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OBJECTIVE: Among rheumatoid arthritis (RA) patients who have had the disease for 10 years, more than half have focal erosions, and the risk of fracture is doubled. However, there is little information about the potential relationship between focal erosions and bone mineral density (BMD). The aim of this study was to determine whether lower BMD is associated with higher erosion scores among patients with RA. METHODS: We enrolled 163 postmenopausal women with RA, none of whom were taking osteoporosis medications. Patients underwent dual x-ray absorptiometry at the hip and spine and hand radiography, and completed a questionnaire. The hand radiographs were scored using the Sharp method, and the relationship between BMD and erosions was measured using Spearman's correlation coefficients and adjusted linear regression models. RESULTS: Patients had an average disease duration of 13.7 years, and almost all were taking a disease-modifying antirheumatic drug. Sixty-three percent were rheumatoid factor (RF) positive. The median modified Health Assessment Questionnaire score was 0.7, and the average Disease Activity Score in 28 joints was 3.8. The erosion score was significantly correlated with total hip BMD (r = -0.33, P < 0.0001), but not with lumbar spine BMD (r = -0.09, P = 0.27). Hip BMD was significantly lower in RF-positive patients versus RF-negative patients (P = 0.02). In multivariable models that included age, body mass index, and cumulative oral glucocorticoid dose, neither total hip BMD nor lumbar spine BMD was significantly associated with focal erosions. CONCLUSION: Our results suggest that hip BMD is associated with focal erosions among postmenopausal women with RA, but that this association disappears after multivariable adjustment. While BMD and erosions may be correlated with bone manifestations of RA, their relationship is complex and influenced by other disease-related factors. [ABSTRACT FROM AUTHOR]

BACKGROUND: Injury of a popliteal fossa artery during orthopaedic knee surgery is very rare but has serious consequences. The risk of vascular trauma during orthopaedic procedures may be increased when there is abnormal branching of the popliteal artery with an aberrant anterior tibial artery originating above the popliteus muscle and coursing between the posterior tibial cortex and ventral margin of the popliteus muscle. Preoperative identification of this anatomical variant may help avoid these injuries. HYPOTHESIS: The aberrant anterior tibial artery is present in a substantial portion of the population and can be visualized by magnetic resonance imaging. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Retrospective review of 1116 consecutive knee magnetic resonance imaging studies was performed to evaluate the prevalence of an aberrant anterior tibial artery. Images were reviewed by 3 musculoskeletal radiologists. RESULTS: The aberrant anterior tibial artery was present in 23 of 1116 extremities for a prevalence of 2.1%. The aberrant artery was most easily identified on axial and sagittal magnetic resonance imaging scans. CONCLUSION: The aberrant anterior tibial artery is a relatively common normal variant, and magnetic resonance is an excellent modality for detection of the artery close to the posterior joint capsule and tibial cortex. CLINICAL RELEVANCE: The anatomy suggests the aberrant anterior tibial artery may be at greater risk of injury in orthopaedic procedures such as high tibial osteotomy, revision total knee arthroplasty, lateral meniscal repair, posterior cruciate ligament reconstruction, and screw fixation for tibial tubercle osteotomy. Careful inspection of preoperative magnetic resonance imaging studies may alert the surgeon to the presence of this anatomical variant. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to introduce the MOCART 2.0 ankle score and evaluate its utility and reproducibility for the radiological assessment of cartilage repair tissue in the ankle joint., Methods: The MOCART 2.0 ankle score evaluates seven individual variables, including "volume fill of (osteo)chondral defect," "Integration into adjacent cartilage and bone," "surface of the repair tissue," "signal intensity of the repair tissue," "bony defect and bony overgrowth," "presence of edema-like-marrow signal," and "presence of subchondral cysts." Overall, a MOCART 2.0 ankle score between 0 and 100 points may be reached. Two independent readers assessed the 3-T MRI examinations of 48 ankles, who had undergone cartilage repair of a talar cartilage defect using the new MOCART 2.0 ankle score. One of the readers performed two readings. Intra- and interrater reliability were assessed using intraclass correlation coefficients (ICCs) for the overall MOCART 2.0 ankle score., Results: Forty-eight ankles (mean age at surgery 30.2 ± 11.2 years) were evaluated. The overall interrater (ICC = 0.75; 95%CI 0.60-0.85), as well as the intrarater (ICC = 0.83; 95%CI 0.72-0.90) reliability of the MOCART 2.0 ankle score was good. For individual variables the interrater reliability ranged from a kappa value of 0.29 (95%CI 0.01-0.57) for "surface of the repair tissue" to 0.83 (95%CI 0.71-0.95) for "presence of subchondral cysts"., Conclusions: The newly introduced MOCART 2.0 ankle score, which encompasses the distinct anatomy of the ankle joint, demonstrates good intra- and interrater reliability., Critical Relevance Statement: The newly introduced MOCART 2.0 ankle score may facilitate the standardized assessment of cartilage repair in the ankle joint and allow an objective comparison of the morphological outcome between alternative treatment options and between different studies., Key Points: This study introduces the MOCART 2.0 ankle score. The MOCART 2.0 ankle score demonstrated good intra- and interrater reliability. Standardized reporting may improve communication between radiologists and other physicians., (© 2024. The Author(s).)

