Effect of Graft Height Mismatch on Contact Pressures With Osteochondral Grafting of the Talus

Background: Osteochondral allograft transplantation is technically demanding. It is not always possible to place the surface of the graft perfectly flush with the surrounding cartilage. One must often choose between placing at least some portion of the surface of the graft slightly elevated or recessed. The effect of this choice on joint contact pressure is unknown. Purpose: This study was undertaken to determine the effect of graft height mismatch on joint contact pressure in the ankle. Study Design: Controlled laboratory study. Methods: Ten human cadaveric ankles underwent osteochondral grafting by removal then replacement of an osteochondral plug. Six conditions were tested: intact, graft flush, graft elevated 1.0 mm, graft elevated 0.5 mm, graft recessed 0.5 mm, and graft recessed 1.0 mm. Joint contact pressures were measured with a Tekscan sensor while loads of 200 N, 400 N, 600 N, and 800 N were sequentially applied. Results: The peak contact pressure at the graft site for the flush condition was not significantly different from the intact condition for either medial or lateral lesions. In contrast, peak pressure on the opposite facet of the talar dome was significantly increased during the flush condition for the medial but not the lateral grafts. Elevated grafts experienced significantly increased contact pressures, whereas recessed grafts experienced significantly decreased pressures. These changes were greater for lateral than for medial lesions. Reciprocal changes in joint contact pressures were found on the opposite facet of the talus with elevated grafts on the lateral side and recessed grafts on the medial side. Conclusion: Flush graft placement can restore near-normal joint contact pressure. Elevated graft placement leads to significant increases in joint contact pressure at the graft site. Recessed graft placement leads to a transfer of pressure from the graft site to the opposite facet of the talus. Clinical Relevance: Osteochondral grafts in the talus should be placed flush if possible or else slightly recessed.

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Biomechanics of a novel extra-articular implant for younger patients with knee osteoarthritis

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2018-0050 ◽

2018 ◽

Vol 4 (1) ◽

pp. 203-205

Author(s):

Mehdi Saeidi ◽

Maziar Ramezani ◽

Piaras Kelly ◽

Mohd Sabri Hussin ◽

Thomas Neitzert

Keyword(s):

Knee Joint ◽

Cartilage Regeneration ◽

Stress Distributions ◽

Element Analysis ◽

Medial Side ◽

Pressure Distributions ◽

Joint Contact ◽

As Stress ◽

Joint Contact Pressure ◽

Contact Pressures

AbstractThis research aimed to study the efficacy of a novel implant for osteoarthritic knees. This implant is designed to eliminate excessive loads through the knee and to provide suitable conditions for possible tibiofemoral cartilage regeneration. The implant was designed for the medial side of the knee joint. Finite Element Analysis (FEA) was performed for an extended knee position of the knee joint. Contact pressure distributions on the medial and lateral compartments were investigated as well as stress distributions throughout the implant’s plates. Results with and without the implant were compared, and it was seen that the contact pressures on the surface of the distal femur were reduced by more than 90% after the introduction of the implant.

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A METHOD FOR COMPARISON OF RADIOCARPAL CARTILAGE T2 RELAXATION TIME MAPS AND CONTACT PRESSURE DISTRIBUTIONS IN NORMAL AND INJURED WRISTS

Journal of Musculoskeletal Research ◽

10.1142/s0218957715500128 ◽

2015 ◽

Vol 18 (03) ◽

pp. 1550012

Author(s):

Isaac Chappell ◽

Phil Lee ◽

Terence E. McIff ◽

E. Bruce Toby ◽

Kenneth J. Fischer

Keyword(s):

Contact Pressure ◽

Dimensional Space ◽

Relaxation Times ◽

Three Dimensional ◽

T2 Relaxation ◽

Anatomical Images ◽

Joint Contact ◽

Magnetic Resonance Imaging Mri ◽

Joint Contact Pressure ◽

Contact Pressures

Objective: The goal of this study was to demonstrate a methodology to observe the relationship between joint contact pressure and cartilage T2 relaxation times in three-dimensional space. Methods: One subject diagnosed with unilateral scapholunate dissociation had both injured and uninjured wrists scanned using a Siemens 3T Skyra magnetic resonance imaging (MRI) scanner. Four time echo scans were performed with TE ranging 15–61[Formula: see text]ms with the hand relaxed. T2 maps were constructed using a custom Matlab code, and these maps were registered to anatomical images for the same subject. The anatomical images were used to construct surface contact models and calculate contact pressures for a simple grasp activity in a prior study. Contact pressures and T2 relaxation times were analyzed using regression analysis. Results and Conclusion: This study demonstrates the feasibility of comparing T2 relaxation times and contact pressure data. For this single demonstration subject, it is not surprising that no relationship was found between T2 relaxation times for the articular cartilage and contact pressures in the normal wrist, contact pressures in the wrist with injury, nor contact pressure changes due to injury. However, the method has been demonstrated and may be useful to evaluate the influence of joint injuries or other pathologies on T2 relaxation times in the context of changes in joint contact pressures with larger cohorts of subjects.

