Magnetic resonance imaging-based semiquantitative and quantitative assessment in osteoarthritis

A Systemic Review on Nutraceutical Supplements used in the Management of Osteoarthritis

Osteoarthritis (OA) is a progressive degenerative joint disease. It basically impairs the structural integrity of articulate cartilage and imbalances the catabolic and anabolic signals in the joint. A degenerative disease is characterized by swelling, pain, and joint stiffness. The treatment and management of osteoarthritis are based on analgesic and anti-inflammatory agents, whereas the exact cause of OA is not known yet. The negative effects of synthetic medications have led to a daily rise in the usage of nutraceuticals and dietary supplements. Clinicians are aware of these treatments, and they also recommend nutraceuticals in addition to the currently preferred therapy. Many in-vitro and in-vivo experiments have been performed in past years to evaluate the function of these on osteoarthritis. The collection of articles was published on search engines like PubMed, Scopus, Google Scholar, ResearchGate, and ScienceDirect. The evaluation covers every potential nutraceutical utilized in osteoarthritis, together with its supporting data and mode of action. The present review discusses nutraceuticals, including devil's claw, vitamin D, boswellic acid, capsaicin, ginger, curcumin, krill oil, ginger, and avocado/soybean unsaponifiable.

Meniscal degeneration is prognostic of destabilzing meniscal tear and accelerated knee osteoarthritis: Data from the Osteoarthritis Initiative

The objective of this study was to assess the prognostic potential of magnetic resonance (MR)-detected meniscal degeneration in relation to incident destabilizing meniscal tears (radial, complex, root, or macerated) or accelerated knee osteoarthritis (AKOA). We used existing MR data from a case-control study of three groups from the Osteoarthritis Initiative without radiographic KOA at baseline: AKOA, typical KOA, and no KOA. From these groups, we included people without medial and lateral meniscal tear at baseline (n = 226) and 48-month meniscal data (n = 221). Intermediate-weighted fat-suppressed MR images annually from baseline to the 48-month visit were graded using a semiquantitative meniscal tear classification criterion. Incident destabilizing meniscal tear was defined as progressing from an intact meniscus to a destabilizing tear by the 48-month visit. We used two logistic regression models to assess whether: (1) presence of medial meniscal degeneration was associated with an incident medial destabilizing meniscal tear, and (2) presence of meniscal degeneration in either meniscus was associated with incident AKOA over the next 4 years. People with the presence of a medial meniscal degeneration had three times the odds of developing an incident destabilizing medial meniscal tear within 4 years compared with a person without medial meniscus degeneration (odds ratio [OR]: 3.03; 95% confidence interval [CI]: 1.40-6.59). People with meniscal degeneration had five times the odds of developing incident AKOA within 4 years compared with a person without meniscal degeneration in either meniscus (OR: 5.04; 95% CI: 2.57-9.89). Meniscal degeneration on MR is clinically meaningful as it relates to future poor outcomes.

Quantitative bone marrow lesion, meniscus, and synovitis measurement: current status

Imaging plays a pivotal role in osteoarthritis research, particularly in epidemiological and clinical trials of knee osteoarthritis (KOA), with the ultimate goal being the development of an effective drug treatment for future prevention or cessation of disease. Imaging assessment methods can be semi-quantitative, quantitative, or a combination, with quantitative methods usually relying on software to assist. The software generally attempts image segmentation (outlining of relevant structures). New techniques using artificial intelligence (AI) or deep learning (DL) are currently a frequent topic of research. This review article provides an overview of the literature to date, focusing primarily on the current status of quantitative software-based assessment techniques of KOA using magnetic resonance (MR) imaging. We will concentrate on the imaging evaluation of three specific structural imaging biomarkers: bone marrow lesions (BMLs), meniscus, and synovitis consisting of effusion synovitis (ES) and Hoffa's synovitis (HS). A brief clinical and imaging background review of osteoarthritis evaluation, particularly relating to these three structural markers, is provided as well as a general summary of the software methods. A summary of the literature with respect to each KOA assessment method will be presented overall as well as with respect to each specific biomarker individually. Novel techniques, as well as future goals and directions using quantitative imaging assessment, will be discussed.

High-resolution CINE imaging of active guided knee motion using continuously acquired golden-angle radial MRI and rotary sensor information

To explore and extend on dynamic imaging of joint motion, an MRI-safe device guiding knee motion with an attached rotary encoder was used in MRI measurements of multiple knee flexion-extension cycles using radial gradient echo imaging with the golden-angle as azimuthal angle increment. Reproducibility of knee motion was investigated. Real-time and CINE mode anatomical images were reconstructed for different knee flexion angles by synchronizing the encoder information with the MRI data, and performing flexion angle selective gating across multiple motion cycles. When investigating the influence of the rotation angle window width on reconstructed CINE images, it was found that angle windows between 0.5° and 3° exhibited acceptable image sharpness without suffering from significant motion-induced blurring. Furthermore, due to flexible retrospective image reconstruction afforded by the radial golden-angle imaging, the number of motion cycles included in the reconstruction could be retrospectively reduced to investigate the corresponding influence of acquisition time on image quality. Finally, motion reproducibility between motion cycles and accuracy of the flexion angle selective gating were sufficient to acquire whole-knee 3D dynamic imaging with a retrospectively gated 3D cone UTE sequence.

Gender-related differences in concomitant articular injuries after acute lateral patellar dislocation

OBJECTIVES

To explore the gender differences in the concomitant articular injuries after acute lateral patellar dislocation (LPD).

METHODS

Magnetic resonance images were prospectively analyzed in 166 patients after an acute LPD. Concomitant articular injuries included bone contusion, medial patellofemoral ligament (MPFL) injury, articular cartilage lesion, and vastus medialis obliquus (VMO) lesion. Statistical analyses were performed between the patient's gender and the incidence of concomitant articular injuries in adolescent and adult subgroups.

RESULTS

The incidence of partial and complete MPFL tear in adolescent males and females were (45%, 50%) and (63.2%, 29.8%), respectively. Compared with adolescent females, adolescent males showed higher incidence of complete MPFL tear (P = 0.049). The incidence of articular cartilage lesion of patella in adolescent males and females were 40% and 21.1%, respectively. Compared with adolescent females, adolescent males showed higher incidence of articular cartilage lesion of the patella (P = 0.043). No correlations were identified in other injuries in the adolescent group. The incidence of partial and complete MPFL tear in adult males and females were (34.4%, 65.6%) and (56.8%, 37.8%), respectively. Compared with adult females, adult males showed higher incidence of complete MPFL tear (P = 0.036). The incidence of articular cartilage lesion of patella in adult males and females were 56.3% and 32.4%, respectively. Compared with adult females, adult males showed higher incidence of articular cartilage lesion of patella (P = 0.047). The incidence of VMO injury in adult males and females were 59.4% and 35.1%, respectively. Compared with adult females, adult males showed higher incidence of VMO injury (P = 0.044). No correlations were identified in other injuries in the adult group.

CONCLUSIONS

Compared with females, males predispose to complete MPFL tear and articular cartilage lesion of patella after acute LPD. Compared with female adults, male adults predispose to VMO injury.

Multiple Subchondral Bone Cysts Cause Deterioration of Articular Cartilage in Medial OA of Knee: A 3D Simulation Study

Aims

To investigate the impact of subchondral bone cysts (SBCs) in stress-induced osseous and articular variations in cystic and non-cystic knee models using finite element analysis.

