Diagnosis of Ulnar Neuropathy at the Elbow Using Ultrasound - A Comparison to Electrophysiologic Studies.

PURPOSE: Given the relatively high false negative rate of electrodiagnostic studies (EDX) in patients with clinically diagnosed ulnar neuropathy at the elbow (UNE), we sought to determine whether an alternative objective test could more effectively detect UNE. Additionally, we proposed to determine the relationship between the cross-sectional area (CSA) of the ulnar nerve on ultrasound (US), EDX, and clinical symptoms. METHODS: This was a retrospective study of patients presenting with symptomatic UNE. The performance characteristics of EDX versus ultrasound were calculated using the clinical diagnosis of UNE as the reference standard. Standard EDX studies and US of the ulnar nerve were analyzed. Maximal CSA of the ulnar nerve and EDX severity were analyzed for patients with each combination of US-positive/negative and EDX-positive/negative findings. RESULTS: Analysis was performed on 89 patients and 115 nerves with signs and symptoms of cubital tunnel syndrome. In total, 56 (49%) nerves were diagnosed as mild UNE, 32 (28%) nerves were diagnosed as moderate UNE, 17 (15%) nerves were diagnosed as severe UNE, and 10 (8%) nerves were negative for UNE by EDX. Maximal-maximal CSA was highly correlated with disease severity as determined by nerve conduction studies/electromyography. Compared with EDX+/US+, patients with EDX-/US+ showed higher rates of ulnar sensory loss and elbow tenderness with similar rates of positive Tinel and intrinsic muscle atrophy. In this sample of patients with clinically diagnosed UNE, 91.3% of the patients demonstrated positive EDX studies, whereas 94.8% had a positive US. CONCLUSIONS: Ultrasound is an alternative to EDX that could be incorporated clinically in the diagnosis and management of UNE. Ultrasound was able to consistently detect clinically positive cubital tunnel syndrome demonstrating its utility as a confirmatory or supplemental test to the clinical assessment if one is required. Ultrasound additionally may be able to better identify patients with early stages of UNE with negative EDX findings. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

CUBITAL TUNNEL SYNDROME DUE TO AN INTRANEURAL GANGLION CYST OF THE ULNAR NERVE.

Cubital tunnel syndrome is the second most common neuropathy of the upper extremity. Cubital tunnel syndrome caused by intraneural ganglion cysts is rare in clinical practice. We present the case of a 71-year-old male patient with a 4-month history of cubital tunnel syndrome of the left elbow due to an intraneural ganglion cyst. After revision of the ulnar nerve and resection of the intraneural cyst nearly complete recovery was achieved within a 5 month follow-up but some sensory deficits of the fifth fingertip. We recommend preoperative ultrasound examination of the cubital tunnel even in cases with clear diagnosis. Ganglion cyst as a cause of cubital tunnel is rare but needs to be diagnosed and treated as soon as possible to prevent irreversible complications.

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.

Dynamic analysis of the ulnar nerve and cubital tunnel morphology using ultrasonography: a cadaveric study.

BACKGROUND: The causes of ulnar neuropathy at the elbow are unclear. The authors hypothesized that the humeral trochlea protrudes into the cubital tunnel during elbow flexion and causes a dynamic morphologic change of the ulnar nerve in the cubital tunnel. METHODS: An ultrasonic probe was fixed to the ulnar shafts of 10 fresh cadavers with an external fixator, and dynamic morphology of the cubital tunnel and ulnar nerve was observed. The distance from the Osborne band to the trochlea (OTD), distance from ulnar nerve center to the trochlea (UTD), and the short- and long-axis diameters of the nerve at 30°, 60°, 90°, and 120° of elbow flexion were recorded. We compared the OTD, UTD, and the flattening of the ulnar nerve at the different angles of flexion using single-factor analysis of variance. Correlation between the ulnar nerve flattering, OTD, and UTD was examined using Spearman correlation coefficient. A P value less than .05 was used to denote statistical significance. RESULTS: Flattening of the ulnar nerve progressed with increasing elbow flexion and was significantly different between 0° and 60°, 90°, and 120° (P = .03 at 60°, P < .01 at 90° and 120°). OTD decreased with elbow flexion, and there was a significant difference at all elbow flexion angles (all P < .01). UTD decreased significantly from 0° flexion to 90° flexion (P = .03). Flattening of the nerve was significantly correlated with the OTD (r = 0.66, P < .01). CONCLUSIONS: A positive correlation was found between the protrusion of the humeral trochlea into the cubital tunnel during elbow flexion and ulnar nerve flattening using cadaveric elbow and ultrasonography.

