Corona mortis and pelvic dissection: Understanding the relationship between anatomical structures and bone areas.

Pelvic fractures are becoming increasingly frequent. The gold standard for surgical managements remains open procedures. Despite its excellent biomechanically results, it can lead to many complications. Minimally invasive surgery could reduce these complications. For complex pelvic trauma, extraperitoneal endoscopic technique has never been described. The aim of this study is to determine anatomical landmarks which are useful for endoscopic pelvic ring surgery using an extraperitoneal approach. The second objective is to compare this minimally invasive procedure to expose the bone versus a traditional open approach. After preparing the vessels with latex injections, 10 specimens are dissected alternately, using an endoscopic method (MIS) on one side and an open method on the other side. Both procedures are performed on the same subject. The visualized bone areas are drilled with burr holes. The marked surfaces are measured with photogrammetry. Finally, the data are processed (surface analysis). An extraperitoneal endoscopic dissection that follows anatomical landmarks can be performed. Bone area (mm2 ) visualized by endoscopy was 74 ± 14 (59-94) compared to 71 ± 16 (48-94) by open method. Paired t-test was performed with no significant difference between the two methods. Skin and muscular incisions were significantly lower in the MIS group (5.1, IC95% [4.1; 6.1], p < 0.001). An extraperitoneal endoscopic dissection of the pelvis can be performed. We also find no significant difference between our method and an open traditional approach concerning bone exposure. We offer a holistic approach to treat pelvic fractures by identifying key anatomical structures.

Commercially-available AI algorithm improves radiologists' sensitivity for wrist and hand fracture detection on X-ray, compared to a CT-based ground truth.

OBJECTIVES: Algorithms for fracture detection are spreading in clinical practice, but the use of X-ray-only ground truth can induce bias in their evaluation. This study assessed radiologists' performances to detect wrist and hand fractures on radiographs, using a commercially-available algorithm, compared to a computerized tomography (CT) ground truth. METHODS: Post-traumatic hand and wrist CT and concomitant X-ray examinations were retrospectively gathered. Radiographs were labeled based on CT findings. The dataset was composed of 296 consecutive cases: 118 normal (39.9%), 178 pathological (60.1%) with a total of 267 fractures visible in CT. Twenty-three radiologists with various levels of experience reviewed all radiographs without AI, then using it, blinded towards CT results. RESULTS: Using AI improved radiologists' sensitivity (Se, 0.658 to 0.703, p < 0.0001) and negative predictive value (NPV, 0.585 to 0.618, p < 0.0001), without affecting their specificity (Sp, 0.885 vs 0.891, p = 0.91) or positive predictive value (PPV, 0.887 vs 0.899, p = 0.08). On the radiographic dataset, based on the CT ground truth, stand-alone AI performances were 0.771 (Se), 0.898 (Sp), 0.684 (NPV), 0.915 (PPV), and 0.764 (AUROC) which were lower than previously reported, suggesting a potential underestimation of the number of missed fractures in the AI literature. CONCLUSIONS: AI enabled radiologists to improve their sensitivity and negative predictive value for wrist and hand fracture detection on radiographs, without affecting their specificity or positive predictive value, compared to a CT-based ground truth. Using CT as gold standard for X-ray labels is innovative, leading to algorithm performance poorer than reported elsewhere, but probably closer to clinical reality. CLINICAL RELEVANCE STATEMENT: Using an AI algorithm significantly improved radiologists' sensitivity and negative predictive value in detecting wrist and hand fractures on radiographs, with ground truth labels based on CT findings. KEY POINTS: • Using CT as a ground truth for labeling X-rays is new in AI literature, and led to algorithm performance significantly poorer than reported elsewhere (AUROC: 0.764), but probably closer to clinical reality. • AI enabled radiologists to significantly improve their sensitivity (+ 4.5%) and negative predictive value (+ 3.3%) for the detection of wrist and hand fractures on X-rays. • There was no significant change in terms of specificity or positive predictive value.

Metaphyseal and Diaphyseal Contours: Variants and Pitfalls.

