The Crossover Sign Overestimates Acetabular Retroversion
Purchase on Springer.com
$39.95 / €34.95 / £29.95*
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.
The crossover sign is a radiographic finding associated with cranial acetabular retroversion and has been associated with pincer-type femoroacetabular impingement (FAI) in patients with hip pain. Variable morphology, location, and size of the anterior inferior iliac spine (AIIS) may contribute to the crossover sign even in the absence of retroversion. Thus, the sign may overestimate the incidence of acetabular retroversion.
We asked: Can the crossover sign appear on standardized, well-positioned AP pelvis radiographs despite the absence of acetabular retroversion? And what is the contribution of variable size and morphology of the AIIS to a crossover sign?
We evaluated radiographs of 53 patients with symptomatic FAI in the absence of substantial chondral degenerative changes (< Tönnis Grade 2). Forty-one radiographs met the appropriate criteria of neutral tilt and obliquity. Three independent reviewers determined presence and location of the crossover sign. Acetabular version was defined using high-resolution three-dimensional CT. CT reconstructions were used to define three AIIS types addressing AIIS morphology.
Nineteen of 38 radiographs with a crossover sign on AP radiographs had focal or global acetabular retroversion on three-dimensional CT (positive and negative predictive values = 50%). In contrast, the AIIS extended to or below the level of the anterior superior acetabular rim and was partially or completely responsible for the appearance of a radiographic crossover sign in all 19 hips with an anteverted acetabulum. High interobserver reliability (kappa > 0.8) was found for AIIS types.
A crossover sign is frequently present on well-positioned AP pelvis radiographs in the absence of acetabular retroversion. Variable AIIS morphology may explain the appearance of this sign in the presence or absence of acetabular retroversion.
Level of Evidence
Level III, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.
- Beaule PE, Allen DJ, Clohisy JC, Schoenecker PL, Leunig M. The young adult with hip impingement: deciding on the optimal intervention. Instr Course Lect. 2009;58:213–222.
- Dandachli W, Islam SU, Liu M, Richards R, Hall-Craggs M, Witt J. Three-dimensional CT analysis to determine acetabular retroversion and the implications for the management of femoro-acetabular impingement. J Bone Joint Surg Br. 2009;91:1031–1036.
- Dandachli W, Ul Islam S, Tippett R, Hall-Craggs MA, Witt JD. Analysis of acetabular version in the native hip: comparison between 2D axial CT and 3D CT measurements. Skeletal Radiol. 2011;40:877–883. CrossRef
- Dora C, Leunig M, Beck M, Simovitch R, Ganz R. Acetabular dome retroversion: radiological appearance, incidence and relevance. Hip Int. 2006;16:215–222.
- Eckman K, Hafez MA, Ed F, Jaramaz B, Levison TJ, Digioia AM 3rd. Accuracy of pelvic flexion measurements from lateral radiographs. Clin Orthop Relat Res. 2006;451:154–160. CrossRef
- Ferguson SJ, Bryant JT, Ganz R, Ito K. An in vitro investigation of the acetabular labral seal in hip joint mechanics. J Biomech. 2003;36:171–178. CrossRef
- Ganz R, Parvizi J, Beck M, Leunig M, Notzli H, Siebenrock KA. Femoroacetabular impingement: a cause for osteoarthritis of the hip. Clin Orthop Relat Res. 2003;417:112–120.
- Jamali AA, Mladenov K, Meyer DC, Martinez A, Beck M, Ganz R, Leunig M. Anteroposterior pelvic radiographs to assess acetabular retroversion: high validity of the “cross-over-sign.” J Orthop Res. 2007;25:758–765. CrossRef
- Kakaty DK, Fischer AF, Hosalkar HS, Siebenrock KA, Tannast M. The ischial spine sign: does pelvic tilt and rotation matter? Clin Orthop Relat Res. 2010;468:769–774. CrossRef
- Kalberer F, Sierra RJ, Madan SS, Ganz R, Leunig M. Ischial spine projection into the pelvis: a new sign for acetabular retroversion. Clin Orthop Relat Res. 2008;466:677–683. CrossRef
- Larson CM, Kelly BT, Stone RM. Making a case for anterior inferior iliac spine/subspine hip impingement: three representative case reports and proposed concept. Arthroscopy. 2011;27:1732–1737. CrossRef
- Pan HL, Kawanabe K, Akiyama H, Goto K, Onishi E, Nakamura T. Operative treatment of hip impingement caused by hypertrophy of the anterior inferior iliac spine. J Bone Joint Surg Br. 2008;90:677–679. CrossRef
- Siebenrock KA, Kalbermatten DF, Ganz R. Effect of pelvic tilt on acetabular retroversion: a study of pelves from cadavers. Clin Orthop Relat Res. 2003;407:241–248. CrossRef
- Tannast M, Kubiak-Langer M, Langlotz F, Puls M, Murphy SB, Siebenrock KA. Noninvasive three-dimensional assessment of femoroacetabular impingement. J Orthop Res. 2007;25:122–131. CrossRef
- Tannast M, Siebenrock KA, Anderson SE. Femoroacetabular impingement: radiographic diagnosis—what the radiologist should know. AJR Am J Roentgenol. 2007;188:1540–1552. CrossRef
- Tönnis D. [Letter: Congenital hip dysplasia: clinical and radiological diagnosis (author’s transl)] [in German]. Z Orthop Ihre Grenzgeb. 1976;114:98–99.
- The Crossover Sign Overestimates Acetabular Retroversion
Clinical Orthopaedics and Related Research®
Volume 471, Issue 8 , pp 2463-2470
- Cover Date
- Print ISSN
- Online ISSN
- Springer US
- Additional Links
- Industry Sectors
- Author Affiliations
- 1. Department of Orthopedic Surgery, William Beaumont Hospital, Royal Oak, MI, USA
- 2. Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
- 3. MedSport, Sports Medicine and Shoulder Surgery, University of Michigan, 24 Frank Lloyd Wright Drive, Lobby A, Ann Arbor, MI, 48106, USA