Clinical Outcomes of Total Wrist Arthroplasty in Patients With Rheumatoid Arthritis: Minimum 10-Year Follow-Up Study.

PURPOSE: We developed a semiconstrained total wrist prosthesis that was used in a series of patients with rheumatoid arthritis. We previously reported favorable clinical outcomes for up to 5 years after surgery; however, the longer-term outcomes remain unclear. The objective of this study was to evaluate the clinical outcomes of this wrist prosthesis for the treatment of severe wrist rheumatoid arthritis during a minimum 10 years of follow-up. METHODS: From 2010 through 2012, total wrist arthroplasty using the semiconstrained total wrist arthroplasty device was performed in 20 wrists in 20 patients with rheumatoid arthritis (five men and 15 women). The mean patient age was 64 years (range, 50-84 years). Preoperative radiographs showed Larsen grade IV changes in 16 wrists and grade V changes in four wrists. Patients were evaluated clinically and radiologically before surgery, 5 years after surgery, and 10 years or more after surgery. Evaluated parameters were the visual analog scale for pain, range of motion, Figgie score, and Disabilities of the Arm, Shoulder, and Hand score. RESULTS: The minimum 10-year follow-up clinical results (mean, 11.3 years) were available for all 14 surviving patients (three men and 11 women). Significant improvements in the mean visual analog scale for pain, Figgie score, and Disabilities of the Arm, Shoulder, and Hand score, compared with those before surgery, were maintained from 5 years after surgery to the final follow-up. The mean wrist flexion angle tended to slightly decrease at 5 years after surgery compared with that before surgery but remained similar from 5 years after surgery to the final follow-up. The increase in the mean wrist extension angle, compared with that before surgery, was maintained from 5 years after surgery to the final follow-up. Radiographic evaluation had already revealed implant loosening in five of the 19 wrists at 5 years after surgery, but there were no new cases of component loosening identified at the final follow-up. CONCLUSIONS: Total wrist arthroplasty using the semiconstrained arthroplasty system achieves favorable clinical outcomes with no serious complications requiring revision for 10 years after surgery. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Unique skin findings in a case of the A3 pulley trigger finger due to an osteochondroma.

Trigger finger is usually caused by stenosing tenosynovitis and hypertrophy of the retinacular sheath, and the most common site of tendon triggering is the A1 pulley. Although the A3 pulley trigger finger has been described in a few cases caused by hypertrophy of the retinacular sheath and ganglion, associated skin findings have not been reported to date. Herein, we report a rare case of the A3 pulley trigger finger due to osteochondroma with unique skin findings in a 50-year-old woman. In this case, we observed a V-shaped skin depression on the palmar side of the proximal interphalangeal joint of the right middle finger during finger locking. Additionally, we observed bilateral linear skin depressions on the sides of the proximal phalange. These findings might be caused by the traction force on the A3 pulley, connected to the skin via the Grayson and Cleland ligaments, which are fibrous tissues that connect the skin and tendon sheath.

Initial patient demographics affecting return to original work after traumatic hand injury in a rural area in Japan: A retrospective single-center study.

BACKGROUND: Time off work after traumatic hand injury not only affects individuals but also has socioeconomic repercussions, becoming a serious problem from the viewpoint of labor shortages. In depopulated rural areas, the impact of labor shortages due to time off work is more serious than in urban areas; however, few studies have examined return to original work in rural areas. The purpose of this study was to investigate the patient demographics at the time of hand injury that affect return to original work in a rural area of Japan. METHODS: We retrospectively examined 246 patients with traumatic hand and/or forearm injuries who were working at the time of injury, and who underwent surgical operations and postoperative rehabilitation in a level II hospital in a rural agricultural area. We examined patients' initial demographic data, including gender, age, occupation (white or blue collar), employment status (self-employed, full-time, or part-time workers), complications other than hand injury, workers' compensation, dominant hand injury, and injury severity as determined using the modified Hand Injury Severity Score. Multivariate logistic regression analysis examined the association between initial patient demographics and return to original work within 150 days after injury. RESULTS: In total, 186 patients (76 %) were able to return to original work within 150 days. A multivariate logistic regression analysis showed that three explanatory variables (i.e., severity of injury, complications other than hand injury, and female gender) significantly compromised return to original work. CONCLUSIONS: In the treatment of traumatic hand injury, intensive support should be provided for return to original work for patients who are expected to have difficulty returning to work quickly. In addition, labor shortages can be mitigated by sharing information with the workplace about patients' prospects of return to original work.

