Performance of Sonoelastography for predicting malignancy in soft tissue.

BACKGROUND: Separating benign from malignant soft-tissue masses often requires a biopsy. The objective of this study was to assess whether shear-wave elastography (SWE) helped to separate benign from malignant soft-tissue masses. METHODS: In 2015-2016, we prospectively included patients with soft-tissue masses deemed by our multidisciplinary sarcoma board to require a diagnostic biopsy. All patients underwent ultrasonography (US) followed by SWE to measure elasticity. We compared benign and malignant tumors, overall and after separating tumors with vs. without a fatty component. The biopsy findings, and surgical-specimen histology when available, served as the reference standard. RESULTS: We included 136 patients, 99 with non-fatty and 37 with fatty soft-tissue masses. Mean elasticity and tumor-to-fat elasticity ratio (T/F) values were significantly lower for the benign than the malignant soft-tissue masses in the overall cohort (30.9 vs. 50.0 kilopascals (kPa), P = 0.03; and 2.55 vs. 4.30, P = 0.046) and in the non-fatty subgroup (37.8 ± 31.9 vs. 58.9 ± 39.1 kPa, P = 0.049 and 2.89 ± 5.25 vs. 5.07 ± 5.41, P = 0.046). Data for fatty tumors were non relevant due to lack of conclusive results. By receiver operating characteristics curve analysis, a T/F cutoff of 3.5 had 46% sensitivity and 84% specificity for separating benign and malignant soft-tissue masses. CONCLUSIONS: SWE had good specificity and poor sensitivity for separating benign from malignant soft-tissue masses.

Usefulness of intravenous contrast-enhanced MRI for diagnosis of adhesive capsulitis.

OBJECTIVES: We aimed to compare the reliability and performance of MRI measures enhanced with intravenous (IV) injection of gadolinium contrast versus non-enhanced MRI measures for the diagnosis of adhesive capsulitis (AC). We also aimed to examine the association between MRI findings and clinical features in patients with AC. METHODS: MRI of 42 patients with a clinical diagnosis of AC confirmed by arthrography and that of 42 patients in a control group were retrospectively studied by 2 blinded readers. Reliability and performance of MRI findings were compared between IV contrast-enhanced measures and non-enhanced MRI measures in T2-weighted fat-saturated and T1-weighted images. MRI findings were correlated with clinical stage, etiology, and pain. RESULTS: Sensitivity (97.6%) and specificity (97.6%) of axillary-recess capsule signal enhancement for AC diagnosis were significantly superior (p = 0.02) to hyperintense signals on T2-weighted fat-suppressed images (sensitivity 90.5%, specificity 92.7%). Measures of the intensity signal in the area of the rotator interval were less performant for AC diagnosis but could be improved with joint capsule enhancement. Moreover, we found very high specificity (100%) of enhancement of the coracohumeral ligament signal for AC diagnosis. The early stage of adhesive capsulitis was positively correlated with joint capsule enhancement in the rotator interval. Secondary etiology of capsulitis was correlated with joint capsule hyperintensity signals of the rotator interval on T2-weighted fat-suppressed images. CONCLUSION: IV contrast injection with MRI can be helpful for AC diagnosis in difficult cases. The stage of AC seems related to joint capsule enhancement in the rotator interval. KEY POINTS: • IV gadolinium-enhanced MRI can improve the analysis of signal changes in the shoulder synovium and capsule of the shoulder that are related to adhesive capsulitis. • As an original finding, we observed that coracohumeral ligament enhancement had a 100% specificity for the diagnosis of adhesive capsulitis. • The intensity of enhanced signals in the rotator interval seems to be related to the early stage of frozen shoulder.

Reduction of Metal Artifact with Dual-Energy CT: Virtual Monospectral Imaging with Fast Kilovoltage Switching and Metal Artifact Reduction Software.

