Development of the Interosseous Muscles of the Human Hand: Morphological and Functional Aspects of the Terminal Insertion.

INTRODUCTION: To date, there have been no studies conducted on the development of interosseous muscles (IO) in the human hand. This study aimed to investigate the development of these muscles in order to clarify their terminal insertions and their relationship with the metacarpophalangeal joints. METHODS: Serial sections of 25 human specimens (9 embryos and 16 fetuses) between the 7th and 14th weeks of development, sourced from the Collection of the Department of Anatomy and Embryology at UCM Faculty of Medicine, were analyzed bilaterally using a conventional optical microscope. RESULTS: Our findings revealed that, during the 7th week of development, the metacarpophalangeal interzone mesenchyme extended into the extensor apparatus of the fingers. Furthermore, we observed that the joint capsule and the tendon of the IO derive from the articular interzone mesenchyme. By the end of the 7th week, corresponding to Carnegie stage 21, the myotendinous junction appeared, initiating cavitation of the metacarpophalangeal joint. During the fetal period, the terminal insertions of the IO were identified: both the dorsal interosseous (DI) and palmar interosseous (PI) muscles insert into the metacarpophalangeal joint capsule and establish a connection with the volar plate located at the base of the proximal phalanx and the extensor apparatus. Some muscle fibers also attach to the joint capsule at the level of the proximal synovial cul-de-sac. The functional implications of these findings are discussed within this work. CONCLUSION: This study provides the first detailed description of the development of the interosseous muscles in the human hand.

Whole-hand perceptual maps of joint location.

Hands play a fundamental role in everyday behaviour. Nevertheless, healthy adults show striking misrepresentations of their hands which have been documented by a wide range of studies addressing various aspects of body representation. For example, when asked to indicate the location within the hand of the knuckles, people place them substantially farther forward than they actually are. Previous research, however, has focused exclusively on the knuckles at the base of each finger, not considering the other knuckles in the fingers. This study, therefore, aimed to investigate conceptual knowledge of the structure of the whole hand, by investigating judgements of the location of all 14 knuckle joints in the hand. Participants localised each of the 14 knuckles of their own hand (Experiment 1) or of the experimenter's hand (Experiment 2) on a hand silhouette. We measured whether there are systematic localisation biases. The results showed highly similar pattern of mislocalisation for the knuckles of one's own hand and those of another person's hand, suggesting that people share an abstract conceptual knowledge about the hand structure. In line with previous reports, we showed that the metacarpophalangeal joints at the base of the fingers are judged as substantially father forward in the hand than they actually are. Moreover, for the first time we showed a gradient of this bias, with progressive reduction of distal bias from more proximal to more distal joints. In sum, people think their finger segments are roughly the same, and that their fingers are shorter than they are.

Modified metacarpal shortening osteotomy of the midcarpal bone for preserving metacarpophalangeal joints in patients with rheumatoid arthritis.

Recent advances in medication choices have strikingly improved the management of rheumatoid arthritis. However, medication alone cannot place back already deformed joints. Thus, to prevent metacarpophalangeal (MP) joint destruction, joint deformity correction should be considered since mechanical stress induced by finger motions will eventually destruct the undestructed joint, with a possibility of recurrence and future implant arthroplasty in mind since RA still remains as a progressive disease. We report a modified metacarpal shortening osteotomy for correcting MP joint deformity. The advantage of our technique over previous osteotomies is that it easily allows for subsequent implant arthroplasty even after the recurrence of joint deformity/destruction. Major modifications include that the metacarpal is shortened at its mid-shaft and the osteotomy is performed vertical to the shaft and fixed with surgical wiring. We believe that combination therapy consisting of medication and surgery is preferable to prevent joint destruction, even in this age of biological agents.

Segmentation and quantification of bone erosions in high-resolution peripheral quantitative computed tomography datasets of the metacarpophalangeal joints of patients with rheumatoid arthritis.

