Prevalence of amyloid deposition and cardiac amyloidosis in shoulder disease compared to carpal tunnel syndrome.

Background: Cardiac amyloidosis is a fatal disease of severe heart failure caused by the accumulation of amyloid in the myocardium. This disease is often advanced by the time cardiac symptoms appear; therefore, early detection and treatment are critical for a good prognosis. Recently, it has been suggested that cardiac amyloidosis is implicated in several orthopedic diseases, including carpal tunnel syndrome (CTS), which is often reported to precede cardiac dysfunction. Shoulder disease has also been suggested to be associated with cardiac amyloidosis; however, there have been no reports investigating the rate of amyloid deposition in shoulder specimens and the simultaneous prevalence of cardiac amyloidosis. Herein, we investigated the prevalence of intraoperative specimen amyloid deposition and cardiac amyloidosis in shoulder disease and CTS to determine the usefulness of shoulder specimen screening as a predictor of cardiac amyloidosis development. Methods: A total of 41 patients undergoing arthroscopic shoulder surgery and 33 patients undergoing CTS surgery were enrolled in this study. The shoulder group included rotator cuff tears, contracture of the shoulder, synovitis, and calcific tendonitis. In the shoulder group, a small sample of synovium and the long head of the biceps brachii tendon were harvested, while the transverse carpal ligament was harvested from the CTS group. The intraoperative specimens were pathologically examined for amyloid deposition, and patients with amyloid deposition were examined for the presence of cardiac amyloidosis by cardiac evaluation. Results: In the shoulder group, three cases (7.3%) of transthyretin amyloid deposition were found, all of which involved rotator cuff tears. None of these three cases with amyloid deposition were associated with cardiac amyloidosis. When examining the specimens, the amyloid deposition rate in the long head of the biceps brachii tendon was higher than that in the synovium. In the CTS group, 12 cases (36.4%) of transthyretin amyloid deposition were observed. Of these cases, seven underwent cardiac evaluation and two were identified with cardiac amyloidosis. Conclusion: While the prevalence of amyloid deposition and cardiac amyloidosis in the CTS group was consistent with previous reports, the shoulder group showed a lower deposition rate and no concomitant cardiac amyloidosis. Therefore, it remains debatable whether investigating amyloid deposition in samples obtained from shoulder surgery is beneficial for the early detection of cardiac amyloidosis.

Assessing ulnar neuropathy at the elbow using magnetoneurography.

OBJECTIVE: To measure neuromagnetic fields of ulnar neuropathy patients at the elbow after electrical stimulation and evaluate ulnar nerve function at the elbow with high spatial resolution. METHODS: A superconducting quantum interference device magnetometer system recorded neuromagnetic fields of the ulnar nerve at the elbow after electrical stimulation at the wrist in 16 limbs of 16 healthy volunteers and 21 limbs of 20 patients with ulnar neuropathy at the elbow. After artifact removal, neuromagnetic field signals were processed into current distributions, which were superimposed onto X-ray images for visualization. RESULTS: Based on the results in healthy volunteers, conduction velocity of 30 m/s or 50% attenuation in current amplitude was set as the reference value for conduction disturbance. Of the 21 patient limbs, 15 were measurable and lesion sites were detected, whereas 6 limbs were unmeasurable due to weak neuromagnetic field signals. Seven limbs were deemed normal by nerve conduction study, but 5 showed conduction disturbances on magnetoneurography. CONCLUSIONS: Measuring the magnetic field after nerve stimulation enabled visualization of neurophysiological activity in patients with ulnar neuropathy at the elbow and evaluation of conduction disturbances. SIGNIFICANCE: Magnetoneurography may be useful for assessing lesion sites in patients with ulnar neuropathy at the elbow.

Anatomical study of the bone morphology of the anterior talofibular ligament attachment.

