Accurate measurement of three-dimensional knee replacement kinematics using single-plane fluoroscopy
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Abstract:
A simple extension of a previously reported object recognition technique has been used to implement a six-degree-of-freedom position/orientation estimator for the measurement of knee replacement motion from two-dimensional (2-D) fluoroscopic images. Computer modeling studies and controlled mechanical tests were performed to assess the accuracy of the technique. The results indicate that knee rotations can be measured with an accuracy of approximately one degree and that sagittal plane translations can be measured with an accuracy of approximately 0.5 mm. The measurement technique is uniquely well suited for performing dynamic kinematic measurements on individuals with knee replacements, and for performing comparative studies among subjects with different designs of knee replacements.Keywords:
Total Knee Replacement
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The aim was to investigate the effects of three anatomical frames using palpable anatomical landmarks of the knee on the net knee joint moments. The femoral epicondyles, femoral condyles, and tibial ridges were used to define the different anatomical frames and the segment end points of the distal femur and proximal tibia, which represent the origin of the tibial coordinate system. Gait data were then collected using the calibrated anatomical system technique (CAST), and the external net knee joint moments in the sagittal, coronal, and transverse planes were calculated based upon the three anatomical frames. Peak knee moments were found to be significantly different in the sagittal plane by approximately 25% (p
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Objectives. Each year approximately 100,000 Medicare patients undergo knee replacement surgery. Patients, referring physicians, and surgeons must consider a variety of factors when deciding if knee replacement is indicated. One factor in this decision process is the likelihood of revision knee replacement after the initial surgery. This study determined the chance that a revision knee replacement will occur and which factors were associated with revision. Methods. Data on all primary and revision knee replacements that were performed on Medicare patients during the years 1985 through 1990 were obtained. The probability that a revision knee replacement occurred was modeled from data for all patients for whom 2 full years of follow-up data were available. Two strategies for linking revisions to a particular primary knee replacement for each patient were developed. Predictive models were developed for each linking strategy. ICD-9-CM codes were used to determine hospitalizations for primary knee replacement and revision knee replacement. Results. More than 200,000 hospitalizations for primary knee replacements were performed, with fewer than 3% of them requiring revision within 2 years. The following factors increase the chance of revision within 2 years of primary knee replacement: (1) male gender, (2) younger age, (3) longer length of hospital stay for the primary knee replacement, (4) more diagnoses at the primary knee replacement hospitalization, (5) unspecified arthritis type, (6) surgical complications during the primary knee replacement hospitalization, and (7) primary knee replacement performed at an urban hospital. Conclusions. Revision knee replacement is uncommon. Demographic, clinical, and process factors were related to the probability of revision knee replacement.
Total Knee Replacement
Joint replacement
Knee arthritis
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Total Knee Replacement
Joint replacement
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Background: Patients with knee osteoarthritis may undergo total knee replacement too early or may delay or underuse this procedure. We quantified these categories of total knee replacement utilization in 2 cohorts of participants with knee osteoarthritis and investigated factors associated with each category. Methods: Data were pooled from 2 multicenter cohort studies that collected demographic, patient-reported, radiographic, clinical examination, and total knee replacement utilization information longitudinally on 8,002 participants who had or were at risk for knee osteoarthritis and were followed for up to 8 years. Validated total knee replacement appropriateness criteria were longitudinally applied to classify participants as either potentially appropriate or likely inappropriate for total knee replacement. Participants were further classified on the basis of total knee replacement utilization into 3 categories: timely (indicating that the patient had total knee replacement within 2 years after the procedure had become potentially appropriate), potentially appropriate but knee not replaced (indicating that the knee had remained unreplaced for >2 years after the procedure had become potentially appropriate), and premature (indicating that the procedure was likely inappropriate but had been performed). Utilization rates were calculated, and factors associated with each category were identified. Results: Among 8,002 participants, 3,417 knees fulfilled our inclusion and exclusion criteria and were classified into 1 