Subscapularis impairment on magnetic resonance imaging is correlated with functional limitations in neonatal brachial plexus palsy.

PURPOSE: The relationship between functional shoulder deficits in children with neonatal brachial plexus palsy (NBPP) and magnetic resonance imaging (MRI) shoulder abnormalities was evaluated. METHODS: Shoulder function was assessed in 16 children (mean age: 5.8 years; range: 3-12 years) with NBPP based on shoulder rotator muscle strength, as measured using an isokinetic dynamometer and the modified Mallet score. The thickness and fatty infiltration of the subscapularis and infraspinatus muscles, and the morphology of the glenoid on MRI, were also determined. RESULTS: The highest subscapularis fatty infiltration subgroup of NBPP patients promoted the highest alteration muscle thickness and modified Mallet score. CONCLUSIONS: In NBPP children, subscapularis impairments play a major role in the functional limitations. This study of pediatric NBPP patients highlighted the value of adding an examination of the muscles to routine MRI assessment of bone parameters in the shoulders of NBPP children. TRIAL REGISTRATION: NCT03440658.

Esophageal perforation caused by a thoracic pedicle screw.

This grand round raises the risk of a rare complication that can be avoided with the knowledge of the particular anatomy of scoliosis vertebra. Transpedicular screws have been reported to enhance the operative correction in scoliosis surgery. The narrow and inconsistent shape of the thoracic pedicles makes the placement of pedicle screws technically challenging. Furthermore, in thoracic curves, the close proximity of the spinal cord and major soft tissue structures also adds a greater risk to the procedure. The esophagus lies close to the upper thoracic vertebras and, an anterior cortical perforation can cause esophageal injury. We report a case of anterior cortical perforation by a T4 pedicle screw complicated by an esophageal perforation in a 15-year-old girl with convulsive encephalopathy. She was operated for a severe neurological scoliosis (Rett syndrome). Her neurological condition deteriorated 3 years after the posterior spinal surgery, requiring a percutaneous gastrostomy. An intra-esophageal screw was discovered incidentally during an endoscopy. We decided not to remove this screw, because the patient's health status presented a surgical contraindication. The patient showed no apparent discomfort at the 10-year follow-up examination after spinal arthrodesis. Esophageal perforation caused by a posterior pedicle screw is very rare. We highlight the risk of injury to esophagus from pedicle screws in upper thoracic vertebra. The systematic removal of a malpositioned screw must be discussed, on a case-to-case benefit-risk basis, especially if the patient has numerous comorbidities, given the long-term tolerance of a number of these improperly positioned implants.

Change in shoulder external rotation strength and motion after lower trapezius transfer to the infraspinatus in children with obstetric brachial plexus palsy.

PURPOSE: Quantifying changes in shoulder external rotation range of motion and strength after lower trapezius transfer in children with obstetric brachial plexus palsy (OBPP). METHODS: This prospective study included five children with sequelae of OBPP, with a mean age of 6.4 years (range: 4-12 years) who underwent lower trapezius tendon transfer to restore active external rotation (ER) of the shoulder. Pre-operatively and at a 12-month follow-up assessment, we analyzed the passive and active shoulder ER, the modified Mallet score, and the shoulder rotator muscles strength using an isokinetic device. RESULTS: Clinical parameters improved significantly after trapezius transfer pre-operative passive ER from -8° (range: -20-0°) to 37° (range: 15-50°) (p = 0.035), the modified Mallet score from 13 (range: 10-15) to 18 (range: 17-19) (p = 0.035). Strength testing revealed improved ER muscle strength in all five cases; the mean Peak Torque increased from 1.95 to 4.46 N·m, albeit non-significantly (p = 0.062). Two patients exhibited a winged scapula post-operatively. CONCLUSION: Lower trapezius transfer seems encouraging to restore shoulder external rotation in OBPP children but with non-significant strength improvement. TRIAL REGISTRATION: 18/07/31/5783, December 22, 2018.

Does arthroscopic resection of a too-long anterior process improve static disorders of the foot in children and adolescents?