Anterior talofibular ligament (ATFL) injuries are the most common cause of ankle sprains. To ensure anatomically accurate surgery and ultrasound imaging of the ATFL, anatomical knowledge of the bony landmarks around the ATFL attachment to the distal fibula is required. The purpose of the present study was to anatomically investigate the ATFL attachment to the fibula with respect to bone morphology and attachment structures. First, we analyzed 36 feet using microcomputed tomography. After excluding 9 feet for deformities, the remaining 27 feet were used for chemically debrided bone analysis and macroscopic and histological observations. Ten feet of living specimens were observed using ultrasonography. We found that a bony ridge was present at the boundary between the attachments of the ATFL and calcaneofibular ligament (CFL) to the fibula. These two attachments could be distinguished based on a difference in fiber orientation. Histologically, the ATFL was attached to the anterodistal part of the fibula via fibrocartilage anterior to the bony ridge indicating the border with the CFL attachment. Using ultrasonography in living specimens, the bony ridge and hyperechoic fibrillar pattern of the ATFL could be visualized. We established that the bony ridge corresponded to the posterior margin of the ATFL attachment itself. The ridge was obvious, and the superior fibers of the ATFL have directly attached anteriorly to it. This bony ridge could become a valuable and easy-to-use landmark for ultrasound imaging of the ATFL attachment if combined with the identification of the fibrillar pattern of the ATFL.

A screening method for cervical myelopathy using machine learning to analyze a drawing behavior.

Early detection of cervical myelopathy (CM) is important for a favorable outcome, as its prognosis is poor when left untreated. We developed a screening method for CM using machine learning-based analysis of the drawing behavior of 38 patients with CM and 66 healthy volunteers. Using a stylus pen, the participants traced three different shapes displayed on a tablet device. During the tasks, writing behaviors, such as the coordinates, velocity, and pressure of the stylus tip, along with the drawing time, were recorded. From these data, features related to the drawing pressure, and time to trace each shape and combination of shapes were used as training data for the support vector machine, a machine learning algorithm. To evaluate the accuracy, a receiver operating characteristic curve was generated, and the area under the curve (AUC) was calculated. Models with triangular waveforms tended to be the most accurate. The best triangular wave model identified patients with and without CM with 76% sensitivity and 76% specificity, yielding an AUC of 0.80. Our model was able to classify CM with high accuracy and could be applied to the development of disease screening systems useful outside the hospital setting.

Anteroinferior plating is an independent factor for decreasing symptomatic implant removal rates after plate fixation for midshaft clavicle fractures.

Objectives: The factors that significantly influence the symptomatic implant removal rates after plate fixation for midshaft clavicle fractures remain controversial. The purpose of this study was to compare the symptomatic implant removal rates between 2 different types of plating technique and to evaluate independently associated factors. Design: Retrospective cohort study. Setting: Acute care center. Patients/Participants: A total of 71 patients 16 years or older who were diagnosed with displaced midshaft clavicle fractures from April 2016 to March 2020. Intervention: Thirty-nine patients were treated with superior plating (Group SP), and the remaining 32 patients were treated with anteroinferior plating (Group AIP). Main Outcome Measurements: Symptomatic implant removal rates after plate fixation for midshaft clavicle fractures. Results: Symptomatic implant removal rates were significantly lower in Group AIP (28.1%) than in Group SP (53.8%) (P = 0.033). Multivariate analyses showed that symptomatic implant removal rates were significantly decreased by three independent factors, namely AIP (odds ratio [OR] = 0.323) (P = 0.037), greater age (45 years or older) (OR = 0.312) (P = 0.029), and high body mass index (≥25 kg/m2) (OR = 0.117) (P = 0.034). Conclusions: AIP significantly and independently decreased the symptomatic implant removal rate. Among the three explanatory factors showing significant difference, plating technique is the only factor that can be altered by medical institutions. Therefore, we recommend this technique for displaced midshaft clavicle fractures to reduce a second surgery such as symptomatic implant removal. Level of Evidence: Level 3, retrospective cohort study.

Radiation educational program significantly reduces intraoperative fluoroscopy time during locking plate fixation for distal radius fractures.

BACKGROUND: The use of C-arm fluoroscopy poses a risk of radiation exposure to the surgeons. This study aimed to examine the intraoperative fluoroscopy time of the distal radius plating before and after radiation educational program. METHODS: A total of 68 cases (48 women and 20 men; average age, 61.8 years) were reviewed between July 2017 and October 2019. All patients were treated with volar locking plate fixation for distal radius fractures. On October 2018, we had a 1-h radiation educational program for orthopedic surgeons. Intraoperative fluoroscopy time was compared between 34 cases in the preintervention group (group A) and 34 cases in the postintervention group (group B). Radiographic correction loss of the fracture was assessed by ulnar variance (UV), radial inclination (RI), and volar tilt (VT) between immediately after surgery and at the time of bone union. RESULTS: A significant difference was found in intraoperative fluoroscopy time between 329 s in group A and 123 s in group B. ΔUV between immediately after surgery and at the time of bone union was 0.6 mm in group A and 0.3 mm in group B; ΔRI was -0.3° in group A, -0.1° in group B, ΔVT is -0.4° in group A, and -0.1° in group B. No significant difference was found among them. CONCLUSIONS: After an educational program on radiation exposure, the intraoperative fluoroscopy time was significantly saved in the plating surgery for the distal radius fractures. The shortening of the intraoperative fluoroscopy time did not affect the loss of radiographic correction of the fractures.

