Patients with metastatic prostate cancer are more likely than other groups to present for radiopharmaceutical therapy with urinary incontinence due to complications from prior local prostate cancer ...treatment. A consequence of urinary incontinence in patients receiving radiopharmaceutical therapy is the potential production of contaminated solid waste, which must be managed by the licensee and, at home, managed by and disposed of by the patient. Prolonging the patient stay in the treating facility after radiopharmaceutical therapy administration, until the first urinary void or potentially overnight, may moderately reduce the quantity of contaminated waste being managed by the patient at home. However, this approach does not fully mitigate the need for a patient waste-management strategy. In this brief communication, the relative radiation safety merits of contaminated waste disposal in the normal household waste stream in comparison to other waste management strategies are evaluated.
Our research focuses on the storage decision in a semi‐automated storage system, where the inventory is stored on mobile storage pods. In a typical system, each storage pod carries a mixture of ...items, and the inventory of each item is spread over multiple storage pods. These pods are transported by robotic drives to stationary stations on the boundary of the storage zone where associates conduct pick or stow operations. The storage decision is to decide to which storage location within the storage zone to return a pod upon the completion of a pick or stow operation. The storage decision has a direct impact on the total travel time and hence the workload of the robotic drives. We develop a fluid model to analyze the performance of velocity‐based storage policies. We characterize the maximum possible improvement from applying a velocity‐based storage policy in comparison to the random storage policy. We show that class‐based storage with two or three classes can achieve most of the potential benefits and that these benefits increase with greater variation in the pod velocities. To validate the findings, we build a discrete‐time simulator with real industry data. We observe an 8% to 10% reduction in the travel distance with a 2‐class or 3‐class storage policy, depending on the parameter settings. From a sensitivity analysis, we establish the robustness of the class‐based storage policies as they continue to perform well under a broad range of warehouse settings, including different zoning strategies, resource utilization, and space utilization levels.
How to think about planned lead times Graves, Stephen C.
International journal of production research,
01/2022, Volume:
60, Issue:
1
Journal Article
Peer reviewed
A fundamental construct of most planning systems is the planned lead time. A planned lead time is a control parameter that refers to the planned amount of time for a production, transportation or ...replenishment activity. The intent of this article is to provide a brief, critical examination of planned lead times. We first discuss why planned lead times are used and why they are important. We then discuss the trade-offs to be considered in setting the planned lead times. We follow this with a review of the research literature on how to specify the planned lead times. Finally, we offer a simple model to provide some insight on how the planned lead time for an activity depends on the stochastic variability of the resource requirements for the activity, and on the flexibility and utilisation of the resource associated with the activity.
Computer navigation for total knee arthroplasty has improved alignment compared with that resulting from non-navigated total knee arthroplasty. This study analyzed data from the Australian ...Orthopaedic Association National Joint Replacement Registry to examine the effect of computer navigation on the rate of revision of primary total knee arthroplasty.
The cumulative percent revision following all non-navigated and navigated primary total knee arthroplasties performed in Australia from January 1, 2003, to December 31, 2012, was assessed. In addition, the type of and reason for revision as well as the effect of age, surgeon volume, and use of cement for the prosthesis were examined. Kaplan-Meier estimates of survivorship were used to describe the time to first revision. Hazard ratios (HRs) from Cox proportional hazards models, with adjustment for age and sex, were used to compare revision rates.
Computer navigation was used in 44,573 (14.1% of all) primary total knee arthroplasties, and the rate of its use increased from 2.4% in 2003 to 22.8% in 2012. Overall, the cumulative percent revision following non-navigated total knee arthroplasty at nine years was 5.2% (95% confidence interval CI = 5.1 to 5.4) compared with 4.6% (95% CI = 4.2 to 5.1) for computer-navigated total knee arthroplasty (HR = 1.05 95% CI = 0.98 to 1.12, p = 0.15). There was a significant difference in the rate of revision following non-navigated total knee arthroplasty compared with that following navigated total knee arthroplasty for younger patients (HR = 1.13 95% CI = 1.03 to 1.25, p = 0.011). Patients less than sixty-five years of age who had undergone non-navigated total knee arthroplasty had a cumulative percent revision of 7.8% (95% CI = 7.5 to 8.2) at nine years compared with 6.3% (95% CI = 5.5 to 7.3) for those who had undergone navigated total knee arthroplasty. Computer navigation led to a significant reduction in the rate of revision due to loosening/lysis (HR = 1.38 95% CI = 1.13 to 1.67, p = 0.001), which is the most common reason for revision of total knee arthroplasty.
