The healing times of broken legs in dogs may vary based on several factors. In order to better understand the process of healing, it helps to gain a closer insight into how bones are structured and how different types of fractures impact them. If your dog broke his leg, it's important to see veterinary attention immediately, considering that your dog is in pain, but also to ensure the bone heals in the correct way. The earlier the fracture is taken care of, the better. In this article, veterinarian Dr. Ivana Crnec discusses broken bones and the healing times of broken bones in dogs.
Broken Legs in Dogs
Bones in dogs come in many shapes and sizes, ranging from flat plates that anchor large muscle masses, such as the shoulder blades, to hollow, thick-walled tubes that support weight or act as a lever, such as those in the legs.
Bones have two layers. The cortex (outer layer) is made up of dense, heavy, compact tissue covered by a membrane called the periosteum. The medulla (inner layer) consists of spongy bone that has many struts (trabeculae). These struts are arranged to provide maximum support without adding excessive weight.
Although it may appear to be lifeless and unchanging, the bone tissue is actually a living tissue, supplied with nerves and blood vessels and it is constantly being broken down and rebuilt.
Types of Bone Fractures in Dogs
Bones can break in many ways and therefore, there are different types of fractures in dogs. To make things simpler and easier, bone fractures can be classified in the following categories:
In this case, the break spreads only partway around the bone’s circumference. Incomplete fractures are more like a bend and are commonly seen among young dogs. Basically, young dogs can break their bones in much the same way as a young tree branch cracks, but does not separate when you bend it. These fractures are popularly known as "greenstick fractures" or "hairline fractures." They look like small cracks and slivers in the bone.
In this case, the break spreads through the bone’s full circumference which results in formation of two or more bone fragments. Based on the shape of the break, complete fractures can be sub-classified as:
- Transverse – the break spreads across the bone at a right angle of the bone’s length. Oblique – the break spreads diagonally across the bone thus creating two sharply pointed bone fragments. Comminuted – the break results in three or more differently shaped bone fragments.
Bone fractures can also be classified as:
Compound Fractures (Open)
A compound fracture is obvious because the bone sticks through the skin. They occur when the broken bone penetrates the skin (inside-out) or when an object goes through the skin and breaks the bone (outside-in). Compound fractures are prone to contamination by dirt and bacteria because the wound is exposed.
Simple Fracture (Closed)
When there is no open wound. In a simple fracture, the bone is not visible, but the break causes pain and swelling.
Littermate Syndrome: Risks With Getting Two Puppies at Once
If you're getting two puppies at once from the same litter, you'll need to be aware of littermate syndrome, also referred to as "sibling syndrome" or sibling rivalry. As tempting as it can be to bring home two adorable puppies, there are certain implications to consider at a rational level before giving in to your impulse and listening to your heart.
Discovering Why Dogs Keep Their Mouths Open When Playing
Many dogs keep their mouths open when playing and dog owners may wonder all about this doggy facial expression and what it denotes. In order to better understand this particular behavior, it helps taking a closer look into how dogs communicate with each other and the underlying function of the behavior.
Should I Let My Dog Go Through the Door First?
Whether you should let your dog through the door first boils down to personal preference. You may have heard that allowing dogs to go out of doors first is bad because by doing so we are allowing dogs to be "alphas over us," but the whole alpha and dominance myth is something that has been debunked by professionals.
Causes of Broken Legs in Dogs
Most bone fractures in dogs are caused by traumatic incidents such as car accidents and falls from a height. Rarely, fractures may occur due to pathological weakening of the bone due to neoplastic conditions (eg. osteosarcoma, bone cancer).
Dogs usually fracture the major bones that are closest to the body (the humerus in the front limb and the femur in the hind limb). Other frequently broken bones include the skull, the jaw, the spine and the pelvis.
All dog breeds are equally predisposed to bone fractures. However, it goes without saying that toy breeds have more fragile bones. Generally speaking, fractures are more common among young puppies, older dogs and dogs with adventurous and excitable personalities.
At The Vet's Office
The vet will first make sure that there are no life-threatening injuries, then give medications to control shock and pain, and intravenous fluids or blood as necessary, before attending to the fracture. In a nutshell, the diagnosis of a broken bone occurs in three steps: Taking a thorough history (to differentiate between traumatic and pathological fracture), physical examination and evaluation of the findings, x-rays, of the affected leg (several images taken from different angles).
How are broken legs treated in dogs? Usually, the actual bone treatment begins several days after the initial accident – once the shock, blood loss and pain are successfully managed. There are two treatment approaches: Conventional (using splints and casts) and surgical ( using pins, screws, wires, plates).
Which treatment option will be selected depends on several factors, such as patient factors: size, weight, age, breed, activity level, client factors: compliance, finances, husbandry, fracture factors: location, configuration, forces, contamination, and veterinarian factors: knowledge of implants and implant availability.
Healing Times of Broken Legs in Dogs
What are the healing times of broken legs in dogs? Luckily, fractures heal and bones tend to resume their normal shape, structure and mechanical strength. The healing process is also known as remodeling process and it includes 4 different phases:
- Inflammatory phase I – begins few hours after the injury. It is characterized by inflammation of the damaged area around the fracture site (redness, swelling and blood clot formation).
- Inflammatory phase II – the blood clot transforms in connective (granulation) tissue. The granulation tissue provides a protective capsule for the immune cells and growth factors responsible for new bone formation.
- Repairing phase – the granulation tissue turns into callus (a temporary splint that connects the broken ends). It occurs in two stages:
- Soft callus formation – the osteoblasts create the new bone by secreting unmineralized organic matrix called osteoid.
- Hard callus formation – the osteoid is mineralized and forms a so-called woven bone. The woven bone is structurally different than the regular bone. It is made of randomly placed collagen fibers and it is mechanically weak. The hard callus serves as a bridge between the existing bone and the new bone.
- Remodeling phase – in this final phase the woven bone converts into lamellar (regular) bone.
Healing times of broken bones in dogs depends on several factors such as:
- Age – the healing process is much faster in younger puppies because they have more osteoblasts (bone building cells). The general healing timeframe is:
- Puppies less than 3 months: about 2 to 4 weeks
- Puppies 3 to 6 months: about 1 to 3 months
- Puppies 6 to 12 months: about 1.5 to 5 months
- Dogs over 1 year: about 2 months to 1 year
Other factors to consider:
- Lack of exercise prior to injury – regular physical activity is good for maintaining muscle mass and preserving joint flexibility.
- Obesity – extra pressure on the bones and joints impairs the bone’s ability to heal.
- Poor nutrition – the bone formation process requires mineralization. If the dog lacks the nutrients that promote bone remodeling, the repair time will be prolonged.
- Severity – the blood clotting process around the fracture site is affected by the fracture’s severity. The fracture’s severity also affects the duration of the repair tissue formation.
- Pre-existing conditions – the healing rate can be affected by joint disorder, previous surgeries, cartilage deterioration and nutrient deficiencies.
- Infections – when the bone is exposed, the risk of bacterial contamination and infection is high. Infections delay the healing.
- Excessive movement – too much movement prolongs the healing time because it causes delayed union of the broken ends.
- Delayed visit to the vet’s office – the sooner the treatment begins the higher the healing rate.
About the Author
Dr. Ivana Crnec is a graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia.
She currently practices as a veterinarian in Bitola and is completing her postgraduate studies in the Pathology of Domestic Carnivores at the Faculty of Veterinary Medicine in Zagreb, Croatia.
Ivana’s research has been published in international journals, and she regularly attends international veterinary conferences.
Photo credits: OpenStax College CC BY 4.0 via Wikimedia Commons