Background: Meniscal tear in older adults often accompanies knee osteoarthritis and is commonly treated with arthroscopic partial meniscectomy (APM) when patients have persistent pain after a trial of physical therapy. Cross-sectional evidence suggests that synovitis is associated with baseline pain in this patient population, but little is known about the relationship between synovitis and postoperative recovery or progression of knee osteoarthritis., Purpose/hypothesis: Intra-articular extended-release triamcinolone may reduce inflammation and thereby improve outcomes and slow disease progression. This article presents the rationale behind the Corticosteroid Meniscectomy Trial (CoMeT) and describes its study design and implementation strategies., Study Design: Randomized controlled trial., Methods: CoMeT is a 2-arm, 3-center, randomized placebo-controlled trial designed to establish the clinical efficacy of extended-release triamcinolone administered via intra-articular injection immediately after APM. The primary outcome is change in Knee injury and Osteoarthritis Outcome Score Pain subscore at 3-month follow-up. Synovial biopsy, joint fluid aspirate, and urine and blood sample analyses will examine the associations between various objective measures of baseline inflammation and pre- and postoperative outcome measures and clinical responses to triamcinolone intervention. Quantitative 3-T magnetic resonance imaging will evaluate cartilage and meniscal composition and 3-dimensional bone shape to detect early joint degeneration., Results: We discuss methodologic innovations and challenges., Conclusion: To our knowledge, this is the first randomized double-blind clinical trial that will analyze the effect of extended-release triamcinolone acetonide on pain, magnetic resonance imaging measures of structural change and effusion/synovitis, soluble biomarkers, and synovial tissue transcriptomics after APM., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: All study-related activities are supported by the Arthritis Foundation, with the exception that Pacira BioSciences will provide the necessary doses of extended-release triamcinolone (Zilretta) to all 3 study sites and will support collection and analysis of biospecimens. C.S.W. has received consulting fees from Siemens Medical. K.P.S. has received consulting fees and honoraria from Flexion Therapeutics. R.W.W. has received royalties from Responsive Arthroscopy. M.H.J. has received consulting fees from Regeneron. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2023.)

Objective: To evaluate the multi-vendor multi-site reproducibility of two-dimensional (2D) multi-echo spin-echo (MESE) T 2 mapping (product sequences); and to evaluate the longitudinal reproducibility of three-dimensional (3D) magnetization-prepared angle-modulated partitioned k-space spoiled gradient echo snapshots (MAPSS) T 1ρ and T 2 mapping (research sequences), and 2D MESE T 2 mapping, separated by 6 months, in a multi-vendor multi-site setting., Methods: Phantoms and volunteers (n = 5 from each site, n = 20 in total) were scanned on four 3 T magnetic resonance (MR) systems from four sites and three vendors (Siemens, General Electric, and Phillips). Two traveling volunteers (3 knees) scanned at all 4 sites at baseline and 6-month follow-up. Data was transferred to one site for centralized processing. Coefficients of variation (CVs) were calculated to evaluate reproducibility., Results: For baseline 2D MESE T 2 measures, average CV were 0.37-2.45% (intra-site) and 5.96% (inter-site) for phantoms, and 3.15-8.49% (intra-site) and 14.16% (inter-site) for volunteers. For longitudinal phantom data, intra-site CVs were 1.42-3.48% for 3D MAPSS T 1ρ , 1.77-3.56% for 3D MAPSS T 2 , and 1.02-2.54% for 2D MESE T 2 . For the longitudinal volunteer data, the intra-site CVs were 2.60-4.86% for 3D MAPSS T 1ρ , 3.33-7.25% for 3D MAPSS T 2 , and 3.11-8.77% for 2D MESE T 2 ., Conclusion: This study demonstrated excellent intra-site reproducibility of 2D MESE T 2 imaging, while its inter-site variation was slightly higher than 3D MAPSS T 2 imaging (10.06% as previously reported). This study also showed excellent reproducibility of longitudinal T 1ρ and T 2 cartilage quantification, in a multi-vendor multi-site setting for both product 2D MESE T 2 and 3D MAPSS T 1p /T 2 research sequences., (Copyright © 2022 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Objective: To describe the protocol of a multi-vendor, multi-site quantitative MRI study for knee post-traumatic osteoarthritis (PTOA), and to present preliminary results of cartilage degeneration using MR T 1ρ and T 2 imaging 10 years after anterior cruciate ligament reconstruction (ACLR)., Design: This study involves three sites and two MR platforms. The patients are from a nested cohort (termed as Onsite cohort) within the Multicenter Orthopaedic Outcomes Network (MOON) cohort 10 years after ACLR. Phantoms and controls were scanned for evaluating reproducibility. Cartilage was automatically segmented, and T 1ρ and T 2 were compared between operated, contralateral, and control knees., Results: Sixty-eight ACL-reconstructed patients and 20 healthy controls were included. In phantoms, the intra-site coefficients of variation (CVs) of repeated scans ranged 1.8-2.1% for T 1ρ and 1.3-1.7% for T 2 . The inter-site CVs ranged 1.6-2.1% for T 1ρ and 1.1-1.4% for T 2 . In human subjects, the intra-site scan/rescan CVs ranged 2.2-3.5% for T 1ρ and 2.6-4.9% for T 2 for the six major compartments. In patients, operated knees showed significantly higher T 1ρ and T 2 values mainly in medial femoral condyle, medial tibia and trochlear cartilage compared with contralateral knees, and showed significantly higer T 1ρ  and T 2 values in all six compartments compared to healthy control knees. The patient contralateral knees showed higher T 1ρ and T 2 values mainly in the lateral femoral condyle, lateral tibia, trochlear, and patellar cartilage compared to healthy control knees., Conclusion: A platform and workflow with rigorous quality control has been established for a multi-vendor multi-site quantitative MRI study in evaluating PTOA 10 years after ACLR. Our preliminary report suggests significant cartilage matrix changes in both operated and contralateral knees compared with healthy control knees., Competing Interests: Conflict of interest The authors have no conflicts of interest to disclose., (Copyright © 2022 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Background: Magnetic resonance imaging (MRI)-based rotator cuff assessment is often qualitative and subjective; few studies have tried to validate such preoperative assessments. This study investigates relationships of preoperative MRI assessments made by conventional approaches to intraoperative findings of tear type, location, and size or MRI-assessed muscle occupation ratio., Methods: Intraoperatively, surgeons assessed tear type, location, anterior-posterior (AP) width, and medial-lateral length in 102 rotator cuff repair patients. Two musculoskeletal radiologists independently assessed the preoperative MRI scans for these same parameters and supraspinatus muscle atrophy by both Warner classification and quantitative occupation ratio. Exact agreement proportions, kappa statistics, and correlation coefficients were used to quantify agreement relationships., Results: Agreement between MRI readers' and surgeons' observations of tear status averaged 93% with κ = 0.38, and that of tear location averaged 77% with κ = 0.50. Concordance correlations of MRI and intraoperative measures of anterior-posterior and medial-lateral tear length averaged 0.59 and 0.56 across readers, respectively. Despite excellent interrater agreement on Warner classification (exact agreement proportion 0.91) and occupation ratio (concordance correlation 0.93) separately, correlations between these 2 measures were -0.54 and -0.64 for the 2 readers, respectively. Patients with Warner grade 0 had occupation ratios ranging from 0.5 to 1.5., Conclusion: Correlations of preoperative MRI tear dimensions and muscle atrophy assessed by conventional approaches with intraoperatively measured tear dimensions and quantitative occupation ratio, respectively, were only fair. Since tear size and muscle atrophy are known strong predictors of outcomes following rotator cuff repair that may influence treatment decisions, surgeons need to be aware of the limitations of MRI methods. Continued development and validation of quantitative preoperative imaging methods to accurately assess these parameters are needed to improve surgical planning and prognosis., (© 2022 The Author(s).)

