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

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.

scholarly journals Digital Radiographic Assessment of Knee Joint Space with its Clinical Significances

2020 ◽  
Vol 5 (1) ◽  
pp. 976-980
Author(s):  
Dil Islam `Mansur ◽  
Subindra Karki ◽  
Dilip Kumar Mehta ◽  
Pragya Shrestha ◽  
Sunima Maskey
Keyword(s):  
Knee Joint ◽  
Joint Space Width ◽  
Joint Space ◽  
Left Knee ◽  
Lateral Side ◽  
Cross Sectional ◽  
Mean Values ◽  
Medial Side ◽  
Digital Radiograph ◽  
The Right

Introduction: The knee joint space is seen on anteroposterior radiograph as a radiolucent area between lower end of femur and upper end of tibia which is an indirect way of evaluating the knee cartilage thickness.  Objective: This study was aimed to determine the knee joint space in the medial and lateral compartments of the knee joint using digital radiograph.  Methodology : This was cross-sectional study. It consisted of digital radiographs of knee joint of 320 individuals. The medial and lateral joint space width of each knee joint was measured using the scale in the computerized software.  Results: The mean values for medial and lateral joint space widths were found to be 6.11±1.57 mm and 7.92±1.66 mm of the right knee joint respectively and 5.99±1.47 mm and 8.18±1.69 mm of the left knee joint respectively. In males, mean values for joint space widths were 6.37±1.58 mm on medial side and 8.21±1.67 mm on lateral side of the right knee; and 6.24±1.56 mm on medial side and 8.33±1.64 mm on lateral side of the left knee. In Females, these values were 5.89±1.53 mm on medial side and 7.66±1.62 mm on lateral side of the right knee; and 5.79±1.37 mm on medial side and 8.06±1.72 mm on lateral side of the left knee.  Conclusions: It was concluded that the lateral joint space was greater than the medial joint space in both knees. The joint space widths were found to be reasonably constant with increasing age among studied population.

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

2011 ◽  
Vol 39 (12) ◽  
pp. 2662-2669 ◽  
Author(s):  
L. Daniel Latt ◽  
Richard R. Glisson ◽  
Harvey E. Montijo ◽  
Federico G. Usuelli ◽  
Mark E. Easley
Keyword(s):  
Contact Pressure ◽  
Osteochondral Allograft ◽  
Lateral Side ◽  
Graft Placement ◽  
Medial Side ◽  
Peak Contact Pressure ◽  
Joint Contact ◽  
Joint Contact Pressure ◽  
Osteochondral Grafting ◽  
Contact Pressures

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.

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

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.

scholarly journals Congenital club foot

2010 ◽  
Vol 57 (1) ◽  
pp. 73-76 ◽  
Author(s):  
Z.S. Vukasinovic ◽  
N.S. Slavkovic ◽  
Z.M. Zivkovic ◽  
V.D. Bascarevic
Keyword(s):  
Surgical Treatment ◽  
Club Foot ◽  
Soft Tissues ◽  
Plantar Flexion ◽  
Lateral Side ◽  
Foot Deformity ◽  
Congenital Clubfoot ◽  
Medial Side ◽  
Success Of Treatment ◽  
Bone Deformities

Congenital club foot is the most frequent foot deformity. It occurs in 1% of newborns, two times more frequently in boys, with family inheritance. Patoanatomicaly, entity consists of bone deformities, articular malpositions and soft tissues retraction. All these produce adduction of the forefoot and varus and equinovarus of the hindfoot. Lateral side of the foot is convex and medial side is concave. Forefoot is in adduction and plantar flexion in relation to the hindfoot. The heel is rotated medially which induces varus and eqinus of the foot. The aim of the treatment is to establish anatomically normal foot, painless, with moderate movements, which is suitable for normal shoes. At the beginning treatment is nonsurgical. If nonsurgical treatment fails further step should be surgical treatment. The success of treatment of congenital clubfoot depends on the time of diagnosis and treatment beginning.

scholarly journals Pressure Change Of Fixed Rotational Deformities In The Femur In Human Cadaver Knees-A Biomechanical Study

2021 ◽  
Author(s):  
Yuwen Peizhi ◽  
Hongzhi Lv ◽  
Yanbin Zhu ◽  
Wenli Chang ◽  
Ning Wei ◽  
...  
Keyword(s):  
Knee Joint ◽  
Internal Rotation ◽  
Contact Pressure ◽  
Tibial Plateau ◽  
Lower Limbs ◽  
Lateral Side ◽  
Neutral Position ◽  
Relative Pressure ◽  
Rotational Deformity ◽  
Significant Difference

Abstract Background: Closed intramedullary interlocking nailing is a standard treatment for femoral shaft fractures, but incidences of rotational malalignment after operation is really high. Poor reduction and postoperative malunion lead to many clinical symptoms and long term degenerative arthritis. It has been proved that uneven stress is the mechanical cause of knee joint degeneration, but few studies pay attention to the effect of femur rotational deformity on knee joint contact pressure.This study aim to quantitatively evaluate the relation between residual rotational deformity in femur and contact pressure of knee joint. Methods: Fourteen cadaveric Lower limbs were selected and autopsied, rotatory fixation model with different angles were then made. Connect each model on the biomechanical machine and apply a vertical load to 400N. The contact pressure was quantitatively measured using ultra-low-pressure sensitive film technology. FPD-305E density meter and FPD-306E pressure converter were used to read relative pressure values. Contact pressure on medial and lateral tibial plateau in different femoral rotational deformities were compared. Analysis were done using SPSS software.Results: The medial group show a significant difference on tibial plateau (F=92.114, P<0.01), further test showed statistically significant differences of pairwise comparisons between 0°, 5°, 10°, 15° internal rotation deformity (P<0.05). There is no significant difference in lateral group (ꭓ2=9.967, P<0.01). The medial contact pressure is 0.940±0.177 MPa and the lateral is 1.008±0.219 MPa at neutral position, no statistically significant was found, so is 5° of internal rotational deformity. But the medial contact pressure are all higher than the lateral side at 5°, 10°, 15° of external rotation, and 10°, 15° of internal rotation. Conclusion: Obvious contact pressure changes on tibial plateau were observed in rotatory deformity femur, which is closely related to the occurrence of knee osteoarthritis. Doctors should detect rotational deformity as much as possible during operation and perform anatomical reduction, for patients with residual rotational deformities, indication of osteotomy should not be too broad.

Maximum Interlabial Pressures in Normal Speakers

1997 ◽  
Vol 40 (2) ◽  
pp. 400-404 ◽  
Author(s):  
Virginia A. Hinton ◽  
Winston M. C. Arokiasamy
Keyword(s):  
Speech Production ◽  
Contact Pressure ◽  
Direct Evidence ◽  
Unit Area ◽  
Jaw Movement ◽  
Contractile Forces ◽  
Contact Pressures ◽  
Muscle Contractile

It has been hypothesized that typical speech movements do not involve large muscular forces and that normal speakers use less than 20% of the maximum orofacial muscle contractile forces that are available (e.g., Amerman, 1993; Barlow & Abbs, 1984; Barlow & Netsell, 1986; DePaul & Brooks, 1993). However, no direct evidence for this hypothesis has been provided. This study investigated the percentage of maximum interlabial contact pressures (force per unit area) typically used during speech production. The primary conclusion of this study is that normal speakers typically use less than 20% of the available interlabial contact pressure, whether or not the jaw contributes to bilabial closure. Production of the phone [p] at conversational rate and intensity generated an average of 10.56% of maximum available interlabial pressure (MILP) when jaw movement was not restricted and 14.62% when jaw movement was eliminated.

scholarly journals AB0867 INCREASED ADIPONECTIN LEVELS ARE ASSOCIATED WITH HIGHER RADIOGRAPHIC SCORES IN THE KNEE JOINT, BUT NOT IN THE HAND JOINT: THE DONG-GU STUDY

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1740.1-1740
Author(s):  
J. H. Kang ◽  
S. E. Choi ◽  
H. Xu ◽  
D. J. Park ◽  
S. S. Lee
Keyword(s):  
Body Mass Index ◽  
Knee Joint ◽  
Body Mass ◽  
Linear Regression Analysis ◽  
Joint Space ◽  
Serum Adiponectin ◽  
Hand Osteoarthritis ◽  
X Rays ◽  
Subchondral Cyst ◽  
The Relationship