Changes in Ultrasound Measurements of the Ulnar Nerve at Different Elbow Joint Positions in Patients with Cubital Tunnel Syndrome.

Ultrasound imaging (US) is increasingly being used in the diagnosis of entrapment neuropathies. The aim of the current study was to evaluate changes in stiffness (shear modulus), cross-sectional area (CSA), and trace length (TRACE) of the ulnar nerve in patients with cubital tunnel syndrome (CuTS), with shear wave elastography (SWE). A total of 31 patients with CuTS were included. CSA, shear modulus, and TRACE examinations were performed in the SWE mode in four positions of the elbow: full extension, 45° flexion, 90° flexion, and maximum flexion. There were significant side-to-side differences in the ulnar nerve elasticity value at 45°, 90°, and maximal elbow flexion (all, p < 0.001) but not at elbow extension (p = 0.36). There were significant side-to-side differences in the ulnar nerve CSA value at each elbow position (all, p < 0.001). There were significant side-to-side differences in the ulnar nerve trace value at each elbow position (all, p < 0.001). The symptomatic ulnar nerve in patients with CuTS exhibited greater stiffness (shear modulus), CSA, and TRACE values, compared with the asymptomatic side. US examinations (shear modulus, CSA, and TRACE evaluation) of the ulnar nerve can be helpful in supporting and supplementing the diagnosis in patients with CuTS.

Ultrasonographic Findings of the Ulnar Nerve Following Elbow Flexion in Patients with Cubital Tunnel Syndrome.

OBJECTIVE: To evaluate the ultrasonographic findings obtained following various degrees of elbow flexion in patients with cubital tunnel syndrome (CuTS). DESIGN: Retrospective, cross-sectional study. SETTING: General teaching hospital, rehabilitation unit. SUBJECTS: Electrophysiological and ultrasonographic assessments were performed on 11 elbows of healthy controls and 21 elbows of 17 patients with CuTS. METHODS: Dynamic movement of the ulnar nerve during elbow motion was measured. To measure ulnar nerve dynamic movement during elbow motion, the distance from the medial epicondyle (ME) to the nearest surface of the ulnar nerve toward the ME was measured at the cubital tunnel inlet at elbow extension (0°), elbow flexion to 60°, and elbow flexion to 90°. RESULTS: The distance between the ME and ulnar nerve was lower in CuTS patients than in healthy patients at all elbow flexion angles. This difference was statistically significant at 0° and 60° elbow flexion (P < 0.05). When calculating the cutoff value, the distance between the ME and ulnar nerve at full elbow extension for CuTS diagnosis was 0.53 cm (sensitivity = 71.4%, specificity = 90.7%). The distance ratio between the ME and ulnar nerve for diagnosis of ulnar neuropathy at the elbow was 24.4% (sensitivity = 76.2%, specificity = 100%). CONCLUSION: Measurement of the distance between the ME and ulnar nerve in full elbow extension may facilitate the diagnosis of patients with CuTS. These findings may be important for CuTS diagnosis, as they were also observed in patients with mild-stage CuTS.

Ultrasound-Guided Cubital Tunnel Decompression in a Collegiate Swimmer: A Case Report.

