Ever since JB’s accident, I tend to read anything I can get my hands on about tendon, ligament and other orthopedic related injuries, surgeries or treatments. The opening paragraph of a recent article I ran across caught my attention.The article touches on some of the high level issues surrounding tendon and ligament injuries and the subsequent recovery. I have added some information to the points made in this article based on my own personal experience with Pastern Arthrodesis. It includes things I have learned and some of what can be expected when you put a horse through something like this. Hopefully, it may help provide some answers to someone else out there who is facing this surgery with their beloved horse. When I was hunting for more information , it was hard to come by.
Warning- This post got more lengthy than I had hoped.
The article is by:
Jennifer G. Barrett, DVM, PhD, Dipl. ACVS; Marion duPont Scott Equine Medical Center; Virginia-Maryland Regional College of Veterinary Medicine
Tendon and Ligament injuries in horses causes both economic and personal hardship for horse owners and industry professionals. A prolonged period of layup and rehabilitation is necessary, but whether the horse will be sound at the end of the rehabilitation period is uncertain. Lameness due to tendon and ligament injury is common in performance horses, affecting up to 25% of racehorses over a career and accounting for up to 43% of injuries in event horses, but it is also common to companion horses. Chronic lameness often follows the initial injury, with recurrence as high as 80% of racehorses with tendinitis.
Indeed, hardships .. hardships for me, ,my family (believe it or not), for JB and to some extent the vet and his staff( since I bugged them all the time with questions). In JB’s case, there was nothing I could have done to prevent him from rupturing his MCL, other than not letting him be pastured in the adjacent pen next to Grace, who, in hindsight probably antagonized him to the point he couldn’t take it, but the fact remains, it didn’t make the situation any less difficult. From the time of the injury to the point in the road when you get the conformation that everything is healed, the horse owner, the horse, and even to some extent the vet, are on pins and needles. Infection, too much inflammation, broken hardware, lack of healing, potential movement of hardware, or just re-injury . All of these things which could make or break the positive outcome. It could happen in the very beginning, it could happen towards the end, you just don’t know. In the beginning when JB had his cast on, he laid down a lot, (stress a lot) It wasn’t necessarily a bad thing because as long as he was down, the weight was off the leg. This was good in the initial days. But with laying down a lot , you can also have other complications; Gut motility, respiratory issues, and he was at risk of hurting his leg every time he went to get up on all four feet, should he twist it or tweak it wrong. Another complication we dealth with was bed sores. Poor JB had the most horrible hock sores that I battled with every lotion, cream , salve under the sun to try to keep from reopening. As soon as they would start to heal, he would tear one open again in the process of pushing off his hind legs to get back on his feet. He got pretty sore on his hocks and while I think he knew I was trying to help with the goop I was constantly trying to apply, he preferred to not be touched much at all back there. We came to an agreement eventually but not before he managed to catch me a time or two from kicking out. Did I mention the little bugger has fast little hind feet?? I sustained more kicks from JB in those weeks than I have ever received from any horse. In one case, he caught the inside of my left knee. I got lucky that day, it was not a hard enough kick to injure my knee joint, just the tissue around it. That knee swelled like a balloon and turned some of the most putrefying colors…. So… Hardship??? yah, you could say that…Beware, your sweet horse you once knew will tend to get ornery at times...
Tendons connect muscle to bone, providing elasticity and increasing both gait efficiency and support to the lower limb alignment. Ligaments connect bone to bone, giving structural support for joints and maintaining suspension of the fetlock joint as part of the suspensory apparatus in the horse. Tendon and ligament injury can be classified into three categories: traumatic laceration or rupture; acute inflammation with swelling and pain (tendinitis); and a more subtle degenerative injury due to a failure to heal due to repetitive damage
JB fell into the first category , traumatic laceration or rupture but the interesting point here that caught my attention was Gait efficiency and gait, in general. With an endurance horse, it’s kind of important to have a horse be able to pass a vet exam so you can participate. In order to cover mile after mile, gait efficiency is very important. With the Pastern fusion procedure, JB is essentially now missing a key joint that provided cushion from impact.
