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Patrick Sadoghi - One of the best experts on this subject based on the ideXlab platform.
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sex related outcome differences after implantation of low Contact Stress mobile bearing total knee arthroplasty
International Orthopaedics, 2012Co-Authors: Norbert Kastner, Gerald Gruber, Birgit Aigner, Jorg Friesenbichler, Michael Pechmann, F C Furst, Patrick Vavken, Andreas Leithner, Patrick SadoghiAbstract:Purpose The aim of the study was to investigate outcome differences between female and male patients after implantation of low-Contact-Stress (LCS) mobile-bearing total knee prostheses at a minimum follow-up of five years with respect to clinical and radiological parameters.
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sex related outcome differences after implantation of low Contact Stress mobile bearing total knee arthroplasty
International Orthopaedics, 2012Co-Authors: Norbert Kastner, Gerald Gruber, Birgit Aigner, Jorg Friesenbichler, Michael Pechmann, Patrick Vavken, Andreas Leithner, Florentine Furst, Patrick SadoghiAbstract:The aim of the study was to investigate outcome differences between female and male patients after implantation of low-Contact-Stress (LCS) mobile-bearing total knee prostheses at a minimum follow-up of five years with respect to clinical and radiological parameters. We retrospectively analysed 128 prostheses in 126 patients (90 women and 34 men) using our hospital database. Data was extracted with respect to range of motion (ROM), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the Knee Society Score (KSS) and radiolucent lines on conventional X-rays. At follow-up, we observed no significant differences between female and male patients after LCS total knee prostheses. Benefit after implantation of LCS total knee prostheses after five years of minimum follow-up was not significantly different between female and male patients in terms of clinical outcome or radiolucent lines. We found no factors in favour of gender-specific total knee prostheses.
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radiolucent lines in low Contact Stress mobile bearing total knee arthroplasty a blinded and matched case control study
BMC Musculoskeletal Disorders, 2011Co-Authors: Norbert Kastner, Gerald Gruber, Jorg Friesenbichler, Andreas Leithner, Patrick Sadoghi, Patrick Weber, Katrin Pohlmann, Volkmar Jansson, Bernd WegenerAbstract:Background: Low-Contact-Stress (LCS) mobile-bearing total knee arthroplasty (TKA) (Johnson & Johnson, New Brunswick, NJ; previously: DePuy, Warsawa, USA) provides excellent functional results and wear rates in long-term follow-up analyses. Radiological analysis shows radiolucent lines (RLL) appearing immediately or two years after primary implantation, indicative of poor seat. Investigations proved RLL to be more frequent in uncemented TKA, resulting in a consensus to cement the tibial plateau, but their association with clinical findings and patients discomfort and knee pain is still unknown. Methods: 553 patients with 566 low-Contact-Stress (LCS) total knee prostheses were screened for continuous moderate knee pain. We compared tibial Stress shielding classified by Ewald in patients suffering from pain with a matched, painfree control group on blinded X-rays. We hypothesized a positive correlation between pain and radiolucency and higher frequency of such radiolucent lines in the most medial and most lateral zones of the tibial plateau. Results: Twenty-eight patients suffered from knee pain in total. Radiolucencies were detected in 27 of these cases and in six out of 28 matched controls without knee pain. We could demonstrate a significant correlation of knee pain and radiolucencies, which appeared significantly more frequently in the outermost zones of the tibial plateau. Conclusion: Our findings suggest that radiolucent lines, representing poor implant seat, about the tibial plateau are associated with knee pain in LCS patients. Radiolucencies are observed more often in noncemented LCS, and cementing the tibial plateau might improve implant seat and reduce both radiolucent lines and associated knee pain.
Yukihide Iwamoto - One of the best experts on this subject based on the ideXlab platform.
