Options in Treatment for the Dysplastic Dog

Revised 2012

INTRODUCTION

I am frequently approached by people who have bought “the love of their lives” or a show- or working-prospect puppy, only to find out it does not have what most responsible fanciers would call “breedable” hips. I am asked what should or could be done about it. Nearly half of the inquiries include a potential litigious situation, since the pup was bought with an assumed “guarantee” (seldom any or anything worth the paper it’s on). In those cases, all I can do is tell them that I am available as an expert witness in court cases, but they should first try other means of forcing the seller to “make good.” I don’t want to get involved in arguments between seller and buyer outside of court (there are too many).

In this article, I intend to give you a picture of what I feel are the three best surgical repair methods (especially in puppies) and (even better) the non-surgical alternative to dealing with canine HD (hip dysplasia). The younger the pup, the more successful most surgical operations are likely to be. An orthopedic surgeon friend once described it to me exaggeratedly but almost perfectly: he said that with very young puppies, you could break all their bones, throw them into a bag and shake them, and they will heal. As dogs get older, healing and natural repair take longer (old people’s and dogs’ bones may not heal or fuse at all) and there is a lot more degenerative joint disease (degenerative joint disease [DJD], arthritis, “calcium deposits”) that cause inflammation and restrict motion.

TOTAL HIP REPLACEMENT

Femoral head and neck excision (removal) is usually limited to smaller dogs, though I know of a few Golden Retrievers who have managed quite well with that procedure. Muscles and ligaments take over in a partial way and form a “false hip joint.” It is used when simpler, less-invasive methods have not been satisfactory. Replacing the femoral head and the acetabulum with prostheses (man-made body parts) is considered another “last resort” salvage procedure, and once was recommended when the dog was too poor a candidate for the other treatments, yet the owner did not want to choose euthanasia. It became the chief surgical procedure in later years. Other salvage procedures restrict joint movement or remove the joint entirely, but a hip prosthesis can allow resumption of quite normal function, usually without any pain at all. People have been getting “artificial hips” since the early 1960s, although the very first total hip arthroplasty was performed in 1891 with an ivory ball and socket and nickel-plated screws. Dogs have been benefiting from the procedure for many years, and much more successfully after technical improvements around 1974.

While the major reason for hip replacement is to treat disabling HD, other disorders can also benefit: Legg-Calvé-Perthes disease, permanent dislocation from trauma, bad fracture of the femoral head and neck, hereditary or environmental defects in union of bone centers, and excision arthroplasties that have failed to solve the problem. Any candidate should be at least ten months old or the bone remaining may “outgrow” the size of the implanted prosthesis. Recently a “telescoping” femoral component was proposed that would lengthen as the pup’s leg continued to do so. While small dogs may reach skeletal maturity faster, or be close to their ultimate size earlier than large dogs, they are not as good candidates because their bones are too small to accommodate present synthetic parts. Dogs of very small size (under about 35 lbs) may do better with alternative treatment. Older dogs might be good candidates, if they still have enough of bone in the pelvis where the synthetic socket must be placed, and as long as owners realize the cost/benefit relationship. It wouldn’t make sense to implant a prosthesis if the dog was near the end of its natural lifespan or was suffering from some other ailment that might require euthanasia in the near future.One major producer of hip prostheses for dogs made two sizes: large and medium, which means that the percentage of bone and marrow removed would vary a little from one dog to the next, but not much. The endoprosthesis, which replaces the femoral head and neck, has a long stem that is inserted into a reamed hole in the diaphysis, the femoral shaft. A polyethylene plastic cup replaces the worn and shallow acetabulum. Another manufacturer introduced a promising modular total hip, and a third company introduced two advances on the type of implant. The femoral part of their cemented prosthesis is often made of cobalt chrome (a tantalum alloy may be better) and the acetabular part is at least partly UHMW (ultra-high-molecular-weight) polyethylene. In the non-cemented version, the acetabular part could be titanium coated with hydroxyapatite (the form of calcium phosphate of which bone is made). Some companies offered a cementless approach, also. Improvements are continually being proposed by one company after another, and the corporate identity keeps changing through mergers and takeovers, so the picture by the time you read this is probably different than it was.

Three models of replacement femoral heads with shaft that fits into a drilled femur.

There is also a variety of synthetic acetabulums on the market (right & center).