We better do a quick anatomy lesson before I go much further:
The procedure fused the First and second Phalanx bones , or a.k.a. short and long pastern bones.
So what does this joint really do?
From the bottom of the cannon bone, the long pastern bone (First Phalanx)is the first bone we are talking about. It’s called a long bone because it has a central marrow. It is angled between the cannon bone and the short pastern bone and acts as part of the shock absorbing mechanism of the leg. The top of the bone is deeply grooved and divided into into two articular surfaces, which fit snugly together with the lower end of the cannon bone forming the fetlock joint. The lower end of the long pastern is also divided into two articular surfaces, the inner surface larger, but the line of division is not as distinct as the upper end. On the front surface of the bone is a bulge where the common digital extensor tendon attached. The superficial flexor tendons are attached at the back, on either side.
Below that lies the short pastern bone(second Phalanx) is a solid bone with no central marrow. It is important because it is partly inside and partly outside the wall of the hoof and also because it is the first bone to sustain concussion as the foot hits the ground. The short pastern is also an angled bone and is supported at the back by the deep flexor tendon. The superficial flexor tendon is also attached to the back surface and the common extensor tendon is attached to the front surface, just like the long pastern bone.
With a pastern Arthrodesis, the biomechanics of the joint change and the surrounding ligaments, tendons and joins will take on an additional burden. That means, JB's way of travel may always look a bit different. At this time, it’s hard to tell how JB’s body will adjust to this change. To call it lameness, right now, we probably could. Hopefully in time, that will lessen.
My vet and I discussed this part at length, given my hopes to return JB to limited distance or at best, longer distances, maybe real endurance?? In order for him to ever stand a chance at passing a vet exam at a ride again, his way of going will have to improve. As the vet indicated, given how well the fusion is healed in the xrays, he was surprised that JB had a slightly shorter step on the right side.. It's not something my vet wants me to worry about right now. When it comes time to start riding JB here in a couple of months, my instructions are to not let that short step deter JB returning to light work (to start). It could very well be something higher, something soft tissue in the knee or shoulder. It would stand to reason , given the position JB had himself in when he got injured and that he struggled badly. Could just be a soft tissue injury, and we all know how long those can take to heal. The bottom line is that all the indicators are there that he will return to full use. It will be a matter of working JB gradually back into fitness and seeing how he reacts each time. My plan is to take it slow, track his progress with each ride over a period of time and adjust where we need to.
The connective tissues from which tendons and ligaments are made are closely related. The highly organized structure of tendon enables it to be both strong and elastic. The cells within tendon produce the extracellular matrix that is organized into the fibers responsible for tendon's unique mechanical properties. The tendon fibers are made of the protein collagen (predominately type I). The collagen forms long interlaced fibers in the same alignment with the tendon length, but the fibers also have a pleated pattern termed "crimp" that, like a spring, gives elasticity to the tendon.
When a tendon is injured, tendon fibers are ruptured or degraded by the inflammation. Attempts at healing frequently fall short of the exact structure of normal tendon. Abnormal orientation, size and organization of the collagen fibers that replace the original structure have less strength and elasticity. This is thought to increase the risk of re-injury once the healing process is over.
Most of this doesn’t really apply to JB because the MCL is no longer part of JB’s anatomy. However, there are other ligaments and tendons to be watching as he returns to work. Re-injury is always lurking in the back of my mind. There are some things I am doing to help decrease that as much as possible and I will get to that in a minute. I don't even want to think about the word re-injury!
Because of the large amount of tissue matrix, tendons, and ligaments have a relatively small number of blood vessels and cells that can make new normal tendon. When the tendon is damaged, the injured fibers and matrix need to be degraded and removed during the inflammatory process. It is thought that poor healing in tendons results from a prolonged and inefficient inflammation needed to remodel the tendon and prevent scarring. Therefore, tendon requires as long as nine to 12 month for complete healing. Even with a careful rehabilitation program, re-injury is common.
