Why Do Patients Choose Skilled Nursing Facilities After Total Hip and Knee Arthroplasty?

BACKGROUND: Current research indicates that total joint arthroplasty patients who are discharged to skilled nursing facilities (SNFs) have higher complication rates as compared to home. Many factors like age, sex, race, Medicare status, and past medical history have been shown to influence discharge destination. The present study sought to gather patient-indicated reasons for SNF discharge and identify potentially modifiable factors influencing the decision. METHODS: Primary total joint arthroplasty patients were asked to complete surveys at their presurgical and 2-week postsurgical follow-up appointments. The surveys included home access and social support questions as well as patient-reported outcome measures: Patient-Reported Outcomes Measurement and Information System, Risk Assessment and Prediction Tool, Knee injury and Osteoarthritis Outcome Score for Joint Replacement, or Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement. RESULTS: Of 765 patients who met inclusion criteria, 3.9% were discharged to an SNF and these were more frequently post-THA, women, older, Black, and persons living alone. Regression analyses indicated that lower Risk Assessment and Prediction Tool score, higher age, no caregiver presence, and Black race were significantly associated with SNF discharge. Patients discharged to an SNF most commonly reported social concerns rather than medical or home access concerns as the main factor for SNF discharge. CONCLUSIONS: While age and sex are nonmodifiable factors, the availability of a caregiver and social support represents an important modifiable factor in regard to discharge destination. Dedicated attention during the preoperative planning period may help augment social support and avoid unnecessary discharges to SNFs.

Analysis of restraint use in pregnant versus non-pregnant populations involved in motor vehicle collisions.

BACKGROUND: Traumatic injuries obtained by pregnant females in motor vehicle collisions present unique treatment challenges for trauma and orthopaedic surgeons. Understanding safety choices in this population can help physicians and public safety advocates in delivering effective and targeted safety messages. METHODS: A publicly available, de-identified national data set that documents crash information (NASS-CDS) was examined to identify cohorts of pregnant and non-pregnant vehicle occupants and regression analysis employed to identify factors associated with belt non-use. RESULTS: Pregnant women were found to have significantly lower rates of belt use compared to non-pregnant females (70.0% vs. 90.3%, Rao-Scott Sample Weighted Chi-Square p = 0.0265). Logistic regression identified younger age and sitting in the back seat as associated with lower rates of belt use. CONCLUSION: Pregnant women wear belts at significantly lower frequencies than non-pregnant women and youth and second row seating increase noncompliance rates. This work suggests the need for targeted intervention strategies to improve belt compliance.

Factors influencing side air curtain deployment in rollover motor vehicle accidents.

Objective: Recent changes in FMVSS have led to the utilization of side air curtains to provide occupant retention during rollover events. However, the safety advantage provided by the air curtains relies on the vehicle system's ability to detect the rollover event and deploy the curtains. The purpose of this study is to identify crash and vehicle characteristics in motor vehicle rollovers that influence side air curtain deployment and occupant outcomes. The current study aims to improve the understanding of rollover events and inspire more robust air curtain deployment strategies.Methods: Study data were extracted from rollover cases documented in the NASS-CDS data set from 2011 to 2015. Vehicle model years of 2011 or later with side air curtains installed were examined. The presence of a rollover sensor in each vehicle was determined from vehicle content data available on the Insurance Institute for Highway Safety's crash rating website. The resulting data set contained 14,003 weighted cases of rollover accidents in which the side air curtain did not deploy (40 raw count) and 23,178 cases of deployment (80 raw count).Results: Several crash event and vehicle characteristics were similar for the nondeployed and deployed groups, including number of quarter turns, primary location of damage, initiating event for the rollover, and vehicle model year. However, the nondeployed group included significantly more passenger vehicle body types (vs. SUV or truck) and had a significantly lower rate of rollover sensor presence. Presence of a rollover sensor increased the odds air curtain deployment by a factor of 36.5 (95% confidence interval [CI], 5.06-265). Cases in which both side air curtains deployed resulted in a higher frequency of injured occupants (Maximum Abbreviated Injury Scale [MAIS] ≥ 3). However, rollover events resulting in these injuries were also associated with higher rates of impact with another object or vehicle and damage to the roof of the vehicle, suggesting a higher energy event.Conclusions: Nondeployment of the side curtain airbags in rollovers occurred more frequently in vehicles without dedicated rollover sensors, which were most frequently passenger vehicles.

Removal torque of nail interlocking screws is related to screw proximity to the fracture and screw breakage.

