The Shortened Radius Syndrome

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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

www.animalsurgicalcenter.com

Phone: 810-671-0088

Key Points

If the growth plate of the radius bone is damaged while a dog is growing, there is a significant risk that the patient may develop a shortened radius bone which ultimately causes the elbow joint have an imperfect fit.

Treatment of this condition usually involves removing a segment of the ulna bone, just below the elbow.

Surgery usually will dramatically improve the lameness, yet heavy exercise in these patients may cause some stiffness or lameness.


Pertinent anatomy

  • The elbow joint is formed by the the ends of the humerus bone, radius bone and the ulna. It is critical that each bone fits perfectly within the elbow joint so that abnormal wear and tear on the joint does not occur. In addtion, abnormal stresses may be placed on coronoid process, may cause this part of the bone to break off (called a fragmented coronoid process).

 

Pathology of a shortened radius bone

  • The long bones of the body have a growth plate located at each end. The longitudinal growth of the bone occurs at the growth plate. If the growth plate is damaged while a dog is growing (major growth in large breed dog takes place from 4 to 8 months of age), then the affected bone may be shorter than normal.
  • If the growth plate of the radius (either the top or bottom one) is damaged the radius bone becomes shortened. The result frequently is two fold:
    • the elbow gets pulled out of alignment and more weight is then put on the medial and lateral coronoid processes, thus these processes may break off
    • the carpus (wrist) may develop abnormal twisting

 

Signs of a shortened radius bone

  • Most dogs are under one year of age when this problem is first dagnosed
  • Breeds commonly affected are Bernese Mountain Dogs and less commonly Retrievers and Mastiffs
  • Affected dogs are commonly lame on the affected forelimb. These dogs may externally rotate the forelimb in order to relieve elbow pain. In other cases, the affected limb may have a true rotational abnormality due to twisting of the bones from abnormal growth.
  • The elbow may be swollen and painful on direct palpation.

 

Diagnosis

  • Frequently a shortened radius can be seen on plain radiographs (x-rays) of the affected forelimb (see below)
  • CT scan may also be used to help diagnose secondary issues such as a fragmented coroinoid process within the elbow joint

 

Treatment

  • The simplest treatment for this condition is to remove a segment of ulna bone, just below the elbow joint. The amount of bone that is removed is inversely proportional to the dogs age. In other words, if the dog is young (ie about 5 months old) then a much larger segment of bone should be removed from the ulna bone versus a dog that is no longer growing (about 10 to 12 months old). I prefer to place a pin in the ulna bone for alignment and also pull the cut ends of the ulna bone together with a heavy nylon suture so that that elbow joint will assume a better fit immediately after surgery. The space between the cut ends of the ulna bone eventually heal together, but this process may take about 3 months.
  • A more complex form of treatment is to lengthen the radius bone, but this should be reserved for dogs that have stopped growing.
  • Regardless of the type of treatment used to make the elbow joint fit better, arthroscopic examination of the joint is recommended at the time of surgery to rule out the possiblity of a fragmented coronoid process. If this is the case, the loose fragment of bone is removed from the joint at that time.

Preop radiograph showing a shortened radius and a 6 mm of radiohumeral incongruity

Preop radiograph showing a shortened radius with the coronoid process riding high

Immediate postop radiogaph showing dramatic improvment of the congruity of the elbow joint after a proximal partial ulnar osteoctomy. In this case 1.5 cm of bone was removed and a pin placed.

Immediate postop radiograph showing dramatic improvement of the congruity of the elbow joint. Take note of the poximal ulnar ostectomy site and the which aligns the ulna. The step in the elbow has been eliminated.

 

Prognosis

  • A report of 11 dogs that were treated for shortened radius bone syndrome for the most part were significantly improved. Lameness associated with heavy activity was noted in most dogs.

 

References

  1. Vandewater A and Olmstead ML. Premature closure of the distal radial physis in the dog: a review of eleven cases. Vet Surg 1983;12 (1):7-12
  2. Cook CR, Cook JL. Diagnostic imaging of canine elbow dysplasia: a review.Vet Surg. 2009 Feb;38(2):144-53
  3. Samoy Y, Van Ryssen B, Gielen I, Walschot N, van Bree H. Review of the literature: elbow incongruity in the dog. Vet Comp Orthop Traumatol. 2006;19(1):1-8. Review.
  4. Preston CA, Schulz KS, Taylor KT, Kass PH, Hagan CE, Stover SM. In vitro experimental study of the effect of radial shortening and ulnar ostectomy on contact patterns in the elbow joint of dogs. Am J Vet Res. 2001 Oct;62(10):1548-56
  5. Ubbink GJ, Hazewinkel HA, van de Broek J, Rothuizen J. Familial clustering and risk analysis for fragmented coronoid process and elbow joint incongruity in Bernese Mountain Dogs in The Netherlands.Am J Vet Res. 1999 Sep;60(9):1082-7.
  6. Boulay JP. Fragmented medial coronoid process of the ulna in the dog. Vet Clin North Am Small Anim Pract. 1998 Jan;28(1):51-74.

 

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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