Imaging of patients with metal implants is a common activity for radiologists, and overcoming metal artifacts during computed tomography (CT) is still a challenge. Virtual monochromatic spectral (VMS) imaging with dual-energy CT has been reported to reduce beam-hardening metal artifact effectively. Dual-energy CT allows the synthesis of VMS images. Monochromatic images depict how the imaged object would look if the X-ray source produced X-ray photons at only a single-energy level. For this reason, VMS imaging improve image quality by reducing beam-hardening artifacts. Additional metal artifact reduction postprocessing such as metal artifact reduction software can be applied to improve the visualization of the bone-prosthesis interface, periprosthetic areas, and soft tissue near and far from the metal implant. This article summarizes how virtual monochromatic images are synthesized from dual-energy CT, and it describes and illustrates our clinical experience with a single-source dual-energy scanner with fast kilovoltage switching to reduce beam hardening in patients with metal implants.

Hand and wrist involvement in systemic sclerosis: US features.

PURPOSE: To characterize ultrasonographic (US) features in the hand of patients with systemic sclerosis (SSc) and to evaluate the sensitivity of US in the detection of calcinosis and acroosteolysis. MATERIALS AND METHODS: The local ethics committee approved this study, and oral informed consent was obtained. A total of 44 consecutive patients with SSc (34 women; mean age, 56.1 years ± 12.1 [standard deviation]; 10 men; mean age, 45.0 years ± 14.0) and 30 healthy control subjects (20 women; mean age, 46.3 years ± 12.1; 10 men; mean age, 39.6 years ± 10.8) were included between October 2010 and December 2011. Bilateral US, including Doppler assessment of the wrists, hands, and fingers, was performed, and presence of synovitis, tenosynovitis with or without a layered appearance, calcifications, acroosteolysis, and distal vascularization was recorded. Radiography of both hands was performed to assess for acroosteolysis and calcinosis. Frequency of US features, sensitivity of US for calcinosis and acroosteolysis, and respective confidence intervals were calculated. RESULTS: Synovitis was found in 17 patients (39%). Tenosynovitis was found in 12 patients (27%), and it had a layered pattern in 15 (41%) of 37 cases. Calcinosis was found in 17 patients (39%) with US, with a sensitivity of 89%. Acroosteolysis was found in nine (20%) patients with US and in 10 (23%) patients with radiography, with 90% sensitivity for US. Distal vascularization was detected in 26 patients (59%) and 30 control subjects (100%) and was in contact with the acroosteolysis bed in seven (78%) of nine patients with SSc. CONCLUSION: US can be used to assess features of SSc, including synovitis, tenosynovitis, calcinosis, acroosteolysis, and distal vascularization and is sensitive for calcinosis and acroosteolysis detection. A layered pattern (similar to the appearance of an artichoke heart) of tenosynovitis was seen commonly. Online supplemental material is available for this article.

Occurrence of coring after needle insertion through a rubber stopper: study with prednisolone acetate.

OBJECTIVES: To evaluate the occurrence of coring after needle insertion through the rubber stopper of prednisolone acetate vials. METHODS: Two-hundred vials of prednisolone acetate were randomly distributed to two radiologists. Prednisolone acetate was drawn up through the rubber bung of the vials with an 18-gauge cutting bevelled needle and aspirated with a 5-ml syringe. The presence of coring was noted visually. We systematically put each core in a syringe refilled with 3 ml prednisolone acetate, and injected the medication through a 20-gauge spine needle. Computed tomography was performed to measure the size of each coring. RESULTS: Coring occurred in 21 out of 200 samples (10.5 %), and was visually detected in the syringe filled up with prednisolone in 11 of the 21 cases. Ten more occult cores were detected only after the syringes and needles were taken apart and rinsed. The core size ranged from 0.6 to 1.1 mm, and 1 of the 21 (4.7 %) cores was ejected through the 20-gauge needle. CONCLUSION: Coring can occur after the insertion of a needle through the rubber stopper of a vial of prednisolone acetate, and the resultant core can then be aspirated into the syringe.

