A threshold value of 3.5 mm of passive anterior tibial subluxation on MRI is highly specific for complete ACL tears.

PURPOSE: To identify and quantify passive anterior tibial subluxation on MRI using a standardized measurement protocol and determine the diagnostic threshold of subluxation for complete anterior cruciate ligament tears. METHODS: A retrospective case-control study was performed. Patients who underwent surgery for a complete isolated ACL tear between 2009 and 2015 were matched for age and gender to controls with an intact ligament on knee MRI. All subjects underwent 1.5 T closed field MR imaging with the same protocol. Measurements were performed on axial sequences to evaluate translation of the medial and lateral condyles compared to the tibial plateau. Each compartment was measured between the vertical tangent to the posterior femoral condyles and the most posterior part of the tibial plateau. The main criterion was global passive subluxation measurements on MRI, corresponding to mean medial and lateral compartment subluxation. The reproducibility and diagnostic value of passive subluxation were calculated. RESULTS: Sixty (30/30) subjects were included, mean age 27.1 ± 1.7 years, 20 women and 40 men. Patients had a significantly higher global passive subluxation than controls (3.3 ± 0.6 mm vs 0.6 ± 0.2 mm, respectively p < 0.00001). Reproducibility was excellent and the diagnostic value of passive subluxation for a complete ACL tear was fair. A passive subluxation threshold of 3.5 mm had a sensitivity of 55.2%, a specificity of 100% and 77.6% of well-classified subjects. CONCLUSION: The calculated cutoff value for global passive subluxation to identify patients with a complete ACL tear was 3.5 mm, with excellent specificity and a high positive likelihood ratio. Suboptimal clinical results following ACL reconstruction could be partially due to failure to restore an anatomical femorotibial relationship. LEVEL OF EVIDENCE: III.

How to diagnose spondyloarthritis early? Accuracy of peripheral enthesitis detection by power Doppler ultrasonography.

OBJECTIVE: Early diagnosis of spondyloarthritis (SpA) is sometimes difficult owing to the lack of reliable diagnostic criteria. The objective of this study was to determine the diagnostic accuracy of detecting enthesitis by power Doppler ultrasonography (PDUS) in patients with suspected SpA. METHODS: A prospective single-centre cohort study was performed in patients with symptoms suggestive of SpA (inflammatory back pain, arthritis, enthesitis or dactylitis, HLAB27+ uveitis) who underwent clinical examination, pelvic x-ray, MRI of lumbar spine/sacroiliac joints, HLA-B typing and other tests judged useful for diagnosis. Blinded PDUS examination of seven sites of enthesitis was performed at baseline. The gold standard was the diagnosis made by the referring rheumatologist according to the development of symptoms and findings, blinded to PDUS results, during routine follow-up for up to 2 years. RESULTS: Between November 2002 and October 2004, 118 patients were included in the study. After 2 years a definite diagnosis was retained for 99 patients (51 SpA and 48 non-SpA). PDUS detection of at least one vascularised enthesis provided good predictive value for diagnosing SpA (sensitivity 76.5%; specificity 81.3%; positive likelihood ratio 4.1; OR 14.1; p<0.0001). Vascularised enthesitis detected by PDUS and Amor's criteria were the only independent contributors to a diagnosis of SpA in multivariate logistic regression (c-index=0.87). Alternatively, CART analysis resulted in a highly sensitive and specific diagnostic tree by combining PDUS with Amor's criteria. CONCLUSIONS: PDUS appears to be a valuable first-line diagnostic tool to confirm a diagnosis of SpA.

Risk factors for passive anterior tibial subluxation on MRI in complete ACL tear.

