- Access throughyour institution
Operative Techniques in Orthopaedics
Volume 10, Issue 1,
, Pages 25-39
The reliability of techniques to position a total knee replacement (TKR) is still limited by the relative inaccuracy of the instrumentation. The main obstacle encountered by mechanical instrumentation systems is the inconsistency of the reference points. These reference points are the centers of joint articulation that will allow the establishment of the mechanical axis for the lower limb. These references guide the placement of the bone-cutting guides. At present, it is impossible to accurately locate these articular centers preoperatively. This handicaps the accuracy of the mechanical instruments and limits their accuracy. The goal of the total knee instrumentation procedure is to achieve cuts that are perpendicular to the mechanical axes of the femur and the tibia. The longevity of total knee arthroplasty is closely related to its intraoperative positioning. The computer-assisted procedure offers an effective and novel positioning method that improves the accuracy of the surgical technique of the TKR. We have chosen to present the steps of the computer-assisted TKR technique next to the corresponding steps of a currently available, mechanically based technique that is representative of many that are presently in use.
- FreemanMAR et al.
ICLH-Arthroplasty of the knee: 1968–1977
J Bone Joint Surg
- InsallJN et al.
Total knee arthroplasty
- InsallJN et al.
A comparison of four models of total knee-replacement prostheses
J Bone Joint Surg Am
- InsallJ et al.
The total Condylar prosthesis. A report of the hundred cases
J Bone Joint Surg Am
- GoodfellowJW et al.
Clinical results of the Oxford knee
- RanawatCS et al.
Survivorship analysis and results of total condylar knee arthroplasty
- FengEL et al.
Progressive subluxation and polyethylene wear in total knee replacements with flat articular surfaces
- EckerML et al.
Long-term results after Total Condylar knee arthroplasty. Significance of radiolucent lines
- RitterMA et al.
Radiolucency at the bone-cement interface in total knee replacementSee AlsoMalay - Amboseli National Parks - Manyeleti Game Reserve (2022)Configuring Proxy Settings via GPO on Windows – TheITBros10 Best Embroidery Machines of 2022 (Home & Small Business)
J Bone Joint Surg Am
Total Condylar knee replacement in patients who have rheumatoid arthritis. A ten-year follow-up study
J Bone Joint Surg Am
There are more references available in the full text version of this article.
- Prevalence and predictors of post-operative coronal alignment outliers and their association with the functional outcomes in navigated total knee arthroplasty
2014, Journal of Arthroplasty(Video) Computer Assisted Total Knee Replacement Surgery | Middlesex Hospital
In accordance with our hypothesis, the prevalence of coronal limb alignment outliers was considerably high in our navigated TKA series, and the degree of preoperative coronal deformity was the strongest predictive factor of being an outlier. Improved coronal alignment is one of the claimed inherent advantages of computer-assisted navigation in TKA [28–30], and numerous studies have provided evidence in its favor, claiming that the use of navigation improved coronal alignment in their patient samples [6,13,31,32]. This advantage of improved alignment was evidently echoed by several recent meta-analyses [7–11].
We aimed to determine the prevalence and predictors for being an outlier after navigated TKA and asked whether navigated TKAs with perfect coronal alignment have better functional outcomes than those without it. Alignment was measured in 124 patients (191 knees) with navigated TKAs who were available for 1year functional outcome assessment. The outcomes were compared among the 3 subgroups divided by the deviation of mechanical axis from neutral (0°): the perfect, 0° or within 1°; the acceptable, 1°–3°; and the outlier, beyond 3°. The prevalence of outliers was 20.4%, and the severity of preoperative varus deformity was the strongest predictor. Accuracy of coronal alignment in radiographs did not correlate consistently with functional outcomes.
- Imageless computer navigation in total knee arthroplasty provides superior short term functional outcomes: A meta-analysis
2014, Journal of Arthroplasty
Three were eliminated for using image-based (CT) computer navigation [27–29]. Twelve were eliminated for pseudorandomization or a lack of response to our request for clarification of randomization method [16–18,30–38]. Three papers were eliminated due to redundant data from a study already included in our analysis [39–41].