Dorsal fractures of the triquetrum: MRI findings with an emphasis on dorsal carpal ligament injuries.

OBJECTIVE: The objective of our study was to report the MRI findings in dorsal fractures of the triquetrum, with an emphasis on dorsal carpal ligament injuries. MATERIALS AND METHODS: A total of 21 patients (16 men, five women; mean age, 41.9 years) with acute or subacute (≤ 6 weeks) dorsal triquetral fractures on radiography and MRI were included in this two-center retrospective study. MRI of the wrist was performed on 3-T units with transverse T1-weighted, coronal or transverse (or both) fat-suppressed T2weighted, transverse gadolinium-enhanced fat-suppressed T1-weighted turbo spin-echo, and 3D gadolinium-enhanced fat-suppressed T1-weighted gradient-recalled echo sequences. Three musculoskeletal radiologists evaluated the ulnar styloid process index (USPI) on radiographs and the following MRI features: fracture pattern (types 1-6), bone fragment size and displacement, bone marrow edema distribution, and dorsal carpal ligament tears. RESULTS: Eight type 1, one type 2, six type 3, five type 4, and one type 5 fractures were identified. These fractures were associated with 14 (66.7%), 17 (81.0%), and 16 (76.2%) tears of the dorsal radiocarpal, ulnotriquetral, and intercarpal ligaments, respectively. There was no correlation between bone marrow edema distribution and dorsal carpal ligament injuries (all p > 0.05). The mean (± SD) bone fragment volume and displacement were 205 ± 157 mm(3) and 1.0 ± 1.1 mm, respectively. The mean USPI was 0.21 ± 0.10. CONCLUSION: Dorsal fractures of the triquetrum are frequently associated with dorsal carpal ligament injuries. Bone marrow edema distribution is not correlated with these ligament tears.

Virtual monochromatic spectral imaging with fast kilovoltage switching: reduction of metal artifacts at CT.

With arthroplasty being increasingly used to relieve joint pain, imaging of patients with metal implants can represent a significant part of the clinical work load in the radiologist's daily practice. Computed tomography (CT) plays an important role in the postoperative evaluation of patients who are suspected of having metal prosthesis-related problems such as aseptic loosening, bone resorption or osteolysis, infection, dislocation, metal hardware failure, or periprosthetic bone fracture. Despite advances in detector technology and computer software, artifacts from metal implants can seriously degrade the quality of CT images, sometimes to the point of making them diagnostically unusable. Several factors may help reduce the number and severity of artifacts at multidetector CT, including decreasing the detector collimation and pitch, increasing the kilovolt peak and tube charge, and using appropriate reconstruction algorithms and section thickness. More recently, dual-energy CT has been proposed as a means of reducing beam-hardening artifacts. The use of dual-energy CT scanners allows the synthesis of virtual monochromatic spectral (VMS) images. Monochromatic images depict how the imaged object would look if the x-ray source produced x-ray photons at only a single energy level. For this reason, VMS imaging is expected to provide improved image quality by reducing beam-hardening artifacts.

Is superolateral Hoffa fat pad edema a consequence of impingement between lateral femoral condyle and patellar ligament?

PURPOSE: To evaluate whether knee extensor mechanism features are associated with superolateral Hoffa fat pad edema at magnetic resonance imaging. MATERIALS AND METHODS: Institutional review board approval and written consent from all patients were obtained. Patients with superolateral Hoffa fat pad edema (n = 30) and a control group without edema of the fat pad (n = 60) were evaluated prospectively with magnetic resonance (MR) imaging. Demographic data and extensor mechanism features were compared, including trochlear depth, lateral trochlear inclination, patellar tilt angle, patellar height ratio, distance between patellar ligament and lateral trochlear facet, distance from the tibial tubercle to the trochlear groove, patellar facet asymmetry, and patellar ligament abnormalities. RESULTS: The following variables were associated with superolateral Hoffa fat pad edema in the multivariable models: patellar height ratio (P = .023), shortest distance between patellar ligament and lateral trochlear facet (P < .001), and distance from the tibial tubercle to the trochlear groove (P = .046). Of all demographic and degenerative variables, only age was significantly associated, with younger patients more likely to have superolateral Hoffa fat pad edema (P < .009). CONCLUSION: A high-riding patella, a short distance between the patellar ligament and the lateral trochlear facet, and an increased distance from the tibial tubercle to the trochlear groove are associated with superolateral Hoffa fat pad edema at MR imaging. These results are suggestive of impingement between the lateral femoral condyle and the posterior aspect of the patellar ligament in these patients.