PURPOSE: A too-long anterior process of the calcaneus is a common cause of pain and hind-foot instability. Our goal was to evaluate the early results of arthroscopic resection in terms of static foot disorders in children and adolescents. METHODS: We retrospectively studied 11 ft (10 patients). The inclusion criteria were treatment of TLAP by arthroscopic resection and a minimum follow-up period of six months. Surgery was indicated in cases with persistent symptomatic TLAP resistant to orthopaedic treatment. RESULTS: The mean age at surgery was 11 (range, 7-15) years. The mean follow-up duration was 15 (range, 8-28) months. Pre-operatively, we diagnosed four flat feet, two cavus feet and five feet with normal footprints, but loss of physiological hind-foot valgus. All patients presented with subtalar joint stiffness. At the last follow-up, four feet with no hind-foot valgus were normal, two were unchanged and the other feet had improved. The mean AOFAS increased from 61.9 (range, 47-73) to 89.1 (range, 71-97; P = 0.009). The mean radiological angles were near normal, exhibiting significant improvements in the lateral talo-metatarsal and Djian-Annonier angles. CONCLUSIONS: Arthroscopic resection of a TLAP is safe. In the short term, the restoration of subtalar mobility reduces pain, and improves instability and static disorders. Longer follow-up of a larger patient series is required.

Long-term Results After Extensive Soft Tissue Release in Very Severe Congenital Clubfeet.

BACKGROUND: The purpose of this study was to determine the long-term results, at an average follow-up of 22 years, in 66 patients (105 clubfeet) with very severe congenital idiopathic clubfeet according to the Dimeglio-Bensahel scale. METHODS: Patients were treated with an extensive soft tissue release in infancy. Results of the treatment were assessed according to the 100-point system of Ghanem-Seringe. At the latest follow-up, all participants were evaluated with regard to pain and the overall function of the lower extremities. At the latest follow-up, anteroposterior and lateral radiographs of the affected foot and the contralateral normal foot, when applicable, were performed. RESULTS: In total, 92% of the patients were satisfied. The mean functional score of Ghanem-Seringe was 70.4 points. No foot had an excellent result, 19 feet had a good result, 16 had a fair result, and 70 had a poor result. A total of 86 feet were painful after strenuous activities or during walking. Eleven patients walked with a limp. In total, 82 feet were stiff. Ankle dorsiflexion and plantar flexion averaged 4.0±4.5 degrees and 19.9±10.7 degrees. Bone deformations such as flattening of the talar dome were observed in 93 feet. Among these feet, the Ghanem score was significantly lower (P<0.05). Necrosis of the navicular was present in 28 feet and subluxation in 82 feet. In total, 32 feet had moderate osteoarthritis. DISCUSSION: Results revealed that despite anatomically and radiologically imperfect clubfeet, most patients demonstrated satisfaction. Satisfaction was not significantly correlated with residual deformity, but with the sensation of a normal gait by the patient and the high initial Dimeglio-Bensahel score. Female patients were significantly less satisfied than male patients because they were more constrained in their social life than boys. Their main dissatisfaction was the atrophy of the calf. We noted several residual deformations. Plantar release seems to contribute to the high rate of overcorrection in our series. Extensive posterolateral and plantar releases in very severe clubfeet was responsible for sequelae, morphologic, anatomic, and functional, especially in adulthood. Deterioration of results over time was confirmed by our series. LEVEL OF EVIDENCE: Level IV.

The Use of Magnetic Resonance Imaging in Management of Minimally Displaced or Nondisplaced Lateral Humeral Condyle Fractures in Children.

OBJECTIVES: Fractures of the lateral humeral condyle are common in children. Nondisplaced fractures are managed with cast immobilization and frequent radiographic follow-up. Possibility of assessing the displacement and stability of such fractures may be helpful in planning the initial treatment and survey. Magnetic resonance imaging (MRI) could be a useful tool in determining the stability of lateral condyle in children. We propose to investigate the use of MRI in such indication. METHODS: Fourteen patients presenting with a minimally displaced or nondisplaced fracture were initially treated with a long arm cast and had an MRI within 5 days of injury. RESULTS: The MRI showed that 10 patients had an incomplete fracture without disruption of the cartilage hinge and 4 patients had a complete fracture with extension of the fracture through the cartilaginous epiphysis into the elbow joint. Three patients with such complete fracture had no evidence of lateral condyle displacement on MRI, and 1 patient had a displacement of the lateral condyle. The patients with incomplete fractures had a conservative treatment. The patient with a complete and displaced fracture had an open reduction and internal fixation. The 3 patients with a complete fracture and no evidence of lateral condyle displacement on MRI had a control MRI, 6 to 10 days after cast application, to detect a secondary displacement of the fracture. CONCLUSIONS: Because it seems difficult in minimally displaced or nondisplaced fractures to detect further displacement with radiographs, MRI was found mandatory to improve complete fracture visualization during the first phase of conservative treatment. In incomplete fractures, initial MRI investigation was consistent with a stable fracture and avoided further early radiographs or clinical survey. In such cases, we recommend a conservative treatment with late radiographs after long arm cast removal. We propose MRI routine use in the early evaluation of minimally displaced or nondisplaced lateral condyle fractures in children.