We discuss several variants of the metaphyseal and diaphyseal bone surfaces that may be misleading in clinical practice. They include metaphyseal stripes, spiculated metaphyseal cortex, cortical desmoid, laminated lateral supracondylar ridge, cortical vascular canals, variations in shape or lucency of normal tuberosities, cortical thickening of normal ridges, and well-organized undulated hyperostosis at the proximal phalanges.

Anatomical Variants of the Sacroiliac Joint.

Anatomical variants are frequently encountered when assessing the sacroiliac joints (SIJ) using magnetic resonance imaging. When not located in the weight-bearing part of the SIJ, variants associated with structural and edematous changes can be misinterpreted as sacroiliitis. Their correct identification is necessary to avoid radiologic pitfalls. This article reviews five SIJ variants involved in the dorsal ligamentous space (accessory SIJ, iliosacral complex, semicircular defect, bipartite iliac bony plate, and crescent iliac bony plate) and three SIJ variants involved in the cartilaginous part of the SIJ (posterior dysmorphic SIJ, isolated synostosis, and unfused ossification centers).

Crystal Diseases of the Spine.

Gout, calcium pyrophosphate deposition disease, and apatite calcifications, the three main crystal disorders, may involve the spine. These disorders can be completely asymptomatic or associated with various clinical symptoms, such as acute flares and more chronic manifestations. This article presents the typical and more unusual imaging features encountered in these disorders.

Minimally invasive removal of deep contraceptive implants under continuous ultrasound guidance is effective, quick, and safe.

OBJECTIVES: The aim of this study was to assess the feasibility, performance, and complications of a non-surgical, minimally-invasive procedure of deep contraceptive implant removal under continuous ultrasound guidance. METHODS: The ultrasound-guided procedure consisted of local anesthesia using lidocaine chlorhydrate 1% (10 mg/mL) with a 21-G needle, followed by hydrodissection using NaCl 0.9% (9 mg/mL) and implant extraction using a Hartmann grasping microforceps. The parameters studied were the implant localization, success and complication rates, pain throughout the intervention, volumes of lidocaïne and NaCl used, duration of the procedure, and size of the incision. Between November 2019 and January 2021, 45 patients were referred to the musculoskeletal radiology department for ultrasound-guided removal of a deep contraceptive implant and were all retrospectively included. RESULTS: All implants were successfully removed en bloc (100%). The mean incision size was 2.7 ± 0.5 mm. The mean duration of the extraction procedure was 7.7 ± 6.3 min. There were no major complications (infection, nerve, or vessel damage). As a minor complication, 21 patients (46.7%) reported a benign superficial skin ecchymosis at the puncture site, spontaneously regressing in less than 1 week. The procedure was very well-tolerated, with low pain rating throughout (1.0 ± 1.5/10 during implant extraction). CONCLUSIONS: Minimally invasive removal of deep contraceptive implants under continuous ultrasound guidance alone is feasible, effective, and safe. In the present cohort, all implants were successfully removed, whatever the location, with short procedural time, small incision size, low pain levels, and no significant complications. This procedure could become a gold standard in this indication. KEY POINTS: • Minimally invasive removal of deep contraceptive implants under continuous ultrasound guidance alone is feasible, which led to a success rate of 100% whatever the location (even close to neurovascular structures), with only a small skin incision (2.7 ± 0.5 mm). • The procedure was safe, quick, without any major complications, and very well tolerated in terms of pain. • This minimally invasive ultrasound-guided procedure could become the future gold standard for the removal of deep contraceptive implants, as an alternative to surgical extraction, even for implants in difficult locations such as subfascial ones or those close to neurovascular structures.

Presurgical Perspective and Postsurgical Evaluation of Non-Achilles Tendons of the Ankle and Retinaculum.

The vast majority of non-Achilles ankle tendinopathies are related to overuse. This article discusses the clinical aspect, imaging appearance, and management of tendinopathies of the lateral, medial, and the anterior compartments with a focus on presurgical perspective and postsurgical evaluation.