INTRODUCTION: In anterior cruciate ligament (ACL) tear, passive spontaneous anterior tibial subluxation (ATS), with respect to the femur, is sometimes observed on MRI. In a case-control study, ATS>3.5mm showed 100% specificity (±3.6, 95% CI) for complete ACL tear. The aim of the present study was to assess the relation between ATS on MRI and associated lesions in complete ACL tear. The study hypothesis was that associated lesions are a risk factor for ATS. MATERIAL AND METHODS: A retrospective study included patients operated on for complete ACL tear between 2010 and 2015. Exclusion criteria comprised associated posterior cruciate ligament tear, partial ACL tear, and history of knee surgery. Preoperative MRI was performed with the patient in supine position and the knee in 20° flexion in neutral rotation. ATS was measured by axial superimposition of the bicondylar slice on the slice through the tibial plateau. Associated lesions were assessed: medial and lateral menisci, collateral ligaments, posteromedial and posterolateral corners, tibiofemoral compartment cartilage and cancellous bone. Factors associated with ATS>3.5mm were analyzed. Ninety-one patients were included: mean age, 31.1±10.1 years; 34 female, 57 male. Mean time from injury to MRI was 7.8±11.7 months (range, 0.7-60 months). RESULTS: Mean ATS was 4.7±2.3mm. Inter- and intra-observer reproducibility for ATS measurement were excellent. On preoperative MRI, 61.1% of patients showed bone edema, 48.4% medial meniscal tear, and 36.3% lateral meniscal tear. ATS was significantly greater in case of medial meniscal tear (5.4±2.3mm vs. 4±2.1mm; p=0.003). No significant differences were found according to other lesions. Fifty-four patients (59.3%) showed ATS>3.5mm; risk factors comprised medial meniscal tear (OR=2.6, 95%CI [1.1-6.2]; p=0.03) and injury-to-MRI time>9 months (OR=9.8, 95% CI [1.1-85.2]; p=0.04). CONCLUSION: Spontaneous anterior tibial subluxation on MRI in complete ACL tear was significantly associated with medial meniscal tear and accident-to-MRI time. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Can we improve the diagnosis of spondyloarthritis in patients with uncertain diagnosis? The EchoSpA prospective multicenter French cohort.

UNLABELLED: Power Doppler ultrasound (PDUS) has proved to be a highly sensitive tool for assessing enthesitis in spondyloarthritis (SpA). In patients with a suspected SpA, diagnosis could be improved by detecting enthesitis with PDUS. OBJECTIVE: To evaluate the performance of PDUS for the diagnosis of SpA alone or combined with other clinical, laboratory and imaging findings in patients consulting for a suspected SpA. METHODS: Prospective, multicenter French cohort study (Boulogne-Billancourt, Brest, Caen, Grenoble, Marseille and Nancy). Outpatients consulting for symptoms suggestive of SpA (inflammatory back pain [IBP], arthritis or inflammatory arthralgia [IA], enthesitis or dactylitis [ED], HLA-B27 positive uveitis [B27+U], familiarity for SpA [Fam]) were recruited and followed up for at least 2 years. Sample size was set to 500 patients (for estimated prevalence of SpA of 30±5% after 2 years). At baseline, patients were submitted to standardized physical examination, pelvic X-ray, sacroiliac joints magnetic resonance imaging (MRI), HLA-B typing, and other tests judged useful for diagnosis. For each patient, a blinded PDUS examination of 14 enthesitic sites was performed at baseline and at years 1 and 2. Patients were planned to be followed during 5 years. The diagnosis of SpA ascertained by an experts' committee, blind to PDUS results, after at least 2 years of follow-up, with a revaluation of doubtful patients at 5 years will be used as gold standard for evaluating the diagnostic performance of PDUS and the best diagnostic procedure by combining PDUS, clinical symptoms and other tests. RESULTS: Between January 2005 and September 2007, 489 patients were included (96% of the target population). Nineteen patients (0.2%) retired their informed consensus or were lost to follow-up immediately after their inclusion. At baseline, mean age of the 470 remaining patients was 40 years, mean duration of symptoms was 6.1 years; 42% of them were HLA-B27+ and 63% were female. Primary inclusion criterion was IBP in 53%, IA in 27%, ED in 9%, B27+U in 8% and Fam in 4%. Follow-up is still ongoing. CONCLUSION: We have set up a unique diagnostic cohort which includes the entire spectrum of SpA manifestations. By using PDUS we expected to improve the diagnostic procedure of SpA.

Anterior cruciate ligament reconstruction with bioabsorbable polyglycolic acid interference screws: MR imaging follow-up.

PURPOSE: To examine at magnetic resonance (MR) imaging the degradation of an interference screw made of polyglycolic acid (67.5%) and trimethylene carbonate (32.5%) and compare the MR findings with the clinical evaluation results. MATERIALS AND METHODS: Clinical and MR imaging studies were performed concomitantly 6 months (in 20 patients), 1 year (in 10 patients), and 2 years (in eight patients) after surgery. Screw resorption rate, tibial tunnel appearance and contents, epiphyseal reaction, reconstructed ligament appearance, bone plug healing, joint effusion, and synovitis were evaluated. RESULTS: The screw was observed to be partially resorbed (by approximately one-third) at 6 months and totally resorbed at 1 year. Enhancement of the tunnel content, which can be linked to bone healing and screw replacement, was seen without a surrounding inflammatory reaction. Bone tunnel enlargement was observed and remained stable over time; this phenomenon has often been reported with metallic or polylactic acid interference screws and could be due to the position of the screw within the tunnel. The tissue that was seen at MR imaging to be replacing the screw was either fibrous or fatty and fibrous but never bone. CONCLUSION: Resorption of the screw does not appear to be related to clinical results.