Comparison of ceftriaxone and cefazolin as prophylactic antibiotics for surgical site infection in orthopedic upper extremity surgery: The nationwide shortage of cefazolin in March 2019.

BACKGROUND: Due to the nationwide supply shortage of cefazolin in March 2019 in Japan, ceftriaxone was used as an alternative prophylaxis antibiotic agent. This retrospective study was designed to investigate the impact of cefazolin and ceftriaxone as a prophylactic antibiotic agent for surgical site infection (SSI) in orthopedic upper extremity surgery. METHODS: We used cefazolin for antibiotic prophylaxis to prevent SSI before March 2019. Because of cefazolin shortage, ceftriaxone was used as an alternative agent in our hospital. From April 2014 to May 2021, 2493 upper extremity surgeries were reviewed. The exclusion criteria in this study were as follows: patients aged under 16 years, those with an open wound, those with infectious diseases, those who underwent trigger finger surgery, and those who underwent percutaneous pinning surgery. The incidence of deep SSI was evaluated according to the Centers for Disease Control and Prevention guidelines. RESULTS: Among the 2493 eligible cases, 1674 were included in this study. In the cefazolin group, 1140 cases were included, whereas, in the ceftriaxone group, 534 cases were included. No significant differences in the demographic data of the patients were observed between the two groups. The incidence of deep SSI was 0.08% (1/1140 cases) in the cefazolin group and 1.1% (6/534 cases) in the ceftriaxone group, with a significant difference between the two groups (odds ratio, 12.9; p = 0.005). CONCLUSIONS: This study indicated that the use of ceftriaxone instead of cefazolin after upper extremity surgery increases the risk of deep SSI.

High diagnostic accuracy of magnetic resonance imaging in detecting subscapularis tendon tears by focusing on the most superior portion of the subscapularis tendon.

PURPOSE: This study aimed to test the hypothesis that identifying the exact location of the most superior portion of the subscapularis tendon using magnetic resonance imaging (MRI) provides high diagnostic accuracy in detecting subscapularis tendon tears. METHODS: This study included 157 patients who underwent primary arthroscopic rotator cuff repair between 2014 and 2017. All patients underwent conventional 1.5-T MRI in our hospital, within 3 months before surgery. We retrospectively compared the diagnosis of subscapularis tendon tears using MRI based on an anatomical concept focusing on the superior-most insertion point of the subscapularis tendon with intraoperative arthroscopic findings. RESULTS: Subscapularis tendon tears were detected in 80 (51.0%) of the 157 patients during arthroscopic evaluation. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the MRI examination were 90, 83, 85, 89, and 87%, respectively. With a kappa score of 0.83, the concordance rate between the two raters was almost perfect (95% confidence interval, 0.75-0.92). The sensitivities of the oblique-sagittal and axial sequences were 84 and 79%, respectively. CONCLUSIONS: Preoperative MRI evaluation focusing on the most superior portion of the subscapularis tendon demonstrated high diagnostic accuracy in detecting subscapularis tendon tears. To find the most superior portion of the subscapularis tendon tears, it was essential to check the slice at the level of the lesser tubercle tip and its adjacent slice. In addition, the combined observation of oblique-sagittal and axial sequences helped to detect subscapularis tendon tears with higher sensitivity.

Medial patellofemoral ligament is a part of the vastus medialis obliquus and vastus intermedius aponeuroses attaching to the medial epicondyle.

