Canine and Feline Hip Dysplasia: Causes, Treatment and Prevention
One of the most common diagnoses that creates great cause for alarm among many pet owners is hip dysplasia.
Fortunately, having your dog or cat diagnosed with the condition does not mean a death sentence. Instead, owners of hip dysplasia-affected pets should consider the option for surgical correction and must implement a series of lifestyle modifications in attempt to reduce stress on the hips that inevitably causes joint surface damage, pain, compromised mobility, and other health issues that negatively affect overall quality of life.
What is Canine and Feline Hip Dysplasia?
Dysplasia is a health condition where a developmental abnormality exists that prevents normal functioning of a body part or organ system.
With hip dysplasia, the hip joint improperly forms and ultimately leads to arthritis. Arthritis (from arthro- meaning joint and -itis meaning “inflammation of”) is joint inflammation, which can have many underlying contributing factors, including abnormal joint confirmation, infection, cancer, immune-mediated disease and others. If arthritis goes unresolved or becomes chronic or recurrent then joint surfaces become irregular and limit a pet’s comfort, range of motion, ability to eliminate, and other functional aspects of day-to-day existence.
To best comprehend an ailment like hip dysplasia it’s important to understand the normal anatomy of the hip joint, which is considered a ball and socket joint. The shape of the joint is basically as it sounds where an object that appears rounded (i.e ball) fits into a recess (i.e. socket). In the case of the hip, the ball is the femoral head (upper/inner-most part of the thigh bone) and the socket is the acetabulum (scooped-out area in the pelvis). The ball and socket conformation permits the hip joint to have extensive range of motion, such as flexion, extension, adduction (to bring closer to midline) and abduction (to take away from midline).
Other joints like the shoulder also have a ball and socket conformation. The elbow and knee are considered hinge joints, as they function like the hinge of a door and lack the extensive range of motion of the ball and socket joint being limited to flexion and extension.
What Are the Causes of Canine and Feline Hip Dysplasia?
While the causes of hip dysplasia or are not fully known, there are many contributing factors including genetics, activity, lifestyle, weight, nutrition, and others.
Hip dysplasia is a developmental disease, which means it occurs at some point as a pet matures from puppy or kitten life stages into an adult.
Hip dysplasia has a strong genetic component, so when one dog has hip dysplasia there’s potential the condition can be inherited by future generations. In both dogs and cats the genetic aspects of inheritance are complicated to the degree that even if both parents have normal hips their offspring can develop hip dysplasia.
Certain dog breeds are known to have hip dysplasia, including the Bernese and Swiss Mountain Dog, German Shepherd, Golden and Labrador Retriever, Great Dane, Mastiff, Rottweiler, Saint Bernard, Weimaraner, and others. Mixes of these breeds can also potentially develop hip dysplasia.
Cats can also be affected by hip dysplasia, but they tend to show subtler clinical signs and are generally less-commonly diagnosed with the condition than dogs. Breeds like the Himalayan, Maine Coon, Persian, and others are more susceptible than mixed-breed cats. Female, purebred cats are more prone to hip dysplasia than males.
There is a stronger correlation between a pet’s size and the tendency to be affected by hip dysplasia. Generally, large cats and large to giant sized dogs (irrespective of being pure or mixed breed) are more prone to developing hip dysplasia than small and medium-sized pets.
There also is a potential correlation to trauma and day to day wear and tear contributing to hip dysplasia. If a pet severely slips or falls or incurs some form of significant trauma on a single or repeated basis the head of the femur may not stay in the hip socket as well and can partially or fully shift (luxate) off the articulating surface of the acetabulum.
How is Hip Dysplasia Diagnosed in Canines and Felines?
A pet’s display of clinical signs of hip dysplasia commonly leads to the condition’s diagnosis. Clues about a pet being affected by hip dysplasia can also emerge during a veterinarian’s physical examination. Diagnostic testing is the best means of diagnosing the condition.
Clinical signs of hip dysplasia can occur any time in a pet’s life, but many affected pets show signs early in life during the juvenile or young-adult life stage. In dogs, hip dysplasia is commonly diagnosed between six and 18 months of age as the dog develops from puppyhood into adulthood.
