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Case Reports
. 2023 May;9(3):1143-1148.
doi: 10.1002/vms3.1083. Epub 2023 Feb 3.

Bilateral patellar aplasia in a foal

Elsa K Ludwig  1 , Kim Hallowell  1 , Mandy Womble  2 , Erin O'Neil  1
Affiliations
Case Reports

Bilateral patellar aplasia in a foal

Elsa K Ludwig et al. Vet Med Sci. 2023 May.

Abstract

A 2-day-old Cleveland Bay colt was referred to the Equine Emergency Service of the Farm Animal and Equine Veterinary Medical Center at North Carolina State University's College of Veterinary Medicine for evaluation of decreased nursing behaviour and right hindlimb lameness of 2 days' duration. When assisted to stand, the foal was unable to extend either hindlimb or bear weight on the hindlimbs, the right patella was luxated laterally and unable to be reduced, and the foal assumed a crouched position. Stifle radiographs revealed minimal, heterogeneous, ill-defined ossification of both patellae. Due to the severity of the musculoskeletal defects, humane euthanasia was elected. Post-mortem examination identified a congenital malformation of both patella bones with failure of ossification and cardiac changes suggestive of right atrioventricular valve dysplasia. Histology of the patellae showed no evidence of osteoid deposition or ossification. To our knowledge, bilateral congenital patellar aplasia has not been previously described in foals.

Keywords: aplasia; congenital; foal; horse; patella.

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Conflict of interest statement

No conflicts of interest have been declared.

Figures

FIGURE 1
FIGURE 1
Crouched posture of a 2‐day‐old Cleveland Bay colt affected with bilateral patellar aplasia. Still image obtained from video.
FIGURE 2
FIGURE 2
(a) Lateromedial and (b) craniodistal‐cranioproximal (skyline) radiographs of the left and right stifles depicting minimal, heterogeneous, ill‐defined ossification of both patellae (white arrows).
FIGURE 3
FIGURE 3
Bilateral lateromedial (a) carpus and (b) hock radiographs showing moderate rounding of the cuboidal bones and increased joint space for both carpi and tarsi.
FIGURE 4
FIGURE 4
Post‐mortem photograph of the right femorotibial joint containing a free‐floating, dark red to yellow fibrinous clot (white arrow).
FIGURE 5
FIGURE 5
(a) Post‐mortem gross cross‐sectional photograph of the right patella. Ossification is not grossly present; the patella is primarily cartilaginous. (b) Histology of the right patella shows no evidence of osteoid deposition or ossification. Haematoxylin‐eosin staining at 20× (inset, 40×).
FIGURE 6
FIGURE 6
Post‐mortem photograph of the moderately dilated right atrium and the mildly thickened atrioventricular valve leaflets (white arrows).
See this image and copyright information in PMC

References

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