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Contact Stress analysis of the anterior tibial post in bi cruciate stabilized and mobile bearing posterior stabilized total knee arthroplasty designs
Journal of The Mechanical Behavior of Biomedical Materials, 2016Co-Authors: Umito Kuwashima, Satoshi Hamai, Hidehiko Higaki, Ken Okazaki, Satoru Ikebe, Hideki Mizuuchi, Yukio Akasaki, Koji Murakami, Yukihide IwamotoAbstract:Abstract In posterior-stabilized (PS) total knee arthroplasty (TKA), unexpected wear and fracture of the tibial post due to anterior post impingement have been reported. The purpose of this study was to determine the Contact Stress on the anterior aspect of the tibial post in four contemporary TKA designs. We evaluated one bi-cruciate stabilized design (Journey II) and three mobile-bearing PS designs (Vanguard RP, PFC Sigma RP, and NexGen LPS Mobile). The Contact conditions at the anterior aspect of the tibial post were determined upon application of a posterior force of 100 N to individual implants. Each measurement was sequentially performed five times, and the data were compared within and across designs using analysis of variance and a post-hoc test. The Contact Stress of the Journey II and Vanguard RP was less than the compressive yield Stress for polyethylene (10 MPa) at all tested flexion angles and degrees of rotation. The PFC Sigma RP did not show anterior tibial post impingement under any experimental conditions. The NexGen LPS Mobile demonstrated bilateral edge loading at the anterior tibial post and exceeded 10 MPa of Contact Stress in some test conditions. Thus, the differences among implants in terms of the dimensions of the femoral anterior cam or intercondylar notch and the anterior aspect of the tibial post in the axial and sagittal planes led to significant differences in Contact conditions. The present study helps the surgeon to be more aware that various Contact conditions of the anterior aspect of the tibial post can occur in individual TKA designs.
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Contact Stress at the anterior aspect of the tibial post in posterior stabilized total knee replacement
Journal of Bone and Joint Surgery American Volume, 2010Co-Authors: Satoshi Hamai, Hiromasa Miura, Shuichi Matsuda, Takeshi Shimoto, Hidehiko Higaki, Yukihide IwamotoAbstract:Background: Retrieval studies have demonstrated polyethylene wear and deformation of the anterior aspect of the tibial post of posterior-stabilized total knee replacements. We are not aware of any study that has analyzed the effects of the design of the femoral notch and the anterior aspect of the tibial post of posterior-stabilized total knee replacements on Contact area, Stress, and location. The purpose of the present study was to determine the levels of Contact Stress generated in three posterior-stabilized total knee replacement designs when the femoral intercondylar notch impinges on the anterior aspect of the tibial post. Methods: The Contact area, mean and peak Contact Stresses, and Contact location at the anterior aspect of the tibial post were determined when a posterior force of 100 N was applied to a NexGen LPS Flex, Genesis II, and Scorpio NRG total knee replacement. Measurements were performed at –15°, –10°, –5°, 0°, and 5° of flexion of the femoral component both in neutral and with 5° of rotation of the tibial component. Each measurement was sequentially performed five times, and the data were compared within and between the designs with use of analysis of variance and a post-hoc Scheffe F test. Results: The NexGen LPS Flex exhibited two Contact areas on the medial and lateral corners of the anterior aspect of the post, whereas both the Genesis II and Scorpio NRG exhibited a single horizontal band. The NexGen LPS Flex showed the largest total Contact area of the three designs at –15°, –10°, and 5° of flexion. The NexGen LPS showed the lowest mean Contact Stress at –15° and 5° but showed the highest peak Contact Stress at –5° and 0°. The Scorpio NRG showed the highest mean Contact Stress under all conditions and showed the highest peak Contact Stress at –15°, –10°, and 5°. With 5° of rotation of the tibial component, peak Contact Stress increased, relative to neutral, 1.2 to twofold (depending on the flexion angle) in the Genesis II design. Conclusions: The mean and peak Contact Stresses were variable for all three designs and the test conditions, approaching and in some cases exceeding the compressive yield Stress for polyethylene. The geometry of the metal femoral notch and polyethylene tibial post in the axial and sagittal planes significantly affected Contact area, mean and peak Stresses, and Contact location at the anterior aspect of the tibial post. Clinical Relevance: This study helps the surgeon to be more aware that high Contact Stresses under some conditions could lead to deformation and damage of the anterior aspect of the post in these three common designs of cruciate-sparing total knee replacements.
