The learning curve has been established for robotic-assisted total knee arthroplasty (RATKA) during the first month of use; however, there have been no studies evaluating this on a longer term. ...Therefore, the purpose of this study was to compare operative times for three cohorts during the first year following adoption of RATKA (initial, 6 months, and 1 year) and a prior cohort of manual TKA. We investigated both mean operative times and the variability of operative time in each cohort. This is a learning curve study comparing a single surgeon's experience using RAKTA. The study groups were made up of two cohorts of 60 cementless RATKAs performed at ∼6 months and 1 year of use. A learning curve was created based on the mean operative times and individual operative times were stratified into different cohorts for comparison. Study groups were compared with the surgeon's initial group of 20 cemented RATKAs and 60 cementless manual cases. Descriptive numbers were compiled and mean operative times were compared using Student's
-tests for significant differences with a
-value of < 0.05. The mean surgical times continued to decrease after 6 months of RATKA. In 1 year, the surgeon was performing 88% of the RATKA between 50 and 69 minutes. The initial cohort and 1-year robotic-assisted mean operative times were 81 and 62 minutes, respectively (
< 0.00001). Mean 6-month robotic-assisted operative times were similar to manual times (
= 0.12). A significant lower time was found between the mean operative times for the 1-year robotic-assisted and manual (
= 0.008) TKAs. The data show continued improvement of operative times at 6 months and 1 year when using this new technology. The results of this study are important because they demonstrate how the complexity of a technology which initially increases operative time can be overcome and become more time-effective than conventional techniques.
Predictive models help determine predictive factors necessary to improve functional outcomes after total knee arthroplasty (TKA). However, no study has assessed predictive models for functional ...outcomes after TKA based on the new concepts of personalised surgery and new technologies. This study aimed to develop and evaluate predictive modelling approaches to predict the achievement of minimal clinically important difference (MCID) in patient-reported outcome measures (PROMs) 1 year after TKA.
Four hundred thirty robotic-assisted TKAs were analysed in this retrospective study. The mean age was 67.9 ± 7.9 years; the mean body mass index (BMI) was 32.0 ± 6.8 kg/m
. The following PROMs were collected preoperatively and 1-year postoperatively: knee injury and osteoarthritis outcome score for joint replacement, Western Ontario and McMaster Universities osteoarthritis index (WOMAC) Function, WOMAC Pain. Demographic data, preoperative CT scan, implant size, implant position on the robotic system and characteristics of the joint replacement procedure were selected as predictive variables. Four machine learning algorithms were trained to predict the MCID status at 1-year post-TKA for each PROM survey. 'No MCID' was chosen as the target. Models were evaluated by class discrimination (F1-score) and area under the receiver operating characteristic curve (ROC-AUC).
The best-performing model was ridge logistic regression for WOMAC Function (area under the curve AUC = 0.80, F1 = 0.48, sensitivity = 0.79, specificity = 0.62). Variables most strongly contributing to not achieving MCID status were preoperative PROMs, high BMI and femoral resection depth (posterior and distal), supporting functional positioning principles. Conversely, variables contributing to a positive outcome (achieving MCID) were medial/lateral alignment of the tibial component, whether the procedure was an outpatient surgery and whether the patient received managed Medicare insurance.
The most predictive variables included preoperative PROMs, BMI and surgical planning. The surgical predictive variables were valgus femoral alignment and femoral rotation, reflecting the benefits of personalised surgery. Including surgical variables in predictive models for functional outcomes after TKA should guide clinical and surgical decision-making for every patient.
Level III.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
As with most new surgical technologies, there is an associated learning curve with robotic-assisted total knee arthroplasty (TKA) before surgeons can expect ease of use to be similar to that of ...manual cases. Therefore, the purpose of this study was to (1) assess robotic-assisted versus manual operative times of two joint reconstructive surgeons separately as well as (2) find an overall learning curve. A total of 240 robotic-assisted TKAs performed by two board-certified surgeons were analyzed. The cases were sequentially grouped into 20 cases and a learning curve was created based on mean operative times. For each surgeon, mean operative times for their first 20 and last 20 robotic-assisted cases were compared with 20 randomly selected manual cases performed by that surgeon as controls prior to the initiation of the robotic-assisted cases. Each of the surgeons first 20 robotic assisted, last 20 robotic assisted, and 20 controls were then combined to create 3 cohorts of 40 cases for analysis.
: First and last robotic cohort operative times were 81 and 70 minutes (
< 0.05). Mean operative times for the first 20 robotic-assisted cases and manual cases were 81 versus 68 minutes (
< 0.05). Mean operative times for the last 20 robotic-assisted cases and manual cases were 70 versus 68 minutes (
> 0.05).
