Showing papers in "Journal of Orthopaedic Research in 1989"

TL;DR: The results demonstrate that with the subjects walking at their natural or preferred spped, the gait variables are quite repeatable, and suggest that it may be reasonable to base significant clinical decisions on the results of a single gait evaluation.

TL;DR: This study provides a framework for identifying both the physical and biological mechanisms by which dynamic compression can modulate chondrocyte biosynthesis and potentially allows in vitro evaluation of clinical strategies of continuous passive motion therapy to stimulate cartilage remodeling.

TL;DR: Using the knee joints of New Zealand White rabbits, a baseline study was made to determine the intrinsic capability of cartilage for healing defects that do not fracture the subchondral plate and the effect of autologous chondrocytes grown in vitro on the healing rate of these defects.

TL;DR: The intrinsic compressive and tensile properties of normal bovine medial menisci were measured, and the variations in these properties with respect to the structural organization of the tissue and test specimen location were examined.

TL;DR: The results suggest that a combination of porous ceramics and marrow cells may be useful for clinical problems requiring osseous reconstruction.

TL;DR: The combination of moments in joint angles during chair‐rising are unique among common activities of daily living and should be considered in chair selection as well as in the guidelines for prosthetic devices.

TL;DR: Articular geometry of the tibia has been studied in relation to the functional axis and extra‐articular bone landmarks, using a Cartesian coordinate system, relevant to the kinematics of the lower limb, design and sizing of resurfacing components, and possibly to the pathogenesis of osteoarthritis.

TL;DR: In immobilized cartilage, failure of the newly synthesized proteoglycans to bind to hyaluronate is not a mechanism of accelerated proteoglycan loss, and the acceleratedroteoglycan turnover appears to be caused by a combination of decreased synthesis and increased proteolysis of the secreted proteoglyCans.

TL;DR: The results indicate that retaining vascularity does not prevent significant reduction in graft properties that occur postoperatively, nor does it accelerate the return in strength and stiffness, which returns earlier than maximum force and joint anteroposterior (AP) force displacement data.

TL;DR: To assess the degree of success of anterior cruciate ligament (ACL) replacement using the patellar tendon (PT) autograft, 29 New Zealand white rabbits underwent ACL reconstruction using a medial one‐third PT autografted.

TL;DR: The postoperative hypernickelemia and nickeluresis may reflect contamination of the operative field with Ni‐containing particles from the drills, cutting jig, and drilling jigs, or it may represent a previously unrecognized pathophysiological response to surgery.

TL;DR: The data indicate that adult bovine articular chondrocytes possess the capacity to augment both mitotic and differentiated cell functions in response to growth factors and suggest that, with the exception of insulin and Sm‐C/IGF‐I, these factors produce their cellular effects via different receptor or postreceptor pathways.

TL;DR: The ligamentum flavum did not appear to be a significant factor for the dynamic changes affecting the dimensions of the canal even after the disk had been excised in order to produce a total collapse of the disk space.

TL;DR: Critical pressure levels for compressioninduced occlusion of the arterioles, capillaries, and venules of the intrinsic vasculature of the nerve roots were determined and an intraneural edema developed in nerve roots exposed to compression for 2 h.

TL;DR: A method to produce and test mechanically microspecimens of trabecular and cortical tissue from human iliac crests, and compare their measured moduli was designed and a significant difference according to a two‐way analysis of variance was found.

TL;DR: The human ACL was found to be a primary restraint to anterior tibial displacement at both 90° and 30° of flexion, and the patellar tendon, when used as an ACL replacement in the dog and primate, exhibited significant loss in structural mechanical and material properties early after implantation.

TL;DR: There should be a relationship between hardness and Young's modulus, and evidence suggests that the yield stress of cancellous bone is similar to that of adjacent compact bone.

TL;DR: The collagen waviness known as a crimping was found to occur in ACL and PT fascicles, and its amplitude seems to decrease from the periphery toward the fascicular center.

TL;DR: It is hypothesize that the inward bulging causes radial tensile stresses within the disc, leading to disruption of adjacent layers of annulus, which is responsible for outward bulging of the disc surface.

TL;DR: Predictions about the relative and the real time duration of cellular events during vascular invasion are made, including an analysis of the time sequence of death of the terminal hypertrophic chondrocyte.

TL;DR: Results indicate that the cryopreservation protocol used did not have an effect that the authors could measure on these specific mechanical behaviors of articular cartilage and no statistical differences in the mechanical behaviors measured from the limit cycle or in cartilage thickness were revealed.

TL;DR: To measure contact pressure in the human P‐F joint during impact loading on the isolated, flexed knee, experiments were conducted by serially increasing the impactor velocity in repeated tests until bone fracture was observed.

TL;DR: The taped‐on electrogonerometer, when compared with the pinned electrogoniometer, was adequate for calculating the predominant frequency componenet and spread of spectral data, but overestimated the magnitudes of the maximum spectral density and total area of the spectral curves.

TL;DR: A rabbit model for anterior cruciate ligament (ACL) reconstruction using autogenous patellar tendon was utilized to study the early events of autograft cellular dynamics.

TL;DR: The zones of further ossification, bone bridging, and bone consolidation predicted in the present study were found to be similar to the Ossification patterns that have been documented by other researchers.

TL;DR: The results indicate that skin over muscle tolerates greater locally applied loads and deformations because the pressure is lower within the tissue than when similar loads and deformation are applied to skin over bone.

TL;DR: Evaluation of the internal and external morphology of the vertebral pedicles revealed that adequate bone stock is generally available at T2, T7, T12, and L1–L5 spinal levels to accept screws in the 4–7‐mm diameter range, and extreme care must be exercised to prevent bending of the pedicle screws during implantation.

TL;DR: Human trabecular bone specimens from the proximal tibial epiphysis of nine macroscopically normal cadaver knees were tested nondestructively to a fixed strain for analysis of unloading energy and hysteresis energy followed by a destructive test for analysisof work to failure.

TL;DR: Fung's quasilinear theory can be used to describe the stress relaxation response over the range of strains examined when a nonlinear regression is performed to determine an “average” normalized relaxation function.

TL;DR: The axial rotation (rotation about a vertical axis) of the vertebrae, of the ribs, and of the back surface are components of the deformity recognized clinically as the “rib hump” in thoracic scoliosis.