Reproduction of forearm rotation dynamic using intensity-based biplane 2D-3D registration matching method.

This study aimed to reproduce and analyse the in vivo dynamic rotational motion of the forearm and to clarify forearm motion involvement and the anatomical function of the interosseous membrane (IOM). The dynamic forearm rotational motion of the radius and ulna was analysed in vivo using a novel image-matching method based on fluoroscopic and computed tomography images for intensity-based biplane two-dimensional-three-dimensional registration. Twenty upper limbs from 10 healthy volunteers were included in this study. The mean range of forearm rotation was 150 ± 26° for dominant hands and 151 ± 18° for non-dominant hands, with no significant difference observed between the two. The radius was most proximal to the maximum pronation relative to the ulna, moved distally toward 60% of the rotation range from maximum pronation, and again proximally toward supination. The mean axial translation of the radius relative to the ulna during forearm rotation was 1.8 ± 0.8 and 1.8 ± 0.9 mm for dominant and non-dominant hands, respectively. The lengths of the IOM components, excluding the central band (CB), changed rotation. The transverse CB length was maximal at approximately 50% of the rotation range from maximum pronation. Summarily, this study describes a detailed method for evaluating in vivo dynamic forearm motion and provides valuable insights into forearm kinematics and IOM function.

Opportunistic hand radiographs to screen for low forearm bone mineral density: a prospective and retrospective cohort study.

BACKGROUND: Low bone mineral density affects 53% of women over age 65 in the US, yet many are unaware and remain untreated. Underdiagnosis of forearm osteoporosis and related fragility fractures represent missed warning signs of more deadly, future fractures. This study aimed to determine if hand radiographs could serve as early, simple screening tools for predicting low forearm bone mineral density (BMD). METHODS: We evaluated posterior-anterior (PA) hand radiographs (x-rays) and Dual-energy X-ray absorptiometry (DXA) scans of 43 participants. The ratio of the intramedullary cavity to total cortical diameter of the second metacarpal (second metacarpal cortical percentage (2MCP)) was used as a potential diagnostic marker. Mixed-effects linear regression was performed to determine correlation of 2MCP with BMD from various anatomic regions. Repeated measures ANOVAs were used to compare BMD across sites. An optimal 2MCP cutoff for predicting forearm osteopenia and osteoporosis was found using Receiver Operating Curves. RESULTS: 2MCP is directly correlated with BMD in the forearm. The optimal 2MCP of 48.3% had 80% sensitivity for detecting osteoporosis of the 1/3 distal forearm. An 2MCP cutoff of 50.8% had 84% sensitivity to detect osteoporosis of the most distal forearm. Both 2MCP cutoffs were more sensitive at predicting forearm osteoporosis than femoral neck T-scores. CONCLUSIONS: These findings support the expansion of osteoporosis screening to include low-cost hand x-rays, aiming to increase diagnosis and treatment of low forearm BMD and fractures. Proposed next steps include confirming the optimal 2MCP cutoff at scale and integrating automatic 2MCP measurements into PAC systems.

Flexed elbow, abducted shoulder, forearm supinated (FABS) reconstruction from three-dimensional elbow MRI: diagnostic performance assessment in biceps head anatomy and pathology.

AIM: To determine inter-reader analysis and diagnostic performance on digitally reconstructed virtual flexed, abducted, supinated (FABS) imaging from three-dimensional (3D) isotropic elbow magnetic resonance imaging (MRI). MATERIALS AND METHODS: Six musculoskeletal radiologists independently evaluated elbow MRI images with virtual FABS reconstructions, blinded to clinical findings and final diagnoses. Each radiologist recorded a binary result as to whether the tendon was intact and if both heads were visible, along with a categorical value to the type of tear and extent of retraction in centimetres where applicable. Kappa and interclass correlation (ICC) were reported with 95% confidence intervals. Areas under the receiver operating curve (AUC) were reported. RESULTS: FABS reconstructions were obtained successfully in all 48 cases. With respect to tendon intactness, visibility of both heads, and type of tear, the Kappa values were 0.66 (0.53-0.78), 0.24 (0.12-0.37), and 0.55 (0.43-0.66), respectively. For the extent of retraction, the ICC was 0.85 (0.79-0.91) when including the tendons with and without retraction and 0.78 (0.61-0.91) when only including tendons with retraction. For tear versus no tear, AUC values were 0.82 (0.74-0.89) to 0.96 (0.91-1.01). CONCLUSION: Digital reconstruction of FABS positioning is feasible and allows good assessment of individual tendon head tears and retraction with high diagnostic performance.

