Academia.edu no longer supports Internet Explorer.
To browse Academia.edu and the wider internet faster and more securely, please take a few seconds to upgrade your browser.
…
8 pages
1 file
Purpose: Single radius (SR) TKA implant designs are theoretically claimed to overcome “mid-flexion instability” and decrease quadriceps loading encountered in multiple radii (MR) designs. However, limited/no data is available to support SR over MR designs especially in Indian population. Methods: The present study is a randomized controlled trial, comparing SR (n=17) and MR (n=13) knee kinematics based on clinical scores (Knee Society Score; KSS), radiological (Lotke score), fluoroscopic, and electro-goniometric data in patients. Fluoroscopic evaluation was done by contour based (2D/3D) registration technique. Results: Patients demographics, KSS, radiological and electro-goniometric data were comparable between SR and MR TKA groups. Anatomically, axial rotation and condylar lift-off data showed insignificant differences. However, MR TKA knees showed higher (P < 0.05) antero-posterior translation compared to SR TKA knees. Similarly, electro-goniometry data has shown no statistical significant difference between both the groups in terms of unloaded flexion-extension, internal-external rotations, walking, and sitto-stand flexion/rotation. Conclusion: The study showed no statistical significant difference between the two knee implant designs based on clinical, radiological and goniometric data except antero-posterior translation. Mid-flexion instability was not seen with MR TKA which was projected as the major problem with these designs.
Open Journal of Rheumatology and Autoimmune Diseases, 2013
Background: Studies have shown that there are striking variations in knee morphology between Asian and Western population. However, most of the existing total knee arthroplasty (TKA) implants are designed to suit the anatomy of Western population. Our study investigated anthropometry of Indian arthritic knees and compared them to international ethnic groups. Methods: Computed tomography was used to create 3D knee models and obtain anthropometric data of distal femur and proximal tibia of Indian arthritic knees. Femoral measurements included mediolateral length, medial and lateral anteroposterior length, medial and lateral condylar width and aspect ratio. Tibial measurements included mediolateral length, medial, lateral and central anteroposterior length and aspect ratio. A preoperative virtual implantation using Western TKA implants was carried out to visualize anatomical conformity. Results: Statistical analysis results showed that Indian males had significantly larger femoral and tibial mediolateral and anteroposterior width than Indian females; however, femoral and tibial aspect ratio was similar for both. In case of females, significant difference was observed between medial and lateral condylar widths. When compared to knee anthropometry of other ethnic groups, femoral and tibial aspect ratio of Indian knees was found to be similar to the Asian population and different from the Western population. The virtual implantation showed overhang of the femoral component in both lateral and medial regions. Conclusion: Morphological mismatch between Western and Indian knees established the fact that Western implants have drawbacks when implanted in Indian patients. The study also provided a basis for designing gender-specific TKA implants for the Indian population.
Knee Surgery, Sports Traumatology, Arthroscopy, 2014
Purpose Providing correct rotational alignment of femoral component in total knee arthroplasty (TKA) is mandatory to achieve correct kinematics, good ligament balance and patellar tracking. The purpose of this study was to evaluate potential clinical applications of functional flexion axis (FFA) by analysing the differences between pre-and post-implant placement. This evaluation was supported by the analysis of repeatability, assessing the robustness of the proposed method. Methods Anatomical acquisitions and passive kinematics were acquired on 87 patients undergoing TKA using a commercial navigation system. Knee FFA was estimated, before and after implant positioning, from three flexionextension movements between 0 and 120°. The angle between FFA and transepicondylar axis was analysed in frontal and axial planes. Repeatability coefficient and intraclass correlation coefficient (ICC) were used to analyse the reliability and the agreement in identifying the axis. Results The analysed angle presented differences between pre-and post-operative conditions only in the frontal plane (from -8.3 ± 5.5°to -2.8 ± 5.3°) (p \ 0.0001). There was good intraobserver reliability and agreement. Repeatability coefficient ranged between 4.4°( 3.7-4.9°) and 3.4°(2.9-3.8°), the ICC between 0.87 (0.83-0.91) and 0.93 (0.90-0.95) and the standard deviation ranged between 1.3 and 1.0°. Conclusions The present study demonstrated that TKA affected the estimation of FFA only in the frontal plane. This method reported good repeatability, demonstrating its usefulness for clinical purposes particularly to evaluate rotational positioning of the femoral component in the axial plane. Level of evidence Case series, Level IV.