Background: This study aimed to build a deep learning model to automatically segment heterogeneous clinical MRI scans by optimizing a pre-trained model built from a homogeneous research dataset with transfer learning., Methods: Conditional generative adversarial networks pretrained on the Osteoarthritis Initiative MR images was transferred to 30 sets of heterogenous MR images collected from clinical routines. Two trained radiologists manually segmented the 30 sets of clinical MR images for model training, validation and test. The model performance was compared to models trained from scratch with different datasets, as well as two radiologists. A 5-fold cross validation was performed., Results: The transfer learning model obtained an overall averaged Dice coefficient of 0.819, an averaged 95 percentile Hausdorff distance of 1.463 mm, and an averaged average symmetric surface distance of 0.350 mm on the 5 random holdout test sets. A 5-fold cross validation had a mean Dice coefficient of 0.801, mean 95 percentile Hausdorff distance of 1.746 mm, and mean average symmetric surface distance of 0.364 mm. It outperformed other models and performed similarly as the radiologists., Conclusions: A transfer learning model was able to automatically segment knee cartilage, with performance comparable to human, using heterogeneous clinical MR images with a small training data size. In addition, the model proved robust when tested through cross validation and on images from a different vendor. We found it feasible to perform fully automated cartilage segmentation of clinical knee MR images, which would facilitate the clinical application of quantitative MRI techniques and other prediction models for improved patient treatment planning., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-21-459/coif). XL reports support from NIH/NIAMS R01AR075422 and R01AR077452. NS reports support from NIH R01-AR073512. The other authors have no conflicts of interest to declare., (2022 Quantitative Imaging in Medicine and Surgery. All rights reserved.)

Objective: The study was performed to evaluate cartilage within the knee following a first-time patellar dislocation, using elevated MRI-based T1ρ relaxation times as an indicator of low proteoglycan concentration. The hypothesis is that MRI-based T1ρ relaxation times for patellofemoral and tibiofemoral cartilage are significantly longer for knees being treated for patellar dislocation than for healthy control knees., Design: Twenty-one subjects being treated for a first-time, unilateral dislocation of the patella and 16 healthy controls participated in MRI-based T1ρ relaxation time mapping. Mean relaxation times were quantified for patellofemoral and tibiofemoral regions for injured knees, the contralateral knees, and healthy controls. T1ρ values for each region were compared between the 3 groups with generalized estimating equations. Linear regressions were also performed to correlate T1ρ relaxation times with time from injury., Results: The knees with a disloction had longer T1ρ relaxation times than the contralateral knees and control group at the medial patella and longer relaxation times than the control group at the lateral tibia ( P < 0.05). T1ρ relaxation times at the medial patella also decreased with time from injury (r 2 = 0.21, P = 0.037)., Conclusions: Compositional changes to cartilage on the medial patella are related to traumatic impact during a dislocation. Potential exists for cartilage properties at the medial patella to improve with time. Cartilage degradation at the lateral tibia is not directly related to traumatic impact. The current baseline data are a starting point to characterize the pathway from a first-time dislocation to progressive cartilage degradation and osteoarthritis.

