Objective
To determine outcome for foals with incomplete ossification of the tarsal bones and to determine whether clinical and radiographic abnormalities at the time of initial examination were associated with outcome.
Design
Retrospective study.
Animals
22 foals.
Procedure
Information on signalment, history, owner’s initial complaint, clinical findings, whether tarsus valgus was evident, and radiographic abnormalities was obtained from medical records. Radiographic lesions were classified as type I (ie, incomplete ossification with < 30% collapse of the affected bones) or type II (incomplete ossification with > 30% collapse and pinching or fragmentation of the affected bones). Follow-up information was obtained via telephone conversations with owners.
Results
Foals were between 1 day and 10 months old when first examined. Eleven were premature (ie, < 320 days of gestation) or were twins. Sixteen had tarsus valgus. Severity of radiographic lesions was associated with outcome; 4 of 6 foals with type-I incomplete ossification of the tarsal bones performed as intended, but only 3 of 16 foals with type-II incomplete ossification of the tarsal bones performed as intended.
Clinical Implications
For foals with incomplete ossification of the tarsal bones, severity of the radiographic lesions was associated with outcome. Foals with type-II incomplete ossification of the tarsal bones have a guarded prognosis for athletic soundness. (J Am Vet Med Assoc 1998;213:1590–1594)