PURPOSE: This study aimed to investigate the bony surface characteristic of the femoral attachment of the medial patellofemoral ligament (MPFL) and the correlation between the relevant layered structures, including muscular aponeurosis and the joint capsule, which contribute to patellofemoral joint (PFJ) stability. METHODS: The morphology of the medial aspect of the medial condyle using micro-computed tomography and analysed cortical bone thickening in 24 knees was observed. For the macroscopic and histological analyses, 21 and 3 knees were allocated, respectively. The Kruskal-Wallis one-way analysis of variance test with Dunn post hoc testing was performed for statistical analysis. RESULTS: At the level of the adductor tubercle, there were no significant differences in cortical bone thickness. At the level of the medial epicondyle (MEC), cortical bone thickness was considerably greater than that in other areas of the medial condyle (mean ± standard deviation, 0.60 ± 0.20 mm; p < 0.0001). Macroscopic analysis revealed that the deep aponeurosis of the vastus medialis obliquus and the tendinous arch of the vastus intermedius distally formed the composite membrane and adjoined to the joint capsule to firmly attach to MEC, which was located at 41.3 ± 5.7 mm posterior and 14.2 ± 3.1 mm superior to the joint cartilage. Histological analysis showed a composite membrane and adjoining capsule attached to MEC via fibrocartilage. CONCLUSION: MPFL could be interpreted as part of the deep aponeurosis of the vastus medialis obliquus (VMO) and the tendinous arch of the vastus intermedius, which combined with the joint capsule to attach to MEC. The cortical bone thickening indicated that the tensile stresses were loaded on MEC in aged cadavers. Involvement of VMO and vastus intermedius aponeuroses in restored graft of MPFL could utilise the dynamic stability of surrounding muscles to mimic a native structure.

Lateral Ulnar Collateral Ligament of the Elbow Joint: Reconsideration of Anatomy in Terms of Connection with Surrounding Fibrous Structures.

BACKGROUND: To improve the clinical results of lateral ulnar collateral ligament (LUCL) reconstruction of the elbow joint, better understanding of the anatomy of the aponeuroses and joint capsule could be relevant. This study considers the previously described anatomy of the LUCL in relation to the related aponeuroses and joint capsule rather than as a discrete ligament. We hypothesized that the deep aponeuroses of the superficial extensor muscles and supinator form a relevant portion of the joint capsule previously defined as the LUCL. METHODS: Twenty-four elbows (12 right) from 21 embalmed cadavers (age at the time of death, 54 to 99 years) were included in the study. Twenty elbows were studied macroscopically and 4, histologically. The joint capsule was detached from the bones, and local thickness was quantitatively analyzed using micro-computed tomography (micro-CT). RESULTS: The supinator aponeurosis and joint capsule intermingled to form a thick membrane (mean and standard deviation, 4.8 ± 1.2 mm), which we termed "the capsulo-aponeurotic membrane." It was thicker than the anterior (1.3 ± 0.4 mm) and posterior (2.5 ± 0.9 mm) parts of the capsule of the humeroradial joint (p < 0.001). The capsulo-aponeurotic membrane had a wide attachment on the distal part of the extensor digitorum communis and extensor digiti minimi (EDC/EDM) origin of the humerus, the lateral part of the coronoid process, and the posterior part of the radial notch of the ulna. The humeral attachment had a fibrocartilaginous structure. The deep aponeuroses of the EDC and extensor carpi ulnaris (ECU) were connected to the capsulo-aponeurotic membrane. CONCLUSIONS: The capsulo-aponeurotic membrane was composed of the supinator aponeurosis and joint capsule and was attached to the lateral epicondyle of the humerus, radial side of the coronoid process, and posterior part of the radial notch on the ulna. The entire structure appeared identical to the commonly defined lateral collateral ligament. The most posterior part was connected to the EDC and ECU aponeuroses, which is commonly labeled the LUCL but does not exist as a discrete ligament. CLINICAL RELEVANCE: Consideration of the accurate anatomy of the extensive attachment of the capsulo-aponeurotic membrane could provide useful clues for improvement in techniques of LUCL reconstruction and lateral epicondylitis pathology.

Assessment of Pain During Nerve Conduction Studies in Patients With Carpal Tunnel Syndrome.

Purpose: Patients with suspected carpal tunnel syndrome (CTS) often undergo nerve conduction studies (NCSs). Although patients sometimes complain of NCS-related discomfort, including severe pain, pain evaluations during such NCSs are lacking. We aimed to measure the pain experienced by patients with CTS during NCSs. Methods: This prospective study included 30 patients with CTS who underwent NCSs between April 2018 and March 2019. Pain because of electrical stimulation during NCSs was evaluated using a visual analog scale, and we statistically analyzed pain-related factors such as age, sex, complications, severity grading scale, the intensity of maximum stimulation, and examination time. Results: The mean visual analog scale score for NCSs was 5.2, and the visual analog scale score increased as the intensity of maximum stimulation and examination time increased. Conclusions: We measured the pain because of electrical stimulation experienced by patients with CTS during NCSs. Our findings indicate that medical staff must be mindful of the potential pain experienced by patients during NCSs and educate patients regarding the necessity of the examination and its procedures. Type of study/level of evidence: Diagnostic Ⅳ.