OBJECTIVE: To develop a precise three-dimensional (3D) segmentation technique for bone erosions in high-resolution peripheral quantitative CT (HR-pQCT) datasets to measure their volume, surface area and shape parameters. Assessment of bone erosions in patients with RA is important for diagnosis and evaluation of treatment efficacy. HR-pQCT allows quantifying periarticular bone loss in arthritis. METHODS: HR-pQCT scans with a spatial resolution of about 120 µm of the second to fourth metacarpophalangeal joints were acquired in patients with RA. Erosions were identified by placing a seed point in each of them. After applying 3D segmentation, the volume, surface area and sphericity of erosions were calculated. Results were compared with an approximation method using manual measurements. Intra- and interoperator precision analysis was performed for both the 3D segmentation and the manual technique. RESULTS: Forty-three erosions were assessed in 18 datasets. Intra- and interoperator precisions (RMSCV/RMSSD) for erosion volume were 5.66%/0.49 mm(3) and 7.76%/0.76 mm(3), respectively. The correlation between manual measurements and their simulation using segmentation volumes was r = 0.87. Precision errors for the manual method were 15.39% and 0.36 mm(3), respectively. CONCLUSION: We developed a new precise 3D segmentation technique for quantification of bone erosions in HR-pQCT datasets that correlates to the volume, shape and surface area of the erosion. The technique allows fast and effective measurement of the erosion size and could therefore be helpful for rapid and quantitative assessment of erosion size.

Computer Assisted Bone Age Estimation Using Dimensions of Metacarpal Bones and Metacarpophalangeal Joints Based on Neural Network.

Statement of the Problem: Bone age is a more accurate assessment for biologic development than chronological age. The most common method for bone age estimation is using Pyle and Greulich Atlas. Today, computer-based techniques are becoming more favorable among investigators. However, the morphological features in Greulich and Pyle method are difficult to be converted into quantitative measures. During recent years, metacarpal bones and metacarpophalangeal joints dimensions were shown to be highly correlated with skeletal age. Purpose: In this study, we have evaluated the accuracy and reliability of a trained neural network for bone age estimation with quantitative and recently introduced related data, including chronological age, height, trunk height, weight, metacarpal bones, and metacarpophalangeal joints dimensions. Materials and Method: In this cross sectional retrospective study, aneural network, using MATLAB, was utilized to determine bone age by employing quantitative features for 304 subjects. To evaluate the accuracy of age estimation software, paired t-test, and inter-class correlation was used. Results: The difference between the mean bone ages determined by the radiologists and the mean bone ages assessed by the age estimation software was not significant (p Value= 0.119 in male subjects and p= 0.922 in female subjects). The results from the software and radiologists showed a strong correlation -ICC=0.990 in male subjects and ICC=0.986 in female subjects (p< 0.001). Conclusion: The results have shown an acceptable accuracy in bone age estimation with training neural network and using dimensions of bones and joints.

People with higher systemizing traits have wider right hands.

Introduction: Various genetic mutations have been implicated in autism spectrum disorder (ASD). Some candidate genes for ASD are known to be related to signal transduction and may be involved in hand development as well as neurodevelopment. Therefore, although subtle, anatomical variations in hand configurations may be observed in individuals with ASD. However, except for research on the finger ratio, which has been suggested to be related to prenatal sex hormone exposure, only few studies have been conducted. Given the spectrum characteristics of ASD, we explored whether hand configurations are associated with ASD-related traits in the general population. Methods: Photographs of the dorsal surface of each hand were obtained, and the distances between the metacarpophalangeal joints and finger lengths were measured. The Autism Spectrum Quotient, Empathy Quotient, and Systemizing Quotient were used to evaluate ASD-related traits. Results: We found a significant positive correlation between the aspect ratio of the right hand and the Systemizing Quotient score: individuals with a larger width relative to the finger length showed more systemizing traits. Discussion: These findings suggest that gene polymorphisms or prenatal sex hormone exposure may underlie the relationship between systemizing traits and hand configurations.

Evaluating high-resolution computed tomography derived 3-D joint space metrics of the metacarpophalangeal joints between rheumatoid arthritis and age- and sex-matched control participants.

