Hypertrophic Osteopathy

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Article Written by Dr. Daniel A. Degner, Board-certified Veterinary Surgeon (DACVS)

Animal Surgical Center of Michigan

5045 Miller Road

Flint, MI 48507


Phone: 810-671-0088

Key Points

Hypertrophic osteopathy is usually associated with a primary disease located within the abdomen or chest

Treatment of the primary problem will result in resolution of the bone thickening and pain

The prognosis is highly dependant on the inciting cause of hypertrophic osteopathy


  • Hypertrophic osteopathy is a condition that results in new bone formation (periosteal proliferation) on the bones of the limbs of an afflicted patient. Early in the course of HO, periosteal new bone production starts on the bones of the digits and paw bones and with time continues up the limb.
  • Typically there is an underlying condition that is associated with this condition such as
    • disease in the chest such as a rib tumor, primary lung tumor, metastatic lung tumor, rib tumor, lung abscess, parasite infection associated sarcoma of the esophagus, patent ductus arteriosus, congenital megaesophagus, infective endocarditis (infection of the heart valve), mycobacterial pneumonia, and bronchial foreign body with lobar pneumonia.
    • disease in the abdomen such as kidney tumors, prostatic tumors and other masses within the abdomen
  • The mechanism of formation of new bone on the limbs is not known, however, a disruption in the nerve signals results in a change in the blood supply of the covering of the bones (periosteum) that causes new bone to form on the surfaces of the bones.
  • Resolution of the problem is typically seen once the underlying cause is removed (example: remove the primary tumor and the periosteal proliferation and lameness resolves)

Clinical signs

  • Thickening of the limbs (see photos below)
  • Lameness
  • Pain upon palpation of the extremities
  • Signs associated with the underlying problem such as coughing, weight loss, blood in the urine, loss of appetite



  • The diagnosis of HO is made on finding the classic periosteal new bone production on the bones.
  • A search for another tumor should always be done which includes chest radiographs, abdominal radiographs and ultrasound of the abdominal and visible structures in the chest.
  • Your veterinarian may recommend a biopsy if a tumor is found in the chest or abdomen
  • Blood work such as a CBC and chemistry, along with urine testing will also be recommended if your pet is going to have treatment of the condition (surgical removal of the primary tumor).
  • The radiographs below demonstrate periosteal proliferation of the bones. The final radiograph, which is of the chest, demonstrates multiple lung tumors due to spread of tumor from the urinary bladder.




  • Treatment is only possible if the pet has an operable tumor
  • By removing the tumor the periosteal proliferation will resolve and your pet will be relieved of the bone pain.


  • If the primary tumor can be removed and has not spread, the prognosis is excellent, however if the tumor of primary inciting condition is not treatable, the prognosis is very poor.


  1. Mylonakis ME, Rallis T, Koutinas AF. Canine spirocercosis. Compend Contin Educ Vet. 2008 Feb;30(2):111-6.
  2. Grillo TP, Brandão CV, Mamprim MJ, de Jesus CM, Santos TC, Minto BW. Hypertrophic osteopathy associated with renal pelvis transitional cell carcinoma in a dog. Can Vet J. 2007 Jul;48(7):745-7.
  3. Chiang YC, Liu CH, Ho SY, Lin CT, Yeh LS. Hypertrophic osteopathy associated with disseminated metastases of renal cell carcinoma in the dog: a case report. J Vet Med Sci. 2007 Feb;69(2):209-12.
  4. Dunn ME, Blond L, Letard D, DiFruscia R.   Hypertrophic osteopathy associated with infective endocarditis in an adult boxer dog.  J Small Anim Pract. 2007 Feb;48(2):99-103.
  5. Foster WK, Armstrong JA. Hypertrophic osteopathy associated with pulmonary Eikenella corrodens infection in a dog. J Am Vet Med Assoc. 2006 May 1;228(9):1366-9.
  6. Anderson TP, Walker MC, Goring RL. Cardiogenic hypertrophic osteopathy in a dog with a right-to-left shunting patent ductus arteriosus. J Am Vet Med Assoc. 2004 May 1;224(9):1464-6, 1453.
  7. Watrous BJ, Blumenfeld B.  Congenital megaesophagus with hypertrophic osteopathy in a 6-year-old dog.  Vet Radiol Ultrasound. 2002 Nov-Dec;43(6):545-9.
  8. Harrus S, Waner T, Aizenberg, Safra N, Mosenco A, Radoshitsky M, Bark H.  Development of hypertrophic osteodystrophy and antibody response in a litter of vaccinated Weimaraner puppies. J Small Anim Pract. 2002 Jan;43(1):27-31.
  9. Peeters D, Clercx C, Thiry A, Hamaide A, Snaps F, Henroteaux M, Ogilvie GK, Day MJ. Resolution of paraneoplastic leukocytosis and hypertrophic osteopathy after resection of a renal transitional cell carcinoma producing granulocyte-macrophage colony-stimulating factor in a young Bull Terrier.  J Vet Intern Med. 2001 Jul-Aug;15(4):407-11.
  10. Barrand KR, Scudamore CL. Canine hypertrophic osteoarthropathy associated with a malignant Sertoli cell tumour. J Small Anim Pract. 2001 Mar;42(3):143-5.
  11. Miller C. Hypertrophic osteodystrophy in a Great Dane puppy. Can Vet J. 2001 Jan;42(1):63-6.
  12. Wylie KB, Lewis DD, Pechman RD, Cho DY, Roy A. Hypertrophic osteopathy associated with Mycobacterium fortuitum pneumonia in a dog.  J Am Vet Med Assoc. 1993 Jun 15;202(12):1986-8.
  13. Hesselink JW, van den Tweel JG. Hypertrophic osteopathy in a dog with a chronic lung abscess.  J Am Vet Med Assoc. 1990 Mar 1;196(5):760-2.
  14. Caywood DD, Kramek BA, Feeney DA, Johnston GR. Hypertrophic osteopathy associated with a bronchial foreign body and lobar pneumonia in a dog.  J Am Vet Med Assoc. 1985 Apr 1;186(7):698-700.

