Horseman's News 2007

Question: My 14-month-old stud colt has bench knee. Can thisbe corrected?

Answer: Bench knees is a conformational flaw in which the knees are offset to the outside of the limb. It occurs in the forelimbs and is noticeable when viewed from the front. What you see is that the cannon bone is not straight with the upper forelimb and is positioned lateral or outside of the upper limb. The limb can still appear to be straight but simply offset. Often times, pigeon toe or toe in conformation accompanies this conformational flaw.

This is a conformational defect and it cannot be corrected surgically. These horses are more likely to develop splints on the medial (inside) splint bone as the concussion and load is increased. The inside of the limb always carries more of the load, but just more so if the horse is bench kneed. If this is a Quarter horse then you might watch for pigeon toed or toe in conformation as the horse ages. At 14 months you may notice this now but by 18 to 24 months it should be obvious if it is going to develop.

Conformational flaws have been a lively topic of discussion this month. Some can be corrected and some cannot. This is why care and consideration should be taken into your breeding program. I am sure you thought long and hard about what stallion would service your mare. You might have 10 other foals by the same sire that are all perfect. If you know the sire, and he has produced many foals, contact the owner and find out if this conformational flaw is a problem. If it comes from the mare, it is more difficult. She may have 10 to 12 foals in her breeding career while the stallion can have 3 to 4 times that many in one year.

In short, nothing you can do. Enjoy the horse but be ready do deal with medial (inside) splints and other common ailments on the inside of the leg. The horse should be fine. There are worse conformational flaws you could deal with.

Question: What are the pros and cons of nerving a horse? My horse has navicular problems in one front foot and also suffered a small tear in his deep digital flexor tendon under his coffin bone in 2007. After a recent MRI, the tendon shows no activity and seems to have healed well. But, even after two separate doses of Tildren, one in 2006 and another last month, my gelding is still intermittently lame. Is nerving a possibility for him? He is 14-years-old (this month) and I show him at Prix St.George.

Answer: Sounds like this horse has been thoroughly worked up and Tildren therapy has been equivocal. I don’t know if you know how Tildren works. It is a biphosphonate. This class of drug is primarily used for osteoporosis in humans and is approved in Europe in horses for treatment of navicular disease. The goal is to reduce enlargement of the invaginations in the navicular bone by reducing osteoclastic activity. Osteoclasts are cells within bone that cause breakdown of bone. Hence the popularity in human medicine. One treatment you did not mention is coffin joint injection or navicular bursa injection. With the deep flexor tear, using IRAP therapy in the navicular bursa is also an option.

Now to your question regarding neurectomy. If the horse goes sound with a foot block (anesthesia of the palmar digital nerves) then neurectomy is an option. Secondly, there must not be excessive radiographic or MRI change to the flexor surface of the navicular bone. This may be very important in your horse as it has sustained a deep flexor tear. What happens if there is excessive change is that the bone will literally tear through the deep flexor and, if totally severed, could require euthanasia. We typically use neurectomy after all other treatments fail. If this is the case with your horse and it meets the above criteria, then neurectomy is an option. The surgery requires general anesthesia and 3 to 4 weeks recovery time. There are many different surgical techniques and your surgeon can advise you of these. Basically, he or she will use the technique they are comfortable with. The surgery does not cure the condition. It simply permanently alleviates pain in the foot. It is advised to continue to shoe the horse with heel elevation and shorten the breakover to ease stress on the deep flexor tendon.

I perform many of these and have had very good success. It is reasonable to expect 2 to 4 years of performace after surgery. Remember, the above criteria should be met to ensure safety and success.

Neurectomy gets a bad rap sometimes. I see many horses go on and do well after the procedure. I would encourage you to pursue the surgery if all other treatments have failed and it meets the criteria above. I think you will be surprised as to how well the horse does. On the other side, it is difficult to sell a “nerved” horse. Be prepared to be the last owner or if selling, the horse will sell on its merits in the show ring.

Question: Is orthopedic surgery an option with ringbone? If so, what are the risks? What procedure would be used? What is the success rate?

Answer: There is a surgical option for ringbone. Whether to operate depends on the degree of radiographic changes and lameness. If recently diagnosed, and radiographic changes are minimal, you might try injecting the pastern joint with corticosteroids +/- hyaluronic acid.

Surgical treatment has a very good success rate. Surgery is done to arthrodese (fuse) the pastern joint. Basically, you fuse the long pastern bone to the short pastern bone and essentially make it one bone. We use surgery on horses that have significant radiographic change and are not responsive to joint injection.

The procedure is placing bone screws or bone plates and screws across the joint after removing the cartilage in the joint. Some surgeons prefer to also add a bone graft in the joint at the time of surgery. The horse is then placed in a cast for 3 to 6 weeks and stall confined. After cast removal, radiographs are taken to assess healing and fusion. Typically, the horse is allowed paddock turn-out for an additional 60 days and then light exercise can begin. Full training and competition can usually resume 6 to 12 months after surgery depending on the horses discipline.

The risks of surgery are typical of all surgery. Anesthetic complications, infection of the bone implants and cast sores are the most common concerns. With the implants we have today and the casting material, complications are not common. The concern most owners face is the cost of surgery and the down time before you can continue training and showing. The good news is, if you invest in the surgery and be patient, these horses typically can go back to work.

Reprinted with the permission of the AAEP. For more information visit www.AAEP.org