A REVIEW OF CURRENT JOINT THERAPIES
Regardless of the joint(s) involved, our therapeutic goals are the same:
1) To modify the symptoms by reducing pain and lameness, and
2) To modify the disease by discouraging progression of joint deterioration.
Let's review our options when it comes to treating general joint pain in the horse. These include:
I. CORRECTIVE SHOEING
In most cases, we can trim and shoe the horse in a way that minimizes challenge to affected joint(s). Our goal is to make the arthritic joint work as little as possible while still maintaining normal overall movement and function. In order to do this, we have to optimize the way the joint moves and bears weight during exercise. Corrective shoeing can counteract some of the abnormalities that contribute to joint instability.
We frequently manipulate joint movement and weightbearing by implementing one or more of the following techniques:
a) Facilitating breakover. Easing breakover often decreases the degree of flexion and extension the joint undergoes during exercise. For the most part, less movement of this type reduces the joint's predisposition to
instability. Less instability results in less inflammation and improved overall comfort.
b) Normalizing joint angle. Arthritic joints often have abnormal angles relative to the rest of the limb. Joint angles can be deranged from front-to-back and/or from side-to-side. Minimizing these derangements can enhance joint stability and improve comfort.
c) Equalizing joint pressure. Most joints are designed to bear weight uniformly across the entire articular surface. Abnormal joint balance and/ or limb movement can alter these forces, resulting in excessive compression on one side of the joint and tension on the other. Normalizing pressure across the joint surface discourages abnormal wear of the articular cartilage.
d) Reducing joint compression. Excessive compression across the articular surface can affect the metabolism and wear of the articular cartilage. For example, lighter horses are less predisposed to joint problems as to compared to heavier horses.
e) Maintaining normal motion characteristics of the joint. The joint is happiest when the flight path of the limb is straight and the limb is directly in line with its center of gravity. The position of the limb both on the ground and in the air can be manipulated via shoeing.
II. SYSTEMIC ARTHROTHERAPY
Several advancements have been made in the field of systemic joint therapy over the last decade. We will review a few of these strategies.
Any medication administered outside the joint (by mouth, intravenously, or intramuscularly for example) for the purpose of improving joint function and/or comfort is considered a form of systemic arthrotherapy. Anti-inflammatory medications (such as phenylbutazone and Banamine), topical pain relievers (such as capsaicin and diclofenac), and joint supplements (such as Adequan®, Legend®, and Cosequin®) are included in this category.
Joint supplements have seen wide use in recent years, and are most often the client's first line of treatment for DJD in their horse(s). The primary goal of the joint supplement is to stimulate normal activity and function of the synovial membrane thereby enhancing the integrity of the joint environment. Topical, oral, intravenous, and intramuscular forms exist.
1) NONSTEROIDAL ANTIINFLAMMATORY DRUGS (NSAIDs)
Non-steroidal antiinflammatory drugs (NSAIDs) such as Bute, Banamine, Ketofen, etc.) are frequently used to alleviate the clinical signs (namely inflammation and pain) associated with arthritis in horses. However, consistent use can result in gastric ulceration as well as kidney and liver dysfunction. Therefore, we recommend this form of therapy only for horses that perform very infrequently, such as once or twice weekly (or less).
There is a relatively new product called EQUIOXX (firocoxib) that was developed by Merial. Equioxx has been shown to reduce inflammation and pain associated with osteoarthritis in horses. At the same time, it offers a much better safety profile when compared to other (more traditional) NSAIDs. Equioxx is the first coxib class nonsteroidal antiinflammatory drug that is highly selective against Cyclooxygenase-2 (Cox-2) prostaglandins which are responsible for inflammation. Unlike other NSAIDs, however, Equioxx spares the beneficial Cox-1 prostaglandins required for normal gastric, renal (kidney), and hepatic (liver) function. A single dose lasts for 24 hours and can be administered for up to 14 days in a row. Equioxx comes in an oral paste form; each tube contains 1500 pounds of medication. Each marking on the syringe treats 250 pounds of body weight, and each notch corresponds to a 50-lb weight increment. Equioxx can be administered with or without food. Equioxx can be ordered through our Pharmacy by calling 678-867-2577 or by contacting email@example.com
For more information, contact our office or visit http://www.equioxx.com/
At The Atlanta Equine Clinic, we have observed a comparable effect of a much lower (and less-expensive) dose of the small animal preparation of firocoxib, known as PREVICOX, to that of its large-animal counterpart (Equoxx). In our experience, a 57-mg dose of Previcox (which costs less than 67 cents) produces similar clinical results to that of an extire tube of Equioxx (which costs $9.75). This product can also be ordered through our pharmacy.