Introduction: Rheumatoid arthritis (RA) is commonly characterized by joint space narrowing. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides unparalleled in vivo visualization and quantification of joint space in extremity joints commonly affected by RA, such as the 2nd and 3rd metacarpophalangeal joints. However, age, sex, and obesity can also influence joint space narrowing. Thus, this study aimed to determine whether HR-pQCT joint space metrics could distinguish between RA patients and controls, and determine the effects of age, sex and body mass index (BMI) on these joint space metrics. Methods: HR-pQCT joint space metrics (volume, width, standard deviation of width, maximum/minimum width, and asymmetry) were acquired from RA patients and age-and sex-matched healthy control participants 2nd and 3rd MCP joints. Joint health and functionality were assessed with ultrasound (i.e., effusion and inflammation), hand function tests, and questionnaires. Results: HR-pQCT-derived 3D joint space metrics were not significantly different between RA and control groups (p > 0.05), despite significant differences in inflammation and joint function (p < 0.05). Joint space volume, mean joint space width (JSW), maximum JSW, minimum JSW were larger in males than females (p < 0.05), while maximum JSW decreased with age. No significant association between joint space metrics and BMI were found. Conclusion: HR-pQCT did not detect group level differences between RA and age-and sex-matched controls. Further research is necessary to determine whether this is due to a true lack of group level differences due to well-controlled RA, or the inability of HR-pQCT to detect a difference.

Insights into the Age Dependency of Compositional MR Biomarkers Quantifying the Health Status of Cartilage in Metacarpophalangeal Joints.

(1) Background: We aim to investigate age-related changes in cartilage structure and composition in the metacarpophalangeal (MCP) joints using magnetic resonance (MR) biomarkers. (2) Methods: The cartilage tissue of 90 MCP joints from 30 volunteers without any signs of destruction or inflammation was examined using T1, T2, and T1ρ compositional MR imaging techniques on a 3 Tesla clinical scanner and correlated with age. (3) Results: The T1ρ and T2 relaxation times showed a significant correlation with age (T1ρ: Kendall-τ-b = 0.3, p < 0.001; T2: Kendall-τ-b = 0.2, p = 0.01). No significant correlation was observed for T1 as a function of age (T1: Kendall-τ-b = 0.12, p = 0.13). (4) Conclusions: Our data show an increase in T1ρ and T2 relaxation times with age. We hypothesize that this increase is due to age-related changes in cartilage structure and composition. In future examinations of cartilage using compositional MRI, especially T1ρ and T2 techniques, e.g., in patients with osteoarthritis or rheumatoid arthritis, the age of the patients should be taken into account.

Primary Arthrodesis of Non-thumb Metacarpophalangeal Joints of the Hand: Clinical and Patient-Reported Outcomes.

BACKGROUND: Metacarpophalangeal (MCP) joint arthritis is common secondary to a variety of inflammatory, degenerative, and traumatic causes. Although MCP arthroplasty is more common for the second to fifth digits, primary arthrodesis can be used for high-demand patients with arthritis or unsalvageable fractures of the MCP joint. There has been limited recent studies on the outcomes of these patients. METHODS: A retrospective review of 38 fingers in 27 patients with primary arthrodesis from 1990 to 2020 was conducted. The major outcomes were complications, reoperations, radiographic union, and time to union. Patient-reported outcomes including the Michigan Hand Outcomes Questionnaire and a questionnaire specific to the operative MCP joint were collected. RESULTS: Rate of radiographic union was 84% including revisions. The average time to union was 3.6 months. Rates of complications, reoperation, and amputation were 26%, 16%, and 7%, respectively. Arthrodesis as part of emergent trauma reconstruction was significantly more likely to result in reoperation (50% vs 7%) and complication (63% vs 17%) than chronic arthritis. Patient-reported outcomes were fair to good with improvement in pain (79%), function (66%), and appearance (40%). Sixty-six percent (66%) of patients were satisfied with their surgery, and 73% would repeat the surgery. CONCLUSION: Arthrodesis for unsalvageable MCP fractures was associated with higher rates of reoperation and complication than inflammatory or degenerative arthritis. Excluding emergent trauma, MCP fusion was reliable with a reoperation rate of 7% and a modest complication rate of 17%. Patients rated reasonable levels of satisfaction and willingness to repeat the procedure despite complications.