Autologous osteochondral mosaicplasty in osteochondritis dissecans of the patella in adolescents.

PURPOSE: Osteochondritis dissecans of the patella (OCDP) is rare in adolescents. The objective of this study was to evaluate functional results of OCDP management in adolescents with mosaicplasty and to analyze proper integration of osteochondral grafts via MRI. METHODS: This is a retrospective series of eight cases of OCDP treated by mosaicplasty. Mean age at the surgery was 15 years (range 12-17). Clinical features were represented by retropatellar pain, hydarthrosis, locking and crepitus. All patients benefited from knee radiographs as well as pre-operative MRI. Six OCDP were evaluated International Cartilage Repair Society (ICRS) grade III and two were ICRS grade IV. Mean surface of the lesion was 97.5 mm2. The pre- and post-operative assessments were conducted with scores obtained on the IKDC subjective knee evaluation form, Lysholm knee score, and Tegner activity scale. These assessments were completed by post-operative MRI. The magnetic resonance observation of cartilage repair tissue (MOCART) score was calculated from the latest MRI examination conducted after surgery. RESULTS: Mean follow-up was 28.6 months. At the latest follow-up, the mean IKDC score was 86.5, Lysholm score was 89, and Tegner activity scale score was 6.2 (pre-operative scores were respectively 49.9, 53.8, and 4.5). Radiographs and MRI showed a complete integration of grafts at the latest follow-up with a satisfactory reconstruction of the joint surface. Mean MOCART score was 75/100. CONCLUSIONS: Autologous osteochondral mosaicplasty to manage OCDP in adolescents appears to be a reliable technique on the short term to restore patellar joint surface and obtain satisfactory functional results.

CoCr rods provide better frontal correction of adolescent idiopathic scoliosis treated by all-pedicle screw fixation.

PURPOSE: Pedicle screw fixation is considered biomechanically advantageous in adolescent idiopathic scoliosis (AIS) correction, because it uses as an anchor the pedicle, which is the hardest part of the vertebral body. The ability of the rod to correct and hold the correction is a key factor in the selection of rod material. The goal of this study was to compare the results obtained by stainless steel (SS) and cobalt-chromium (CoCr) rods materials for the treatment of AIS curves. METHODS: Ninety patients were retrospectively included. Sixty-four patients (group 1) were operated on using CoCr rods. Twenty-six patients (group 2) were operated on using SS rods. All the patients were treated by the same surgeon using all-pedicle screw constructs. RESULTS: In group 1, the correction was respectively 41.03° and 35.78° for main and secondary curves. In group 2, the correction was respectively 30.98° and 24.42° for main and secondary curves. Statistical analysis showed improved correction rates in patients operated with CoCr rods for main (P < 0.0001) and secondary (P = 0.0003) curves with a lower loss of correction at final follow-up. Regarding the sagittal profile, postoperative T4T12 thoracic kyphosis was 28.04° in CoCr group compared to 22.79° in SS group (P = 0. 0.0038). DISCUSSION: The present study confirms the ability of the all-pedicle screw construct to reach the maximum coronal plane correction and prevent deformity progression while maintaining balance. CoCr rods have the ability to exert higher corrective forces on the spine with relatively small amounts of rod deformation. Our findings confirm that CoCr rods have the ability to produce higher correction rates in frontal plane compared to SS rods of the same diameter.

A new technique for proximal femoral resection in non-ambulatory patients with cerebral palsy.

Proximal femoral resection may be proposed to non-ambulatory patients with cerebral palsy and chronic painful hip dislocation. McCarthy's technique confers good results but does not solve the problems related to femoral reascension (bone migration causing painful osseous or cutaneous conflict). We describe a new technique of resection-interposition of the proximal end of the femur which preserves the greater trochanter by an orthogonal osteotomy below the lesser trochanter while maintaining the gluteal-vastus lateralis strut in continuity. A suture of the remaining joint capsule upon itself and a trans-trochanteric capsulodesis are associated to stabilize the cephalic displacement of the femur.