Assessing carpal tunnel syndrome with magnetoneurography.

OBJECTIVE: To measure the neuromagnetic fields of carpal tunnel syndrome patients after electrical digital nerve stimulation and evaluate median nerve function with high spatial resolution. METHODS: A superconducting quantum interference device magnetometer system was used to record neuromagnetic fields at the carpal tunnel after electrical stimulation of the middle digital nerve in 10 hands of nine patients with carpal tunnel syndrome. The patients were diagnosed based on symptoms (numbness, tingling, and pain) supported by a positive Phalen or Tinel sign. A novel technique was applied to remove stimulus-induced artifacts, and current distributions were calculated using a spatial filter algorithm and superimposed on X-ray. RESULTS: In 6 of the 10 hands, the amplitude of the inward current waveform attenuated to <70% or the nerve conduction velocity was <40 m/s. The results of conventional nerve conduction studies were normal for two of these six hands. All four hands that could not be diagnosed by magnetoneurography had severe carpal tunnel syndrome superimposed on peripheral neuropathy secondary to comorbidities. CONCLUSIONS: Technical improvements enabled magnetoneurography to noninvasively visualize the electrophysiological nerve activity in carpal tunnel syndrome patients. SIGNIFICANCE: Magnetoneurography may have the potential to contribute to the detailed diagnosis of various peripheral nerve disorders.

High-Dimensional Analysis of Finger Motion and Screening of Cervical Myelopathy With a Noncontact Sensor: Diagnostic Case-Control Study.

BACKGROUND: Cervical myelopathy (CM) causes several symptoms such as clumsiness of the hands and often requires surgery. Screening and early diagnosis of CM are important because some patients are unaware of their early symptoms and consult a surgeon only after their condition has become severe. The 10-second hand grip and release test is commonly used to check for the presence of CM. The test is simple but would be more useful for screening if it could objectively evaluate the changes in movement specific to CM. A previous study analyzed finger movements in the 10-second hand grip and release test using the Leap Motion, a noncontact sensor, and a system was developed that can diagnose CM with high sensitivity and specificity using machine learning. However, the previous study had limitations in that the system recorded few parameters and did not differentiate CM from other hand disorders. OBJECTIVE: This study aims to develop a system that can diagnose CM with higher sensitivity and specificity, and distinguish CM from carpal tunnel syndrome (CTS), a common hand disorder. We then validated the system with a modified Leap Motion that can record the joints of each finger. METHODS: In total, 31, 27, and 29 participants were recruited into the CM, CTS, and control groups, respectively. We developed a system using Leap Motion that recorded 229 parameters of finger movements while participants gripped and released their fingers as rapidly as possible. A support vector machine was used for machine learning to develop the binary classification model and calculated the sensitivity, specificity, and area under the curve (AUC). We developed two models, one to diagnose CM among the CM and control groups (CM/control model), and the other to diagnose CM among the CM and non-CM groups (CM/non-CM model). RESULTS: The CM/control model indexes were as follows: sensitivity 74.2%, specificity 89.7%, and AUC 0.82. The CM/non-CM model indexes were as follows: sensitivity 71%, specificity 72.87%, and AUC 0.74. CONCLUSIONS: We developed a screening system capable of diagnosing CM with higher sensitivity and specificity. This system can differentiate patients with CM from patients with CTS as well as healthy patients and has the potential to screen for CM in a variety of patients.

Comparison of the efficacy of the tension band wiring with eyelet wire versus anatomical locking plate fixation for the treatment of displaced olecranon fractures.