Computer navigation in total knee arthroplasty (TKA) is intended to produce more reliable results, but its impact on functional outcomes has not been firmly demonstrated. Literature searches were performed for Level I randomized trials that compared TKA using imageless computer navigation to those performed with conventional instruments. Radiographic and functional outcomes were extracted and statistically analyzed. TKA performed with computer navigation was more likely to be within 3° of ideal mechanical alignment (87.1% vs. 73.7%, P<.01). Navigated TKAs had a higher increase in Knee Society Score at 3-month follow-up (68.5 vs. 58.1, P=.03) and at 12–32month follow-up (53.1 vs. 45.8, P<.01). Computer navigation in TKA provides more accurate alignment and superior functional outcomes at short-term follow-up.
- Meta-Analysis of Navigation vs Conventional Total Knee Arthroplasty
2012, Journal of Arthroplasty
After application of exclusion criteria and removal of duplicate titles, 27 RCTs were assessed, of which 2 studies were excluded because of lack of relevance and a further 2 were excluded because they were meta-analyses. Of these 23 studies [7,17-38], 20 were in the English language, 1 was in French, and 2 were in German. In total, 2541 patients were included, of which 1374 patients were treated with navigation-assisted TKA and 1302 were of the conventional group.
Navigated total knee arthroplasty (TKA) is promoted as a means to improve limb and prosthesis alignment. This study involved a systematic review and meta-analysis for all randomized controlled trials in the literature from 1986 to 2009 comparing alignment outcomes between navigated and conventional TKA. Alignment outcomes were pooled using a random-effects model, and heterogeneity was explored. Twenty-three randomized controlled trials were identified comparing navigated vs conventional TKA involving 2541 patients. Patients who underwent navigated TKA had a significantly lower risk of implant malalignment at more than 3° as well as more than 2°. In addition, the risk of malalignment was reduced for the coronal plane tibial and femoral components as well as femoral and tibial slope. This meta-analysis demonstrates that navigated TKA provides significant improvement in prosthesis alignment.
- Meta-Analysis of Alignment Outcomes in Computer-Assisted Total Knee Arthroplasty Surgery
2007, Journal of Arthroplasty
Computer-assisted surgery (CAS) has been advocated as a means to improve limb and prosthesis alignment and assist in ligament balancing in total knee arthroplasty (TKA). Thus, we sought to examine alignment outcomes in CAS vs conventional TKA. A systematic review of literature from 1990 to 2007 was performed. Direct comparison of alignment outcomes was performed using random effects meta-analyses. Twenty-nine studies of CAS vs conventional TKA were identified, and included mechanical axis malalignment of greater than 3° occurred in 9.0% of CAS vs 31.8% of conventional TKA patients. The risk of greater than 3° malalignment was significantly less with CAS than conventional techniques for mechanical axis and frontal plane femoral and tibial component alignment. Tibial and femoral slope both showed statistical significance in favor of CAS at greater than 2° malalignment. Meta-analysis of alignment outcomes for CAS vs conventional TKA indicates significant improvement in component orientation and mechanical axis when CAS is used.
- (iv) Computer-assisted knee replacement techniques
2007, Current Orthopaedics(Video) Computer Assisted Navigation for Total Knee Replacement
Implant alignment errors are associated with inferior results after total knee arthroplasty. Computer assistance supplements mechanical instrumentation by the addition of measurements which are used to locate landmarks, direct surgical tools and thereby better align prosthetic components. Modern navigation systems are based on infrared-light tracking or, more recently, on electromagnetic guidance. After initial scepticism a variety of systems have found acceptance and a remarkable number of clinical and laboratory studies have been published. There appears to be a consensus that computer assistance brings about a significant reduction in the number of outliers and improved varus/valgus, rotation and slope alignment of components. Most studies conclude with the prediction that individual and cumulative improvement in component alignment will ultimately lead to better long-term results. The controversies surrounding routine use of computer assistance in knee arthroplasy are discussed. Data analysis founded on navigated dynamic intra-operative investigation will possibly be the key to future implant design and alignment.