: First and last robotic cohort operative times were 117 and 98 minutes (
< 0.05). Mean operative times for the first 20 robotic-assisted cases and manual cases were 117 versus 95 (
< 0.05). Mean operative times for the last 20 robotic-cohort cases and manual cases were 98 versus 95 (
> 0.05). A similar trend occurred when the times of two surgeons were combined. The data from this study effectively create a learning curve for the use of robotic-assisted TKA. As both surgeons completed their total cases numbers within similar time frames, these data imply that within a few months, a board-certified orthopaedic joint arthroplasty surgeon should be able to adequately perform robotic TKA without adding any operative times.
Aims
The aim of this study was to report patient and clinical outcomes following robotic-assisted total knee arthroplasty (RA-TKA) at multiple institutions with a minimum two-year follow-up.
Methods
...This was a multicentre registry study from October 2016 to June 2021 that included 861 primary RA-TKA patients who completed at least one pre- and postoperative patient-reported outcome measure (PROM) questionnaire, including Forgotten Joint Score (FJS), Knee Injury and Osteoarthritis Outcomes Score for Joint Replacement (KOOS JR), and pain out of 100 points. The mean age was 67 years (35 to 86), 452 were male (53%), mean BMI was 31.5 kg/m
2
(19 to 58), and 553 (64%) cemented and 308 (36%) cementless implants.
Results
There were significant improvements in PROMs over time between preoperative, one- to two-year, and > two-year follow-up, with a mean FJS of 17.5 (SD 18.2), 70.2 (SD 27.8), and 76.7 (SD 25.8; p < 0.001); mean KOOS JR of 51.6 (SD 11.5), 85.1 (SD 13.8), and 87.9 (SD 13.0; p < 0.001); and mean pain scores of 65.7 (SD 20.4), 13.0 (SD 19.1), and 11.3 (SD 19.9; p < 0.001), respectively. There were eight superficial infections (0.9%) and four revisions (0.5%).
Conclusion
RA-TKA demonstrated consistent clinical results across multiple institutions with excellent PROMs that continued to improve over time. With the ability to achieve target alignment in the coronal, axial, and sagittal planes and provide intraoperative real-time data to obtain balanced gaps, RA-TKA demonstrated excellent clinical outcomes and PROMs in this patient population. Cite this article: Bone Jt Open 2022;3(7):589–595.
Although there are many studies on the alignment advantages when using the robotic arm-assisted (RAA) system for total knee arthroplasty (TKA), there have been questions regarding patient-reported ...outcomes. Therefore, the purpose of this study was to use this index to compare: (1) total, (2) physical function, and (3) pain scores for manual versus RAA patients. We compared 53 consecutive RAA to 53 consecutive manual TKAs. No differences in preoperative scores were found between the cohorts. Patients were administered a modified Western Ontario and McMaster Universities Osteoarthritis Index satisfaction survey preoperatively and at 1-year postoperatively. The results were broken down to: (1) total, (2) physical function, and (3) pain scores. Univariate analysis with independent samples
-tests was used to compare 1-year postoperative scores. Multivariate models with stepwise backward linear regression were utilized to evaluate the associations between scores and surgical technique, age, sex, as well as body mass index (BMI). Statistical analyses were performed with a
< 0.05 to determine significance. The RAA cohort had significantly improved mean total (6 ± 6 vs. 9 ± 8 points,
= 0.03) and physical function scores (4 ± 4 vs. 6 ± 5 points,
= 0.02) when compared with the manual cohort. The mean pain score for the RAA cohort (2 ± 3 points range, 0-14 points) was also lower than that for the manual cohort (3 ± 4 points range, 0-11 points) (
= 0.06). On backward linear regression analyses, RAA was found to be significantly associated with more improved total (β coefficient β -0.208, standard error SE 1.401,
< 0.05), function (β = 0.216, SE = 0.829,
< 0.05), and pain scores (β -0.181, SE = 0.623,
= 0.063). The RAA technique was found to have the strongest association with improved scores when compared with age, gender, and BMI. This study suggests that RAA patients may have short-term improvements at minimum 1-year postoperatively. However, longer term follow-up with greater sample sizes is needed to further validate these results.
Background: To examine whether SMOFlipid prevents progression of intestinal failure–associated liver disease (IFALD) in parenteral nutrition (PN)–dependent infants with early IFALD (conjugated ...bilirubin 17–50 µmol/L, 1-3 mg/dL). Study Design: Pilot multicenter blinded randomized controlled trial comparing SMOFlipid with Intralipid. Patients received the trial lipid for up to 12 weeks, unless they achieved full enteral tolerance sooner. The primary clinical outcome was the serum conjugated bilirubin. Results: Twenty-four infants (mean age, 6 weeks) participated in the trial (13 Intralipid and 11 SMOFlipid). At the time of trial enrollment, patients in both groups were receiving 90% of their calories by PN. Mean duration on trial was 8 weeks and did not differ according to treatment (P = .99). At trial conclusion, patients who received SMOFlipid had a lower conjugated bilirubin than those who received Intralipid (mean difference, –59 µmol/L; P = .03). Patients receiving SMOFlipid were also more likely to have a decrease in serum conjugated bilirubin to 0 µmol/L than those in the Intralipid group over the entire observation period (hazard ratio, 10.6; 95%; P = .03). The time to achievement of full enteral tolerance did not differ statistically (hazard ratio, 1.3; P = .59) between the groups. There was no significant difference in safety outcomes between the groups. Conclusions: Compared with Intralipid, SMOFlipid reduces the risk of progressive IFALD in children with intestinal failure. This trial was registered at clinicaltrials.gov as NCT00793195.