Minimally invasive treatment of aneurysmal bone cysts: Systematic literature review.

INTRODUCTION: The optimal treatment of aneurysmal bone cysts (ABC) remains controversial. Surgery has long been considered as the treatment that yields the best outcomes. Some authors now prefer using less invasive options as the primary treatment. The primary objective of this systematic literature review was to determine if treatments that are less invasive than surgery are also effective in curing the ABC. The secondary objective was to determine the respective role of each treatment in the therapeutic arsenal. HYPOTHESIS: Less invasive treatments can replace surgery as the base treatment for ABC. PATIENTS AND METHODS: A PubMed® search was carried out for this review. The inclusion criteria were ABC treatment without cyst removal, case series, clinical case reports, reviews, publication in French or English. Excluded were articles that described the results of surgical treatment only, cranial or maxillofacial cysts, secondary ABC, duplicates, no abstract available. Based on the first six items of the "MINOR criteria", we selected 42 studies. For each selected study, we analyzed the number of cases, clinical response to treatment, radiological healing, recurrence or failure rate, complications and side effects of the treatment. RESULTS: This review found that less invasive treatments generate results that are at least as good as surgery, often with fewer complications. Thus, in certain cases, these treatments can be recommended as first-line therapy. This category includes selective arterial embolization, sclerotherapy (alcohol, polidocanol) and injection of demineralized bone matrix. DISCUSSION: Selective arterial embolization yields good results. While this is a difficult, operator-dependent technique that is not suitable for all ABCs (no identifiable feeding vessel), we recommend it as the primary treatment for spinal ABCs. For ABCs in other locations, sclerotherapy can be used as the primary treatment. However, this treatment becomes inconvenient if the number of injections is too high. Radiation therapy is not a first-line treatment because of its side effects. Bisphosphonates and denosumab can be used when the other treatments are contraindicated.

Closed reduction by trans-physealantegrade elastic stable intramedullary nailing in acute pediatric Monteggia fractures: a report of 22 cases.

Treatment of acute pediatric Monteggia fractures is still debated. The aim of this study was to assess the efficacy of strategy based on closed reduction by trans-physeal antegrade elastic stable intramedullary nailing (ESIN) of the ulnar fracture. Retrospective analysis of 22 patients (13 boys and nine girls) treated for acute Monteggia fractures between May 2008 and August 2018 was performed. Mean age at injury was 6.6 years. Mean follow-up was 4.5 years. On the basis of the Bado classification, 15 lesions were of type I, three types III and four types IV. All the patients were managed with closed reduction and ESIN of the ulna fracture within 2-19 h of arrival. Intraoperative stability of reduction of the radial head was checked under fluoroscopic control in pronation and supination. Outcomes were assessed with the Bruce et al. scoring system. Closed alignment of the ulnar fracture by ESIN had simultaneously reduced and stabilized the radial head dislocation in all patients. At the final follow-up, all the patients had excellent results. Complete healing of the fracture occurred in 6 weeks and the elastic nail removed at 3-6 months postoperatively. There was no case of instability or subluxation or re-dislocation of the radial head. No olecranon epiphysiodesis or growth disorders were noticed. Early diagnosis and management of acute pediatric Monteggia fractures by closed reduction and ESIN achieve excellent clinical and radiographic outcomes.

Is there a persistent capital femoral epiphysis growth after screw fixation for slipped capital femoral epiphysis?

Femoral neck screwing during child development is controversial. The objective of this study was to evaluate the residual growth of the capital femoral physis after screw fixation. This retrospective study included children aged younger than 12 years treated for slipped capital femoral epiphysis (SCFE) with a single percutaneous partially threaded cannulated screw. The children were followed up for at least 1 year. Some patients also underwent prophylactic contralateral screwing. Preoperative, immediate postoperative and final follow-up X-rays were evaluated to determine the degree of slippage, pin-joint ratio (PJR), neck-pin ratio (NPR), number of threads crossing the physis, neck-shaft angle (NSA), screw-physis angle and screw position in the physis. We included 17 patients (29 hips: 18 SCFE and 11 prophylactic) with a mean age of 10.1 years (range: 7.1-11.9 years) at the time of surgery. Significant evolution of radiological growth parameters of the proximal femoral physis was noted during a mean follow-up of 2.4 years (range: 1-4.3 years). The mean PJR significantly decreased from 7.3 to 6.0, the mean NPR significantly decreased from 106 to 96 and the mean number of threads beyond the physis decreased from 3.3 to 1.8. The mean NSA decreased by 6.5°, from 139° to 132.5°. Persistent capital femoral epiphysis growth occurs after screw fixation. The NSA significantly decreases over time but remains within the physiological limits. Level of evidence: IV (case series).