A 19-year-old female collegiate swimmer presented to our sports medicine clinic with a history and physical examination consistent with right ulnar neuropathy at the cubital tunnel. Diagnostic ultrasound (US) revealed compression of the ulnar nerve under the cubital tunnel retinaculum (CTR) with nerve swelling proximal to the site of compression. Electrodiagnostic studies confirmed the diagnosis of a moderate to severe ulnar neuropathy at the elbow. Treatment consisted of an US-guided decompression of the ulnar nerve in the cubital tunnel by cutting the CTR using a rotated stylet "v" cutting technique. The patient's symptoms resolved, and she was able to begin a swimming progression 2 weeks after the procedure. After completion of this progression, she was able to successfully resume full, unrestricted competitive collegiate swimming without return of her symptoms. To the best of our knowledge, this is the first description of an US-guided cubital tunnel decompression surgery.

Radiomics of peripheral nerves MRI in mild carpal and cubital tunnel syndrome.

OBJECTIVE: To assess the discriminative power of radiomics of peripheral nerves at 1.5T MRI, using common entrapment neuropathies of the upper limb as a model system of focal nerve injury. MATERIALS AND METHODS: Radiomics was retrospectively done on peripheral nerve fascicles on T1-weighted 1.5T MRI of 40 patients with diagnosis of mild carpal (n = 25) and cubital tunnel (n = 15) syndrome and of 200 controls. Z-score normalization and Mann-Whitney U test were used to compare features of normal and pathological peripheral nerves. Receiver operating characteristic analysis was performed. RESULTS: A total of n = 104 radiomics features were computed for each patient and control. Significant differences between normal and pathological median and ulnar nerves were found in n = 23/104 features (p < 0.001). According to features classification, n = 5/23 features were shape-based, n = 7/23 were first-order features, n = 11/23 features were classified as gray level run length matrix. Nine of the selected features showed an AUC higher that 0.7: minimum AUC of 0.74 (95% CI 0.61-0.89) for sum variance and maximum AUC of 0.90 (95% CI 0.82-0.99) for zone entropy. CONCLUSION: Features analysis demonstrated statistically significant differences between normal and pathological nerve. The results suggested that radiomics analysis could assess the median and ulnar nerve inner structure changes due to the loss of the fascicular pattern, intraneural edema, fibrosis or fascicular alterations in mild carpal tunnel and mild cubital tunnel syndromes even when the nerve cross-sectional area does not change.

Ultrasound Parameters Other Than the Direct Measurement of Ulnar Nerve Size for Diagnosing Cubital Tunnel Syndrome: A Systemic Review and Meta-analysis.

OBJECTIVE: To investigate the diagnostic performance of available ultrasound (US) parameters, other than the direct measurements of ulnar nerve size, that is, cross-sectional area (CSA) and diameter, for diagnosing cubital tunnel syndrome (CuTS). DATA SOURCES: Databases, including PubMed and Embase, were searched from the earliest record of CuTS US to April 24, 2018. STUDY SELECTION: Published studies (N=13) comparing US parameters of ulnar nerves between patients with CuTS and patients without CuTS were included. DATA EXTRACTION: Study design, participants' demographics, diagnostic references of CuTS, and US parameters other than the direct measurements of the ulnar nerve size were retrieved from the included studies. DATA SYNTHESIS: This systematic review comprised 663 CuTS patients and 543 patients without CuTS. The pooled nerve swelling ratio in the CuTS group was significantly larger than that of the controls. The mean between-group differences of CSAMax or ME/CSAarm, CSAMax or ME/CSAforearm and CSAMax or ME/CSAwrist were 1.03 (95% confidence interval [CI], 0.77-1.29), 1.38 (95% CI, 0.93-1.82), and 0.83 (95% CI, 0.56-1.11), respectively. Regarding the swelling ratio of CSAMax or ME /CSAarm, the pooled sensitivity and specificity available from the 3 included studies were 0.67 (95% CI, 0.59-0.74) and 0.81 (95% CI, 0.75-0.86), respectively. Similarly, for the swelling ratio of CSAMax or ME/CSAforearm, the pooled sensitivity and specificity were 0.62 (95% CI, 0.54-0.69) and 0.86 (95% CI, 0.81-0.90), respectively. Other US parameters identified in this review included nerve-flattening ratio (maximum diameter/minimum diameter), nerve-to-tunnel ratio (ulnar nerve CSA/cubital tunnel CSA), nerve echogenicity, and intraneural vascularity, all of which were reported in a minority of included articles. CONCLUSIONS: Despite the insufficient number of pertinent studies to prove its superiority to other US measurements, the ulnar nerve-swelling ratio can be a complementary tool for diagnosing CuTS. The presence of intraneural vascularity, increased flattening ratio, and enlarged intraneural hypoechoic fraction also seem to be potential US indicators for CuTS diagnosis, which need to be validated with more prospective studies.