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Contact Stress at the post cam mechanism in posterior stabilised total knee arthroplasty
Journal of Bone and Joint Surgery-british Volume, 2005Co-Authors: Koichi Nakayama, Hiromasa Miura, Shuichi Matsuda, Hidehiko Higaki, K Otsuka, Yukihide IwamotoAbstract:We measured the Contact areas and Contact Stresses at the post-cam mechanism of a posterior-stabilised total knee arthroplasty when a posterior force of 500 N was applied to the Kirschner Performance, Scorpio Superflex, NexGen LPS Flex Fixed, and NexGen LPS Flex Mobile knee systems. Measurements were made at 90°, 120°, and 150° of flexion both in neutral rotation and 10° of internal rotation of the tibial component. Peak Contact Stresses at 90°, 120°, and 150° were 24.0, 33.9, and 28.8 MPa, respectively, for the Kirschner; 26.0, 32.4, and 22.1 MPa, respectively, for the Scorpio; and 34.1, 31.5, and 32.5 MPa, respectively, for the NexGen LPS Flex Fixed. With an internally rotated tibia, the Contact Stress increased significantly with all the fixed-bearing arthroplasties but not with the NexGen LPS Flex Mobile arthroplasty. The post-cam design should be modified in order to provide a larger Contact area whilst avoiding any impingement and edge loading.
Shuichi Matsuda - One of the best experts on this subject based on the ideXlab platform.
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Contact Stress at the anterior aspect of the tibial post in posterior stabilized total knee replacement
Journal of Bone and Joint Surgery American Volume, 2010Co-Authors: Satoshi Hamai, Hiromasa Miura, Shuichi Matsuda, Takeshi Shimoto, Hidehiko Higaki, Yukihide IwamotoAbstract:Background: Retrieval studies have demonstrated polyethylene wear and deformation of the anterior aspect of the tibial post of posterior-stabilized total knee replacements. We are not aware of any study that has analyzed the effects of the design of the femoral notch and the anterior aspect of the tibial post of posterior-stabilized total knee replacements on Contact area, Stress, and location. The purpose of the present study was to determine the levels of Contact Stress generated in three posterior-stabilized total knee replacement designs when the femoral intercondylar notch impinges on the anterior aspect of the tibial post. Methods: The Contact area, mean and peak Contact Stresses, and Contact location at the anterior aspect of the tibial post were determined when a posterior force of 100 N was applied to a NexGen LPS Flex, Genesis II, and Scorpio NRG total knee replacement. Measurements were performed at –15°, –10°, –5°, 0°, and 5° of flexion of the femoral component both in neutral and with 5° of rotation of the tibial component. Each measurement was sequentially performed five times, and the data were compared within and between the designs with use of analysis of variance and a post-hoc Scheffe F test. Results: The NexGen LPS Flex exhibited two Contact areas on the medial and lateral corners of the anterior aspect of the post, whereas both the Genesis II and Scorpio NRG exhibited a single horizontal band. The NexGen LPS Flex showed the largest total Contact area of the three designs at –15°, –10°, and 5° of flexion. The NexGen LPS showed the lowest mean Contact Stress at –15° and 5° but showed the highest peak Contact Stress at –5° and 0°. The Scorpio NRG showed the highest mean Contact Stress under all conditions and showed the highest peak Contact Stress at –15°, –10°, and 5°. With 5° of rotation of the tibial component, peak Contact Stress increased, relative to neutral, 1.2 to twofold (depending on the flexion angle) in the Genesis II design. Conclusions: The mean and peak Contact Stresses were variable for all three designs and the test conditions, approaching and in some cases exceeding the compressive yield Stress for polyethylene. The geometry of the metal femoral notch and polyethylene tibial post in the axial and sagittal planes significantly affected Contact area, mean and peak Stresses, and Contact location at the anterior aspect of the tibial post. Clinical Relevance: This study helps the surgeon to be more aware that high Contact Stresses under some conditions could lead to deformation and damage of the anterior aspect of the post in these three common designs of cruciate-sparing total knee replacements.
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Contact Stress at the post cam mechanism in posterior stabilised total knee arthroplasty
Journal of Bone and Joint Surgery-british Volume, 2005Co-Authors: Koichi Nakayama, Hiromasa Miura, Shuichi Matsuda, Hidehiko Higaki, K Otsuka, Yukihide IwamotoAbstract:We measured the Contact areas and Contact Stresses at the post-cam mechanism of a posterior-stabilised total knee arthroplasty when a posterior force of 500 N was applied to the Kirschner Performance, Scorpio Superflex, NexGen LPS Flex Fixed, and NexGen LPS Flex Mobile knee systems. Measurements were made at 90°, 120°, and 150° of flexion both in neutral rotation and 10° of internal rotation of the tibial component. Peak Contact Stresses at 90°, 120°, and 150° were 24.0, 33.9, and 28.8 MPa, respectively, for the Kirschner; 26.0, 32.4, and 22.1 MPa, respectively, for the Scorpio; and 34.1, 31.5, and 32.5 MPa, respectively, for the NexGen LPS Flex Fixed. With an internally rotated tibia, the Contact Stress increased significantly with all the fixed-bearing arthroplasties but not with the NexGen LPS Flex Mobile arthroplasty. The post-cam design should be modified in order to provide a larger Contact area whilst avoiding any impingement and edge loading.
