Machine learning outperforms clinical experts in classification of hip fractures.

Hip fractures are a major cause of morbidity and mortality in the elderly, and incur high health and social care costs. Given projected population ageing, the number of incident hip fractures is predicted to increase globally. As fracture classification strongly determines the chosen surgical treatment, differences in fracture classification influence patient outcomes and treatment costs. We aimed to create a machine learning method for identifying and classifying hip fractures, and to compare its performance to experienced human observers. We used 3659 hip radiographs, classified by at least two expert clinicians. The machine learning method was able to classify hip fractures with 19% greater accuracy than humans, achieving overall accuracy of 92%.

Follow-up of Indigenous-specific health assessments - a socioecological analysis.

OBJECTIVES: To describe patterns of uptake of Indigenous-specific health assessments and associated follow-up items, and examine the barriers and enablers to delivery and billing of follow-up over the first 3 years of implementation of the Indigenous Chronic Disease Package (ICDP). DESIGN, SETTING AND PARTICIPANTS: We used a socioecological approach to analyse data derived from the Sentinel Sites Evaluation of the ICDP - with data from 24 sites across Australia. Administrative data (1 May 2009 to 30 May 2012) and program data (1 March 2010 to 30 May 2012) were provided by the Department of Health. Data on barriers and enablers to follow-up of health assessments were obtained from community focus groups, in-depth interviews and discussions with key informants (1 November 2010 to 30 December 2012). MAIN OUTCOME MEASURES: Monthly number of Medicare Benefits Schedule items claimed for Indigenous-specific health services and follow-up; qualitative data on enablers and barriers categorised according to patient, patient-health service relationship, health service or organisation, community and policy environment levels or influence. RESULTS: There was an increase in the uptake of health assessments, but relatively limited delivery of follow-up care and billing for Indigenous-specific follow-up items. Follow-up was constrained by factors that operated at various levels: patient, interpersonal, health service, community and policy. Constraints included practitioners' lack of awareness of item numbers, staffing, poor state of clinical information systems, billing against non-Indigenous-specific items or more general follow-up items, emphasis on health assessments with less attention to requirements for follow-up, limited capacity to arrange and facilitate follow-up, and communication and transport challenges for patients. CONCLUSIONS: Work is required across various levels of the system to address barriers to follow-up care. Enhancing follow-up care is vital to achieving health benefits from the large financial and human resource investment in health assessments.

A semi-automated measurement technique for the assessment of radiolucency.

The assessment of radiolucency around an implant is qualitative, poorly defined and has low agreement between clinicians. Accurate and repeatable assessment of radiolucency is essential to prevent misdiagnosis, minimize cases of unnecessary revision, and to correctly monitor and treat patients at risk of loosening and implant failure. The purpose of this study was to examine whether a semi-automated imaging algorithm could improve repeatability and enable quantitative assessment of radiolucency. Six surgeons assessed 38 radiographs of knees after unicompartmental knee arthroplasty for radiolucency, and results were compared with assessments made by the semi-automated program. Large variation was found between the surgeon results, with total agreement in only 9.4% of zones and a kappa value of 0.602; whereas the automated program had total agreement in 81.6% of zones and a kappa value of 0.802. The software had a 'fair to excellent' prediction of the presence or the absence of radiolucency, where the area under the curve of the receiver operating characteristic curves was 0.82 on average. The software predicted radiolucency equally well for cemented and cementless implants (p = 0.996). The identification of radiolucency using an automated method is feasible and these results indicate that it could aid the definition and quantification of radiolucency.

Localized cartilage assessment with three-dimensional dGEMRIC in asymptomatic hips with normal morphology and cam deformity.

BACKGROUND: Cam deformities cause femoroacetabular impingement and damage the acetabular labral-chondral complex. The aims of this study were to investigate the potential of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) to detect cartilage disease in asymptomatic hips with cam deformities compared with morphologically normal hips, establish whether dGEMRIC could identify advanced disease in hips with positive clinical findings, and establish whether cartilage damage correlated with the severity of the cam deformity. METHODS: Subjects were recruited from a prospective study of individuals with a family history of osteoarthritis and their spouses who served as control subjects. Their symptoms and impingement test results were recorded. Asymptomatic hips with normal radiographic joint-space width were placed in a subgroup according to the presence of a cam deformity and the impingement test result. dGEMRIC was performed on a 3-T system, studying two regions of interest: the anterosuperior aspect of the acetabular cartilage (T1(acet)) and the total femoral and acetabular cartilage (T1(total)). The ratio T1(acet)/T1(total) gave the relative glycosaminoglycan content in the anterosuperior aspect of the acetabular cartilage. The cohort was placed in subgroups by joint morphology, impingement test status, and genetic predisposition; the mean T1 scores were compared, and the alpha angle and T1 were correlated. RESULTS: Of thirty-two subjects (mean age, fifty-two years), nineteen had cam deformities. Hips with a cam deformity had reduced acetabular glycosaminoglycan content compared with normal hips (mean T1(acet)/T1(total), 0.949 and 1.093, respectively; p = 0.0008). Hips with a positive impingement test result had global depletion of glycosaminoglycan compared with hips with a negative result (mean T1(total), 625 ms versus 710 ms; p = 0.0152). T1(acet) inversely correlated with the magnitude of the alpha angle (r = -0.483, p = 0.0038), suggesting that the severity of cartilage damage correlates with the magnitude of the cam deformity. All of these differences occurred irrespective of genetic predisposition. CONCLUSIONS: The dGEMRIC technique can detect cartilage damage in asymptomatic hips with cam deformities and no radiographic evidence of joint space narrowing. This damage correlates with cam deformity severity. Further study of the application of dGEMRIC as an imaging biomarker of early osteoarthritis is justified to validate its prognostic accuracy, identify subjects for clinical trials, and evaluate the effectiveness of surgical procedures.

