Identification of Cross-Sectional Parameters of Lateral Meniscal Allografts That Predict Tibial Contact Pressure in Human Cadaveric Knees

2002 ◽  
Vol 124 (5) ◽  
pp. 481-489 ◽  
Author(s):  
Arthur Huang ◽  
M. L. Hull ◽  
Stephen M. Howell ◽  
Tammy Haut Donahue
Keyword(s):  
Contact Pressure ◽  
Contact Area ◽  
Articular Surface ◽  
Maximum Pressure ◽  
Cross Sectional ◽  
Meniscal Allograft ◽  
Sensitive Film ◽  
Mean Pressure ◽  
Pressure Sensitive Film ◽  
Sectional Parameters

To guide the development of improved procedures for selecting meniscal allografts, the objective of this study was to identify which cross-sectional parameters of a lateral meniscal allograft predict the contact pressure of the articular surface of the tibia. To meet the objective, the contact pressure of the articular surface of the tibia was measured with a lateral meniscal autograft and a lateral meniscal allograft using pressure sensitive film in 15 fresh-frozen human cadaveric knees. Allografts were matched only in transverse dimensions to the autograft but not in cross-sectional dimensions. Knees were loaded to 1200 N in compression at flexion angles of 0, 15, 30 and 45 degrees using a load application system that allowed unconstrained motion in the remaining degrees of freedom. Five cross-sectional parameters for both of the grafts in each of the anterior, middle, and posterior regions were derived from measurements obtained using a laser-based non-contacting three-dimensional coordinate digitizing system (3-DCDS) (Haut et al., J. Orthop Res, 2000). Five contact variables (i.e. the maximum pressure, mean pressure, contact area, and anterior-posterior and medial-lateral locations of the centroid of contact area) were determined from the pressure sensitive film. When each allograft was paired with the corresponding autograft, the root mean squared percent differences for the cross-sectional parameters ranged from a minimum of 28% for the width of the posterior region to 572% for the height of the posterior region. The root mean squared percent differences between the contact variables for paired grafts were 29% for the maximum pressure, 19% for the mean pressure, and 24% for the contact area. Differences in the cross-sectional parameters between the grafts were related to differences in the contact variables using regression analysis. Difference in the width was most often a predictor variable in the regression models with R2 values ⩾0.45. Differences in all of the four remaining cross-sectional parameters were also important predictor variables. Because failure to match cross-sectional parameters causes substantial difference in contact variables between an allograft and autograft and because cross-sectional parameters predict the contact pressure on the tibial plateau, protocols used to prospectively select allografts should concentrate on matching cross-sectional parameters and particularly the width to those of the original meniscus.

Contact Mechanics of the Medial Tibial Plateau after Implantation of a Medial Meniscal Allograft

2000 ◽  
Vol 28 (3) ◽  
pp. 370-376 ◽  
Author(s):  
Mohammad M. Alhalki ◽  
Maury L. Hull ◽  
Stephen M. Howell
Keyword(s):  
Contact Mechanics ◽  
Tibial Plateau ◽  
Outer Edge ◽  
Maximum Pressure ◽  
Medial Tibial Plateau ◽  
Normal Contact ◽  
Meniscal Allograft ◽  
Sensitive Film ◽  
Mean Pressure ◽  
Pressure Sensitive Film

The goal of this study was to determine how well a medial meniscal allograft restores the normal contact mechanics of the medial tibial plateau at the time of implantation. We measured maximum pressure, mean pressure, and contact area of the intact human cadaveric knee, the knee after meniscectomy, the knee with the original meniscus removed and reimplanted as an autograft, and the knee with an allograft. Measurements were made using pressure-sensitive film in 10 specimens loaded in compression to 1000 N at 0°, 15°, 30°, and 45° of flexion. The autograft and the allograft were identically implanted by cementing bone plugs attached to the meniscal horns in anatomic transtibial tunnels and suturing the outer edge of the meniscus to the remnant of the original meniscus. A medial meniscal allograft did not consistently restore normal contact mechanics because the process of implantation and the degree of match between the original and allograft meniscus affected the immediate load-bearing performance of the transplant. However, the allograft did significantly reduce the contact pressure compared with the knee after meniscectomy. If the results from this study can be extrapolated to patients, then using an allograft to restore contact mechanics to normal may require improvements in surgical technique and graft selection.

