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Musculoskeletal measurement tools from the International Prophylaxis Study Group (IPSG )

2008; Wiley; Volume: 14; Issue: s3 Linguagem: Inglês

10.1111/j.1365-2516.2008.01750.x

1365-2516

B. M. Feldman, Sharon Funk, Björn Lundin, Andréa S. Doria, Rolf Ljung, Victor S. Blanchette,

Blood Coagulation and Thrombosis Mechanisms

Haemophilia is a sex-linked inherited disorder caused by deficiencies of coagulation factor VIII (haemophilia A) or IX (haemophilia B) [1]. The disorder occurs in all ethnic groups with an estimated frequency of 1 per 5–10 000 live male births. The ratio of haemophilia A to B cases is approximately 4:1. Traditionally, the haemophilias are classified as severe, moderate or mild based on circulating factor levels 5%, respectively. In many European centres a factor level of 1/3 of the surface), subchondral cystic defects within the lateral aspect of the distal tibial epiphysis surrounded by bone marrow oedema and joint space narrowing. The MR images received a score of 10 as per the P scale and a score of 16 as per the A scale which constitute the maximum scores for the osteochondral domain of the scales. No associated soft tissue changes were noted. Radiographic scales: Petterson scale -> enlargement of epiphysis (=1), pronounced irregularity of subchondral surface (=2), >50% narrowing of joint space (=2), >1 subchondral cyst (=2), presence of erosions at joint margins (=1). Arnold-Hilgartner scale = narrowing of the joint space and cartilage destruction (=4). Compatible MRI scales: P scale -> maximum changes of subchondral bone or joint margins (=8), maximum cartilage loss (=10). A scale -> maximum changes of subchondral bone or joint margins (=8), maximum cartilage loss (=8). First, the clinimetric properties of the original progressive Denver [28] and additive European [23] MRI scales were investigated for knees and ankles. Four experienced radiologists reviewed 47 MRI examinations performed at three centres on 1.5 Tesla scanners. For all examinations gradient-echo sequences, which enable visualization of the articular cartilage, fluid and haemosiderin deposition, were available. The ability to detect haemosiderin relates to the visualization of susceptibility artefacts caused by extracellular haemosiderin within soft tissues seen especially well on gradient echo images. The results demonstrated that the two MRI scoring systems had comparable inter- and intra-reader reliability [29]. However, it was still not known whether a progressive or additive scoring method was the most expedient, nor what level of detail was feasible and necessary to meet clinical and scientific needs. Thus, to initiate standardization, and to facilitate further evaluation, a preliminary single MRI scoring scheme (the 'compatible' MRI scales) was derived from the original Denver and European MRI scales. Second, the Expert Imaging Group tested the reliability and construct validity of the compatible MRI scale for evaluation of hemophilic knees, ankle, and elbows, and compared the diagnostic performance of MRI and plain film radiographs for assessment of these joints. For the investigation of knees and ankles, 1.5 Tesla MR images of 22 knees and 23 ankles – from boys 4 to 16 years old – were reviewed by four blinded radiologists on two occasions [30]. The number of previous joint bleeds and severity of haemophilia were considered reference standards. Both the progressive and the additive components of the compatible scale demonstrated high inter- and intra-reader reliability. With regard to convergent validity, the correlation between the MRI scale osteochondral domain and patients' age was moderate (0.60 ≥ r > 0.40). Otherwise, correlations between additive and progressive sub-scales and clinical laboratory measurements were modest (r ≤ 0.40). With regard to discriminant validity of the MRI and radiographic scales (Arnold-Hilgartner and Pettersson), no differences were noted between the accuracy (excellent, area-under-the-curve – AUC > 0.80) for late osteoarticular changes. The MRI scales performed better for discrimination of early joint changes, however, at a borderline level for diagnostic performance (AUC for the additive sub-scale = 0.72 and for the progressive