SURPASS® (diclofenac sodium) is a topical medication that has gained popularity in recent years due to its ease of administration (simply rub it on the affected joint) and its effectiveness for certain types of arthritis in horses. In our experience, Surpass generally works better under the following circumstances:
a) In higher-motion joints. For example, we would expect a better response when treating a fetlock joint (which is very high-motion in nature) than we would when treating the lower hock joints (which are very low-motion in nature).
b) In joints that are closer to the skin surface. If there is less tissue through which the product is required to diffuse then more will be delivered to the affected area. Consequently, we would anticipate a better clinical response if more product is reaching the joint. For example, we would expect a better response when treating a fetlock joint (which is just under the skin surface) than we would a stifle joint (which is much further/ deeper from the skin surface).
c) In joints with a high topical surface area:size ratio. We typically observe a higher concentration of therapeutic medication in synovial (joint) tissue (and therefore a better clinical response) when the joint is smaller and very well exposed under the skin surface. For example, we would expect a better response when treating a fetlock joint (small and just under the skin surface) than we would a stifle joint (large and deep under the skin surface).
d) When used prophylactically (as a preventative) rather than subsequent to the onset of joint inflammation. In other words, we would expect a better response if we applied the product prior to exercising the horse than we would if we applied the product after we finished riding.
For more information, please visit
2) ORAL JOINT THERAPIES (i.e. Given by Mouth)
Most studies show that the oral medications (e.g. Cosequin®, MSM, Flex Free®, Corta-flex®, etc.) are quite effective when absorbed into the system. This type of arthrotherapy works especially well in people and dogs, who are able to absorb relatively large molecules (like glucosamine and chondroitin sulfate) through their intestinal wall easily. Horses, on the other hand, are generally not proficient at absorbing large molecules into their system from the intestinal tract. Therefore, a portion of the oral medication (and the client's investment) may not be completely utilized. Many companies are continually working to find ways to improve absorbability of oral supplements in the horse.
In many cases clients are limited to the administration of oral medications due to various circumstances which include barn protocol, difficulty/ danger in administering shots, lack of adequate assistance and/or restraint, etc. In our opinion, one of the best oral medications for the money is called MEGA-FLEX and is produced by Spectra Animal
Health. Please visit http://www.americanlivestock.com/m-15147-.aspx for more information.
3) INJECTABLE JOINT THERAPIES
Medications which bypass the intestinal tract of horses (and therefore do not rely on intestinal absorption) are generally preferred at present. These are injectable (i.e. given as a shot) and include both LONG-TERM/maintenance and SHORT-TERM forms.
SHORT-TERM medications are administered intravenously (IV) and therefore typically have a greater positive effect on joints. In other words, we generally observe more improvement in the horse's comfort following administration of short-term therapy (such as Legend®) than we do following administration of long-term therapy (such as Adequan®). The positive effect of short-term therapy, however, is only about one-half as long as that of long-term therapy.
It is for this reason that we recommend short-term therapy and long-term therapy with different goals in mind.
We currently recommend LONG-TERM joint therapy for the following:
a) In horses with no current evidence of joint disease. The purpose of the medication is to delay the onset of joint disease.
b) In horses with mild joint disease. The purpose of the medication is to alleviate symptoms enough for the horse to perform well in his/her intended capacity.
c) In horses with moderate to severe joint disease that have previously been treated with local therapy (i.e. injection). The purpose of the medication is to prolong the effect of the injection and delay the recurrence of clinical signs.