Like tendons, injured ligaments can have a painfully slow healing process. We’ve probably all dealt with a bowed tendon? Now amplify that by about 10 times with a MCL or suspensory injury. If I opted to let time heal JB’s ruptured MCL, the outcome would have likely been poor. The ligament would have healed eventually on its own, in some fashion, but the likelihood of soundness were very low with pain and arthritis being very high. In the end, JB’s ruptured ligament was too severe for any hope with this approach, even with careful rehabilitation. Typically , it’s a torn or lacerated ligament injury, the outcome of letting them heal on their own is usually better. Arthritis on the other hand is always a factor in these cases.
Both acute and chronic degenerative lesions in ligament occur in all equine endeavors, with suspensory ligament injury (desmitis) being the most common. Suspensory ligament desmitis can cause a chronic lameness and be resistant to currently available treatment modalities. Also, because current therapies have not been compared to each other or proven, it is often difficult to know which one gives the best chance for complete healing.
In reality JB's suspensory ligament could be impacted.This is because the pastern fusion changes the biomechanics of his pastern joint. The vet isn’t overly concerned that he will have any issues, but if he goes back to work over distance, it will be something I need to be paying attention to. I may consider using SMB boots for support. My vet is consulting with a sports medicine vet on whether this will be helpful or not for JB. Stay tuned for updates on this topic. Or, if anyone has any input on this, I would love to hear about it.
There are more and more studies coming out about using stem cells for tendon injuries in horses. This procedure is actually increasingly being used in a number of clinical practices with some impressive results. There are two types of stem cell therapy, one is Mesenchymal stems cells (MSC’s) which are obtained from the horses own bone marrow. The procedure is invasive. The process then takes several weeks to culture the cell before they can be reinjected directly into the damaged tendon. The other therapy is Embryonic stem cells (ESC’s) This therapy is very new in treating horses with tendon injuries. The initial studies being done are showing a higher survival rate of the cells in the 10 day post injection period. It’s still very early in the process to know how effective they will be but the studies suggest that ESC’s could be a very viable option in the near future for tendon injuries. ESC’s can be used “off the shelf” unlike MSC’s.
Interesting stuff that I will likely continue to read up on.
Of course, there are other risks I am going to have to do my best to dodge. Arthritis in the surrounding joints (won’t be in the fused joint, for obvious reasons…).Through out his recovery I kept JB on a supplement for Glucosamine, Chondroitin Sulfate , Hyaluronic Acid , MSM and Vitamin C. It’s a product through SmartPak called SmartFlex Reapir. It helped give him everything he needed for joint, tendon and ligament health during his recovery period. It wasn’t just his injured leg I was supporting. I wanted to support his other joints as well during his healing. He was stall bound for 4 weeks prior to his surgery and then 6 more weeks after that. The skeletal structure of a horse is designed for movement and without that, there is a risk of negative impacts to his other joints and tendons. I wasn’t sure if supplementation would help in the long run, but I wasn’t sure it wouldn’t help either. It was kind of like purchasing a little insurance. It certainly couldn’t hurt so there was nothing to lose. One thing I am certain of is that it kept inflammation down with the MSM. Low inflammation translates to increased healing.
Our understanding of how some degenerative and acute injuries are related to each other is incomplete. The current thinking is that a low level of damage or degeneration occurs in the tendon or ligament over time. This damage is not completely repaired and can go unnoticed, because there may be no lameness, pain or swelling.
The failure to completely heal may be due to the inability of tendons to remodel or because of the repetitive forces these structures experienced regularly during exercise. Then, at a critical point during exercise or overexertion, the low-grade injury can no longer hold up to normal use or perhaps to an overload, creating an acute lesion with heat, swelling and lameness. This injury typically starts in the center or core of the tendon (called a core lesion), where blood and serum form a clot that replaces the tendon fibers and creates more inflammation that results in more damage over the following days or weeks.