Here is one method that could even be outdated by the time you read this, but helps you to understand the general procedure. After the dog is made ready, the muscle layers incised, and joint capsule opened, the head of the femur is cut off at an angle corresponding to the angle of the prosthesis. The acetabular bed is prepared by another reaming process and several anchor holes are drilled in the depression. Then, in one method, polymethylmethacrylate cement (similar to the well-known “super” glues) is mixed with a powder and possibly antibiotics, and injected into these holes and the cup until level with the new rim. The prosthetic cup is positioned very carefully, as wrong angles or poor seating can result in dislocations and failure. Similarly, the shaft of the femur is filled with the glue before the femoral prosthesis is inserted. The excess cement that is squeezed out on insertion of the prosthesis is removed and the remaining cement gradually hardens, during which time it emits some heat from the chemical reaction of curing. This heat has been suspected of slightly damaging some adjacent tissue, especially that of the sciatic nerve. But, with care and experience, this damage is minimized and minor enough that the dog regains normal nerve function during convalescence. Later methods have done away with the need for the methacrylate cement.

The first month after surgery requires that activity be very limited, and very little more is allowed during the second postoperative month to prevent dislocations before the muscles and ligaments heal, although in many cases, the dog is walking on the day of surgery! If a dog passes the eighteen-month “milestone,” the prosthesis should last the rest of its life. Of course, there may be complications in some individuals, but the number has decreased markedly and is probably below 5% now. Most complications are dislocations and loosening of the acetabular component, but these can be almost completely controlled by careful positioning of the cup and proper care of the patient in the first few postoperative months. Infections present fewer (less than 1% failure rate) but perhaps more disastrous complications, and are treated by removing the cement and prosthesis and starting over again. These dogs do not recover hip function as fully as those who don’t need a repeat procedure.

Bilateral replacement is said to be necessary in about one fifth of the dogs undergoing this procedure. Most dogs put more weight on their “good” new hip, by rotating the pelvis slightly, in order to take the strain off the defective hip. In either case, bilateral or unilateral replacement, a dog with a new hip or two can return to almost completely normal activity, including some obedience jumping, jogging with the owner, and other play or work. However, if expected to do more work than guard the front porch and play, the dog should be put on an exercise program of gradually increasing demands. Too fast, and you can undo the reconstructive work. Recovery is graded as excellent if there is normal activity and no pain, good if some stiffness occurs after much work/exercise or prolonged rest, fair if there is still mild lameness and continued reduced weight bearing, and poor if there is continued and marked lameness. Recent results indicate that about 95% of these surgeries are excellent or good.

For a while, the major difficulty with THR was that the portion that was cemented or pressure-fit into the hole drilled in the femur would come loose. Improvements in design, surface, and techniques have reduced such problems tremendously. At the Canine Total Hip Replacement annual conference held in 2000 in San Diego, Dr. Gail Smith, chief of surgery at Penn, presented research data on a biocompatible, porous tantalum lattice called Hedrocel that is also osteoconductive (allows bone growth into its crevices and pores). Tantalum is a rare metal element, inert and thus quite non-reactive with body tissues or other chemicals. It offers application for orthopedic implants of various forms, and especially for bone ingrowth into structural implants such as total hip replacements. It is also being used as a trochanteric spacer to change angles and force/moment patterns in the hip, somewhat like the way a wedge driven into a saw-cut will cause a tree to lean in the desired direction. Bone ingrowth enables the body (with the surgeon’s help) to fix or attach an orthopedic implant device to bone. Bone cells growth into the “pores” of the metal implant. In the study reported on at San Diego, even the acetabular replacement was made from Hedrocel, with a UHMW polyethylene liner molded to it. By 8 weeks all but one of the dogs (GSDs) were without pain or limping, and all were symptom-free by 15 weeks after surgery.

PELVIC OSTEOTOMY AND OTHER PROCEDURES

A variety of other surgical techniques have been developed to treat HD, some of which do not seem to offer any improvement over the more commonly used procedures. Basically, you can cut the femur or cut the pelvis. First, we’ll look at procedures on the femur, but even before that, let’s review a few terms. When you see the ending “-otomy,” it refers to the act of separation by cutting: pectinotomy is the (scalpel) cutting of the pectineus muscle, while femoral or pelvic osteotomy is the (saw) cutting of bone in femur or pelvis. The ending “-ectomy” means cutting and removing, so a pectinectomy is the removal of a length of the muscle so it doesn’t grow back together, and ostectomy is the cutting off and discarding of a portion of bone. Osteotomy, as in the next examples, usually involves cutting bone (os-) and then allowing or helping it to grow back together in a different shape or angle. The form “my-” refers to muscle, so you will easily see the difference between tenectomy and myectomy (tendon vs. muscle).