Evaluation of bone erosion in rheumatoid arthritis patients by high-resolution peripheral quantitative computed tomography scans: Comparison between two semi-automated programs in a three-dimensional setting.

AIM: The aim of this study was to compare OsiriX software with the previous published Medical Image Analysis Framework (MIAF) method to assess the volume of erosion in patients with rheumatoid arthritis (RA). METHODS: Forty RA patients underwent high-resolution peripheral quantitative computed tomography scans of the second and third metacarpophalangeal joints, and thirty-four patients with any bone erosion were enrolled. Two techniques were applied to erosion evaluation: (a) semi-automated MIAF software, and (b) semi-automated segmentation by free open-source Digital Imaging and Communications in Medicine viewer, OsiriX software. MIAF has been published before, but this is the first time that OsiriX has been used in this way in rheumatology. Bland & Altman plots described agreement between methods. RESULTS: Forty-eight erosions from 34 patients were analyzed. Mean age was 40.74 ± 5.32 years and mean disease duration was 10.68 ± 4.96 years. Both methods demonstrated a strong correlation regarding erosion volume (r = 0.96, P < 0.001). Median (interquartile range) of erosion volume was 12.14 (4.5-36.07) when MIAF was considered, and 11.80 (3.45-29.42) when the OsiriX tool was used (P = 0.139). MIAF and OsiriX showed good agreement when the Bland & Altman plot was performed. Evaluation by MIAF took 22.69 ± 6.71 minutes, whereas OsiriX took only 2.62 ± 1.09 minutes (P < 0.001). CONCLUSION: The three-dimensional segmentation of bone erosions can be done by both MIAF and OsiriX software with good agreement. However, because OsiriX is a widespread tool and faster, its method seems to be more feasible for evaluating peripheral bone damage, especially bone erosions.

Correlation between Skeletal Age and Metacarpal Bones and Metacarpophalangeal Joints Dimensions.

STATEMENT OF THE PROBLEM: Currently, two major methods have been introduced for bone age assessment using left hand radiography. The first approach is Greulich and Pyle, which is very subjective. The second method is Tanner and Whitehouse, which is very time consuming and its morphological criteria are not quantitative, therefore it is hardly used. PURPOSE: The purpose of this study is to evaluate the relationship between skeletal age and bone size and joint space measurements among Asian children using hand radiographs and using this correlation as an aid in determining bone age. MATERIALS AND METHOD: In this analytic research, 304 hand radiographs from Asian children with normal development have been included in this study (155 female, 149 male). Two radiologists using Greulich and Pyle method assessed their bone ages. The 2nd-5th metacarpal bones length and width and 2nd-5th metacarpophalangeal joints width and length were manually measured by Adobe Photoshop and compared with subjects' skeletal age. Pearson correlation was used to determine the relationship. RESULTS: Pearson correlation between bone age and metacarpal bones length was 0.902-0.938; metacarpal bones width was 0.452-0.850; metacarpophalangeal joints width was 0.656 - 0.811, and metacarpophalangeal joints length was 0.920 - 0.947. CONCLUSION: Regarding Pearson correlation, metacarpophalangeal joints length, metacarpal bones length, metacarpophalangeal joints width, and metacarpal bones width showed significant relationship with bone age, respectively. These measurements can be used as accessory criteria for bone age assessment using left hand radiography, to reduce inter-observer reading differences.

The Dorsal 4-finger Technique: A Novel Method to Examine Metacarpophalangeal Joints in Patients with Rheumatoid Arthritis.