Arthrodesis of the interphalangeal joints of the hand by two-dimensional intraosseous wiring.

BACKGROUND: Numerous techniques for arthrodesis have been described to fix interphalangeal (IP) joints, and the fixation method should be considered on a case-by-case basis. This study aimed to investigate the availability of IP joint arthrodesis of the hand, using a two-dimensional intraosseous wiring (two-DIOW) method. METHODS: A total of 43 joints (19 thumb IP joints, 9 proximal finger interphalangeal (PIP) joints and 15 distal interphalangeal (DIP) joints in 29 patients with a mean age of 66 years (range, 24-85 y) were retrospectively analyzed. All operations were performed with two-DIOW method. We evaluated the bone union rate, correction loss, presence of any surgical complications, and oral steroid use in cases of joint fixation using the two-DIOW method. RESULTS: Of these 43 digits, 42 achieved bone union (97.7%). Non-union was seen in a thumb IP joint of mutilans rheumatoid arthritis. Mean correction loss of deviation was 1.0°, and flexion or extension angulation was 1.6° in the direction of extension. Surgical complications included mild nail deformity in 2 digits and wire irritation necessitating wire removal in 2 digits. Oral steroids were used for 18 of the 43 digits, including 2 digits complicated by nail deformities. There was no infection and skin necrosis in all digits with or without steroid use. CONCLUSIONS: The two-DIOW method appears to offer an effective method of IP joint fixation, but caution should be exercised in digits of severe joint destruction and in the treatment of wire knot.

Median neuropathy after multiple punctures of the forearm for catheterization: A case report.

BACKGROUND: Neuropathy may occur at some sites after catheterization for close examination of cardiac disease. Although the radial artery is considered a relatively uncom-plicated site for catheterization, the radial artery and median nerve are in relatively close proximity, with the risk of median nerve injury depending on the angle of puncture. The purpose of this study was to report the outcomes of surgery performed for conservative therapy-resistant median neuropathy following forearm catheterization. CASE SUMMARY: A 50-year-old woman experienced palsy from the right thumb to the radial side of the ring finger after catheterization from the radial artery of the right forearm. Paresthesia developed at the same site and a positive tinel-like sign was seen for the median nerve area at the high level of the puncture site. Nerve conduction study showed reduced compound muscle action potentials and loss of sensory nerve action potentials. Symptoms did not improve despite pharmacotherapy and the patient gradually developed flexion restrictions of the index and middle fingers. Median nerve injury and associated flexor tendon adhesion was diagnosed, and the patient was referred for surgery at 3 mo after injury. When the same area was opened, no injury to the median nerve epithelium was obvious, but the area of the positive tinel-like sign was highly adherent to surrounding tissue and to the flexor digitorum superficialis of the index and middle fingers. The surgery was terminated with adequate adhesion release. Rehabilitation was initiated postoperatively, improving neurological symptoms and range of motion of the fingers. Six months after surgery, the patient returned to daily activities without discomfort. CONCLUSION: This case provides the appropriate diagnosis and treatment for a suspected peripheral nerve injury.

Deep fibrous histiocytoma of the index finger: a case report.

Our patient presented with an elastic soft mass of his left index finger. Hematoxylin and eosin staining showed a high cellular density with spindle-shaped cells in a storiform pattern. Immunohistochemical staining was positive for CD68, factor XIIIa and α-smooth muscle actin, and negative for CD34, STAT6, S100 protein, and desmin.