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Varus osteotomy is an attempt to improve the angle of inclination so that the femoral head is better covered by the hip socket. A different osteotomy on the femoral neck changes the anteversion angle. This procedure is not always necessary, but unless it is performed, those dogs with the largest angles have the least satisfactory results with pelvic osteotomies. Both of these operations involve cutting the top section of the femur from the rest of the shaft, rotating it into a different position, then refastening the pieces together. Sometimes this cutting is done in three different planes to improve the fit of the ball into the socket. Femoral osteotomy in treating osteoarthritis of the hip joint has been described as occurring as early as 1894. This procedure, the TPO, shelf-building techniques, and other methods all are aimed at improving the coverage by the dorsal acetabular rim (or replacing it) — this part of the acetabulum is what supports most of the dog’s weight on the femoral head. If femoral anteversion is around forty-five degrees, a pelvic osteotomy will not be enough to correct for the severe internal rotation of the limb and a femoral osteotomy needs to be done as well. The angle of anteversion that is considered “normal” has not been established, but most believe anything greater than forty degrees is excessive.

An intertrochanteric osteotomy is the cutting of the shaft between the “shoulder” (the greater trochanter) of the femur and the lesser trochanter in order to change the angle at which the femoral head is seated in the acetabulum. A trochanter is a natural elevation or process of bone. The operation gets its name from where the saw cut is made, between the two trochanters on the femur—one “bump” is shoulder-like and the other is located below the femoral head. Another operation that is sometimes performed involves cutting off the greater trochanter and moving it lower on the shaft so that it won’t rub against the acetabulum in its new position. An intertrochanteric osteotomy is also often performed when the pelvis is cut and repositioned. Schrader says, “Caudal transplantation of the trochanter should be avoided because it causes internal rotation of the hip.” By this is meant moving it toward the tail. He also recommended that for best results it not be moved too far down the shaft of the femur, either.

Another procedure to treat HD is to lengthen the femoral neck to seat the head more firmly into the acetabulum. This is a simple approach, but it does not mean that the surgery is simple. According to Slocum and DeVine, a very short neck can contribute to the head falling out of the socket. Results are not promising if the acetabulum has filled with new bone or if the osteoarthritic deposit of bone around the head and cup is too much. Slocum performs femoral neck lengthening if surgery on the pelvis would not correct enough of the laxity, but Smith (Chief of Surgery at the University of Pennsylvania) finds the lengthening procedure to be risky and not proven in efficacy. Pictures of these procedures are found in my orthopedics book.

Triple Pelvic Osteotomy

A triple pelvic osteotomy, TPO, is a tricky but popular reconstructive or salvage procedure among surgeons, in which the pelvis is cut in three locations to rotate the center portion, where the acetabulum is located. Surgical rotation of part of the pelvis on its axis been investigated in man at least since the late 1950s. By 1969 it was being tried in dogs. The first prerequisite is that the dog has enough useful joint surface to offer a deeper fit once the acetabulum has been repositioned to give better coverage of the femoral head. It would do no good if the cartilage or acetabular rim were excessively worn, for} the purpose of this realignment of acetabulum and femoral head is to improve congruity) not rebuild the structure.

Much of the professional literature omits the word “triple” but the procedure is basically the same. To prepare for pelvic osteotomy, the dog is examined to see if it is a good candidate. This includes checking for Ortolani sign, good radiographs, and normal pre-op blood work. A pectinectomy is performed first, then a section of the pubis is removed and reserved for use in making a bone graft for the ilium. Next, an incision is made over the ischiatic tuberosity, and the ischium is exposed and cut. The third cut is made in the ilium, after which a stepped and twisted metal plate is affixed to the bone on both sides of the cut, the amount of twist being determined during the preoperative exam. The reserved piece of pubis is cut up into small bits and used in this area as bone grafts to help strengthen the new structure.

While intertrochanteric and pelvic osteotomies reduce laxity and improve congruity, these must be done early, as soon as laxity and pain are noticed, so that beneficial bone remodeling can occur. This is best accomplished early in life. Most successful pelvic osteotomies are performed on dogs between the ages of six and ten months. One study reported first-year success rates of 68-84%. If the dog is much older, the bones will not heal as fast and the joint is likely to be changed by osteophytes, an eroded acetabular rim, and other changes.