sub-scale = 0.69). With regard to the assessment of elbows, 29 MR examinations of elbows from 27 haemophilic boys (age 5–17 years) were reviewed by four experienced radiologists. In this study, the inter-reader reliability of MRI scores was substantial (intraclass correlation coefficients – 0.80 ≥ ICC > 0.60) for the additive sub-scale and excellent (ICC > 0.80) for the progressive sub-scale; the intra-reader reliability was excellent for both progressive and additive sub-scores. The MRI scores correlated modestly to moderately with clinical and laboratory parameters (severity of haemophilia); however, a number of subjects with severe haemophilia had been managed on long-term prophylaxis, essentially converting them to the moderate haemophilic phenotype. In conclusion, we noticed that the compatible MRI scales were highly reliable, but may not be as good at detecting osteo-articular changes, especially at the elbows. Third, based on experience gained by the use of this scoring scheme as well as other previous MRI scales [11,21–25,29–33], a single 16 step additive MRI scale for haemophilic arthropathy was developed. In this optimized MRI scale, soft tissue changes were given more weight with the aim of improving the detection of early soft tissue changes. Also, the number of items in the osteochondral domain was reduced, and, in addition, the final score for soft tissue changes and for osteochondral changes are displayed separately. The use of one single MRI scale will facilitate international comparison of data. A report of the Expert Imaging Working Group including the new optimized scale and recommendations on technical requirements for minimum imaging protocols for MRI assessment of haemophilic arthropathy will be submitted for publication. The IPSG Expert PT and Imaging Working Groups have developed and tested new tools for the evaluation of musculoskeletal changes in children with haemophilia. These new tools are especially suited for use in young boys with severe haemophilia who are placed on programs of primary prophylaxis. They will serve as important outcome measures in future prospective studies of both primary and secondary prophylaxis. They will also have a role in the assessment and follow-up of patients who undergo procedures such as radiosynovectomy. Future goals of the Expert PT and Imaging Working Groups of the IPSG will be to design and evaluate practical protocols for clinical use of these new tools, and to compare MRI with ultrasound for assessment of musculoskeletal disease in persons with haemophilia. Activities of the International Prophylaxis Study Group are supported by unrestricted grants from Bayer HealthCare LLC, Biological Products Division; Baxter BioScience; Wyeth Pharmaceuticals; and CLS Behring that is administered through the Hospital for Sick Children Foundation, Toronto, Canada. We would also like to acknowledge the Bayer Hemophilia Awards Program for their support of the Hemophilia Joint Health Score validation study. IPSG Steering Committee: Dr Victor Blanchette, Chair (Canada) Dr Louis Aledort, Co-Chair (USA) Dr Rolf Ljung, Co-Chair (Sweden) Dr Brian Feldman (Canada) Dr Alessandro Gringeri (Italy) Dr Marilyn Manco-Johnson (USA) Dr Pia Petrini (Sweden) Dr Georges Rivard (Canada) Dr Wolfgang Schramm (Germany) Dr Marijke van den Berg (The Netherlands) Coordinator: Ms Marjorie McLimont (Canada) Physical Therapy Expert Working Group: Dr Marilyn Manco-Johnson, Paediatric Haematologist, Co-Chair (USA) Dr Pia Petrini, Paediatric Haematologist, Co-Chair (Sweden) Ms Britt-Marie Bergstrom, Physiotherapist (Sweden) Dr Raoul Engelbert, Physiotherapist (The Netherlands) Dr Brian Feldman, Paediatric Rheumatologist (Canada) Ms Sharon Funk, Physiotherapist (USA) Ms Pamela Hilliard, Physiotherapist (Canada) Dr Janjaap van der Net, Physiotherapist (The Netherlands) Dr Marijke van den Berg, Haematologist (The Netherlands) Mr Nichan Zourikian, Physiotherapist (Canada) Imaging Expert Working Group: Dr Andrea Doria, Radiologist, Co-Chair (Canada) Dr Bjorn Lundin, Radiologist, Co-Chair (Sweden) Dr Paul Babyn, Radiologist (Canada) Dr Amy Dunn, Paediatric Haematologist (USA) Dr Georges Rivard, Haematologist (Canada) Dr Holger Pettersson, Radiologist (Sweden) Dr Ray Kilcoyne [deceased] See following page.