Unusual polydactylism in a foal. A case report.

This research reports on a unique case of a two-month-old quarter horse colt which exhibited multiple bone anomalies in its left forelimb. Such anomalies were primarily dealt with surgically, and despite some persisting anatomical oddities, the foal was notably healthier and free from symptoms post-surgery.

Case Description and Findings

• The researchers studied an unusual case of a two-month-old quarter horse colt which was observed to have various skeletal irregularities in its left forelimb. These irregularities consisted of two additional metacarpal bones and carpal bones each, abnormal development of the carpal bone, and a valgus deformity, which is an outward angulation of the bone, stemming from the carpal joint.

Surgical Intervention

• The surgical procedures carried out primarily included the removal of the additional skeletal elements. The largest additional metacarpal bone was taken out in its entirety, and a portion of the smaller one was also removed.
• Following this, the horse’s leg was fitted into a tube cast. This phase of the treatment aimed at managing the deformity and preventing any further injuries to the limb.

Post-surgery Findings

• Post-surgery, the horse exhibited a significant clinical improvement. Although the width of the carpal joint remained larger than normal, the valgus deformity showed a partial response to a surgical procedure known as hemicircumferential periosteal transection, a method treating bone deformities.
• The horse was deemed to be in sound health two and a half years after the surgery, implying the success of the treatment despite the persistent enlargement of the carpal joint.

Conclusions

• This case presents an uncommon occurrence of polydactylism, a condition of having more digits than usual, in a foal. It underscores the potential of surgical intervention for such cases, in improving both the aesthetic aspect and functional health of the affected limb, as evidenced by the fact that no further pain or health issues were reported in the horse over two and a half years after the surgery.