Materials and Methods

3D knee joint models were reconstructed from computed tomography (CT) and magnetic resonance imaging (MRI). Duplicate 3D models were also created with a 3D sphere mimicking SBCs in medial tibia. Models were divided into three groups. In group A, a non-cystic knee model was used, whereas in groups B and C, SBCs of 4 and 12 mm size were simulated, respectively. Cyst groups were further divided into three sub-groups. Each of sub-group 1 was composed of a solitary SBC in the anterior half of tibia adjacent to joint line. In sub-group 2, a solitary cyst was modeled at a lower-joint location, and in sub-group 3, two SBCs were used. All models were vertically loaded with weights representing double- and single-leg stances.

Results

During single-leg stance, increase in subchondral bone stress in sub-groups B-1 and B-3 were significant (p = 0.044, p = 0.026). However, in sub-group B-2, a slight increase was observed than non-cystic knee model (9.93 ± 1.94 vs. 9.35 ± 1.85; p = 0.254). All the sub-groups in group C showed significantly increased articular stress (p < 0.001). Conversely, a prominent increase in peri-cystic cancellous bone stress was produced by SBCs in groups B and C (p < 0.001). Mean cartilage shear stress in sub-groups B-1 and B-2 (0.66 ± 0.56, 0.58 ± 0.54) was non-significant (p = 0.374, p = 0.590) as compared to non-cystic model (0.47 ± 0.67). But paired cysts of the same size (B-3) produced a mean stress of 0.98 ± 0.49 in affected cartilage (p = 0.011). Models containing 12 mm SBCs experienced a significant increase in cartilage stress (p = 0.001, p = 0.006, p < 0.001) in sub-groups C-1, C-2, and C-3 (1.25 ± 0.69, 1.01 ± 0.54, and 1.26 ± 0.59), respectively.

Conclusion

The presence of large-sized SBCs produced an increased focal stress effect in articular cartilage. Multiple cysts further deteriorate the condition by increased osseous stress effect and high tendency of peripheral cyst expansion in simulated cystic knee models than non-cystic knee models.

Quantitative measurement of cartilage volume with automatic cartilage segmentation in knee osteoarthritis

PURPOSE

To determine the reproducibility of the automatic cartilage segmentation method using a prototype KneeCaP software (version 1.3; Siemens Healthcare, Erlangen, Germany) and to compare the difference in cartilage volume (CV) between the normal knee joint and knee osteoarthritis (KOA) of different degrees by using the above software.

MATERIALS AND METHODS

The study included 62 subjects with knee OA and 29 healthy control subjects. The cartilage lesion patients were divided into a mild-to-moderate OA group (n = 29) and severe OA group (n = 33). Automatic cartilage segmentation was performed on all the subjects, and among them, 19 knee cases were randomly selected to also do the manual cartilage segmentation. Statistical significance was determined with one-way analysis of variance (ANOVA), intraclass correlation coefficient (ICC), and Pearson correlation coefficient. Automatic segmentation was compared with the manual one. The relative cartilage volume percentages of the femur, tibia, and patella in the normal control/mild-to-moderate/severe OA groups were assessed.

RESULTS

Comparing the cartilage volumes derived by manual and automatic segmentation, the ICC value for the knee joint, patella, femur, or tibia was 0.784, 0.815, 0.740, and 0.797. The relative cartilage volume percentages of the femur, tibia, and patella in the normal control/mild-to-moderate/severe OA groups were 57.28%/59.30%/62.45% (femur), 25.35%/23.46%/21.84% (tibia), and 17.37%/17.24%/15.71% (patella), respectively. Compared with the normal control group, the relative tibia cartilage volume percentage was lower in the mild-to-moderate OA group and the severe OA group. Corresponding index showed a similar difference between the mild-to-moderate OA group and the severe OA group (p < 0.001).

CONCLUSION

This study demonstrated that the relative cartilage volume percentage is correlated with the semi-quantitative systems and may be a preferred outcome measure in clinical studies of OA. Automatic cartilage segmentation using KneeCaP delivered reliable results on high-spatial-resolution 3 T MR images for the healthy, mild-moderate OA patients. Key Points • The cartilage automatic segmentation has excellent reproducibility and was not affected by inter-observer variation. • The relative cartilage volume percentage is correlated with the semi-quantitative systems and may be a preferred outcome measure in clinical studies of OA.

Functionalization of Novel Theranostic Hydrogels with Kartogenin-Grafted USPIO Nanoparticles To Enhance Cartilage Regeneration

Here, kartogenin (KGN), an emerging stable nonprotein compound with the ability to promote differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) into chondrocytes, was grafted onto the surface of modified ultrasmall superparamagnetic iron-oxide (USPIO) and then integrated into cellulose nanocrystal/dextran hydrogels. The hydrogels served as a carrier for the USPIO-KGN and a matrix for cartilage repair. We carried out in vitro and in vivo studies, the results of which demonstrated that KGN undergoes long-term stable sustained release, recruits endogenous host cells, and induces BMSCs to differentiate into chondrocytes, thus enabling in situ cartilage regeneration. Meanwhile, the USPIO-incorporated theranostic hydrogels exhibited a distinct magnetic resonance contrast enhancement and maintained a stable relaxation rate, with almost no loss, both in vivo and in vitro. According to noninvasive in vivo observation results and immunohistochemistry analyses, the regenerated cartilage tissue was very similar to natural hyaline cartilage. This innovative diagnosis and treatment system increases the convenience and effectiveness of chondrogenesis.

Early pre-radiographic structural pathology precedes the onset of accelerated knee osteoarthritis

BACKGROUND

Accelerated knee osteoarthritis (AKOA) is characterized by more pain, impaired physical function, and greater likelihood to receive a joint replacement compared to individuals who develop the typical gradual onset of disease. Prognostic tools are needed to determine which structural pathologies precede the development of AKOA compared to individuals without AKOA. Therefore, the purpose of this manuscript was to determine which pre-radiographic structural features precede the development of AKOA.

METHODS

The sample comprised participants in the Osteoarthritis Initiative (OAI) who had at least one radiographically normal knee at baseline (Kellgren-Lawrence [KL] grade < 1). Participants were classified into 2 groups based on radiographic progression from baseline to 48 months: AKOA (KL grade change from < 1 to > 3) and No AKOA. The index visit was the study visit when participants met criteria for AKOA or a matched timepoint for those who did not develop AKOA. Magnetic resonance (MR) images were assessed for 12 structural features at the OAI baseline, and 1 and 2 years prior to the index visit. Separate logistic regression models (i.e. OAI baseline, 1 and 2 years prior) were used to determine which pre-radiographic structural features were more likely to antedate the development of AKOA compared to individuals not developing AKOA.

RESULTS

At the OAI baseline visit, degenerative cruciate ligaments (Odds Ratio [OR] = 2.2, 95% Confidence Interval [CI] = 1.3,3.5), infrapatellar fat pad signal intensity alteration (OR = 2.0, 95%CI = 1.2,3.2), medial/lateral meniscal pathology (OR = 2.1/2.4, 95%CI = 1.3,3.4/1.5,3.8), and greater quantitative knee effusion-synovitis (OR = 2.2, 95%CI = 1.4,3.4) were more likely to antedate the development of AKOA when compared to those that did not develop AKOA. These results were similar at one and two years prior to disease onset. Additionally, medial meniscus extrusion at one year prior to disease onset (OR = 3.5, 95%CI = 2.1,6.0) increased the likelihood of developing AKOA.

CONCLUSIONS

Early ligamentous degeneration, effusion/synovitis, and meniscal pathology precede the onset of AKOA and may be prognostic biomarkers.