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Preliminary biomechanical cadaver study investigating a new load-sharing knee implant

Journal of Experimental Orthopaedics ◽

10.1186/s40634-021-00379-2 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Mehdi Saeidi ◽

Piaras A. Kelly ◽

Christian Netzel ◽

Miriam Scadeng ◽

Pranesh Kumar ◽

...

Keyword(s):

Knee Joint ◽

Contact Pressure ◽

Soft Tissues ◽

Load Sharing ◽

Joint Space ◽

Cnc Machining ◽

Lateral Side ◽

Joint Mechanics ◽

Medial Side ◽

Contact Pressures

Abstract Purpose One of the major contributors to the progression of knee osteoarthritis (OA) is the condition of loading in the knee joint. Innovatively designed load-sharing implants may be effective in terms of reducing joint load. The effects of these implants on contact joint mechanics can be evaluated through cadaver experiments. In this work, a case study is carried out with cadaver knee specimens to carry out a preliminary investigation into a novel load-sharing knee implant, in particular to study the surgical procedures required for attachment, and to determine the contact pressures in the joint with and without the implant. Methods Contact pressure in the tibiofemoral joint was measured using pressure mapping sensors, with and without the implant, and radiographs were conducted to investigate the influence of the implant on joint space. The implant was designed from a 3D model of the specimen reconstructed by segmenting MR images of the knee, and it was manufactured by CNC machining. Results It was observed that attachment of the implant does not affect the geometry of the hard/soft tissues. Radiographs showed that the implant led to an increase in the joint space on the medial side. Contact pressure measurements showed that the implant reduced the load on the medial side by approximately 18% under all tested loading conditions. By increasing the load from 800 to 1600 N, the percentage of load reduction in the lateral side was decreased by 8%. After applying 800, 1200, and 1600 N load it was observed that the peak contact pressures were 3.7, 4.6, and 5.5 MPa, respectively. Conclusions This new knee implant shows some promise as a treatment for OA, through its creation of a conducive loading environment in the knee joint, without sacrificing or damaging any of the hard or soft tissues. This device could be as effective as, for example, the Atlas® system, but without some complications seen with other devices; this would need to be validated through similar results being observed in an appropriate in vivo study.

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Can the Hip Joint be Modeled Accurately Using Simplified Geometry?

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192902 ◽

2008 ◽

Author(s):

Andrew E. Anderson ◽

Steve A. Maas ◽

Benjamin J. Ellis ◽

Jeffrey A. Weiss

Keyword(s):

Contact Pressure ◽

Hip Joint ◽

Spherical Geometry ◽

Model Complexity ◽

Hip Morphology ◽

Joint Contact ◽

Analytical Approaches ◽

Contact Pressures ◽

In Vitro Data

Simplified analytical approaches to estimate hip joint contact pressures using perfectly spherical geometry have been described in the literature (rigid body spring models); however, estimations based on these simulations have not corresponded well with experimental in vitro data. Recent evidence from our laboratory suggests that finite element (FE) models of the hip joint that incorporate detailed geometry for cartilage and bone can predict cartilage pressures in good agreement with experimental data [1]. However, it is unknown whether this degree of model complexity is necessary. The objective of this study was to compare cartilage contact pressure predictions from FE models with varying degrees of simplicity to elucidate which aspects of hip morphology are required to obtain accurate predictions of cartilage contact pressure. Models based on 1) subject-specific (SS) geometry, 2) spheres, and 3) rotational conchoids were analyzed.

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Effect of coronal plane acetabular correction on joint contact pressure in Periacetabular osteotomy: a finite-element analysis

BMC Musculoskeletal Disorders ◽

10.1186/s12891-022-05005-5 ◽

2022 ◽

Vol 23 (1) ◽

Author(s):

Kenji Kitamura ◽

Masanori Fujii ◽

Miho Iwamoto ◽

Satoshi Ikemura ◽

Satoshi Hamai ◽

...

