Treatment of severe orthopedic infections

The majority of orthopedic and soft tissue infections in animals are classified as post-traumatic, that is, occurring after surgery or trauma. They can be further divided into wound infections involving soft tissue only and osteomyelitis, or true bone infection. Wound infections may progress to osteomyelitis or remain within soft tissue. Likewise, osteomyelitis can have a soft tissue component or be primarily confined to the bone.(6) Osteomyelitis can be expected where there has been overwhelming bacterial contamination in combination with severe trauma, surgical intervention, or the presence of dead bone, or where metallic implants are used, especially if bone or implants are unstable.(32) (68,) (82) Poor surgical technique has been implicated as being the primary cause for posttraumatic infection. This includes gross contamination of the surgical wound, prolonged wound exposure, and improper treatment of wounds contaminated by outside sources.(6) Hematogenous osteomyelitis accounts for approximately 19% of diagnosed cases in humans(82) and is estimated at a prevalence of less than 10% in dogs.(13, 74) Osteomyelitis is more likely if avascular bone is present, which can also be related to poor surgical technique resulting from unstable fracture fixation or to loss of blood supply to bone fragments.(6, 74) The persistence of deep infection is compounded by the presence of metallic implants.(32) (66,) (75) Posttraumatic osteomyelitis can occur in any breed of dog or cat and at any age. There appears to be a slight predilection for young male animals due to the increased incidence of trauma in this subset. Posttraumatic infection appears to have a predilection for long bones over bones of the axial skeleton, probably as a result of the increased incidence of fracture in long bones.(6, 13, 68, 74) Self-trauma to the site of infection is a significant problem in dogs and may result in prolongation of clinical signs.