BACKGROUND: This retrospective study was conducted to assess the clinical outcome and complications between tension band wiring (TBW) with eyelet wire and locking plate fixation used for the treatment of displaced olecranon fractures. METHODS: A total of 58 patients (36 males and 22 females; mean age: 63 years) were reviewed between April 2014 and September 2020. TBW with Ring Pin (RP group) was applied in 24 patients, including 15 Mayo type ⅡA and 9 Mayo type ⅡB patients. Anatomical locking plate (ALP group) was used in 34 patients, including 22 Mayo type ⅡA and 12 Mayo type ⅡB patients. Clinical outcome was evaluated using the Mayo Elbow Performance Score (MEPS), and active range of motion of the elbow and forearm and postoperative complications were reviewed. RESULTS: General characteristic of the patients and the fracture type were similar in the two groups. The mean MEPS values were 96.5 ± 7.3 in the RP group and 94.9 ± 9.4 in the ALP group. The mean elbow flexion arc was 127°±11 in the RP group. The mean elbow flexion arc was 122°±18 in the ALP group. No significant differences in clinical outcomes were observed between the two groups. Complication rates were significantly higher in the ALP group (19/34: 56%) than in the RP group (6/24: 25%). CONCLUSION: Although there were no statistically significant differences in clinical outcomes between the two groups, the ALP group had a higher proportion of any complication than the RP group.

Anatomical Study of the Interosseous Ligament of the Tibiofibular Syndesmosis: An Analysis of Osseous Morphology and Attaching Interposing Structures.

BACKGROUND: The morphological features of the interosseous tibiofibular area in relation to the tensile stress of the interosseous ligament (IOL) have rarely been discussed. The purpose of the present study was to investigate the IOL on the basis of osseous surface morphology and macroscopic and histological anatomy. We hypothesized that the osseous surface of the interosseous tibiofibular area has a specific feature corresponding to the fibrous structure in the IOL. METHODS: Eighteen ankles from 15 cadavers were analyzed. Micro-computed tomography (micro-CT) images were obtained for all specimens to observe the osseous surface in the syndesmosis and to visualize the distribution of cortical bone thickness. Fifteen ankles were macroscopically analyzed, and the other 3 ankles were histologically analyzed. RESULTS: Micro-CT imaging revealed the osseous prominence on the medial side of the fibula. Cortical thickness mapping showed that the thickness of the cortical bone on the medial side of the fibula proximal to the prominence (mean and standard deviation, 1.4 ± 0.5 mm; p < 0.001) was greater in comparison with the other quadrants, namely, the proximal part of the tibia (0.8 ± 0.2), distal part of the fibula (0.7 ± 0.2), and distal part of the tibia (0.5 ± 0.1). Macroscopic analysis indicated that the perforating branch of the fibular artery ran through the proximal top of the IOL, which formed a thickened fiber and was attached to the fibular prominence. Histological analysis revealed that the thickened fibrous part of the IOL attached to the fibula via the fibrocartilaginous insertion. At the middle of the IOL, thin and fatty-like tissue was interposed between the tibia and the fibula. CONCLUSIONS: We observed that the osseous prominence of the fibula corresponded to the proximal thickened part of the IOL via the fibrocartilaginous attachment. The thickened proximal part of the IOL was consistently found in this location; we believe that this finding was related to the fact that the fibular artery perforated the adjacent distal part of the interosseous membrane (IOM). CLINICAL RELEVANCE: The location of the prominence on the medial aspect of the fibula could be a helpful clue as to the ideal location of syndesmotic fixation.

A Screening Method Using Anomaly Detection on a Smartphone for Patients With Carpal Tunnel Syndrome: Diagnostic Case-Control Study.

BACKGROUND: Carpal tunnel syndrome (CTS) is a medical condition caused by compression of the median nerve in the carpal tunnel due to aging or overuse of the hand. The symptoms include numbness of the fingers and atrophy of the thenar muscle. Thenar atrophy recovers slowly postoperatively; therefore, early diagnosis and surgery are important. While physical examinations and nerve conduction studies are used to diagnose CTS, problems with the diagnostic ability and equipment, respectively, exist. Despite research on a CTS-screening app that uses a tablet and machine learning, problems with the usage rate of tablets and data collection for machine learning remain. OBJECTIVE: To make data collection for machine learning easier and more available, we developed a screening app for CTS using a smartphone and an anomaly detection algorithm, aiming to examine our system as a useful screening tool for CTS. METHODS: In total, 36 participants were recruited, comprising 36 hands with CTS and 27 hands without CTS. Participants controlled the character in our app using their thumbs. We recorded the position of the thumbs and time; generated screening models that classified CTS and non-CTS using anomaly detection and an autoencoder; and calculated the sensitivity, specificity, and area under the curve (AUC). RESULTS: Participants with and without CTS were classified with 94% sensitivity, 67% specificity, and an AUC of 0.86. When dividing the data by direction, the model with data in the same direction as the thumb opposition had the highest AUC of 0.99, 92% sensitivity, and 100% specificity. CONCLUSIONS: Our app could reveal the difficulty of thumb opposition for patients with CTS and screen for CTS with high sensitivity and specificity. The app is highly accessible because of the use of smartphones and can be easily enhanced by anomaly detection.