Motion-resistant three-wavelength spatial frequency domain imaging system with ambient light suppression using an 8-tap CMOS image sensor.

Significance: We present a motion-resistant three-wavelength spatial frequency domain imaging (SFDI) system with ambient light suppression using an 8-tap complementary metal-oxide semiconductor (CMOS) image sensor (CIS) developed at Shizuoka University. The system addresses limitations in conventional SFDI systems, enabling reliable measurements in challenging imaging scenarios that are closer to real-world conditions. Aim: Our study demonstrates a three-wavelength SFDI system based on an 8-tap CIS. We demonstrate and evaluate the system's capability of mitigating motion artifacts and ambient light bias through tissue phantom reflectance experiments and in vivo volar forearm experiments. Approach: We incorporated the Hilbert transform to reduce the required number of projected patterns per wavelength from three to two per spatial frequency. The 8-tap image sensor has eight charge storage diodes per pixel; therefore, simultaneous image acquisition of eight images based on multi-exposure is possible. Taking advantage of this feature, the sensor simultaneously acquires images for planar illumination, sinusoidal pattern projection at three wavelengths, and ambient light. The ambient light bias is eliminated by subtracting the ambient light image from the others. Motion artifacts are suppressed by reducing the exposure and projection time for each pattern while maintaining sufficient signal levels by repeating the exposure. The system is compared to a conventional SFDI system in tissue phantom experiments and then in vivo measurements of human volar forearms. Results: The 8-tap image sensor-based SFDI system achieved an acquisition rate of 9.4 frame sets per second, with three repeated exposures during each accumulation period. The diffuse reflectance maps of three different tissue phantoms using the conventional SFDI system and the 8-tap image sensor-based SFDI system showed good agreement except for high scattering phantoms. For the in vivo volar forearm measurements, our system successfully measured total hemoglobin concentration, tissue oxygen saturation, and reduced scattering coefficient maps of the subject during motion (16.5 cm/s) and under ambient light (28.9 lx), exhibiting fewer motion artifacts compared with the conventional SFDI. Conclusions: We demonstrated the potential for motion-resistant three-wavelength SFDI system with ambient light suppression using an 8-tap CIS.

In-Vivo Electrical Properties Estimation of Biological Tissues by Means of a Multi-Step Microwave Tomography Approach.

The accurate quantitative estimation of the electromagnetic properties of tissues can serve important diagnostic and therapeutic medical purposes. Quantitative microwave tomography is an imaging modality that can provide maps of the in-vivo electromagnetic properties of the imaged tissues, i.e. both the permittivity and the electric conductivity. A multi-step microwave tomography approach is proposed for the accurate retrieval of such spatial maps of biological tissues. The underlying idea behind the new imaging approach is to progressively add details to the maps in a step-wise fashion starting from single-frequency qualitative reconstructions. Multi-frequency microwave data is utilized strategically in the final stage. The approach results in improved accuracy of the reconstructions compared to inversion of the data in a single step. As a case study, the proposed workflow was tested on an experimental microwave data set collected for the imaging of the human forearm. The human forearm is a good test case as it contains several soft tissues as well as bone, exhibiting a wide range of values for the electrical properties.

The effect of forearm rotation on the bone mineral density measurements of the distal radius.

