Development of a scoring method to visually score cortical interruptions on high-resolution peripheral quantitative computed tomography in rheumatoid arthritis and healthy controls.

OBJECTIVES: To develop a scoring method to visually score cortical interruptions in finger joints on High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT), determine its intra- and inter-reader reliability and test its feasibility. METHODS: The scoring method was developed by integrating results from in-depth discussions with experts, consensus meetings, multiple reading experiments and the literature. Cortical interruptions were scored by two independent readers in an imaging dataset with finger joints from patients with rheumatoid arthritis (RA) and healthy controls and assessed for adjacent trabecular distortion. Reliability for the total number of cortical interruptions per joint and per quadrant was calculated using intraclass correlation coefficient (ICC). Feasibility was tested by recording the time to analyze one joint. RESULTS: In 98 joints we identified 252 cortical interruptions, 17% had trabecular distortion. Mean diameter of the interruptions was significantly larger in patients with RA compared with healthy controls (0.88 vs 0.47 mm, p = 0.03). Intra-reader reliability was ICC 0.88 (95% CI 0.83;0.92) per joint and ICC 0.69 (95% CI 0.65;0.73) per quadrant. Inter-reader reliability was ICC 0.48 (95% CI 0.20;0.67) per joint and ICC 0.56 (95% CI 0.49;0.62) per quadrant. The time to score one joint was mean 9.2 (SD 4.9) min. CONCLUSIONS: This scoring method allows detection of small cortical interruptions on HR-pQCT imaging of finger joints, which is promising for use in clinical studies.

Comparison of tests for lumbar flexion and hip function in patients with and without axial spondyloarthritis.

OBJECTIVE: To compare the 15-cm Schober test with the 10-cm Schober test and the intermalleolar distance (IMD) with the internal hip rotation (IHR). METHODS: A cross-sectional study was conducted among both healthy individuals and patients with axial spondyloarthritis (SpA).The spinal and hip mobility tests were assessed in all subjects. Agreement between the different tests was assessed with correlation coefficients, Bland and Altman agreement, and by cumulative probability plots. The component scores for lumbar flexion in the Bath Ankylosing Spondylitis Metrology Index (BASMI) with use of either the 10-cm Schober test or the 15-cm Schober test were compared. RESULTS: A total of 393 healthy individuals (51% males; mean age 44 years) and 90 patients with axial SpA (53% males; mean age 49 years) were included. A strong correlation was found between the 10-cm and 15-cm Schober test, in both healthy individuals (r = 0.89) and in patients (r = 0.93). The 10-cm Schober test was systematically lower than the 15-cm test with a mean ± SD difference of 1.5 ± 0.8 cm in patients, resulting in a higher total mean ± SD BASMI score of 0.4 ± 0.2 points. The correlation between IMD and IRH was weak, both in healthy individuals (r = 0.29) and in patients (r = 0.40). CONCLUSION: The 10-cm and 15-cm Schober tests are highly correlated but, as expected, the 10-cm method is systematically lower than the 15-cm method. Therefore, these measures cannot be interchangeably used in the BASMI. The IMD and IHR are not correlated, indicating that they measure different aspects of hip mobility. Therefore, the IHR cannot be used as a substitute for the IMD.

The prevalence of vertebral fractures in spondyloarthritis: relation to disease characteristics, bone mineral density, syndesmophytes and history of back pain and trauma.

INTRODUCTION: An increased risk of vertebral fracture (VF) is one of the extra-articular manifestations of spondyloarthropathy (SpA). The prevalence of moderate to severe VFs visualized by radiography (Rx) in patients with SpA in daily practice is unknown until imaging of the full spine is available, as most VFs do not present with clinical signs and symptoms of an acute fracture. METHODS: We evaluated the prevalence of VFs (>25% loss in height) on available Rx and dual-energy X-ray absorptiometry (DXA) images in 390 consecutive patients with SpA in daily practice. We assessed their association with disease characteristics, bone mineral density, the modified Stoke Ankylosing Spondylitis Spinal Score, and history of trauma. RESULTS: Forty-six patients (11.8%) had Rx VF (56.4% men, 93.5% in the thoracic spine), and 44.5% had multiple VFs. Compared with patients without VF, patients with VF were older (52.2 vs. 47.3 years, p < 0.01; range 25-84 years), had lower femoral neck T-scores (-1.1 vs. -0.7; p < 0.05), and had a marginally higher modified Stoke Ankylosing Spondylitis Spinal Score (11.7 vs. 7.0; p = 0.06). Among patients with VFs, 15.2% had a history of trauma with acute back pain (p < 0.001 vs. no VF). The reliability of DXA for diagnosing radiographic VFs was high (κ 0.90). CONCLUSIONS: Moderate to severe VFs are found in more than 10% of patients with SpA before the age of 40 years in 5% of women and 9% in men. Most VFs are located in the thoracic region, are related to low femoral neck bone mineral density and to stiffening of the spine, and are only rarely related to trauma history. DXA is a useful alternative for diagnosing VFs.

Osteoporosis and vertebral fractures in ankylosing spondylitis.

PURPOSE OF REVIEW: To review recent data, in the context of what is already known, about an increased risk of vertebral fractures in ankylosing spondylitis patients. RECENT FINDINGS: Osteoporosis and fractures of the vertebral body and its dorsal arch are now well recognized features in patients with ankylosing spondylitis, but their diagnosis is still often a challenge. The risk factors and clinical consequences for fractures in ankylosing spondylitis are increasingly understood in the context of osteoimmunology and of spinal biomechanical changes in material and structural components in the spine that result in bone failure. SUMMARY: Diagnosing fractures of the vertebral body and its dorsal arch remains a challenge in studies and in clinical practice. Prospective studies are needed to evaluate to what degree such fractures can be prevented in ankylosing spondylitis.