SICOT-J, 2016
Introduction: Patient satisfaction after total knee replacement (TKR) depends on the amount of pain relief and the functional activities achieved. An important criterion of good functional outcome is the amount of flexion achieved and whether the patient can manage high flexion activities. In order to increase the amount of safe flexion, various implant designs have been developed. This study aims to compare the outcome after TKR using two contemporary high flexion knee designs: Sigma CR150 High Flex Knee prosthesis (Depuy, Warsaw, Indiana) and NexGen High Flex Knee prosthesis (Zimmer, Warsaw, Indiana). Material: A retrospective study was conducted with 100 cases of each design and their functional and radiological outcome was assessed after two years of follow-up. Results: The two groups had comparable results in terms of subjective satisfaction, range of motion achieved and radiological outcome. Depuy group fared better than Zimmer in terms of functional outcome (modified Oxford knee score). Conclusion: Depuy group was found to have fared better than Zimmer in terms of functional outcome. However, it is very difficult to rate one design above the other based on our small sample size and short duration of follow-up.
The Journal of arthroplasty, 2004
Knee arthroplasty implants are designed with features that provide varying articular constraint over the range of flexion such that the pattern of knee motion may also vary. Because the motions of total knee implants have a direct influence on patient function and device longevity, it is important to understand how knee implants based on a variety of design philosophies perform in vivo. Fifty-nine knees in patients with 5 designs of implants were studied with fluoroscopic imaging during gait and stair-climbing activities. Many knees showed significantly different kinematics between the gait and stair activities, as well as differences from knees having other implant designs. The measured motions were consistent with the intrinsic constraint provided by the implant components and the variation in constraint over the flexion range.
Journal of Orthopaedic Research, 2000
This study evaluated the influence of the geometric configuration of the tibial joint area on the kinematics of the knee. Twenty-two patients with noninflammatory arthritis and minor preoperative deformity were studied. They each received an AMK total knee replacement with retention of the posterior cruciate ligament. Eleven patients without any knee abnormalities were used as controls. The patients were stratified to either the flat (terminology of the manufacturer: standard) or concave (terminology of the manufacturer: constrained) polyethylene insert (n = 11 in each group). Knee kinematics were assessed 1 year after the operation by having the patient ascend a platform corresponding to an extension of the knee from 50 to 70" of flexion. During this motion, two film-exchangers simultaneously exposed six to 13 pairs of serial stereoradiographs. The concave geometric configuration of the tibial insert resulted paradoxically in increased anterior-posterior translations compared with the flat insert but no significant change of rotations and translations in the other directions. Compared with normal knees, the most obvious abnormality was increased anterior-posterior translations (p < 0.004). At SO" of flexion, the implants with the flat tibial polyethylene insert had displaced 2 times and the concave ones had displaced 2.5 times more posteriorly than the normal knees (p 5 0.001). Less internal tibial rotation was also recorded in the flexed positions for both types of inserts compared with the normal knees (p < 0.02). Four knees in four patients, who reported symptoms of instability and abnormal knee function, showed significantly increased proximal displacement of the center of the tibial plateau in the flexed position. The findings suggest that current prosthetic designs and surgical technique do not restore normal knee kinematics and indicate that design improvements should rely on in vivo kinematic studies. ~ Recently, more conforming total knee replacement designs have become popular due to concerns about high contact stresses resulting in wear and delamination of the polyethylene (6,23,26). The choice of joint design and the degree of constraint also influence the kinematics and thereby the function of the knee joint. Previous studies have shown that total knee replacements are associated with abnormal kinematics (2.5, 24,25). Nilsson et al. studied the kinematics of the Tricon knee (15) and found anterior-posterior translations approximately double those of normal knees. This finding was attributed to insufficient function of the posterior cruciate ligament. Later, the same abnormality was noted in other designs that spared the posterior cruciate ligament (14J6). These previous studies used dynamic methods with limited resolution or were based on static measurements. Many were done with the patient in the supine or prone position. Few studies used a randomized de
