title: Fourier analysis of vertical ground reaction forces in dogs with unilateral hind limb lameness caused by degenerative disease of the hip joint and in dogs without lameness.
abstract: OBJECTIVE
  To evaluate the applicability of Fourier analysis for assessment of ground reaction forces (GRFs) and differentiation between dogs with unilateral hind limb lameness caused by degenerative joint disease of the hip (DJD-H) and dogs without lameness.
  
  
  METHODS
  37 dogs with or without unilateral DJD-H.
  
  
  METHODS
  Data were obtained from other studies and analyzed retrospectively. Among the 37 dogs, 20 had unilateral DJD-H and 9 (non-Belgian Malinois breeds) had no lameness; another 8 were nonlame Belgian Malinois (radiographically confirmed Fédération Cinologique International classification A [ie, no hip dysplasia or DJD-H]). Gait data acquisition was performed as dogs walked on a treadmill with integrated force platforms. The peak vertical force, mean vertical force, and vertical impulse were compared among the 3 groups. Fourier analysis was performed on the force-time curves for the vertical GRF, and calculated Fourier coefficients were compared within and between groups.
  
  
  RESULTS
  Lameness in the hind limbs with DJD-H was detectable via conventional analysis of the GRF as well as via Fourier analysis. However, subtle gait aberrations in the forelimbs of the dogs with DJD-H were detected solely via Fourier analysis of GRFs and remained undetected via conventional analysis.
  
  
  CONCLUSIONS
  Results support the applicability of Fourier analysis for evaluation of force-time curves of GRFs. Fourier analysis can reveal subtle alterations of gait that might otherwise remain inapparent; however, further investigation is necessary before this method can be routinely applied for lameness detection in dogs.
authors.affiliation: Clinic for Small Animal Surgery and Ophthalmology, Clinical Department of Small Animals and Horses, University of Veterinary Medicine, Veterinaerplatz 1, A-1210 Vienna, Austria.
authors.forename: Nikola
authors.initials: N
authors.lastname: Katic
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Bockstahler
authors.forename: Marion
authors.initials: M
authors.lastname: Mueller
authors.forename: Christian
authors.initials: C
authors.lastname: Peham
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000503:physiopathology*; D004285:Dogs; D005583:Fourier Analysis; D006621:Hip Joint / Q000503:physiopathology*; D007592:Joint Diseases / Q000503:physiopathology / Q000662:veterinary*; D007794:Lameness, Animal / Q000503:physiopathology*; D012189:Retrospective Studies