Comparison of Near-Infrared Spectroscopy with Needle Indentation and Histology for the Determination of Cartilage Thickness in the Large Animal Model Sheep

The suitability of near-infrared spectroscopy (NIRS) for non-destructive measurement of cartilage thickness was compared with the gold standard needle indentation. A combination of NIRS and biomechanical indentation (NIRS-B) was used to address the influence of varying loads routinely applied for hand-guided NIRS during real-life surgery on the accuracy of NIRS-based thickness prediction. NIRS-B was performed under three different loading conditions in 40 osteochondral cylinders from the load-bearing area of the medial and lateral femur condyle of 20 cadaver joints (left stifle joints; female Merino sheep; 6.1 ± 0.6 years, mean ± standard error of the mean). The cartilage thickness measured by needle indentation within the region analyzed by NIRS-B was then compared with cartilage thickness prediction based on NIRS spectral data using partial least squares regression. NIRS-B repeat measurements yielded highly reproducible values concerning force and absorbance. Separate or combined models for the three loading conditions (the latter simulating load-independent measurements) resulted in models with optimized quality parameters (e.g., coefficients of determination R² between 92.3 and 94.7) and a prediction accuracy of < 0.1 mm. NIRS appears well suited to determine cartilage thickness (possibly in a hand-guided, load-independent fashion), as shown by high reproducibility in repeat measurements and excellent reliability compared with tissue-destructive needle indentation. This may provide the basis for non-destructive, intra-operative assessment of cartilage status quo and fine-tuning of repair procedures.

Knee osteoarthritis patients with more subchondral cysts have altered tibial subchondral bone mineral density

Background

Subchondral bone cysts are a widely observed, but poorly understood, feature in patients with knee osteoarthritis (OA). Clinical quantitative computed tomography (QCT) has the potential to characterize cysts in vivo but it is unclear which specific cyst parameters (e.g., number, size) are associated with clinical signs of OA, such as disease severity or pain. The objective of this study was to use QCT-based image-processing techniques to characterize subchondral tibial cysts in patients with knee OA and to explore relationships between proximal tibial subchondral cyst parameters and subchondral bone density as well as clinical characteristics of OA (alignment, joint space narrowing (JSN), OA severity, pain) in patients with knee OA.

Methods

The preoperative knee of 42 knee arthroplasty patients was scanned using QCT. Patient characteristics were obtained, including OA severity, knee pain, JSN, and alignment. We used 3D image processing techniques to obtain cyst parameters including: cyst number, cyst number per proximal tibial volume, cyst volume per proximal tibial volume, as well as maximum and average cyst volume across the proximal tibia, as well as regional bone mineral density (BMD) excluding cysts. We used Spearman’s correlation coefficients to explore associations between patient characteristics and cyst parameters.

Results

At both the medial and lateral compartments of the proximal tibia, greater cyst number and volume were associated with higher BMD. At the lateral region, cyst number and volume were also associated with lateral OA severity, lateral JSN, alignment and sex. Pain was not associated with any cyst parameters at any region.

Conclusion

Cyst number and volume were associated with BMD at both the medial and lateral compartments. Lateral cyst number and volume were also associated with joint alignment, OA severity, JSN and sex. This is the first study to use clinical QCT to explore subchondral tibial cysts in patients with knee OA and provides further evidence of the relationships between subchondral cysts and clinical OA characteristics.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2388-9) contains supplementary material, which is available to authorized users.

What is the role of imaging in the clinical diagnosis of osteoarthritis and disease management?

While OA is predominantly diagnosed on the basis of clinical criteria, imaging may aid with differential diagnosis in clinically suspected cases. While plain radiographs are traditionally the first choice of imaging modality, MRI and US also have a valuable role in assessing multiple pathologic features of OA, although each has particular advantages and disadvantages. Although modern imaging modalities provide the capability to detect a wide range of osseous and soft tissue (cartilage, menisci, ligaments, synovitis, effusion) OA-related structural damage, this extra information has not yet favourably influenced the clinical decision-making and management process. Imaging is recommended if there are unexpected rapid changes in clinical outcomes to determine whether it relates to disease severity or an additional diagnosis. On developing specific treatments, imaging serves as a sensitive tool to measure treatment response. This narrative review aims to describe the role of imaging modalities to aid in OA diagnosis, disease progression and management. It also provides insight into the use of these modalities in finding targeted treatment strategies in clinical research.

Non-invasive monitoring of in vivo hydrogel degradation and cartilage regeneration by multiparametric MR imaging

Numerous biodegradable hydrogels for cartilage regeneration have been widely used in the field of tissue engineering. However, to non-invasively monitor hydrogel degradation and efficiently evaluate cartilage restoration in situ is still challenging.

Methods: A ultrasmall superparamagnetic iron oxide (USPIO)-labeled cellulose nanocrystal (CNC)/silk fibroin (SF)-blended hydrogel system was developed to monitor hydrogel degradation during cartilage regeneration. The physicochemical characterization and biocompatibility of the hydrogel were evaluated in vitro. The in vivo hydrogel degradation and cartilage regeneration of different implants were assessed using multiparametric magnetic resonance imaging (MRI) and further confirmed by histological analysis in a rabbit cartilage defect model for 3 months.

Results: USPIO-labeled hydrogels showed sufficient MR contrast enhancement and retained stability without loss of the relaxation rate. Neither the mechanical properties of the hydrogels nor the proliferation of bone-marrow mesenchymal stem cells (BMSCs) were affected by USPIO labeling in vitro. CNC/SF hydrogels with BMSCs degraded more quickly than the acellular hydrogels as reflected by the MR relaxation rate trends in vivo. The morphology of neocartilage was noninvasively visualized by the three-dimensional water-selective cartilage MRI scan sequence, and the cartilage repair was further demonstrated by macroscopic and histological observations.

Conclusion: This USPIO-labeled CNC/SF hydrogel system provides a new perspective on image-guided tissue engineering for cartilage regeneration.

Mesenchymal Stem Cell Alterations in Bone Marrow Lesions in Patients With Hip Osteoarthritis

Objective

In patients with osteoarthritis (OA), bone marrow lesions (BMLs) are intimately linked to disease progression. We hypothesized that aberrant multipotential stromal cell (also known as mesenchymal stem cell [MSC]) responses within bone tissue contributes to BML pathophysiology. The aim of this study was to investigate BML and non‐BML native subchondral bone MSCs for numeric, topographic, in vitro functional, and gene expression differences.

Methods

Ex vivo 3T magnetic resonance imaging (MRI) of the femoral heads of 20 patients with hip OA was performed. MRI‐determined BML and non‐BML regions were excised and enzymatically treated to extract cells and quantify MSCs using flow cytometry and colony‐forming unit–fibroblast (CFU‐F) assay. Immunohistochemical analysis was performed to determine in vivo CD271+ MSC distribution. Culture‐expanded CD271+ cells were analyzed for tripotentiality and gene expression.

Results

BML regions were associated with greater trabecular bone area and cartilage damage compared with non‐BML regions. The proportion of CD45−CD271+ MSCs was higher in BML regions compared with non‐BML regions (median difference 5.6‐fold; P < 0.001); the CFU‐F assay showed a similar trend (median difference 4.3‐fold; P = 0.013). Immunohistochemistry revealed CD271+ cell accumulation in bone adjacent to cartilage defects and areas of osteochondral angiogenesis. BML MSCs had lower proliferation and mineralization capacities in vitro and altered expression of TNFSF11/RANKL and CXCR4/stromal cell–derived factor 1 receptor. OA MSCs showed up‐regulated transcripts for CXCR1 and CCR6 compared with MSCs derived from healthy or osteoporotic bone.

Conclusion

This study is the first to show numeric and topographic alterations in native MSCs in the diseased bone of patients with hip OA. Given the associated functional perturbation of MSCs, these data suggest that subchondral bone MSC manipulation may be an OA treatment target.

