The acetabular wall index for assessing anteroposterior femoral head coverage in symptomatic patients. Clin Orthop Relat Res 2012 Dec;470(12):3355-60
Date
07/17/2012Pubmed ID
22798137Pubmed Central ID
PMC3492620DOI
10.1007/s11999-012-2477-2Scopus ID
2-s2.0-84871614877 (requires institutional sign-in at Scopus site) 94 CitationsAbstract
BACKGROUND: Understanding acetabular pathomorphology is necessary to correctly treat patients with hip complaints. Existing radiographic parameters classify acetabular coverage as deficient, normal, or excessive but fail to quantify contributions of anterior and posterior wall coverage. A simple, reproducible, and valid measurement of anterior and posterior wall coverage in patients with hip pain would be a clinically useful tool.
QUESTIONS/PURPOSES: We (1) introduce the anterior wall index (AWI) and posterior wall index (PWI), (2) report the intra- and interobserver reliability of these measurements, and (3) validate these measurements against an established computer model.
METHODS: We retrospectively reviewed 87 hips (63 patients) with symptomatic hip disease. A validated computer model was used to determine total anterior and posterior acetabular coverage (TAC and TPC) on an AP pelvis radiograph. Two independent observers measured the AWI and PWI on each film, and the intraclass correlation coefficient (ICC) was calculated. Pearson correlation was used to determine the strength of linear dependence between our measurements and the computer model.
RESULTS: Intra- and interobserver ICCs were 0.94 and 0.99 for the AWI and 0.81 and 0.97 for the PWI. For validation against the computer model, Pearson r values were 0.837 (AWI versus TAC) and 0.895 (PWI versus TPC). Mean AWI and PWI were 0.28 and 0.81 for dysplastic hips, 0.41 and 0.91 for normal hips, 0.61 and 1.15 for hips with a deep acetabulum.
CONCLUSIONS: Our data suggest these measures will be helpful in evaluating anterior and posterior coverage before and after surgery but need to be evaluated in asymptomatic individuals without hip abnormalities to establish normal ranges.
LEVEL OF EVIDENCE: Level III, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.
Author List
Siebenrock KA, Kistler L, Schwab JM, Büchler L, Tannast MMESH terms used to index this publication - Major topics in bold
AcetabulumAdolescent
Adult
Aged
Computer Simulation
Female
Femur Head
Hip Joint
Humans
Joint Diseases
Linear Models
Male
Middle Aged
Observer Variation
Predictive Value of Tests
Prognosis
Radiography
Reproducibility of Results
Retrospective Studies
Severity of Illness Index
Young Adult