Computer navigation reduced the overall rate of revision and the rate revision for loosening/lysis following total knee arthroplasty in patients less than sixty-five years of age.
Summary
Tick bites in Australia can lead to a variety of illnesses in patients. These include infection, allergies, paralysis, autoimmune disease, post‐infection fatigue and Australian multisystem ...disorder.
Rickettsial (Rickettsia spp.) infections (Queensland tick typhus, Flinders Island spotted fever and Australian spotted fever) and Q fever (Coxiella burnetii) are the only systemic bacterial infections that are known to be transmitted by tick bites in Australia.
Three species of local ticks transmit bacterial infection following a tick bite:
►the paralysis tick (Ixodes holocyclus) is endemic on the east coast of Australia and causes Queensland tick typhus due to R. australis and Q fever due to C. burnetii;
►the ornate kangaroo tick (Amblyomma triguttatum) occurs throughout much of northern, central and western Australia and causes Q fever; and
►the southern reptile tick (Bothriocroton hydrosauri) is found mainly in south‐eastern Australia and causes Flinders Island spotted fever due to R. honei.
Much about Australian ticks and the medical outcomes following tick bites remains unknown. Further research is required to increase understanding of these areas.
There is ongoing debate concerning the best method of femoral fixation in older patients receiving primary THA. Clinical studies have shown high survivorship for cemented and cementless femoral ...stems. Arthroplasty registry studies, however, have universally shown that cementless stems are associated with a higher rate of revision in this patient population. It is unclear if the difference in revision rate is a reflection of the range of implants being used for these procedures rather than the mode of fixation.
(1) Is the risk of revision higher in patients older than 75 years of age who receive one of the three cementless stems with the highest overall survivorship in the registry than in those of that age who received one of the three best-performing cemented stems? If so, is there a difference in risk of early revision versus late revision, defined as revision within 1 month after index surgery? (2) Are there any diagnoses (such as osteoarthritis OA or femoral neck hip fracture) in which the three best-performing cementless stems had better survivorship than one of the three best-performing cementless stems? (3) Do these findings change when evaluated by patient sex?
The Australian Orthopaedic Association National Joint Replacement Registry data were used to identify the best three cemented and the best three cementless femoral stems. The criteria for selection were the lowest 10-year revision rate and use in > 1000 procedures in this age group of patients regardless of primary diagnosis. The outcome measure was time to first revision using Kaplan-Meier estimates of survivorship. Comparisons were made for THAs done for any reason and then specifically for OA and femoral neck fracture separately.
Overall, the cumulative percent revision in the first 3 months postoperatively was lower among those treated with one of the three best-performing cemented stems than those treated with one of the three best-performing cementless stems (hazard ratio HR for best three cementless versus best three cemented = 3.47 95% confidence interval {CI}, 1.60-7.53, p = 0.001). Early revision was 9.14 times more common in the best three cementless stems than in the best three cemented stems (95% CI, 5.54-15.06, p = 0.001). Likewise, among patients with OA and femoral neck fracture, the cumulative percent revision was consistently higher at 1 month postoperatively among those treated with one of the three best-performing cementless stems than those treated with one of the three best-performing cementless stems (OA: HR for best three cementless versus best three cemented = 8.82 95% CI, 5.08-15.31, p < 0.001; hip fracture: HR for best 3 cementless versus best three cemented = 27.78 95% CI, 1.39-143.3, p < 0.001). Overall, the cumulative percent revision was lower in the three best cemented stem group than the three best cementless stem group for both males and females at 1 month postoperatively (male: HR = 0.42 95% CI, 0.20-0.92, p = 0.030; female: HR = 0.06 95% CI, 0.03-0.10, p < 0.001) and for females at 3 months postoperatively (HR = 0.15 95% CI, 0.06-0.33, p < 0.001), after which there was no difference.
Cementless femoral stem fixation in patients 75 years or older is associated with a higher early rate of revision, even when only the best-performing prostheses used in patients in this age group were compared. Based on this review of registry data, it would seem important to ensure the proper training of contemporary cementing techniques for the next generation of arthroplasty surgeons so they are able to use this option when required. However, the absence of a difference in the two groups undergoing THA after 3 months suggests that there can be a role for cementless implants in selected cases, depending on the surgeon's expertise and the quality and shape of the proximal femoral bone.