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Contact Stress analysis in meniscal bearing total knee arthroplasty
Journal of Arthroplasty, 1998Co-Authors: Shuichi Matsuda, Stephen E White, Victor G Williams, Daniel S Mccarthy, Leo A WhitesideAbstract:Abstract The effect of a mobile meniscal bearing on tibiofemoral Contact Stress was tested with a standard fixed tibial component and with movable tibial components (anteroposterior sliding, rotationally sliding, and anteroposterior and rotationally sliding). A digital electronic sensor was used to detect tibiofemoral Contact location in five cadaver knees, then the location was reproduced while peak and mean Stresses were measured under compressive load at 0°, 30°, 60°, and 90° of flexion. Stresses were measured when the tibial component was normally aligned and at 15° internal and 15° external rotation. To evaluate the effect of excessive overhang of the polyethylene articular surface, undersurface Stress of the rotationally sliding component was also measured with a 30° and a 45° malrotated tibial tray. Uppersurface Stresses of the fixed-bearing components were significantly higher at full extension than those recorded in components with rotational mobility. Undersurface Stresses were always lower than uppersurface Stresses, but correlated with uppersurface Stresses. Undersurface Stresses of the rotationally sliding component gradually increased as the malrotation angle of the tray increased. A mobile meniscal bearing surface appears to offer an advantage over a standard fixed component when rotational malalignment of the tibial component occurs. However, with severe rotational malalignment, edge Contact markedly increases undersurface Stresses, which could cause deformity and subluxation.
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patellofemoral joint after total knee arthroplasty effect on Contact area and Contact Stress
Journal of Arthroplasty, 1997Co-Authors: Shuichi Matsuda, Stephen E White, Takashi Ishinishi, Leo A WhitesideAbstract:Abstract Compressive Contact Stress between the patella and the anterior femur and between the quadriceps tendon and anterior femur was measured before and after total knee arthroplasty in 5 cadaver knee specimens using a digital electronic sensor. Contact Stresses were measured in the normal knee and after total knee arthroplasty with an unresurfaced patella, a dome-shaped patella, and a conforming patella. Patellofemoral Contact Stresses did not change significantly after total knee arthroplasty when the patella was not resurfaced, but they increased significantly after the patella was resurfaced with both the dome-shaped and the conforming components. The conforming patella had the highest Contact Stresses because it tilted at flexion angles greater than 90° and applied load to a small area on the superior portion of the patellar component. The conforming patella markedly decreased tendofemoral Contact force because the thicker superior pole of the patella tented the quadriceps tendon at flexion angles greater than 120°. This further increased patellofemoral Contact force in deep knee flexion.
Fangyuan Ho - One of the best experts on this subject based on the ideXlab platform.
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long term results of low Contact Stress mobile bearing total knee replacements
Clinical Orthopaedics and Related Research, 2003Co-Authors: Chunhsiung Huang, Fangyuan HoAbstract:: Five hundred ninety-eight consecutive primary low Contact Stress total knee replacements were done in 502 patients between 1985 and 1990. Clinical review was available for 495 knees (406 patients), 228 knees with meniscal-bearing prostheses and 267 knees with rotating-platform prostheses. The average followup was 12 years (range, 10-15 years). The average postoperative knee and functional scores were 87 points and 75 points, respectively. The average postoperative range of motion was 110 degrees. Fifty-six knees (11%) required revision for excessive wear of the tibial insert (41), dislocation (10), patellar polyethylene breakage (one), component loosening (one patellar, one tibial), and infection (two). During revision, osteolysis (20 knees), patellar polyethylene failure (33), and femoral component fracture (one) were seen. The overall survivorship was 88.1% at 15 years using Kaplan-Meier analysis. The survival rate was 83% for the meniscal-bearing prostheses and 92.1% for the rotating-platform prostheses. The Low Contact Stress mobile-bearing knee prosthesis has no superiority over that of fixed-bearing knees, especially for the meniscal-bearing design in prevention of polyethylene failure or revision. Based on the results of this study, the use of the LCS meniscal-bearing prosthesis does not appear to be justified.
