Coracoclavicular bursal changes on MRI: a diagnostic consideration in patients with shoulder pain and reduced coracoclavicular distance.

OBJECTIVE: To describe MRI changes of the coracoclavicular bursa in patients presenting with shoulder pain and examine whether there is an association with coracoclavicular distance measurements. METHODS: Retrospective analysis of 198 shoulder 3T MRI scans for patients with shoulder pain was performed. Two musculoskeletal trained radiologists read all MRI scans. Inter-reader and intra-reader agreements for the bursal changes were assessed using the Kappa coefficient. The coracoclavicular distance was stratified into three intervals: < 5 mm, 5-10 mm, and > 10 mm. Statistical analysis for the coracoclavicular bursal changes and coracoclavicular distance was conducted using Fisher's exact test. RESULTS: Coracoclavicular bursal changes were detected in 9% (n = 18/198) of patients. There was a statistically significant association between coracoclavicular distance (< 5 mm) and the presence of coracoclavicular bursal changes (p-value = 0.011). All patients (100%, n = 18/18) with coracoclavicular bursal fluid presented with shoulder pain with 44.5% of the patients (n = 8/18) describing anterior shoulder pain. A statistically significant association was detected between coracoclavicular bursal changes and anterior shoulder pain (p-value = 0.0011). Kappa coefficient for the bursal changes inter-reader agreement was moderate (0.67) and the intra-reader agreement was almost perfect (0.91). CONCLUSION: Coracoclavicular bursal changes were detected in 9% of shoulder MRI scans and were associated with reduced coracoclavicular distance (< 5 mm) suggesting an underlying mechanical disorder such as a friction or an impingement process. Documenting coracoclavicular bursal changes in the MRI report could help address patients' concerns and guide further management particularly in the context of shoulder pain and coracoclavicular distance of less than 5 mm.

Bone-cartilage mismatch in the medial tibial plateau: A MRI study.

BACKGROUND: Bone-cartilage mismatch is a variation in which the surface curvature of the articular cartilage is incongruent with the curvature of the underlying subchondral bone. The purpose of this study is to investigate the prevalence of this variant in the medial tibial plateau (MTP) and examine potential association with clinical findings and intra-articular derangements using MRI. METHODS: A quantitative and qualitative retrospective analysis of 98 knee MRI studies was performed. Bone and cartilage depths of the MTP were measured to assess bone-cartilage morphology and classified into congruent (concave bone-concave cartilage) and incongruent (concave bone-convex cartilage) patterns. Associations between bone-cartilage mismatch and clinical findings and other MRI changes were assessed using Fisher's exact test. RESULTS: By quantitative assessment, four individuals (4%) had MTP incongruent morphology (bone-cartilage mismatch). The mean bone depth ± standard deviation (SD) was 2.3 ± 0.6 mm concave in the congruent group, and 1.4 ± 0.6 mm concave in the incongruent group. The mean cartilage depth ± SD was 0.7 ± 0.7 mm concave in the congruent group, and 0.9 ± 0.5 mm convex in the incongruent group. By qualitative assessment, three individuals (3%) had incongruent morphology. Although not statistically significant, a higher proportion of individuals (3 of 4; 75%) with incongruent cartilage demonstrated chondromalacia patellae compared to those with congruent cartilage (38 of 94; 40%). CONCLUSION: Bone-cartilage mismatch was present in 3-4% of the knees. Individuals with incongruent cartilage demonstrated a trend of a higher proportion of chondromalacia patellae. Larger studies are needed to evaluate this further.

Posterior ankle labral changes at MRI: A preliminary study.

INTRODUCTION: The transverse ligament in the ankle joint has been described as a labrum-like structure in a previous cadaveric study. The purpose of this study is to assess the spectrum of abnormal changes related to this structure on imaging/MRI, and correlate these findings with other ankle joint findings and patient symptoms. METHOD: A retrospective observational review of 172 ankle MRI scans was carried out independently by two fellowship trained musculoskeletal Radiologists. Correlation between abnormal labral changes, other ankle joint findings and patient symptomatology was performed. RESULTS: Abnormal labral changes were seen in 26% of the MRI scans (n = 44/172) and included signal change, contour abnormality with heterogeneous signal change, linear fluid filled clefts, multidirectional fluid filled clefts, and a macerated labrum. There was a statistically significant association between abnormal labral changes and the presence of Stieda process/os trigonum (P = 0.001), talocrural joint osteoarthritis (P = 0.0003), paralabral cysts (P = 0.0001), imaging features of posterior impingement (P = 0.01), and both medial (P = 0.005) and lateral (P = 0.01) ankle ligament injuries. However, there was no statistically significant association between abnormal labral changes and patient symptoms. CONCLUSION: The posterior ankle labrum can develop a spectrum of abnormal MRI appearances in patients with other ankle joint abnormalities. Although this study showed no correlation between patients' symptoms and posterior ankle labral changes, larger studies are needed to examine the biomechanical alterations that may arise from these labral changes.

