摘要:

AbstractThe biomechanical properties of the rabbit medial collateral ligament (MCL) as a function of maturation and age were investigated. Femur–MCL–tibia (F‐M‐T) preparations were obtained from rabbits of different age groups (open or closed epiphysis). Parallel increases in the animal body weight and ligament cross‐sectional area were recorded with age. Cyclic and tensile failure tests were performed to obtain the structural properties of the F‐M‐T complex and the mechanical properties of the MCL substance. There were significant increases in the load at failure, energy‐absorbing capability of the bone–ligament junction, and in the tensile strength of the ligament substance as a result of maturation and subsequent aging. Increases in the area of hysteresis obtained during cyclic loading–unloading were also documented. At the closing of the epiphysis, the mode of failure of the F‐M‐T structure progressed from tibial avulsion to failure in the midsubstance of the ligament. An asynchronous rate of maturation was observed between the structural properties of the bone–ligament complex and the mechanical properties

ISSN:0736-0266    

DOI:10.1002/jor.1100040201

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe objectives of this study were (a) to describe the three‐dimensional in vivo kinematic behavior of wrists affected by rheumatoid arthritis, (b) to correlate kinematic parameters and two radiographic indices of carpal disease, and (c) to describe the in vivo kinematic behavior of the Swanson Silastic wrist implant. Fifteen normal wrists, 17 rheumatoid wrists, and 7 wrists with Silastic wrist implants were tested using a three‐dimensional sonic digitizing system. The motion of the hand segment relative to the forearm segment, corresponding to the positions exhibited during flexion‐extension motion (FEM) and radial‐ulnar deviation (RUD), was described using the equivalent screw displacement (ESD) concept. The mean magnitudes of ESD rotation for both FEM and RUD were statistically different (p0.05) among the normal, rheumatoid, and implant groups. The two radiographic indices (carpal collapse and carpal translation) did not correlate with the magnitude of rotation or with any other ESD pa

ISSN:0736-0266    

DOI:10.1002/jor.1100040202

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

年代:1986

数据来源: WILEY

摘要:

AbstractLoad‐displacement curves were measured for six types of pure force loading of the cervical spine specimens obtained from fresh human cadavers. A new measuring and mounting technique was developed that yielded data for all of the functional spinal units for each specimen tested. All five of the coupled, as well as the main, load‐displacement curves were studied. For anterior and posterior shear loadings, the main resulting motions were translation in that direction (1.6 ± 0.3 and 1.9 ± 0.3 mm), and the major coupled motions were flexion and extension (3.6° ± 1.2° and 6.3° ± 1.2°). The main motions with right and left lateral shear loadings were translations laterally (1.4 ± 0.3 and 1.6 ± 0.3 mm), and the major coupled motions were axial rotations (1.5° ± 0.6° and 2.3° ± 0.6°) and not lateral bending. For compression and distraction loadings, the main motions were translations in that direction (0.7 ± 0.3 and 1.1 ± 0.3 mm), and the major coupled motions were flexion and extension (2.0° ± 1.0° and 2.8° ± 1.0°) and lateral bending (1.4° ± 0.3° and 1.9° ± 0.3°). The neutral zones for anterior and posterior shear forces were 1.6 ± 0.2 mm of translation and 5.8° ± 1.3° of rotation, for lateral shear force 1.4 ± 0.3 mm and 2.0° ± 0.5°, and for compression

ISSN:0736-0266    

DOI:10.1002/jor.1100040203

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

年代:1986

数据来源: WILEY

摘要:

AbstractReconstruction of the anterior cruciate ligament (ACL) with patellar tendon (PT) is a common procedure for the symptomatic ACL‐deficient knee. Questions regarding graft incorporation, viability, and nutrition of the transplanted tissue are of concern. This relates to the graft's response to its new intrasynovial milieu and new physical forces. These factors were studied in a rabbit model of ACL reconstruction using PT and were evaluated with histological and biochemical parameters with respect to time. A histological and biochemical metamorphosis of the grafted PT occurred in this study. Autografts demonstrated a gradual assumption of the microscopic properties of normal ACL; by 30 weeks postoperatively, cell morphology was ligamentous in appearance. Normally, type III collagen is not observed in PT, however, a gradual increase in its concentration was seen in the grafts; by 30 weeks its concentration (10%) was the same as in normal ACL. Similarly, glycosaminoglycans content increased from its normally low level in PT to that found in native ACL. Collagen‐reducible crosslink analysis demonstrated that grafted tissue changed from the normal PT pattern of low dihydroxylysinonorleucine (DHLNL) and high histidinohydroxymerodesmosine (HHMD) to the pattern seen in normal ACL (high DHLNL and low HHMD) by 30 weeks. These data suggest that when PT is placed in the anatomic and environmental milieu of the ACL, a “ligamentization” of the grafted tissue results; also the autograft initially depends on synovial fluid nutrition, as revascularization occurs after

ISSN:0736-0266    

DOI:10.1002/jor.1100040204

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe present study addresses the relationship between vascular reorganization and the biomechanical changes occurring during canine long bone fracture healing. A middiaphyseal osteotomy of the radius was performed, and angiographic studies were carried out using India ink injections from 2 to 12 weeks postosteotomy. The radii were harvested, subjected to nondestructive four‐point bend testing on an Instron, and then sectioned and cleared according to the Spaltholtz technique. The observed microangiographic patterns were correlated with the calculated rigidity values. Quantitative bone blood flow measurements around the osteotomy were performed on a different group of animals, using the radiotracer microsphere technique, at 3, 6, and 9 weeks postosteotomy to correlate with our qualitative microangiographic results. We demonstrated a direct and predictable relationship between the phase of vascular reorganization and the rigidity. This correlation was present even in our delayed union specimen

ISSN:0736-0266    

DOI:10.1002/jor.1100040205

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

年代:1986

数据来源: WILEY

摘要:

AbstractTechnetium‐99m methylene diphosphonate ([99mTc]MDP) is the most widely used bone‐scanning agent today. In order to determine the precise bone locus of99mTc corresponding to the delayed bone scan image, and to test the potential clinical use of this agent in enhancing the information obtained by bone scan, we employed [99mTc]MDP in this microautoradiographic study of normal bone and bone repairative tissue. Four white rabbits underwent operations in which two 1.5‐mm drill holes were created in the subtrochanteric regions of both of their femora. An additional four white rabbits underwent sham operations of their femora, in which neither drilling nor periosteal injury occurred. Two rabbits were controls and did not undergo operation. After 7 days, the first two groups of rabbits were injected with [99mTc]MDP and bone scanned 2 h later. After the scans were completed, all three groups of animals were killed and their femora histologically processed for microautoradiography and routine histopathology. In the two groups that were injected with [99mTc]MDP, all bones showed the isotope to be clearly localized along mineralization fronts. The isotope was occasionally found in the substance of the osteoid, but was absent from the cytoplasm and nuclei of osteoblasts and osteocytes. Osteocytic lacunae showed the presence of isotope at their borders, but no identifiable pattern of isotope uptake was noted. Neither osteoclasts nor Howships lacunae showed isotope uptake. The animals that received drill holes showed corresponding areas of uptake by bone scan, whereas those that did not receive drill holes showed no bone scan activity at these sites. The histological findings were qualitatively similar in the bones from both groups of animals, but were quantitatively greater in the bones undergoing repair. The uninjected animals showed no positive chemography on their slides, indicating that the histological fixing and embedding solutions did not introduce artifacts into the technique. Skeletal scintigraphy has been shown to be a valuable clinical tool in the assessment of pathological conditions of bone. Through the use of microautoradiography, a correlation between the information gained by a bone scan and that of a bone biopsy or excised bony lesion can be made. This may aid in the assessment of the biological behavior of tumors or other pathological conditions of bone, as well as the precision of the bone scan in defining or localizing an osseous l

ISSN:0736-0266    

DOI:10.1002/jor.1100040206

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

年代:1986

数据来源: WILEY

摘要:

AbstractMouse calvaria were maintained in organ culture without serum additives. The effects of three gold complexes—aurothioglucose, aurothiomalate, and auranofin—on active bone resorption (45Ca release) and hydroxyproline synthesis were determined. The influence of these compounds on DNA and protein synthesis and lysosomal enzyme release from calvaria was also assessed. All gold complexes reduced bone resorption to some extent, with auranofin being the most potent within a narrow concentration range (10−6M). This concentration of auranofin also significantly inhibited collagen synthesis, although DNA and protein synthesis were unaffected. None of the compounds tested appeared to mediate their action via significant inhibition of lysosmal enzyme re

ISSN:0736-0266    

DOI:10.1002/jor.1100040207

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

年代:1986

数据来源: WILEY

摘要:

AbstractA dividable titanium implant was inserted in the tibial metaphysis of rabbits, which permitted a numerical evaluation of ingrowing bone. The implant on the test side was used as cathode and was connected to a subcutaneously located stimulator delivering constant current of either 5 μA, 20 μA, or 50 μA. A corresponding control implant was inserted in the other tibia of the same animal and treated likewise, but was not connected to the stimulator. Distally to each implant, a platinum‐iridium screw was inserted into the cortex and connected on the test side to the stimulator to serve as the anode. The results showed a 2.4‐fold increase in bone formation with 5 μA. In the 20‐μA group, there was 2.6‐fold more bone in the test chambers. Direct current (DC) stimulation with 50 μA caused a clear decrease of bone volume, with an average of 48% less bone in the test implants. The results indicate that 5 and 20 μA direct current enhance bone ingrowth into a titanium implant that is used as a cathode. The osteogenesis seemed to be more pronounced in the case where the chamber was used as a cathode compared to earlier experiments in which the cathode was placed at a distance of 5 mm fr

ISSN:0736-0266    

DOI:10.1002/jor.1100040208

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

年代:1986

数据来源: WILEY

摘要:

AbstractThis study used phosphorous nuclear magnetic resonance (31P‐NMR) spectroscopy to examine the metabolic demand resulting from electrical muscle stimulation (EMS) applied to human skeletal muscle. For each of six subjects, the forearm flexor muscle group was monitored with31P‐NMR during both maximum voluntary and 6‐s EMS‐induced contractions. A simple protocol using a tourniquet was added in one subject to assess the role of blood flow in this model. Eight hertz (nontetanic) EMS showed less (p<0.025) depletion of phosphocreatine (36%) than did tetanic 70‐Hz EMS (60%), voluntary isometric (66%), and voluntary isokinetic (68%). The results of the tourniquet studies suggested that the nontetanic EMS allowed relatively increased muscle blood flow and oxygen supply during contraction. Tetanic EMS provided a similar metabolic demand to that of conventional resistive exercise, as measured by31P‐NMR s

ISSN:0736-0266    

DOI:10.1002/jor.1100040209

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

年代:1986

数据来源: WILEY

摘要:

AbstractSequential histomorphometric studies on the developing rabbit tibia from birth to skeletal maturity demonstrate that growth plate height lessens as longitudinal growth diminishes. Differing rates of development proximally and distally are documented. Distally, growth plate height, width, and area and total epiphyseal area peak or reach near maximum values by 3 weeks, whereas proximally, they do so by 8 weeks (except for height, which also peaks at 3 weeks). The distal growth plate is being obliterated by 16 weeks, at which time the proximal growth plate remains well structured and open. The distal tibia and fibula develop as one tissue mass. The articular cartilage and epiphyseal cartilage are continuous from birth, whereas a single ossification center and a single growth plate are present by 8 weeks. The data point to the presence of intrinsic growth plate, as well as systemic, control mechanisms affecting skeletal growth. Knowledge of temporal and quantitative features of epiphyseal and growth plate development will greatly aid in the elucidation of the underlying controls.

ISSN:0736-0266    

DOI:10.1002/jor.1100040210

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

年代:1986

数据来源: WILEY