International Orthopaedics, 2014
Purpose Posterior stabilised (PS) total knee arthroplasty (TKA) design development that focused on restoring normal knee kinematics was followed by the introduction of reasonguided motion designs. Although all PS fixed-bearing knee designs were thought to have similar kinematics, reports show they have differing incidences and magnitudes of posterior femoral rollback and axial rotation. In this retrospective comparative study between two guided-motion total knee systems, we hypothesised that kinematic pattern has an influence on clinical and functional outcomes. Methods This study represents the continuation of a previously reported clinical and kinematics analysis. We retrospectively reviewed 347 patients treated with two different TKA designs: Scorpio NRG (Stryker Orthopedics) and Journey Bi-Cruciate Stabilised (BCS) knee system (Smith & Nephew). Two hundred and eighty-one patients were assessed clinically. Patients were divided into groups according to implanted TKA. Clinical evaluation with the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire was performed. Fifteen Scorpio NRG and 16 Journey BCS patients underwent video fluoroscopy during stair climbing, chair rising/sitting and step up/down at six months of follow-up. Results At an average 29 months of clinical follow-up, patients with Journey BCS TKAs reported better clinical results. Stiffness was more frequently reported in the Journey group (5.2 % vs 1.2 %), whereas anterior knee pain was observed in the Scorpio NRG group (1.9 %) only. Both prosthetic models reported different posterior translation of the medial and lateral contact points (CP) in all analysed motor tasks during knee flexion (BCS 10-18 mm; NRG Scorpio 2-3 mm). Both designs produced progressive external rotation of the femoral component relative to the tibia during flexion. Conclusions Journey BCS showed statistically significant better KOOS results. The higher posterior femoral rollback observed in the kinematic assessment of this design, associated with a better patellofemoral design, may be the reason for better clinical outcome. The reported cases of stiffness and anterolateral joint pain could be attributed to excessive medial and lateral tibiofemoral posterior translation. The NRG group demonstrated good axial rotation, but this was not coupled with physiological kinematic patterns. Patellofemoral pain can be explained by a less friendly femoral-groove design. TKA clinical-functional outcome and complications were highly influenced by the bearing geometry and kinematic pattern of prosthetic designs.
Pakistan Journal of Medical and Health Sciences, 2022
Background: Osteoarthritis of the knee is the most common cause of functional impairment in the elderly. A complete knee arthroplasty is the most common knee operation for patients with advanced osteoarthritis. A complete knee arthroplasty is a surgical procedure that is used to treat osteoarthritis in its most severe form." Rheumatoid arthritis, advanced degenerative arthritis, and other forms of this type of osteoarthritis fall under this category. This way of treating different types of arthritis is both highly successful and completely risk-free. MP-TKR and PS-TKR designs have been proven to be beneficial only through a little amount of research so far. So, the aim of this study was to compare the mean range of motion by using two different types of implants i.e. high flexed posterior stabilized implant and medial pivot implant. Objectives: To compare the mean range of motion, in patients with advanced arthritis, treated with total knee arthroplasty, by using two different types of implants i.e. high flexed posterior stabilized implant and medial pivot implant. Study design: It is Randomized Comparative Trial.
