a visit to a medical center. Such a process can select those requiring further evaluation

ISSN:0736-0266    

DOI:10.1002/jor.1100020402

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

年代:1984

数据来源: WILEY

摘要:

AbstractThis study measured radial and lumbar spine bone density in postmenopausal white female patients with nontraumatic fractures and their agematched controls. Bone density measurements were made with a single‐beam densitometer. Distal radial bone density measurements were made at the site at which the radius and ulna are separated by 5 mm, which is ∼5 mm from the distal radioulnar joint. Lumbar spine density was obtained using a dualbeam densitometer. Density at the commonly used “2/3” site near the midradius was also measured. Forty‐six crush fracture osteoporotic patients, 35 hip fracture patients, and 20 osteopenic patients referred to the clinic for back pain or excessive bone loss but with no history of nontraumatic fracture were studied. Bone density values at all sites in the patient populations were statistically reduced from control values (p<0.01). At a mean age of 62 years, density of the midradius was 12% below the control value. However, both vertebral and distal radial densities (“5 mm” site) were 25% below control values. The spine/distal radius ratio remained constant. It was demonstrated that bone density at the modified distal radial site could be used to predict vertebral density in osteopenic patients. An “at risk” value useful in screening procedures was determined as that distal radius density value ⩾95% of all values from fracture patients—325 mg/cm2. It is concluded that distal radial density at the new “5 mm” site can be used in conjunction with midradius density as a preliminary test for both generalized and trabecula

ISSN:0736-0266    

DOI:10.1002/jor.1100020403

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

年代:1984

数据来源: WILEY

摘要:

AbstractBone density was studied in intercollegiate athletes and older athletic women. Single‐photon densitometry was used to assess bone density parameters at a new distal radial site, the midradius, and the first metatarsus. Dual‐photon densitometry assessed bone density of the lumbar spine. Eleven intercollegiate tennis players, 23 swimmers, and 86 older “athletic” women from 23 to 75 years of age were compared with age‐matched nonathletic controls. “Athletic” describes adult women who exercised at least three times per week, 8 or more months of the year, for a minimum of 3 years. The radius and metatarsus bone content of intercollegiate athletes was significantly above control values. Lumbar spine density was significantly higher only in tennis players. Mean bone density values for adult “athletic” women were also significantly greater than in age‐matched controls. In the oldest athletic group (55–75 years of age) bone measurement values in radius and lumbar spine were in the same range as for younger “athletic” women. In contrast, after 50 years of age, these values in the control population decreased by 0.7%/year. Therefore the largest variance (increase) from age‐matched controls occurred in the oldest “athletic” group. Also, we have established a distal radial density value (using our modified site) below which we consider women “at risk” and recommend further bone health evaluation. Only two adult athletic women>55 years of age fell into this category. It is concluded from this cross‐sectional study that a regularly maintained athletic program for adult women may reduce the rate of “normal” bone mass loss accompanying age, particularly postmenopausally. Whether this will also decrease the risk of nontraumatic fractur

ISSN:0736-0266    

DOI:10.1002/jor.1100020404

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

年代:1984

数据来源: WILEY

摘要:

AbstractBreeding experiments confirmed that a hereditary form of kyphoscoliosis in the BDL strain mouse was due to an autosomal recessive gene (ky). Sagittal sections of whole vertebral columns from adult homozygous recessive mice (ky/ky) were examined histologically. All mice showed varying degrees of degenerative change in one or more intervertebral discs between the fifth cervical and the second thoracic vertebrae. The changes comprised loss of cells, loss of distinction between nucleus pulposus and annulus fibrosus, loss of characteristic ring‐like structure in the annulus, and development of wedge‐shaped discs. In most animals, degenerative disc substance protruded from the disc space, usually posteriorly, sometimes anteriorly, and occasionally through the vertebral end plate cartilage. Posterior protrusions impinged on the spinal c

ISSN:0736-0266    

DOI:10.1002/jor.1100020405

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

年代:1984

数据来源: WILEY

摘要:

AbstractWe have described a previously unrecognized chondrodystrophy characterized by short‐limbed dwarfism, blue sclera, severe cardiopulmonary problems, and failure of postnatal growth. The first of two siblings thus affected died at age 6 months following attempted correction of an atrial septal defect. Growth plate cartilage from multiple sites obtained at autopsy showed a marked abnormality of architecture on the light microscopic level. Biochemical studies demonstrated an absence of normal α 1(II) collagen in costochondral junction growth plate cartilage and an appearance of the major collagen in a band which comigrates on sodium dodecyl sulfate‐polyacrylamide gel electrophoresis with 3α collagen. Cartilage extracted from structural rib appeared to be n

ISSN:0736-0266    

DOI:10.1002/jor.1100020406

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

年代:1984

数据来源: WILEY

摘要:

AbstractAntibody synthesis by the arthritic synovium of rabbits with antigen‐induced arthritis has been demonstrated, but knowledge of the details of the specific localization of antibody in the membrane is limited. Specific antibody in the synovium of ferritin‐induced arthritis was detected by electron microscopic observation of bound ferritin. The specific antibodies were localized in the cisternae of the endoplasmic reticulum and perinuclear spaces within plasma cells. In the extracellular matrix, specific antibody was found distributed as a network within collagen bundles and in the basement membrane of the subsynovial small blood vess

ISSN:0736-0266    

DOI:10.1002/jor.1100020407

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe bipolar endoprosthesis was designed to alleviate problems encountered with conventional hip endoprostheses. Recent designs have advocated the use of offset centers of rotation between the inner and outer jointbearing surfaces to generate a valgus‐producing moment on loading (antivarus head dynamics). This study was undertaken to justify this biomechanical feature by performing (a) cyclic loading of the bipolar head in the varus position, (b) analysis of motion between the inner and outer bearing surfaces, and (c) evaluation of antivarus head dynamic function. Four endoprosthetic designs were studied: the Bateman UPF, Osteonics UHR, Giliberty II, and Bi‐Centric. Significant plastic deformation occurred in the UPF and UHR prostheses when loaded in an extreme varus position. Theoretically, motion is most likely to occur at the inner bearing if the frictional coefficients are equal at both surfaces. The UHR prosthesis with eccentric offset of bearing centers can provide the antivarus effect in laboratory conditions. Whether the antivarus effect and/or the dominant inner bearing motion will occurin vivoawaits careful clinical st

ISSN:0736-0266    

DOI:10.1002/jor.1100020408

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

年代:1984

数据来源: WILEY

摘要:

AbstractA finite element analysis of the Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF) intramedullary femoral nail was performed to study the failure of the nail from circumferential cracking near the slot tip. These failures are evidently the result of a stress‐concentrating effect owing to the partially slotted nail design. Several finite element models were created of the proximal one‐fourth of the nail. One model of the nail incorporated the cloverleaf profile as it is presently manufactured, and one had a circular cross section. An additional three models were created with alternative slot‐tip geometries: a narrowed slot, a tapered slot, and a widened slot. Antero‐posterior (AP) and medio‐lateral (ML) bending loads and torsion loads were applied in two fundamentally different loading modes: (1) loads that were applied on both sides of the slot tip (spanned); and (2) loads that were self‐equilibrating distal to the slot tip (non‐spanned). For the load cases studied, for all models, the stresses predicted from the finite element models were locally highest at the junction between the open and closed cross sections. Alternative slot‐tip shapes had a marked effect on the predicted stresses, in one case reducing maximum stress by 40%. However, no alternative slot tip shape was uniformly superior for all load cases. Therefore, until thein vivoloading modes are known more precisely, an alternative slot‐tip shape

ISSN:0736-0266    

DOI:10.1002/jor.1100020409

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe fatigue performance of several types of commonly used external fixator pins was examined. The pins were tested under a cyclic bending mode. A strength reduction factor (SRF) was defined to quantify the effect of stress concentration caused by the pin threads as compared with the smooth portion of the pin. The half pins tested had much higher SRF values than the corresponding full pins because of the smaller root diameter of the threaded regions. The use of finer threads and a cold rolling process appeared to increase the pin fatigue strength. In some pins, the depth markers on the smooth portion and the self‐tapping fluted region were sites of significant stress concentration. When certain half pins are severely loaded under clinical conditions, they may fracture because of fatigu

ISSN:0736-0266    

DOI:10.1002/jor.1100020410

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

年代:1984

数据来源: WILEY