INTRODUCTION: Forearm dual-energy X-ray absorptiometry (DXA) is often performed in clinics where central DXA is unavailable. Accurate bone mineral density (BMD) measurement is crucial for clinical assessment. Forearm rotation can affect BMD measurements, but this effect remains uncertain. Thus, we aimed to conduct a simulation study using CT images to clarify the effect of forearm rotation on BMD measurements. MATERIALS AND METHODS: Forearm CT images of 60 women were analyzed. BMD was measured at the total, ultra-distal (UD), mid-distal (MD), and distal 33% radius regions with the radius located at the neutral position using digitally reconstructed radiographs generated from CT images. Then, the rotation was altered from - 30° to 30° (supination set as positive) with a one-degree increment, and the percent BMD changes from the neutral position were quantified for all regions at each angle for each patient. RESULTS: The maximum mean BMD changes were 5.8%, 7.0%, 6.2%, and 7.2% for the total, UD, MD, and distal 33% radius regions, respectively. The analysis of the absolute values of the percent BMD changes from the neutral position showed that BMD changes of all patients remained within 2% when the rotation was between - 5° and 7° for the total region, between - 3° and 2° for the UD region, between - 4° and 3° for the MD region, and between - 3° and 1° for the distal 33% radius region. CONCLUSION: Subtle rotational changes affected the BMD measurement of each region. The results showed the importance of forearm positioning when measuring the distal radius BMD.

Length changes in the distal oblique band during forearm rotation measured using four-dimensional CT: an in vivo study.

Length change in the distal oblique band during forearm rotation was measured using four-dimensional CT in seven volunteers. There was no significant change in length, which provides more theoretical support for distal oblique band reinforcement for treatment of instability of the distal radioulnar joint.

Does forearm referencing using a retroversion guide achieve the targeted retroversion of the humeral component in reverse shoulder arthroplasty?

BACKGROUND: Component positioning affects clinical outcomes of reverse shoulder arthroplasty, which necessitates an implantation technique that is reproducible, consistent, and reliable. This study aims to assess the accuracy and precision of positioning the humeral component in planned retroversion using a forearm referencing guide. METHODS: Computed tomography scans of 54 patients (27 males and 27 females) who underwent primary reverse shoulder arthroplasty for osteoarthritis or cuff tear arthropathy were evaluated. A standardized surgical technique was used to place the humeral stem in 15° of retroversion. Version was assessed intraoperatively visualizing the retroversion guide from above and referencing the forearm axis. Metal subtraction techniques from postoperative computed tomography images allowed for the generation of 3D models of the humerus and for evaluation of the humeral component position. Anatomical humeral plane and implant planes were defined and the retroversion 3D angle between identified planes was recorded for each patient. Accuracy and precision were assessed. A subgroup analysis evaluated differences between male and female patients. RESULTS: The humeral retroversion angle ranged from 0.9° to 22.8°. The majority (81%) of the measurements were less than 15°. Mean retroversion angle (±SD) was 9.9° ± 5.8° (95% CI 8.4°-11.5°) with a mean percent error with respect to 15° of -34% ± 38 (95% CI -23 to -44). In the male subgroup (n = 27, range 3.8°-22.5°), the mean retroversion angle was 11.9° ± 5.4° (95% CI 9.8°-14.1°) with a mean percent error with respect to 15° of -21% ± 36 (95% CI -6 to -35). In the female subgroup (n = 27, range 0.9°-22.8°), mean retroversion angle was 8.0° ± 5.5° (95% CI 5.8°-10.1°) and the mean percent error with respect to 15° was -47% ± 36 (95% CI -32 to -61). The differences between the 2 gender groups were statistically significant (P = .006). CONCLUSION: Referencing the forearm using an extramedullary forearm referencing system to position the humeral stem in a desired retroversion is neither accurate nor precise. There is a nonnegligible tendency to achieve a lower retroversion than planned, and the error is more marked in females.

Domain Adaptation and Feature Fusion for the Detection of Abnormalities in X-Ray Forearm Images.

The main challenge in adopting deep learning models is limited data for training, which can lead to poor generalization and a high risk of overfitting, particularly when detecting forearm abnormalities in X-ray images. Transfer learning from ImageNet is commonly used to address these issues. However, this technique is ineffective for grayscale medical imaging because of a mismatch between the learned features. To mitigate this issue, we propose a domain adaptation deep TL approach that involves training six pre-trained ImageNet models on a large number of X-ray images from various body parts, then fine-tuning the models on a target dataset of forearm X-ray images. Furthermore, the feature fusion technique combines the extracted features with deep neural models to train machine learning classifiers. Gradient-based class activation heat map (Grad CAM) was used to verify the accuracy of our results. This method allows us to see which parts of an image the model uses to make its classification decisions. The statically results and Grad CAM have shown that the proposed TL approach is able to alleviate the domain mismatch problem and is more accurate in their decision-making compared to models that were trained using the ImageNet TL technique, achieving an accuracy of 90.7%, an F1-score of 90.6%, and a Cohen's kappa of 81.3%. These results indicate that the proposed approach effectively improved the performance of the employed models individually and with the fusion technique. It helped to reduce the domain mismatch between the source of TL and the target task.

