How to avoid baseplate failure: the effect of compression and reverse shoulder arthroplasty baseplate design on implant stability.

BACKGROUND: Failure to achieve fixation of the glenoid baseplate will lead to clinical failure. The fixation of the baseplate to the scapula must be able to withstand sufficient shear forces to allow bony ingrowth. The importance of compression to neutralize the forces at the baseplate-bone interface has been assumed to be critical in limiting excessive micromotion. The purpose of this study is to determine the effect of compression on implant stability with different baseplate designs. METHODS: Various baseplate designs (1-piece monolithic central screw [1P], 2-piece locking central screw [2PL], and 2-piece nonlocking center screw [2PNL]) were investigated at 3 different compressive forces (high [810 N], medium [640 N], and low [530 N]). Synthetic bone cylinders were instrumented, and peripheral screws were used in all models. The combination of 1 locking and 3 nonlocking peripheral screw fixation was selected as worst-case scenario. Dynamic testing protocol followed the ASTM F2028-17 standard. The baseplate micromotion at high compression was compared to low compression. Additionally, the baseplate micromotion for each design was compared at baseline (first 50 cycles) and at 10,000 cycles for the 3 different compressive forces where motion above 150 µm was defined as failure. RESULTS: Baseplate micromotion was found to negatively correlate with compression (rpb = -0.83, P < .0001). At baseline, all baseplate designs were considered stable, regardless of compression. With high compression, average micromotion at the glenoid baseplate-bone interface remained below the 150-µm threshold for all baseplate designs at 10,000 cycles (1P: 50 ± 10 µm; 2PL: 78 ± 32 µm; 2PNL: 79 ± 8 µm; P = .060). With medium compression, average micromotion at 10,000 cycles for all 3 designs remained below the 150-µm threshold (1P: 88 ± 22 µm; 2PL: 132 ± 26 µm; 2PNL: 107 ± 39 µm). The 2PL design had the highest amount of micromotion (P = .013). With low compression, both 2-piece designs had an average micromotion above the 150-µm threshold whereas the 1-piece design did not (1P: 133 ± 35 µm; 2PL: 183 ± 21 µm; 2PNL: 166 ± 39 µm). The 2PL design had significantly higher micromotion when compared to 1P design (P = .041). DISCUSSION: The stability of a central screw baseplate correlates with the amount of compression obtained and is affected by implant design. For the same amount of compression, more micromotion is observed in a 2-piece design than a 1-piece design.

Increasing Stormwater Capture and Recharge Using Forecast Informed Reservoir Operations, Prado Dam.

The United States Army Corps of Engineers (USACE) operates Prado Dam in southern California for flood risk management and to capture stormwater for groundwater recharge. USACE and the Orange County Water District (OCWD) have collaborated for over 30 years to temporarily store Santa Ana River (SAR) stormflow at Prado Dam for groundwater recharge in the Orange County Groundwater Basin (Basin). USACE, OCWD, and other stakeholders are assessing Forecast Informed Reservoir Operations (FIRO) at Prado Dam as a new operational approach to capture additional supplies of SAR water for groundwater recharge without affecting Prado Dam's primary flood risk management purpose. Many dams, including Prado Dam, do not directly incorporate precipitation and streamflow forecasting in their operations. FIRO is an innovative research and operations partnership that uses weather forecasting, streamflow modeling, and watershed monitoring to help water managers selectively retain or release water from reservoirs in a manner that reflects current and forecasted conditions. A recently completed study, called a Preliminary Viability Assessment of FIRO at Prado Dam, determined that increased stormwater capture, beyond the current program, is viable subject to completion of additional studies. The ultimate increase in stormwater capture is anticipated to largely be a function of community and environmental tolerance for more frequent inundation rather than operational constraints of the dam. FIRO is a promising approach to operating Prado Dam that can increase SAR stormwater capture for recharge to the Basin, reducing the need for imported water and contributing to sustainable groundwater management.

Pre-hospital heparin use for ST-elevation myocardial infarction is safe and improves angiographic outcomes.

AIMS: This study aims to evaluate if pre-hospital heparin administration by paramedics is safe and improves clinical outcomes. METHODS AND RESULTS: Using the multicentre Victorian Cardiac Outcomes Registry, linked with state-wide ambulance records, we identified consecutive patients undergoing primary percutaneous coronary intervention for STEMI between January 2014 and December 2018. Information on thrombolysis in myocardial infarction (TIMI) flow at angiography was available in a subset of cases. Patients receiving pre-hospital heparin were compared to those who did not receive heparin. Findings at coronary angiography and 30-day clinical outcomes were compared between groups. Propensity-score matching was performed for risk adjustment. We identified a total of 4720 patients. Of these, 1967 patients had TIMI flow data available. Propensity-score matching in the entire cohort yielded 1373 matched pairs. In the matched cohort, there was no observed difference in 30-day mortality (no-heparin 3.5% vs. heparin 3.0%, P = 0.25), MACCE (no-heparin 7% vs. heparin 6.2%, P = 0.44), and major bleeding (no-heparin 1.9% vs. heparin 1.4%, P = 0.64) between groups. Propensity-score analysis amongst those with TIMI data produced 552 matched pairs. The proportion of cases with TIMI 0 or 1 flow in the infarct-related artery (IRA) was lower among those receiving pre-hospital heparin (66% vs. 76%, P < 0.001) compared to those who did not. CONCLUSION: In this multicentre, propensity-score matched study, the use of pre-hospital heparin by paramedics was safe and is associated with fewer occluded IRAs in patients presenting with STEMI.