Acetabular retroversion after triple pelvic osteotomy for Legg-Calvé-Perthes disease and its impact on the femoroacetabular impingement: a case/control study at 15 years of follow-up.

The objective of this study was to compare the effect of triple pelvic osteotomy (TPO) in Legg-Calvé-Perthes disease (LCPD) on acetabular version in a group of patients who developed a femoroacetabular impingement (FAI) and a control group without FAI. Patients who received a TPO for unilateral LCPD were retrospectively included. Patients with bilateral LCPDs, requiring TPO with femoral procedures, or with incomplete imaging were excluded. Seven patients with FAI (FAI+) and eight patients without FAI (FAI-) were evaluated at a mean follow-up of 14.8 years. The two groups were comparable in demographic data, age at diagnosis, Herring score, and BMI. We measured anatomical acetabular version on computed tomography scans, the difference (delta) of acetabular version between the operated hip and the healthy hip, the McKibbin (femoral version + acetabular version), Stulberg, and Tönnis scoring system. The two groups were not statistically different on the Stulberg and Tönnis scores. All operated hip acetabula were retroverted, FAI+: -8.41° (range, -44 to 10.5), FAI-: -3.38° (range, -37.3 to 11.5) (P = 0.61). The average delta was FAI+: 23.79° (range, 1.5-59.5), FAI-: 20.14° (range, 5-45.3) (P = 0.68). All seven patients of the FAI+ group have pathologic McKibbin index (<30°) versus only four of the FAI- group (P = 0.03). TPO induces acetabular retroversion in patients with LCPD. This retroversion, assessed in a static benchmark (anterior pelvic plane), does not in itself explain the FAI.

Dysplasia Epiphysealis Hemimelica Presenting as Multiple Loose Bodies: A Case Report.

CASE: A 11-year-old boy with no medical history presented with a protective limp and worsening mechanical pain in his left knee. No recent traumatic or infectious history was reported. Radiographs and ultrasonography showed multiple intra-articular loose bodies with osteocartilaginous signal. Dysplasia epiphysealis hemimelica (DEH) was confirmed by magnetic resonance imaging (MRI) and computed tomography (CT) scan. This is the first report that describes the presence of loose bodies in a knee without previous surgery as a possible case of DEH. CONCLUSION: We emphasize the use of CT scan and MRI before any surgical procedure when intra-articular loose bodies are unexpectedly discovered.

Medium-term results of calcaneus lengthening in idiopathic symptomatic flat foot in children and adolescents.

PURPOSE: Calcaneus lengthening can be used in symptomatic flat foot in children, but few details on its medium-term results and complementary procedures are available. METHODS: A total of 20 flexible, symptomatic, idiopathic valgus flat feet (in 15 children; mean age 13.9 years (10 to 17)) were operated on. Complementary procedures were based on preoperative and intraoperative analyses. Radiographic measurements were obtained preoperatively and with at least four years follow-up. RESULTS: At a mean of 8.3 years (4 to 15) postoperatively, 13 feet had good clinical and radiological results, with significant improvement in American Orthopaedic Foot & Ankle Society Ankle-Hindfoot scale scores and radiological measurements. Seven feet had residual pain. Six of them had no osteotomy of the first cuneiform. CONCLUSION: Calcaneus lengthening with adequate complementary musculo-tendinous and/or bone procedures according to preoperative and intraoperative foot deformation leads to good medium-term results. Forefoot supination is the most frequent residual defect. If present intraoperatively, first cuneiform pronation-flexion osteotomy is indicated. LEVEL OF EVIDENCE: IV.

Peer Role-Play for Training Communication Skills in Medical Students: A Systematic Review.