Measurement of Contact Pressure in Metal Forming by Pressure Sensitive Film

1984 ◽  
Vol 106 (2) ◽  
pp. 127-131 ◽  
Author(s):  
K. Mori ◽  
K. Osakada ◽  
M. Fukuda
Keyword(s):  
Contact Pressure ◽  
Metal Forming ◽  
Maximum Pressure ◽  
Rigid Plastic ◽  
Workpiece Material ◽  
Simple Method ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Color Density ◽  
Pressure Sensitive Film

A simple method is presented for measuring the distribution of tool contact pressure in metal forming by using a pressure sensitive film which detects the contact pressure from the change in color density. In the method, a sufficiently hard sheet metal compared to the workpiece is inserted between the workpiece and the pressure sensitive film in order to eliminate the influence of frictional shear stress at the tool-workpiece interface on the measured result. Since the maximum pressure which can be determined by the film is 150MPa, lead is used as a workpiece material. Distributions of tool contact pressure are measured in upsetting of cylindrical billets, in free forging of plates of various shapes, and also in backward extrusion of a can. The measured distributions agree well with those computed by the rigid-plastic finite element method.

Contact Stress and Linearized Modal Predictions of As-Built Preloaded Assembly

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Adam R. Brink ◽  
Robert J. Kuether ◽  
Matthew D. Fronk ◽  
Bryan L. Witt ◽  
Brendan L. Nation
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Contact Area ◽  
Element Model ◽  
High Fidelity ◽  
Vibration Modes ◽  
Low Level ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Pressure Sensitive Film

Abstract The member stiffness and pressure distribution in a bolted joint is significantly influenced by the contact area of the mechanical interface under a prescribed preload force. This research explores the influence of as-built surface profiles for nominally flat interfaces of a C-Beam assembly with two well-defined contact regions. A high-fidelity finite element model is created such that the model uncertainty is minimized by updating and calibrating the piece parts prior to the preload assembly procedure. The model is then assembled and preloaded to evaluate the contact stresses and contact area for both nominally flat and perturbed non-flat surfaces based on three-dimensional surface topography measurements. The predicted pressures are validated with digitized pressure-sensitive film measurements. The high-fidelity modeling reveals how the compliance and thickness of the pressure-sensitive film alter the measured pressures, leading to incorrect evaluations of the stresses and contact area in the joint. The resulting low-level dynamic behavior of the preloaded assembly is shown to be sensitive to the true contact area by linearizing the nonlinear finite element model about the preloaded equilibrium and performing a computational modal analysis. The resonant frequencies are validated with experimental measurements to demonstrate the effect of the contact area on the modal characteristics of the bolted assembly. Vibration modes and loading patterns exhibit varying levels of sensitivity to the contact area in the joint, leading to an improved physical understanding of the influence of contact mechanics on the low-level linear vibration modes of jointed assemblies.

Assessment of Nominal Contact Area Parameters by Means of Ultrasonic Waves

2004 ◽  
Vol 126 (4) ◽  
pp. 639-645 ◽  
Author(s):  
Francesco Aymerich ◽  
Massimiliano Pau
Keyword(s):  
Contact Area ◽  
Ultrasonic Method ◽  
Ultrasonic Waves ◽  
Contact Interface ◽  
Ultrasonic Beam ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Pressure Sensitive Film ◽  
Blurring Effect ◽  
Nominal Contact Area

In this paper the application of an ultrasonic method to evaluate size and shape of the nominal contact area between two contacting bodies is studied. The technique is based on the analysis of the quota of the ultrasonic wave reflected by the interface, which may be related to the level of contact between the surfaces. A simple deconvolution procedure is applied to the raw ultrasonic data so as to remove the blurring effect introduced by the ultrasonic beam size. The ultrasonic data acquired on a simple sphere-plane contact interface are compared with those obtained by means of a commercial pressure sensitive film and the results are discussed to evaluate the capability of the ultrasonic technique to capture the main contact patch features correctly.