Imaging of Osteoarthritis in Geriatric Patients

Imaging of osteoarthritis (OA) in the elderly is gaining importance because of the aging population. It requires knowledge about findings relevant for patient management and others which are abnormal findings, but part of normal aging without relevance for patient management due to lack of clinical symptoms. This review will provide information on what imaging techniques are best used for knee OA and how to systematically assess knee joint structures in order to cover the most common asymptomatic and symptomatic MR findings in OA. We will discuss which findings are typically found in older patients and which are likely to progress to severe pain and disability, finally leading to total joint replacement. The review may aid radiologists and referring clinicians to better understand the evolution of symptomatic OA and the current or future clinical significance of the most common symptomatic and asymptomatic findings.

MR Imaging-based Semi-quantitative Methods for Knee Osteoarthritis

Magnetic resonance imaging (MRI)-based semi-quantitative (SQ) methods applied to knee osteoarthritis (OA) have been introduced during the last decade and have fundamentally changed our understanding of knee OA pathology since then. Several epidemiological studies and clinical trials have used MRI-based SQ methods to evaluate different outcome measures. Interest in MRI-based SQ scoring system has led to continuous update and refinement. This article reviews the different SQ approaches for MRI-based whole organ assessment of knee OA and also discuss practical aspects of whole joint assessment.

Injury patterns of medial patellofemoral ligament and correlation analysis with articular cartilage lesions of the lateral femoral condyle after acute lateral patellar dislocation in adults: An MRI evaluation

OBJECTIVES

The purpose of this study was to investigate the injury characteristics of medial patellofemoral ligament (MPFL), and to analyse the correlations between the injury patterns of MPFL and articular cartilage lesions of the lateral femoral condyle in adults with acute lateral patellar dislocation (LPD).

METHODS

Magnetic resonance (MR) images were prospectively obtained in 121 consecutive adults with acute LPD. Images were acquired using standardised protocols and these were independently evaluated by two radiologists.

RESULTS

Forty-eight cases of partial MPFL tear and 71 cases of complete MPFL tear were identified. Injuries occurred at an isolated femoral attachment (FEM) in 48 cases, an isolated patellar insertion (PAT) in 36 cases and an isolated mid-substance (MID) in five cases. More than one site of injury to the MPFL (COM) was identified in 30 cases. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 4.2% (2/48) and 6.3% (3/48) in the FEM subgroup, 19.4% (7/36) and 22.2% (8/36) in the PAT subgroup and 6.7% (2/30) and 13.3% (4/30) in the COM subgroup, respectively. The PAT subgroup showed significantly higher prevalence rate of chondral and osteochondral lesions in the lateral femoral condyle when compared with the FEM subgroup. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 8.5% (6/71) and 19.7% (14/71) in the complete MPFL tear subgroup and 10.4% (5/48) and 4.2% (2/58) in the partial MPFL tear subgroup, respectively. The subgroup of the complete MPFL tear showed significantly higher prevalence rate of osteochondral lesions in the lateral femoral condyle when compared with the subgroup of the partial MPFL tear.

CONCLUSIONS

Firstly, the MPFL is most easily injured at the FEM, and secondly at the PAT in adults after acute LPD. The complete MPFL tear is more often concomitant with osteochondral lesions of the lateral femoral condyle than the partial MPFL tear. The isolated patellar-sided MPFL tear is more easily concomitant with chondral lesions and osteochondral lesions of the lateral femoral condyle than the isolated femoral-sided MPFL tear.

Injury patterns of medial patellofemoral ligament and correlation analysis with articular cartilage lesions of the lateral femoral condyle after acute lateral patellar dislocation in children and adolescents: An MRI evaluation

OBJECTIVES

The purpose of this study was to investigate the injury characteristics of medial patellofemoral ligament (MPFL), and to analyse the correlations between the injury patterns of MPFL and articular cartilage lesions of the lateral femoral condyle in children and adolescents with acute lateral patellar dislocation (LPD).

METHODS

Magnetic resonance (MR) images were prospectively obtained in 127 consecutive children and adolescents with acute LPD. Images were acquired using standardised protocols and these were independently evaluated by two radiologists.

RESULTS

Fifty-four cases of partial MPFL tear and 69 cases of complete MPFL tear were identified. Injuries occurred at an isolated patellar insertion (PAT) in 47 cases, an isolated femoral attachment (FEM) in 41 cases and an isolated mid-substance (MID) in four cases. More than one site of injury to the MPFL (COM) was identified in 31 cases. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 23.4% (11/47) and 29.8% (14/47) in the PAT subgroup, 7.3% (3/41) and 9.8% (4/41) in the FEM subgroup and 25.8% (8/31) and 32.3% (10/31) in the COM subgroup, respectively. The PAT and COM subgroups showed significantly higher prevalence rate of chondral and osteochondral lesions in the lateral femoral condyle when compared with the FEM subgroup. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 17.4% (12/69) and 30.4% (21/69) in the complete MPFL tear subgroup and 20.4% (11/54) and 13% (7/54) in the partial MPFL tear subgroup, respectively. The subgroup of the complete MPFL tear showed significantly higher prevalence rate of osteochondral lesions in the lateral femoral condyle when compared with the subgroup of the partial MPFL tear.

CONCLUSIONS

Firstly, the MPFL is most easily injured at the PAT, and secondly at the FEM in children and adolescents after acute LPD. The complete MPFL tear is more often concomitant with osteochondral lesions of the lateral femoral condyle than the partial MPFL tear. The isolated patellar-sided MPFL tear and the combined MPFL tear are more easily concomitant with chondral lesions and osteochondral lesions of the lateral femoral condyle than the isolated femoral-sided MPFL tear.

2D and 3D MOCART scoring systems assessed by 9.4 T high-field MRI correlate with elementary and complex histological scoring systems in a translational model of osteochondral repair

OBJECTIVE

To compare the 2D and 3D MOCART system obtained with 9.4 T high-field magnetic resonance imaging (MRI) for the ex vivo analysis of osteochondral repair in a translational model and to correlate the data with semiquantitative histological analysis.

METHODS

Osteochondral samples representing all levels of repair (sheep medial femoral condyles; n = 38) were scanned in a 9.4 T high-field MRI. The 2D and adapted 3D MOCART systems were used for grading after point allocation to each category. Each score was correlated with corresponding reconstructions between both MOCART systems. Data were next correlated with corresponding categories of an elementary (Wakitani) and a complex (Sellers) histological scoring system as gold standards.

RESULTS

Correlations between most 2D and 3D MOCART score categories were high, while mean total point values of 3D MOCART scores tended to be 15.8-16.1 points higher compared to the 2D MOCART scores based on a Bland-Altman analysis. "Defect fill" and "total points" of both MOCART scores correlated with corresponding categories of Wakitani and Sellers scores (all P ≤ 0.05). "Subchondral bone plate" also correlated between 3D MOCART and Sellers scores (P < 0.001).

CONCLUSIONS

Most categories of the 2D and 3D MOCART systems correlate, while total scores were generally higher using the 3D MOCART system. Structural categories "total points" and "defect fill" can reliably be assessed by 9.4 T MRI evaluation using either system, "subchondral bone plate" using the 3D MOCART score. High-field MRI is valuable to objectively evaluate osteochondral repair in translational settings.