OBJECTIVE: To describe the dorsal 4-finger technique (DFFT) in examining metacarpophalangeal (MCP) joints of patients with rheumatoid arthritis (RA) and compare it to the traditional 2-finger technique (TFT) using ultrasound (US) as a gold standard. METHODS: Four rheumatologists evaluated 180 MCP joints of 18 patients with RA. All patients underwent US for greyscale (GSUS) and power Doppler US (PDUS). Agreements between rheumatologists, the 2 techniques, and US were evaluated using Cohen κ and the first-order agreement coefficient (AC1) κ methods. RESULTS: The population comprised 17 females (94.4%) with a mean (SD) age and disease duration of 56.8 (14.4) and 21.8 (12.9) years, respectively. Eight patients (44.4%) were taking methotrexate monotherapy, while 10 patients (55.6%) were receiving biologics. US evaluation revealed 69 (38.3%) and 30 (16.7%) joints exhibited synovitis grade 2-3 by GSUS and PDUS, respectively. Effusion was documented in 30 joints (16.7%). The mean intraobserver agreement using the DFFT and TFT were 80.5% and 86%, respectively. The mean interobserver agreements using the DFFT and TFT were 84% and 74%, respectively. κ agreement with US findings was similar for both techniques in tender joints but was higher for the DFFT in nontender joints (0.33 vs 0.07, p = 0.015 for GSUS) and (0.48 vs 0.11, p = 0.002 for PDUS). The DFFT had a higher sensitivity in detecting ballottement by GSUS (0.47 vs 0.2, p < 0.001) and PDUS (0.60 vs 0.27, p < 0.001). CONCLUSION: The DFFT is a novel, reproducible, and reliable method to examine MCP joints, and it has a better correlation with US than the traditional TFT.

Effect of the Inclusion of the Metacarpophalangeal Joints on the Wrist Magnetic Resonance Imaging Scoring System in Juvenile Idiopathic Arthritis.

OBJECTIVE: To extend the magnetic resonance imaging (MRI) score for assessment of wrist synovitis in juvenile idiopathic arthritis (JIA) by inclusion of the metacarpophalangeal (MCP) joints, and to compare the metric properties of the original and the extended score. METHODS: Wrist MRI of 70 patients with JIA were scored by 3 independent readers according to (1) the wrist component of the rheumatoid arthritis MRI synovitis score (comprising distal radioulnar, radiocarpal, and combined midcarpal and carpometacarpal joints); and (2) an extended score including the MCP joints. Thirty-eight patients had a 1-year MRI followup. The concordance between the readers [intraclass correlation coefficient (ICC), 95% limits of agreement (LOA), and weighted Cohen's κ], correlations with clinical variables (Spearman's ϱ), and the sensitivity to change [standardized response mean (SRM)] were calculated for both scores. RESULTS: The interreader agreement was moderate for the original score (ICC 0.77; 95% CI 0.68-0.84) and good for the extended score (ICC 0.86; 95% CI 0.80-0.91). Using 95% LOA, the aggregate score variability was less favorable with relatively wide LOA. Weighted Cohen's κ of the individual joints indicated good agreement for the original score and good to excellent agreement for the extended score. Correlations with clinical variables reflecting disease activity improved for the extended score and its SRM was higher compared to that of the original score. CONCLUSION: The extended score showed better reliability, construct validity, and sensitivity to change than the original. Inclusion of the MCP joints should be considered for a more accurate assessment of disease activity and treatment efficacy in JIA.

Sarcoidosis with prevalent and severe joint localization: a case report.

BACKGROUND: Sarcoidosis is a systemic granulomatous disease of unknown origin, characterized by the formation of granulomas without central necrosis. Each organ and tissue can be affected by the disease, but in most cases mainly the lungs and mediastinal lymph nodes but also skin, heart, eyes and joints are involved, the latter are mainly the metacarpophalangeal joints and bone lesions are often associated with involvement of the overlying skin. The diagnosis is often of exclusion, based on clinical and radiological suspicion, and should be confirmed by biopsy, although in each case it is necessary to exclude other possible causes of granulomatosis, including infections by mycobacteria. Here it is reported a case of particularly aggressive sarcoidosis with primitive involvement of the small joints of the hands and feet, and mediastinal lymph nodes. CASE PRESENTATION: The subject, a man, 60 years old, born in Morocco but living in Italy for many years, presented important involvement of bone structures and soft periarticular tissue, and was affected by the formation of granulomas without "caseum necrosis". The painful symptoms and the skin ulceration had led to surgical amputation of the distal phalanges of most fingers of his hands and feet, but with subsequent resurgence of lesions in acral locations after surgery. The PET/CT scan showed an amount of radiotracer in mediastinal lymph nodes, while the lymph nodes sampled by TBNA were normal and the CD4/CD8 ratio was less than 3 in the bronchoalveolar lavage. We ruled out any possible infectious cause, including mycobacterial infection (both tubercular and atypical), so the patient was treated with systemic corticosteroids, with an excellent clinical and radiological response. CONCLUSIONS: Such a case shows how the disease can have variable expressions, without primitive lung involvement; therefore, it should be necessary to consider any possible, unpredictable localization of the disease.

