A nail or spike in the bottom of the foot can be very serious and warrants emergency attention and referral. Prognosis is often guarded, even after treatment.
A recent review published in the Equine Veterinary Journal involved 95 such cases from 4 UK equine hospitals. Each had suffered a puncture wound that went deeper than just the sole or frog, penetrating structures such as the navicular bursa, tendon sheath or coffin joint.
In many cases more than one structure was damaged — so the nail might have gone through the tendon sheath, the tendon and into the joint.
Each horse was treated intensively with keyhole surgery and every possible technique to prevent infection and restore full function.
Despite such efforts, the rate of return to full soundness where the bursa, tendon sheath or joint had been penetrated was only 36%. In fact, only 56% of cases survived and a significant proportion of these were permanently lame.
If the nail or spike had penetrated the central sulcus, or cleft, of the frog, the prognosis for survival and recovery was lower than if it had penetrated the lateral sulci. This is probably because less pressure is exerted here during weight bearing.
Ponies, cobs and draught horses appeared to have a slightly better outlook for return to work than warmbloods, thoroughbreds and Arabs. A likely reason for this is that they are generally expected to do less and a low level of lameness might be better tolerated.
Whatever the age or breed, the time between the discovery of the nail and referral to hospital was shown to affect outcome — emphasising the need for immediate action in such cases.