In earlier years, pelvic osteotomies sometimes rotated the acetabular section too far, which allowed the acetabular rim to grate against the femoral neck during movement. Other complications, while not frequent, can still occur: the newly directed compressive forces on the growth plate and epiphysis sometimes result in a necrosis similar in some respects to Legg-Calvé-Perthes disease and in growth disturbances in both the femoral head and neck. Gait abnormalities often persist, though of a different nature than before the surgery, and are usually more noticeable in dogs with very little rear angulation or tarsal hyperextension. Often, patients seemed more stiff legged and straight in the stifle after having a pelvic osteotomy. Mobility may have to be sacrificed, in part, for stability.

Is triple pelvic osteotomy for your dog? Perhaps. TPO has become the next-preferred surgical approach after total hip replacement. Pelvic osteotomy is perhaps more a preventive, rather than a reconstructive or salvage, technique; the benefits of preventing further deterioration have not been fully documented to everyone’s satisfaction. The “catch” is that if owners wait until they see signs of osteoarthritis, it is possible that some dogs may have too much remodeling or osteophyte growth to be ideal candidates for the surgery. Fewer than a third of dogs with “excessive” laxity do not develop osteoarthritis by an average age of 28 months, so that means most affected dogs are probably candidates for some sort of treatment. It may be TPO is right for your young dog. If you have a younger dog, though, perhaps the next, more recent procedure is the best yet.

JUVENILE PELVIC SYMPHYSIODESIS

Late in 2000, another new but less invasive surgical procedure recommended for puppies determined to be at risk for developing DJD was introduced. It is called “juvenile pubic symphysiodesis” (JPS), and currently appears to be optimally performed on pups that are 12 to 20 weeks old. Obviously, such at-risk pups can best be identified during PennHIP evaluation of laxity and early bone changes. Dr. Kyle Matthews of NC State originated the idea, and Drs. Tass Dueland, Allison Patricelli, and Chess Adams, with other members of the University of WI-Madison research team developed the technique in dogs. They all strongly suggest “neutering” (orchidectomy or ovariohysterectomy) be done while the patient is under anesthesia. The pubic portion of the pelvis is between the left and right halves and is toward the lower “front” in standing bipedal animals and on the rear belly side in the dog standing on all fours, where the process of pelvic growth is about the last to occur. A small ventral and approximately midline incision is made, the very short symphysis (analogous to the growth plates you are already familiar with) is cleared of soft tissues, and an electric scalpel is used to cauterize the pubic portion of the pelvic symphysis.

What this operation does is cause premature closure of the medial pubic physes. This junction of the two halves is fibrocartilaginous in the middle with hyaline cartilage to each side, the natural precursor to ossified bone at this age. Since the medial pubic symphysis is hyaline cartilage, which plays a major role in growth of the pubis, a cessation or slowing of growth there allows the continued growth elsewhere to rotate the pelvis and therefore the hip joint. Thus, the acetabula become rotated, a similar effect to that produced by TPO; this results in better coverage of the femoral heads. The Wisconsin experience to date shows, in most cases, that if the surgery is performed at the appropriate age, hip joint laxity improves (is reduced) as shown by Ortolani-positive hips becoming Ortolani-negative, and PennHIP distraction indices improving with time. Collaborative clinical case investigations are underway at Wisconsin, NC State, and other universities by ACVS surgeons.

OTHER SURGERY

The above descriptions do not intend to imply that there are not other approaches. Surgeons are always trying to develop improved techniques. At the 1998 Veterinary Orthopedics Society meeting a technique called “DARthroplasty” was introduced and suggested for a pool of dogs similar to those looked at by Penn and by Barr et al. Based on the data from the more conservative approaches, Smith’s group suggested it be “given ‘investigational’ status until further scientific studies with appropriate controls” could determine the efficacy compared with that of the non-surgical treatments.

BEST APPROACH: CONSERVATIVE MANAGEMENT

A study carried out at Bristol University in the United Kingdom found that, in many cases, conservative management produces good results in treating HD in growing dogs. By this term we mean little or nothing is done other than occasional medicinal relief of pain when called for, but for the most part, no surgery. Since it had long been observed that the gait or limb function in some dogs spontaneously improved as they reached maturity, Barr, Gibbs, and Denny undertook a ten-year study of sixty-eight puppies that had both clinical and radiological signs of HD, using conservative treatment as their guideline. Labrador and Golden Retrievers, German Shepherd Dogs, Saint Bernards, Rottweilers, Collies, a Bloodhound, a Rhodesian Ridgeback, and a Cavalier Toy Spaniel were in the study.