- A Cadaveric Study to Assess the Accuracy of Computer-Assisted Surgery in Locating the Hip Center During Total Knee Arthroplasty
2007, Journal of Arthroplasty
We found that, first, high hip circle rotation gives better accuracy and precision than small hip circle rotation and that, second, 75% of results had a margin of error of less than 1°, 95% of the results had a margin of error less than 1.5°, and 100% had a error inferior to 2° (1.91°). Technique B, using only 1 tracker in the femur, was as accurate as technique A, which needs 2 trackers around the hip joint . There was no statistical difference between techniques A and B, nor between the intra- and inter-observer analyses.
Computer-assisted technology allows the accurate location of inaccessible landmarks such as the center of the hip in total hip arthroplasty. Using 7 fresh normal cadaveric hips, we conducted 2 studies. The first study compared iliac (A) vs no iliac (B) tracking. The second study assessed the reliability of the hip center acquisition using the range of hip motion during manipulation. The first study revealed no statistical difference between the 2 techniques A (mean, 0.67; SD, 0.15) and B (mean, 0.66; SD, 0.32) used to locate the center of the hip. In the second study, a range of motion less than 10° negatively affected accuracy. Using this technology, without an iliac tracker, allows accurate and precise determination of the center of the hip.
Research articleChance and challenge of associating liver partition and portal vein ligation for staged hepatectomy
Hepatobiliary & Pancreatic Diseases International, Volume 18, Issue 3, 2019, pp. 214-222
The associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) was first performed in 2007. The critical patient selection, timing to perform the second stage operation, and minimally invasive technique are three key factors for patient outcomes. The aim of this review is to summarize published data on these three aspects.
Studies were identified by searching PubMed for articles published from January 2007 to October 2018, using the keywords “associating liver partition and portal vein ligation for staged hepatectomy” or “ALPPS” or “in situ split”. Studies on colorectal liver metastasis (CRLM), perihilar cholangiocarcinoma (PHC), and hepatocellular carcinoma (HCC) indicated for ALPPS, cutoff values to determine the timing of stage 2, as well as modifications of ALPPS were included.
The mortality of ALPPS for CRLM is declining, for PHC is high. In patients with HCC, essential hypertrophy makes the ALPPS safer. However, the degrees of fibrosis affect the hypertrophy. The future liver remnant volume is still the gold standard to start the second stage. Hepatobiliary scintigraphy plays an important role in quantitatively assessing liver function, whereas cutoff values need to be further calibrated. Less-invasive ALPPS modifications have increased and led to a decreased mortality.
ALLPS improved the CRLM outcomes; ALPPS is feasible in patients with PHC after failure of portal vein embolization; ALPPS may be an option for HCC patients with major vascular invasion and thrombosis. The simplified and less-invasive ALPPS is the trend.
Research articleDirect, Cementless, Metaphyseal Fixation in Knee Revision Arthroplasty With Sleeves—Short-Term Results
The Journal of Arthroplasty, Volume 30, Issue 12, 2015, pp. 2256-2259(Video) Computer Assisted Total Knee Arthroplasty Brief
Different options for implant fixation in revision TKA exist. Small series have been published on direct cementless fixation with sleeves. The objective of this study was to analyze the short- and mid-term results of sleeve-fixation in a large revision TKA series. In this prospective study 121 patients with 193 sleeves (119 tibial and 74 femoral) were included. Mean follow-up was 3.6years (2–6.1years). Analysis included clinical and radiographic assessment. ROM, KSS and Functional Score improved significantly. Fourteen patients (11.4%) underwent operative re-revision during the follow-up period. Direct cementless fixation in the metaphysis by sleeves is a promising option for implant fixation in revision TKA, both on the tibial and femoral side.
