How long does it take for a broken bone to heal?

How long does it take for a broken bone to heal?


I’m frequently asked how long it takes for a broken bone to heal, especially by owners who are dreading the prospect of keeping their hyperactive dog on short leash walks.

Bone healing time varies depending on several factors including the age of the dog or cat, the location and complexity of the fracture, the amount of associated soft tissue damage, and the type of repair that was performed.

Wire in femur

Residual wire in old fracture: This was a dog who presented for evaluation of the cruciate ligament (notice the effusion and arthrtis in the knee joint). As an incidental finding it looks like this dog had a femoral fracture when it was quite young. The original repair was likely a pin and wire, with the pin being removed afterward. As the bone grew, it engulfed the wire, which is why the diameter of the wire loop is less than that of the adult bone.

Age: Younger dogs or cats heal faster. They are already producing new bone in order to grow, and the cellular /chemical processes for growing bone are the same as those needed to heal a fracture; enzymatic momentum is on their side. Juvenile pets heal broken bones 2-4 weeks faster than adult pets.

Fracture location: Regions with an abundant blood supply heal faster. Some regions are easier to immobilize than others and immobilization acclerates repair.

Fracture complexity: A simple two piece fracture with no displacement of the bone ends and no disruption of the surrounding soft tissue is going to heal much faster than a high energy fracture with many broken fragments that are widely displaced. Infection slows the healing process even further.

Associated soft tissue damage: Again, regions with an abundant blood supply heal faster. Soft tissue damage compromises blood supply during the initial healing stages. Extensive soft tissue damage in a region that already had minimal soft tissue (e.g.: the front leg just above the wrist) doubly complicates healing.

Healed Femoral Fracture

This is another view of the same dog. Notice that the associated hip dysplasia. Unilateral hip dysplasia can be the result of injury during puppyhood and failure to properly weight bear on the limb as the hip joint is developing. A comprehensive rehabilitation program that encourages early and full weight bearing after surgery may reduce the chance of this happening.

Type of repair: A perfect repair immobilizes the bone without disrupting any of the surrounding soft tissue. This is not always possible to achieve, but it is something that surgeons strive for. In developing a treatment plan and/or discussing your therapeutic options (e.g.: casting or splinting vs. surgical repair), your surgeon will automatically gravitate toward the therapy that will offer the most rapid healing.

For most adult dogs or cats, broken bone healing time is 8 to 12 weeks.  In puppies or kittens, broken bone healing time is 6 to 9 weeks.  Complicated fractures can take as much as 16 weeks.

Delayed Union and Non-Union Fractures.

If a fracture is not healing as fast as expected, it is called a “delayed union” and may just need more time. If that same fracture is given more time and nothing changes, it is called a Non-Union.

Non-Unions require further intervention, which usually means more surgery. Supplementing or changing the type of repair, stimulating blood flow by debriding tissue, and/or adding a bone graft are typical treatments.

Posted on in Broken bone, Case Reports, Radiographs