Radiography revealed 73% to have severe HD as evidenced by subluxation and 80% had grade one or two secondary degenerative changes described as “periarticular new bone formation.” Not all dogs lasted the length of the study, but seventy percent were followed; the mean age at follow-up was four and one-half years. Three dogs were destroyed between the ages of ten and twelve months because of continued dysplasia problems, but the information on them was included in the statistical study. Two had pectineal muscle surgery after entering the program and one of these, operated on at twelve months, improved over the next few months in the program. The other was operated on at five years of age when lameness returned after being absent in early-to-mid adulthood (it had had signs as a pup when it entered the program). In this dog, the pectinectomy was disappointing when the dog was reexamined six months postoperatively.

At the time of initial follow-up, nearly half of the study dogs had no hind-limb gait abnormality (observed without being stressed) and 28% had slight or intermittent abnormalities such as a swaying action of the hips. Eighteen percent had moderate abnormalities, and in 6% the problems were considered severe and continuous. When difficulty in getting to their feet from a sitting position was evaluated, 18% had slight problems, 26% had noticeably more trouble, and 56% had no difficulty. Normal exercise amounting to an average of three miles per day was given to 72%, while owners restricted exercise in 28% of the dogs.

About 90% of the nineteen dogs later returned to the veterinary school for clinical and x-ray examination showed either a slight sway or no gait abnormality at all. A couple had obvious lameness and several showed pain when the hips were forced into an extended position beyond what they would do themselves. Several also had crepitus or crepitation, that condition of a grating or grinding noise in the joints which indicates bone or cartilage is scraping instead of sliding noiselessly on a cushion of synovial fluid. About one fifth of the dogs had restricted rear stride and more had some degree of muscle atrophy around the hip joint. Without heavy exercise, 63% showed no discomfort, even when limbs were forcibly extended, and 80% had a normal range of movement. In 72% of the cases, owners reported normal tolerance to exercise.

Some of the radiological findings reported in that study do not totally agree with findings elsewhere, but these researchers felt that as dysplastic dogs matured, the degree of laxity stayed pretty much the same, but osteophyte formation increased most rapidly between six and eighteen months of age, and then not as fast thereafter.

The results of the British study appear, at first, to be startling, but this is because for so many years we have been focusing on surgical treatments, with only lone voices calling for restraint. This emphasis is understandable, for if Rover has pain now, the owner wants his pain relieved now (and for life). In the days before we had much or any knowledge of HD, the disorder was attributed to other causes in the persistent cases, but a great many of the afflicted dogs grew out of the worst symptoms as their skeletons stopped growing and the joints ceased remodeling. The British report on conservative management was, in a way, a return to pre-HD-awareness days.

Spontaneous improvement in hind-limb problems was attributed to healing of the microfractures (which most feel is the primary cause of pain), increased stability through less mobility via remodeling (filling in the joint space with bone deposits), and a thickening of the joint capsule due to prolonged and repeated irritation of the connective tissue. It is possible the adult dog can withstand pain better than the young pup. If 76% of dogs, such as found in this study, can be considered to have acceptable, long-term function of the hind limbs without anything beyond normal care, the owner of a pup with dysplasia should carefully weigh the option of conservative management.

A more recent study report appeared in an abstract entitled “Non-surgical Management of Severe Hip Dysplasia: Long-term Results” and authored by Smith, Fordyce, and Gregor of the U. of PA. It referred to the 1987 Barr, Denny, and Gibbs study in England. The researchers at Penn acknowledged that spontaneous improvement often occurs in maturing dogs, and noted that of the small group studied, 100% of the owners were glad they chose conservative rather than surgical management of their severely dysplastic dogs. Most of the dogs had little or no pain or gait symptoms when re-examined anywhere from 8 months to 6 years after the initial diagnosis of severe HD (laxity, DJD, or both). Most did not restrict the activity of their dogs, and most continued with as-needed administration of pain relief medications.