Ultrasound versus contrast-enhanced magnetic resonance imaging for subclinical synovitis and tenosynovitis: a diagnostic performance study

OBJECTIVES: Radiographic manifestations of synovitis (e.g., erosions) can be observed only in the late stage of rheumatoid arthritis. Ultrasound is a noninvasive, cheap, and widely available technique that enables the evaluation of inflammatory changes in the peripheral joint. In the same way, dynamic contrast-enhanced magnetic resonance imaging (MRI) enables qualitative and quantitative measurements. The objectives of the study were to compare the sensitivity and accuracy of ultrasound in detecting subclinical synovitis and tenosynovitis with those of contrast-enhanced MRI. METHODS: The ultrasonography and contrast-enhanced MRI findings of the wrist, metacarpophalangeal, and proximal interphalangeal joints (n=450) of 75 patients with a history of joint pain and morning stiffness between 6 weeks and 2 years were reviewed. The benefits score was evaluated for each modality. RESULTS: The ultrasonic findings showed inflammation in 346 (77%) joints, while contrast-enhanced MRI found signs of early rheumatoid arthritis in 372 (83%) joints. The sensitivities of ultrasound and contrast-enhanced MRI were 0.795 and 0.855, respectively, and the accuracies were 0.769 and 0.823, respectively. Contrast-enhanced MRI had a likelihood of 0-0.83 and ultrasound had a likelihood of 0-0.77 for detecting synovitis and tenosynovitis at one time. The two imaging modalities were equally competitive for detecting synovitis and tenosynovitis (p=0.055). CONCLUSION: Ultrasound could be as sensitive and specific as contrast-enhanced MRI for the diagnosis of subclinical synovitis and tenosynovitis.

Diseño y elaboración de una férula tipo tenodesis fabricada en termoplástico de alta resistencia policloruro de vinilo PVC para la promoción de agarre de pinza trípode en personas con secuelas de trauma raquimedular / Design and development of a kind tenodesis splint made in high resistance thermoplastic polyvinyl chloride PVC to promote tripod clamp grip in people with spinal cord trauma aftermath

El presente documento es una propuesta teórica, que tiene como finalidad presentar un protocolo de elaboración de una férula dinámica tipo tenodesis a partir de un material termoplástico de alta temperatura, de fácil consecución en el mercado llamado policloruro de vinilo; Este tipo de férula se clasifica dentro de las denominadas férulas dinámicas y su objetivo final es la promoción de agarre de pinza trípode en personas que por lesiones a nivel de C5-C6, presentan ausencia de movilidad en los dedos de la mano pero conservan movimientos de muñeca. Cuando el usuario extiende la muñeca, la férula activa una serie de mecanismos que producen flexión pasiva de articulaciones metacarpofalangicas de los dedos II y III y simultáneamente hay una abducción y una relativa oposición del pulgar; estos movimientos formarán una pinza que proveerá al usuario la posibilidad de realizar actividades básicas con sus manos.

This document is a methodological contribution, which is to present a protocol for developing a tenodesis type dynamic splint from a high temperature thermoplastic material, easy to achieve on the market called polyvinyl chloride, this type of splint is classified within the so-called dynamic splints and its purpose is to promote tripod pincer grip in people with injuries at C5-C6, present lack of mobility in the fingers but retain wrist movements. When the user extends the wrist, splint activates a series of mechanisms that produce passive flexion of metacarpophalangeal joints of fingers II and III and simultaneously there is a relative abduction and thumb opposition, these movements form a clamp that will provide the user the ability to perform basic activities with their hands.