Frequently Asked Questions After Surgery

When should my dog have the first bowel movement after surgery?

  • Many dogs will not have a bowel movement for the first 4 to 5 days after surgery
  • Reasons that a dog will not have regular bowel movements after surgery include:
    • The dog has been fasted prior to surgery
    • Dogs do not eat well during the hospital stay
    • They frequently do not eat well when they go home
    • They are fed highly digestible food that produces little stool
    • Pain medication that contain narcotics (such as morphine, fentanyl patches, and tramadol) can be constipating
  • If a pet does not have a bowel movement on the 5th day of being home, a stool softener such as metamucil can be fed
    • Dose of metamucil is 1 tsp per 25 Kg mixed in with each meal (canned dog food); feed immediately after mixing, as the metamucil will gel the food and may make it less palatable

My pet had surgery and will not eat.  What can be done?

  • Dogs
    • Most pets will not eat their regular dog food after surgery, especially if it is kibble.
    • Offer a cooked diet having a 1:1 ratio of a protein source and carbohydrate source.  The protein source can be any meat (example: chicken breast, turkey breast, lean hamburger) that is low in fat and should be cooked (drain off all fat after the meat has been cooked).   The carbohydrate can be pasta, potato or white rice.
    • Try canned dog food; to enhance the flavor sprinkle a very small amount of garlic powder or chicken or beef broth (Chicken-in-a- MugTM or Beef-in-a-MugTM products)
    • Try Gerber strained meats for babies such as the chicken, beef, turkey, or veal
    • Try Hill's A/D diet available at most veterinary hospitals
    • Hand feeding: place a small amount of food in the mouth so that your dog gets the flavor
    • Warm the food slightly in a microwave, as the food will be more aromatic; stir the food before feeding and test the temperature on the bottom side of your wrist; it should only be luke warm.
    • Remember that most pets will not eat the first day or two after they get home from surgery
  • Cats
    • Offer smelly foods that contain fish such as tuna or smelly cat foods
    • Try Gerber strained meats for babies such as the chicken, beef, turkey or veal
    • Hand feeding:  with your finger place a small amount of food on the roof of your cat's mouth; use a syringe to get soft food into the mouth
    • Warm the food slightly in a microwave as the food will be more aromatic; remember to stir the food before feeding and test the temperature; it should be only luke-warm
    • Some cats will only eat dry food, try kibble if your cat normally has been fed that food
    • Petting and stroking your cat frequently will help to stimulate appetite
    • Remember that most pets will not eat the first day or two after they get home from surgery
    • Appetite stimulants such as cyproheptadine may be helpful
    • If your cat refuses to eat anything for 7 days a stomach tube or nasogastric tube should be placed to provide nutrition so that a serious liver problem (hepatic lipidosis) does not develop

My pet is vomiting.  What can be done?

  • The first thing for you to discern is whether your pet is vomiting or regurgitating.  Both will result in fluid or food being brought up.  Vomiting always will have heaving or retching of the abdomen prior to expulsion of the vomitus.  Regurgitation is not associated with heaving and the pet usually just opens the mouth and fluid or food will be expelled.  Usually the regurgited material will be clear or brown colored fluid. 
  • Next is to identify the cause of the vomiting or regurgitation.
  • Causes and treatment of vomiting after surgery
    • When some pets return home after a stay in the hospital they may drink excessive amounts of water at one time and then vomit; if this appears to be the case, the water should be limited to frequent smaller amounts.
    • Medications such as antibiotics, narcotics or nonsteroidal anti-inflammatory medication commonly cause vomiting after surgery.  In order to see which medication is causing the problem, the administration of each drug should be separated 2 hours apart.  Usually the pet will vomit or appear nauseated (drooling and sick look) within 1 hour of administration of the medication that they are sensitive to.  The antibiotic in some cases may be changed to a different one, or may be discontinued. 
    • Stomach upset from anesthesia is a potential cause of vomiting and will pass within a couple of days. 
    • An uncommon cause of vomiting after surgery is internal organ failure.  Blood testing will confirm this problem. For this reason vomiting should not be ignored if it persists for more than 24 hours.
    • If your pet had surgery of the bowels or stomach, vomiting is always a concern, as it may indicate that infection of the abdominal cavity, called peritonitis, is present.  Do not ignore this sign.
    • Symptomatic treatment of vomiting involves withholding food for 12 to 24 hours, then introducing small amounts of bland food such as rice and lean cooked hamburger, if your pet does not vomit after that then gradually wean him/her back onto the regular diet after 3 days.  In order to decrease the acidity of the stomach, Pepcid AC 0.5 mg/kg can be given by mouth twice daily for 5 days.  Metoclopramide and Cerenia are good anti-vomiting medications for dogs and cats.  You should always consult a veterinary healthcare professional before administering medication.
  • Causes and treatment of regurgitation after surgery
    • The most common cause of regurgitation is reflux of acid from the stomach into the esophagus while your pet is under anesthesia.  Acidic fluid from the stomach can cause a chemical burn of the esophagus and result in a bad case of heart burn, called esophagitis.  This results in poor motility of the esophagus, therefore water and food will accumulate in this structure.  In most cases, esphagitis is self-eliminating and will resolve within two or three days. 
    • If the esophagitis is severe the esophagus may develop one or more strictures.  A stricture is a narrowing or stenosis of the esophagus and does not allow passage of food down the esophagus, in regurgitation that lasts longer than one week.  This problem should be brought to the attention of your pet's doctor within the first two weeks so that it can be treated by ballooning the stricture (minimally invasive procedure, as it is done with the aide of an endoscope).  If an esophageal stricture is chronic surgery is needed.
    • Symptomatic treatment of regurgitation caused by esophagitis includes feeding bland food, and administering a coating agent (sucralfate) and an acid blocker (omeprazole or other).  Consult a veterinary health care professional if the regurgitation continues for more than a couple of days.

How do I know that my dog is in pain following surgery?

  • Signs of pain include
    • crying
    • biting if you get near the surgical site
    • grimacing (lips are pulled back and the the dog looks anxious)
    • tragic facial expression
    • panting
    • restlessness and unable to sleep; pacing
    • if abdominal surgery was done the pet will not lie down on the incision, or will continually sit up in spite of appearing very tired
    • the worst pain will be for the first 2 to 3 days after surgery

What can I do to control my dog's pain?

  • Narcotic medications that control pain: tramadol, butorphanol, Duragesic (fentanyl patch)
  • Anti-inflammatories used to control pain: Deramaxx, Rimadyl, Previcox, or Etogesic
  • If an orthopedic surgery has been done cold packing the surgical site may be helpful
    • A cold pack may be a pack of frozen peas, crushed ice in a Ziploc bag, or a cold gel pack; place a thin barrier between the skin and the cold pack.  An alternative to a cold pack is to freeze water in a styrofoam cup; after frozen cut the bottom of the styrofoam cup out. Cool the surgical site around the incision by rubbing the exposed ice directly on the skin in a circular pattern.  Cooling the surgical site helps to numb the area.

How do I know that my cat is in pain following surgery?

  • Pain is more difficult to assess in cats versus dogs, as signs can be more subtle and they usually do not vocalize when in pain
  • Signs of pain in a cat include the following:
    • biting if you get near the surgical site
    • growling or deep cry
    • not wanting to eat
    • hiding and not wanting to be near owner (remember that this could also be caused by the cat just being upset about leaving home and coming back)

What can be done for pain at home for my cat?

  • Pain medication such as buprenorphine or a Duragesic (fentanyl) patch
  • Tylenol will kill a cat as they lack abundant glutathione enzyme in the liver
  • Anti-inflammatories can be used, but the dose is much less than dogs

Is it okay for my pet to lick the incision?

  • If a dog licks the incision, the healing process may be delayed.
  • Licking can remove stitches and cause the incision to open
  • Licking can become a severe habit that is difficult to break
  • Licking can cause infection as the mouth has many bacteria
  • Dogs will frequently lick the incision when the owner is not watching such as at night time; if the skin looks red or excoriated the most common cause is from licking.
  • To stop your pet from licking the following can be tried:
    • Elizabethan collar can be placed on the neck; this will not help stop your pet from scratching at the region
    • Cervical collar (bite not collar) is a less awkward device and can be effective at stopping a pet from licking the surgical site
    • A tee shirt can be used to cover an incision on the chest or front part of the abdomen; gather the waist of the shirt up over the dog's back and wrap an elastic band around this part of the shirt.
    • A bandage or sock can be used to cover an incision on a limb; fasten the top of the sock to the dog's limb with tape.
    • Bitter apple can be applied around the incision; many dogs will continue to lick  after application of this topical
    • Bitter Apple and Liquid HeetTM (obtain this from a drugstore...it is used for sore muscles) mixed in a 2:1 ratio can be applied around the skin incision
    • Antipsychotic medication in some cases is needed

Board-certification by the American College of Veterinary Surgeons

What does it mean?

  • Four years of advanced training in surgery beyond the Doctor of Veterinary Medicine Degree

  • Experience in the development of new surgical treatments

  • Rigorous examination by the American College of Veterinary Surgeons to ensure competency in advanced surgical techniques

  • Assurance that a veterinarian is a surgical specialist

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