BACKGROUND: Cam-type femoroacetabular impingement is secondary to lack of concavity at the anterosuperior femoral head-neck junction, resulting in reduced femoral head-neck offset and femoral head asphericity. This morphologic deformity can be detected by MRI and plain radiographs and quantified using the alpha angle. QUESTIONS/PURPOSES: We evaluated the accuracy and reproducibility of plain radiography in the diagnosis of cam-type deformity. METHODS: Sixty-eight patients (37 females, 31 males) with a mean age of 38 years (range, 17-60 years) were treated for intraarticular hip pathology with 43 hips having cam-type femoroacetabular impingement and 25 having isolated labral tears. All patients had alpha angle measurements made on plain radiographs (AP pelvis, crosstable lateral, Dunn view) and multiplanar MRI using an alpha angle of more than 50.5° as the gold standard. RESULTS: The Dunn view had a sensitivity of 91%, specificity of 88%, positive predictive value of 93%, negative predictive value of 84%, and accuracy of 90% for diagnosing the cam deformity associated with femoroacetabular impingement. The Pearson correlation coefficients between the MRI and plain radiography values were 0.702, 0.552, and 0.349 for the Dunn, crosstable lateral, and AP views, respectively. CONCLUSIONS: Our observations validate the clinical use of the Dunn view in the evaluation of the femoral head-neck contour in cam-type femoroacetabular impingement. LEVEL OF EVIDENCE: Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
BACKGROUND: Cam-type femoroacetabular impingement is secondary to lack of concavity at the anterosuperior femoral head-neck junction, resulting in reduced femoral head-neck offset and femoral head asphericity. This morphologic deformity can be detected by MRI and plain radiographs and quantified using the alpha angle. QUESTIONS/PURPOSES: We evaluated the accuracy and reproducibility of plain radiography in the diagnosis of cam-type deformity. METHODS: Sixty-eight patients (37 females, 31 males) with a mean age of 38 years (range, 17-60 years) were treated for intraarticular hip pathology with 43 hips having cam-type femoroacetabular impingement and 25 having isolated labral tears. All patients had alpha angle measurements made on plain radiographs (AP pelvis, crosstable lateral, Dunn view) and multiplanar MRI using an alpha angle of more than 50.5° as the gold standard. RESULTS: The Dunn view had a sensitivity of 91%, specificity of 88%, positive predictive value of 93%, negative predictive value of 84%, and accuracy of 90% for diagnosing the cam deformity associated with femoroacetabular impingement. The Pearson correlation coefficients between the MRI and plain radiography values were 0.702, 0.552, and 0.349 for the Dunn, crosstable lateral, and AP views, respectively. CONCLUSIONS: Our observations validate the clinical use of the Dunn view in the evaluation of the femoral head-neck contour in cam-type femoroacetabular impingement. LEVEL OF EVIDENCE: Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
Authors: Reinhold Ganz; Javad Parvizi; Martin Beck; Michael Leunig; Hubert Nötzli; Klaus A Siebenrock Journal: Clin Orthop Relat Res Date: 2003-12 Impact factor: 4.176
Authors: Milad Masjedi; Charles S Marquardt; Isabella M H Drummond; Simon J Harris; Justin P Cobb Journal: Skeletal Radiol Date: 2012-06-08 Impact factor: 2.199
Authors: C Ratzlaff; C Zhang; J Korzan; L Josey; H Wong; J Cibere; H M Prlic; J A Kopec; J M Esdaile; L C Li; M Barber; B B Forster Journal: Rheumatol Int Date: 2015-10-03 Impact factor: 2.631
Authors: Alberto Aliprandi; Francesco Di Pietto; Paolo Minafra; Marcello Zappia; Simona Pozza; Luca Maria Sconfienza Journal: Radiol Med Date: 2013-11-26 Impact factor: 3.469
Authors: Matthias Lahner; Nadine-Lucie Jahnke; Sonja Zirke; Wolfram Teske; Gregor Vetter; Christoph von Schulze Pellengahr; Kiriakos Daniilidis; Marco Hagen; Lars Victor von Engelhardt Journal: Int Orthop Date: 2013-09-14 Impact factor: 3.075
Authors: Vasco V Mascarenhas; Paulo Rego; Pedro Dantas; Augusto Gaspar; Francisco Soldado; José G Consciência Journal: Eur Radiol Date: 2016-08-30 Impact factor: 5.315