Imaging of hand and wrist cysts: a clinical approach.

OBJECTIVE: Ganglion cysts are common hand masses. This article will answer three questions that the radiologist is often asked: A mass is palpable; is it a cyst? Pain or neurologic symptoms are present; are they related to a cyst? Surgery is being considered; where precisely are the cyst and its origin located? CONCLUSION: Ultrasound is often sufficient for assessing typical cysts. MRI is performed when atypical features or neurologic symptoms are present and in specific preoperative settings.

Intra-articular botulinum toxin A injection for painful base-of-thumb osteoarthritis: a double-blind, randomised, controlled, phase 3 trial (RHIBOT).

BACKGROUND: Intra-articular botulinum toxin A injection might have analgesic effects in patients with joint diseases. We aimed to compare the effects of intra-articular botulinum toxin A injection with those of intra-articular saline injection for patients with painful base-of-thumb osteoarthritis. METHODS: RHIBOT was a double-blind, randomised, controlled, phase 3 trial conducted at Cochin Hospital, Paris, France. We recruited adult patients with x-ray evidence of trapeziometacarpal osteoarthritis who fulfilled the 1990 American College of Rheumatology criteria for hand osteoarthritis and reported a pain intensity score of at least 30 on an 11-point numeric rating scale (0: no pain to 100: maximal pain). Participants were randomly assigned (1:1), using a computer-generated randomisation list with permuted blocks of variable size (4 or 6), to receive an ultrasound-guided injection of either botulinum toxin A (50 Allergan units) in 1 mL of saline (experimental group) or 1 mL of saline alone (control group) in the trapeziometacarpal joint, in addition to custom-made rigid splinting. The primary outcome was the mean change from baseline in base-of-thumb pain in the previous 48 h on a numeric rating scale at 3 months after injection, analysed by intention to treat. This study is registered with ClinicalTrials.gov, NCT03187626. FINDINGS: Between Nov 2, 2018, and Nov 3, 2020, we assessed 370 individuals for eligibility and recruited 60 (16%) participants (mean age 64·9 years [SD 9·4], 47 [78%] women and 13 [22%] men), of whom 30 (50%) participants were randomly assigned to the experimental group and 30 (50%) to the control group. At baseline, base-of-thumb pain score was 60·0 of 100·0 (SD 15·9). At 3 months, the mean reduction in base-of-thumb pain was -25·7 (95% CI -35·5 to -15·8) in the experimental group and -9·7 (-17·1 to -2·2) in the control group (absolute difference -16·0 [-28·1 to -3·9]; p=0·043). Overall, 51 adverse events were reported in both groups: 27 (53%) in the experimental group and 24 (47%) in the control group. During follow-up, 14 (47%) participants in the experimental group and two (7%) participants in the control group reported mild transient motor deficit of the thenar muscle. No serious adverse events were reported. INTERPRETATION: Botulinum toxin A could be considered as a fast-acting, intra-articular therapy targeting chronic pain in individuals with base-of-thumb osteoarthritis. Future studies are needed to investigate the potential mechanism of the effects observed in this trial, to replicate our findings, and to assess the effects of repeated injections over time and their clinical effectiveness, including an analysis of cost-effectiveness. FUNDING: Assistance Publique-Hôpitaux de Paris.