Creation of the Forearm 3D-Model with Veins from Transversal Ultrasonography Image Sequence.

This study developed an automatic detection algorithm of vessel and skin regions in a transversal ultrasonography image on the arm. We also developed an algorithm to generate a 3D model from detected areas to assist vein puncture. In the algorithm, the vessel's candidate regions in the ultrasonography image were detected using U-Net or Mask R-CNN, which are a kind of deep learning method for segmentation. Then vessel regions were selected among the candidates based on continuous properties in an image sequence. The skin regions were also detected. The 3D polygon data was created from paired pixels in sequential images. The experiments demonstrated that Mask R-CNN could correctly estimate the branch of vessel which were difficult to identify accurate region separately using U-Net, and achieved an overall IoU of 80%. The confirmation experiment of 3D model demonstrated that generated model have enough feasibility for assessment of appropriate veins and locations for puncture.Clinical relevance-The developed 3D model generation from ultrasonography images will be useful for support to identify the appropriate veins for puncture.

Precision errors and least significant changes in paediatric forearm measurements of bone density, mass, dimensions, mechanostat parameters and soft tissue composition by Stratec XCT-2000L.

OBJECTIVES: The peripheral quantitative computed tomography (pQCT) is gaining popularity in the field of paediatric densitometry, however, very little is known about the precision errors of this method in diseased children. The aim of the study was to evaluate the precision errors of bone density, mass, dimensions, strength, mechanostat parameters and soft tissue at the forearm in diseased children. METHODS: Stratec XCT 2000L apparatus was used. The measurement sites were 4% and 66% of the forearm length. The study group consisted of 60 patients (31 girls) aged 5,7-18,0 yrs. RESULTS: We observed week relationships between precision errors and body size with r from -0,37 to 0,28. Relative precision errors (CV%RMS) were from 0,85% for radius 66% cortical bone density to 3,82% for fat cross-sectional area to muscle cross-sectional area ratio. Least significant change (LSC) was from 2,73% to 10,59%, respectively. CONCLUSION: Presented study reveal pQCT method at the forearm in diseased children as relatively precise technique. The results may help with planning and interpretation of pQCT studies in diseased children.

Assessment of forearm muscles with ultrasound shear wave elastography in patients with acromegaly.

PURPOSE: The effects of acromegaly on soft tissues, bones and joints are well-documented, but information on its effects on muscle mass and quality remains limited. The primary goal of this study is to assess the sonoelastographic features of forearm muscles in patients with acromegaly. METHOD: Forty-five patients with acromegaly and 45 healthy controls similar in terms of gender, age, and body mass index (BMI) were included in a single-center, multidisciplinary, cross-sectional study. The body composition was analyzed using bioelectrical impedance analysis (BIA), and height-adjusted appendicular skeletal muscle index (hSMI) was calculated. The dominant hand's grip strength was also measured. Two radiologists specialized in the musculoskeletal system employed ultrasound shear wave elastography (SWE) to assess the thickness and stiffness of brachioradialis and biceps brachii muscles. RESULTS: The acromegaly group had significantly higher thickness of both the biceps brachii (p = 0.034) and brachioradialis muscle (p = 0.046) than the control group. However, the stiffness of the biceps brachii (p = 0.001) and brachioradialis muscle (p = 0.001) was lower in the acromegaly group than in the control group. Disease activity has not caused a significant difference in muscle thickness and stiffness in the acromegaly group (p > 0.05). The acromegaly group had a higher hSMI (p = 0.004) than the control group. The hand grip strength was similar between the acromegaly and control group (p = 0.594). CONCLUSION: The patients with acromegaly have an increased muscle thickness but decreased muscle stiffness in the forearm muscles responsible for elbow flexion. Acromegaly can lead to a permanent deterioration of the muscular structure regardless of the disease activity.

Elasticity of the Forearm Flexor-Pronator Muscles as a Risk Factor for Medial Elbow Injuries in Young Baseball Players: A Prospective Cohort Study of 314 Players.