Long-term/ maintenance medications include Adequan®, Acetylglucosamine, Chondroprotec®, Pentosan and Glucosamine (among others). Most treatment protocols involve one injection (5cc or 500mg) in the muscle once weekly for 4 consecutive weeks and then once or twice monthly thereafter (indefinitely). Cost varies anywhere from $12 to $50 or more per dose.
The ATLANTA EQUINE CLINIC is currently conducting an informal RESEARCH STUDY on the effects of intramuscular PENTOSAN in the horse. Click HERE to learn more about the study.
CONTACT US if you have any questions or to find out if your horse(s) may be eligible to participate in the study.
Participating clients will receive a 20% discount on Pentosan for EACH horse enrolled in the study, which amounts to less than $16 per dose.
Any of these products can be ordered through our pharmacy at 678-867-2577 or firstname.lastname@example.org
We recommend SHORT-TERM joint therapy for the following circumstance:
a) 36-48 hours prior to a race, clinic, or show. The purpose of the medication is to maximize the performance of the horse for a selected event.
Short-term medications include Legend, MAP-5, and (among others). These medications are generally administered intravenously (in the vein) at varying doses. The cost of a single dose can range from $35 to $95. In our opinion, the best product for the money is a generic version (MAP-5) which runs $75 for 50mg (versus $95 for 40mg Legend).
These can also be ordered through our pharmacy.
If regular short-term treatment (i.e. an IV dose administered every 2-4 weeks or sooner) is required to produce and/or maintain soundness or does not result in a satisfactory response, then local arthrotherapy (i.e. joint injection) may be considered.
4) TILDREN® (TILUDRONATE)
Tildren is designed to normalize bone metabolism, thereby alleviating clinical signs associated with osteitis (bone inflammation) and osteoarthritis (joint inflammation).
Healthy bone undergoes continual metabolic readjustment in response to stress/ exercise. Bone is constantly being broken down (via osteoclastic activity) and rebuilt (via osteoblastic activity). Normally, there is a balance between bone loss and bone redevelopment. Some pathologic conditions (disease processes), however, can result in excessive bone loss (known as "osteolysis") and/or abnormal bone remodeling (cell turnover). Horses with chronic navicular inflammation, for example, often experience abnormal bone remodeling as well as development of osteolytic lesions (areas of bone loss) within the navicular bone. These lesions are visible radiographically and may represent an imbalance in bone metabolism (i.e. increased bone resorption relative to bone redevelopment).
"Tildren" (or tiludronate) inhibits excessive bone resorption and promotes rebalancing of bone metabolism. At The Atlanta Equine Clinic, the use of Tildren has proved beneficial in cases of navicular inflammation, nonadaptive bone remodeling, and severe osteoarthritis.
4) OSPHOS® (CLODRONATE)
Dechra's OSPHOS® is an injectable bisphosphonate solution which implements a similar mode-of-action as Tildren®.
OSPHOS® (clodronate) inhibits bone resorption by binding to calcium phosphate crystals (inhibiting their formation and dissolution) and by exerting direct cellular effects on osteoclasts.
Unlike Tildren, however, OSPHOS® has the unique advantage of intramuscular injection and is a ready-to-use solution that does not require mixing or reconstitution. It is also considerably less expensive than Tildren®.
III. LOCAL ARTHROTHERAPY (JOINT INJECTION)
Joint injection enables us to deliver high concentrations of therapeutic medication directly to the synovial membrane of the affected joint(s). The synovial membrane is responsible for producing hyaluronan (hyaluronic acid/HA) which is responsible for lubricating and protecting the articular cartilage. The synovial membrane is also responsible for the release of inflammatory cells in joints that are compromised.
When performing joint injection, veterinarians usually elect to infuse a combination of synthetic hyaluronan and corticosteroid. Steroids effectively eliminate inflammation within the affected joint and hyaluronan serves to reestablish a normal synovial environment.
Many clients are concerned about the effects that corticosteroids will have in their horse's joint(s). This concern is primarily a consequence of reports of accelerated joint deterioration pursuant to abusive use of steroids in racehorses.