Background: BEAR (bridge-enhanced anterior cruciate ligament [ACL] restoration), a paradigm-shifting technology to heal midsubstance ACL tears, has been demonstrated to be effective in a single-center 2:1 randomized controlled trial (RCT) versus hamstring ACL reconstruction. Widespread dissemination of BEAR into clinical practice should also be informed by a multicenter RCT to demonstrate exportability and compare efficacy with bone--patellar tendon-bone (BPTB) ACL reconstruction, another clinically standard treatment., Purpose: To present the design and initial preparation of a multicenter RCT of BEAR versus BPTB ACL reconstruction (the BEAR: Multicenter Orthopaedic Outcomes Network [BEAR-MOON] trial). Design and analytic issues in planning the complex BEAR-MOON trial, involving the US National Institute of Arthritis and Musculoskeletal and Skin Diseases, the US Food and Drug Administration, the BEAR implant manufacturer, a data and safety monitoring board, and institutional review boards, can usefully inform both clinicians on the trial's strengths and limitations and future investigators on planning of complex orthopaedic studies., Study Design: Clinical trial., Methods: We describe the distinctive clinical, methodological, and operational challenges of comparing the innovative BEAR procedure with the well-established BPTB operation, and we outline the clinical motivation, experimental setting, study design, surgical challenges, rehabilitation, outcome measures, and planned analysis of the BEAR-MOON trial., Results: BEAR-MOON is a 6-center, 12-surgeon, 200-patient randomized, partially blinded, noninferiority RCT comparing BEAR with BPTB ACL reconstruction for treating first-time midsubstance ACL tears. Noninferiority of BEAR relative to BPTB will be claimed if the total score on the International Knee Documentation Committee (IKDC) subjective knee evaluation form and the knee arthrometer 30-lb (13.61-kg) side-to-side laxity difference are both within respective margins of 16 points for the IKDC and 2.5 mm for knee laxity., Conclusion: Major issues include patient selection, need for intraoperative randomization and treatment-specific postoperative physical therapy regimens (because of fundamental differences in surgical technique, initial stability construct, and healing), and choice of noninferiority margins for short-term efficacy outcomes of a novel intervention with evident short-term advantages and theoretical, but unverified, long-term benefits on other dimensions., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: see Supplemental Material for details. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2022.)

Background: The prevalence of patellofemoral joint (PFJ) osteoarthritis ranges from 8% to 47% at 7 to 10 years after anterior cruciate ligament reconstruction (ACLR) using bone-patellar tendon-bone (BTB) autograft. In performing BTB ACLR, some hypothesize that either trauma caused by harvest of the BTB autograft or altered biomechanics contributes to PFJ posttraumatic osteoarthritis., Purpose/hypothesis: To determine whether knees with ACLR using a BTB autograft show early signs of posttraumatic osteoarthritis as compared with the contralateral uninjured knee 2 years after ACLR. We hypothesized that a BTB autograft will not increase the prevalence of PFJ osteoarthritis., Study Design: Cohort study; Level of evidence, 3., Methods: Bilateral knee 3-T magnetic resonance imaging (MRI) scans were collected in 57 patients (mean age, 20.3 years; 28 men) from a single site at a minimum of 2 years after ACLR. Structural MRI assessment of the knees was performed using the MRI Osteoarthritis Knee Score semiquantitative scoring system by a board-certified musculoskeletal radiologist. The presence of cartilage defects in the patellofemoral compartment was compared between the reconstructed and contralateral uninjured knees using logistic regression analyses., Results: There were no significant differences in the prevalence of cartilage defects (full thickness or any thickness) in the PFJ between the BTB ACLR knees and the contralateral control knees: 38.6% of BTB ACLR knees had PFJ cartilage defects versus 31.6% of contralateral control knees ( P > .391). The 95% CI for the difference between these groups was -9.0% to 23.0%., Conclusion: When comparing BTB ACLR knees with the uninjured contralateral knees in the study patients, we failed to observe statistically significant differences in the prevalence of PFJ cartilage lesions of full thickness or any thickness. These results should be used in shared decision-making with athletes when choosing the appropriate autograft during reconstruction. Our wide 95% CIs secondary to a smaller sample size demonstrate a need for larger studies in this area to more accurately describe the difference between the operative and contralateral knees., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: Research reported in this publication was partially supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (award number R01AR053684 to K.P.S. and award number K23AR066133 to M.H.J.). This study also utilized resources funded by the Clinical and Translational Science Awards Program (No. UL1 TR002243). C.S.W. has received consulting fees from Aastrom Biosciences (disputed). D.C.F. has received research support from Aesculap, Arthrex, Conmed/MTF, DePuy, KCRN, Moximed, Smith & Nephew, Vericel, and Zimmer Biomet; educational payments from CDC Medical and Zimmer Biomet; consulting fees from Aastrom Biosciences, Ceterix, DePuy/Medical Device Business Services, Hyalex, KCRN, Linvatec, Moximed, Smith & Nephew, Vericel, and Zimmer Biomet; nonconsulting fees from Smith & Nephew and Vericel; faculty/speaker fees from Linvatec; and honoraria from Vericel. M.H.J. is a member of the scientific advisory board for Samumed. K.P.S. has received research support from DonJoy Orthopaedics and Smith & Nephew Endoscopy and consulting fees from Flexion Therapeutics, the National Football League, and Novopeds. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