MEDICATION

The use of medication is included in conservative management in most instances. You might do nothing in the case of the dog with little or no physical symptoms except to let him grow through the most difficult period—those fast-growth months. Most dogs with mild HD are free of outward signs after they reach skeletal maturity (when the physes are ossified and no further growth changes take place in the joints and bone ends) and before they reach an age when the effects of arthritis build to a noticeable level. The effects are highly variable. Some dogs will not show much sign of movement restriction until a couple years or so before their natural lifespan ends; others have earlier degenerative joint symptoms by three to six years of age. If you decide not to use treatment in young dogs, you might also decide to just let the dog “live with” its disability later or, if there is some pain, give him occasional analgesics such as buffered or coated aspirin, some of the newer nonsteroidal anti-inflammatory drugs (NSAIDs), or other medication prescribed by your veterinarian. But remember, every drug has side effects. Use only enough medication to relieve the worst of the pain and give your dog a rest from the effects as often as you and your vet decide. Many NSAIDs, like aspirin, cause bleeding or ulcers in the stomach and small intestine, and have other undesirable effects; they should be used only for short periods of time and in carefully controlled dosages. Many are very slow to be eliminated by the body, and overdose by accumulation can thus be a danger.

Acetaminophen and ibuprofen have become over-the-counter home remedies, but the former has shown to be toxic to dogs (worse for cats) and the latter has its own drawbacks for pets. Some vets prescribe phenylbutazone (“bute”), some meclofenamic acid. The former depresses bone marrow formation, where red blood cells develop and mature. Carprofen (one brand name is Rimadyl™) is a more effective anti-inflammatory agent than aspirin or phenylbutazone, and apparently reduces crepitus, increases stride length formerly restricted by pain, and has less gastro-intestinal irritation. As with any medication, some users blamed it for bad effects, and the popular press and Internet carried many a panic message for a while. This happens so frequently, that wise owners take these scares with a grain of salt. There have been a few cases of liver or other complications, though.

Carprofen is a carboxylic acid related to ibuprofen, ketoprofen, and naproxen—NSAIDs that you may be familiar with from a tour of your own medicine cabinet. They block production of prostaglandins, providing analgesic and anti-inflammatory effects. Side effects are relatively low. At the end of 1998, fellow science writer John Cargill told me about a Rimadyl vs. EtoGesic™ (carprofen vs. etodolac) comparison using force plate analysis. Force plate testing tells you how much weight a dog will put on each limb when standing. Ft. Dodge, a pharmaceuticals company that most dog owners are familiar with because of their vaccines, states that Rimadyl had no statistically significant improvement in weight-bearing ability vs. controls. In their 1998 brochure, EtoGesic shows a 5 times greater-than-control improvement in vertical impulse area and a 4 times improvement over controls in vertical peak force. Nagging reports of numerous fatalities linked to adverse reactions to Rimadyl have peppered the Internet discussion lists.

Most medications you are familiar with rely on reduction of inflammation, and the above are examples. Corticosteroids are in a class of one of the most over-prescribed medicines that human and animal doctors shove down throats or into bloodstreams, the other being the antibiotics. In both cases, it is often a defensive technique, like the M.D. who takes a lot of radiographs more to “cover his tail” in case of litigation than to find out anything more than he can with a simpler exam and questions. Steroids such as methylprednisolone, prednisone and dexamethasone mimic naturally-generated body chemicals such as cortisone and adrenaline; most have serious side-effects such as suppression of the immune system, depression of the adrenal glands’ function, stomach ulcers, capillary rupture and bleeding just under the skin, other cardiovascular problems, skin becoming brittle, and increases in appetite and thirst. Doctors Peltier and McIlwraith have also suggested that corticosteroids can inhibit proteoglycan synthesis and thus disrupt the cartridge matrix in articulating joints. Proteoglycan is necessary to provide stiffness and other properties to the matrix. The conclusion is that steroids are not appropriate for long-term management, although they may be needed for a short time in the acute stage of many complaints including HD. I once had a bitch that required a shot of prednisone every 28 days or so, otherwise her atopic-allergy-initiated scratching and chewing would become intolerable. She also developed heavy phlegm which she tried to combat by eating anything “scratchy” such as sand, dried pine needles, debris, and even the part of the fiber-glass curtains hidden from our view, behind the couch! I am sure the steroids contributed to her mesenteric bleeding many years later after an operation for gastric torsion, and her death a few months later.