Growth rate-associated transcriptome reorganization in response to genomic, environmental, and evolutionary interruptions.

The genomic, environmental, and evolutionary interruptions caused the changes in bacterial growth, which were stringently associated with changes in gene expression. The growth and gene expression changes remained unclear in response to these interruptions that occurred combinative. As a pilot study, whether and how bacterial growth was affected by the individual and dual interruptions of genome reduction, environmental stress, and adaptive evolution were investigated. Growth assay showed that the presence of the environmental stressors, i.e., threonine and chloramphenicol, significantly decreased the growth rate of the wild-type Escherichia coli, whereas not that of the reduced genome. It indicated a canceling effect in bacterial growth due to the dual interruption of the genomic and environmental changes. Experimental evolution of the reduced genome released the canceling effect by improving growth fitness. Intriguingly, the transcriptome architecture maintained a homeostatic chromosomal periodicity regardless of the genomic, environmental, and evolutionary interruptions. Negative epistasis in transcriptome reorganization was commonly observed in response to the dual interruptions, which might contribute to the canceling effect. It was supported by the changes in the numbers of differentially expressed genes (DEGs) and the enriched regulons and functions. Gene network analysis newly constructed 11 gene modules, one out of which was correlated to the growth rate. Enrichment of DEGs in these modules successfully categorized them into three types, i.e., conserved, responsive, and epistatic. Taken together, homeostasis in transcriptome architecture was essential to being alive, and it might be attributed to the negative epistasis in transcriptome reorganization and the functional differentiation in gene modules. The present study directly connected bacterial growth fitness with transcriptome reorganization and provided a global view of how microorganisms responded to genomic, environmental, and evolutionary interruptions for survival from wild nature.

Radiolunate Arthrodesis in the Rheumatoid Wrist: A Retrospective Clinical and Radiologic Long-Term Follow-up.

PURPOSE: This study aimed to determine the results of radiolunate arthrodesis for rheumatoid arthritis (RA) after a long-term follow-up period of up to 20 years under tight postoperative medical control of RA. We also compared the results between patients with and without degenerative changes in the midcarpal joints at follow-up. We determined the radiologic factors predictive of secondary degenerative changes in the midcarpal joint. METHODS: This was a long-term retrospective analysis of 16 wrists of 14 patients with RA treated with radiolunate arthrodesis first reported in 2013. The mean follow-up period was 14 years (range, 8-23 years; SD, 4.6 years). Ten wrists had a Larsen classification of grade III, whereas 6 wrists had grade IV. The range of motion was assessed, and clinical outcomes were graded using the Mayo Wrist Score and Stanley classification system. The Carpal Height Index, Ulnar Translation Index, and changes in the midcarpal joint contour were determined from radiographs. We categorized the changes in the midcarpal joint as unchanged or degenerative. RESULTS: At final follow-up, the clinical scores improved; however, the extension and flexion range of motion was significantly reduced compared with that before surgery. The Carpal Height Index and Ulnar Translation Index improved immediately after surgery and remained stable at final follow-up. The changes in the midcarpal joint were categorized as unchanged in 6 wrists and degenerative in 10 wrists. The clinical outcomes were similar between the groups. The mean preoperative Ulnar Translation Index was significantly higher in the degenerative group than in the unchanged group. CONCLUSIONS: Radiolunate arthrodesis in patients with RA maintained good clinical results and corrected alignment, even during long-term follow-up. Preoperative severe ulnar translation deformity was a risk factor for postoperative degeneration of the midcarpal joint, and pre-existing degenerative changes at the midcarpal joint might lead to loss of wrist range of motion. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Dupuytren's contracture-associated SNPs increase SFRP4 expression in non-immune cells including fibroblasts to enhance inflammation development.