Objective: To develop 3D T 1ρ and T 2 imaging based on the same sequence structure on MR systems from multiple vendors, and to evaluate intra-site repeatability and inter-site inter-vendor reproducibility of T 1ρ and T 2 measurements of knee cartilage., Methods: 3D magnetization-prepared angle-modulated partitioned k-space spoiled gradient echo snapshots (3D MAPSS) were implemented on MR systems from Siemens, GE and Philips. Phantom and human subject data were collected at four sites using 3T MR systems from the three vendors with harmonized protocols. Phantom data were collected by means of different positioning of the coil. Volunteers were scanned and rescanned after repositioning. Two traveling volunteers were scanned at all sites. Data were transferred to one site for centralized processing., Results: Intra-site average coefficient of variations (CVs) ranged from 1.09% to 3.05% for T 1ρ and 1.78-3.30% for T 2 in phantoms, and 1.60-3.93% for T 1ρ and 1.44-4.08% for T 2 in volunteers. Inter-site average CVs were 5.23% and 6.45% for MAPSS T 1ρ and T 2 , respectively in phantoms, and 8.14% and 10.06% for MAPSS T 1ρ and T 2 , respectively, In volunteers., Conclusion: This study showed promising results of multi-site, multi-vendor reproducibility of T 1ρ and T 2 values in knee cartilage. These quantitative measures may be applied in large-scale multi-site, multi-vendor trials with controlled sequence structure and scan parameters and centralized data processing., (Copyright © 2020 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Background: Little is known regarding the optimal treatment for displaced, purely chondral fragments in the knee., Purpose: To report the clinical and radiographic outcomes of chondral fragment fixation in adolescents through use of autologous bone pegs., Study Design: Case series; Level of evidence, 4., Methods: This retrospective, single-center study evaluated 6 patients (mean age, 12.9 years) who underwent fixation of chondral fragments (no visualized bone attached) using autologous bone pegs (mean postoperative follow-up, 5.2 years; range, 1.4-10.9 years). The causes were trauma (n = 5) and osteochondritis dissecans (n = 1). Lesions were located in the trochlear groove (lateral, n = 3; medial, n = 2) or posterior part of the lateral femoral condyle (n = 1). The mean lesion size was 3.8 cm 2 (range, 0.8-9.0 cm 2 ). Patients were evaluated via physical examination and magnetic resonance imaging (MRI) using magnetic resonance observation of cartilage repair tissue scores., Results: In total, 5 patients successfully returned to sports without restrictions at a mean of 7 months (range, 6-8 months) postoperatively. At the latest follow-up, these 5 patients had full range of motion and no joint effusion. The mean magnetic resonance observation of cartilage repair tissue score was 85 (range, 70-95) at a mean duration of 3 years (range, 1-5 years). One patient experienced failure at 1.3 years postoperatively after a traumatic injury and subsequently underwent removal of the fixed fragment and a drilling procedure., Conclusion: In most adolescents, fixation of chondral fragments with no visualized bony portion using autologous bone pegs provided a satisfactory success rate and good healing of cartilage tissue confirmed on MRI scans., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: C.S.W. has received consulting fees and teaching fees from Aastrom Biosciences (contested by the author). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2020.)

Background: MRI acceleration using deep learning (DL) convolutional neural networks (CNNs) is a novel technique with great promise. Increasing the number of convolutional layers may allow for more accurate image reconstruction. Studies on evaluating the diagnostic interchangeability of DL reconstructed knee magnetic resonance (MR) images are scarce. The purpose of this study was to develop a deep CNN (DCNN) with an optimal number of layers for accelerating knee magnetic resonance imaging (MRI) acquisition by 6-fold and to test the diagnostic interchangeability and image quality of nonaccelerated images versus images reconstructed with a 15-layer DCNN or 3-layer CNN., Methods: For the feasibility portion of this study, 10 patients were randomly selected from the Osteoarthritis Initiative (OAI) cohort. For the interchangeability portion of the study, 40 patients were randomly selected from the OAI cohort. Three readers assessed meniscal and anterior cruciate ligament (ACL) tears and cartilage defects using DCNN, CNN, and nonaccelerated images. Image quality was subjectively graded as nondiagnostic, poor, acceptable, or excellent. Interchangeability was tested by comparing the frequency of agreement when readers used both accelerated and nonaccelerated images to frequency of agreement when readers only used nonaccelerated images. A noninferiority margin of 0.10 was used to ensure type I error ≤5% and power ≥80%. A logistic regression model using generalized estimating equations was used to compare proportions; 95% confidence intervals (CIs) were constructed., Results: DCNN and CNN images were interchangeable with nonaccelerated images for all structures, with excess disagreement values ranging from -2.5% [95% CI: (-6.1, 1.1)] to 3.0% [95% CI: (-0.1, 6.1)]. The quality of DCNN images was graded higher than that of CNN images but less than that of nonaccelerated images [excellent/acceptable quality: DCNN, 95% of cases (114/120); CNN, 60% (72/120); nonaccelerated, 97.5% (117/120)]., Conclusions: Six-fold accelerated knee images reconstructed with a DL technique are diagnostically interchangeable with nonaccelerated images and have acceptable image quality when using a 15-layer CNN., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/qims-20-664). DL serves as an unpaid editorial board member of Quantitative Imaging in Medicine and Surgery. NS reports grants from Society of Skeletal Radiology, during the conduct of the study; CW reports grants from Society of Skeletal Radiology, during the conduct of the study; NO reports other from Quantitative Imaging Biomarker Alliance (QIBA), outside the submitted work. The other authors have no conflicts of interest to declare., (2020 Quantitative Imaging in Medicine and Surgery. All rights reserved.)

