Diagnostic work-up of suspected scaphoid fractures

The diagnostic work-up of patients with (suspected) scaphoid fractures is flawed by “underdiagnosis” and “over-treatment”. We are unable to identify all scaphoid fractures during patients’ initial visit in Emergency Department, if we continue to rely on painful anatomic snuffbox on clinical examination and plain radiographs as the mainstay of diagnostic imaging. To assure that we do not miss – “underdiagnose” – any scaphoid fractures and do not unnecessarily “over”-treat patients, we have to improve our diagnostic protocol from both clinical- as well as imaging perspectives. The overall aim of this PhD Thesis was to assess current management and to improve both clinical and diagnostic strategies, in order to create a new and more efficient protocol that leads to earlier and more accurate diagnosis, reduces overtreatment, follow-up imaging and outpatient clinic visits without an increased risk of missing a fracture

Comparison of CT and MRI for Diagnosis of Suspected Scaphoid Fractures

Background: There is no consensus on the optimum imaging method to use to confirm the diagnosis of true scaphoid fractures among patients with suspected scaphoid fractures. This study tested the null hypothesis that computed tomography (CT) and magnetic resonance imaging (MRI) have the same diagnostic performance characteristics for the diagnosis of scaphoid fractures. Methods: Thirty-four consecutive patients with a suspected scaphoid fracture (tenderness of the scaphoid and normal radiographic findings after a fall on the outstretched hand) underwent CT and MRI within ten days after a wrist injury. The reference standard for a true fracture of the scaphoid was six-week follow-up radiographs in four views. A panel including surgeons and radiologists came to a consensus diagnosis for each type of imaging. The images were considered in a randomly ordered, blinded fashion, independent of the other types of imaging. We calculated sensitivity, specificity, and accuracy as well as positive and negative predictive values. Results: The reference standard revealed six true fractures of the scaphoid (prevalence, 18%). CT demonstrated a fracture in five patients (15%), with one false-positive, two false-negative, and four true-positive results. MRI demonstrated a fracture in,seven patients (21%), with three false-positive, two false-negative, and four true-positive results. The sensitivity, specificity, and accuracy were 67%, 96%, and 91%, respectively, for CT and 67%, 89%, and 85%, respectively, for MRI. According to the McNemar test for paired binary data, these differences were not significant. The positive predictive value with use of the Bayes formula was 0.76 for CT and 0.54 for MRI. The negative predictive value was 0.94 for CT and 0.93 for MRI: Conclusions: CT and MRI had comparable diagnostic characteristics. Both were better at excluding scaphoid fractures than they were at confirming them, and both were subject to false-positive and false-negative interpretations. The best reference standard is debatable, but it is now unclear whether or not bone edema on MRI and small unicortical lines on CT represent a true fracture. Level of Evidence: Diagnostic Level I. See. Instructions to Authors for a complete description of levels of evidenc

Variatie in beleid bij vermoeden op scafoïdfractuur

This study evaluated the daily clinical practice for management of patients with suspected scaphoid fractures in hospitals in the Netherlands and compared it with recommendations from the current literature. Questionnaire-based investigation. Doctors working in emergency departments in hospitals in the Netherlands were asked to complete an 8-question survey including questions on diagnostic strategies, treatment type and the time between different steps in the management policy. Doctors from 90 of the 100 hospitals approached completed the questionnaire. A total of 71 of these 90 hospitals had an established protocol. In the other 19 it depended on the preference of the treating doctor. In 75 hospitals a follow-up outpatient clinic appointment was made for within 10 days. In 70 hospitals X-rays were repeated before additional imaging investigation. CT was the most frequently used additional investigation in 35 hospitals, followed by bone scintigraphy (12) and MRI (2). No additional investigation was carried out in 11 hospitals and when X-rays showed no abnormalities treatment was implemented on the basis of clinical evaluation. In 72 hospitals the wrist was immobilised with a lower-arm plaster cast including the thumb. Lower-arm plaster cast not including the thumb was used in 1 hospital. There is a great deal of variation in diagnosis and treatment of patients with a suspected scaphoid fracture within hospitals in the Netherlands. Furthermore, management policy in most hospitals is not in keeping with the most recent recommendations. Evidence-based guidelines are required in order to limit over-diagnosis and unnecessary immobilisatio

Accuracy of cup placement in total hip arthroplasty by means of a mechanical positioning device: a comprehensive cadaveric 3d analysis of 16 specimens