Clinical Orthopaedics and Related Research, 2008
With substantial interest devoted to improving knee flexion after TKA, it is important to document the relationship between high range of motion and patient-rated outcomes shown. We therefore asked whether single-design high-flexion mobile-bearing posterior-stabilized TKA resulted in: (1) improved knee function; (2) satisfying subjective results; (3) participation recreational and sporting activities; and (4) function correlated to the final range of motion. We prospectively followed 445 consecutive patients having 516 TKAs from September 2000 to January 2005. The same high-flexion posterior-stabilized mobilebearing implant was used in all patients. Mean patient age was 71 ± 8 years and mean body mass index was 28 ± 4 kg/m 2. The minimum clinical followup was 2 years (mean, 3 years; range, 2-4 years). The postoperative range of knee flexion was 128°± 4°and the mean Knee Society function and knee scores were 91 ± 6 and 96 ± 3, respectively. Eighty-two percent of patients were involved in sporting activities and 86% returned to their previous level of activity. These data confirm that high postoperative range of knee flexion improve patient-rated outcomes. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Acta orthopaedica Belgica, 2009
Achieving a large range of motion (ROM) is a much-desired clinical outcome after total knee arthroplasty (TKA), especially in Asian and Middle Eastern cultures. TKA design plays an important role in providing the post-operative ROM. This study investigated the kinematics of a new high-flexion posterior cruciate ligament retaining total knee replacement, featuring an enlarged posterior condylar offset and a more conforming tibiofemoral articulation. Two flexion activities were compared to determine which provides higher flexion kinematics. Sixteen North American patients with 20 total knee implants were studied using fluoroscopy and shape matching techniques. Maximum skeletal flexion during a lunge activity averaged 120 degrees +/- 11 degrees, with 11 degrees +/- 4 degrees tibial internal rotation. Kneeling activities showed 11 degrees greater average maximum skeletal flexion (131 degrees +/- 13 degrees, p < 0.05) and 1 degrees less tibial internal rotation (10 degrees +/- 4 degre...
Frontiers in Mechanical Engineering, 2022
Total Knee Arthroplasty (TKA) proposed as an alternative treatment for damaged knee joints of humans is reviewed. The commercial application of TKA can help patients to improve their daily normal activities. Here the high-flex type total knee arthroplasty (High-Flex TKA) is typically designed for the patient's convenience on which the greater range of motion can be adjusted for extreme activities such as Seiza and Muslim praying. However, the present High-Flex TKAs have not fulfilled the needs of Indonesians for religious activities with a flexion angle of 150°-165°. Therefore, this review aims to examine the flexion range of High-Flex TKAs proposed for the needs of Indonesians. This study is a narrative review, all studies published and reviewed are related to the range of flexion angles on the use of products from many manufacturers and various types that have been used by patients, as well as the development of a CAD-based TKA design. It was proposed in the present study that the flexion angle on High-Flex TKAs may be optimized by thickening the posterior femoral condyle, creating a medial pivot system, and applying a single radius system on the femoral component. Whereas, the tibial insert component could be designed by setting up the posterior tibial slope, and creating a post-cam stabilizer mechanism. Many knowledge gaps related to the population of research objects, lack of research on extreme angles, development of TKA components, are discussed. Further needs of extensive research on TKA in Mongoloid races are anticipated to be introduced for extreme angles and most comprehensive product development for optimization of the flexion angle.
Teresianum, 2017
Revista proyecto, progreso, arquitectura, 2013
Revue Thomiste, 1980
Die Energiewende im Bundestag: ein politisches Transformationsprojekt?, 2021
Anais do Congresso Nacional Universidade, EAD e Software Livre, 2020
Encyclopedia of Personality and Individual Differences, 2020
International Journal of Fisheries and Aquatic Studies, 2018
Documentos De Trabajo De La Facultad De Ciencias Economicas Y Empresariales, 1990
Lecture Notes in Computer Science, 2009
Pakistan Journal of Biological Sciences, 2006
Metabolic Syndrome and Related Disorders, 2009
International Journal of Preventive Medicine, 2021
Economic Computation and Economic Cybernetics Studies and Research, 2019