Dupuytren's contracture (DC) is an inflammatory fibrosis characterized by fibroproliferative disorders of the palmar aponeurosis, for which there is no effective treatment. Although several genome-wide association studies have identified risk alleles associated with DC, the functional linkage between these alleles and the pathogenesis remains elusive. We here focused on two single nucleotide polymorphisms (SNPs) associated with DC, rs16879765 and rs17171229, in secreted frizzled related protein 4 (SFRP4). We investigated the association of SRFP4 with the IL-6 amplifier, which amplifies the production of IL-6, growth factors and chemokines in non-immune cells and aggravates inflammatory diseases via NF-κB enhancement. Knockdown of SFRP4 suppressed activation of the IL-6 amplifier in vitro and in vivo, whereas the overexpression of SFRP4 induced the activation of NF-κB-mediated transcription activity. Mechanistically, SFRP4 induced NF-κB activation by directly binding to molecules of the ubiquitination SFC complex, such as IkBα and ßTrCP, followed by IkBα degradation. Furthermore, SFRP4 expression was significantly increased in fibroblasts derived from DC patients bearing the risk alleles. Consistently, fibroblasts with the risk alleles enhanced activation of the IL-6 amplifier. These findings indicate that the IL-6 amplifier is involved in the pathogenesis of DC, particularly in patients harboring the SFRP4 risk alleles. Therefore, SFRP4 is a potential therapeutic target for various inflammatory diseases and disorders, including DC.

Questionnaire survey about the effects of new lifestyles during the pandemic of COVID-19 on upper limb diseases.

BACKGROUND: The novel coronavirus (COVID-19) that emerged in 2019 and spread globally in 2020 has resulted in the imposition of lockdowns or a state of emergency in many cities worldwide. In Japan, a "new lifestyle" is being advocated. We hypothesize that the new lifestyle has changed people's use of their upper limbs during the COVID-19 pandemic. Therefore, through this questionnaire study, we aimed to determine the factors associated with exacerbation of symptoms during the pandemic and to investigate the current status of patients who require hand surgery. METHODS: This study was a prospective multi-center questionnaire survey. This study was conducted in Japan from December 2020 to July 2021 at university and general hospitals in nine prefectures. A questionnaire was administered to patients who visited a hospital with symptoms of nerve entrapment syndrome, osteoarthritis, or tenosynovitis. RESULTS: A total of 502 patients with a mean age of 63.8 years responded. The 240 patients who experienced exacerbation (exacerbated and markedly exacerbated) were compared with other patients (unchanged, improved, and markedly improved). An increase in the time spent on personal computers and smartphones was associated with exacerbation of hand symptoms. Patients who wanted to undergo surgery but were postponed due to COVID-19 accounted for 23.5% of the outpatients. The mean scores for pain, jitteriness, and anxious depression in these patients were significantly higher than those of patients who did not want surgery. CONCLUSIONS: Our results suggest that an increase in the time spent on personal computers and smartphones is associated with exacerbation of hand symptoms during the COVID-19 pandemic. Patients who wanted to undergo surgery but were postponed by COVID-19 experienced greater pain, jitteriness, and anxious depression.

Global coordination of the mutation and growth rates across the genetic and nutritional variety in Escherichia coli.

Fitness and mutability are the primary traits of living organisms for adaptation and evolution. However, their quantitative linkage remained largely deficient. Whether there is any general relationship between the two features and how genetic and environmental variables influence them remained unclear and were addressed here. The mutation and growth rates of an assortment of Escherichia coli strain collections, including the wild-type strains and the genetically disturbed strains of either reduced genomes or deletion of the genes involved in the DNA replication fidelity, were evaluated in various media. The contribution of media to the mutation and growth rates was differentiated depending on the types of genetic disturbance. Nevertheless, the negative correlation between the mutation and growth rates was observed across the genotypes and was common in all media. It indicated the comprehensive association of the correlated mutation and growth rates with the genetic and medium variation. Multiple linear regression and support vector machine successfully predicted the mutation and growth rates and the categories of genotypes and media, respectively. Taken together, the study provided a quantitative dataset linking the mutation and growth rates, genotype, and medium and presented a simple and successful example of predicting bacterial growth and mutability by data-driven approaches.