DMSO, dimethyl sulfoxide, is a chemical with many uses. It has a long history as an industrial solvent, and almost as long as a “horse liniment,” giving warm relief to aching muscles and joints. For years it was a “hot seller” in all sorts of stores for human use in treating similar pain, and had a relatively short period of use in treatment of dogs’ aches in hip and other joints and muscles. One big risk is that it is such a potent solvent, that it apparently dissolves and carries through the otherwise-protective skin barrier and into the bloodstream, many microorganisms existing on the surface.

One fairly recent development in drug therapy is polysulfated glycosaminoglycan (PSGAG, one name is Adequan™), a “natural” compound already in use in equine practice. PSGAG was developed mainly for use in the horse, but in 1987 an article in a professional journal introduced Adequan to the veterinary community as an experimental drug for dogs and the news quickly spread through part of the dog breeding community as well. It is almost a duplicate of the GAGs naturally produced by the canine body along with vitamin C. Six weekly injections are supposedly sufficient, in most cases to relieve much of the symptoms of HD (lameness, Ortolani’s sign, etc.) for an undetermined length of time.

The drug is chemically very similar to the mucopolysaccharides of cartilaginous tissue, which has been described earlier. In fact, many have now substituted the word glycosaminoglycan for the word mucopolysaccharide. Dr. Joe Alexander, dean of the veterinary­ school at Oklahoma State University, describes it as “a potent proteolytic enzyme inhibitor [which] diminishes or reverses the processes which result in the loss of cartilaginous mucopolysaccharides.” These processes he speaks of include the synthesis of prostaglandins and interleukins; the drug may also inhibit the release of, and aid in the scavenging of, free radicals (damaging ions) as well as inhibit the effects of lysosomal (body-cell?dissolving) enzymes. Apparently, it stimulates synthesis of sodium hyaluronate or hyaluronic acid, which with glycosaminoglycan is the main component of the synovial membrane’s boundary lubricant; it lowers synovial protein level, and increases the viscosity of the synovial fluid much like oil additives are supposed to protect your car’s engine. Some researchers believe that it slows or even inhibits secondary (arthritic) degeneration that accompanies HD. The drug apparently also inhibits white blood cell (neutrophil) activity and the action of “complement,” which is part of the immune response collection of macromolecules and chemicals.

One idea is that it stimulates chondroblast (cartilage-producing cells) activity and synovial fluid production. Stepped up production of cartilage may or may not rebuild some abraded or eburnated, worn-thin connective tissue in the joints. While increased synovial fluid may on the surface seem to be at odds with Smith’s hypothesis that excess synovial fluid pressure is a prelude to HD, it may be that once a joint is deformed by HD, it needs that extra lubricant.

Time will tell whether PSGAG can be used safely in place of painkillers such as aspirin, which only cover up some of the discomfort but do nothing in regard to repairing or protecting the cartilage. Except for some pain response apparently related to cold weather, Adequan is promoted as being free of unwanted side effects, with a possible reason given that since it occurs in the body, any excess is metabolized or excreted. However, there is a possibility that dogs with frank or subclinical von Willebrand’s Disease or hemophilia, who are on “blood thinners” or who have infections might be poor candidates for injectable PSGAG treatment.

Adequan is currently being used with variable success, appearing to ease discomfort in a number of joints. Currently, it appears that some dogs tend to build tolerance to PSGAG, so the beneficial effects may decrease over a period of time. Perhaps by the time you read this, some long?term studies will have been completed that would lend more confidence to Adequan’s current promise.

In the early 1990s, a cooperative study by Cornell, the Universities of Pennsylvania and North Carolina, the Ralston Purina Company, and a Swedish pathology lab indicated that the development of HD could be suppressed somewhat by altering the concentrates of positively-charged electrolytes in the diet and hence in the synovial fluid. It was recommended to decrease meat and bone meal with their high sodium and potassium levels, and partially substitute more rice and corn gluten meal to boost the chloride level. Still more work is needed to develop data. If corn meal or corn oil (or other vegetable oils) are used in greater amounts, I recommend supplementation with Vitamin E, regardless of health condition.

NUTRITION OR MEDICATION?

There are several products on the market, some called “nutraceuticals” because of their hybrid drug/nutrient activity; examples are Glyco-Flex™ and Cosequin™, which are being touted as beneficial to the dog with HD, supposedly by improving the lubricity in the joints. The former is a preparation from the green-lipped mussel, brewer’s yeast, and alfalfa; it provides protein, GAGs, amino acids, chelated minerals, vitamins, and enzymes. The latter is glucosamine, chondroitin sulfate, and manganese ascorbate (a combination of vitamin C and the mineral). Glucosamine may be more effective if given by injection rather than orally (enterally), but I am living, walking (running) proof that oral use really works “miracles.” The reported difference between oral and injected versions also seems to be true of some vitamins, such as B and A. But most people and their dogs find all the benefits they want, by ingesting them.