Trends in Australian inguinal hernia repair rates: a 15-year population study.

BACKGROUND: An inguinal hernia is one of the most common surgical pathologies, and therefore the repair of an inguinal hernia is one of the most common general surgical procedures. The aim of this study was to assess the trend in inguinal hernia repair (IHR) rates in Australia between 2000/2001 and 2014/2015 using population data from public and private hospitals. METHODS: ICD-10 data cubes from the Australian Institute of Health and Welfare were analysed to determine the number of inguinal hernia repairs performed, open or laparoscopically, between 2000/2001 and 2014/2015 financial years. These data were combined with the Australian Bureau of Statistics population data estimates for the corresponding years, to give a procedure per 100 000 estimates. RESULTS: Incidence of IHRs within Australia decreased from 217 to 194 per 100 000 population over the 15-year study period. There was a clear shift towards increased uptake of laparoscopic surgery with a subsequent fall in rates of open IHRs. Males accounted for the majority of IHR procedures. Unilateral repair was more common; however, the incidence of unilateral repair rates decreased while bilateral IHR rates increased over the study period. CONCLUSION: Laparoscopic techniques are increasingly being used within public and private institutions across the country for inguinal hernia repair. There has also been a decrease in the incidence of IHR procedures performed per year over the 15-year period studied, consistent with published literature from Europe and the USA.

Distributed Temperature Sensing to Measure Infiltration Rates Across a Groundwater Recharge Basin.

Managed aquifer recharge is used to augment groundwater resources and provide resiliency to water supplies threatened by prolonged droughts. It is important that recharge facilities operate at their maximum efficiency to increase the volume of water stored for future use. In this study, we evaluate the use of distributed temperature sensing (DTS) technology as a tool to measure high-resolution infiltration rates at a large-scale recharge facility. Fiber optic cable was laid out inside a spreading basin in a spiral pattern, at two different depths. The cables measured the propagation of diurnal surface water temperature oscillations into the basin depth. The rate of heat propagation is proportional to the velocity of the water, making it possible to estimate the infiltration rate from the temperature measurements. Our results showed that the infiltration rate calculated from DTS, averaged over the entire basin, was within 5% of the infiltration rate calculated using a conventional metering method. The high-resolution data obtained from DTS, both spatially and temporally, revealed heterogeneous infiltration rates throughout the basin; furthermore, tracking the evolution of infiltration rates over time revealed regions with consistently high infiltration rates, regions with consistently low infiltration rates, and regions that evolved from high to low rates, which suggested clogging within that region. Water utilities can take advantage of the high-resolution information obtained from DTS to better manage recharge basins and make decisions about cleaning schedule, frequency, and extent, leading to improved basin management strategies, reduced O&M costs, and increased groundwater recharge.

Inpatient rehabilitation did not positively affect 6-month patient-reported outcomes after hip or knee arthroplasty.

BACKGROUND: The aim of this study was to compare patient-reported outcomes 6 months after hip or knee arthroplasty in subjects who were discharged to home compared to those who attended inpatient rehabilitation. METHODS: Seven hundred and forty-eight consecutive total hip or knee replacement patients were identified from a prospective database. Preoperative and 6-month post-operative patient-reported outcome measures were recorded. Forty-four patients discharged directly to home were cohort matched by age, gender, procedure and surgeon to 44 patients from the cohort who received inpatient care. Patient outcomes were compared using SPSS version 24 software. RESULTS: Both cohorts saw significant improvements from baseline at 6 months. Median length of rehabilitation for the inpatient group was 7 days (4-16 days). There was no significant difference between the groups based on patient-reported outcomes. There was a clinically significant difference (P = 0.047) in the body mass index of the Home Group (mean = 27) to Rehab Group (mean = 29). CONCLUSION: Our study has shown that inpatient rehabilitation after hip or knee arthroplasty did not positively affect 6-month patient-reported satisfaction, expectation, pain, quality of life, activities of daily living scores, when compared with subjects who were discharged direct to home. A significant average saving of $5600 per patient with the use of home discharge is a promising avenue for health cost reduction, and health resource distribution.

Measuring artificial recharge with fiber optic distributed temperature sensing.

Heat was used as a tracer to measure infiltration rates from a recharge basin. The propagation of diurnal oscillation of surface water temperature into the basin bed was monitored along a transect using Fiber Optic Distributed Temperature Sensing (FODTS). The propagation rate was related to downward specific discharge using standard theory of heat advection and dispersion in saturated porous media. An estimate of the temporal variation of heat propagation was achieved using a wavelet transform to find the phase lag between the surface temperature diurnal oscillation and the correlated oscillation at 0.33 and 0.98 m below the bed surface. The wavelet results compared well to a constant velocity model of thermal advection and dispersion during periods of relatively constant discharge rates. The apparent dispersion of heat was found to be due primarily to hydrodynamic mechanisms rather than thermal diffusion. Specific discharge estimates using the FODTS technique also compared well to water balance estimates over a four month period, although there were occasional deviations that have yet to be adequately explained. The FODTS technique is superior to water balance in that it produces estimates of infiltration rate every meter along the cable transect, every half hour. These high resolution measurements highlighted areas of low infiltration and demonstrated the degradation of basin efficiency due to source waters of high suspended solids. FODTS monitoring promises to be a useful tool for diagnosing basin performance in an era of increasing groundwater demand.