Femoroacetabular Impingement and Pelvic Incidence: Radiographic Comparison to an Asymptomatic Control

Michael D. Hellman, Bryan D. Haughom, Nicholas Brown, Yale A. Fillingham, Marc J. Philippon, Shane J. Nho

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18 Citations (Scopus)


Purpose To investigate whether pelvic incidence (PI) in patients with symptomatic femoroacetabular impingement was different from that in a normal population. Methods Retrospective analysis of 30 consecutive female and 30 consecutive male patients with computed tomography scans who underwent hip arthroscopy for FAI. PI was measured using scout lateral radiographs. The center-edge angle (CEA), acetabular version, and α angle were also measured. Each patient was subcategorized as having a cam-type deformity (α angle >55°), a deep socket deformity (CEA >39°), and/or a retroverted acetabulum (acetabular anteversion <15°). Our group and subgroups were compared with a historical control group from a previously published study of 300 volunteers. Each group was compared using a Student t test. Results Our mean PI was 49.31° ± 12.34° (range, 28.4°-79.5°), less than the asymptomatic historical control (n = 300) with a mean PI of 55.0° ± 10.6° (range, 33°-82°) (P <.001). The subgroups for cam deformity, deep socket deformity, and acetabular retroversion have a mean PI of 48.89° ± 11.81°, 38.30° ± 7.56°, and 44.93° ± 11.32°, respectively. All had a significantly lower PI than the historical control (P <.001, P <.001, P <.001, respectively). Conclusions We conclude that patients presenting with FAI may have a lower PI than the general population. The clinical significance of a 5.7° difference in PI remains unknown. Level of Evidence Level III, retrospective comparative study.

Original languageEnglish
Pages (from-to)545-550
Number of pages6
JournalArthroscopy - Journal of Arthroscopic and Related Surgery
Issue number3
Publication statusPublished - 1 Mar 2017
Externally publishedYes


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