MR imaging of the postsurgical cubital tunnel: an imaging review of the cubital tunnel, cubital tunnel syndrome, and associated surgical techniques.

Ulnar nerve compression at the elbow, specifically the cubital tunnel, is the second most common upper extremity compression neuropathy. Many patients presenting with compression symptoms will subsequently undergo surgical intervention. We review the open surgical treatment of cubital tunnel syndrome and review the expected postoperative imaging appearance of those treatments on magnetic resonance imaging (MR), including: simple or in situ decompression, medial epicondylectomy, and anterior transposition, including subcutaneous, intramuscular, and submuscular variants. We discuss the relevant anatomy of the presurgical cubital tunnel and common sites and causes of ulnar nerve compression at and about the cubital tunnel. The imaging appearance of the preoperative and postoperative ulnar nerve and postoperative complications are reviewed.

'Bony' cubital tunnel syndrome caused by heterotopic ossification.

We reported a rare case of cubital tunnel syndrome caused by heterotopic ossification after burns. The ulnar nerve was encircled by bony tunnel structure which cause nerve compression, resulting in ulnar nerve lesion. Our case sheds light on possible etiological association which may help clinical management.

Shear-wave elastography: a new potential method to diagnose ulnar neuropathy at the elbow.

OBJECTIVES: The primary aim of this study was to verify if shear-wave elastography (SWE) can be used to diagnose ulnar neuropathy at the elbow (UNE). The secondary objective was to compare the cross-sectional areas (CSA) of the ulnar nerve in the cubital tunnel and to determine a cut-off value for this parameter accurately identifying persons with UNE. METHODS: The study included 34 patients with UNE (mean age, 59.35 years) and 38 healthy controls (mean age, 57.42 years). Each participant was subjected to SWE of the ulnar nerve at three levels: in the cubital tunnel (CT) and at the distal arm (DA) and mid-arm (MA). The CSA of the ulnar nerve in the cubital tunnel was estimated by means of ultrasonographic imaging. RESULTS: Patients with UNE presented with significantly greater ulnar nerve stiffness in the cubital tunnel than the controls (mean, 96.38 kPa vs. 33.08 kPa, p < 0.001). Ulnar nerve stiffness of 61 kPa, CT to DA stiffness ratio equal 1.68, and CT to MA stiffness ratio of 1.75 provided 100% specificity, sensitivity, positive and negative predictive value in the detection of UNE. Mean CSA of the ulnar nerve in the cubital tunnel turned out to be significantly larger in patients with UNE than in healthy controls (p < 0.001). A weak positive correlation was found in the UNE group between the ulnar nerve CSA and stiffness (R = 0.31, p = 0.008). CONCLUSIONS: SWE seems to be a promising, reliable and simple quantitative adjunct test to support the diagnosis of UNE. KEY POINTS: • SWE enables reliable detection of cubital tunnel syndrome • Significant increase of entrapped ulnar nerve stiffness is observed in UNE • SWE is a perspective screening tool for early detection of compressive neuropathies.

Ulnar Nerve Cross-Sectional Area for the Diagnosis of Cubital Tunnel Syndrome: A Meta-Analysis of Ultrasonographic Measurements.