Level III, therapeutic study.
Studies have identified increased cancer risk among patients undergoing total hip arthroplasty (THA) compared to the general population. However, evidence of all-cause and site-specific cancer risk ...associated with different bearing surfaces has varied, with previous studies having short latency periods with respect to use of modern Metal-on-Metal (MoM) bearings. Using the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) linked to Australasian Association of Cancer Registries data, our aim was to evaluate risk of all-cause and site-specific cancer according to bearing surfaces in patients undergoing THA for osteoarthritis and whether risk increased with MoM bearings.
Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated by comparing number of observed cancer cases to expected number based on incidence rate in the Australian population. All-cause and site-specific cancer rates were calculated for all conventional stemmed THA (csTHA) and resurfacing THA (rsTHA) procedures performed for osteoarthritis. Cox proportional hazards models were used to compare cancer rates for MoM, ceramic-on-ceramic (CoC) and resurfacing procedures with a comparison group comprising metal-on-polyethylene (MoP) or ceramic-on-polyethylene (CoP) procedures.
There were 156,516 patients with csTHA procedures and 11,321 with rsTHA procedures for osteoarthritis performed between 1999 and 2012. Incidence of all-cause cancer was significantly higher for csTHA (SIR 1.24, 95% CI 1.22-1.26) and rsTHA (SIR 1.74, 95% CI 1.39-2.04) compared to the Australian population. For csTHA, there was no significant difference in all-site cancer rates for MoM (Hazard Ratio (HR) 1.01, 95%CI 0.96-1.07) or CoC (HR 0.98, 95%CI 0.94-1.02) compared to MoP and CoP bearings. Significantly increased risk of melanoma, non-Hodgkins lymphoma, myeloma, leukaemia, prostate, colon, bladder and kidney cancer was found for csTHA and, prostate cancer, melanoma for rsTHA procedures when compared to the Australian population, although risk was not significantly different across bearing surfaces.
csTHA and rsTHA procedures were associated with increased cancer incidence compared to the Australian population. However, no excess risk was observed for MoM or CoC procedures compared to other bearing surfaces.
Background Patient-reported outcome measures (PROMs) are commonly used to evaluate surgical outcome in patients undergoing joint replacement surgery, however routine collection from the target ...population is often incomplete. Representative samples are required to allow inference from the sample to the population. Although higher capture rates are desired, the extent to which this improves the representativeness of the sample is not known. We aimed to measure the representativeness of data collected using an electronic PROMs capture system with or without telephone call follow up, and any differences in PROMS reporting between electronic and telephone call follow up. Methods Data from a pilot PROMs program within a large national joint replacement registry were examined. Telephone call follow up was used for people that failed to respond electronically. Data were collected pre-operatively and at 6 months post-operatively. Responding groups (either electronic only or electronic plus telephone call follow up) were compared to non-responders based on patient characteristics (joint replaced, bilaterality, age, sex, American Society of Anesthesiologist (ASA) score and Body Mass Index (BMI)) using chi squared test or ANOVA, and PROMs for the two responder groups were compared using generalised linear models adjusted for age and sex. The analysis was restricted to those undergoing primary elective hip, knee or shoulder replacement for osteoarthritis. Results Pre-operatively, 73.2% of patients responded electronically and telephone follow-up of non-responders increased this to 91.4%. Pre-operatively, patients responding electronically, compared to all others, were on average younger, more likely to be female, and healthier (lower ASA score). Similar differences were found when telephone follow up was included in the responding group. There were little (if any) differences in the post-operative comparisons, where electronic responders were on average one year younger and were more likely to have a lower ASA score compared to those not responding electronically, but there was no significant difference in sex or BMI. PROMs were similar between those reporting electronically and those reporting by telephone. Conclusion Patients undergoing total joint replacement who provide direct electronic PROMs data are younger, healthier and more likely to be female than non-responders, but these differences are small, particularly for post-operative data collection. The addition of telephone call follow up to electronic contact does not provide a more representative sample. Electronic-only follow up of patients undergoing joint replacement provides a satisfactory representation of the population invited to participate.
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