MRI signal and morphological alterations of the suprapatellar fat pad in asymptomatic subjects: are these normal variants?

OBJECTIVE: To study the prevalence of suprapatellar fat pad (SPFP) MR alterations in asymptomatic subjects, in relation to a wide range of clinical/imaging parameters, including muscle performance tests and physical activity data. MATERIALS AND METHODS: We prospectively included 110 asymptomatic subjects as part of a cohort study. Inclusion criteria were no knee pain in the last year. Exclusion criteria were any medical/surgical history of a knee disorder. Subjects underwent knee and low-dose posture radiographs [EOS®], 3 T MRI, clinical examination including muscle performance tests, and physical activity monitoring. The presence/absence of SPFP alterations (hyperintensity and mass effect) were assessed through consensus reading on fluid-sensitive sequences. Differences between groups of knees with SPFP alterations and controls were tested for a total of 55 categorical/continuous clinical/imaging parameters, including SPFP relative-T2-signal, trochlear/patellar/lower-limb morphologic measurements. Wilcoxon-rank-sum and chi-square tests were used to compare groups of patients. The histological correlation was obtained in a cadaveric specimen. RESULTS: SPFP alterations were common in asymptomatic subjects: hyperintensity 57% (63/110) and mass effect 37% (41/110), with 27% (30/110) showing both. Among the 55 imaging, clinical, or activity parameters tested, only increased patellar tilt angle (p = 0.02) and TT-TG distance (p = 0.03) were statistically different between groups of SPFP alterations and controls. The histological correlation showed more abundant connective tissue in SPFP compared to the prefemoral fat pad. CONCLUSIONS: SPFP hyperintensity and mass effect are common MRI findings in asymptomatic knees, and they are not related to most imaging, clinical, and activity parameters. Care should be taken not to overcall them pathological findings as they most likely represent normal variants.

3D printing for orbital volume anatomical measurement.

PURPOSE: The aim was to develop a method for reproducible orbital volume (OV) measurement in vivo based on 3D printing. METHODS: Twelve orbits were obtained from dry skulls of the Human Anatomy Department of Lille University. Computer tomography (CT) slice images of these orbits were transformed into stereo-lithography (STL) format and 3D-printed. Bone openings were closed using either putty and cellophane after printing (3D-Orb-1) or at the printing stage in silico using MeshMixer (3D-Orb-2). The results were compared with those of the conventional water-filling method as a control group (Anat-Orb). RESULTS: The observers reported a mean orbital volume of 21.3 ± 2.1 cm3 for the open-skull method, 21.2 ± 2.4 cm3 for the non-sealed 3D-printing method, and 22.2 ± 2.0 cm3 for the closed-print method. Furthermore, the intraclass correlation coefficients (ICCs) showed excellent intra-rater agreement, i.e., an ICC of 0.994 for the first observer and 0.998 for the second, and excellent interobserver agreement (ICC: 0.969). The control and 3D-Orb-1 groups show excellent agreement (ICC: 0.972). The 3D-Orb-2 exhibits moderate agreement (ICC: 0.855) with the control and appears to overestimate orbital volume slightly. CONCLUSION: Our 3D-printing method provides a standardized and reproducible method for the measurement of orbital volume.

Carpal tunnel ultrasound: is the "safe zone" on the ulnar side of the median nerve really avascular?