This paragraph points out why I am concerned about JB's suspensory ligament and the other supporting structures. It will be interesting to see how he progresses as those other tendons and ligaments begin to be stressed once he returns to regular exercise. I have very little concern about the fused joint itself as it has healed very solid. I have discontinued the Smart Flex Repair product since his x-rays, but will return to using a similar product for maintenance once JB goes back to work in an effort to continue to support those structures.
The diagnosis of tendon and ligament injuries has improved dramatically in recent years. Several newtreatment modalities are being used, a long lay-up period and the risk of recurrence are still factors for recovery. Newer treatments such as injection with stem cells or platelet-rich plasma are promising,as mentioned above, but their benefit has not been fully understood.
Other treatments I have and will continue to utilize is chiropractic and massage therapy and, even craniosacral therapy. JB had three craniosacral therapy session with a craniosacral therapist who works on large animals (imagine!), in the weeks after his surgery. The purpose was to help reduce inflammation and pain. Again, I have no idea if it truly helped or not but I was willing to do whatever I could for a successful outcome. Fortunately, I have access a very good, LEGITAMATE equine chiropractor who travels to this area for individual sessions. I have been taking horses to him for several years, including JB. You can be sure we’ll be on his list next time he swings through this area.
Further research into the detection, causes and best treatments for tendon and ligament injury are all needed. In a survey of American Association of Equine Practitioners members by the AAEP Foundation in 2009, musculoskeletal disease was ranked No. 1 as the equine body system that needs further research. Additionally, 75% of respondents believed more research is needed to specifically help treat tendon and ligament injury. Though there has been much attention given to arthritis research, relatively little research has been directed toward tendon and ligament injury.
The importance of tendon and ligament injury cannot be understated; it can be responsible for the development of joint disease and is frequently associated with navicular disease. Research on tendon and ligament injuries will to help prevent and treat this cause of lameness.
I did a lot of research regarding the procedure and the recovery period . When I was first researching the Pastern Arthrodesis surgery, living on a fence for those weeks, trying to make a decision, I was frustrated at the lack on information out there on this procedure and the associated recovery rates. I was hungry for information beyond what my vets and consulting vets were telling me. I found a few studies that had been done, none of which were all that helpful because the study was outdated and focused on a comparison of techniques used with different types of hardware and placement of hardware relative to success. Of course the techniques that they were researching in that study are now standard practice as far as what kind of plate and screws are used and how the screws are placed. It was only one study, and not useful in what I was after.
I wanted to know what to expect, what to be prepared for, the good the bad and the ugly. How often did horses really return to full use? What kind of full use? Were we talking Jumping, roping, endurance, dressage , endurance? Or were we talking occasional arena /trail horse? What about the difference in breeds? Small horses versus big horses? Does one heal better than the other? Have there ever been any other endurance horses that have done this and returned to full use? Ideally I would have liked to talked to a few horse owners that had had this exact surgery done and hear what their experience was. There just wasn’t much to be found and I felt as though I had to make my decision in a vacuum, hoping for a positive outcome. I would certainly agree that more research should be done in this area. I would even be willing to have JB’s progress as part of a study for recovery rates, if there ever was such a thing…
Rehab for a Pastern Arthrodesis (fusion of first and second Phalanx )is a bit different than Rehab for a tendon or ligament injury, although they they share some similarities. The time period is almost the same 9-12 months for optimal healing, sometimes longer. Injured tendon or ligament cannot withstand sudden heavy loading during this time and is highly susceptible to re-injury. Same with pastern arthrodesis. An example of a controlled exercise program is described below for a tendon/ligament injury. By gradually loading the tendon/ligament in increasing amounts, you are stimulating the tendon/ligament to heal to the best of its ability. With Pastern arthrodesis, impact to the joint was what was going to trigger the fusion, because bones respond to impact. Think about foals, they should have access to run and play for the best development of their skeletal and mucle structures . So, our rehab for JB was a bit of a spin off of this program once he was released to start hand-walking and ponying. In addition, JB has slowly been graduated to larger and larger paddocks so , by default, rehabbing himself.