Osteoid osteoma and osteoid osteoma-mimicking lesions: biopsy findings, distinctive MDCT features and treatment by radiofrequency ablation.

OBJECTIVE: To report the biopsy findings of osteoid osteoma (OO) and OO-mimicking lesions, assess their distinctive multidetector computed tomography (MDCT) features and evaluate treatment by radiofrequency ablation (RFA). METHODS: In this multicentric retrospective study, 80 patients (54 male, 26 female, mean age 24.1 years, range 5-48) with presumed (clinical and MDCT features) OO were treated by percutaneous RFA between May 2002 and June 2009. Per-procedural biopsies were always performed. The following MDCT features were assessed: skeletal distribution and location within the bone, size, central calcification, surrounding osteosclerosis and periosteal reaction. Clinical success of RFA was evaluated. RESULTS: Histopathological diagnoses were: 54 inconclusive biopsies, 16 OO, 10 OO-mimicking lesions (5 chronic osteomyelitis, 3 chondroblastoma, 1 eosinophilic granuloma, 1 fibrous dysplasia). OO-mimicking lesions were significantly greater in size (p = 0.001) and presented non-significant trends towards medullary location (p = 0.246), moderate surrounding osteosclerosis (p = 0.189) and less periosteal reaction (p = 0.197), compared with OO. Primary success for ablation of OO-mimicking lesions was 100% at 1 month, 85.7% at 6 and 12 months, and 66.7% at 24 months. Secondary success was 100%. CONCLUSION: Larger size, medullary location, less surrounding osteosclerosis and periosteal reaction on MDCT may help differentiate OO-mimicking lesions from OO. OO-mimicking lesions are safely and successfully treated by RFA.

Assessment of vascular invasion by bone and soft tissue tumours of the limbs: usefulness of MDCT angiography.

OBJECTIVE: To evaluate the accuracy of computed tomography angiography (CTA) in predicting arterial encasement by limb tumours, by comparing CTA with surgical findings (gold standard). METHODS: Preoperative CTA images of 55 arteries in 48 patients were assessed for arterial status: cross-sectional CTA images were scored as showing a fat plane between artery and tumour (score 0), slight contact between artery and tumour (score 1), partial arterial encasement (score 2) or total arterial encasement (score 3). Reformatted CTA images were assessed for arterial displacement, rigid wall, stenosis or occlusion. At surgery, arteries were classified as free or surgically encased; 45 arteries were free and 10 were surgically encased. RESULTS: Multivariate logistic regression identified the axial CTA score as a relevant predictor for arterial encasement and subsequent vascular intervention during surgery. All sites where CTA showed a fat plane between the tumour and the artery were classified as free at surgery (n = 28/28). The sensitivity of total arterial encasement on CTA (score 3) was 90%, specificity 93%, accuracy 93% and positive likelihood ratio 13.5. CONCLUSION: CTA evidence of total arterial encasement is a highly specific indication of arterial encasement. The presence of fat between the tumour and the artery on CTA rules out arterial involvement at surgery.

Intraoperative ultrasonography during percutaneous Achilles tendon repair.

BACKGROUND: The purpose of the study was to determine whether real-time intraoperative ultrasonography improved implant positioning and stump approximation in patients with acute Achilles tendon rupture managed percutaneously. MATERIALS AND METHODS: The needles were introduced percutaneously without ultrasonography and their position was checked relative to cutaneous landmarks and by palpation. Then, intraoperative ultrasonography was performed to assess needle position at the proximal tendon segment, tendon tear, and distal tendon segment. Incorrectly placed needles were removed and reinserted under real-time ultrasonographic guidance. Tendon apposition was checked ultrasonographically. RESULTS: We included 21 patients (19 males, two females) with unilateral acute Achilles tendon rupture, in whom 42 needles (one medial and one lateral) were inserted. Correct positioning was achieved without ultrasonographic guidance for 19 (45%) needles overall, 15 of 21 (71%) medial needles, and four of 21 (19%) lateral needles. The remaining 23 needles were correctly repositioned under ultrasonographic guidance. The correct positioning rates with and without ultrasonography differed significantly for all needles (p < 0.0001) and for lateral needles (p < 0.0001) but not for medial needles (p = 0.03). Intraoperative ultrasonography confirmed tendon stump approximation in all cases. CONCLUSION: Without imaging, 55% of needles were correctly positioned. Intraoperative ultrasonography allowed correct positioning of all needles and provided intraoperative confirmation of stump approximation.