Introduction: We tested whether a mechanical device (such as Hipsecure) to pinpoint the anterior pelvic plane (APP) as a guide can improve acetabular cup placement. To assess accuracy we asked: (1) is the APP an effective guide to position acetabular cup placement within acceptable ° of divergence from the optimal 40° inclination and 15° anteversion; (2) could a mechanical device increase the number of acetabular cup placements within Lewinnek’s safe zone (i.e. inclination 30° to 50°; anteversion 5° to 25°)? Methods: 16 cadaveric specimens were used to assess the 3D surgical success of using a mechanical device APP to guide acetabular cup placement along the APP. We used the Hipsecure mechanical device to implant acetabular cups at 40° inclination and 15° anteversion. Subequently, all cadaveric specimens with implants were scanned with a CT and 3D models were created of the pelvis and acetabular cups to assess the outcome in terms of Lewinnek’s safe zones. Results: The mean inclination of the 16 implants was 40.6° (95% CI, 37.7–43.4) and the mean anteversion angle was 13.4° (95% CI, 10.7–16.1). All 16 cup placements were within Lewinnek’s safe zone for inclination (between 30° and 50°) and all but 2 were within Lewinnek’s safe zone for anteversion (between 5° and 25°). Conclusion: In cadaveric specimens, the use of a mechanical device and the APP as a guide for acetabular cup placement resulted in good positioning with respect to both of Lewinnek’s safe zones

Diagnostic Performance Tests for Suspected Scaphoid Fractures Differ with Conventional and Latent Class Analysis

Evaluation of the diagnostic performance characteristics of radiographic tests for diagnosing a true fracture among suspected scaphoid fractures is hindered by the lack of a consensus reference standard. Latent class analysis is a statistical method that takes advantage of unobserved, or latent, classes in the data that can be used to determine diagnostic performance characteristics when there is no consensus reference (gold) standard. We therefore compared the diagnostic performance characteristics of MRI, CT, bone scintigraphy, and physical examination to identify true fractures among suspected scaphoid fractures. We used data from two studies, one that prospectively studied 34 patients who had MRI and CT of the wrist, and a second that studied 78 patients who had MRI, bone scintigraphy, and structured physical examination. We compared the diagnostic performance characteristics calculated by latent class analysis with those calculated using formulas based on a reference standard. In the first cohort, the calculated sensitivity and specificity with latent class analysis were different than those with traditional reference standard-based calculations for the CT in the scaphoid planes (sensitivity, 0.78 versus 0.67; specificity, 1.0 versus 0.96) and the MRI (sensitivity, 0.80 versus 0.67; specificity, 0.93 versus 0.89). In the second cohort, the greatest differences were in the sensitivity of MRI (0.84 versus 0.75) and the sensitivities of physical examination maneuvers (range, 0.63-0.73 versus 1.0). The diagnostic performance characteristics calculated using latent class analysis may differ from those calculated according to formulas based on a reference standard. We believe latent class analysis merits further study as an option for assessing diagnostic performance characteristics for orthopaedic conditions when there is no consensus reference standard. Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidenc

Detecting scaphoid fractures in wrist injury: a clinical decision rule

Introduction: The aim of this study was to develop and validate an easy to use clinical decision rule, applicable in the ED that limits the number of unnecessary cast immobilizations and diagnostic follow-up in suspected scaphoid injury, without increasing the risk of missing fractures. Methods: A prospective multicenter study was conducted that consisted of three components: (1) derivation of a clinical prediction model for detecting scaphoid fractures in adult patients following wrist trauma; (2) internal validation of the model; (3) design of a clinical decision rule. The predictors used were: sex, age, swelling of the anatomic snuffbox, tenderness in the anatomic snuffbox, scaphoid tubercle tenderness, painful ulnar deviation and painful axial thumb compression. The outcome measure was the presence of a scaphoid fracture, diagnosed on either initial radiographs or during re-evaluation after 1–2 weeks or on additional imaging (radiographs/MRI/CT). After multivariate logistic regression analysis and bootstrapping, the regression coefficient for each significant predictor was calculated. The effect of the rule was determined by calculating the number of missed scaphoid fractures and reduction of suspected fractures that required a cast. Results: A consecutive series of 893 patients with acute wrist injury was included. Sixty-eight patients (7.6%) were diagnosed with a scaphoid fracture. The final prediction rule incorporated sex, swelling of the anatomic snuffbox, tenderness in the anatomic snuffbox, painful ulnar deviation and painful axial thumb compression. Internal validation of the prediction rule showed a sensitivity of 97% and a specificity of 20%. Using this rule, a 15% reduction in unnecessary immobilization and imaging could be achieved with a 50% decreased risk of missing a fracture compared with current clinical practice. Conclusions: This dataset provided a simple clinical decision rule for scaphoid fractures following acute wrist injury that limits unnecessary immobilization and imaging with a decreased risk of missing a fracture compared to current clinical practice. Clinical prediction rule: 1/(1 + EXP (−(0.649662618 × if man) + (0.51353467826 × if swelling anatomic snuffbox) + (−0.79038263985 × if painful palpation anatomic snuffbox) + (0.57681198857 × if painful ulnar deviation) + (0.66499549728 × if painful thumb compression)−1.685). Trial registration: Trial register NTR 2544, www.trialregister.nl