Anatomic study of fibrous structures attached to the volar ulnar corner of the radius: implications in the volar rim fracture.

This study aimed to clarify the bone and soft tissue morphological features at the volar ulnar corner of the radius. Micro-computed tomography, macroscopic and histological analyses were conducted using 12 cadaveric wrists, and in vivo MRI studies of the wrist were evaluated in five healthy volunteers. The volar ulnar corner of the distal radius has a protrusion volar to the sigmoid notch. The capsule elements of the radiolunate and radioulnar joints merge and this conjoined capsule attaches to the radius at the ulnar protrusion. Histologically, this capsule attaches to the radius via fibrocartilage, with fibres running in the radioulnar direction. In-vivo MRI studies showed that the capsule attaching to the volar ulnar corner could be traced to the dorsal side of the ulnar styloid. Our findings indicate that, given the direction of the fibres, an avulsion force in the radioulnar direction could be a cause for volar rim fractures.

Prediction of Stress Distribution Applied to the Triangular Fibrocartilage Complex: A Finite Element Analysis.

Purpose: The triangular fibrocartilage complex (TFCC) is an important tissue stabilizer for the distal radioulnar joint, but stress distribution on the TFCC is not clear. The purpose of this study was to report the stress distribution of the TFCC using finite element analysis (FEA). Methods: Pathological specimens of the wrist joint from an 80-year-old man were imported into a finite element analysis software package, and regions of interest including bone, soft tissue, and TFCC were extracted to create a 3-dimensional model. The material properties were obtained from previous research using cadaver specimens. To allow large deformations, we used hyperelastic elements to model the TFCC and soft tissue. Bone was defined as a uniform tissue that did not break. With the carpals and radius constrained, the rotation axis was set at the center of the ulnar head and a force was applied to move the ulnar head in pronation and supination. Under these boundary conditions, the behavior of the TFCC was extracted as a moving image. The average value of the maximum principal stress for each component of the TFCC was extracted and graphed. Results: In the supinated position, the maximum principal stress was found on the palmar side of the TFCC (eg, on the tension side). In pronation, the maximum principal stress was found on the dorsal side. Conclusions: This study clearly showed the 3-dimensional structure of the TFCC and analyzed its stress distribution under load. In supination, mean values of the maximum principal stress were greater on the palmar fibers than the dorsal fibers. In pronation, mean maximum principal stress was greater on the dorsal fibers than the palmar fibers. Clinical relevance: Knowing the distribution of stresses in the TFCC is an important factor in developing treatment strategies for a pathologic TFCC.

Anatomy of inferior end of palatopharyngeus: its contribution to upper esophageal sphincter opening.

PURPOSE: The palatopharyngeus is one of the longitudinal pharyngeal muscles which contributes to swallowing. It is reported that the palatopharyngeus has muscle bundles in various directions and with attachment sites, and each muscle bundle has a specific function. Although previous reports suggest that the palatopharyngeus is partly interlaced with some parts of the inferior constrictor, the precise relationship remains unclear. The purpose of this study was to examine the precise manner of the connection between the palatopharyngeus and inferior constrictor, and to examine the histological characteristics of this connection. METHODS: We examined 15 halves of nine heads from Japanese cadavers (average age: 76.1 years); 12 halves, macroscopically, and three halves, histologically. RESULTS: Our observation suggests that the palatopharyngeus spreads radially on the inner aspect of the pharyngeal wall. The most inferior portion of the palatopharyngeus extended to the inner surface of the cricopharyngeal part of the inferior constrictor. Histological analysis showed that the inferior end of the palatopharyngeus continued into the dense connective tissue located at the level of the cricoid cartilage. The dense connective tissue not only covered the inner surface of the inferior constrictor but also entered its muscle bundles and enveloped them. CONCLUSION: Therefore, the palatopharyngeus interlaced the cricopharyngeal part of the inferior constrictor through the dense connective tissues. The findings of this study show that the palatopharyngeus may act on the upper esophageal sphincter directly and help in its opening with the aid of the pulling forces in the superolateral direction.