Correlation between carpal rotational alignment and postoperative wrist range of motion following total wrist arthroplasty.

BACKGROUND: Although total wrist arthroplasty (TWA) has become a common treatment option for wrists with damage due to rheumatoid arthritis (RA), the optimal implant axial alignment for TWA has been inadequately studied. This study was performed to investigate the relationships between implant alignment and carpal rotational alignment and the wrist range of motion (ROM) following TWA. METHODS: This study included 18 patients who underwent TWA using a DARTS® Total Wrist System (Teijin Nakashima Medical, Okayama, Japan) for wrist RA. Pre- and 6-month postoperative computed tomography scans were performed, including the radial volar line (Rv), capitohamate axis (CH), and Rv-CH angle in axial scans. The wrist ROM was also measured. The relationship between the Rv-CH angle and ROM was examined. RESULTS: The mean Rv-CH angle showed significant wrist pronation from 73.0° to 83.4° postoperatively. We observed a significant positive correlation (0.58) between the postoperative Rv-CH angle and extension and a significant negative correlation (- 0.56) between the postoperative Rv-CH angle and flexion. CONCLUSIONS: Implantation of the DARTS® TWA prosthesis resulted in pronation of the carpal axial alignment, which was correlated with postoperative wrist extension. The volar cortex of the distal radius can be a novel reference axis for adequate implant placement.

Influence of differences in bone morphology on the distribution patterns of subchondral bone density across the trapeziometacarpal joint.

We aimed to clarify the effects of morphological patterns of the trapezium and first metacarpal on the distribution of subchondral bone density across the articular surface of the trapeziometacarpal (TMC) joint using computed tomography osteoabsorptiometry. Thirty-three patients with normal TMC joints were evaluated. The percentages of the high-density areas in the radial-dorsal and ulnar-volar regions of the trapezium were significantly higher than that in the ulnar-dorsal region, and that of the ulnar-dorsal region of the first metacarpal was significantly lower than in the other three regions. The percentage of the high-density area of the radial-dorsal region of the trapezium and trapezial inclination (TI) showed a significant positive correlation, and the percentages of the high-density areas in the ulnar-dorsal and ulnar-volar regions had significant negative correlations with TI at the articular surface of the first metacarpal. These results indicate that bony morphologic differences in the trapezium affect the distribution pattern of subchondral bone density through the TMC joint.

Case Report: Hereditary Fibrosing Poikiloderma With Tendon Contractures, Myopathy, and Pulmonary Fibrosis (POIKTMP) Presenting With Liver Cirrhosis and Steroid-Responsive Interstitial Pneumonia.

Background: Hereditary fibrosing poikiloderma with tendon contractures, myopathy, and pulmonary fibrosis (POIKTMP) is an extremely rare disease caused by mutations in FAM111B, and only approximately 30 cases have been reported worldwide. Some patients develop interstitial pneumonia, which may lead to progressive pulmonary fibrosis and poor prognosis. However, no effective treatment for interstitial pneumonia associated with POIKTMP has been reported. Here, we report an autopsy case of POIKTMP, wherein interstitial pneumonia was improved by corticosteroids. Case Presentation: A 44-year-old Japanese man was referred to our hospital due to poikiloderma, hypotrichosis, and interstitial pneumonia. He developed progressive poikiloderma and muscle weakness since infancy. He also had tendon contractures, short stature, liver cirrhosis, and interstitial pneumonia. Mutation analysis of FAM111B revealed a novel and de novo heterozygous missense mutation, c.1886T > G (p(Phe629Cys)), through which we were able to diagnose the patient with POIKTMP. 3 years after the POIKTMP diagnosis, interstitial pneumonia had worsened. After 2 weeks of administrating 40 mg/day of prednisolone, his symptoms and lung shadows improved. However, he subsequently developed severe hepatic encephalopathy and eventually died of respiratory failure due to bacterial pneumonia and pulmonary edema. Autopsy revealed an unclassifiable pattern of interstitial pneumonia, as well as the presence of fibrosis and fatty degeneration in several organs, including the liver, kidney, skeletal muscle, heart, pancreas, and thyroid. Conclusions: We report a case of POIKTMP in which interstitial pneumonia was improved by corticosteroids, suggesting that corticosteroids could be an option for the treatment of interstitial pneumonia associated with this disease.

