|The Facts Around Broken Legs – Part III|
Potential Complications with surgical repair of fractures
Post-fracture complications impacting a horse’s chance of survival can happen preoperatively during transport of the horse to the hospital, intra-operatively (during surgery) and post-surgery during recovery and healing.
Infection is the most important complication of orthopedic surgery in horses. Infection rates vary depending on the type of surgery (open surgery vs. closed techniques), degree of comminution (fragmentation) and surrounding soft tissue damage. Infections are generally treated by delivering large amounts of antibiotics directly to the site of infection, and ironically, this procedure in itself can result in further infection, because the wound is not sealed.
Support limb laminitis is the development of laminitis in the forelimb or hind limb opposite to the injury. Horses constantly move their feet which promotes blood flow to the foot for the delivery of oxygen and nutrients, and removal of waste products. Studies have shown that horses shift weight from one forefoot to the other between 70 and 180 times per hour. Thus, horses unable to shift weight, such as fracture patients, are incapable of achieving this “circulation” in the foot. As a result, tissue fatigue, damage, and necrosis are thought to occur.
It is currently hypothesized that support limb laminitis is related to altered biomechanics and blood flow in the limb bearing more weight. These factors contribute to the separation of the sensitive and insensitive laminae of the foot. This condition is very painful – it would be like your fingernails being pulled off.
The temperament of the horse plays a large part in healing and recovery. Some horses can be difficult when it comes to handling an injured limb and bandaging and treatment can be made difficult and inhibit his recovery. While most horses will allow it, a few won’t and it doesn’t stand them in good stead for a healthy prognosis.
The length of time a horse stays in a hospital will depend on the type of fracture and owner’s ability and competency when it comes to dealing with horses. Owners have to be prepared to check the horse, and his bandages and splints daily and be competent enough to do this. Bandaging a horse too tightly or loosely can do damage either way by blocking off circulation, or allowing too much swelling in the leg to occur. The horse will need to have his temperature taken regularly to determine if he is developing an infection or not.
Box/stable rest is generally prescribed once a horse leaves hospital, although this often doesn’t provide enough immobilization; a horse can still walk around his stable and re-injure himself. When the horse walks there is going to be microscopic movement of the bone/s which can inhibit the healing process.
Methods of Repair in Surgery
Internal fixation is a combination of screws and plates inserted in and around the damaged bone. These techniques allow horses to bear full weight after surgery.
In America work is continuing on developing an external fixation device for horses, much like seen in humans. With horses, the external fixation device acts as a total support so the horses can stand and walk immediately after it is applied, with the pins placed in the bone above the fractured bone, which is the cannon bone, and the device goes all the way down and is glued onto the bottom of the hoof with a metal plate. This bypasses the fracture and the horse is mobile while the fracture heals, and is non- weight bearing.
Recovery from Surgery
Horses being herbivores, it is their instinct to fight or flight. Often before the horse is properly awake, he will be trying to get up and run away from what he thinks is hurting him.
Recovery from anesthetic is one of the horse’s biggest downfalls, with the horse himself being his own worst enemy. Horses wake up struggling and thrashing, which is why the hospitals usually have deep padded rubber walls and floors for the horses to recover and wake up in, and it is the most dangerous time for re-injury of a fracture. The horse will thrash around the padded boxes, and if he hits the sides of the box he can injure himself and break what vets have just spent hours repairing, and immediately he halves his chances of survival.
Ruffian, a champion mare in 1975 in the United States, eventually had to be put down after doing just this, and it was described that she “began throwing her attendants around like toys”, she managed to throw her orthopaedic shoe and cast that had been fitted, and broke her healthy elbow in the process.
The New Bolton Centre in America has developed a unique way to avoid fracture re-injuries due to anesthesia emergence.
They have built a recovery swimming pool where the horse is picked up by a sling, goes along a mono-rail, and is set onto a giant raft. They encase the horse’s limbs in long plastic sleeves that hang into the water. The horse wakes and recovers in the swimming pool, and as soon as he has his complete wits about him, he’s lifted out of the pool with a sling and set on his feet in his stable. When horses wake up in the pool, they might struggle, but nothing will damage them or put their leg in danger. They are already right side up with their legs underneath them, so they tend to feel more relaxed when they come out of anaesthetic.
In the old days, horses were put in slings but it chafed their skin, caused their muscles to atrophy and hindered circulation, with increased swelling to the injury as the horse had no movement.
As we can see, there are no cut and dried solutions, each case is individual and all the facts need to be analyzed before a decision can be made, as each injury is different.