Bone-Plug Versus Soft Tissue Fixation of Medial Meniscal Allograft Transplants: A Biomechanical Study

2019 ◽  
Vol 47 (12) ◽  
pp. 2960-2965 ◽  
Author(s):  
Luiz Felipe Ambra ◽  
Alexandre Barbieri Mestriner ◽  
Jakob Ackermann ◽  
Amy T. Phan ◽  
Jack Farr ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Contact Pressure ◽  
Contact Area ◽  
Load Distribution ◽  
Tissue Fixation ◽  
Meniscal Allograft Transplantation ◽  
Allograft Transplantation ◽  
Meniscal Allograft ◽  
Significant Difference ◽  
Bone Plug

Background: It is controversial whether soft tissue fixation only and bone-plug techniques for medial meniscal allograft transplantation provide equivalent fixation and restoration of load distribution. Prior studies on this topic did not re-create the clinical situation with use of size-, side-, and compartment-matched meniscal transplants. Hypothesis: Both techniques will provide equivalent fixation of the meniscal transplant and restore load distribution and contact pressures similar to those of the native knee. Study Design: Controlled laboratory study. Methods: Nine fresh-frozen human cadaveric knees underwent mean contact pressure, mean contact area, and peak contact pressure evaluation in 4 medial meniscal testing conditions (native, total meniscectomy, bone-plug fixation, and soft tissue fixation) at 3 flexion angles (0°, 30°, and 60°) using Tekscan sensors under a 700-N axial load. Results: Medial meniscectomy resulted in significantly decreased contact area and increased contact pressure compared with the native condition at all flexion angles ( P < .0001). Compared with the native state, soft tissue fixation demonstrated significantly higher mean contact pressure and lower mean contact area at 0° and 30° of flexion ( P < .05), while bone-plug fixation showed no significant difference. There was no significant difference in peak contact pressure between study conditions. Conclusion: Total medial meniscectomy leads to significantly worsened load distribution within the knee. Medial meniscal allograft transplantation can restore load parameters close to those of the native condition. The bone-plug technique demonstrated improved tibiofemoral contact pressures compared with soft tissue fixation. Clinical Relevance: Medial meniscal allograft transplantation with bone-plug fixation is a viable option to restore biomechanics in patients with meniscal deficiency.

scholarly journals Evaluation of laparoscopic forceps jaw contact pressure and distribution using pressure sensitive film

2019 ◽  
Vol 24 (sup2) ◽  
pp. 105-116 ◽  
Author(s):  
Rui Zhu ◽  
Maxime Maréchal ◽  
Ikuo Yamamoto ◽  
Murray John Lawn ◽  
Takeshi Nagayasu ◽  
...  
Keyword(s):  
Contact Pressure ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Pressure Sensitive Film

Validation of a Finite Element Humeroradial Joint Model of Contact Pressure Using Fuji Pressure Sensitive Film

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Sunghwan Kim ◽  
Mark Carl Miller
Keyword(s):  
Finite Element ◽  
Contact Stress ◽  
Contact Area ◽  
Axial Loads ◽  
Contact Areas ◽  
Pressure Sensitive ◽  
Maximum Contact Stress ◽  
Sensitive Film ◽  
Pressure Sensitive Film ◽  
Maximum Contact

A finite element (FE) elbow model was developed to predict the contact stress and contact area of the native humeroradial joint. The model was validated using Fuji pressure sensitive film with cadaveric elbows for which axial loads of 50, 100, and 200 N were applied through the radial head. Maximum contact stresses ranged from 1.7 to 4.32 MPa by FE predictions and from 1.34 to 3.84 MPa by pressure sensitive film measurement while contact areas extended from 39.33 to 77.86 mm2 and 29.73 to 83.34 mm2 by FE prediction and experimental measurement, respectively. Measurements from cadaveric testing and FE predictions showed the same patterns in both the maximum contact stress and contact area, as another demonstration of agreement. While measured contact pressures and contact areas validated the FE predictions, computed maximum stresses and contact area tended to overestimate the maximum contact stress and contact area.