Prevalence and annual incidence of vertebral fractures in patients with ankylosing spondylitis.

OBJECTIVES: To evaluate the prevalence and annual incidence of clinically-manifest vertebral fractures among patients with ankylosing spondylitis (AS). METHOD: Coordinated by the Ankylosing Spondylitis International Federation, a self-administered general questionnaire which included some questions on gender, age, age at onset of disease, and a history of vertebral fracture was inserted in one issue of the membership journals of the AS patient organizations in Germany and Austria. RESULTS: Among the 1,071 patients responding who all had indicated that the diagnosis of AS had been established or confirmed by a physician, 61 (5.7%) indicated a history of vertebral fracture, 15 of them (1.4%) without an accident. The prevalence of vertebral fractures was 6.2% among male AS patients and 4.6% among females (NS), and 4.8% among HLA-B27+ patients and 9.9% among HLA-B27(-) patients (p<0.05). Spinal fractures occurred more often among AS patients with peripheral arthritis (7.1%) than among patients with axial involvement only (3.1%, p<0.01). The average delay between disease onset and diagnosis of AS was 10.5 years for patients with a vertebral fracture, compared to 8.7 years for patients without any such event (p<0.05). Among patients with a disease duration >or=42 years, the prevalence of vertebral fractures was 14%. The annual incidence of vertebral fractures which occurred without an accident had a maximum of 0.1% per annum at a disease duration of 20-35 years, whereas the incidence of vertebral fractures caused by an accident increased continuously with increasing disease duration, amounting to 1.3% per annum after a disease duration of 45 years. CONCLUSION: A considerable proportion of AS patients will experience a vertebral fracture during the course of the disease, in particular if peripheral joints are also involved.

Clinical vertebral fractures in patients with ankylosing spondylitis.

OBJECTIVE: To evaluate the prevalence and characteristics of clinically confirmed vertebral fractures (CVF) in patients with ankylosing spondylitis (AS). METHODS: Coordinated by the Ankylosing Spondylitis International Federation in Germany and in Denmark, a self-administered questionnaire was sent to all their members about age, diagnosis, disease duration, HLA-B27 status, and history of CVF. Patients who were aware of having had a CVF were asked to return the questionnaire with additional specification of the location of CVF, associated trauma, neurological complications, therapy for these complications, and recovery. We also reviewed available radiographs. RESULTS: Out of 15,097 questionnaires, 59 patients (0.4%) reporting 66 CVF returned the complete questionnaire (46 men, 13 women). Mean age at fracture was 50 +/- 9 years, after a mean duration of symptoms of 26 +/- 11 years. CVF with wedging or crush or transverse fracture were reported in the cervical (n = 21, 36%), thoracic (n = 21, 36%), and lumbar spine (n = 16, 27%), with one unspecified. In 37 fractures (56%), patients reported no/low or medium trauma in relation to the fracture. In 31 fractures (47%), patients reported neurological complications, occurring mostly without trauma (n = 11, 35%) or after minimal trauma (n = 7, 23%). Twenty (65%) of these patients did not have full neurological recovery. CONCLUSION: We found that 0.4% of patients with AS reported CVF at a mean age of 50 years, occurring after 2 decades of disease, mainly without trauma or after minimal trauma, with frequent neurological complications mostly followed by incomplete neurological recovery.

Measurement of spinal mobility in ankylosing spondylitis: comparison of occiput-to-wall and tragus-to-wall distance.

OBJECTIVE: To investigate if the tragus-to-wall distance (TWD) is more reliable compared to the occiput-to-wall distance (OWD) as a measurement for thoracic spine extension in patients with ankylosing spondylitis (AS). METHODS: Data from the OASIS cohort, an international longitudinal observational study on outcome in AS, were used. Measurements of OWD and TWD were performed at baseline and at 6, 12, 18, and 24 months. Paired data of Tx and Tx+6 months were used to perform test-retest measurements (intraclass correlations, limits of agreement, and interperiod correlation matrix). Bland and Altman plots were constructed to investigate the agreement between both observations, assuming that there was no true change between 0 and 6 months. To investigate whether a change in disease activity would have influenced the results, limits of agreement were calculated in a subgroup of patients with a stable Bath Ankylosing Spondylitis Disease Activity Index (BASDAI; defined as a maximum BASDAI change of +/- 1) between T0 and T6 and compared with the results of the whole group. Limits of agreement were also calculated for kyphosed patients only. RESULTS: The test-retest intraclass correlations were between 0.94 and 0.96 for OWD and between 0.93 and 0.95 for TWD. The direct measurement-remeasurement correlation calculated by extrapolation of the interperiod correlation regression line was 0.92 for OWD and 0.90 for TWD. OWD and TWD showed comparable reliability on the entire value of scores. The lower 95% limit of agreement was between -3.4 cm and -2.5 cm for OWD and between -3.4 cm and -3.1 cm for TWD. The upper limit of agreement was between 3.1 cm and 4.2 cm for OWD and between 2.9 cm and 3.9 cm for TWD. In all patients as well as in kyphosed patients only, limits of agreement were comparable between OWD and TWD. The patterns of the scatterplots according to Bland and Altman were similar for OWD and TWD. Measurement error was more pronounced in kyphosed patients compared to patients with a normal thoracic extension. However, over the entire range of kyphosis, measurement error was similar. CONCLUSION: OWD and TWD are equally reliable in assessing thoracic spine extension. Although the TWD is in general easier to perform in AS patients compared to OWD, we recommend the OWD measurement over TWD: in OWD measurement a value of zero easily distinguishes patients with normal thoracic spine extension from kyphosed patients.