**It is important to remember that this program noted below is to be used as a guide. Each horse is different., depending on the structure involved, severity of initial injury and progression of healing.
Controlled Exercise Program
0-60 days- handwalking )clock started at 5 mos post op for me
60-90 days - 5 minute trot/jog
90-150 days - 10-15 minute trot/jog
150-210 days - 20-25 minute trot/jog
210-240 days - canter 5 minutes / gallop 1 mile every other day (racehorse)
240-270 days - canter 10 minutes / gallop 1 mile every day (racehorse)
270-300 days - low jumping / short breeze (racehorse)
300-330 days - normal jumping / breezes (racehorse)
330-360 days - competition
WIth tendon and ligament specific injuries, recheck ultrasound exams are performed every 60 days to assess healing and to prevent reinjury. Ultrasound can detect evidence of tendon or ligament damage before a new injury occurs. In this case, the horses exercise level is reduced to prevent further injury. It is important to remember that horses should not advance in their exercise program without re-evaluation by a veterinarian.
With Pastern Arthrodesis, they did xrays when the surgery was completed to show placement of the hardware and then xrays again at the 6 months post op time. JB shouldn't need any more xrays unless something goes wrong.
PROGNOSIS- WILL MY HORSE BE ABLE TO RETURN TO HIS JOB?
At this point in time, JB’s orthopeadic surgery has been , a very positive outcome. My vet is very pleased with his progress and how everything has healed. He also feels that his chances are very good that he will return to distance riding. He may never be a 50 miler or a 100 miler but we just don't know yet. Lastly, I wanted to share a few key things I felt were most influential in having or getting a positive outcome.
1) Make sure your horse can handle being confined for a long time. If you don't think he can, either opt for keeping him medicated or don't go through with it. I kept JB lightly sedated, (enough to take the edge off) for the time he was in his cast.The longer the horses can keep the cast on the better the chances are for healing correctly.
2) Make sure the surgeon doing the procedure has alot of experience with it
3) Get several opinions, talk to as many people as you can about it.
4) Set it up so you can bring your horse back to the environment he is most comfortable in and make sure he is comfortable. It will keep him less stressed and less risk of injury during recovery. If that place is a boarding facility, make sure you or someone else you trust can be monitoring him daily at the minimum , ideally multiple times during the day. Things like your horse getting cast in his stall can be a huge set back. Monitor his eating, peeing, pooping, and his attitude. Make changes as you need to.
5) While in a stall, give your horse something to keep him occupied. For JB, I had a radio going, a fan to keep him cool, and I kept a quiet horse in a paddock about 20 feet away that he could see at all times. Every day, I would bring a horse over to JB's stall just to let JB make contact with another horse over his stall wall. They are herd animals and seek comfort in their herd mates. I also picked JB buckets upon buckets of green grass every day. You might consider hanging a "lik-it" toy to hang from the ceiling as well. I hung a ball that JB played with a little but it wasn't really his gig.
6)Give your horse the best possible feed you can and keep hay in front of him as much as possible. You may also want to supplement.
7)Supportive care like massage or craniosacral work. I also rubbed JB's other legs down every evening with arnica gel, especially his front left leg and his right knee , which was getting alot of pressure when he was in the cast.
8) Spend time with your horse during his recovery, as much as you reasonable can. At the risk of sounding a little woo-woo, talk to your horse in calming tones, tell your horse he/she is going to get better and that this is temporary. Use this time as an opportunity to bond. They understand more than you realize.
9) Keep your horse clean and his bedding clean. JB was groomed every day and because he couldn't roll while he was stalled, he especially enjoyed this time to get the itchies taken care of. I also cleaned his stall morning and night for all 10 weeks of his time being in a stall.
9) Keep a positive attitude- they can sense things we have no idea about.