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Contact Pressure ◽

Periacetabular Osteotomy ◽

Anterior Wall ◽

Coronal Plane ◽

Patient Specific ◽

Element Analysis ◽

Joint Contact ◽

Joint Contact Pressure

Abstract Background The ideal acetabular position for optimizing hip joint biomechanics in periacetabular osteotomy (PAO) remains unclear. We aimed to determine the relationship between acetabular correction in the coronal plane and joint contact pressure (CP) and identify morphological factors associated with residual abnormal CP after correction. Methods Using CT images from 44 patients with hip dysplasia, we performed three patterns of virtual PAOs on patient-specific 3D hip models; the acetabulum was rotated laterally to the lateral center-edge angles (LCEA) of 30°, 35°, and 40°. Finite-element analysis was used to calculate the CP of the acetabular cartilage during a single-leg stance. Results Coronal correction to the LCEA of 30° decreased the median maximum CP 0.5-fold compared to preoperatively (p < 0.001). Additional correction to the LCEA of 40° further decreased CP in 15 hips (34%) but conversely increased CP in 29 hips (66%). The increase in CP was associated with greater preoperative extrusion index (p = 0.030) and roundness index (p = 0.038). Overall, virtual PAO failed to normalize CP in 11 hips (25%), and a small anterior wall index (p = 0.049) and a large roundness index (p = 0.003) were associated with residual abnormal CP. Conclusions The degree of acetabular correction in the coronal plane where CP is minimized varied among patients. Coronal plane correction alone failed to normalize CP in 25% of patients in this study. In patients with an anterior acetabular deficiency (anterior wall index < 0.21) and an aspherical femoral head (roundness index > 53.2%), coronal plane correction alone may not normalize CP. Further studies are needed to clarify the effectiveness of multiplanar correction, including in the sagittal and axial planes, in optimizing the hip joint’s contact mechanics.

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Estimating Hip Joint Contact Pressure from Geometric Features

Recent Advances in the 3D Physiological Human ◽

10.1007/978-1-84882-565-9_11 ◽

2009 ◽

pp. 165-177

Author(s):

Ehsan Arbabi ◽

Salman Chegini ◽

Ronan Boulic ◽

Stephen J Ferguson ◽

Daniel Thalmann

Keyword(s):

Contact Pressure ◽

Hip Joint ◽

Geometric Features ◽

Joint Contact ◽

Joint Contact Pressure

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The role of the posterior bundle of the medial collateral ligament in posteromedial rotatory instability of the elbow

The Bone & Joint Journal ◽

10.1302/0301-620x.100b8.bjj-2017-0652.r2 ◽

2018 ◽

Vol 100-B (8) ◽

pp. 1060-1065 ◽

Cited By ~ 8

Author(s):

J-T. Hwang ◽

M. N. Shields ◽

L. J. Berglund ◽

A. W. Hooke ◽

J. S. Fitzsimmons ◽

...

Keyword(s):

Contact Pressure ◽

Medial Collateral Ligament ◽

Lateral Collateral Ligament ◽

Collateral Ligament ◽

Coronoid Fracture ◽

Rotatory Instability ◽

Intact Group ◽

Joint Contact ◽

The Mean ◽

Contact Pressures

Aims The aim of this study was to evaluate two hypotheses. First, that disruption of posterior bundle of the medial collateral ligament (PMCL) has to occur for the elbow to subluxate in cases of posteromedial rotatory instability (PMRI) and second, that ulnohumeral contact pressures increase after disruption of the PMCL. Materials and Methods Six human cadaveric elbows were prepared on a custom-designed apparatus which allowed muscle loading and passive elbow motion under gravitational varus. Joint contact pressures were measured sequentially in the intact elbow (INTACT), followed by an anteromedial subtype two coronoid fracture (COR), a lateral collateral ligament (LCL) tear (COR + LCL), and a PMCL tear (COR + LCL + PMCL). Results There was no subluxation or joint incongruity in the INTACT, COR, and COR + LCL specimens. All specimens in the COR + LCL + PMCL group subluxated under gravity-varus loads. The mean articular contact pressure of the COR + LCL group was significantly higher than those in the INTACT and the COR groups. The mean articular contact pressure of the COR + LCL + PMCL group was significantly higher than that of the INTACT group, but not higher than that of the COR + LCL group. Conclusion In the presence of an anteromedial fracture and disruption of the LCL, the posterior bundle of the MCL has to be disrupted for gross subluxation of the elbow to occur. However, elevated joint contact pressures are seen after an anteromedial fracture and LCL disruption even in the absence of such subluxation. Cite this article: Bone Joint J 2018;100-B:1060–5.

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