Research articleThe emulsion crystallization of hydrogenated castor oil into long thin fibers
Journal of Crystal Growth, Volume 383, 2013, pp. 51-56
The present study discusses the optimal crystal growth conditions required for the emulsion crystallization of hydrogenated castor oil (HCO) into several crystal morphologies. The best possible crystal shape is furthermore identified in case high rheology modifying performance is required. HCO was crystallized in a meso- and micro-continuous process which allowed for a controlled and fast screening of several crystal morphologies at different crystallization conditions. Applying high isothermal temperatures (above 55°C) resulted in a combination of rosettes, thick fibers and thin fibers. At lower isothermal temperatures (below 55°C) the shape gradually evolved to a combination of short needles, spherically shaped and/or irregularly shaped crystals. Crystals with the highest aspect ratio were obtained when crystals were grown between 30°C and 45°C and were subsequently reheated above 63°C, forming high amounts of large thin fibrous crystals. When diluted to 0.25wt% these fibrous crystals increased the low shear viscosity far better compared to the other crystal shapes.
Research articleWhat's brought along and brought about: Negotiating writing practices in two high school classrooms
Learning, Culture and Social Interaction, Volume 24, 2020, Article 100291
This article presents two studies of students and teachers negotiating writing practices in two high school English classrooms in the United States. Both studies draw on a sociocultural framework of understanding writing as a social practice involving distributed, mediated, and dialogic processes of invention. Each study presents a different approach to investigating how writing practices are negotiated and how writing is produced related to that negotiation. Across the two studies, findings illustrate how the written texts students produce are a result of negotiations among historical writing practices students bring along, the sanctioned writing practices the teacher is attempting to bring about, and a myriad of other possible related issues. Considered together, the findings of the two studies have implications for understanding student writing as a negotiated relationship among multiple writing practices, social interactions with peers and teachers, and objects and artifacts at work within the writing events.
Research articleClinical significance of somatic mutation in unexplained blood cytopenia
Blood, Volume 129, Issue 25, 2017, pp. 3371-3378
Unexplained blood cytopenias, in particular anemia, are often found in older persons. The relationship between these cytopenias and myeloid neoplasms like myelodysplastic syndromes is currently poorly defined. We studied a prospective cohort of patients with unexplained cytopenia with the aim to estimate the predictive value of somatic mutations for identifying subjects with, or at risk of, developing a myeloid neoplasm. The study included a learning cohort of 683 consecutive patients investigated for unexplained cytopenia, and a validation cohort of 190 patients referred for suspected myeloid neoplasm. Using granulocyte DNA, we looked for somatic mutations in 40 genes that are recurrently mutated in myeloid malignancies. Overall, 435/683 patients carried a somatic mutation in at least 1 of these genes. Carrying a somatic mutation with a variant allele frequency ≥0.10, or carrying 2 or more mutations, had a positive predictive value for diagnosis of myeloid neoplasm equal to 0.86 and 0.88, respectively. Spliceosome gene mutations and comutation patterns involving TET2, DNMT3A, or ASXL1 had positive predictive values for myeloid neoplasm ranging from 0.86 to 1.0. Within subjects with inconclusive diagnostic findings, carrying 1 or more somatic mutations was associated with a high probability of developing a myeloid neoplasm during follow-up (hazard ratio = 13.9, P < .001). The predictive values of mutation analysis were confirmed in the independent validation cohort. The findings of this study indicate that mutation analysis on peripheral blood granulocytes may significantly improve the current diagnostic approach to unexplained cytopenia and more generally the diagnostic accuracy of myeloid neoplasms.
Research articleSoft Tissue Balance in Total Knee Arthroplasty with a Force Sensor
Orthopedic Clinics of North America, Volume 45, Issue 2, 2014, pp. 175-184(Video) Computer Assisted Surgery (CAS) for Total Knee Replacement
Copyright © 2000 Published by Elsevier Inc.