Assessment of hyaline cartilage matrix composition using near infrared spectroscopy

Changes in the composition of the extracellular matrix (ECM) are characteristic of injury or disease in cartilage tissue. Various imaging modalities and biochemical techniques have been used to assess the changes in cartilage tissue but lack adequate sensitivity, or in the case of biochemical techniques, result in destruction of the sample. Fourier transform near infrared (FT-NIR) spectroscopy has shown promise for the study of cartilage composition. In the current study NIR spectroscopy was used to identify the contributions of individual components of cartilage in the NIR spectra by assessment of the major cartilage components, collagen and chondroitin sulfate, in pure component mixtures. The NIR spectra were obtained using homogenous pellets made by dilution with potassium bromide. A partial least squares (PLS) model was calculated to predict composition in bovine cartilage samples. Characteristic absorbance peaks between 4000 and 5000 cm(-1) could be attributed to components of cartilage, i.e. collagen and chondroitin sulfate. Prediction of the amount of collagen and chondroitin sulfate in tissues was possible within 8% (w/dw) of values obtained by gold standard biochemical assessment. These results support the use of NIR spectroscopy for in vitro and in vivo applications to assess matrix composition of cartilage tissues, especially when tissue destruction should be avoided.

Quantitative versus semiquantitative MR imaging of cartilage in blood-induced arthritic ankles: preliminary findings

BACKGROUND

Recent advances in hemophilia prophylaxis have raised the need for accurate noninvasive methods for assessment of early cartilage damage in maturing joints to guide initiation of prophylaxis. Such methods can either be semiquantitative or quantitative. Whereas semiquantitative scores are less time-consuming to be performed than quantitative methods, they are prone to subjective interpretation.

OBJECTIVE

To test the feasibility of a manual segmentation and a quantitative methodology for cross-sectional evaluation of articular cartilage status in growing ankles of children with blood-induced arthritis, as compared with a semiquantitative scoring system and clinical-radiographic constructs.

MATERIALS AND METHODS

Twelve boys, 11 with hemophilia (A, n = 9; B, n = 2) and 1 with von Willebrand disease (median age: 13; range: 6-17), underwent physical examination and MRI at 1.5 T. Two radiologists semiquantitatively scored the MRIs for cartilage pathology (surface erosions, cartilage loss) with blinding to clinical information. An experienced operator applied a validated quantitative 3-D MRI method to determine the percentage area of denuded bone (dAB) and the cartilage thickness (ThCtAB) in the joints' MRIs. Quantitative and semiquantitative MRI methods and clinical-radiographic constructs (Hemophilia Joint Health Score [HJHS], Pettersson radiograph scores) were compared.

RESULTS

Moderate correlations were noted between erosions and dAB (r = 0.62, P = 0.03) in the talus but not in the distal tibia (P > 0.05). Whereas substantial to high correlations (r range: 0.70-0.94, P < 0.05) were observed between erosions, cartilage loss, HJHS and Pettersson scores both at the distal tibia and talus levels, moderate/borderline substantial (r range: 0.55-0.61, P < 0.05) correlations were noted between dAB/ThCtAB and clinical-radiographic constructs.

CONCLUSION

Whereas the semiquantitative method of assessing cartilage status is closely associated with clinical-radiographic scores in cross-sectional studies of blood-induced arthropathy, quantitative measures provide independent information and are therefore less applicable for that research design.

Increased cartilage volume after injection of hyaluronic acid in osteoarthritis knee patients who underwent high tibial osteotomy

PURPOSE

High tibial osteotomy (HTO) is a surgical procedure used to correct abnormal mechanical loading of the knee joint; additionally, intra-articular hyaluronic acid injections have been shown to restore the viscoelastic properties of synovial fluid and balance abnormal biochemical processes. It was hypothesized that combining HTO with intra-articular hyaluronic acid injections would have benefit to improve the cartilage volume of knee joints.

METHODS

Forty patients with medial compartment knee osteoarthritis (OA) were randomly placed into 1 of 2 groups. The study group (n = 20) received 2 cycles (at 6-month intervals) of 5 weekly intra-articular hyaluronic acid injections after HTO operation. The control group (n = 20) did not receive any intra-articular injections after HTO surgery. Cartilage volume (primary outcome) was assessed by magnetic resonance imaging (MRI) pre-operatively and 1 year post-operatively. Treatment efficacy (secondary outcomes) was evaluated with the Western Ontario and McMaster Universities OA Index (WOMAC) and by the comparison of the total rescue medication (paracetamol/diclofenac) used (weeks 6, 12, 24, 48).

RESULTS

MRI studies showed a significant increase in total cartilage volume (p = 0.033), lateral femoral cartilage volume (p = 0.044) and lateral tibial cartilage volume (p = 0.027) in the study group. Cartilage volume loss was detected at the lateral tibial plateau in the control group. There were significant improvements after surgery in both groups for all subscales of WOMAC scores (p < 0.001) compared to the baseline. However, no difference was found between the two groups. The study group had significantly lower amounts of diclofenac consumption (p = 0.017).

CONCLUSION

Based on the findings of the present study, intra-articular hyaluronic acid injections may be beneficial for increasing total cartilage volume and preventing the loss of lateral tibiofemoral joint cartilage after HTO.

LEVEL OF EVIDENCE

Therapeutic study, Level I.

Quantitative magnetic resonance imaging assessment of cartilage status: a comparison between young men with and without anterior cruciate ligament reconstruction

PURPOSE

To assess the cartilage status of the knee joints using magnetic resonance imaging at least 2 years after anterior cruciate ligament reconstruction (ACLR) in young adult men.

METHODS

Thirty young male patients with unilateral ACLR and 15 age-matched and body mass index--matched healthy men (controls) participated in this study. All participants underwent quantitative magnetic resonance imaging scans. Three-dimensional dual-echo steady-state sagittal images were segmented using solid model software to calculate the mean cartilage thickness, and multi-echo sagittal images were segmented with Siemens software (Siemens, Erlangen, Germany) to determine the T2 relaxation time of each cartilage plate.

RESULTS

There was no statistically significant difference in the mean thickness of each cartilage plate between the ACLR and control groups (P = .9616 for lateral femoral cartilage, P = .5962 for lateral tibial cartilage, P = .9328 for patellar cartilage, P = .9712 for trochlear cartilage, P = .4408 for medial femoral cartilage, and P = .1933 for medial tibial cartilage). The ACLR group had significantly higher T2 values than the control group in the lateral femoral cartilage (P < .001), lateral tibia (P = .0011), trochlea (P = .0028), medial femur (P < .001), and medial tibia (P < .001). In addition, the patella showed no difference in T2 values between the 2 groups (P = .2152). The medial compartment cartilage showed a much higher percentage change in cartilage T2 values in the ACLR group.

CONCLUSIONS

Although no difference in cartilage thickness was detected between the ACLR group and the control group, the mean T2 relaxation time in the ACLR patients was significantly longer than that in control subjects.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Low accuracy of interpretation of rotator cuff MRI in patients with osteoarthritis

BACKGROUND

Magnetic resonance imaging (MRI) is considered to be a valuable tool for the diagnosis of rotator cuff tears in patients with severe glenohumeral osteoarthritis who are indicated for total shoulder arthroplasty (TSA). We determined the sensitivity, specificity, and positive predictive value of MRI in diagnosing rotator cuff tears in such patients.

METHODS

MRI reports of 100 patients who had completed a shoulder MRI prior to TSA were reviewed to determine the radiologists' interpretation of the MRI including the diagnosis, presence of a full-thickness cuff tear, and the presence of atrophy and/or fatty infiltration within the rotator cuff muscle bellies. Operative reports were used as a gold standard to determine whether a full-thickness rotator cuff tear was present.