INTRODUCTION: Numerous publications have studied the regional anatomy of the carpal tunnel to define a "safe zone" to reduce the risk of perioperative neurovascular complications. This zone, located between the ulnar neurovascular bundle and the median nerve, is considered to be safe mainly because of the absence of vascular structures. This study aims to assess the presence of arterioles within this area using superb microvascular imaging (SMI). MATERIALS AND METHODS: The images from patients who underwent a bilateral routine wrist ultrasound with SMI, between January 28 and February 28, 2019, were retrospectively reviewed by two radiologists to evaluate the presence and location of arterioles in the safe zone. In addition, cadaveric wrists injected with intra-arterial red latex underwent dissection of the carpal tunnel. RESULTS: The images from 27 patients (54 wrists) were reviewed. In the safe zone, arterioles were seen superficial to the retinaculum in 36 wrists (36/54; 66.7%) and deep to the retinaculum in 21 wrists (21/54; 38.9%). The arterioles located deep to the retinaculum were more frequently found close to the median nerve (21/54; 38.9%) than to the ulnar artery (9/54; 16.7%). In five cadaveric wrists, arterioles were detected superficial to the retinaculum in 3 wrists (3/5; 60%) and deep to the retinaculum in 2 wrists (2/5; 40%). CONCLUSION: Arterioles can be seen in the safe zone both superficial and deep to the flexor retinaculum. Deep to the retinaculum, they are mainly observed in the proximal aspect of the carpal tunnel and more frequently close to the median nerve. KEY POINTS: • Superb microvascular imaging (SMI) enables the visualization of arterioles within the "safe zone" of the carpal tunnel (visible both superficial and deep to the flexor retinaculum). • Arterioles were more frequently observed in the proximal aspect of the carpal tunnel. • Deep to the retinaculum, arterioles were more frequently seen in proximity to the median nerve.

Styloidogenic compression of the internal jugular vein, a new venous entrapment syndrome?

Internal jugular vein (IJV) thrombosis is mainly related to central venous catheter, malignancy, and ovarian hyperstimulation syndrome. We report a case of IJV thrombosis possibly related to IJV compression between the styloid process and the first cervical vertebra (C1) transverse process. To support this hypothesis, we perform radiological assessment of the IJV and examine its relationship with the styloid process and C1 transverse process in 34 controls. Our results showed a strong correlation between IJV diameter and styloid process-C1 transverse process distance. Compared to control subjects, our patient had a short styloid process-C1 transverse process distance, which suggests its involvement in IJV thrombosis.

Is bone analysis with µCT useful for short postmortem interval estimation?

The evaluation of the postmortem interval (PMI) is an important consideration in forensic medicine. The time between death and the discovery thereof is extremely important, not only in terms of the legal process, but also for the course of the investigation. At the time of the discovery of human bones, the evaluation of the PMI is extremely difficult. To date, there is no really effective tool for this evaluation. The objective of our study is to characterize the architectural modifications of human bones using micro-tomography (µCT) in the postmortem period. Ten bone samples were extracted from a single fresh human cranial vault (no freezing, no embalming) from a body donation. The samples were conserved in a controlled environment (a laboratory hood at 20 °C with 60% humidity) for 10 weeks. Every 2 weeks after the death and the sample extraction from the vault, the samples were analyzed with µCT (resolution 10 µm, Bruker HR1172 ®). The 3D analysis focused on general 3D data related to the trabeculae: the total volume (TV), the bone volume (BV), and the bone surface (BS), as well as specific trabeculae data; namely: the number of trabeculae (TbN), trabecular thickness (TbTh), the average distance between the trabeculae (TbSp), and the trabecular pattern factor (TbPf). Each sample was observed separately and compared to itself over time; no comparisons among samples were made. We used a linear mixed model for repeated measures (an unstructured covariance pattern model) and post hoc comparisons between each consecutive time using linear contrast with an SAS software package, release 9.3 (SAS Institute, Cary, NC). We showed a statistical difference for BS/BV (p = 0.046) over time, with a significant decrease during the first 2 weeks (p = 0.003; mean decrease, - 0.99, 95% CI [- 1.61; - 0.36]), while TbSp (p < 0.0001) showed a significant increase during the first 2 weeks (p < 0.0001; mean increase, 0.022, 95% CI, [- 0.016; - 0.028]).Our study highlighted architectural trabecular modifications on postmortem bones using the µCT. These modifications occurred at an early stage, during the first 2 weeks of conservation. Complementary work will need to be performed to allow for better understanding of the biological phenomena observed and to create databases of osseous taphonomy, starting with various individuals, mediums of conservation, types of bone, and with varying techniques for analysis.

Trapezius perforator flaps: anatomical basis using 58 dissections.

INTRODUCTION: The trapezius muscle is a good option for soft tissue defects in the cervical and thoracic regions. However, pedicled flaps raised from perforators in the trapezius are rare. Through a series of cadaver dissections, the authors aim to map the perforating arteries in the trapezius muscle. MATERIALS AND METHODS: Dissection of 58 anatomical regions in 32 cadavers was carried out. The perforating arteries of the trapezius were inventoried based on their location, dimensions and frequency using the scapular spine and spinous process line as landmarks. RESULTS: In 78% of cases, the main perforators of the trapezius were located along two vertical lines parallel to the spinous process line, 5-6 cm on either side of it, between the scapular spine laterally, the tip of the scapula caudally and the superior margin of the trapezius cranially. On each side of the spinous process line, we found an average of 16 perforators (range 5-27) with an average diameter of 0.6 mm (range 0.1-2.6 mm). CONCLUSION: Our study shows that surgeons can use fixed landmarks when developing trapezius perforator flaps.

Technical note: early post-mortem changes of human bone in taphonomy with µCT.

Post-mortem interval (PMI) estimation is an important issue in forensic medicine, particularly for criminal purposes and legal limitation periods. The goal of the present study is to examine the evolution of the trabecular cranial vault bone after 4 weeks of conservation in a controlled environment with micro-tomography (µCT) analyses.Four bone samples were extracted from a fresh human cranial vault (a donation to science according to the French law) and conserved in an air-controlled environment. The samples were weighed and µCT scanned at a 10-µm resolution every week after death for a month. The µCT features were identical for every sample. Each set of data from the µCTs was reconstructed, registered, and analyzed in terms of the total volume, bone volume, bone surface, number of trabeculae, trabeculae thickness, and mean distance of the trabeculae. The samples were conserved in a glass box in 20 °C air with 60% humidity in a laboratory hood between each µCT acquisition. Descriptive statistics were determined. Each sample was observed and compared to itself over time.After 1 month of conservation, the mean bone volume (-1.9%), bone surface (-5.1%), and trabecular number (-12.35%) decreased, whereas the mean trabecular separation (+5.55%) and trabecular thickness (+12.7%) increased. Many variations (i.e., increases and decreases) were observed between the extraction of the sample and the end of the 4 weeks of conservation. The present observations may be explained by bone diagenesis. Previous observations have indicated that protein and lipid losses occur with bone weight and volume losses. These diagenesis effects may explain the trabecular modifications observed in the present work. We observed many bone variations with the µCT scans between the beginning and the end of the conservation that had no explanations. Additional studies, particularly studies involving statistics, need to be performed to confirm our observations and explain these results more clearly.

Imaging of Sports-related Hand and Wrist Injuries: Sports Imaging Series.

Hand and wrist injuries are common occurrences in amateur and professional sports and many of them are sport-specific. These can be divided into two categories: traumatic injuries and overuse injuries. The aim of this article is to review the most common hand and wrist sports-related lesions. Acute wrist injuries are predominantly bone fractures, such as those of the scaphoid, hamate hook, and ulnar styloid. Ligament lesions are more challenging for radiologists and may lead to carpal instability if undiagnosed. Overuse wrist injuries are mainly represented by tendinous disorders, with De Quervain syndrome and extensor carpi ulnaris tendon disorders being the most common among them; however, there are other possible disorders such as impaction syndromes, stress fractures, and neurovascular lesions. Finally, finger lesions, including closed-tendon injuries (mallet and boutonniere injuries, jersey finger, and boxer's knuckle), flexor pulley injuries, and skier's thumb, should also be detected. (©) RSNA, 2016 Online supplemental material is available for this article.

Traumatic avulsion of the superior extensor retinaculum of the ankle as a cause of subperiosteal haematoma of the distal fibula in children. A retrospective study of 7 cases.