There is no question that corticosteroids can have deleterious effects in the equine joint. However, we should consider the whole picture when considering its use in the performance horse:
Let's say we don't infuse steroid into the joint. The inflammatory cells will persist in the joint. As a result, the following consequences will occur:
a) The presence of the inflammatory cells within the joint will increase the hydrostatic pressure within the joint causing the influx of fluid. Increased synovial fluid in the joint (called effusion) results in stretching of the joint capsule (which houses nerve endings) and pain. So lameness will persist.
b) The inflammatory cells release degradative enzymes (called lysozymes) and other chemical mediators that break down hyaluronan (HA) within the synovial fluid. The fluid becomes very thin and watery, thereby losing its ability to protect the cartilage. Consequently, we get erosion of the cartilage which in turn results in increased joint instability,
inflammation, and so on.
In other words, persistent inflammation is not healthy for a joint!
Let's say we infuse steroid into the joint. The presence of steroid will reduce inflammation within the synovial environment. As a result, the hydrostatic pressure will decrease, fluid will leave, the joint will decompress, and will be more comfortable. Furthermore, there will be less degradation within the joint due to the absence of the inflammatory enzymes and mediators. Therefore, in one sense, steroids are helping us to IMPROVE synovial integrity.
On the other hand steroids also result in breakdown of HA which, as we previously discussed, is chondroprotective (protects the cartilage).
Therefore, we must weigh both sides.
The factors that determine if intraarticular injection using steroid is indicated include:
a) How important is the integrity of this joint in regard to the soundness of the horse? Is it a high-motion joint? Is it a high-weightbearing joint?
The thoracic (front) fetlock most important joint in the horse. Per unit area, it is the highest-motion and bears the greatest amount of weight when compared to other joints. This joint must be comfortable and have a normal range-of-motion for the horse to be sound. When treating this joint, we should do it in a way that promotes excellent synovial integrity and health.
The distal hock joints, on the other hand, are probably the least important joints in the horse. They move very little during exercise, and are not necessary for normal locomotion of the limb. In fact, if the horse did not have these joints (in other words, if there was solid bone in place of the joints) we would not be able to detect any gait abnormaility. We sometimes elect to surgically or chemically fuse these joints in horses that are refractory to other forms of therapy. Veterinarians, therefore, have the luxury of being quite aggressive in regard to therapeutic strategy without the concern of imposing deleterious side effects. When it comes to these joints, our primary focus is not maintaining good synovial integrity but rather keeping the horse comfortable and sound. It is for this reason that hock injections are far more common than any other type of joint injection.
If you would like to learn more about DISTAL TARSITIS (the hock problem), click HERE.
b) How much inflammation is present?
Inflammatory changes can eventually become irreversible. This leads to greater joint disease and further inflammation. The deleterious effects of inflammation may outweigh those that occur pursuant to steroid injection. In many cases of joint disease, intraarticular steroids are HEALTHIER for the joint than a lack of steroids. In other words, the benefit of steroids outweighs the deleterious side effects.
If you would like to learn more about DEGENERATIVE JOINT DISEASE, please click HERE.
2) ADEQUAN® I.A. (polysulfated glycosaminoglycan)
This product obtained the approval of the Food and Drug Administration (FDA) for intraarticular injection in 1984. It is the ONLY joint therapy clinically proven to relieve symptoms associated with arthritis andtreat the underlying causes of equine non-infectious degenerative joint disease.
We have observed good results with this product over the past 10 years and have had no complications pursuant to using it on our clients' horses.
Unfortunately, however, inflammatory joint reactions and septic arthritis (joint infection) have been reported following administration of Adequan® I.A. Studies suggest that Adequan IA potentiates joint infection, which is a rare but potentially life threatening complication.
To reduce the likelihood of complication, most veterinarians infuse Adequan IA in combination with antibiotic (usually Amikacin) into the joint. Although this approach dramatically decreases the risk of developing post-treatment septic arthritis, we have found that the presence of intraarticular antibiotic can result in synovial irritation/ inflammation. Therefore, the addition of antibiotic to the treatment regimen actually diminishes the positive effect of the injection.
It is for this reason that we typically select a different product for intraarticular use in the horse.