Ultrasonic Measurements of Contact Area and Pressure Distribution of a Pneumatic Tire on a Rigid Surface3

2008 ◽  
Vol 36 (1) ◽  
pp. 43-62 ◽  
Author(s):  
Massimiliano Pau ◽  
Bruno Leban ◽  
Antonio Baldi
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Contact Area ◽  
Ultrasonic Method ◽  
Quantitative Information ◽  
Ultrasonic Waves ◽  
Contact Pressure Distribution ◽  
Reflection Data ◽  
Novel Approach ◽  
Pressure Sensitive Film

Abstract Contact phenomena which occur at the tire-ground interface play a crucial role in most issues related to optimal performances of the vehicle, safety, comfort, and energy consumption. Thus, it is essential to have available experimental tools capable of supplying detailed information about the main contact parameters (size and shape of nominal contact area and contact pressure distribution), especially when unknown or unpredictable external conditions make it difficult to use numerical tools in assessing them. Although a number of laboratory techniques have been devised to address this problem, here we propose a novel approach that exploits the property of ultrasonic waves to be differently reflected by a contact interface depending on its stress state. This noninvasive method is capable of supplying in real-time detailed maps of contact conditions as well as quantitative information with regard to geometric features of the contact area and contact pressure distribution values after suitable postprocessing procedures. This study reports the results of the application of the ultrasonic method in the case of contact of a motor-bicycle tire on a rigid surface. A number of tests were carried out under different conditions with regard to inflation pressure and applied load. In each case, the raw reflection data were converted into graphic maps that display the contact area features and contain information about contact pressure. Moreover, to assess the quantitative reliability of the technique, ultrasonic data were compared with those obtained by means of a commercial pressure-sensitive film. The results are discussed to evaluate the capability of the ultrasonic method to correctly capture contact patch features.

Contact Area Effects on Discomfort

1994 ◽  
Vol 38 (10) ◽  
pp. 688-690 ◽  
Author(s):  
Ravindra S. Goonetilleke ◽  
Timothy J. Eng
Keyword(s):  
Surface Area ◽  
Contact Area ◽  
High Pressures ◽  
Spatial Summation ◽  
Critical Value ◽  
Critical Force ◽  
Maximum Pressure ◽  
Force Distribution ◽  
Large Area ◽  
Cross Sectional

Most “ergonomic” products attempt to adopt a uniform force distribution strategy to improve comfort. The rationale being that force distribution over a large area reduces pressure and thereby enhances user comfort. However, sensory literature alludes to the concept of spatial summation, i.e. greater sensation by stimulating a larger surface area. Hence spatial summation would tend to suggest a greater discomfort when forces are applied over large surface areas. This study reports the effect of surface area on maximum discomfort causing pressure or maximum pressure tolerance (MPT). Two circular probes of different cross sectional area were used to stimulate the skin surface. The mean MPT with a probe of 5mm diameter was 3.3 times higher than the MPT with a probe of 13mm diameter. These findings suggest the following: • Perceived discomfort and contact area seem to have a “U-relationship” above a critical force value. Traditional thinking of distributing forces is successful only in the first half of the U-curve or with forces below the critical value. The section with the monotonically increasing relationship between discomfort and contact area (i.e., second half of U) may not be seen at very low forces or forces below the critical value. • “High” pressures in concentrated areas may cause less discomfort than “moderate” pressures over a larger area. • The critical or threshold pressure to induce discomfort is force and contact area dependent.

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