An open fracture is classified as any fracture that has communication to the outside environment. Unfortunately, most open fractures have extensive skin and muscle wounds that make management of the injury challenging. Also, most animals have concurrent injuries that can be life-threatening and must be addressed before the open fracture is dealt with.

Different types of open fractures relating to the degree of soft tissue damage have been described:

 Type I: Low-energy trauma usually resulting in a simple fracture with minimal muscle damage. Small (< 1 cm) skin wound caused by fractured bone penetrating the skin from within. These fractures can often be treated as if they were closed.

 Type II: High-energy trauma with moderate muscle damage and larger skin wound (> 1 cm). There is or was communication between the skin wound and the fracture.

 Type III: High-energy trauma with extensive wounds and often significant soft tissue and bone loss. Examples are high-velocity gunshot wounds or severe degloving injuries.

 No major reconstructive surgery is required for wound management.

 Reconstructive surgery required to close wounds because tissues are not viable enough for closure.

 These wounds have major arterial injuries that require reconstruction.

 Type IV: Most severe soft tissue and neurovascular damage requiring amputation.

When faced with an open fracture, treatment decisions are not based just on the fracture configuration. Important factors to consider are severity of soft-tissue wounds and fractures, viability of tissues, degree of neurovascular damage, overall status and signalment of the animal (shock, concurrent injuries, age of patient, etc.). In case of severe open fractures, the question to be asked is: Can the limb be saved and good function achieved without further deterioration of the animal's overall condition? As with any trauma case, overall stabilization of the animal must precede treatment of a focal injury such as an open fracture (except laceration of major vessels associated with the fracture requiring immediate intervention). That said, delaying surgical stabilization beyond 48 hours has been associated with a poorer functional outcome and the open fracture should be treated at the earliest opportunity. Due to the complexity of injury, referral to a specialist should be considered after the animal has been stabilized and the wound properly addressed.

A thorough orthopedic and neurologic examination should be carefully performed. Particular attention must be paid to tissue perfusion and necrosis of the skin and wound, bleeding, temperature of the distal limb, presence of pain sensation, and other injuries apart from the fracture. Extent of the wound and contamination are important to guide treatment decision making. Radiographs (always take both views!) of the affected limb are taken with appropriate sedation and pain control. The presence of air near the fracture site is indicative of an open fracture, although air may not always be present. The contralateral limb may also be radiographed to help with surgical planning. Always include the joint above and below when radiographing fractures.

All open fractures are contaminated and considered infected if the wounds have not been managed/treated for more than 6–8 hours. Broad-spectrum bacteriocidal antimicrobials should be administered intravenously at the time of presentation and maintained through and for 2 or 3 days after the last surgery (if multiple procedures are required). For type I open fractures, a first-generation cephalosporin can be administered (i.e., cefazolin, 20–30 mg/kg IV q 6–8 h). For type II and III, a higher generation or a combination of antimicrobials should be given. Bacterial culture and susceptibility testing is performed after initial wound care if fracture repair is delayed or at time of fracture fixation. If culture results are negative and there are no signs of local or systemic infection, antimicrobials can be discontinued. Unfortunately, infection-causing bacteria are not always cultured and signs of infection may develop after surgery despite negative cultures. If this occurs, the wound should be properly managed and debrided, irrigated, and possibly recultured. Postoperative infections are often associated with systemic signs such as fever, loss of appetite, pain, edema of the affected limb, and drainage around the wound. Increased white blood cells are often noted on CBC and radiographic signs of osteomyelitis may be seen. In light of an established infection, appropriate antimicrobials should be continued for at least 6 weeks; however, they cannot replace proper wound care without which infection may be difficult to eliminate.

Proper wound care is essential and requires placement of a sterile bandage as soon as possible. All wound care must be done using aseptic techniques similar to procedures in the operating room (masks, caps, sterile scrub with gown and gloves, and sterile instruments) to avoid further contamination. The affected limb must be handled with care to avoid further trauma to soft tissues and protect blood supply. Wound care for type II and III open fractures involves copious lavage of wounds with physiologic saline solution and debridement of devitalized tissue. Fragments of bone with poor soft tissue attachment should be removed. Diligent wound care is usually necessary daily (sometimes twice daily) until healthy granulation tissue has developed. Soft-tissue reconstructive procedures can often be performed after 5 to 7 days but may also have to be staged.

Fracture repair should be undertaken as early as possible as long as the patient is stable. Stable fractures will eliminate further muscle and vascular trauma and improve pain and function. Even in light of contamination and possible infection, fracture healing should occur as long as the repair is stable and blood supply is present. Stable external or internal fixation (i.e., external fixator, interlocking nail, plate and screws) are used and further soft-tissue injury from surgery is kept to a minimum. External fixation with either closed reduction or limited open reduction is often an excellent choice for repair as external wounds can be managed and soft tissues around the fracture can be protected. External coaptation with a splint or cast is not appropriate as bandages would need to be changed too frequently for wound care to allow proper fracture stabilization.

Bone healing of most open fractures will take longer than normal due to the extent of injury and probable necrotic tissue and disruption of blood supply. This requires a stronger means of fracture fixation to prevent implant failure (generally 20–30% stronger than for similar closed fractures). Autogenous cancellous bone grafting is a very important adjunct to improve bone healing. In type I and II open fractures, bone grafting may be performed at time of fracture fixation. In type III fractures, delayed grafting may be needed a few weeks after initial fixation once soft tissues have covered bone and blood supply has been established.

Physical rehabilitation is an important part of postoperative care and should be initiated as early as possible. Complications of open fractures include osteomyelitis, sequestration, delayed or non-union, and implant failure.