Acetabular anteversion is associated with gluteal tendinopathy at MRI.

OBJECTIVE: Gluteal tendinopathy and greater trochanteric pain syndrome (GTPS) remain incompletely understood despite their pervasiveness in clinical practice. To date, no study has analyzed the morphometric characteristics of the hip on magnetic resonance imaging (MRI) that may predispose to gluteal tendinopathy. This study aimed to evaluate whether acetabular anteversion (AA), femoral neck anteversion (FNA), and femoral neck-shaft angle (FNSA) are associated with MRI features of gluteal tendinopathy. MATERIALS AND METHODS: A total of 203 MRI examinations of the hip met our inclusion and exclusion criteria. A single blinded investigator measured AA, FNA, and FNSA according to validated MRI techniques. Two blinded subspecialty-trained musculoskeletal radiologists then independently evaluated the presence of gluteal tendinosis, trochanteric bursitis, and subgluteal bursitis. Statistical analysis was performed using a one-way analysis of variance (ANOVA; post-hoc Tukey's range test). RESULTS: At MRI, 57 patients had gluteal tendinosis with or without bursitis, 26 had isolated trochanteric bursitis, and 11 had isolated subgluteal bursitis. AA was significantly (p = 0.01) increased in patients with MRI evidence of gluteal tendinosis with or without bursitis [mean: 18.4°, 95 % confidence interval (CI): 17.2°-19.6°] compared with normal controls (mean: 15.7°, 95 % CI: 14.7°-16.8°). Similarly, AA was significantly (p = 0.04) increased in patients with isolated trochanteric bursitis (mean: 18.8°, 95 % CI: 16.2°-21.6°). No association was found between FNA or FNSA and the presence of gluteal tendinopathy. Interobserver agreement for the presence and categorization of gluteal tendinopathy was very good (kappa = 0.859, 95 % CI: 0.815-0.903). CONCLUSION: Our MRI study suggests that there is an association between increased AA and gluteal tendinopathy, which supports a growing body of evidence implicating abnormal biomechanics in the development of this condition.

Increasing lateral tibial slope: is there an association with articular cartilage changes in the knee?

PURPOSE: The geometry of the lateral tibial slope (LTS) plays an important role in the overall biomechanics of the knee. Through this study, we aim to assess the impact of LTS on cartilage degeneration in the knee. MATERIALS AND METHODS: A retrospective analysis of 93 knee MRI scans (1.5 T or 3 T) for patients aged 20-45 years with no history of trauma or knee surgery, and absence of internal derangement. The LTS was calculated using the circle method. Chondropathy was graded from 0 (normal) to 3 (severe). Linear regression analysis was used for statistical analysis (p < 0.05). RESULTS: In our cohort of patients, a statistically significant association was seen between increasing LTS and worsening cartilage degenerative changes in the medial patellar articular surface and the lateral tibial articular surface (p < 0.05). There was no statistically significant association between increasing LTS and worsening chondropathy of the lateral patellar, medial trochlea, lateral trochlea, medial femoral, lateral femoral, and medial tibial articular surfaces. CONCLUSIONS: Our results show a statistically significant association between increasing LTS and worsening cartilage degenerative changes in the medial patella and the lateral tibial plateau. We speculate that increased LTS may result in increased femoral glide over the lateral tibial plateau with subsequent increased external rotation of the femur predisposing to patellofemoral articular changes. Future arthroscopic studies are needed to further confirm our findings.

Interaction of Yersinia enterocolitica and Y. pseudotuberculosis with platelets.

Yersinia enterocolitica is a bacterium capable of growth at 4 degrees C in donated blood and has been responsible for many deaths following transfusion. Interaction of Y. enterocolitica with blood cells is of interest in understanding the mechanisms of survival and growth in blood. The closely related organism Y. pseudotuberculosis is known to invade platelets and cause platelet aggregation by a mechanism that involves expression of the chromosomal inv gene. Yersinia isolates were made to express green fluorescent protein (GFP) and their interaction with platelets was studied by flow cytometry, enterocolitica did not cause platelet aggregation or activation, not even when grown at 22 degrees C to maximise inv expression. Attachment of Y. enterocolitica O:9 to platelets occurred with virulence plasmid-bearing (pYV+) strains grown at 37 degrees C but not with pYV- strains nor with strains grown at 22 degrees C. Y. pseudotuberculosis containing inv did cause platelet activation and aggregation when grown at 22 degrees C, as has been shown before, but also showed enhanced attachment to platelets when grown at 37 degrees C. Electron microscopy studies confirmed that inv-expressing Y. pseudotuberculosis invaded platelets but Y. enterocolitica attached only to the outer surface of platelets. Interaction of Y. enterocolitica O:9 with platelets provided a modest protection against bacterial killing by human serum. Interaction of Y. enterocolitica O:9 with platelets does not lead to platelet invasion or activation, and is mediated through plasmid-coded factors, not inv.