OBJECTIVE: To examine the performance of sonographic cross-sectional area (CSA) measurements in the diagnosis of cubital tunnel syndrome (CuTS). DATA SOURCES: Electronic databases, comprising PubMed and EMBASE, were searched for the pertinent literature before July 1, 2017. STUDY SELECTION: Fourteen trials comparing the ulnar nerve CSA measurements between participants with and without CuTS were included. DATA EXTRACTION: Study design, participants' demographic characteristics, diagnostic reference of CuTS, and methods of CSA measurement. DATA SYNTHESIS: Among different elbow levels, the between-group difference in CSA was the largest at the medial epicondyle (6.0mm2; 95% confidence interval [CI], 4.5-7.4mm2). The pooled mean CSA in participants without CuTS was 5.5mm2 (95% CI, 4.4-6.6mm2) at the arm level, 7.4mm2 (95% CI, 6.7-8.1mm2) at the cubital tunnel inlet, 6.6mm2 (95% CI, 5.9-7.2mm2) at the medial epicondyle, 7.3mm2 (95% CI, 5.6-9.0mm2) at the cubital tunnel outlet, and 5.5mm2 (95% CI, 4.7-6.3mm2) at the forearm level. The sensitivities, specificities, and diagnostic odds ratios pooled from 5 studies, using 10mm2 as the cutoff point, were .85 (95% CI, .78-.90), .91 (95% CI, .86-.94), and 53.96 (95% CI, 14.84-196.14), respectively. CONCLUSIONS: The ulnar nerve CSA measured by ultrasound imaging is useful for the diagnosis of CuTS and is most significantly different between patients and participants without CuTS at the medial epicondyle. Because the ulnar nerve CSA in healthy participants, at various locations, rarely exceeds 10mm2, this value can be considered as a cutoff point for diagnosing ulnar nerve entrapment at the elbow region.

Quantitative magnetic resonance imaging analysis of the cross-sectional areas of the anconeus epitrochlearis muscle, cubital tunnel, and ulnar nerve with the elbow in extension in patients with and without ulnar neuropathy.

BACKGROUND: The purpose of this study was to assess the cross-sectional area of the anconeus epitrochlearis muscle (AEM), cubital tunnel, and ulnar nerve with the elbow in extension in patients with and without ulnar neuropathy. METHODS: We performed a retrospective, level IV review of elbow magnetic resonance imaging (MRI) studies. Elbow MRI studies of 32 patients with an AEM (26 men and 6 women, aged 18-60 years), 32 randomly selected patients without an AEM (aged 16-71 years), and 32 patients with clinical ulnar neuritis (22 men and 10 women, aged 24-76 years) were reviewed. We evaluated the ulnar nerve cross-sectional area proximal to, within, and distal to the cubital tunnel; AEM cross-sectional area; and cubital tunnel cross-sectional area. RESULTS: We found no significant difference in the nerve caliber between patients with and without an AEM. No correlation was found between the AEM cross-sectional area and ulnar nerve cross-sectional area within the cubital tunnel (r = 0.14). The mean cubital tunnel cross-sectional area was larger in patients with an AEM. Only 4 of the 32 patients with an AEM had findings of ulnar neuritis on MRI. Of the 32 patients with a clinical diagnosis of ulnar neuritis, only 2 had an AEM. CONCLUSIONS: With the elbow in extension, the presence or cross-sectional area of an AEM does not correlate with the area of the ulnar nerve or cubital tunnel. Only a small number of individuals with MRI evidence of an AEM had clinical evidence of ulnar neuropathy. Likewise, MRI evidence of an AEM was found in only a small number of individuals with clinical evidence of ulnar neuropathy.

Use of High-Resolution Ultrasonography in Anterior Subcutaneous Transposition of the Ulnar Nerve for Cubital Tunnel Syndrome.

