ISSN:0736-0266    

DOI:10.1002/jor.1100010301

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

年代:1983

数据来源: WILEY

摘要:

AbstractIn mature dogs with comparable levels of bone remodeling, we produced either increased (with adenosine triphosphate) or decreased (with epinephrine) blood flow to one hindlimb. In 13 dogs (five control, four with increased flow, and four with decreased flow), we compared uptake, at 3 h after injection of radiolabeled diphosphonate in the mid‐tibia, with blood flow as determined by microspheres. Blood flow was determined with85Sr‐labeled microspheres, and determination of uptake of99mTc methylene diphosphonate (99mTc‐MDP) was by a gamma detector. There was a linear relationship between changes in diphosphonate uptake and changes in blood flow at decreased and normal flows; however, at high flows the relationship was nonproportional, indicating a disproportionately slower increase in99mTc‐MDP uptake with increasing blood flow. In six dogs an initial 1‐h uptake curve of99mTc‐MDP was determined in both control and experimental limbs under states of increased and decreased blood flow. The 30‐min uptake value, 60‐min uptake value, area under the curve, and the slope of the curve were related to flow as determined by microspheres. The data are consistent with the hypothesis that deposition of bone‐concentrating isotopes such as99mTc‐MDP is partly controlled by blood flow; at subnormal and normal flows tracer uptake is closely related to blood flow, but at supranormal flow rates it is not and appears to b

ISSN:0736-0266    

DOI:10.1002/jor.1100010302

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

年代:1983

数据来源: WILEY

摘要:

AbstractThis study was undertaken to determine the effect of loading rate on bone failure under singular and combined loading states. Using the entire loading range of an Instron Materials Testing Machine, 190 pairs of canine radii were tested. One bone of each pair was subjected to either torsional or a combination of axial and torsional loads, and compared with a control specimen. Compressive loads of 4.6 and 11.5 N were utilized. Torque to failure and energy data versus loading rate were plotted. As loading rate increased, the torque and energy values were found to increase, reach a peak, and then decline at higher rates. Fractures produced under the combined state of loading are representative of those clinically found in human trauma situations.

ISSN:0736-0266    

DOI:10.1002/jor.1100010303

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

年代:1983

数据来源: WILEY

摘要:

AbstractThere has been considerable controversy concerning the capacity of tendons to heal intrinsically without adhesion formation. To help clarify this issue, a tissue culture model was developed to study the potential of tendon fibroblasts to proliferate and migrate. Avian flexor tendons, isolated free of sheath and all synovial components, were maintained in sterile culture plates with Dulbecco's Modified Eagle Medium. After 5 days in culture, the 2 mm tendon biopsies were analyzed for DNA synthesis ([125I]iododeoxyuridine incorporation) and migration of fibroblasts out of the explant (planimeter analysis). DNA synthesis was maximal on day 5 in culture, and tendon fibroblasts were observed migrating from the biopsy within 48 h. Addition of cells from plasma resulted in a significant increase in fibroblast migration, and the presence of fibrin in the plasma clot was an absolute requirement for the migratory process. These findings further support the hypothesis that injured tendons can heal by an intrinsic healing process in addition to healing by adhesion formation.

ISSN:0736-0266    

DOI:10.1002/jor.1100010304

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to compare selected rabbit tendons and ligaments morphologically and biochemically. Five representative structures from each of six age‐ and sex‐matched rabbits were compared. Biochemical analyses included total collagen, reducible collagen cross‐links, quantitative collagen typing, DNA, and glycosaminoglycans. Histological and chemical differences were demonstrated between the tendons and the ligaments. Smaller differences were also found between the individual ligaments (collateral and cruciate) and between the two tendons (patellar and Achilles) that were examined. These findings suggest that ligaments are more metabolically active than tendons, having more plump cellular nuclei, higher DNA content, larger amounts of reducible cross‐links, and the presence of more type III collagen, as compared with tendons. They also contain slightly less total collagen than tendons and more glycosaminoglycans. We conclude that the tendons and ligaments studied have unique histological and biochemical characteristics, despite their gross similarities. Relatively increased metabolic activity in ligaments, implied by our findings, may be species specific, age related (transient), or may truly represent a structural expression of functional need for more rapid adaptation. Further investigation of other similarities or differences between particular ligaments (or tendons) is indicated, and attention is directed toward the importance of such variables in development of models for tendon and ligament

ISSN:0736-0266    

DOI:10.1002/jor.1100010305

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

年代:1983

数据来源: WILEY

摘要:

AbstractSeveral factors influencing the myoelectric activity of muscles surrounding the knee joint were studied using fine‐wire monopolar electrodes. The muscles studied included the vastus lateralis, vastus intermedius, rectus femoris, vastus medialis, gracilis, sartorius, biceps femoris, semimembranosus, semitendinosus, tensor fasciae latae, medial head of the gastrocnemius, and lateral head of the gastrocnemius. Muscle activity was measured in response to unidirectional loads tending to flex and extend the knee, and to combined loads of flexion‐adduction, flexion‐abduction, extension‐adduction, and extension‐abduction. Results indicate that the individual muscle responses are dependent upon the direction, magnitude, and combination of external moments, as well as on the flexion angle of the knee joint. Muscle response appeared to be influenced by certain intrinsic mechanical characteristics of the knee joint that tend to change the moment arms of the muscles as the knee moves. For example, the substantial changes in quadriceps myoelectric activity with knee flexion, with constant load applied, can be related to the movement of the tibial‐femoral contact changing the lever arm of the quadriceps mechanism. This study indicates that the mechanics of the knee joint must be taken into consideration while attempting to interpret or predict the load response of muscles crossing the