There are many clinical signs associated with hip dysplasia, including:
Mobility and stance abnormalities – Reduced weight bearing occurs in one or both hind limbs affected by hip dysplasia, which can also make the pet appear less-able to walk, run, jump, play, stand up, lie down, and more. A “bunny hopping” gait is common among dogs affected by hip dysplasia as using the two hind limbs together while moving distributes weight across the pelvis more-evenly than using the right and left hind limbs independently and can relieve some of the discomfort experienced by weight bearing. Going up stairs, inclines, and onto elevated surfaces becomes a challenge, so a pet may choose to remain on the ground floor of one’s home or show reduced ability to ascend stairs and get up onto the couch or bed or into the car.
Additionally, reduced distance can be seen between the two hind feet while standing. Hip-dysplasia affected pets generally spend more time lying down, show increased circling behavior going from standing to sitting, and struggle to stand from sitting or lying down (and vice versa). It may also be more challenging for affected pets to posture normally while evacuating urine and feces, so waste elimination patterns may be altered.
Pain and behavior changes – When hip dysplasia is present for months to years the hip joint becomes swollen (arthritis), the surface loses its smooth consistency (osteoarthritis, also known as degenerative joint disease or DJD), and pain is experienced. Painful pets can vocalize (upon movement or anytime), have a decreased appetite, act lethargic, resist being touched, spend more time in isolation than being around other pets or people, and show aggressive behaviors (growling, barking, biting, etc.).
Muscular/bodily alterations – Since hip dysplasia is a problem of the hind limbs an affected pet tends to overcompensate while moving by primarily using the front limbs. Subsequently, the shoulders become more muscularly developed, the mid-upper back muscle can overexert and spasm, and the hind limbs may show signs of muscle loss (atrophy).
Physical exam anomalies – When pets affected by hip dysplasia are examined by a veterinarian there are multiple physical exam findings that may deviate from the norm in addition to those observations mentioned above. Early on in the disease process the hip joint can feel loose upon range of motion as a result of the head of the femur not having a snug fit inside the acetabulum. A popping sound and sensation called the Ortolani sign may be present with a dysplastic hip.
Once osteoarthritis sets in over months to years of living with hip dysplasia, lack of normal range of motion is seen as reduced flexion, extension, adduction, and abduction and is seen, felt, and can be measured with a tool called a goniometer.
Radiographic (x-ray) changes – Over time arthritis becomes osteoarthritis, where joint surface changes are present and can be visualized on radiographs (x-rays).
The Orthopedic Foundation for Animals (OFA) can review hip radiographs of dogs aged two years or greater to give a grade of one of seven categories: “Excellent, Good, Fair (all within Normal limits), Borderline, and then Mild, Moderate, or Severe (the last three considered Dysplastic).” Dogs having Excellent or Good hips at two years of age and their offspring may not always have normal hips due to the aging process and lifestyle factors.
Other radiograph scoring systems like the FCI (Fédération Cynologique Internationale), the OFA, the BVA/KC (British Veterinary Association/The Kennel Club), and PennHIP are also available.
PennHIP is a technique of measuring hip laxity using a special tool (distractor) to enable the hip to be visualized via radiographs in multiple positions (compressed, distracted, extended) to calculate a numeric Distraction Index (DI) index that correlates with a tight or loose (dysplastic) hip joint. DI “as determined by the PennHIP method is the most reliable indicator of future hip osteoarthritis.” The patient’s muscles must be completely relaxed to permit Penn Hip measurements, so deep sedation or general anesthesia must to used. Dogs as young as four months of age (16 weeks) can evaluated via PennHIP.
Advanced imaging techniques – Although not as common as radiographs, advanced imaging techniques like computer tomography (CT scan) and magnetic resonance imaging (MRI) can potentially be used to diagnose patients having hip dysplasia and the progression to osteoarthritis. CT is more reliable for cavities, bones, and joints, while MRI is better to image the brain, intervertebral discs, spinal cord, and nerves. Both CT and MRI require general anesthesia using inhalant gas.
How is Hip Dysplasia Treated in Dogs and Cats?
Fortunately, there are many options when it comes to treating hip dysplasia and the inevitable progression to osteoarthritis.
The only curative treatment for hip dysplasia is surgery. The good news for our pets is that multiple techniques can be used to surgically repair a dysplastic hip. The bad news with surgery is the considerable financial expense, months of recovery time, and significant physical and emotional involvement by pet owners for the post-surgical process to be successful. Potential for complications in healing exist if all recommendations made by the veterinary surgeon are not followed. The most-common three surgical options include:
Femoral Head Ostectomy (FHO) – The FHO procedures involve cutting off the head of the femur (ostectomy= to cut into bone) so that the hip is no longer a ball and socket joint. A false joint forms where the muscles that hold the femur in position adjacent to the acetabulum do the work in maintaining some semblance of normal conformation and there is no longer any bone-on-bone contact causing inflammation and pain. This procedure is more common for dogs that are 50 pounds or pets having experienced traumatic hip dislocation that fails to be corrected with an Ehmer (Figure-8) sling and activity restriction.
Triple Pelvic Ostectomy (TPO) – In the TPO the pelvis is cut in three sites to reconfigure the confirmation of the hip so that the acetabulum provides improved coverage over the femoral head. A benefit of performing TPO on one hip is that doing so may relieve enough weight-bearing burden from the other hip and a second procedure on the other side may not be needed. A limiting aspect of TPO is that it must be performed on patients that have not yet developed osteoarthritis, so dogs that are less than 12 months of age are generally the best candidates for successful outcomes.
Total Hip Replacement – The Total Hip Replacement does what its name implies in giving your pet a prosthetic hip joint made from metal and injection-molded plastic. This procedure is most-ideal for dogs that have hip dysplasia and already have radiographic signs of osteoarthritis.
Hip surgery is best done by a board-certified veterinary surgeon, but some general practitioners having a strong interest in surgery and more seasoned veterinarians who have practiced in the years before specialty veterinarians were available may have the skills and experience. You can locate a Diplomate of the American College of Veterinary Surgeon (DACVS) in your area via www.acvs.org or through your primary veterinarian’s referral.
Non-surgical treatments for hip dysplasia involve management of the inflammation and pain resulting from abnormally-formed hips. There are many treatments available that can minimize inflammation, numb pain, improve range of motion, and promote blood flow to affected joints.
Anti-inflammatory and pain-numbing medications – Osteoarthritis is a disease resulting from joint inflammation, so the use of prescription non-steroidal anti-inflammatory medications (NSAIDs) is common practice for dogs and cats suffering from hip dysplasia associated pain.
Although NSAIDs effectively reduce joint inflammation, mild to severe side effects are associated with their use especially on a prolonged basis or at higher doses. The digestive tract, kidneys, liver, red blood cells, platelets, nerves and other body tissues can be adversely affected.
Drugs having a more pain-numbing effect like opiates (Tramadol, Buprenorphine, Amantadine, etc.) and GABA-analoges (Gabapentin) can help hip dysplasia patients exhibiting pain and can reduce NSAID dose and frequency of administration. Yet, pain-numbing drugs also have potential side effects like sedation, reduced appetite, slowed digestive tract movement, and others.
I strongly advocate for the multimodal approach in managing the pain experienced by my patients having hip dysplasia. Multimodal means that more than one type of treatment modality is used to address an ailment so whole-body health is prioritized and smaller or less- frequent doses of drugs potentially having side effects are needed. Besides NSAIDs and pain-numbing medications, the multi-modal approach to pain includes:
Joint supporting nutraceuticals – Nutraceuticals are substances derived from food having medicinal effects. Chondroprotectants (i.e. cartilage protectors) are nutraceuticals that promote joint health and include glucosamine, chondroitin, MSM, vitamins (C, E, etc.), minerals (Calcium, Manganese, etc.), antioxidants (Selenium, Alpha Lipoic Acid, etc.), anti-inflammatory substances found in plants (turmeric, phycocyanin, etc.) or animals (fish oil derived omega fatty acids, etc.) and more. Such products generally need to be taken every day to be effective.
Cartilage rebuilding medications – Besides nutraceuticals, injectable medications that benefit joint health and rebuild cartilage are available, including Polysulfated Glycosaminoglycan (PSGAG, like Adequan), Sodium Pentosyn Sulfate (Cartrophen), and others. Besides having more proof of their beneficial effects, injectable chondroprotectant medications travel via the bloodstream from the injection site to multiple joints instead of needing to be absorbed from digestive tract to then enter the blood to reach the joints and are therefore great for patients that already have digestive problems or take medications compromising digestive tract health. Additionally, the dosing frequency injectable chondroprotectants is often maintained at a frequency of every seven to 30 days pending the patient’s needs.