OBJECTIVES: Cubital tunnel syndrome (CTS) is the most common form of ulnar nerve entrapment. In this study, ultrasonography (US) was used not only for diagnosis but also for operation. US findings could be used to establish the diagnosis of CTS and could demonstrate the pathological anatomy in the cubital tunnel region to guide anterior subcutaneous transposition of the ulnar nerve. METHODS: Sixty-two patients with clinical and electrophysiological evidence of ulnar nerve entrapment were included. All patients received ultrasonographic examination and anterior subcutaneous transposition of the ulnar nerve. The maximal diameter of the ulnar nerve (MDU) was measured in longitudinal views and the range of the hypoechoic area around the nerve was observed. The cross-sectional area (CSA) was also measured on transverse scans. The actual MDU was measured during operation. RESULTS: The actual MDU was 6.4 ± 0.4 mm, measured during operation. The preoperative MDU was 3.1 ± 0.2 mm. The MDU values recorded in CTS patients were greater than those in normal subjects. The range of the hypoechoic area observed on longitudinal US scans was 2.9-5.6 mm (mean, 4.1 ± 0.4 mm). CONCLUSIONS: High-resolution US can be used not only in the diagnosis of CTS, also for providing effective preoperative evaluation for the anterior subcutaneous transposition of the ulnar nerve in CTS.

Cubital Tunnel Syndrome Caused by Ulnar Nerve Schwannoma in a Patient with Diabetic Sensorimotor Polyneuropathy.

PURPOSE: An uncommon ulnar nerve schwannoma should not be neglected in a diabetic patient with cubital tunnel syndrome, the second most common cause of entrapment neuropathy. CASE REPORT: A 61-year-old woman with a past history of type 2 diabetes mellitus complicated with sensorimotor polyneuropathy presented with progressive numbness and weakness of the left ring and little fingers for one year. A provisional diagnosis of cubital tunnel syndrome was made according to physical examination and electrophysiological studies. The magnetic resonance imaging showed a nodular lesion over ulnar aspect of the left elbow, which was demonstrated to be a schwannoma by histopathology. The patient had moderate improvement after surgical decompression of the left cubital tunnel. CONCLUSION: This case illustrates the heterogeneous group of pathologies causing peripheral neuropathy. The diagnosis of ulnar nerve schwannoma with cubital tunnel syndrome, superimposed with diabetic sensorimotor polyneuropathy, was made carefully according to clinical manifestations as well as a series of electrophysiological, imaging, and pathological studies.

Importance of the ultrasound in cubital tunnel syndrome.

We report a case of a patient with cubital tunnel syndrome caused by presence of a non-thrombotic vein in the cubital tunnel. Cubital tunnel syndrome is a symptom complex caused by the compression of the ulnar nerve at the elbow. It is the second most common peripheral compression neuropathy. Ulnar compression at the elbow can be clinically diagnosed; however, an electroneurographic examination is necessary to confirm the diagnosis. Sonography and MRI may be required to locate nerve lesions, but primarily to evaluate the causes of compression. We decided to report this case because it shows the importance of the ultrasound in the diagnosis of the cause of compressions, including those rare and unexpected.

Corticosteroid injection in patients with ulnar neuropathy at the elbow: A randomized, double-blind, placebo-controlled trial.

INTRODUCTION: We conducted a randomized, double-blind, placebo-controlled trial to evaluate the effect of ultrasound-guided corticosteroid injection in patients with ulnar neuropathy at the elbow (UNE). METHODS: Fifty-five patients were randomized between an ultrasound-guided injection of 1 ml containing 40 mg methylprednisolone acetate and 10 mg lidocaine hydrochloride or a placebo injection. The primary outcome was the subjective change of symptoms after 3 months. The secondary outcomes were change in electrodiagnostic studies and ultrasonography findings. RESULTS: A success rate of 30% was found in the corticosteroid injection group versus 28% in the placebo injection group. Only the nerve cross-sectional area changed significantly in the intervention group, from a mean of 11.9 mm(2) to 10.9 mm(2) . CONCLUSIONS: We could not demonstrate a positive effect of ultrasound-guided corticosteroid injection in UNE compared with placebo. Favorable outcomes may be attributed to the natural course of UNE or the effect of patient education.