ISSN:0736-0266    

DOI:10.1002/jor.1100010306

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

年代:1983

数据来源: WILEY

摘要:

AbstractSeventeen postoperative total knee arthroplasty (TKA) patients were evaluated using two tests of knee joint position sense. Young controls and age‐matched controls underwent identical tests. The TKA patients also underwent gait analysis, including foot switch stride analysis, and clinical evaluation using a standard scoring system. Results showed statistically significant decreases in joint position sense from young controls to old controls, and further significant decreases with joint disease; however, no further worsening was noted as a result of TKA. The abnormal gait parameters seen in TKA patients correlated as well with position sense as with clinical score. Strongest correlations were seen when a combined clinical and proprioceptive score was compared with gait parameters. In spite of alleviation of pain and correction of deformity, normal gait and function are not typically achieved after total knee replacement. Irreversible loss of joint proprioceptive function due to the disease process may be a major factor in the discrepancy between clinical and functional outcomes of total joint arthroplasty. Furthermore, loss of proprioception and the resulting abnormal gait patterns may place increased stress on components and contribute to loosening. In addition, an association between degenerative joint disease and decline in proprioception is suggeste

ISSN:0736-0266    

DOI:10.1002/jor.1100010307

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe objective of this study was to develop an apparatus for reliable, reproducible, and minimally invasive measurements of long‐term, myoneural function. Twenty conditioned dogs were anesthetized and placed supine with one hindlimb secured in a boot apparatus. The hindpaw was attached to a force transducer that was connected to a recorder for continuous monitoring of torque. Muscles within the anterolateral compartment were stimulated by percutaneous electrodes over the peroneal nerve near the fibular head. This elicited isometric dorsiflexion of the hindpaw. Twitch and tetanic torques correlated positively with dog weight whereas other skeletal‐muscle function parameters (time to peak tension, one‐half relaxation time, and endurance) were independent of dog weight. Muscle function results were consistent with an overall compartmental composition of 30% Type I and 70% Type II fibers. Repetitive testing of twitch and tetanic torques in the dog legs yielded coefficients of variance of 3–4% (intraday) and 7% (interday). Thus, about onehalf of the interday variability may be accounted for by diet, exercise, and other physiological conditions that change daily. The apparatus was also used to detect myoneural degeneration following tourniquet ischemia. The results indicate that this procedure for evaluating muscle function yields reliable and quantitative results noninvasively, and thus allows long‐term testing of muscle function in normal and diseased hindlimb

ISSN:0736-0266    

DOI:10.1002/jor.1100010308

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe longitudinal compressive load acting on the L3–L4 spinal motion segment was investigated during normal level walking for a range of speeds of progression. Forces were predicted using experimental data from photogrammetric measurements of upper body segmental motion and inertial properties, along with a biomechanical model of the trunk. A partial validation of the results was obtained using records of the electrical activity of the trunk muscles and intradiscal pressure information available in the literature. Experiments were carried out in five normal young male subjects. Results showed that the L3–L4 motion segment is subjected to cyclic compressive loads. The maximum and minimum values of this load vary with walking speed from approximately 1.0 to 2.5 and from 0.8 to 0.2 times body weight, respectively. Relevant peaks occur with a frequency ranging approximately from 1.3 to 2.5 Hz. Muscular action is mostly concentrated in the trunk extensors, which show a burst of activity at the time of ipsilateral toe

ISSN:0736-0266    

DOI:10.1002/jor.1100010309

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe histopathologic characteristics,in vitroproteoglycan and glycosaminoglycan biosynthesis, and proteoglycan content of osteoarthritic (OA) cartilage tissue types from human femoral heads obtained at the time of total joint replacement were compared. Articular cartilage from fibrillated or discolored cartilage surfaces demonstrated overlapping histopathologic patterns, while cartilage from osteophytic areas was distinct.35SO4from each of these three tissue types was found in two peaks of radioactivity on a Sepharose CL‐2B column. The average partition coefficient (Kav) of the first peak (peak I) was 0.07, while that of the second (peak II) was 0.63. Proteoglycan monomer predominated in discolored, fibrillated, and osteophytic OA cartilage in peak I. The hydrodynamic size on Sepharose CL‐2B of the synthetic proteoglycan monomer was the same for discolored, fibrillated, and osteophytic samples (Kav, 0.25–0.28). Discolored and fibrillated tissues showed a similar percentage of proteoglycan monomer in peak II, whereas osteophyte was reduced in proteoglycan monomer content in peak II. In addition, the endogenous proteoglycans extracted from each cartilage area were generally of a smaller hydrodynamic size than the newly synthesized peak I or proteoglycan monomer. Glycosaminoglycans were predominantly chondroitin 6‐sulfate. These results indicated that OA discolored and fibrillated cartilage tissue types from defined topographical areas of human femoral heads possessed neither unique histopathologic nor synthetic or endogenous proteoglycan characteristics. Osteophytic cartilage appeared more histopathologically distinct than either discolored or fibrillated OA cartilage, but synthesized proteoglycan monomer with similar hydrodynamic size to the other cartilage tissu

ISSN:0736-0266    

DOI:10.1002/jor.1100010310

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

年代:1983

数据来源: WILEY