Skeletal Manifestations of Heritable Disproportionate Dwarfism in Cats as Determined by Radiography and Magnetic Resonance Imaging

Abstract

Objective The aim of this study was to characterize the radiographic alignment of thoracic and pelvic limbs and evaluate for intervertebral disc disease in cats with feline disproportionate dwarfism (FDD).

Study Design Observational cross-sectional study. Radiographic joint orientation angles were measured in 10 thoracic and pelvic limbs from 5 FDD cats and compared with those angles measured in 24 thoracic limbs and 100 pelvic limbs from skeletally normal cats. Magnetic resonance imaging of the spine was performed in 2 FDD cats for the evaluation of pathology of the intervertebral discs or vertebrae.

Results All limbs from FDD cats possessed deformities. FDD humeri demonstrated procurvatum proximally, and recurvatum distally in the sagittal plane, but showed no difference in the frontal plane. FDD radii possessed excessive recurvatum proximally, and procurvatum distally in the sagittal plane, and varus proximally and valgus distally in the frontal plane. Whereas no torsion was discernible in the humeri, all radii had external torsion. In the frontal plane, FDD femurs exhibited varus both proximally and distally whereas the tibia possessed proximal valgus and distal varus. No torsion in the pelvic limbs was observed. No spinal pathology was detected in the FDD cats included in the original study.

Conclusion Feline disproportionate dwarfism results in significant appendicular deformity in all limbs. The incidence of intervertebral disc degeneration in FDD cats is inconclusive.

Keywords

chondrodysplasia - Munchkin cat - disproportionate dwarfism - joint orientation angles - angular limb deformities

Authors' Contributions

L.M.A., D.B.F., and J.R.C. contributed to conception of study, study design, acquisition of data, data analysis and interpretation and manuscript preparation. K.L.C. contributed to conception of study and acquisition of data. B.T.T. contributed to statistical analysis and manuscript preparation. L.A.L. contributed to concept of study, study design, acquisition of data and manuscript preparation. All authors drafted, revised, and approved the submitted manuscript.

Publication History

Received: 24 August 2020

Accepted: 03 April 2021

Article published online:
03 June 2021

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