BACKGROUND: Young baseball players with medial elbow injuries are known to have high forearm flexor-pronator muscle elasticity; however, the causal relationship between forearm muscle elasticity and the occurrence of medial elbow injuries remains unclear. PURPOSE/HYPOTHESIS: The purpose of this study was to determine whether the forearm flexor-pronator muscle elasticity is a risk factor for medial elbow injury in young baseball players. It was hypothesized that high flexor carpi ulnaris (FCU) elasticity would be a risk factor for medial elbow injuries. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Young baseball players (aged 9-12 years) with no history of elbow injuries underwent examination during which the strain ratios (SRs) of the pronator teres, flexor digitorum superficialis, and FCU muscles were measured using ultrasound strain elastography as an index of elasticity. Additionally, the participants completed a questionnaire assessing age, height, weight, months of experience as a baseball player, position in baseball, number of training days per week, number of throws per day, and elbow pain during throwing; then the range of motion of the shoulder and hip internal/external rotation were measured. One year after the baseline measurements, the occurrence of new medial elbow injuries was evaluated. Multivariate logistic regression analysis was subsequently conducted to determine risk factors for medial elbow injuries. Cutoff points for significant SR values obtained from the multivariate logistic regression analysis were calculated using the receiver operating characteristic curve. RESULTS: Of the 314 players, 76 (24.2%) were diagnosed with medial elbow injury. Multivariate logistic regression analysis showed that a 0.1 increase in the SR of the FCU muscle (odds ratio [OR], 1.211; 95% CI, 1.116-1.314) and number of throws per day (OR, 1.012; 95% CI, 1.001-1.022) were significantly associated with medial elbow injuries. Receiver operating characteristic curve analyses revealed that the optimal cutoff for the SR of the FCU muscle was 0.920 (area under the curve, 0.694; sensitivity, 75.0%; specificity, 56.7%). CONCLUSION: Increased FCU elasticity is a risk factor for medial elbow injury. Evaluation of the FCU elasticity may be useful in identifying young baseball players at high risk of medial elbow injuries and may facilitate prevention of medial elbow injury. As shown by the results of multivariate logistic regression analysis, FCU elasticity itself may be useful in identifying young baseball players at high risk of elbow injuries. However, we believe that other factors, such as the number of pitches per day, need to be considered to improve its accuracy.

Multiexposure laser speckle contrast analysis system calibration limited by perfusion-dependent scattering on the skin.

Significance: Application of multiexposure speckle contrast imaging (MESI) methods for perfusion measurements can correct for the contribution of static scattering of the skin, at the expense of reduced temporal resolution as compared to classical single-exposure methods. Persistence of tissue scattering properties during the measurements could allow for an initial calibration and enhancement of the temporal resolution of the measurements. Aim: We aim to study the influence of the perfusion on the light scattering of the forearm skin and to use the obtained data for the enhancement of the temporal resolution. Approach: A wide range of skin perfusion states was induced while monitoring the changes in the dynamic range of the exposure-dependent contrast. Different measurement and evaluation methods were tested based on an initial MESI calibration followed by image recording with reduced number of exposure time values. Results: The changes in the skin perfusion can alter not only the contribution of the static scattering to the speckle images but also the short-exposure time contrast limit. Conclusions: The perfusion-dependent scattering of the skin can invalidate the precalibrations (e.g., ß calibration) characterizing the combination of the given tissue and the measurement system.

Non-invasive assessment of muscle compartment elasticity by pressure-related ultrasound in pediatric trauma: a prospective clinical study in 25 cases of forearm shaft fractures.