OBJECTIVE: To describe a new sonographic feature for a traumatic lesion of the ankle in children. MATERIALS AND METHODS: We present a retrospective review of superior extensor retinaculum (SER) avulsions diagnosed by ultrasound (US) as a cause of subperiosteal haematoma (SPH) and periosteal apposition of the distal fibula in seven children (3 girls and 4 boys, mean age 13.4 years; age range 10-15 years) after an inversion trauma of the ankle. Two children were subsequently examined with magnetic resonance imaging (MRI). RESULTS: At the acute phases (6 children), US showed a hypoechoic collection with periosteal elevation at the fibular insertion of the SER. The fibular cortex and growth plate were unremarkable. The SPH was isolated in three cases and associated with an anterior talofibular ligament sprain in four. In two cases, MRI confirmed the SER periosteal avulsion and the integrity of the distal fibula. At the later phase (one child), US showed a periosteal apposition at the fibular insertion of the SER with hypoechoic thickening of the SER and power Doppler hyperaemia. CONCLUSION: This is the first sonographic description of SER avulsion as cause of SPH of the distal fibula in children. SPH in children should not be considered as pathognomonic of a Salter-Harris type 1 lesion of the distal fibula. Later, it may be responsible for persistent ankle pain. Therefore, SER may be systematically explored in children during US examination of the ankle after trauma.

Cervical foraminal steroid injections under CT guidance: retrospective study of in situ contrast aspects in a serial of 248 cases.

OBJECTIVES: To describe all the CT findings after in situ contrast injection just before steroid injection and to recognize the abnormal aspects associated with intravascular contamination. MATERIAL AND METHODS: We retrospectively evaluated 248 cervical transforaminal steroid injections done at the university hospital in Dijon, France, in 2008-2012, to treat cervicobrachial neuralgia inadequately improved by optimal medical treatment for at least 3 weeks. Features describing the opacification patterns were recorded. RESULTS: Five main nonvascular opacification patterns were identified: clumps of contrast agent outside the foramen (16 %), a crab claw pattern surrounding the ganglion (13 %), a "French" circumflex accent pattern (15 %), reflux along the needle (7 %), and facet joint capsule opacification (22 %). Concerning the situations requiring a change in needle position, intravenous injection occurred in 26 % of the patients, with a crab claw pattern in half the cases and a clump pattern in half the cases. Intraarteriolar injection was noted in two patients. CONCLUSION: CT after in situ contrast injection ensures proper needle positioning outside the blood vessels before steroid injection. Penetration of the needle tip into a vein is very common, whereas arteriolar puncture is extremely rare.

Prospective study of the reproducibility of X-rays and CT scans for assessing trochanteric fracture comminution in the elderly: a series of 110 cases.

BACKGROUND: Trochanteric fractures are common but difficult to analyse in the elderly on plain X-rays. Fixation failures are related to the severity of the comminution, but comminution and the degree of instability are not easy to determine on standard X-rays. Use of computed tomography (CT) improves assessment of complex fractures, but this finding has not been confirmed versus intraoperative data. The primary objective of this prospective study was to determine the error rate when evaluating comminution on X-rays and CT scans. The secondary objectives were to determine whether CT data on comminution and stability were consistent with intraoperative findings and to define the fracture characteristics. HYPOTHESIS: Standard X-ray assessment underestimates the complexity of trochanteric fractures and is not very reproducible. METHODS: Between January and December 2013, all proximal femur fractures in the trochanter area of patients aged 75 years or older (mean age 85) were analysed prospectively with standard X-rays and computed tomography (CT). One hundred and ten patients (88 women and 22 men) with trochanteric fractures were included in the study. Fracture stability was evaluated using the Müller AO classification; the other fracture characteristics were evaluated independently. A senior surgeon evaluated the anonymised X-rays. A radiologist specialised in musculoskeletal imaging interpreted the CT scan images. All patients underwent total hip arthroplasty (110 patients) and 104 fixations of the greater trochanter. The X-ray and CT findings were compared to the intraoperative findings (gold standard) to evaluate their reproducibility. RESULTS: The reproducibility of the X-ray evaluation was poor for comminution, with a kappa of 0.4, sensitivity of 44 % and a negative predictive value of 29 % but a positive predictive value and specificity of 100 %. The CT evaluation had a kappa of 0.94, sensitivity of 95 % and negative predictive value of 79 %. According to the AO classification, unstable fractures were found in 65 patients based on X-rays, 80 patients based on CT scan and 83 patients based on intraoperative findings. Comminution was mainly identified during surgery; it was medial in 34 % of cases, posterior in 22 % and posteromedial in 21.8 %. DISCUSSION AND CONCLUSION: In the current study, 75.4 % of fractures were complex and unstable, with medial and/or posterior comminution present in three-quarters of these fractures. X-ray assessment underestimates posterior comminution and the complexity of the fracture line and was not very reproducible. The current results of this study suggest that comminution contributes to instability and that this finding is not taken into account in the AO classification, which is not well suited for this type of fracture and raises the question of how to best evaluate and treat these fractures. LEVEL OF EVIDENCE: Prospective diagnostic study, Level III.