Because of old injuries and arthritis in my knees, and a favorable article in Consumers Reports, I tried an initial 6-months’ regimen of glucosamine alone, and after the first 5 or 6 weeks, I was pain-free and except for very infrequent minor twinges, have been completely “cured” of the symptoms. Previously, I could not sleep for the discomfort, and had frequent, sometimes continuous pain. I have been on it for many years now, and can run and bike my dogs, handle dogs at the demanding German-style shows, climb my mountains, carry loads, etc. Some others have seen the same near-miracle in their dogs. Anecdotal testimonials vary from enthusiasm to the statement that the dog no longer responds to them as it first appeared to. You can probably get all the relief you need, as I did, with the cheapest brand of straight glucosamine (no other ingredients needed) from a discount drug store or superstore market.

Shark cartilage and similar health-food approaches have no proven benefit yet, and feeding chicken necks/wings/joints may please your dog’s palate, but while they may contribute to a glossy coat and other healthy appearance, it does not have any real, verifiable value in regard to relieving joint discomfort; some say that the lubricating macromolecules in such dietary cartilage do indeed remain un-metabolized and thus reach the sites where needed. For further reading on the proven products above, read the bibliographic references given by Dog World (USA) writer, John Cargill, if you can find them. (DW, October 1995, p. 28).

NUTRITION AND ITS ROLE IN TREATMENT

Even among those who attempt to use and follow precepts of science and logic, there will be emotion-based decisions and courses of action. Take for example ideas relating to canine hip joint integrity. Only a few ostrich-brained relics are still sticking their heads in the sands of ignorance and avoidance, claiming HD to be simply or mostly an environmental problem. Even among the ranks of the cognoscenti, however, there are those who hang onto the hope of a “magic pill” approach. Vitamin C or seaweed or anything else that comes along with the false promise of an easy, mystical or non-understandable (or rationalized) way out of the suffering that severe HD can bring—any of these approaches are emotional roads purported to lead to the goal of better dogs. But their proponents have unintentionally or ignorantly twisted the road signs to make you think they are accurately pointing to the same destination. Only the hardcore of those who want the easy ways out are today avoiding the logical, science-supported fact that HD is essentially a genetic disorder and can only be finally dealt with by selecting breeding partners. You can sometimes ease the life of one afflicted by modifying the environment through nutrition, bedding, temperature, etc., but you cannot change the genes.

Since nutrition is a subject with many myths and opinions, I perhaps should skirt it or treat it in a separate article. But since it apparently has some therapeutic nature, it should be mentioned here, too. It is thought that Vitamin E not only works synergistically with C to combat stress, but even more, helps the body to get rid of metabolic and neuro-synapse waste products and thus reduce pain. The value of vitamin E in relief of pain and the support of general well-being has been fairly well researched. It is not only an intracellular antioxidant, but it also has other functions, including metabolism of arachidonic acid, which is a precursor to prostaglandins, which play an extremely important role in pain management. In this respect, it and other antioxidant vitamins do something similar to what the steroidal drugs do: inhibit prostaglandins and cyclo-oxygenase in the “arachidonic cascade.” An article in the journal VetMed many years ago gave evidence of its use, synergistically with adequate (small [trace] amounts) of selenium, in alleviating HD and other joint pain.

The best application of a nutritional approach to treatment of HD is very simple: get the weight off. Excess weight and stress from activity make the dysplastic joint deform and wear faster. To allow the dog’s cartilage to change to bone before the joint would tend to deform with overnutrition and work, keeping the dog slim will be the kindest deed you can offer your dysplastic pet. Overfeeding truly can be “killing with kindness,” which really is not kind, but cruel.

Fred Lanting

Fred Lanting is an internationally respected show judge, approved by many registries as an all-breed judge, has judged numerous countries’ Sieger Shows and Landesgruppen events, and has many years experience as one of only two SV breed judges in the US. He presents seminars and consults worldwide on such topics as Gait-&-Structure, HD and Other Orthopedic Disorders, and The GSD. He conducts annual non-profit sightseeing tours of Europe, centered on the Sieger Show (biggest breed show in the world) and BSP.

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