Cemented total hip replacement in patients under 55 years:Good results in 104 hips followed up for ≥22 years

Background and purpose — About 86,000 total hip replacements (THR) have been registered in patients under 55 years in the National Joint Registry of England and Wales (NJR). The use of uncemented implants has increased, despite their outcomes not having been proven to be significantly better than cemented implants in this registry. We determined the implant survivorship and functional outcomes of cemented THR in patients under 55 years at a minimum follow-up of 22 years. Patients and methods — 104 hips in 100 patients were included in this prospective study. Functional outcome was assessed using the Harris Hip Score and radiographs were assessed for implant failure and “at risk” of failure. Kaplan–Meier survivorship analysis was performed. Results — 89% of hips showed good to excellent results at final follow-up with a mean Harris Hip Score of 88 at a mean follow-up of 25 years. Revision was performed in 3/104 hips. 14 acetabular components and 4 femoral components were “at risk” of failure. The survivorship at minimum 22 years with revision for any reason as the end-point was 97% (95% CI 95–98). Interpretation — Cemented hip replacements perform well in young patients with good long-term functional and radiographic outcomes

Dynamically mapping tasks with priorities and multiple deadlines in a heterogeneous environment

Includes bibliographical references (pages 166-167).In a distributed heterogeneous computing system, the resources have different capabilities and tasks have different requirements. To maximize the performance of the system, it is essential to assign the resources to tasks (match) and order the execution of tasks on each resource (schedule) to exploit the heterogeneity of the resources and tasks. Dynamic mapping (defined as matching and scheduling) is performed when the arrival of tasks is not known a priori. In the heterogeneous environment considered in this study, tasks arrive randomly, tasks are independent (i.e., no inter-task communication), and tasks have priorities and multiple soft deadlines. The value of a task is calculated based on the priority of the task and the completion time of the task with respect to its deadlines. The goal of a dynamic mapping heuristic in this research is to maximize the value accrued of completed tasks in a given interval of time. This research proposes, evaluates, and compares eight dynamic mapping heuristics. Two static mapping schemes (all arrival information of tasks are known) are designed also for comparison. The performance of the best heuristics is 84% of a calculated upper bound for the scenarios considered

A prospective study on total hip arthroplasty outcome in hip fracture compared with matched elective cohort

Background: We conducted a prospective study to compare the outcomes of THA for hip fractures with a best-matched elective cohort.Method: We prospectively reviewed patients underwent THA for hip fractures from 2017 to 2019. The modified Harris Hip Score (mHHS) and complications were recorded. Our control group was elective THA cases matched for the month of operation, age, gender, implants, side of operation and surgeon’s grade. Unmatched cases were excluded.Results: Forty-one THA for hip fractures and forty-one matched elective THA were compared. The total modified Harris Hip Score [mHHS (total)] was significantly lower preoperatively in elective cohort (trauma vs elective: 60.3 vs 41.4, p<0.001) and achieved significantly higher score than trauma cohort one-year postoperatively (82.6 vs 88.2, p= 0.029). The trauma cohort had similar mHHS (function) pre- and postoperatively, and no significant difference was witnessed between both cohorts postoperatively (35.1 vs 37.6, p= 0.142). The mHHS (pain) was significantly higher in trauma cohort preoperatively (19.8 vs 12.7, p= 0.034), but the elective cohort achieved significantly higher mHHS (pain) than trauma cohort at one-year postoperative (40.1 vs 42.7, p= 0.027). Both cohorts had similar complication rates.Conclusion: This is the first matched prospective study on hip fracture patients that underwent THA, with one year follow up results and the involvement of preoperative and postoperative functional outcomes. With careful patient selection, trauma THA patients can return to their pre-injured function within a year and had comparable function scores with elective THA patients, without increased complication rates

Dynamic mapping in a heterogeneous environment with tasks having priorities and multiple deadlines

In a distributed heterogeneous computing system, the resources have different capabilities and tasks have different requirements. To maximize the performance of the system, it is essential to assign resources to tasks (match) and order the execution of tasks on each resource (schedule) in a manner that exploits the heterogeneity of the resources and tasks. The mapping (defined as matching and scheduling) of tasks onto machines with varied computational capabilities has been shown, in general, to be an NP-complete problem. Therefore, heuristic techniques to find a near-optimal solution to this mapping problem are required. Dynamic mapping is performed when the arrival of tasks is not known a priori. In the heterogeneous environment considered in this study, tasks arrive randomly, tasks are independent (i.e., no communication among tasks), and tasks have priorities and multiple deadlines. Thi