Background:Several studies have evaluated the association between serum adiponectin levels and knee and hand osteoarthritis (OA), with mixed results.Objectives:The aim of this study was to investigate the relationship between OA and serum adiponectin levels according to the radiographic features of knee and hand OA.Methods:A total of 2,402 subjects were recruited from the Dong-gu Study. Baseline characteristics were collected via a questionnaire, and X-rays of knee and hand joints were scored by a semi-quantitative grading system. The relationship between serum adiponectin levels and radiographic severity was evaluated by linear regression analysis.Results:Subjects with higher tertiles of serum adiponectin were older and had a lower body mass index than those with lower tertiles. In the knee joint scores, serum adiponectin levels were positively associated with the total score (P<0.001), osteophyte score (P=0.003), and joint space narrowing (JSN) score (P<0.001) among the three tertiles after adjustment for age, sex, body mass index, smoking, alcohol consumption, education, and physical activity. In the hand joint scores, no association was found between serum adiponectin levels and the total score, osteophyte score, JSN score, subchondral cyst score, sclerosis score, erosion score, and malalignment score among the three tertiles after adjustment.Conclusion:In this study, we found that increased adiponectin levels were associated with higher radiographic scores in the knee joint, but not in the hand joint, suggesting different pathophysiologic mechanisms in the development of OA.Disclosure of Interests:None declared

Experimental and Theoretical Study of the Contact Mechanics of Five Total Knee Joint Replacements

1995 ◽  
Vol 209 (4) ◽  
pp. 225-231 ◽  
Author(s):  
T Stewart ◽  
Z M Jin ◽  
D Shaw ◽  
D D Auger ◽  
M Stone ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Knee Joint ◽  
Contact Pressure ◽  
Contact Stress ◽  
Linear Elasticity ◽  
Contact Area ◽  
Elasticity Analysis ◽  
Joint Replacements ◽  
Total Knee ◽  
Maximum Contact

The tibio-femoral contact area in five current popular total knee joint replacements has been measured using pressure-sensitive film under a normal load of 2.5 kN and at several angles of flexion The corresponding maximum contact pressure has been estimated from the measured contact areas and found to exceed the point at which plastic deformation is expected in the ultra-high molecular weight polyethylene (UHMWPE) component particularly at flexion angles near 90°. The measured contact area and the estimated maximum contact stress have been found to be similar in magnitude for all of the five knee joint replacements tested. A significant difference, however, has been found in maximum contact pressure predicted from linear elasticity analysis for the different knee joints. This indicates that varying amounts of plastic deformation occurred in the polyethylene component in the different knee designs. It is important to know the extent of damage as knees with large amounts of plastic deformation are more likely to suffer low cycle fatigue failure. It is therefore concluded that the measurement of contact areas alone can be misleading in the design of and deformation in total knee joint replacements. It is important to modify geometries to reduce the maximum contact stress as predicted from the linear elasticity analysis, to below the linear elastic limit of the plastic component.

Analysis and Comparison of Seal Ability of Premium Tubing Connections under Axial Alternating Load

2013 ◽  
Vol 423-426 ◽  
pp. 2035-2039
Author(s):  
Long Cang Huang ◽  
Yin Ping Cao ◽  
Yang Yu ◽  
Yi Hua Dou
Keyword(s):  
Contact Pressure ◽  
Oil And Gas ◽  
Element Analysis ◽  
Gas Well ◽  
Cycle Number ◽  
Compression Load ◽  
Well Production ◽  
Maximum Contact ◽  
Contact Pressures ◽  
Better Than

In the process of oil and gas well production, tubing connection stand the axial alternating load during open well, shut well and fluid flow. In order to know premium connection seal ability under the loading, two types of P110 88.9mmx6.45mm premium tubing connections which called A connection and B connection are performed with finite element analysis, in which contact pressures and their the regularities distribution on sealing surface are analyzed. The results show that with the increasing of cycle number, the maximum contact pressures on sealing surface of both A connection and B connection are decreased. The decreasing of the maximum contact pressures on B connection is greater than those on A connection. With the increasing of cycle number of axial alternating compression load, the maximum contact pressure on sealing surface of A connection is decreased, and the maximum contact pressure on sealing surface of B connection remains constant. Compared the result, it shows that the seal ability of A connection is better than B connection under axial alternating tension load, while the seal ability of B connection is better than type A connection under axial alternating compression load.

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