Minimum 5-Year Outcomes of Dorsal Intercarpal Ligament Capsulodesis With Scapholunate Interosseous Ligament Repair for Subacute and Chronic Static Scapholunate Instability: A Clinical Series of 5 Patients.

Purpose: Treatment of subacute and chronic static scapholunate instability remains challenging. We aimed to determine 5- to 10-year outcomes of dorsal intercarpal ligament capsulodesis with scapholunate interosseous ligament repair for subacute and chronic static scapholunate instability. Methods: Six patients with subacute and chronic static scapholunate instability underwent dorsal intercarpal ligament capsulodesis with scapholunate interosseous ligament repair between 2011 and 2015, and 5 of them were followed for at least 5 years after surgery. The clinical and radiological results were retrospectively investigated. All patients were male, and the mean age at surgery was 37 years (range, 21-47 years). The mean period from injury to surgery was 26.2 months (range, 2-113 months). The surgical procedure was a modification of a method reported by Szabo et al. Results: The mean postoperative follow-up period was 8.1 years (range, 5.1-9.5 years). Median Disabilities of the Arm, Shoulder, and Hand and Mayo wrist scores improved from 23.3 to 1.7 and from 55 to 80, respectively, from before surgery to the final follow-up. Although the median flexion angle tended to be smaller, the median extension angle tended to be greater than before surgery. The median percent grip strength increased from 72.3% before surgery to 99.2% at the final follow-up. The median scapholunate gap improved from 4.2 mm before surgery to 2.1 mm at the final follow-up. The median scapholunate angle also improved from 95.7° before surgery to 71.3° at the final follow-up. Osteoarthritic changes were observed in 2 of 5 patients at the final follow-up. Conclusions: The scapholunate gap in all patients was within the normal range after a mean of 8.1 years of follow-up. Dorsal intercarpal ligament capsulodesis with scapholunate interosseous ligament repair is considered a good alternative for subacute and chronic static scapholunate instability based on these 5- to 10-year outcomes. Type of study/level of evidence: Therapeutic IV.

Diagnostic Utility of Superb Microvascular Imaging and Power Doppler Ultrasonography for Visualizing Enriched Microvascular Flow in Patients With Carpal Tunnel Syndrome.

Recent studies suggest that blood flow changes in the median nerve may help confirm a diagnosis of carpal tunnel syndrome (CTS). Herein, we examined the utility of superb microvascular imaging (SMI), a new ultrasonographic (US) technique for visualizing microvascular flow, for detecting blood flow differences between CTS patients and healthy controls. We performed a retrospective analysis of 28 hands with suspected CTS. Patients received both nerve conduction and US examinations. Ten healthy volunteers were enrolled as the control group. The nerve compression ratio and the blood flow signal area were quantified using color Doppler US (CDUS), power Doppler US (PDUS), and SMI. Correlation analyses between the blood flow signal area, the compound muscle action potential of the thenar muscle, and the nerve compression ratio were performed. As a result, the mean nerve compression ratio was found to be significantly higher in the CTS group. There were no differences in the blood flow signal area between the groups using CDUS, while PDUS and SMI showed higher blood flow signals in the CTS group. The blood flow signal area measured by SMI had stronger correlations with the compound muscle action potential amplitude and the nerve compression ratio than those for PDUS. The diagnostic utility of SMI was equivalent to PDUS, but superior to conventional CDUS. Nevertheless, the blood flow signal by SMI was more strongly correlated with the electrophysiological severity and compression ratio than for PDUS. Use of SMI in future studies may help clarify the underlying mechanisms of blood flow changes in CTS.