Avascular necrosis associated with fracture of the femoral neck after hip resurfacing: histological assessment of femoral bone from retrieval specimens.

The cause of fracture of the femoral neck after hip resurfacing is poorly understood. In order to evaluate the role of avascular necrosis we compared 19 femoral heads retrieved at revision for fracture of the femoral neck and 13 retrieved for other reasons. We developed a new technique of assessing avascular necrosis in the femoral head by determining the percentage of empty osteocyte lacunae present. Femoral heads retrieved as controls at total hip replacement for osteoarthritis and avascular necrosis had 9% (sd 4; n = 13) and 85% (sd 5; n = 10, p < 0.001) empty lacunae, respectively. In the fracture group the percentage of empty lacunae was 71% (sd 22); in the other group it was 21% (sd 13). The differences between the groups were highly significant (p < 0.001). We conclude that fracture after resurfacing of the hip is associated with a significantly greater percentage of empty osteocyte lacunae within the trabecular bone. This indicates established avascular necrosis and suggests that damage to the blood supply at the time of surgery is a potent risk factor for fracture of the femoral neck after hip resurfacing.

Retention of arthroscopic shoulder skills learned with use of a simulator. Demonstration of a learning curve and loss of performance level after a time delay.

BACKGROUND: In orthopaedic surgery, arthroscopy is an irreplaceable diagnostic and interventional tool, and its breadth of use is increasing. The aim of this study was to investigate the surgeon's capacity for retention of an unfamiliar arthroscopic skill. METHODS: Six fellowship-trained lower-limb surgeons were given standardized instruction regarding the performance of an arthroscopic Bankart suture on a laboratory-based simulator. They performed three single Bankart sutures on each of four occasions, one to two weeks apart. Six months later, the same surgeons repeated the study. They received no further instruction or guidance. Their performance was objectively assessed with use of validated motion-analysis equipment to record the total path length of the surgeon's hands, number of hand movements, and time taken to perform the sutures. RESULTS: A learning curve showing significant and objective improvement in performance was demonstrated for all outcome parameters in both experiments (p < 0.005). The learning curve at six months was a repeated learning curve showing no significant difference from the initial learning curve. CONCLUSIONS: This study objectively demonstrated a loss of all of the initial improvement in the performance of an arthroscopic Bankart suture following a six-month interval in which the surgeons did not do the procedure.

Magnetic resonance imaging for in vivo assessment of three-dimensional patellar tracking.

We have developed a non-invasive measurement technique which can ultimately be used to quantify three-dimensional patellar kinematics of human subjects for a range of static positions of loaded flexion and assessed its accuracy. Knee models obtained by segmenting and reconstructing one high-resolution scan of the knee were registered to bone outlines obtained by segmenting fast, low-resolution scans of the knee in static loaded flexion. We compared patellar tracking measurements made using the new method to measurements made using Roentgen stereophotogrammetric analysis in three cadaver knee specimens loaded through a range of flexion in a test rig. The error in patellar spin and tilt measurements was less than 1.02 degrees and the error in lateral patellar shift was 0.88 mm. Sagittal plane scans provided more accurate final measurements of patellar spin and tilt, whereas axial plane scans provided more accurate measurements of lateral translation and patellar flexion. Halving the number of slices did not increase measurement error significantly, which suggests that scan times can be reduced without reducing accuracy significantly. The method is particularly useful for multiple measurements on the same subject because the high-resolution bone-models need only be created once; thus, the potential variability in coordinate axes assignment and model segmentation during subsequent measurements is removed.

Accurate assessment of patellar tracking using fiducial and intensity-based fluoroscopic techniques.

Accuracies of a point-based and an intensity-based fluoroscopic methods of assessing patella tracking were determined by comparing the pattern of patellar motion with respect to orientation (flexion, internal rotation, and lateral tilt) and translation (lateral, proximal, and anterior) with the pattern of patellar motion measured using Roentgen stereophotogrammetric analysis in three cadaver knee specimens. Each pose in the patellar motion could be obtained from single as well as multiple calibrated fluoroscopic images. The errors using the intensity-based method were slightly higher than those of the point-based method, but they appear to be sufficiently low to detect clinically significant differences in patellar kinematics.

Should total hip arthroplasty femoral components be designed to subside? A radiostereometric analysis study of the Charnley Elite and Exeter stems.

