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The article presents a study which examines the microanatomic factors that could contribute to the topography of erosion formation in arthritis. In this study, patients with rheumatoid arthritis were assessed by computed tomography to ascertain whether the topography of their erosion formation corresponds to the result of the histologic analysis of cadaveric ligaments. Result suggests that periligamentous locations prone to microdamage influence the topography of erosion formation in arthritis.

OBJECTIVE: This study combined ultrasonography of the Achilles tendon enthesis at different stages of spondylarthritis (SpA) with microanatomic studies of normal cadaveric entheses, with the aim of exploring the relationship between bone erosion and new bone formation in enthesitis. METHODS: Thirty-seven patients with SpA and Achilles tendon enthesitis (20 with early SpA and 17 with chronic SpA) and 10 normal control subjects underwent ultrasound scanning. The presence of bone erosion and spur formation was recorded at 3 sites: the proximal and distal halves of the enthesis and the adjacent calcaneal superior tuberosity. Parallel histologic analysis was performed on cadaveric Achilles tendon entheses to determine whether regional variations in bone density and trabecular architecture in relation to fibrocartilage distribution are related to disease patterns. RESULTS: Bone erosion in patients with early SpA occurred at either the proximal insertion or the superior tuberosity (11 of 20 patients; P < 0.001 versus distal enthesis). Very small spurs, which were present almost exclusively at the distal enthesis, were evident in patients with early SpA and in normal control subjects. However, large spurs were evident distally only in patients with chronic SpA (9 of 17 patients, compared with none of 20 patients with early SpA; P < 0.0001). Histologic studies showed that aged normal individuals had small spurs at the corresponding location. The bone-to-marrow ratio was also significantly lower in the regions prone to erosions (P < 0.05). CONCLUSION: Bone erosion in association with Achilles tendon enthesitis in SpA is anatomically uncoupled from bone formation-the 2 processes are topographically and temporally distinct. We thus conclude that disease patterns in SpA are related to normal enthesis structure and biomechanics. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Distal interphalangeal (DIP) joint arthropathy is characteristic of both psoriatic arthritis (PsA) and osteoarthritis (OA), but the microanatomic basis for DIP joint localization is poorly understood. This study used high-resolution magnetic resonance imaging (MRI) to investigate the basis for hand disease localization in both conditions. METHODS: Twenty patients matched for disease duration (10 with DIP joint PsA and 10 with DIP joint OA) and 10 normal control subjects were scanned with a 1.5T MRI scanner utilizing a high-resolution 23-mm diameter surface coil with displayed pixel dimensions of 80-100 mum. Images were obtained precontrast and postcontrast, and all joint structures, including ligaments, tendons, and entheses, were evaluated by 2 independent assessors. RESULTS: PsA could be distinguished from OA on the basis of more severe inflammation in the collateral ligaments and the extensor tendons and more severe changes at the corresponding DIP joint entheseal insertions. A much greater degree of extracapsular enhancement, with diffuse involvement of the nailbed and diffuse bone edema without cartilage damage, was also typical of PsA. Compared with the normal controls, the OA cohort exhibited prominent ligament and entheseal changes, but with much less contrast enhancement than in PsA and less bone involvement at the insertions. CONCLUSION: These findings suggest prominent inflammatory changes in ligament, tendon, enthesis, and adjacent bone in the DIP joint disease of PsA patients. Involvement of the same structures is common in the DIP joints of OA patients, but inflammatory changes are much less marked. These findings are potentially important for a better understanding of arthritis in humans. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the use of a novel surface coil for clinically utilized magnetic resonance imaging (MRI) scanners, in order to describe the microanatomic basis for hand osteoarthritis (OA) at all stages of disease. METHODS: MRI of proximal or distal interphalangeal joints was performed in 58 subjects: 16 patients with early OA (symptom duration < or =12 months), 14 patients with chronic OA, 10 patients with clinically normal asymptomatic joints adjacent to arthritic joints, and 18 normal controls. High-resolution images were obtained with displayed pixel dimensions of 80-100 mum using a 1.5T scanner and a 23-mm-diameter surface coil. All joint structures were evaluated. RESULTS: The high-resolution images of every joint structure showed comparable abnormalities in both early and chronic OA, including cartilage loss, bone edema, synovial enhancement, osteophytosis, and erosions. Heberden's and Bouchard's node formation occurred at regions where soft tissue bulged through the capsule between the dorsal tendons and collateral ligaments (CLs). Prominent CL thickening or disruption (100% of OA patients) was evident even in joints where cartilage was partially preserved. Clinically normal joints adjacent to OA hand joints showed thickening and enhancement of CLs which was the most common abnormality seen (80% of OA patients). Older normal subjects showed subtle changes within the CLs. CONCLUSION: Obtaining high-resolution MR images from clinically utilized scanners represents a novel way for exploring the microanatomic basis of hand arthritis and may have considerable potential in the clinical setting. In the present evaluation in nodal OA, previously unappreciated CL abnormalities were especially common. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To use magnetic resonance imaging (MRI) to investigate the importance of knee joint synovitis at the cartilage-pannus junction (CPJ) in rheumatoid arthritis (RA) as compared with synovitis at a distant site in the suprapatellar pouch (SPP) and as compared with CPJ synovitis in the spondylarthropathies (SpA), and to assess the relative response of knee joint synovitis to therapy at the CPJ and SPP sites. METHODS: Dynamic contrast-enhanced MRI (DEMRI) of actively involved knee joints in 24 patients (13 with RA and 11 with SpA) was undertaken. The area of synovitis was calculated at the CPJ and SPP regions of interest in patients with RA and in patients with SpA. Differences in CPJ and SPP synovitis were determined using calculated DEMRI parameters which included the initial rate of contrast enhancement (IRE) and the maximal enhancement (ME). Changes in the synovial area at the CPJ and SPP were also measured in 10 patients with early RA, following treatment with disease-modifying antirheumatic drugs (DMARDs) (either methotrexate or leflunomide). RESULTS: In patients with RA or SpA, the area of synovitis was significantly larger immediately adjacent to the CPJ compared with a distant site at the SPP (in RA, mean synovitis area 162 mm2 at the CPJ versus 114 mm2 at the SPP [P = 0.010]; in SpA, mean synovitis area 214 mm2 at the CPJ versus 143 mm2 at the SPP [P = 0.002]), but the differences in the areas of synovitis at these sites were not significant between the RA and SpA patients. The IRE and ME values were also higher at the CPJ compared with the SPP, both in the RA patients (IRE P = 0.054, ME P = 0.018) and in the SpA patients (IRE P = 0.002, ME P = 0.001). A larger reduction in the area of synovitis was seen at the SPP compared with the CPJ following DMARD therapy in the RA patients (mean reduction 35% at the SPP [P = 0.023] and 12% at the CPJ [P not significant]). CONCLUSION: The non-disease-specific variations in synovitis and the differential responses to therapy in RA patients have implications for improving our understanding of CPJ synovitis. The results suggest that the pathophysiologic events at the CPJ reflect common anatomic, immune system, or biomechanical factors that play a role in modulating the severity of arthritis, and these events are not specific to RA since the same process was observed in other arthritides. [ABSTRACT FROM AUTHOR]