of 3 utilization categories as follows: 290 knees (8% of the total and 9% of the knees for which replacement was potentially appropriate) were classified as “timely”, 2,833 knees (83% of the total and 91% of those for which replacement was potentially appropriate) were classified as “potentially appropriate but not replaced”, and 294 knees (comprising 9% of the total and 26% of the 1,114 total knee replacements performed) were considered to be “likely inappropriate” yet underwent total knee replacement and were classified as “premature”. Of the knees that were potentially appropriate but were not replaced, 1,204 (42.5%) had severe symptoms. Compared with the patients who underwent timely total knee replacement, the likelihood of being classified as potentially appropriate but not undergoing total knee replacement was greater for black participants and the likelihood of having premature total knee replacement was lower among participants with a body mass index of >25 kg/m 2 and those with depression. Conclusions: In 2 multicenter cohorts of patients with knee osteoarthritis, we observed substantial numbers of patients who had premature total knee replacement as well as of patients for whom total knee replacement was potentially appropriate but had not been performed >2 years after it had become potentially appropriate. Further understanding of these observations is needed, especially among the latter group. Clinical Relevance: Undergoing total knee replacement too early may result in little or no benefit while exposing the patient to the risks of a major operation, whereas waiting too long may cause limitations in physical activity that in turn increase the risk of additional disability and chronic disease; however, little is known about timing of this surgery. We quantified the extent of premature, timely, and delayed use, and found a high prevalence of both premature and delayed use.
Total Knee Replacement
Joint replacement
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To determine the agreement among orthopedic surgeons' indications for knee replacement, their perceptions of the usefulness of various treatments for osteoarthritis of the knee and their expected outcomes of knee replacement, and to determine the relation between these opinions and the number of knee replacement procedures performed by individual surgeons.Survey.Ontario.All 392 orthopedic surgeons in the province. Of the 325 practising traceable surgeons 234 (72.0%) responded.Indications for knee replacement, perceived usefulness of treatments for osteoarthritis, perceived outcomes of knee replacement and number of knee replacement procedures performed by individual surgeons.The respondents disagreed on how 20 of 34 patient characteristics affected their decision to perform knee replacement surgery. They also disagreed on the usefulness of seven of eight treatments for arthritis of the knee. The respondents demonstrated variation in their expected outcomes of knee replacement. The surgeons who performed more procedures judged, on average, the outcomes to be better and to have fewer complications than the surgeons who performed fewer procedures.Orthopedic surgeons demonstrated disagreement about some of the indications for knee replacement, the usefulness of treatments for arthritis of the knee and the perceived outcomes of knee replacement. The areas of greatest disagreement should be the focus of future research and the development of practice guidelines.
Total Knee Replacement
Joint replacement
Knee arthritis
Knee surgery
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Section I Introduction.- 1 Indications for Knee Replacement-and the Alternatives.- 2 The Spectrum of Total Knee Replacement.- Section II The Portsmouth Knee.- 3 Factors Which Influence Operations for Replacement of the Knee.- 4 The Operation: Introduction, Technique and Aftercare.- 5 Results.- Section III The Total Condylar and Richards Maximum Contact (RMC) Knees.- 6 The Operation: Introduction, Technique and Aftercare.- 7 Results.- Section IV Partial Knee Replacement.- 8 Unicompartmental Replacement and Patello-femoral Replacement.- Section V Epilogue.- 9 The Future.
Total Knee Replacement
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Total Knee Replacement
Knee flexion
Computational model
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Total Knee Replacement
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Objective:To establish the sectional morphological data of knee joint at different functional positions and observe the regularity of changes on the section of knee joint's structures so as to provide the anatomic data for the dynamic MRI imaging diagnosis of knee joint illness.Methods:The sagittal images of knee joint at different functional positions were obtained with low temperature mill cuts technology and a comparison was made with correspondent dynamic MRI images.Results:The morphologic features,positions and the regularity of changes in the structural components,cruciate ligament,menisci and the soft tissue around them were observed at the sagittal section.Conclusions:The structure,morphology,position and the regularity of changes of knee joint at sagittal section were valuable to orthopedic and imaging diagnosis and treatments of knee joint.
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