Background: Symptomatic osteochondral defects are difficult to manage, especially in patients with deep (>8-10 mm) empty defects. The restoration of articular congruence is crucial to avoid the progression to osteoarthritis (OA)., Purpose: To describe the autologous chondrocyte implantation (ACI) "segmental-sandwich" technique for restoration of the osteochondral unit and to evaluate midterm outcomes in patients treated with this procedure. Correlations between magnetic resonance imaging (MRI) and radiographic findings with outcomes were assessed., Study Design: Case series; Level of evidence, 4., Methods: Outcomes were evaluated for a consecutive cohort of 15 patients with symptomatic deep (>8 mm) osteochondral lesions who underwent autologous bone grafting plus the ACI segmental-sandwich technique performed by a single surgeon between 2003 and 2011. Patients with a minimum 2-year follow-up were included. All patients completed validated clinical outcome scales and a patient satisfaction survey. The Kellgren-Lawrence (K-L) grade was assessed for the progression to OA. The repair site was evaluated with the MOCART (magnetic resonance observation of cartilage repair tissue) score. Filling and tissue characteristics of the bone defect were analyzed with MRI., Results: All patients (mean age at surgery, 31.0 ± 9.1 years) were available for follow-up (mean follow-up, 7.8 ± 3.0 years; range, 2-15 years). The mean chondral lesion size was 6.0 ± 3.5 cm 2 (range, 1.5-13.5 cm 2 ), with a mean bone defect area of 1.7 cm 2 (27%-40% of overall surface area treated by ACI) and depth of 1.0 cm. All patients had successful clinical outcomes, and all functional scores improved significantly ( P < .05). Patients reported a very high satisfaction rate (93%). The K-L grade demonstrated no significant progression to OA over a mean follow-up of 4.7 years. For 12 patients with MRI results available, the mean MOCART score at a mean of 3.3 years was 64.2 ± 19.9, with complete or near-complete (≥75% of defect volume) chondral defect filling (83%) and complete integration to adjacent cartilage (83%). Bone defects were completely filled in 83% of patients., Conclusion: The ACI segmental-sandwich technique provides significant functional improvements at midterm follow-up and excellent survival rates. This unique treatment allows for the resurfacing of cartilage defects and the repair of underlying segmental bone lesions., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: C.S.W. has received consulting fees and educational support from Aastrom Biosciences (contested) and has stock/stock options in Pfizer. T.M. has received consulting fees from Aastrom Biosciences, Conformis, and Vericel and receives royalties from Conformis. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Objective: To identify risk factors for radiographic signs of post-traumatic osteoarthritis (OA) 2-3 years after anterior cruciate ligament (ACL) reconstruction through multivariable analysis of minimum joint space width (mJSW) differences in a specially designed nested cohort., Methods: A nested cohort within the Multicenter Orthopaedic Outcomes Network (MOON) cohort included 262 patients (148 females, average age 20) injured in sport who underwent ACL reconstruction in a previously uninjured knee, were 35 or younger, and did not have ACL revision or contralateral knee surgery. mJSW on semi-flexed radiographs was measured in the medial compartment using a validated computerized method. A multivariable generalized linear model was constructed to assess mJSW difference between the ACL reconstructed and contralateral control knees while adjusting for potential confounding factors., Results: Unexpectedly, we found the mean mJSW was 0.35 mm wider in ACL reconstructed than in control knees (5.06 mm (95% CI 4.96-5.15 mm) vs 4.71 mm (95% CI 4.62-4.80 mm), P < 0.001). However, ACL reconstructed knees with meniscectomy had narrower mJSW compared to contralateral normal knees by 0.64 mm (95% C.I. 0.38-0.90 mm) (P < 0.001). Age (P < 0.001) and meniscus repair (P = 0.001) were also significantly associated with mJSW difference., Conclusion: Semi-flexed radiographs can detect differences in mJSW between ACL reconstructed and contralateral normal knees 2-3 years following ACL reconstruction, and the unexpected wider mJSW in ACL reconstructed knees may represent the earliest manifestation of post-traumatic osteoarthritis and warrants further study., (Copyright © 2015. Published by Elsevier Ltd.)

Objective: Contrast-enhanced magnetic resonance (MR) imaging methods have been proposed for non-invasive evaluation of osteoarthritis (OA). We measured cell toxicities of cartilage-targeted low-generation dendrimer-linked nitroxide MR contrast agents and gadopentetate dimeglumine (Gd-DTPA) on cultured chondrocytes., Design: A long-term Swarm rat chondrosarcoma chondrocyte-like cell line was exposed for 48-h to different salts (citrate, maleate, tartrate) and concentrations of generation one or two diaminobutyl-linked nitroxides (DAB4-DLN or DAB8-DLN), Gd-DTPA, or staurosporine (positive control). Impact on microscopic cell appearance, MTT spectrophotometric assays of metabolic activity, and quantitative PicoGreen assays of DNA content (cell proliferation) were measured and compared to untreated cultures., Results: Chondrocyte cultures treated with up to 7.5 mM Gd-DTPA for 48-h had no statistical differences in DNA content or MTT reaction compared to untreated cultures. At all doses, DAB4-DLN citrate treated cultures had results similar to untreated and Gd-DTPA-treated cultures. At doses >1 mM, DAB4-DLN citrate treated cultures showed statistically greater DNA and MTT reaction than maleate and tartrate DAB4-DLN salts. Cultures exposed to 5 mM or 7.5 mM DAB8-DLN citrate exhibited rounded cells, poor cell proliferation, and barely detectable MTT reaction. Treatment with 0.1 μM staurosporine caused chondrocyte death., Conclusion: Long-term exposure, greater than clinically expected, to either DAB4-DLN citrate or Gd-DTPA had no detectable toxicity with results equivalent to untreated cultures. DAB4-DLN citrate was more biocompatible than either the maleate or tartrate salts. Cells exposed for 48-h to 5 mM or 7.5 mM DAB8-DLN salts demonstrated significant cell toxicity. Further evaluation of DAB8-DLN with clinically appropriate exposure times is required to determine the maximum useful concentration., (Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Objective: To evaluate if quantitative joint space width (JSW) measurements from radiographs correlate with 4-year Knee injury and Osteoarthritis Outcome Scores (KOOS) and clinical performance measures., Method: The study group consisted of 942 patients with symptomatic knee osteoarthritis (OA). 4-year outcomes for six measures (KOOS Pain, Symptom, Quality of Life, and Function scores, 20-m walk pace, and chair stand time) were used to create six multiple linear regression models. Primary predictors were baseline minimum JSW and 4-year change in JSW measured from fixed flexion radiographs. Age, gender, body mass index (BMI), race, knee alignment, and baseline measures of the outcomes of interest were covariates., Results: Lower baseline minimum JSW and a greater decrease in 4-year JSW significantly correlated with worse 4-year KOOS Pain, Symptom, and Quality of Life. With all other factors constant, a 4.1, 4.8, and 5.6 mm lower baseline JSW correlated with a clinically significant eight-point drop in 4-year KOOS Pain, Symptom, and Quality of Life scores respectively. Additionally, a 3.5, 3.1, and 4.0 mm loss of JSW over 4 years correlated with a clinically significant eight-point drop in 4-year KOOS Pain, Symptom, and Quality of Life scores respectively., Conclusions: Our results indicate quantitative radiographic JSW measurements correlate with 4-year clinical outcomes. Since patients with narrower JSW at the onset of study had lower KOOS scores at 4 years even after controlling for 4-year change in JSW and baseline KOOS scores, clinical outcomes in knee OA may be predetermined once the disease process begins. These findings suggest early treatment with disease modifying therapies may be necessary to influence outcomes., (© 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Articular cartilage lesions are a common pathology of the knee joint, and many patients may benefit from cartilage repair surgeries that offer the chance to avoid the development of osteoarthritis or delay its progression. Cartilage repair surgery, no matter the technique, requires a noninvasive, standardized, and high-quality longitudinal method to assess the structure of the repair tissue. This goal is best fulfilled by magnetic resonance imaging (MRI). The present article provides an overview of the current state of the art of MRI of cartilage repair. In the first 2 sections, preclinical and clinical MRI of cartilage repair tissue are described with a focus on morphological depiction of cartilage and the use of functional (biochemical) MR methodologies for the visualization of the ultrastructure of cartilage repair. In the third section, a short overview is provided on the regulatory issues of the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) regarding MR follow-up studies of patients after cartilage repair surgeries.

