Outcomes After Surgical Correction of Flexural Deformities in Foals

Flexural deformities of the coffin joint are common in foals and may be present at birth or acquired in older foals or weanlings. There is a characteristic upright hoof conformation where the angle of the dorsal hoof wall is greater than 60 degrees to the ground. When foals go upright, the heel may be lifted off the ground or grow long, creating a club foot. This flexural deformity results from a deformity of the deep digital flexor musculotendinous unit.

Many cases respond to conservative or medical management. A few days of confinement for the mare and newborn foal will often lead to normal conformation. High doses of oxytetracyclines are also used in newborn and older foals. Leg wraps or splints may be used in more protracted cases. In older foals, confinement, pain relief, heel trimming and wedges, and growth checks are used in conservative management.

However, some horses do not respond to these management techniques. These cases may require surgery to sever the accessory ligament of the deep digital flexor tendon below the knee. This measure is combined with heel trimming at surgery and weekly after that until a normal heel length and hoof angle are achieved.

Australian researchers reviewed the racing records of 46 young Thoroughbred horses that had undergone surgical correction compared to 92 maternal siblings. Each case was compared to 2 maternal siblings. Surgery was performed at an average age of 5 months but ranged from 2 days to 563 days. Horses undergoing surgery were less likely to race (48% versus 77%), but if they did race, they performed just as well as their siblings. Time to first race, number of starts, and prize money were not different between treated horses and controls. Age at surgery did not influence the likelihood of starting in a race in this study. Other researchers have found that older surgical cases had less favourable outcomes. When horses are older than six months at the time of surgery, the club foot is less likely to resolve, but this study shows that an athletic career is still feasible.

This study suggests that aggressive conservative management of foals with flexural deformities is important to resolve the problem before it becomes chronic, but that surgical correction is worth considering for those that don’t respond, even in weanlings and yearlings.

Reference: Australian Veterinary Journal 2011 89 (7):265.