Showing papers in "Journal of Orthopaedic Research in 1995"

TL;DR: The overall risk of injury to the ligament from varus or valgus moment applied in combination with internal tibial torque is similar to the risk from internal tIBial torque alone.

TL;DR: The hypothesis that deformation of chondrocytes or a change in their volume may occur during in vivo joint loading and may have a role in the mechanical signal transduction pathway of articular cartilage is supported.

TL;DR: It is concluded that the trabecular adaptation to mechanical load, as described by Wolff, can be explained by a relatively simple regulatory model and is useful for investigating the effects of physiological parameters on the development, maintenance, and adaptation of bone.

TL;DR: It is suggested that bone morphogenetic proteins 2 and 4 are important regulators of cell differentiation during fracture repair, despite the fact that they are the most potent osteoinductive proteins known.

TL;DR: It is demonstrated that articular chondrocyte metabolism responds directly to physical stimulation in vitro and suggests that mechanical loading may directly influence cartilage homeostasis in vivo.

TL;DR: Results indicate that platelet‐supplemented medium stimulates proliferation and maintains the differentiated function of human osteoblast‐like cells.

TL;DR: TiAlV particles appeared to be the most competent to elicit the synthesis and release of inflammatory mediators in human monocytes, albeit at a lower level, whereas the particles of polyethylene retrieved from interfacial membranes were less stimulatory in these short‐term in vitro experiments.

TL;DR: The anterior portion of the supraspinatus tendon is mechanically stronger than the other portions, and it seems to perform the main functional role of the tendon.

TL;DR: The structure and histopathology of the insertional region in 50 tendons from cadavers, including Achilles tendon inserts onto the calcaneus, and the retrocalcaneal bursa intervenes between it and the bone immediately proximal to the enthesis, were examined.

TL;DR: These analyses demonstrate how changes in motion segment stiffness, muscle activation strategy, or muscle stiffness (due to degenerative changes, injuries, fatigue, and so on) might lead to spinal instability and “self‐injury”.

TL;DR: It is demonstrated that growth factors can stimulate cell division in ligaments and may be effective in enhancing ligament healing but that these differences were not great enough to explain fully the clinical differences observed between healing of the medial collateral and anterior cruciate ligaments.

TL;DR: It is suggested that force attenuation in trochanteric soft tissues alone is insufficient to prevent hip fracture in falls in which an elderly person lands directly on the hip, and additional energy‐absorbing mechanisms are likely to be involved if fracture does not occur.

TL;DR: This in vitro model may represent a valid system with which to test the effects of various stress conditions on the tensile properties of tissues and appears to be dependent on the presence of a viable cell population.

TL;DR: The effect of load on incorporation rates in the disc is compatible with the suggestion that rates are at a maximum at in vivo hydrations and decrease if the hydration decreases or if the disc swells.

TL;DR: The observed changes in material properties demonstrate that relatively short periods of joint instability result in significant changes in the flow‐independent viscoelastic behavior of articular cartilage, as well as in the intrinsic stiffnesses in compression and shear.

TL;DR: It is proposed that this phenomenon is the equivalent of a stress fracture and that its biological and mechanical elements are significant in the etiology of stress fractures.

TL;DR: Muscles in which transformations had ceased displayed, on average, a significantly higher percentage of fast type‐IIB fibers than were found in muscles with ongoing transformations, which strongly indicates that the transformations proceeded in the direction from “slow oxidative to “fast glycolytic”.

TL;DR: An experimental system was developed that allows direct measurement of friction at the tendon‐pulley interface, and the results were interpreted by use of a theoretical model for friction of a cable around a fixed pulley.

TL;DR: Dose‐dependent reductions in the mechanical properties and material properties were found, and significant decreases in hydroxypyridinium crosslink density with 6 Mrad of irradiation were found; other possible mechanisms also are being explored to more fully explain these dose‐dependent changes.

TL;DR: A new technique, termed texture correlation, is described for the measurement of displacement and strain patterns within samples of trabecular bone, a modification of digital image correlation, a method for analysis of deformation in objects marked with random surface speckle.

TL;DR: Examining the trade‐off between restoring range of motion and maintaining plantar flexion strength after surgical treatment for contracture of the triceps surae indicates that independent lengthening of the contracted gastrocnemius and soleus may be a more effective means to restore range ofmotion and maintain plantarflexion strength when combined contractures of the gastrocNemiusand soleus is present.

TL;DR: Reduced crosslink density in collagen in scar tissue may offer a more specific explanation for the mechanical inferiority, in the rabbit, of healing medial collateral ligaments compared with normal ligaments over time.

TL;DR: Results indicate that cytoskeletal changes may be an integral part of the response of chondrocytes to hydrostatic pressure, and suggest that microfilaments are more vulnerable to pressure than vinculin.

TL;DR: The results indicate that the patella may be unstable in the first phase of knee flexion when the tibia is rotated, and it is likely that the anatomic configuration of thepatella allows the patela to seat in a stable configuration so that it resists moderate changes in the load and direction of the quadriceps.

TL;DR: The osteoarthritic process may damage the matrix in the superficial layer and induce changes leading to the expression of the hypertrophic chondrocyte phenotype, which is surprising since that region of the cartilage does not calcify and one of the proposed roles of type‐X collagen is in mineralization.

TL;DR: The objective of this study was to quantify the strength of the repair tissue that forms at the interface between pairs of cartilage explants maintained in apposition in an in vitro culture system and to identify the repair process appeared to be dependent on viable cells.

TL;DR: The data suggest that regional differences (peripheral compared with central) in responsiveness to human, recombinant platelet‐derived growth factor‐AB may reflect a different level of signal transduction machinery for growth factor receptors and distinct fibrochondrocyte populations.

TL;DR: The posterior cruciate ligament was found to be widest in the medial‐lateral direction, whereas the anterior cruciates ligament usually was larger in the anterior‐posterior direction.

TL;DR: Investigation of the recruitment and co‐contraction of lumbar muscles during the voluntary development of slowly and rapidly varying trunk flexion and extension, lateral bending, and axial twisting moments suggests that substantial contractions of lumblingar muscles are used for reasons other than equilibrating moments at the L3‐L4 level.

TL;DR: Human cartilage oligomeric matrix protein was purified in a native form from normal adult human articular cartilage and demonstrated a bouquet‐like five‐armed structure, with peripheral globular domains connected by thin flexible strands to a central assembly domain.