title: Noninvasive three-dimensional assessment of femoroacetabular impingement.
abstract: A CT-based method ("HipMotion") for the noninvasive three-dimensional assessment of femoroacetabular impingement (FAI) was developed, validated, and applied in a clinical pilot study. The method allows for the anatomically based calculation of hip range of motion (ROM), the exact location of the impingement zone, and the simulation of quantified surgical maneuvers for FAI. The accuracy of HipMotion was 0.7 +/- 3.1 degrees in a plastic bone setup and -5.0 +/- 5.6 degrees in a cadaver setup. Reliability and reproducibility were excellent [intraclass correlation coefficient (ICC) > 0.87] for all measures except external rotation (ICC = 0.48). The normal ROM was determined from a cohort of 150 patients and was compared to 31 consecutive hips with FAI. Patients with FAI had a significantly decreased flexion, internal rotation, and abduction in comparison to normal hips (p < 0.001). Normal hip flexion and internal rotation are generally overestimated in a number of orthopedic textbooks. HipMotion is a useful tool for further assessment of impinging hips and for appropriate planning of the necessary amount of surgical intervention, which represents the basis for future computer-assisted treatment of FAI with less invasive surgical approaches, such as hip arthroscopy.
authors.affiliation: Center for Computer Assisted and Reconstructive Surgery, New England Baptist Hospital, Tufts University, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Moritz
authors.initials: M
authors.lastname: Tannast
authors.forename: Monika
authors.initials: M
authors.lastname: Kubiak-Langer
authors.forename: Frank
authors.initials: F
authors.lastname: Langlotz
authors.forename: Marc
authors.initials: M
authors.lastname: Puls
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Murphy
authors.forename: Klaus A
authors.initials: KA
authors.lastname: Siebenrock
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000473:pathology*; D000328:Adult; D000368:Aged; D003198:Computer Simulation; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000473:pathology*; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed