Angular Limb Deformity

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

Key Points

The growth plates are much softer than other regions of the bones, therefore are more prone to injury

The wrist or carpus is prone to developing an injury of the growth plate of the ulna because it is "V" or cone-shaped

If the dog is beyond the rapid growth phase then both radius and ulna bones must be cut to straighten the limb

 


Anatomy

Growth plates, which are responsible for bone growth are located near the ends of the bones and are found in animals less one year of age. The majority of a dog’s growth occurs during four to eight months of age. When a pet matures at approximately one year of age the growth plates close and become invisible (or just a white scar line) on x-rays. Because growth plates are softer than other parts of the bone, they are susceptible to trauma and fracturing.

 

Growth plate injury

Because the majority of bone growth takes place by eight months of age, a growth plate trauma occuring beyond that age does not have as deliterious of an effect on the shape of the bone. Growth plates are the softest part of an immature bone, therefore are susceptible to trauma.

 

A Salter-Harris classification of growth plate fracture has been described in humans and may to relate to prognosis in dogs and cats. Type 5 injury to the growth plate is where the cells of the growth plate are crushed, but the actual growth plate is not displaced.  The result is a scar at the level of the growth plate and no additional growth of the bone occurs. If the growth plate injury occurs in one of two paired bones (one bone grows and the other does not) the final outcome is usually devastating (see fig 1 of a Rottweiler with twisted right forelimb due to premature closure of the ulnar growth plate; x-ray of a limb with the twisted carpus due to the same is seen in fig 2).

Mechanism of limb twisting

Front limb

  • The wrist or carpus is prone to developing an injury of the growth plate of the ulna because it is  is V or cone-shaped (see illustration below). An impact such as taking a fall and landing on the front limb with full force can drive this cone-shaped growth plate together and result in severe damage to the cells. This type of injury is common in short-legged dogs. Another injury can be due to damage to the blood supply to a section of the growth plate and a cartilaginous core will develop and the bone growth slows down or stops. Cartilaginous core formation is more common in giant breed dogs.
  • The growth plate at the lower part of the ulna bone (red line in illustration) is responsible for 90% of the growth of the entire bone. Therefore, the ulna essentially stops growing. The radius bone, which is the parallel bone to the ulna, continues to grow. This causes a bowstring effect, with the radius being bent like a bow due to its continued growth and the ulna staying the same length like the string of the bow.
  • The wrist therefore twists and the elbow joint also gets pulled out of alignment (see illustration). The lameness in such a case comes primarily from the elbow incongruency (dashed circle in illustration), but also may be due to stress put on the collateral ligaments of the carpus.
  • Another type of injury is closure of one side of the growth plate of the lower radius bone. In this situation the bone could twist toward or away from the midline of the pet (depending on which side of the growth plate is affected). This injury occurs when the limb is struck on one side of the foot.

      

     

Hind limb

  • The hock or ankle sometimes develops a twisting toward the midline if the growth plate has been injured on the inner side. This problem is most commonly seen in Dachshunds
  • The knee or stifle may develop a twisting away from the midline (genu valgum) if there is asynchronous growth of the bone at the lower growth plate of the femur. This problem is very uncommon, but sometimes is seen in giant breeds such as Great Danes.

Surgery

Front limb

  • If the dog is still growing and the carpus is not twisted more than 25 degrees then removing a small section of the ulna bone and its associated covering (periosteum) will usually allow the limb to become straight again as the dog grows (see fig 3).

       Fig 3

  • If the dog is beyond the rapid growth phase then both radius and ulna bones must be cut to straighten the limb (see fig 4 before and fig 5 after surgery; a circular fixator was placed to keep the bones aligned). Sometimes the elbow congruency needs to be improved by cutting the ulna bone just below the elbow joint.

       Fig 4     Fig 5

Hind limb

  • Angular limb deformity of the hock is treated by cutting the lower part of the tibia and using a plate or an external skeletal fixator to fix the bone in straight alignment.
  • If the knee is affected the periosteum is stripped on the side that is not growing as well. This can stimulate that side of the bone to grow faster and therefore the limb will straighten. This is only useful if the animal is still growing.

Potential complications

  • Anesthetic death
  • Limb continues to twist
  • Arthritis
  • Infection
  • Poor bone healing or nonhealing of the bone
  • Breakage of the surgical implants (screws, pins, plates)
  • Limb is shorter than the normal thus resulting in a gait abnormality

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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