Changes in wrist joint contact area following radial shortening osteotomy for Kienböck's disease.

We hypothesized that the contact area of the articular surface of the wrist joint could be evaluated using a custom-designed analytical program. The aim of the study was to compare the articular contact area of the wrist joint before and after radial shortening osteotomy for Kienböck's disease. Nine wrists of 9 patients underwent radial shortening osteotomy for Kienböck's disease. Computed tomography (CT) images of the wrist joint were reconstructed using a 3D reconstruction software package. Radioscaphoid and radiolunate joint contact areas and translation of the joint contact area from preoperative to postoperative were calculated using customized software. The mean Modified Mayo Wrist Score was significantly improved from 50.6 preoperatively to 83.3 at final follow-up (p < .001). Preoperatively, the pain was reported as severe in five wrists and moderate in four wrists, while at final follow-up, five patients were free from pain and four patients had mild pain with vigorous activity. The preoperative radioscaphoid joint contact area was 133.4 ± 49.5 mm2 and the postoperative radioscaphoid joint contact area was 156.4 ± 73.1 mm2. The preoperative radiolunate joint contact area was 194.8 ± 92.1 mm2 and the postoperative radiolunate joint contact area was 148.3 ± 97.9 mm2. The radial translation distance was 0.4 ± 1.2 mm, the dorsal translation distance was 0.6 ± 1.2 mm, and the proximal translation distance was 0.2 ± 0.4 mm. CT-based analysis revealed that the center of the contact area translated radially following radial shortening.

Dynamic Evaluation of Intraneural Microvascularity of the Ulnar Nerve Using Contrast-Enhanced Ultrasonography in Patients With Cubital Tunnel Syndrome.

PURPOSE: The purpose of this study was to compare the intraneural microvascular patterns of the ulnar nerve at 2 elbow flexion angles in asymptomatic volunteers and patients with cubital tunnel syndrome (CuTS) and to evaluate the effects of surgery on the microvascular pattern in patients with CuTS by using contrast-enhanced ultrasonography (CEUS). METHODS: This study included 10 elbows in 10 asymptomatic volunteers (control group) and 10 elbows in 10 patients with CuTS who underwent anterior subcutaneous transposition of the ulnar nerve (CuTS group). The CuTS group underwent clinical and electrophysiologic examinations and CEUS before surgery and at 1, 2, and 3 months after surgery. The intraneural enhancement pattern was calculated as an area under the curve (AUC) value in the entrapment site of the ulnar nerve within the cubital tunnel and in the area 1 cm proximal to the site (proximal site) at elbow flexion angles of 20° and 110°. RESULTS: Serial electrophysiologic examinations showed improvements at 1, 2, and 3 months after surgery compared with before surgery. In the control group, the AUC values of the central part of the cubital tunnel and proximal sites showed no substantial changes with the increase in elbow flexion. In the CuTS group, the AUC in the proximal site at 110° of elbow flexion was decreased compared with that at 20° of flexion before surgery. The AUC values for both the entrapment and proximal sites at 20° and 110° of elbow flexion were the most increased at 2 months after surgery compared with before surgery. CONCLUSIONS: Increased elbow flexion in patients with CuTS influences the intraneural blood flow of the ulnar nerve. Surgery for CuTS alters the intraneural blood flow. CLINICAL RELEVANCE: Quantitative evaluation of the intraneural blood flow of the ulnar nerve using CEUS may be a new supplementary diagnostic tool for CuTS and an indicator for the evaluation of postoperative recovery from nerve damage.