3D digital image correlation evaluation of arthrodesis implants.

BACKGROUND: Hallux valgus is a pathological condition that is typically treated via the Lapidus procedure. The purpose of this study was to understand the biomechanical characteristics of bone, implant devices and the bone-implant interface. METHODS: In-situ digital image correlation was performed on polyurethane foam, a known bone substitute in a modified three-point bend test frame. We introduced this modified rig as an enhanced methodology for characterizing bone and implant device mechanical performance. This new methodology was validated using aluminum rod specimens, in three and four-point bend setups followed by new configurations to reveal implications of load configurations on joint displacement and implant performance. Bone substitute specimens were constructed with nitinol staples or locking plate to minimize gapping at the 1st tarsometatarsal during testing. FINDINGS: Bone-implant interface characterization was enabled by digital image correlation, identifying maximum strain concentrations of 1.5% along the interfaces. Interfacial characteristics were analyzed in context with gap displacement allowed by the implant over cyclical loading. The locking plate implant and nitinol staples gapped an average of 2.2 mm and 3.2 mm respectively under 50 Newtons. Removing all load, the locking plate implant and nitinol staples averaged ~0.8 mm and ~0.3 mm of residual gapping respectively. INTERPRETATION: Our results demonstrate that locking plates provide more initial stability and resistance against gapping under load but are unable to recover compression throughout repetitive loading as seen with the nitinol staple technology. This could lead to a paradigm shift in materials used for early weight bearing protocols post-operation.

A clinical pathway to minimize computed tomography for suspected nephrolithiasis in children.

INTRODUCTION: Ultrasound (US) imaging is preferred in the initial evaluation for children with suspected nephrolithiasis; however, computed tomography (CT) continues to be used in this setting with resultant unnecessary ionizing radiation exposure. The study institution implemented a standardized clinical pathway to reduce rates of CT utilization for children with nephrolithiasis. OBJECTIVE: The aim of this study was to evaluate the impact of this pathway on initial imaging strategies for children with suspected nephrolithiasis. STUDY DESIGN: A standardized pathway was designed and implemented using a systematic quality improvement process. A suspected cohort was created using 'reason for study' search terms consistent with a nephrolithiasis diagnosis. A confirmed cohort of children with a final diagnosis of nephrolithiasis was derived from this suspected cohort. The primary outcome was CT use as the initial imaging study in children with suspected or confirmed nephrolithiasis presenting to the emergency department (ED) between October 2013 and February 2018. Comparisons were made before and after pathway implementation (October 2015). Secondary outcomes included rates of CT scan within 30 days, while balancing measures included rates of admission, ED length of stay, and return visits. RESULTS: A total of 534 children with suspected (220 prepathway; 314 postpathway) and 90 children with confirmed (37 prepathway; 53 postpathway) nephrolithiasis were included. For the suspected cohort, CT scans performed as the initial imaging evaluation (9.2% vs 2.5%, P = 0.001) and at any time during the index visit (15.7% vs 5.7%, P = 0.001) decreased after pathway implementation. Within the confirmed cohort, a non-significant decrease in initial CT rates was observed after implementation. No differences were observed in admission rates or ED length of stay after implementation. A trend toward lower return visits to the ED was seen after pathway implementation (5.5% vs 2.2%, P = 0.058). DISCUSSION: Within a tertiary care pediatric ED associated with a strong institutional experience with clinical pathways, initial CT rates were decreased after pathway implementation for children with suspected nephrolithiasis. While retrospective assessment of suspected disease is limited, this is one of the first studies to address imaging patterns for nephrolithiasis beyond the final discharge diagnosis, thus capturing a broader cohort of children. Children with suspected nephrolithiasis can be safely managed with an US-first approach, and postvisit CT scans are rarely necessary for management. CONCLUSIONS: A standardized clinical pathway for suspected nephrolithiasis can reduce rates of initial and overall CT utilization without adversely impacting downstream care.

Native American infant mortality in Wisconsin.

An infant mortality rate is an important public health measure because it may indicate unmet health needs or unfavorable environmental factors. The infant mortality rate for Native Americans in Wisconsin has decreased over the past several years, although there remains a discrepancy between Native Americans, all races combined and the Healthy People 2000 goal. The Wisconsin American Indian Infant Mortality Review Project (WAIIMR) conducted a study to understand local underlying factors that contributed to infant deaths and to recommend local health initiatives that could be developed to have a positive impact on the health of infants and mothers. The results from the WAIIMR Project and more recent Wisconsin birth record data are discussed in this paper. Two risk factors, levels of prenatal care and maternal smoking during pregnancy, show discrepancies between races and warrant further investigation. Native American communities in Wisconsin are addressing risk factors affecting maternal and child health through projects such as Honoring Our Children and The Michigan/Wisconsin Epidemiology Center.

Access by general practitioners to physiotherapy department of a district general hospital.

There has been much opposition, voiced most notably in the Tunbridge Report, to general-practitioner access to hospital rehabilitation services. Co-operation between general practitioners, physiotherapists, and the consultant with responsibility for the physiotherapy department at a general district hospital has provided an efficient open-access service. This service has been welcomed by the general practitioners because it supplies prompt treatment for their patients and by the physiotherapists because it enables them to minimise disability by treating musculoskeletal problems at an early stage.