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dc.contributor.authorDiamond, LE
dc.contributor.authorMurphy, NJ
dc.contributor.authorEyles, J
dc.contributor.authorKim, Y-J
dc.contributor.authorLinklater, JM
dc.contributor.authorSpiers, L
dc.contributor.authorHunter, D
dc.date.accessioned2021-03-18T01:12:52Z
dc.date.available2021-03-18T01:12:52Z
dc.date.issued2018
dc.identifier.issn1063-4584
dc.identifier.doi10.1016/j.joca.2018.02.847
dc.identifier.urihttp://hdl.handle.net/10072/403253
dc.description.abstractPurpose: Femoroacetabular impingement (FAI) syndrome is a common cause of hip pain in active young adults and a primary contributor to the future development of hip osteoarthritis. FAI morphology is characterised by abnormally shaped hip bones, which can lead to mechanical impingement during movement. Diagnostic imaging is considered essential for the identification of FAI morphology; however precise diagnostic criteria remain elusive. The alpha angle is used universally to assess asphericity at the femoral head-neck junction. However, it is plagued by modest repeatability, fickle thresholds, and poor specificity of subsequent symptomatic and structural decline. An anatomical measurement that accounts for not only the aberrant femoral head, but also the acetabular shape and proximity, may better characterise the potential for mechanical impingement. The beta angle describes the angle between the femoral head-neck junction and the acetabular rim. It has been the subject of few investigations despite its potential relevance. This study aimed to determine: (1) reliability and measurement error of beta and alpha angle measurements in four radial reformatted planes on magnetic resonance image (MRI); and (2) associations of beta and alpha angle measurements with cartilage health. Methods: Twenty-seven participants (age = 28.8 ± 8.6 yrs; BMI = 24.2 ± 2.3 kg m−2; 44% females) diagnosed with FAI syndrome (cam-, pincer- or combined-type FAI morphology concurrent with symptoms) underwent hip MRI with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) in one of two 3T scanners (Siemens Prisma, Siemens Skyra). The dGEMRIC scanning protocol used inversion recovery sequences acquired in the sagittal plane; scores were calculated over a 1cm region of interest encompassing acetabular and femoral head cartilage in three mid-sagittal slices at the chondrolabral junction. Beta and alpha angles (Fig.1) were measured in four radial reformatted planes at 30° intervals: (1) superior; (2) superoanterior; (3) anterosuperior; and (4) anterior. Relative inter- and intra-rater reliability were estimated for a randomly selected subset of 19 participants; the optimal intra-class correlation coefficients (ICC) defined a priori was 0.90. Reliability measures were calculated using ICC2,1 with 95% confidence intervals for a 2-way random effects model and absolute agreement. Absolute reliability was calculated using standard error of measurement (SEM) and minimal detectable change (MDC). Associations between angular measures and dGEMRIC scores were assessed using Pearson’s correlation coefficient (r). Results: Reliability was optimal (ICC > 0.9) for beta angle measures and good (0.75 > ICC > 0.90) for alpha angle measures both between- and within-raters (Table 1). Measurement error was higher for beta angle than alpha angle between- (SEM = 14.4% vs 8.6%) and within- raters (SEM = 16.4% vs 8.9%). Minimum beta angles and maximum alpha angles most commonly occurred in the superoanterior plane (50%; 38%). Minimum beta angle and maximum alpha angle were significantly associated with dGEMRIC scores (r = 0.518, P < 0.01; r = −0.511, P < 0.01). Conclusions: The beta angle demonstrated superior reliability but greater measurement error compared to the alpha angle. MDC estimates suggest that substantial changes in both measures would be required to enable interpretation of true change 90% beyond measurement error. The most informative beta and alpha angle measurements occur outside of the superior plane and vary between individuals, which highlights the need for multi-planar MRIs in the diagnosis of FAI syndrome. Both measures were significantly associated with poorer cartilage health at the chondrolabral junction. Longitudinal prospective investigations are required to establish whether beta angle values can predict subsequent structural deterioration in individuals with FAI syndrome.
dc.languageEnglish
dc.publisherElsevier
dc.relation.ispartofconferencenameOARSI World Congress on Osteoarthritis - Promoting Clinical and Basic Research in Osteoarthritis
dc.relation.ispartofconferencetitleOsteoarthritis and Cartilage
dc.relation.ispartofdatefrom2018-04-26
dc.relation.ispartofdateto2018-04-29
dc.relation.ispartoflocationLiverpool, England
dc.relation.ispartofpagefromS442
dc.relation.ispartofpagetoS442
dc.relation.ispartofissueSupplement 1
dc.relation.ispartofvolume26
dc.subject.fieldofresearchBiomedical engineering
dc.subject.fieldofresearchClinical sciences
dc.subject.fieldofresearchSports science and exercise
dc.subject.fieldofresearchcode4003
dc.subject.fieldofresearchcode3202
dc.subject.fieldofresearchcode4207
dc.subject.keywordsScience & Technology
dc.subject.keywordsLife Sciences & Biomedicine
dc.subject.keywordsOrthopedics
dc.subject.keywordsRheumatology
dc.titleIs beta angle the new alpha angle? Reliability and correlation with cartilage health in femoroacetabular impingement syndrome
dc.typeConference output
dc.type.descriptionE3 - Conferences (Extract Paper)
dcterms.bibliographicCitationDiamond, LE; Murphy, NJ; Eyles, J; Kim, Y-J; Linklater, JM; Spiers, L; Hunter, D, Is beta angle the new alpha angle? Reliability and correlation with cartilage health in femoroacetabular impingement syndrome, Osteoarthritis and Cartilage, 2018, 26, pp. S442-S442
dc.date.updated2021-03-18T01:11:30Z
gro.hasfulltextNo Full Text
gro.griffith.authorDiamond, Laura


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