Studies have shown that titanium implants can be challenging to explant due to the material's excellent biocompatibility and resulting osseointegration. Clinically, titanium alloy nail interlocking screws may require removal to dynamize a construct or revise the nail due to nonunion, infection, pain, or periprosthetic fracture. This study was designed to determine what variables influence the removal torque for titanium alloy interlocking screws. An intramedullary nail with four interlocking screws was used to stabilize a 1-cm segmental femoral defect in a canine model for 16 weeks. The animals were observed to be active following a several-day recovery after surgery. In six animals, the femora and implanted nail/screws were first tested to failure in torsion to simulate periprosthetic fracture of an implant after which the screws were then removed. In four additional animals, the screws were removed without mechanical testing. Both intraoperative insertional and extraction torques were recorded for all screws. Mechanical testing to failure broke 10/24 screws. On average, the intact screws required 70% of the insertional torque during removal while broken screws only required 16% of the insertional torque (p < 0.001). In addition, intact screws closer to the fracture required 2.8 times more removal torque than the outboard distal screw (p < 0.005). On average, the angle of rotation to peak torque was ∼80°. The peak axial load did not significantly correlate with the torque required to remove the screws. On average, the removal torque was lower than at the time of insertion, and less torque was required to remove broken screws and screws remote to the fracture. However, broken screws will require additional time to retrieve the remaining screw fragment. This study suggests that broken screws and screws in prematurely active patients will require less torque to remove.

The influence of occupant anthropometry and seat position on ejection risk in a rollover.

PURPOSE: During rollover crashes, ejection increases an occupant's risk of severe to fatal injury as compared to risks for those retained in the vehicle. The current study examined whether occupant anthropometry might influence ejection risk. Factors such as restraint use/disuse, seating position, vehicle type, and roll direction were also considered in the analysis. METHODS: The current study examined occupant ejections in 10 years of National Automotive Sampling System (NASS) single-event rollovers of passenger vehicles and light trucks. Statistical analysis of unweighted and weighted ejection data was carried out. RESULTS: No statistically significant differences in ejection rates were found based on occupant height, age, or body mass index. Drivers were ejected significantly more frequently than other occupants: 62 percent of unrestrained drivers were ejected vs. 51 percent unrestrained right front occupants. Second row unrestrained occupants were ejected at rates similar to right front-seated occupants. There were no significant differences in ejection rates for near- vs. far-side occupants. CONCLUSIONS: These data suggest that assessment of ejection prevention systems using either a 50th or 5th percentile adult anthropomorphic test dummy (ATD) might provide a reasonable measure of system function for a broad range of occupants. They also support the development of ejection mitigation technologies that extend beyond the first row to protect occupants in rear seat positions. Future studies should consider potential interaction effects (i.e., occupant size and vehicle dimensions) and the influence of occupant size on ejection risk in non-single-event rollovers.

Volume and surface area study of tobramycin-polymethylmethacrylate beads.

Polymethylmethacrylate bone cement beads impregnated with antibiotic are a common treatment for patients with persistent articular joint infections or osteomyelitis. They also are used as a prophylaxis for infection in patients with large soft tissue wounds. The current study was designed to evaluate the relationship between bead geometry and elution of the antibiotic tobramycin by methodically varying the shape of the beads for a given set of volumes. Beads of five shapes (spherical to ovoid) and two volumes were prepared and studied. Only 0.9% to 3.3% of the total amount of tobramycin present actually eluted from the beads in a 96-hour period and of this amount, approximately 1/3 eluted within the first 4 hours. The elution mass data indicate the benefit of numerous, small and elliptically shaped beads for maximal antibiotic availability. Additionally, a mathematical model is presented that describes these findings and can be used to predict tobramycin delivery rates from bone cement beads. This model assumes that the antibiotic is delivered through two mechanisms: fast dissolution of tobramycin initially adhering to the bead surface and slow release by diffusion through the polymer. The results generate diffusion coefficients for tobramycin in polymethylmethacrylate bone cement on the order of 2 x 10 cm/s.

An under-hand steering wheel grasp produces significant injury risk to the upper extremity during airbag deployment.

Recent laboratory investigations suggest that a deploying airbag may fracture the forearm. These studies positioned the arm in an overhand grasp placing the forearm over the airbag module. However, there is little published data on how drivers grip the steering wheel and the general proximity of the upper extremity to the airbag module. The objective of the current study was to identify 'real world' upper extremity positions and to correlate these with accident and experimental data. A survey of the National Automotive Sampling System (NASS) for the years 1995-99 revealed an increase in the number of forearm fractures due to driver-airbag interaction. As NASS does not provide the position of the forearm, common upper extremity positions were identified in a volunteer driving population. These positions were simulated using a specially instrumented 50(th) percentile male dummy to determine the relative injury risk for the different positions. Analysis showed that an under hand grasp of the wheel turned 90 degrees yielded the highest magnitude impact event. This single position was then simulated in 9 cadaver experiments. Dual stage airbag deployments produced forearm fractures in 2 arms. Experiments using the contralateral arms from the fractured subjects with a single stage airbag deployment produced no fractures. Analysis of forearm kinematics suggests that increasing forearm velocity and thus, acceleration exposure, is associated with forearm injury. Further, the data suggests that reductions in acceleration exposure via reduced airbag inflation decreased the apparent risk of forearm fracture.