RESULTS

Preoperative MRI reports noted 33 of the 100 patients as having a full-thickness rotator cuff tear, 17 of which had multiple tendon tears. 2 of the 33 patients with full tears on MRI were found to have full-thickness tears at surgery. The sensitivity, specificity, and positive predictive value for MRI detection of full-thickness tears were 100%, 68%, and 6% respectively, with a false-positive rate of 32% and an accuracy of 69%.

INTERPRETATION

The study suggests that although MRI is highly sensitive, it has a low positive predictive value and moderately low specificity and accuracy in detecting full-thickness rotator cuff tears in patients with severe glenohumeral osteoarthritis.

A rapid, novel method of volumetric assessment of MRI-detected subchondral bone marrow lesions in knee osteoarthritis

PURPOSE

To assess reliability and validity of a semi-automated quantitative method for osteoarthritis (OA)-related bone marrow lesion (BML) assessment in the femur and tibia.

METHODS

In a cross-sectional study of subjects with knee OA, we examined concurrent criterion and clinical validation of a novel method of semi-automated quantitative BML measurement. The primary outcome was total segmented BML volume in femoral and tibial medial and lateral knee compartments. Criterion validation was examined through comparison of BML volumes with Whole-Organ Magnetic Resonance Imaging Score (WORMS) scoring. Clinical validation was examined via associations of tibial and femoral BML volume with the Western Ontario and McMaster University OA Index weight-bearing pain questions.

RESULTS

Among the 115 subjects, mean age was 62 years, mean BMI 30.4 (kg/m(2)), 84% were white and 52% male. The intra-class correlation coefficients (ICC) for intra-reader reliability was 0.96 and 0.97 for inter-reader reliability. Significant Spearman's correlations were found between segmented BML volume and WORMS BML scoring for tibial medial (0.75) and lateral (0.73) compartments, and for femoral medial (0.72) and lateral (0.88) compartments. Significant positive associations were found between weight-bearing pain and total femoral BML volume (P < 0.003), but not total tibial BML (P < 0.101).

CONCLUSION

We have documented a moderately strong correlation between a novel measurement method of femoral and tibial BML volume and semi-quantitative WORMS scores, providing evidence of criterion validity. The hypothesis that weight-bearing pain was associated with BML volume was confirmed for total femoral BML volume but not total tibial BML volume. The lack of association between tibial BML volume and pain requires further investigation.

Radiographic osteoarthritis and pain are independent predictors of knee cartilage loss: a prospective study

BACKGROUND

There is controversy about whether pain and radiographic osteoarthritis (ROA) predict subsequent cartilage loss. The aim of this study was to describe the relationship between ROA, pain and cartilage loss in the knee.

METHODS

We studied randomly selected subjects at baseline and approximately 2.9 years later (n= 399). The presence of ROA was assessed at baseline with a standing anteroposterior semiflexed radiograph scored using the Osteoarthritis Research Society International atlas for osteophytes (OP) and joint space narrowing (JSN). Pain was assessed by the Western Ontario McMaster Osteoarthritis Index. Subjects' medial and lateral tibial cartilage volumes were determined by magnetic resonance imaging at both time points.

RESULTS

In cross-sectional analysis, both medial and lateral tibial cartilage volumes were lower in those with ROA. Any medial ROA predicted medial tibial cartilage loss (3.2% (standard deviation (SD) 5.6) vs 1.9% (SD 5.3) per annum) while any lateral ROA predicted both medial (4.0% (SD 6.0) vs 2.2% (SD 5.3) per annum) and lateral (3.5% (SD 5.8) vs 1.6% (SD 4.2) per annum) tibial cartilage loss (all P < 0.05). In multivariate analysis, JSN and OP at both medial and lateral sites had independent dose-response associations with tibial cartilage loss at both sites. Pain was an independent predictor of lateral, but not medial, tibial cartilage loss after taking ROA into account.

CONCLUSIONS

Subjects with ROA (either JSN or OP) and, to a lesser extent, pain lose cartilage faster than subjects without ROA and the more severe the ROA the greater the rate of loss. These findings have implications for the design of clinical trials.

Magnetic resonance imaging of subchondral bone marrow lesions in association with osteoarthritis

OBJECTIVES

This nonsystematic literature review provides an overview of magnetic resonance imaging (MRI) of subchondral bone marrow lesions (BMLs) in association with osteoarthritis (OA), with particular attention to the selection of MRI sequences and semiquantitative scoring systems, characteristic morphology, and differential diagnosis. Histologic basis, natural history, and clinical significance are also briefly discussed.

METHODS

PubMed was searched for articles published up to 2011, using the keywords bone marrow lesion, osteoarthritis, magnetic resonance imaging, bone marrow edema, histology, pain, and subchondral.

RESULTS

BMLs in association with OA correspond to fibrosis, necrosis, edema, and bleeding of fatty marrow as well as abnormal trabeculae on histopathology. Lesions may fluctuate in size within a short time and are associated with the progression of articular cartilage loss and fluctuation of pain in knee OA. The characteristic subchondral edema-like signal intensity of BMLs should be assessed using T2-weighted, proton density-weighted, intermediate-weighted fat-suppressed fast spin echo or short tau inversion recovery. Several semiquantitative scoring systems are available to characterize and grade the severity of BMLs. Quantitative approaches have also been introduced. Differential diagnoses of degenerative BMLs include a variety of traumatic or nontraumatic pathologies that may appear similar to OA-related BMLs on MRI.

CONCLUSIONS

Subchondral BMLs are a common imaging feature of OA with clinical significance and typical signal alteration patterns, which can be assessed and graded by semiquantitative scoring systems using sensitive MRI sequences.

Use magnetic resonance imaging to assess articular cartilage

Magnetic resonance imaging (MRI) enables a noninvasive, three-dimensional assessment of the entire joint, simultaneously allowing the direct visualization of articular cartilage. Thus, MRI has become the imaging modality of choice in both clinical and research settings of musculoskeletal diseases, particular for osteoarthritis (OA). Although radiography, the current gold standard for the assessment of OA, has had recent significant technical advances, radiographic methods have significant limitations when used to measure disease progression. MRI allows accurate and reliable assessment of articular cartilage which is sensitive to change, providing the opportunity to better examine and understand preclinical and very subtle early abnormalities in articular cartilage, prior to the onset of radiographic disease. MRI enables quantitative (cartilage volume and thickness) and semiquantitative assessment of articular cartilage morphology, and quantitative assessment of cartilage matrix composition. Cartilage volume and defects have demonstrated adequate validity, accuracy, reliability and sensitivity to change. They are correlated to radiographic changes and clinical outcomes such as pain and joint replacement. Measures of cartilage matrix composition show promise as they seem to relate to cartilage morphology and symptoms. MRI-derived cartilage measurements provide a useful tool for exploring the effect of modifiable factors on articular cartilage prior to clinical disease and identifying the potential preventive strategies. MRI represents a useful approach to monitoring the natural history of OA and evaluating the effect of therapeutic agents. MRI assessment of articular cartilage has tremendous potential for large-scale epidemiological studies of OA progression, and for clinical trials of treatment response to disease-modifying OA drugs.

Association of magnetic resonance imaging-based knee cartilage T2 measurements and focal knee lesions with knee pain: data from the Osteoarthritis Initiative

OBJECTIVE

To evaluate the association of magnetic resonance imaging (MRI)-based knee cartilage T2 measurements and focal knee lesions with knee pain in knees without radiographic osteoarthritis (OA) among subjects with OA risk factors.