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Advanced imaging used in robotic-assisted total knee arthroplasty (TKA), such as computed tomography (CT)-based three-dimensional (3D) planning, may provide an accurate means of implant sizing ...preoperatively. The purpose of this study was to examine preoperative CT-based implant planning accuracy for robotic-assisted TKA in patients who have (1) varus deformities, (2) valgus deformities, (3) neutral alignment, and (4) retained hardware. A total of 393 patients underwent a robotic-assisted TKA by a single surgeon received preoperative CT scans. The surgeon reviewed the CT-based model preoperatively and recorded the expected size of the components. The final implants used in each case were recorded and compared with the surgeon's preoperative plan. In all groups of patients, the surgeon's CT-based implant plan was within one size of the implant utilized 100% of the time for both the tibiae and femora. Overall, the surgeon was exactly matched in 319 (81%) and 315 (80%) cases for the femoral and tibial components, respectively. For the femoral component, the mean age for patients in whom the original plan was exactly matched was younger than those whose implants were upsized and older than patients those implants were downsized (
= 0.024). Other patient demographics and preoperative knee alignment were not associated with predictive accuracy for femoral or tibial components. Our results demonstrate how preoperative CT-based, 3D planning for robotic-assisted TKA is accurate to within one size of the components in every case (100%), and exactly matched in 80%. The results of this study are important because they demonstrate how CT-based preoperative implant planning for TKA is reliable and accurate across all native knee alignments and other patient-specific factors. In addition, they build on a previous study by the same single surgeon, demonstrating that predictive ability can improve over time. This may be important as we move toward more outpatient surgery with less ability for prostheses inventory at ambulatory sites.
Robotic-assisted total knee arthroplasty (RA-TKA) has been shown to improve the accuracy of bone resection, reduce radiographic outliers, and decrease iatrogenic injury. However, it has also been ...shown that RA-TKA surgical times can be longer than manual surgery during adoption. The purpose of this article was to investigate (1) the characteristics of the operative time curves and trends, noting the amount of surgeons who improved, for those who performed at least 12 cases (based on initial modeling); (2) the proportion of RA surgeons who achieved the same operative times for RA-TKA as compared with manual TKAs; and (3) the number of RA-TKA cases until a steady-state operative time was achieved. TKA operative times were collected from 30 hospitals for 146 surgeons between January 1, 2016, and December 31, 2019. A hierarchical Bayesian model was used to estimate the difference between the mean RA-TKA times by case interval and the weighted baseline for manual times. The learning curve was observed at the 12th case. Therefore, operative times were analyzed for each surgeon who performed at least 12 RA-TKA cases to determine the percentage of these surgeons who trended toward a decrease or increase in their times. These surgeons were further analyzed to determine the proportion who achieved the same operating times as manual TKAs. A further hierarchical Bayesian model was used to determine when these surgeons achieved steady-state operative times. There were 60 surgeons (82%) who had decreasing surgical times over the first 12 RA-TKA cases. The remaining 13 (18%) had increasing surgical times (mean increase of 0.59 minutes/case). Approximately two-thirds of the surgeons (64%) achieved the same operating times as manual cases. The steady-state time neutrality occurred between 15 and 20 cases and beyond. This study demonstrated the learning curve for a large cohort of RA-TKAs. This model demonstrated a learning curve between 15 and 20 cases and beyond. These are important findings for this innovative technology.
Crystal Structure of Arp2/3 Complex Robinson, Robert C.; Turbedsky, Kirsi; Kaiser, Donald A. ...
Science (American Association for the Advancement of Science),
11/2001, Volume:
294, Issue:
5547
Journal Article
Peer reviewed
We determined a crystal structure of bovine Arp2/3 complex, an assembly of seven proteins that initiates actin polymerization in eukaryotic cells, at 2.0 angstrom resolution. Actin-related protein 2 ...(Arp2) and Arp3 are folded like actin, with distinctive surface features. Subunits ARPC2 p34 and ARPC4 p20 in the core of the complex associate through long carboxyl-terminal α helices and have similarly folded amino-terminal α/β domains. ARPC1 p40 is a seven-blade β propeller with an insertion that may associate with the side of an actin filament. ARPC3 p21 and ARPC5 p16 are globular α-helical subunits. We predict that WASp/Scar proteins activate Arp2/3 complex by bringing Arp2 into proximity with Arp3 for nucleation of a branch on the side of a preexisting actin filament.
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