Normal values of Wiberg’s lateral center-edge angle and Lequesne’s acetabular index–a coxometric update

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266

Background Both acetabular undercoverage (hip dysplasia) and overcoverage (pincer-type femoroacetabular impingement) can result in hip osteoarthritis. In contrast to undercoverage, there is a lack of information on radiographic reference values for excessive acetabular coverage. Questions/purposes (1) How do common radiographic hip parameters differ in hips with a deficient or an excessive acetabulum in relation to a control group; and (2) what are the reference values determined from these data for acetabular under-and overcoverage? Methods We retrospectively compared 11 radiographic parameters describing the radiographic acetabular anatomy among hip dysplasia (26 hips undergoing periacetabular osteotomy), control hips (21 hips, requiring no rim trimming during surgical hip dislocation), hips with overcoverage (14 hips, requiring rim trimming during surgical hip dislocation), and hips with severe overcoverage (25 hips, defined as having acetabular protrusio). The hips were selected from a patient cohort of a total of 593 hips. Radiographic parameters were assessed with computerized methods on anteroposterior pelvic radiographs and corrected for neutral pelvic orientation with the help of a true lateral radiograph. Results All parameters except the crossover sign differed among the four study groups. From dysplasia through control and overcoverage, the lateral center-edge angle, acetabular arc, and anteroposterior/craniocaudal coverage increased. In contrast, the medial center-edge angle, extrusion/acetabular index, Sharp angle, and prevalence of the posterior wall sign decreased. The following reference values were found: lateral center-edge angle 23°to 33°, medial center-edge angle 35°to 44°, acetabular arc 61°to 65°, extrusion index 17% to 27%, acetabular index 3°to 13°, Sharp angle 38°to 42°, negative crossover sign, positive posterior wall sign, anterior femoral head coverage 15% to 26%, posterior femoral head coverage 36% to 47%, and craniocaudal coverage 70% to 83%.

Section: Discussionmentioning

confidence: 99%

What Are the Radiographic Reference Values for Acetabular Under- and Overcoverage?

Tannast

Hanke

Zheng

et al. 2015

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266

“…Two of us (SM, MA) used Merge 1 PACS TM imaging software (Merge Healthcare Inc, Chicago, IL, USA) to measure the alpha angle [25,35], LCEA [41], and MPFA [1,27] on each femoral rotation radiograph (Fig. 3).…”

Section: Methodsmentioning

confidence: 99%

“…More recently, AP radiographs have been used for assessment of cam morphology [2,11,23]. Additionally, other measurement parameters, such as the lateral center-edge angle (LCEA) [41] and medial proximal femoral angle (MPFA) [27], both originally validated on AP radiographs, have been adapted in diagnosing FAI acetabular morphologic features (pincer type) [5,18,29] and used to predict the progression of OA [1].…”

Section: Introductionmentioning

confidence: 99%

“…Abnormalities of morphologic features that can lead to FAI include cam abnormality on the femoral side and/or pincer overcoverage on the acetabular side [15,33]. Normal parameters for both of these have been defined for plain radiography and advanced imaging [2,5,7,14,19,29,35,37,41]. The alpha angle, Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Does Femoral Rotation Influence Anteroposterior Alpha Angle, Lateral Center-edge Angle, and Medial Proximal Femoral Angle? A Pilot Study

Monazzam

Bomar

Agashe

et al. 2013

Background Femoral rotation on AP radiographs affects several parameters used to assess morphologic features of the proximal femur but its effect on femoroacetabular impingement parameters remains unknown. Question/purposes We therefore evaluated and characterized the potential effect of femoral rotation on (1) AP alpha angle, (2) lateral-center edge angle (LCEA), and (3) medial proximal femoral angle (MPFA) on AP hip radiographs. Methods We took seven AP hip radiographs at intervals of successive femoral rotation on a single dry, cadaveric specimen: 60°, 40°, and 20°internal rotation; 0°neutral/ anatomic rotation; and 20°, 40°, and 50°external rotation. The AP alpha angle, LCEA, and MPFA were measured on all radiographs by two independent evaluators.Results Within the range of femoral rotation studied, the AP alpha angle ranged from 39°to 62°, the LCEA from 25°to 35°, and the MPFA from 70°to 115°. MPFA and AP alpha angle showed a linear relationship with femoral rotation. Each additional degree of internal rotation produced a reciprocal reduction of the MPFA by 0.36°and the AP alpha angle by 0.18°and vice versa in external rotation. The LCEA, especially within the internal rotation range, showed minimal variation. Conclusions These changes in radiographic parameters emphasize the importance of femoral rotation and patient positioning. We recommend radiographs be evaluated for excessive femoral rotation or nonstandardized positioning before interpretation for diagnostic and treatment implications. It may be prudent to repeat radiographs in these circumstances or, when standardized positioning is not feasible, proceed toward advance imaging.

“…The CE angle was assessed ( Fig. 1) according to a previously described technique [54]. A threshold of 39°was used as a sign of impingement [4].…”

Section: Imaging Techniques and Analysesmentioning

confidence: 99%

Femoroacetabular Impingement: Prevalent and Often Asymptomatic in Older Men: The Osteoporotic Fractures in Men Study

Nardo

Parimi

Liu

et al. 2015

Background The epidemiology of femoroacetabular impingement (FAI) is important but incompletely understood, because most reports arise from symptomatic populations. Investigating the prevalence of FAI in a community-based cohort could help us better understand its epidemiology and in particular the degree to which it might or might not be associated with hip pain.Questions/purposes The purposes of this study were (1) to evaluate the proportion of older (C 65 years of age) men with morphologic abnormalities consistent with FAI; and (2) to assess the association of the morphologic abnormalities with prevalent radiographic hip osteoarthritis (OA) and hip pain. Methods Anteroposterior radiographs were obtained in 4140 subjects (mean age ± SD, 77 ± 5 years) from the Osteoporotic Fractures in Men study. We assessed each hip for cam, pincer, and mixed FAI types using validated radiographic definitions. Both intra-and interobserver reproducibility were [ 0.9. Radiographic hip OA was assessed by an expert reader (intraobserver reproducibility, 0.7-0.8) using validated methods, and summary grades of 2 or greater (on a scale from 0 to 4) were used to define radiographic hip OA. Covariates including hip pain in the last 30 days were collected by questionnaires that were answered by all patients included in this report. Logistic regressions with generalized estimating equations were performed to evaluate the association of radiographic features of FAI and arthrosis. Results Pincer, cam, or mixed types of radiographic FAI had a prevalence of 57% (1748 of Conclusions FAI is common in older men and represents more of an anatomic variant rather than a symptomatic disease. This finding should raise questions on how age, activities, and this anatomic variant each contribute to result in symptomatic disease. Level of Evidence Level III, prognostic study.