Environmental and lifestyle modification – A pet’s environment and lifestyle must be modified so that less stress is put on joints affected by hip dysplasia and the potential for injury is reduced. Lowering the height of a bed or couch and using a step, stairs, or ramp next to the bed, couch, or other elevated surfaces generally provides safer passage. Carpeting, runner rugs, and yoga mats and foot and nail covers (Pawz, ToeGrips, etc.) can improve traction on slick floors. Access points to stairs can be blocked by gates to prevent pets from injury incurred during ascending or descending. Access to the backseat or hatchback of cars is safe using ramps, stairs, slings, or other devices.
High-impact activities like running, ball playing, etc. are high-impact and should be modified to lower-impact exercises like walking, hiking, swimming, and physical rehabilitation.
Cats access to elevated surfaces like counters should be restricted and the height of the litter box edges must be lowered to allow simpler access.
Weight management – Overweight pets having hip dysplasia are more prone to suffering from arthritis pain, so keeping your pet slim on a life-long basis is crucial.
The 2007 Imperial College of London Study Dogs Lived 1.8 Years Longer On Low Calorie Diet: Gut Flora May Explain It revealed the health benefits associated with consuming fewer calories. The study’s canine participants consumed 25% fewer calories than their non-calorically restricted counterparts, lived 1.8 years longer, were less prone to developing osteoarthritis and other obesity-related ailments, and had an older median age for onset of later-life diseases.
I recommend owners always restrict their pet’s daily calories and maintain a slim body condition score (BCS) on a lifelong basis. As part of a routine wellness examination, your veterinarian can calculate the daily caloric requirement for your pet and recommend a volume of commercially-available or home-prepared food to promote optimal weight.
Generally, my patients eating whole food diets like Honest Kitchen in volumes that meet their caloric needs for ideal body weight have healthier and slimmer bodies and are less-prone to arthritis pain.
Complementary and Alternative Medicine (CAM) – A variety of complementary and alternative medicine (CAM) techniques are available to help patients suffering from pain related to hip dysplasia, including:
- Acupuncture – Insertion of needles into acupuncture points to promote the release of the body’s own pain-relieving and anti-inflammatory hormones. Manual pressure (acupressure), heat (moxibustion), electricity (electrostimulation), injection of liquids (aquapuncture), or laser can also be used to stimulate acupuncture points.
- Herbs – Plant-derived products can help promote blood flow and reduce inflammation in the joints and other body tissues. I prescribe veterinary-specific, U.S.-made products like those made by Xie’s Jing Tang Herbal, Standard Process, and others.
- Laser – Low power (“cold”) lasers can be used to painlessly promote tissue repair, blood flow, oxygen and nutrient delivery, and the removal of metabolic wastes.
- Pulsed Electromagnetic Frequency (PEMF) – PEMF is a non-invasive method of modulating OA pain that owners can even do themselves at home.
- Physical Rehabilitation – Veterinarians and human physical therapists provide physical rehabilitation to animals. Besides the aforementioned modalities, pets can walk on an above-ground or underwater treadmill, swim in a pool, undergo stretching and massage, receive passive range of motion (ROM) therapy, and more. I strive to get owners involved in the rehab process by learning techniques to be performed at home so less-frequent trips to a physical rehabilitation are needed.
Can Canine and Feline Hip Dysplasia be Prevented?
It’s always a challenge to try to prevent conditions like hip dysplasia, yet there are practices that can contribute to a pet having healthier hips on short-term and lifelong basis.
Pets having hip dysphasia should be excluded from the breeding pool. If you suspect or know that your pet has hip dysplasia based on a veterinarian’s examination or diagnostic testing (radiographs) then his or her genetics should not be passed on to future generations.
If you are interested in breeding your pet, schedule a wellness examination with a veterinarian to determine if doing so is an appropriate idea from the perspective of health for your pet and the puppies or kittens. For dogs, arranging for radiographs using PennHIP technique is my top recommendation. Cats can still have sedated or anesthetized radiographs to evaluate hips and a veterinary radiologist can always give an official interpretation beyond that given by a general practice veterinarian.
Owners can minimize the potential for arthritis to occur in all pets, especially those having hip dysplasia, by employing calorie control and promoting a slim body condition on a lifelong basis. Although promoting your pet to lose weight is a great wellness plan, the damage done to joint surfaces and other body parts by carrying excess body mass can be irreversible. Additionally, starting daily oral supplementation with omega fatty acids and chondroprotective supplements or medication early in life can reduce arthritis pain caused by hip dysplasia.
Has your pet been diagnosed with hip dysplasia? Feel free to share your story in the comments section.