Carpal pseudoerosions: a plain X-ray interpretation pitfall.

OBJECTIVE: To examine in detail images of pseudoerosion of the wrist and hand on plain radiographs. MATERIAL AND METHODS: The study was conducted with 28 cadaver wrists. During a single imaging session three techniques-plain radiography, tomosynthesis, and computed tomography-were used to visualize the wrist and hand specimens. For each technique, 20 radio-ulno-carpo-metacarpal sites known to present bone erosions in rheumatoid arthritis were analyzed by two radiologists using a standard system to score the cortical bone: normal, pseudoerosion, true erosion, or other pathology. Cohen's concordance analysis was performed to determine inter-observer and intra-observer (for the senior radiologist) agreement by site and by technique. Serial sections of two cadaver specimens were examined to determine the anatomical correlation of the pseudoerosions. RESULTS: On the plain radiographs, the radiologists scored many images as pseudoerosion (7.3%), particularly in the distal ulnar portion of the capitate, the distal radial portion of the hamate, the proximal ulnar portion of the base of the third metacarpal, the proximal radial portion of the base of the fourth metacarpal, the distal ulnar portion of the hamate, and the proximal portion of the base of the fifth metacarpal. The computed tomography scan revealed that none of these doubtful images corresponded to true erosions. The anatomical correlation study showed that these images could probably be attributed to ligament insertions, thinner lamina, and enhanced cortical bone transparency. CONCLUSION: Knowledge of the anatomical carpal localizations where pseudoerosions commonly occur is a necessary prerequisite for analysis of plain radiographs performed to diagnose or monitor rheumatoid arthritis.

Prevalence and clinical significance of occult fractures in children with radiograph-negative acute ankle injury. A meta-analysis.

BACKGROUND AND PURPOSE: Plain radiographs may fail to reveal an ankle fracture in children because of developmental and anatomical characteristics. In this systematic review and meta- analysis, we estimated the prevalence of occult fractures in children with acute ankle injuries and clinical suspicion of fracture, and assessed the diagnostic accuracy of ultrasound (US) in the detection of occult fractures. METHODS: We searched the literature and included studies reporting the prevalence of occult fractures in children with acute ankle injuries and clinical suspicion of fracture. Proportion meta-analysis was performed to calculate the pooled prevalence of occult fractures. For each individual study exploring the US diagnostic accuracy, we calculated US operating characteristics. RESULTS: 9 studies (involving 187 patients) using magnetic resonance imaging (MRI) (n = 5) or late radiographs (n = 4) as reference standard were included, 2 of which also assessed the diagnostic accuracy of US. Out of the 187 children, 41 were found to have an occult fracture. The pooled prevalence of occult fractures was 24% (95% CI: 18-31). The operating characteristics for detection of occult ankle fractures by US ranged in positive likelihood ratio (LR) from 9 to 20, and in negative LR from 0.04 to 0.08. INTERPRETATION: A substantial proportion of fractures may be overlooked on plain radiographs in children with acute ankle injuries and clinical suspicion of fracture. US appears to be a promising method for detection of ankle fractures in such children when plain radiographs are negative.