Ultrasound features of painful intraosseous migration of pectoralis major tendinous calcifications with follow-up.

Calcific tendinitis is a common disorder in adults. Although rare, humerus involvement associated with pectoralis major tendon calcification migration has previously been reported in studies that focus on its CT and MRI appearance. We present four cases of intraosseous migration of pectoralis major tendon calcification and their ultrasound features. Calcification migration into osseous structures is associated with cortical erosions, intraosseous calcifications, and bone marrow edema. These findings may be misleading on MRI, where the significant bone marrow and surrounding tissue inflammation may raise concerns regarding neoplasia and lead to unnecessary invasive biopsy. In these cases, echography can be less alarming, enabling the identification of the calcification, its location in the pectoralis major tendon enthesis, and the continuity between the calcification and the typical cortical erosion. Ultrasound features may be diagnostic and might help avoid additional costly imaging studies or invasive biopsy.

Fractures of the ankylosed spine: MDCT and MRI with emphasis on individual anatomic spinal structures.

OBJECTIVE: The purpose of this article is to illustrate the spectrum of MDCT and MRI appearances of spinal fractures in ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis. CONCLUSION: Spinal fractures associated with ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis usually involve the three columns of the spine, and injury to the posterior osteoligamentous component is the hallmark of these fractures. Osseous and ligamentous injuries can be accurately visualized and analyzed with MDCT with multiplanar reformation and with MRI.

MRI assessment of recurrent carpal tunnel syndrome after open surgical release of the median nerve.

OBJECTIVE: The purpose of this study was to retrospectively determine the accuracy of MRI in identification of the morphologic features of median nerve dysfunction after surgical release of the median nerve for carpal tunnel syndrome. MATERIALS AND METHODS: Two blinded readers independently evaluated axial 1.5-T MR images for retinacular regrowth, morphologic characteristics of the median nerve, and presence of mass effect, fibrosis, and carpal tunnel decompression. All 47 patients (11 men, 36 women; mean age, 55 years; range, 27-81 years) had undergone open surgical release of the median nerve for carpal tunnel syndrome. Thirty-five patients had electromyographic evidence of recurrent carpal tunnel syndrome. The other 12 patients did not have electrophysiologic evidence of recurrent carpal tunnel syndrome and were the control group. RESULTS: A statistically significant difference between the recurrent carpal tunnel syndrome and control groups was found for fibrosis (p = 0.009), nerve enhancement (p = 0.04), and median nerve width (p = 0.008) and ratio (p = 0.01) at the pisiform level. CONCLUSION: MRI may be used in association with electromyography for accurate postoperative evaluation of the carpal tunnel.

Diagnostic imaging of solitary tumors of the spine: what to do and say.

Metastatic disease, myeloma, and lymphoma are the most common malignant spinal tumors. Hemangioma is the most common benign tumor of the spine. Other primary osseous lesions of the spine are more unusual but may exhibit characteristic imaging features that can help the radiologist develop a differential diagnosis. Radiologic evaluation of a patient who presents with osseous vertebral lesions often includes radiography, computed tomography (CT), and magnetic resonance (MR) imaging. Because of the complex anatomy of the vertebrae, CT is more useful than conventional radiography for evaluating lesion location and analyzing bone destruction and condensation. The diagnosis of spinal tumors is based on patient age, topographic features of the tumor, and lesion pattern as seen at CT and MR imaging. A systematic approach is useful for recognizing tumors of the spine with characteristic features such as bone island, osteoid osteoma, osteochondroma, chondrosarcoma, vertebral angioma, and aneurysmal bone cyst. In the remaining cases, the differential diagnosis may include other primary spinal tumors, vertebral metastases and major nontumoral lesions simulating a vertebral tumor, Paget disease, spondylitis, echinococcal infection, and aseptic osteitis. In many cases, vertebral biopsy is warranted to guide treatment.