Introduction: Protein and electrolyte concentration of synovial fluid (SF) varies with the type of underlying arthritis. These characteristics can be utilized by magnetic resonance technology to provide a potentially significant diagnostic modality through quantitative assessments of inherent water relaxation rates and their response to contrast agents., Methods: We evaluated the effect of a classic "in vitro" contrast agent, the Mn ion, and a common "in vivo" gadolinium based contrast agent, gadopentetate dimeglumine, on the water relaxation times of solutions with biochemical compositions simulating different types of arthritis along with similar studies of SF obtained from patients., Results: The results demonstrate how protein and electrolyte concentrations play a significant role in the response of water relaxation to the Mn ion but much less so to chelated gadolinium contrast agents used clinically., Discussion: A major challenge remains to develop paramagnetic agents with less toxicity than the Mn ion but with similar properties that can then serve as a tool to determine protein concentrations through imaging and thereby assist in the diagnosis of inflammatory arthrides and evaluation of therapeutic regimens., (Copyright 2010 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Objective: Magnetic resonance (MR) imaging with contrast media has shown promise for articular cartilage assessment. Dendrimer-linked nitroxides, a new family of MR contrast agents targeted to glycosaminoglycan, may improve cartilage evaluation. This study is designed to determine the ability of dendrimer-linked nitroxides to enhance articular cartilage and measure the intra-articular life-time of these agents., Design: Cartilage T(1) was evaluated using immature bovine patella in solutions of five different dendrimer-linked nitroxides, saline or Gd-DTPA at 1.5T. The "relaxivity per dose" (change in cartilage 1/T(1) produced by a given concentration of agent) was calculated. The half-life of joint fluid enhancement was measured at 2T after solutions of three dendrimer-linked nitroxides, Gd-DTPA, and saline were injected into rabbit stifle joints. Twenty-four hours after injection, the joints were examined grossly and by histology for toxicity., Results: All but the largest dendrimer-linked nitroxide were able to intensely enhance articular cartilage on MR. Relaxivity per dose measurements were between 3.5 and 68 times greater than Gd-DTPA. The largest nitroxide appeared to be excluded from articular cartilage. Intra-articular half-lives of the dendrimer-linked nitroxides were sufficiently long (160-208 min) for in vivo MR imaging to be performed. Histological assessments of joints showed minimal synovial inflammatory and necrosis scores 1 day post-injection that were similar for all agents, including Gd-DTPA., Conclusion: Dendrimer-linked nitroxides strongly enhance cartilage and are promising as articular cartilage-specific MR contrast agents. The intra-articular life-time is sufficient for imaging studies and, in initial evaluation, the agents exhibit minimal toxicity in rabbit joints.