METHODS

We studied the right knees of 126 subjects from the Osteoarthritis Initiative database. We randomly selected 42 subjects ages 45-55 years with OA risk factors, right knee pain (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] pain score ≥5), no left knee pain (WOMAC pain score 0), and no radiographic OA (Kellgren/Lawrence [K/L] score ≤1) in the right knee. We also selected 2 comparison groups: 42 subjects without knee pain in either knee and 42 with bilateral knee pain. Both groups were frequency matched to subjects with right knee pain only by sex, age, body mass index, and K/L score. All of the subjects underwent 3T MRI of the right knee. Focal knee lesions were assessed and cartilage T2 measurements were performed.

RESULTS

Prevalences of meniscal, bone marrow, and ligamentous lesions and joint effusion were not significantly different between the groups (P > 0.05), while cartilage lesions were more frequent in subjects with right knee pain only compared to subjects without knee pain (P < 0.05). T2 values averaged over all of the compartments were similar in subjects with right knee pain only (mean ± SD 34.4 ± 1.8 msec) and in subjects with bilateral knee pain (mean ± SD 34.7 ± 4.7 msec), but were significantly higher compared to subjects without knee pain (mean ± SD 32.4 ± 1.8 msec; P < 0.05).

CONCLUSION

These results suggest that elevated cartilage T2 values are associated with findings of pain in the early phase of OA, whereas among morphologic knee abnormalities only knee cartilage lesions are significantly associated with knee pain status.

From joint anatomy to clinical outcomes in osteoarthritis and cartilage repair: summary of the fifth annual osteoarthritis imaging workshop

OBJECTIVE

This white paper constitutes an overview of presentations and discussions from the fifth Annual Workshop on Imaging in Osteoarthritis (OA) held in Salzburg June eighth to eleventh 2011.

DESIGN

This workshop brought together the communities of basic OA researchers, orthopedists and rheumatologists, imaging scientists, instrument manufacturers, and pharmaceutical representatives to focus on three overlapping themes of joint anatomy, cartilage repair and clinical validation of imaging biomarkers.

RESULTS

The workshop was held on the campus of the Paracelsus Medical University in Salzburg, Austria from June 8-11, 2011; 133 attendees participated, representing 17 countries. The meeting was successful in facilitating discussion, raising awareness and consolidating knowledge about application of imaging in OA research studies and cartilage repair.

CONCLUSIONS

The OA research communities need to work alongside the regulatory, pharmaceutical, and MRI industries to support the new ideas and engage in the positive reinforcement of resources to further the new studies. A number of new initiatives were discussed to further break down obstacles to clinical trial utility of imaging biomarkers.

Knee cartilage T2 characteristics and evolution in relation to morphologic abnormalities detected at 3-T MR imaging: a longitudinal study of the normal control cohort from the Osteoarthritis Initiative

PURPOSE

To determine the frequency of degenerative knee morphologic abnormalities in asymptomatic individuals by using 3-T magnetic resonance (MR) imaging and to investigate the characteristics and evolution of cartilage T2 values in relation to morphologic abnormalities with a longitudinal study.

MATERIALS AND METHODS

The study was approved by the institutional review board and was compliant with HIPAA. Ninety-five asymptomatic subjects aged 45-78 years who were free of risk factors for osteoarthritis (OA) were selected from the Osteoarthritis Initiative normal control cohort and examined with radiography and 3-T MR imaging. Data obtained at both baseline and 2-year follow-up were analyzed. OA-related knee abnormalities were analyzed by using the whole-organ MR imaging score (WORMS). Cartilage T2 maps were generated by using sagittal two-dimensional multiecho spin-echo images of the right knee. Statistical significance was determined with the Student t test, the paired t test, a mixed random effects model, one-way analysis of variance, and a multiple linear regression model.

RESULTS

Knee abnormalities were identified with a high frequency (90% at baseline and 92% at 2-year follow-up). The prevalence of hyaline cartilage lesions was particularly high (86% at baseline and 84% at follow-up). A significant longitudinal increase in T2 was detected in the tibiofemoral cartilage but not the patellofemoral cartilage (P = .0072). The longitudinal change in T2 was significantly associated with worsening of the cartilage WORMS (P = .038).

CONCLUSION

Asymptomatic subjects have a high frequency of OA-related morphologic abnormalities. A significant increase in tibiofemoral cartilage T2 was detected over the 2-year period. A greater increase in T2 was associated with increased progression of cartilage morphologic abnormalities.

The impact of MRI on the clinical management of inflammatory arthritides

In the past two decades, MRI has gained a major role in research and clinical management of patients with inflammatory arthritides, particularly in spondyloarthritis (SpA), rheumatoid arthritis (RA), and osteoarthritis (OA). MRI is regarded as the most sensitive imaging modality for detecting early SpA in young patients with inflammatory back pain and normal radiographs of the sacroiliac joints. The recently published Assessment of SpondyloArthritis International Society classification criteria for axial SpA include for the first time a positive MRI demonstrating sacroiliitis as an imaging criterion indicative of SpA together with at least one clinical feature of SpA. Recent data show that systematic assessment of sacroiliitis displayed on MRI has much greater diagnostic utility than previously reported and highlight the diagnostic relevance of structural lesions. In RA, MRI has predictive value for the development of disease in new onset undifferentiated arthritis, and MR pathology at disease onset is a highly significant predictor of radiographic erosions. Consequently MRI has been credited with an important role in the new ACR/EULAR 2010 classification criteria for RA. In OA, bone marrow edema (BME) and synovitis may serve as biomarkers in interventional trials. Treatment interventions targeting BME and synovitis observed on MRI in inflammatory arthritides may have a disease-modifying effect as these lesions are potentially reversible and have been shown to be associated with structural progression. Research should focus on the prognostic significance of MRI lesions in larger cohorts and whether adding MRI to routine care improves clinical and radiographic outcome in patients with inflammatory arthritides.

Hip Osteoarthritis MRI Scoring System (HOAMS): reliability and associations with radiographic and clinical findings

OBJECTIVE

To develop a semiquantitative MRI-based scoring system (HOAMS) of hip osteoarthritis (OA) and test its reliability and validity.

DESIGN

Fifty-two patients with chronic hip pain were included. 1.5T magnetic resonance imaging (MRI) was performed on all patients. Pelvic radiographs were scored according to the Kellgren-Lawrence (KL) system. Clinical outcomes were assessed by the hip osteoarthritis outcome score (HOOS). MRIs were analyzed using a novel whole-joint MRI score that incorporated 13 articular features. Reliability was determined on a random subset of 15 cases. Weighted-kappa statistics and overall agreement were used as a measure of intra- and inter-observer reliability. Associations between MRI features and radiographic OA severity were calculated using Cochran-Armitage test for trend. Ordinal logistic regression was used to assess associations between MRI features and severity of pain and functional limitation.

RESULTS

Distribution of radiographic grading was: KL 0=12 (27%), KL 1=11 (25%), KL 2=14 (32%), KL 3=5 (11%) and KL 4=2 (5%). Intra-reader reliability for the different features ranged from 0.18 (cysts) to 0.85 (cartilage). Inter-reader reliability ranged between 0.15 (cysts) and 0.85 (BMLs). Low kappas were due to low frequencies of some features as overall percent agreement was good to excellent (83.8% and 83.1%). There was a strong association between MRI-detected lesions and radiographic severity (P=0.002). Non-significant trends were observed between MRI features and clinical outcomes.

CONCLUSION

MRI-based semiquantitative assessment of the hip shows adequate reliability. Presence of more severe MRI-detected intraarticular pathology shows a strong association with radiographic OA. The results suggest possible associations between MRI-detected pathology and clinical symptoms.

Initial results on development and application of statistical atlas of femoral cartilage in osteoarthritis to determine sex differences in structure: data from the Osteoarthritis Initiative

PURPOSE

To create an average atlas of knee femoral cartilage morphology, to apply the atlas for quantitative assessment of osteoarthritis (OA), and to study localized sex differences.