Sonographic appearance of trigger fingers.

OBJECTIVE: The purpose of this study was to describe the sonographic appearance of the first annular (A1) pulley-flexor tendon complex in patients with trigger fingers. METHODS: Thirty-three trigger fingers in 33 patients were examined with a 7- to 15-MHz probe. A control group consisted of 20 patients without trigger fingers. The study included systematic measurement of the thickness of the A1 pulley and a power Doppler assessment of the pulleys, tendons, and tendon sheaths. RESULTS: Thickening and hypoechogenicity of the A1 pulley were found in all patients with trigger fingers. Measurements of A1 pulley thickness were significantly different (P < .0001) between the groups without trigger fingers (mean, 0.5 mm; range, 0.4-0.6 mm) and with trigger fingers (mean, 1.8 mm; range, 1.1-2.9 mm). Hypervascularization of the A1 pulley on power Doppler imaging was found in 91% of the trigger fingers but was never found in the healthy control group. Flexor tendinosis was found in 48% of the trigger fingers; tenosynovitis was found in 55%; and both were found in 39%. In the control group, tenosynovitis and tendinosis were not found. CONCLUSIONS: Thickening and hyper-vascularization of the A1 pulley are the hallmarks of trigger fingers on sonography. Other frequently observed features include distal flexor tendinosis and tenosynovitis.

Intra-articular botulinum toxin A for base-of-thumb osteoarthritis: protocol for a randomised trial (RHIBOT).

INTRODUCTION: Recent studies have suggested that intra-articular injection of botulinum toxin A (BTA) may have analgesic effects in degenerative joint diseases. We aim to assess the efficacy of intra-articular injection of BTA associated with splinting in patients with trapeziometacarpal osteoarthritis (TMC OA). METHODS AND ANALYSIS: We will conduct a randomised double-blind controlled trial. Overall, 60 individuals with TMC OA fulfilling adapted 1990 American College of Rheumatology criteria for hand OA will be recruited in one tertiary care centre in France and randomised to receive splinting + a single ultrasound-guided injection in the TMC joint of 50 Allergan Units of BTA resuspended in 1 mL saline or splinting +1 mL saline. Randomisation will be centralised. The allocation ratio will be 1:1. The primary outcome will be the mean change from baseline in base-of-thumb pain on a self-administered 11-point Numeric Rating Scale in 10-point increments at 3 months after injection. Secondary outcomes will be the mean change in base-of-thumb pain at 1 and 6 months, mean change in hand-specific activity limitations assessed by the self-administered Cochin Hand Function Scale, proportion of responders assessed by the Osteoarthritis Research Society International -Outcome Measures in Rheumatology (OMERACT) criteria and consumption of analgesics and non-steroidal anti-inflammatory drugs assessed by a self-administered 4-class scale at 3 and 6 months. Cointerventions will be allowed in both groups and will be self-reported. Adverse events will be recorded at 3 and 6 months. Participants, care providers and statisticians will be blinded to the allocated treatment. ETHICS AND DISSEMINATION: The RHIBOT trial has been authorised by the Agence Nationale de Sécurité du Médicament and approved by the Comité de Protection des Personnes de Tours Ouest-1. The findings of the study will be disseminated in peer-reviewed journals and at conferences. If the results are positive, intra-articular BTA could be an efficient and safe complementary therapeutic option for patients with TMC OA. DATE AND VERSION IDENTIFIER OF THE PROTOCOL: 8 January 2018, V. 2.0. TRIAL REGISTRATION NUMBER: NCT03187626; Pre-results.