The Charnley Elite and the Exeter stems have different design concepts: The former is designed not to subside, whereas the latter is expected to subside. This radiostereometric analysis study compares the early migration of the 2 stems. For both implants, the 1st year migration was about 4 times faster than the 2nd year. The Exeter migration was predominantly distal (1 mm/y in the 1st year). It also showed slight collapse into valgus, and the head migrated slowly posteriorly (0.3 mm/y in the 1st year). In contrast, the Elite had slow distal migration (0.2 mm/y in the 1st year) and rapid posterior head migration (0.8 mm/y in the 1st year). Four Elites and no Exeters had rapid posterior head migration rates (mean 2.8 mm/y in the 1st year and 0.8 mm/y in the 2nd year). The Elite and the Exeter stems have fundamentally different early patterns of migration, which affect their long-term function; 20% of the Elites and none of the Exeters had rapid posterior head migration in the 1st year and the 2nd year and are likely to fail early. Polished, collarless, tapered designs, such as the Exeter, may be more forgiving than conventional stems designed not to subside.

Safety assessment of potential probiotic lactic acid bacterial strains Lactobacillus rhamnosus HN001, Lb. acidophilus HN017, and Bifidobacterium lactis HN019 in BALB/c mice.

The general safety of immune-enhancing lactic acid bacteria (LAB) strains Lactobacillus rhamnosus HN001 (DR20), Lb. acidophilus HN017, and Bifidobacterium lactis HN019 (DR10) was investigated in a feeding trial. Groups of BALB/c mice were orally administered test LAB strains or the commercial reference strain Lb. acidophilus LA-1 at 2.5 x 10(9), 5 x 10(10) or 2.5 x 10(12) colony forming units (CFU)/kg body weight/day for 4 weeks. Throughout this time, their feed intake, water intake, and live body weight were monitored. At the end of the 4 week observation period, samples of blood, liver, spleen, kidney, mesenteric lymph nodes, and gut tissues (ileum, caecum, and colon) were collected to determine: haematological parameters (red blood cell and platelet counts, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration); differential leukocyte counts; blood biochemistry (plasma total protein, albumin, cholesterol, and glucose); mucosal histology (epithelial cell height, mucosal thickness, and villus height); and bacterial translocation to extra-gut tissues (blood, liver, spleen, kidney and mesenteric lymph nodes). DNA finger printing techniques were used to identify any viable bacterial strains recovered from these tissues. The results demonstrated that 4 weeks consumption of these LAB strains had no adverse effects on animals' general health status, haematology, blood biochemistry, gut mucosal histology parameters, or the incidence of bacterial translocation. A few viable LAB cells were recovered from the tissues of animals in both control and test groups, but DNA fingerprinting did not identify any of these as the inoculated strains. The results obtained in this study suggest that the potentially probiotic LAB strains HN001, HN017, and HN019 are non-toxic for mice and are therefore likely to be safe for human use.

United States health care delivery system, reform, and transition to managed care.

The US health care delivery system, faced with an exponential increase in expenditures during the second part of the 20th century, was forced to explore ways to reduce costs and, at the same time, maintain a high quality of care. Managed care emerged as one of the answers and quickly became one of the predominant health care delivery models. While the cost of health care did go down, it remains unclear what the future holds. Currently, managed care is growing rapidly in publicly funded programs and the changes which are currently underway may be defining those programs in the time to come.

Patients' and physicians' assessment of risks associated with hypertension and benefits from treatment.

BACKGROUND: Perceptions of effects of a medical regimen may affect patients' adherence to therapy. OBJECTIVE: To assess concordance between patients' and physicians' estimations of the risks of hypertension and benefits of treatment during a regular follow-up appointment. DESIGN: A population-based Swedish multicentre study. Patients were included consecutively from a randomized selection of centres (55 primary health care centres and 11 clinics of internal medicine). METHODS: A questionnaire was given to 1013 patients undergoing their individually prescribed antihypertensive therapy and 212 physicians who were caring for these patients. RESULTS: Without therapy, patients perceived the risks of cardiovascular complications to be higher than did their physicians. Patients were not aware that an increasing number of risk factors has an impact on the risk of complications. Patients furthermore rated the benefits of treatment higher than did their physicians (P<0.001). Of the patients, 14% had blood pressures < or = 140/90 mmHg. Most of the patients (61%) were not aware of their target blood pressure. However, when the target pressure was communicated to patients by the physician, patients remembered it accurately. The patients were generally not willing to trade even minor side effects from antihypertensive therapy for benefits of treatment. CONCLUSIONS: There was a high degree of inconsistency between patients' and physicians' estimations of risks of hypertension. Patients estimated the effects of treatment to be more beneficial than did their physicians.

Strategic implications of developing integrated levels of care.

Current reimbursement mechanisms provide incentives for health systems to develop or have access to and utilize a variety of postacute care settings, but not necessarily to provide integrated care across those settings. While most health care systems speak of providing integrated care, few actually do. Several market forces are now making health systems reexamine how care is provided across the continuum and creating the incentives for health systems to integrate care across each level within the continuum. This article describes how to develop integrated levels of care and the strategic implications of doing so.