MATERIALS AND METHODS

High-resolution 3D magnetic resonance imaging (MRI) data of the knee cartilage collected at 3 T as part of the Osteoarthritis Initiative (OAI) were used. An atlas was created based on images from 30 male Caucasian high-risk subjects with no symptomatic OA at baseline. A female cohort of age- and disease-matched Caucasian subjects was also selected from the OAI database. The Jacobian determinant was calculated from the deformation vector fields that nonlinearly registered each subject to the atlas. Statistical analysis based on the general linear model was used to test for regions of significant differences in the Jacobian values between the two cohorts.

RESULTS

The average Jacobian was larger in women (1.2 ± 0.078) than in men (1.08 ± 0.097), showing that after global scaling to the male template, the female cartilage was thicker in most regions. Regions showing significant structural differences include the medial weight bearing region, the trochlear (femoral) side of the patellofemoral compartment, and the lateral posterior condyle.

CONCLUSION

Sex-based differences in cartilage structure were localized using tensor based morphometry in a cohort of high-risk subjects.

Chondroitin sulphate reduces both cartilage volume loss and bone marrow lesions in knee osteoarthritis patients starting as early as 6 months after initiation of therapy: a randomised, double-blind, placebo-controlled pilot study using MRI

Objective

To determine the effect of chondroitin sulphate (CS) treatment on cartilage volume loss, subchondral bone marrow lesions (BML), synovitis and disease symptoms in patients with knee osteoarthritis (OA).

Methods

In this pilot multicentre, randomised, double-blind, controlled trial in primary knee OA, 69 patients with clinical signs of synovitis were randomised to receive CS 800 mg or placebo once daily for 6 months followed by an open-label phase of 6 months in which patients in both groups received CS 800 mg once daily. Cartilage volume and BML were assessed by MRI at baseline and at 6 and 12 months; synovial membrane thickness was assessed at baseline and at 6 months.

Results

The CS group showed significantly less cartilage volume loss than the placebo group as early as 6 months for the global knee (p=0.030), lateral compartment (p=0.015) and tibial plateaus (p=0.002), with significance persisting at 12 months. Significantly lower BML scores were found for the CS group at 12 months in the lateral compartment (p=0.035) and the lateral femoral condyle (p=0.044). Disease symptoms were similar between the two groups.

Conclusion

CS treatment significantly reduced the cartilage volume loss in knee OA starting at 6 months of treatment, and BML at 12 months. These findings suggest a joint structure protective effect of CS and provide new in vivo information on its mode of action in knee OA.

Subchondral cysts create increased intra-osseous stress in early knee OA: A finite element analysis using simulated lesions

AIM OF STUDY

To investigate the role of intra-osseous lesions in advancing the pathogenesis of Osteoarthritis (OA) of the knee, using Finite Element Modeling (FEM) in conjunction with high-resolution imaging techniques.

METHODS

Twenty early stage OA patients (≤ Grade 2 radiographic score) were scanned with a prototype, cone-beam CT system. Scans encompassed the mid-shaft of the femur to the diaphysis of the proximal tibia. Individual bones were segmented to create 3D geometric models that were transferred to FE software for loading experiments. Patient-specific, inhomogeneous material properties were derived from the CT images and mapped directly to the FE models. Duplicate models were also created, with a 3D sphere (range 3-12 mm) introduced into a weight-bearing region of the joint, mimicking the size, location, and composition of a subchondral bone cyst (SBC). A spherical shell extending 1mm radially around the SBC served as the sample volume for measurements of von Mises equivalent stress. Both models were vertically loaded with 750 N, or approximately 1 body weight during a single-leg stance.

RESULTS

All FE models exhibited a physiologically realistic weight-bearing distribution of stress, which initiated at the joint surface and extended to the cortical bone. Models that contained the SBC experienced a nearly two-fold increase in stress (0.934 ± 0.073 and 1.69 ± 0.159 MPa, for the non-SBC and SBC models, respectively) within the bone adjacent to the SBC. In addition, there was a positive correlation found between the diameter of the SBC and the resultant intra-osseous stress under load (p = 0.004).

CONCLUSIONS

Our results provide insights into the mechanism by which SBC may accelerate OA, leading to greater pain and disability. Based on these findings, we feel that patient-derived FE models of the OA knee - utilizing in vivo imaging data - present a tremendous potential for monitoring joint mechanics under physiological loads.

Quantitative assessment of mobile protein levels in human knee synovial fluid: feasibility of chemical exchange saturation transfer (proteinCEST) MRI of osteoarthritis

PURPOSE

To establish the feasibility of chemical exchange saturation transfer (proteinCEST) MRI in the differentiation of osteoarthritis (OA) knee joints from non-OA joints by detecting mobile protein and peptide levels in synovial fluid by determining their relative distribution.

MATERIALS AND METHODS

A total of 25 knees in 11 men and 12 women with knee injuries were imaged using whole knee joint proteinCEST MRI sequence at 3 T. The joint synovial fluid was segmented and the asymmetric magnetization transfer ratio at 3.5 ppm MTR(asym) (3.5 ppm) was calculated to assess protein content in the synovial fluid. The 85th percentile of synovial fluid MTR(asym) (3.5 ppm) distribution profile was compared using the independent Student's t test. The diagnostic performance of the 85th percentile of synovial fluid MTR(asym) (3.5 ppm) in differentiating OA and non-OA knee joints was evaluated.

RESULTS

The 85th percentile of synovial fluid MTR(asym) (3.5 ppm) in knee joints with OA was 8.6%±3.4% and significantly higher than that in the knee joints without OA (6.3%±1.4%, P<.05). A knee joint with an 85th percentile of synovial fluid MTR(asym) (3.5 ppm) greater than 7.7% was considered to be an OA knee joint. With the threshold, the sensitivity, specificity and overall accuracy for differentiating knee joints with OA from the joints without OA were 54% (7/13), 92% (11/12) and 72% (18/25), respectively.

CONCLUSION

proteinCEST MRI appears feasible as a quantitative methodology to determine mobile protein levels in synovial fluid and identify patterns characteristic for OA disease.

How reliable is MRI in diagnosing cartilaginous lesions in patients with first and recurrent lateral patellar dislocations?

BACKGROUND

Lateral dislocation of the patella (LPD) leads to cartilaginous injuries, which have been reported to be associated with retropatellar complaints and the development of patellofemoral osteoarthritis. Therefore, the purpose of this study was to determine the reliability of MRI for cartilage diagnostics after a first and recurrent LPD.

METHODS

After an average of 4.7 days following an acute LPD, 40 patients (21 with first LPDs and 19 with recurrent LPDs) underwent standardized 1.5 Tesla MRI (sagittal T1-TSE, coronal STIR-TSE, transversal fat-suppressed PD-TSE, sagittal fat-suppressed PD-TSE). MRI grading was compared to arthroscopic assessment of the cartilage.

RESULTS

Sensitivities and positive predictive values for grade 3 and 4 lesions were markedly higher in the patient group with first LPDs compared to the group with recurrent LPDs. Similarly, intra- and inter-observer agreement yielded higher kappa values in patients with first LPDs compared to those with recurrent LPDs. All grade 4 lesions affecting the subchondral bone (osteochondral defects), such as a fissuring or erosion, were correctly assessed on MRI.

CONCLUSIONS

This study demonstrated a comparatively good diagnostic performance for MRI in the evaluation of first and recurrent LPDs, and we therefore recommend MRI for the cartilage assessment after a LPD.