BACKGROUND: Soft-tissue swelling after limb fractures in pediatric patients is well known to be a risk factor for developing acute compartment syndrome (ACS). Clinical assessment alone is uncertain in specific cases. Recently, we proposed a non-invasive ultrasound-based method to objectify muscle compartment elasticity for monitoring. We hypothesize a strong correlation between the soft-tissue swelling after stabilization of upper limb fractures and the compartment elasticity objectified with a novel ultrasound-based approach in pediatric trauma. PATIENTS AND METHODS: In a prospective clinical study, children suffering forearm fractures but not developing an ACS were included. The muscle compartment elasticity of the m. flexor carpi ulnaris was assessed after surgical intervention by a non-invasive, ultrasound-based method resulting in a relative elasticity (RE in %) in both the control (healthy limb) and study group (fractured limb). Soft-tissue swelling was categorized in four different levels (0-3) and correlated with the resulting RE (%). RESULTS: The RE in the study group (15.67%, SD ± 3.06) showed a significantly decreased level (p < 0.001) compared with the control (22.77%, SD ± 5.4). The categorized grade of soft-tissue swelling resulted in a moderate correlation with the RE (rs = 0.474). CONCLUSIONS: The presented study appears to represent a novel approach to assess the posttraumatic pressure changes in a muscle compartment after fracture stabilization non-invasively. In this first clinical study in pediatric cases, our measurement method represents a low-cost, easy, and secure approach that has the potential to substitute invasive measurement of suspected ACS in muscle compartment conditions. Further investigations in lager cohorts are required to prove its daily clinical practicability and to confirm the expected reliability.

Defining Normal Reference Range For The Cross Sectional Area Of The Median Nerve At The Wrist And Forearm Using High-Resolution Ultrasonography In Asymptomatic Pakistani Adults.

BACKGROUND: Carpal tunnel syndrome (CTS) can be diagnosed easily on ultrasonography (USG); which is a cheap, non-invasive and readily available modality. However, there is wide normal variation in the normal values of cross-sectional area (CSA) of median nerve among different populations; therefore, its necessary to establish a normal range of variability in median nerve dimensions in different populations. METHODS: A total of 500 asymptomatic patients i.e., 1000 median nerves were evaluated at the distal wrist crease and mid-forearm by 3 expert radiologists independently. All patients having a positive nerve conduction study or history of carpal tunnel syndrome and wrist trauma were excluded. Ultrasound was performed with a 7.5-15 MHz high-frequency linear probe. SPSS v 20 was used to analyze data. RESULTS: The study population had a mean age of 31.40±10.11 years with a female-to-male ratio of 1.36:1. Mean BMI was 22.15±4.34 Kg/m2 . The mean cross section area of the median nerve at the right wrist was calculated to be 6.8±1.96 mm2 and the left wrist was 6.6±1.96 mm2 . The mean median nerve cross-section area at the right mid-forearm was 5.3±1.46 mm2 and the left mid-forearm was 5.2±1.50 mm2 . A decrease in mean median nerve cross-section areas was noted by moving from wrist to forearm. Similarly, males showed higher median nerve CSA than females. CONCLUSIONS: Mean median nerve cross-section area was found to be different from Western countries. This warrants the utilization of the data of the Pakistani population to establish our own normal reference range for median nerve cross-sectional area to avoid misdiagnoses.

Individual Muscle Force Estimation in the Human Forearm Using Multi-Muscle MR Elastography (MM-MRE).

OBJECTIVE: To establish the sensitivity of magnetic resonance elastography (MRE) to active muscle contraction in multiple muscles of the forearm. METHODS: We combined MRE of forearm muscles with an MRI-compatible device, the MREbot, to simultaneously measure the mechanical properties of tissues in the forearm and the torque applied by the wrist joint during isometric tasks. We measured shear wave speed of thirteen forearm muscles via MRE in a series of contractile states and wrist postures and fit these outputs to a force estimation algorithm based on a musculoskeletal model. RESULTS: Shear wave speed changed significantly upon several factors, including whether the muscle was recruited as an agonist or antagonist (p = 0.0019), torque amplitude (p = <0.0001), and wrist posture (p = 0.0002). Shear wave speed increased significantly during both agonist (p = <0.0001) and antagonist (p = 0.0448) contraction. Additionally, there was a greater increase in shear wave speed at greater levels of loading. The variations due to these factors indicate the sensitivity to functional loading of muscle. Under the assumption of a quadratic relationship between shear wave speed and muscle force, MRE measurements accounted for an average of 70% of the variance in the measured joint torque. CONCLUSION: This study shows the ability of MM-MRE to capture variations in individual muscle shear wave speed due to muscle activation and presents a method to estimate individual muscle force through MM-MRE derived measurements of shear wave speed. SIGNIFICANCE: MM-MRE could be used to establish normal and abnormal muscle co-contraction patterns in muscles of the forearm controlling hand and wrist function.