It should be noted that there is no correlation between administration of Adequan IM (the intramuscular form) and septic arthritis (joint infection). We frequently use Adequan IM as part of our long-term arthrotherapeutic strategy.
For more information, please visit: http://www.luitpoldanimalhealth.com/Adequan_ia.html
3) LEGEND® (hyaluronate sodium)
This product is the only FDA approved intravenous and intraarticular therapy designed to treat equine non-infectious synovitis associated with osteoarthritis. It is a preparation of pure hyaluronate sodium, the same glycosaminoglycan present in normal joint fluid. Legend is produced by a patented biofermentation process, resulting in such purity that it can be given intravenously for immediate bioavailability.
We have observed excellent results when using Legend intravenously in our practice. The effect of IV injection peaks in about 48 hours and lasts for approximately 2 weeks.
Since there are preparations of hyaluronan available with higher molecular weight at comparable expense, we usually do NOT implement Legend in our joint injections.
For more information, please visit: http://www.bayerdvm.com/products/legend/legend.cfm
4) MAP®-5 (hyaluronate sodium)
MAP-5 is a patented salt of hyaluronic acid in normal saline for use in the collection, handling, culture and cryopreservation of embryo, ova, sperm and other cells. Although this product is licensed for use as a cryopreservative, it has proven to be very effective as an off-label treatment for equine arthritis.
We often recommend MAP-5 for IV use in place of Legend, as it seems to have a comparable effect and is considerably less expensive. It can be administered both intravenously and intraarticularly.
For more information, please visit: http://www.drugs.com/vet/map-5.html
Polyglycan is a highly viscous aqueous solution of defined fractions of purified Hyaluronic acid, Chondroitin sulfates A-and-C in a 10% solution of N-acetyl-D-glucosamine. Some clients consider this product to be a combination of Adequan and Legend. Although this is not exactly accurate, Polyglycan does contain components that are representative of both.
Polyglycan was initially developed as a post surgical joint lavage with the goal of quickly reestablishing synovial physiology following arthroscopic or arthrotomic surgery. Polyglycan contains naturally occurring components of synovia that play a central role in maintaining the homeostatic environment of the joint.
Soon after it's introduction into the equine market, however, off-label intraarticular and intravenous applications quickly popularized.
In our experience, Polyglycan has comparable benefit to Legend with respect to both intravenous and intraarticular administration. Some clients think that it works better than Legend when administered intravenously (IV), although this comprises the minority of opinions.
We do implement Polyglycan intraarticularly for post-surgical cases, although typically elect to use high-vicosity hyaluronan (i.e. Hylartin or Hivisc) as part of our intraarticular protocol in horses with chronic joint disease.
Some lay-people (not our clients) have complained of excessive hemorrhage/ bleeding as a result of Polyglycan administration, although these reports are highly-speculative and there have been no clinical observations to this effect.
For more information, please visit: http://www.arthrodynamic.com/polyglycan/index.php
6) SODIUM PENTOSAN POLYSULFATE (PPS)
PPS is a linear polymer prepared from xylan, a complex hemicellulose extract of plant (Beechwood) origin. PPS is one of the sulfated heparinoid compounds. The heparin-like anti-coagulant effects have been reduced and the anti-inflammatory, fibrinolytic, and tissue trophic effects have been enhanced.
It is administered both intramuscularly (IM) and intraarticularly (IA) in the horse.
In addition to promoting synovial intergrity and inhibiting enzymal degradation of the joint, Pentosan may have increased antiinflammatory effect as compared to other products. This quality may obviate the need for concurrent use of intraarticular corticosteroids, upon which which many veterinarians rely for their potent antiinflammatory properties. The potential deleterious effects of intraarticular corticosteroids on articular cartilage have been well-documented.
In our experience, Pentosan alone does not produce a positive clinical effect comparable to that of a hyaluronan/steroid combination. The antiinflammatory effects of corticosteroid appear to be much stronger. This observation coupled with our current ability to use relatively "safe" (non-deleterious) articular steroids (such as Betamethasone) usually prompts us to implement a hyaluronan/ steroid combination during our initial treatment of equine arthritis.