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late dislocation of rotating platform in new jersey low Contact Stress knee prosthesis
Clinical Orthopaedics and Related Research, 2002Co-Authors: Chunhsiung Huang, Jiannjong Liau, Fangyuan Ho, Chengkung ChengAbstract:Five patients with late rotational dislocation of the rotating platform bearing in the New Jersey Low-Contact Stress total knee arthroplasty are reported. The prostheses had functioned well for 8 to 12 years before failure. Preoperative radiographs showed asymmetric femorotibial joint spaces. Entrapment of the dislocated bearing in three patients and spontaneous reduction of the dislocated bearing in another two patients were seen at revision. Femorotibial ligamentous instability was found after reduction. The retrieved polyethylene bearings showed advanced wear and cold flow deformities and the thickness was reduced. The revision arthroplasty was accomplished by replacement with a thicker bearing element. Progressive femorotibial ligament laxity and reduction of the thickness of polyethylene with wearing break down the originally well-balanced soft tissue tension of the knee. The rotational degree of the rotating platform bearing is unrestricted, which may result in late dislocation. Polyethylene wear is unavoidable in knee prostheses using metal Contact with polyethylene even with a mobile-bearing design. Efforts to reduce polyethylene wear are mandatory.
Chunhsiung Huang - One of the best experts on this subject based on the ideXlab platform.
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long term results of low Contact Stress mobile bearing total knee replacements
Clinical Orthopaedics and Related Research, 2003Co-Authors: Chunhsiung Huang, Fangyuan HoAbstract:: Five hundred ninety-eight consecutive primary low Contact Stress total knee replacements were done in 502 patients between 1985 and 1990. Clinical review was available for 495 knees (406 patients), 228 knees with meniscal-bearing prostheses and 267 knees with rotating-platform prostheses. The average followup was 12 years (range, 10-15 years). The average postoperative knee and functional scores were 87 points and 75 points, respectively. The average postoperative range of motion was 110 degrees. Fifty-six knees (11%) required revision for excessive wear of the tibial insert (41), dislocation (10), patellar polyethylene breakage (one), component loosening (one patellar, one tibial), and infection (two). During revision, osteolysis (20 knees), patellar polyethylene failure (33), and femoral component fracture (one) were seen. The overall survivorship was 88.1% at 15 years using Kaplan-Meier analysis. The survival rate was 83% for the meniscal-bearing prostheses and 92.1% for the rotating-platform prostheses. The Low Contact Stress mobile-bearing knee prosthesis has no superiority over that of fixed-bearing knees, especially for the meniscal-bearing design in prevention of polyethylene failure or revision. Based on the results of this study, the use of the LCS meniscal-bearing prosthesis does not appear to be justified.
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late dislocation of rotating platform in new jersey low Contact Stress knee prosthesis
Clinical Orthopaedics and Related Research, 2002Co-Authors: Chunhsiung Huang, Jiannjong Liau, Fangyuan Ho, Chengkung ChengAbstract:Five patients with late rotational dislocation of the rotating platform bearing in the New Jersey Low-Contact Stress total knee arthroplasty are reported. The prostheses had functioned well for 8 to 12 years before failure. Preoperative radiographs showed asymmetric femorotibial joint spaces. Entrapment of the dislocated bearing in three patients and spontaneous reduction of the dislocated bearing in another two patients were seen at revision. Femorotibial ligamentous instability was found after reduction. The retrieved polyethylene bearings showed advanced wear and cold flow deformities and the thickness was reduced. The revision arthroplasty was accomplished by replacement with a thicker bearing element. Progressive femorotibial ligament laxity and reduction of the thickness of polyethylene with wearing break down the originally well-balanced soft tissue tension of the knee. The rotational degree of the rotating platform bearing is unrestricted, which may result in late dislocation. Polyethylene wear is unavoidable in knee prostheses using metal Contact with polyethylene even with a mobile-bearing design. Efforts to reduce polyethylene wear are mandatory.