A rare case of an intratendinous ganglion cyst extending into the muscle belly of flexor carpi radialis: a case report and review of the literature.

ITGCs (intratendinous ganglion cysts) involving the flexor compartment of the wrist are uncommon, and reports are scarce in the literature. The differential diagnosis is wide and can mimic sinister lesions. We report a case of a 62-year-old male, that presented to our tertiary orthopaedic oncology service with an intratendinous ganglion cyst, extending into the muscle belly of flexor carpi radialis. We describe this rare presentation and review the literature.

Deep branch of the radial nerve: effect of pronation/supination on longitudinal nerve alignment.

OBJECTIVE: To evaluate the effect of maximal pronation and supination of the forearm on the alignment and anatomic relationship of the deep branch of the radial nerve (DBRN) at the superior arcade of the supinator muscle (SASM) by using high-resolution ultrasound (HRUS). MATERIALS AND METHODS: In this cross-sectional study, HRUS in the long axis of the DBRN was performed in asymptomatic participants enrolled from March to August 2021. DBRN alignment was evaluated by measuring angles of the nerve in maximal pronation and maximal supination of the forearm independently by two musculoskeletal radiologists. Forearm range of motion and biometric measurements were recorded. Student t, Shapiro-Wilk, Pearson correlation, reliability analyses, and Kruskal-Wallis test were used. RESULTS: The study population included 110 nerves from 55 asymptomatic participants (median age, 37.0 years; age range, 16-63 years; 29 [52.7%] women). There was a statistically significant difference between the DBRN angle in maximal supination and maximal pronation (Reader 1: 95% CI: 5.74, 8.21, p < 0.001, and Reader 2: 95% CI: 5.82, 8.37, p < 0.001). The mean difference between the angles in maximal supination and maximal pronation was approximately 7° for both readers. ICC was very good for intraobserver agreement (Reader1: r ≥ 0.92, p < 0.001; Reader 2: r ≥ 0.93, p < 0.001), as well as for interobserver agreement (phase 1: r ≥ 0.87, p < 0.001; phase 2: r ≥ 0.90, p < 0.001). CONCLUSION: The extremes of the rotational movement of the forearm affect the longitudinal morphology and anatomic relationships of the DBRN, primarily demonstrating the convergence of the nerve towards the SASM in maximal pronation and divergence in maximal supination.

The clinical necessity of a distal forearm DEXA scan for predicting distal radius fracture in elderly females: a retrospective case-control study.

BACKGROUND: Recent studies have demonstrated that the distal forearm dual-energy X-ray absorptiometry (DEXA) scan might be a better method for screening bone mineral density (BMD) and the risk of a distal forearm fracture, compared with a central DEXA scan. Therefore, the purpose of this study was to determine the effectiveness of a distal forearm DEXA scan for predicting the occurrence of a distal radius fracture (DRF) in elderly females who were not initially diagnosed with osteoporosis after a central DEXA scan. METHODS: Among the female patients who visited our institutes and who were over 50 years old and underwent DEXA scans at 3 sites (lumbar spine, proximal femur, and distal forearm), 228 patients with DRF (group 1) and 228 propensity score-matched patients without fractures (group 2) were included in this study. The patients' general characteristics, BMD, and T-scores were compared. The odds ratios (OR) of each measurement and correlation ratio among BMD values of the different sites were evaluated. RESULTS: The distal forearm T-score of the elderly females with DRF (group 1) was significantly lower than that of the control group (group 2) (p < 0.001 for the one-third radius and ultradistal radius measurements). BMD measured during the distal forearm DEXA scan was a better predictor of DRF risk than BMD measured during the central DEXA (OR = 2.33; p = 0.031 for the one-third radius, and OR = 3.98; p < 0.001 for the ultradistal radius). The distal one-third radius BMD was correlated with hip BMD, rather than lumbar BMD (p < 0.05 in each group). CONCLUSION: Performing a distal forearm DEXA scan in addition to a central DEXA scan appears to be clinically significant for detecting the low BMD in the distal radius, which is associated with osteoporotic DRF in elderly females. LEVEL OF EVIDENCE: III; case-control study.