Ask the Vet: Orthopedic Surgery

Do you have concerns regarding orthopedic surgery on your horse? Pose your questions during the month of October to our AAEP expert, Dr. Chris Bell regarding orthopedic surgery, what to expect before and after.

Question: My horse recently had arthroscopic surgery. He was bleeding into the tibiotarsal joint in his right hock. The surgeon discovered a very large fibrous band of tissue in the joint that had a blood vessel in it. He felt it was so large that he could not resect it without significant risk, and it was too large to use a laser. He had never seen a case like this previously. Have you run across any cases like this? If so, were you able to resect the fibrous band of tissue? Are there other methods available to shrink the band of tissue? Could the bleeding into the hock cause the band of tissue to develop? If you have observed these types of cases, what was the outcome post surgery? I sincerely hope you will respond as this is so rare. I am trying to find any experts who have dealt with cases like this so I can help my horse make a full healthy recovery. Thank you for your time.
Thank you for your question. This does sound like an unusual case. I suspect the large fibrous band could have been due to the previous bleeding into the tibiotarsal joint. As the blood components reabsorb from the joint, they can sometimes leave behind a sticky fiber substance called fibrin. This fibrin will stick together and can form bands or webs. These bands then mature into a fibrous tissue. I have seen this before in different joints and tendon sheaths. Often these bands can be appreciated on ultrasound as well as during arthroscopic surgery. 
In most cases, these fibrous bands can be resected but in this case, it sounds like the surgeon had seen a possible blood vessel within the band. That is very unusual and could limit the ability to resect.
As far as your options to remove the tissue, it will depend on how large the blood supply is to the tissue and where the tissue is located within the joint. It may be more web-like tissue than a distinct band of tissue - difficult to tell you the exact options without seeing this band. Potentially, the surgeon could ultrasound the joint and identify the size of the blood supply in the tissue. If there is no major blood supply then the surgeon will be able to go back into the joint and resect the tissue. If there is blood supply, then the surgeon may be able to apply hemostatic poly-L-lactate clips to the blood vessel and then resect the tissue. Another option for the surgeon would be to perform a arthrotomy (open the joint) and remove the tissue. This type of approach would allow good visualization for the surgeon during surgery if there was bleeding but does carry an increased risk of infection and is not as cosmetic as arthroscopy post-operatively.
 This is a rare case and I wish you and Rex all the best. I am sure your surgeon will be happy to discuss your options from this point forward and I am hopeful that this does not limit his future athletic performance or comfort.
Question: This is follow up on the 2.5 year old Quarter horse with the patella luxation. Radiographs indicated no ligament, tendon, or knee cap damage as the ridges appear to be fine (Dr. Dunlap included the views you recommended). We are trying 6 to 8 weeks of rest in a 24 x 36 paddock, hoping the strain heals and patella will reseat. He is not experiencing any pain or lameness. In your experience, does this type of injury, correct itself? Thank you for your suggestions.
If the ridges appear normal, then the luxation is likely due to trauma and the patella needs to be reseated into the trochlear groove. In order for the patella to luxation, there was stretching of the collateral ligaments of the patella. If the patella is reseated and the horse is rested (as your veterinarian is recommending), then there is a potential that the collateral ligaments and collateral structures, which hold the patella in place, will scar and heal. In some cases, the patella will need to be surgically repaired and the surgeon will perform a procedure to strengthen the torn collateral ligament structures of the patella. 
 It is important that the patella is currently reseated during the rest phase of the recovery otherwise surgical correction will likely be required to keep the patella seated in the correct position. Best of luck!
Question: Is it recommended to do surgery by cutting the flexor ligament in a horse that has an 11 degree rotation of the coffin bone?
Cutting the deep digital flexor tendon (DDFT) is one option to help treat rotation of the coffin bone. The surgery is performed to relieve the tension of the DDFT on the back of the coffin bone and thereby, hopefully, prevent further rotation of the coffin bone within the hoof. There are no hard guidelines for when to cut the DDFT. Some soft guidelines include greater than 15 degrees of rotation, refractory to pain management, presence of the coffin bone through the sole. These are guidelines only. 
There are several other options available to treat rotational laminitis. Depending on the severity and rapidity of the laminitis onset, other options may include, anti-inflammatories, cold therapy, padded frog support shoes, Styrofoam shoes, derotational shoeing treatments, etc. 
You should discuss all the possible options with your veterinarian and farrier before making a final decision. Some horses can return to some form of athletic work after DDFT transection (cutting the flexor tendons) but the decision should be made once all other options have been weighed and considered.
Question: My 2 1/2-year-old Quarter horse gelding, has dislocated his knee cap. My veterinarian said it is from a possible slip/sudden twist that could have caused the problem. He is not lame or experiencing severe pain. The knee cap slips out of position when placed back in position. The course of action is 10cc benamine for five days and stall rest. His training has been ground manners and ponying with a reliable trail horse. He has carried a saddle, but never had weight on his back. Is surgery down the road for him? What are his chances of being more than a pasture ornament? I will keep him as that if that is what will keep him healthy.
Thanks for the interesting question. Luxation (dislocation) of the patella (knee cap) is fairly rare in Quarter Horses. It is seen more commonly in minature horses and ponies. The cause is often related to an anatomical abnormality in the end of the femur bone (part of the stifle joint). It is good that your horse is not in pain and able to move around normally. Once the five day prescribed course of anti-inflammatories is finished, your vet may want to take some radiographs (x-rays) of the stifle joint to confirm that the patella does indeed luxate and the position of the patella once luxated. 
In addition to the standard views of the stifle, your vet should take a skyline or flexed skyline view of the stifle joint/patella. The vet will need to look at the end of the femur bone and see if the trochlear ridges are normal. These ridges help hold the patella in the proper position. In horses with a luxated patella (dislocated knee cap), one or both of these ridges will be malformed or missing. This will be important to know in order to determine if surgery is needed. 
Once the radiographs are taken, your vet may refer your horse to a board certified equine surgeon for a consultation. In some cases, surgery will be required to correct the malformed femur and in other cases a more conservative approach may be available to help stabilize the patella and patellar ligaments.Once you have some more information about exactly what is going on, your vet will be able to give you a better idea of your horse's future athletic prospects. All the best!