STATEMENT: Peer role-play (PRP) is a simulation-based training method (SBTM) in which medical students alternately play the patient's and clinician's role. This review aimed to assess the effectiveness of PRP for improving the communication skills of medical students. A systematic search was conducted in the MedLine, PsycInfo, and ERIC databases. Studies were qualitatively analyzed according to the Kirkpatrick evaluation level (Kirkpatrick level) and the Medical Education Research Study Quality Instrument.Twenty-two studies were included. Studies assessing the "reaction" of students (Kirkpatrick level 1, n = 15) found that PRP was appreciated, whereas those assessing the effect of PRP on "learning" (Kirkpatrick level 2, n = 12) found that PRP improves communication skills but no more than other SBTMs. No study assessed real-life "attitudes" or "clinical outcomes" (Kirkpatrick levels 3 and 4), whereas 2 studies found that using PRP had a better cost-efficacy ratio than the use of simulated patients. Compared with other SBTMs, PRP improved communication skills similarly in medical students and seemed less expensive.

Differential Accumulation and Activation of Monocyte and Dendritic Cell Subsets in Inflamed Synovial Fluid Discriminates Between Juvenile Idiopathic Arthritis and Septic Arthritis.

Despite their distinct etiology, several lines of evidence suggest that innate immunity plays a pivotal role in both juvenile idiopathic arthritis (JIA) and septic arthritis (SA) pathophysiology. Indeed, monocytes and dendritic cells (DC) are involved in the first line of defense against pathogens and play a critical role in initiating and orchestrating the immune response. The aim of this study was to compare the number and phenotype of monocytes and DCs in peripheral blood (PB) and synovial fluid (SF) from patients with JIA and SA to identify specific cell subsets and activation markers associated with pathophysiological mechanisms and that could be used as biomarkers to discriminate both diseases. The proportion of intermediate and non-classical monocytes in the SF and PB, respectively, were significantly higher in JIA than in SA patients. In contrast the proportion of classical monocytes and their absolute numbers were higher in the SF from SA compared with JIA patients. Higher expression of CD64 on non-classical monocyte was observed in PB from SA compared with JIA patients. In SF, higher expression of CD64 on classical and intermediate monocyte as well as higher CD163 expression on intermediate monocytes was observed in SA compared with JIA patients. Moreover, whereas the number of conventional (cDC), plasmacytoid (pDC) and inflammatory (infDC) DCs was comparable between groups in PB, the number of CD141+ cDCs and CD123+ pDCs in the SF was significantly higher in JIA than in SA patients. CD14+ infDCs represented the major DC subset in the SF of both groups with potent activation assessed by high expression of HLA-DR and CD86 and significant up-regulation of HLA-DR expression in SA compared with JIA patients. Finally, higher activation of SF DC subsets was monitored in SA compared with JIA with significant up-regulation of CD86 and PDL2 expression on several DC subsets. Our results show the differential accumulation and activation of innate immune cells between septic and inflammatory arthritis. They strongly indicate that the relative high numbers of CD141+ cDC and CD123+ pDCs in SF are specific for JIA while the over-activation of DC and monocyte subsets is specific for SA.

Synovial-Fluid miRNA Signature for Diagnosis of Juvenile Idiopathic Arthritis.

Juvenile idiopathic arthritis (JIA) is the most common chronic inflammatory rheumatism in childhood; microRNAs (miRNAs) have been proposed as diagnostic biomarkers. Although joints are the primary targets for JIA, a synovial fluid-based miRNA signature has never been studied. We aim to identify miRNA biomarkers in JIA by comparing synovial fluid and serum samples from children with JIA and K.kingae septic arthritis (SA). With next-generation high-throughput sequencing, we measured the absolute levels of 2083 miRNAs in synovial fluid and serum from an exploratory cohort of children and validated differentially expressed miRNAs in a replication study by using RT-qPCR. We identified a 19-miRNA signature only in synovial fluid samples that was significantly deregulated, with at least 2-fold change in expression, in JIA versus SA (p < 0.01). The combination of miR-6764-5p, miR-155, and miR-146a-5p expression in synovial fluid yielded an area under the receiver operating characteristic curve of 1 (95% CI 0.978 to 1), thereby perfectly differentiating JIA from SA in children. We propose, for the first time, a synovial fluid-specific miRNA signature for JIA and associated signaling pathways that may indicate potential biomarkers to assist in the classification and differential diagnosis of JIA and help in understanding JIA pathogenesis.