Subjective opinions of Pentosan vary considerably among our clients. Some think that is makes a tremendous difference in their horse's performance; others do not observe any positive effect. Lack of effect may occur in lieu of the recommended dose of 3mg/kg being inadequate (too low). It is for this reason that we typically offer Pentosan as a second-line strategy to our clients that are willing to try it.
We should note that if a combination of hyaluronan and steroid has already been implemented unsuccessfully, it is unlikely that intraarticular Pentosan will prove to be effective.
For more information, please visit: http://pentosan.com/
7) AUTOLOGOUS CONDITIONED SERUM (ACS)
This product is marketed as "IRAP" by Arthrex Vet Systems.
The exploration of interleukin-1 receptor antagonist protein (IL-1Ra or IRAP) as a treatment for synovitis, osteoarthritis and rheumatoid arthritis began shortly after its first published characterization in 1984. The ability of this molecule to act as both a symptom- and disease-modifying agent in various species (including horses and humans) has prompted its clinical application as a treatment for joint disease. The goal behind IRAP treatment is to use the body's own inflammation-fighting cells to reduce arthritis rather than the synthetically-produced antiinflammatory medications that we buy in a bottle. Because antiinflammatory cells are produced by the host body itself, we can often expect an improved degree of response as well as a longer duration of response.
At The Atlanta Equine Clinic, we generally reserve IRAP use for those joints refractory to steroid treatment.
8) MESENCHYMAL STEM CELLS (MSC)
Stem cells are receiving a great deal of scientific attention as well as coverage in the lay press. The primary reason for the attention is the potential ability of stem cells to regenerate tissues without the production of scar tissue that is generally associated with healing processes. The goal through stem cell use, therefore, is to replace damaged tissue with something comparable to the original tissue rather than with scar tissue.
At The Atlanta Equine Clinic, we typically reserve stem cell use for those joints with relatively deep subchondral lesions.
9) PLATELET-RICH PLASMA (PRP)
Numerous growth factors have been used in the horse with the intention of enhancing synthesis and reducing breakdown of tendon/ ligament tissue pursuant to injury. Historically, these growth factors have been harvested from bone marrow and/or fat aspirates, which also contain increased concentrations of stem cells.
More recently, platelet-rich plasma (PRP) has been gaining popularity as a treatment designed to augment equine tissue repair.
Platelet-rich plasma (PRP) is an autologous concentration of platelets in a small volume of plasma. Plasma is the straw-colored liquid in which blood cells are suspended. PRP is generated through relatively simple centrifugation of blood. Because it is a concentration of platelets, it is also a concentration of 7 fundamental protein growth factors known to be secreted by platelets in response to wound healing. PRP also contains proteins known to promote cell adhesion during tissue rebuilding.
Platelets perform many functions in the body, including formation of blood clots and release of growth factors into wounds. The rationale for the use of PRP as a treatment strategy for tendonitis (tendon damage) and desmitis (ligament damage) stems from the increased platelet release of multiple growth factors in response to an injury. Two additional incentives for using PRP include its relative ease of collection and the unlikelihood that it will result in immune rejection since it is autologous (produced from the patient's own blood).
At The Atlanta Equine Clinic, PRP has been used to successfully treat the following soft tissue injuries: tendon strain, muscle strain, ligament strain, and joint capsular laxity. PRP has also been used to treat intraarticular injuries. Examples include arthritis, arthrofibrosis, articular cartilage defects, meniscal injury, and chronic synovitis (joint inflammation).
Diagnostic & Surgical Arthroscopy allows for direct visualization of the joint's interior. In many cases, abnormalities not readily visible radiographically (upon x-ray) or ultrasonographically will be apparent through an arthroscope. Once isolated, certain lesions (such as meniscal tears, bone chips or subchondral cysts) can be debrided under arthroscopic guidance. "Cleaning up" the joint in this fashion may help to reestablish the horse's soundness. Diagnostic/ surgical arthroscopy requires general anesthesia, however, and therefore must be performed within a hospital environment. Cost for the procedure varies depending on the type and location of lesion(s).
Please review our Postoperative Arthroscopy Notes HERE.