Objective: To determine the prevalence of labral tears and cartilage lesions in patients with mechanical symptoms of the hip using magnetic resonance (MR) arthrography., Methods: A total of 100 patients with mechanical symptoms of the hip such as pain, clicking, locking and giving way underwent MR arthrography of the hip to rule out a labral tear. Hip joints were evaluated for labral alterations, bone marrow edema (BME), and other pathology using a novel semi-quantitative scoring system. Cartilage changes were graded separately for the acetabulum and femoral head in the anterior, posterior, central, medial, and lateral hip joint regions (10 locations) on a 6-point scale: 0=normal; 1=signal heterogeneity; 2=fissuring, 3=thinning <50% of the normal thickness; 4=thinning >50% of the normal thickness; 5=full thickness cartilage loss. Labral tears were categorized into normal, intrasubstance degeneration, simple tear or complex tear with two or more tear regions. Statistical methods were contingency tables, Fisher's exact test for discrete outcomes (based on grade scores), Spearman's rank correlation (r) and t tests for continuous outcomes, using pooled and stratified analyses., Results: On MR arthrography, labral tears were found in 66 patients (66% prevalence) with 13 having more than one location involved. Locations were 19 lateral (13 simple, six complex), 54 anterior (39 simple, 15 complex), eight posterior (six simple, two complex). Cartilage lesions were found in 76 patients (76% prevalence) with 53 demonstrating involvement of more than one compartment. The most common finding was cartilage thinning <50% in 99 regions in 44 patients. Cartilage thinning >50% was shown in 34 patients in 67 areas. When we correlated the grade of cartilage abnormality with the grade of labral tear, we found a statistically significant correlation (r=0.29; P< or =0.01). The size of cartilage abnormality was correlated with the grade of labral tear in the lateral acetabulum (r=0.38; P<0.001), anterior acetabulum (r=0.22; P< or =0.002), and lateral femoral head (r=0.29; P< or =0.004). The grade of cartilage loss was correlated with the grade of BME (r=0.44; P< or =0.001)., Conclusion: Labral tears and cartilage loss are common in patients with mechanical symptoms in the hip. Cartilage loss, labral tears and BME appear interrelated and may represent important risk factors that may affect the development and progression of osteoarthritis in the hip joint.

The objective of the present study was to test the hypothesis that experts recognize repair of erosions and, if so, to determine which, if any, morphologic features permitted them to recognize the repair. We also tested whether scoring by a standard method detected repair. Seven experienced readers of radiographs in rheumatoid arthritis were presented with 64 sets of single joints-of-interest at two time points, randomized and blinded for the correct sequence. The readers assessed which joint was better, and recorded whether any of six specific features were seen. Two independent readers, experienced in scoring by the van der Heijde-modified Sharp method who were not on the expert panel, then scored the complete films that included the joint-of-interest. The panel agreed very well on which of two joints was better, and, even though they did not know the true sequence, the panel accurately assigned a sequence slightly better than chance alone (58%) but worse than their agreement on which image was 'better or worse' (78%). The readers therefore indirectly assigned repair by choosing the second film as the best. Putative repair features were seen in cases of both repair and progression, and were not discriminatory. Similar results were obtained when the experts were presented with the entire hand or foot containing the joint-of-interest. In the third repair exercise, two independent readers who scored whole hands and feet using a standard method found a mean negative score in 22/60 joints-of-interest. All 22 joints were also scored as repair by the panel. Repair was detected reliably by a majority of the panel on viewing paired images based on a better/worse decision and assigning sequence in a set of images that were blinded for sequence by an independent project manager. In this test set of images, repair was manifested by a reduction in the size of erosion in many cases. Size was one feature that aided the experts to detect repair but cannot be the only one; the experts had to find other features to determine whether a smaller erosion was the first in a sequence of radiographs in a patient with progressive damage or was the second film in a patient exhibiting repair. The change in size of erosion was also picked up by independent readers applying the van der Heijde-modified Sharp scoring method and was reflected in their scores.

Objective: Magnetic resonance imaging (MRI) of articular cartilage has evolved to be an important tool in research on cartilage (patho)physiology and osteoarthritis (OA). MRI provides a wealth of novel and quantitative information, but there exists no commonly accepted terminology for reporting these metrics. The objective of this initiative was to propose a nomenclature for definitions and names to be used in scientific communications and to give recommendations as to which minimal methodological information should be provided when reporting MRI-based measures of articular cartilage in OA., Methods: An international group of experts with direct experience in MRI measurement of cartilage morphology or composition reviewed the existing literature. Through an iterative process that included a meeting with a larger group of scientists and clinicians (December 2nd, 2004, Chicago, IL, USA), they discussed, refined, and proposed a nomenclature for MRI-based measures of articular cartilage in OA., Results: The group proposes a nomenclature that describes: (1) the anatomical location and (2) the structural feature being measured, each name consisting of a metric variable combined with a tissue label. In addition, the group recommends minimal methodological information that should be described., Conclusions: Utilization of this nomenclature should facilitate communication within the scientific community. Further, the uniform adoption of comprehensive nomenclature to describe quantitative MRI- features of articular cartilage should strengthen epidemiological, clinical, and pharmacological studies in OA.

Rationale and Objectives: Technium-99m methylene diphosphonate (99mTc-MDP) bone scintigraphy and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) are useful imaging modalities to detect skeletal metastases. Several other conditions such as infection, fractures, and arthritis can cause false-positive results with either modality. However, PET is felt to be more specific than bone scintigraphy for malignancy. Our objective was to investigate the value of PET scan compared with bone scintigraphy for directing biopsies in patients with suspected metastatic bone lesions., Materials and Methods: Retrospective case series of subjects with undergoing skeletal biopsy of suspected metastases detected by 99mTc-MDP scintigraphy or 18F-FDG PET scan. Reference standards were pathologic reports and follow-up for 6 months. The diagnostic test performance measures of true positive (TP), false positive (FP), and positive predictive value (PPV) were calculated for each group. The PPV with 95% confidence intervals (CI) was compared using the Fisher exact test., Results: There were a total of 68 subjects. PET-directed skeletal biopsies (n = 39) showed 35 TP, 4 FP, and an 89.7% PPV (95% CI: 75.7-97.1%). Bone scintigraphy directed biopsies (n = 29) had 21 TP, 8 FP, and 72.4 % PPV (95% CI: 52.7-82.7%). The PPV was not significantly different between the groups (P = .10)., Conclusion: This study supports that PET can be used to effectively direct bone biopsies to confirm metastatic neoplasm and suggests that PET may provide incremental improvement to diagnostic yield over bone scintigraphy. The role of PET compared with bone scintigraphy for directing skeletal biopsies warrants further verification.