Delayed Bone Healing Flashcards
What are the 4 major open fracture fixation types?
- external coaptation - no wound access
- IM pin/interlocking nail - spreads contamination
- external fixator - preserves blood supply, no implant at fracture site, access to wound
- bone plate
What are degloving injuries? What are the 2 types?
result of shearing forces that severe cutaneous vessels supplying the skin
- PHYSIOLOGIC - skin devitalized, but still in place
- ANATOMIC - skin avulsed from underlying tissue
Physiologic degloving:
- skin devitalized, but still in place
- if left untreated, the skin is a harbor of major contamination
Anatomic degloving:
- skin avulsed from underlying tissue
- want to support degranulation tissue for functional ankylosis to maintain ability to walk
What is the main concern with missile wounds?
increased soft tissue trauma underneath small entrance wound due to vibration of bullets
What is osteomyelitis?
inflammation of bone marrow, cortex, and periosteum, usually secondary to bacterial infection (also fungal or mixed infections)
- biopsy: fungal hyphae
- culture: bacteria
What are the most common monomicrobial, polymicrobial, and anaerobic infections isolated from osteomyelitis?
MONO - Staphylococcus intermedius or aureus
POLY - Streptococcus, Proteus, E. coli, Klebsiella
ANAEROBIC - Actinomyces, Clostridium, Bacteroides
What are the 4 causes of osteomyelitis?
- iatrogenic surgical inoculation/contamination
- open fracture
- hematogenous spread - septic translocation from GIT to the metaphyseal region (Parvo puppies)
- extension from adjacent soft tissue infection
What 4 factors are required for iatrogenic osteomyelitis development?
- inoculum of pathogenic bacterial in sufficient numbers, typically from FB that potentiate infection
- soft tissue damage - hematoma, lack of blood supply
- formation of biofilm (glycocalyx)
- unstable repair
What is bioflim?
combination of bacterial slime and host cellular debris that acts to promote bacterial adherence and protects bacteria from phagocytosis, host antibodies, and antibiotics
- reservoir for infection!
When is hematogenous osteomyelitis most common?
- immature dogs
- metaphysis of long bone
- fracture sites
What are the 5 most common acute findings on physical/laboratory exams with osteomyelitis?
- pain on palpation
- swollen and inflamed soft tissues
- pyrexia, anorexia, lethargy
- d/c from sinus tracts
- neutrophilia with left shift
What are the 2 most common radiographic findings in the acute phase of osteomyelitis?
- soft tissue swelling
- gas shadows if gas-producing bacteria present
What are the 6 most common physical exam findings in the chronic stage of osteomyelitis?
- lameness
- d/c from sinus tracts
- pain on deep palpation of bone
- disuse muscle atrophy
- intermittent soft tissue swelling
- instability at fracture site
What are the 2 types of draining tracts?
- SINUS - communication between mesothelial surface and skin, often associated with FB migration
- FISTULA - communication between 2 epithelial surfaces (e.g. tracheoesophageal fistula)
What is the most common cause of sinus tracts? What is required for complete healing?
plant material FB (grass awns, small twigs) that are swallowed, inhaled, or penetrates skin and migrates significant distances which creates a draining tract lined by granulation tissue
“pseudo” heals with antibiotic treatment, but requires FB removal (excision of tract not necessary if FB is removed!)
What are the 5 most common radiographic findings seen in the chronic stage (2+ weeks) of osteomyelitits?
- bone lysis and sclerosis in cortex and medullary cavity
- periosteal new bone in lamellar pattern oriented perpendicular to bone in a sunburst, columnar, or radial appearance
- cortical thinning
- sequestrum and involucrum formation
- delayed fracture healing or nonunion
What surgical and medical treatments are used for osteomyelitis?
debridement to remove all devitalized bone and soft tissue and provide drainage or stabilization of fracture, if needed
prolonged antibiotic therapy based on culture and sensitivity
What is important to limit the spread of osteomyelitis? What can be done to make it easier?
early aggressive removal of all necrotic bone and soft tissue
injection of 2/5 methylene blue into sinus tract 24 hours before surgery
What is an involucrum? Sequestrum?
layer of living bone formed around dead bone
necrotic bone separated from living bone
How is osteomyelitis treated when large amounts of discharge is present?
treat as an open wound
- pack with dilute Nolvsan swabs, cover with sterile dressing
- change swabs daily under heavy sedation
- once discharge resolves, close or allow to heal by second intention
How are infected, unstable fractures treated?
replace or supplement implants with external fixators or bone plates that will be removed following fracture union to resolve infection (can add a bone graft!)
(don’t remove any stable implants!)
What is the prognosis of osteomyelitis?
- conservative treatment = guarded, creates highly resistant organisms
- surgical treatment, removal of sequestra and infected tissue = good
What treatment is used for hematogenous osteomyelitis?
- prolonged course of antibiotics or antifungals
- remove sequestra (may solve infection!)
- exercise restriction
- surgical curettage in recalcitrant cases or discospondylitis or focal osteomyelitis
What is fracture-associated sarcoma? What 2 things are they most commonly associated with? In what bone is it most common?
highly malignant tumors that occur at sites of previous fractures (avg lag time of 6 years)
- internal fixation
- complicated fractures or fracture healing
diaphysis of femur
What is fracture disease? What are the 4 most common conditions?
complications that limit the use of limb, often after the fracture has healed (secondary to immobilization)
- quadriceps and flexor tendon contracture
- muscle atrophy and disuse osteoporosis
- articular and periarticular changes
- growth disturbances
How can fracture disease be prevented?
- chose means to repair conducive to early ambulation
- passive ROM exercises (NO RUNNING OR JUMPING)
- hydrotherapy
- strengthening of weak opponent muscle
What treatment can be used for fracture disease?
- physical therapy
- NSAIDs
prevention is important - reversal of severe problems is unlikely
What are pathological fractures? What are 3 common causes?
fracture without excessive trauma as a result of pre-existing bone disease
- neoplasia
- osteomyelitis
- secondary hyperparathyoidism
How are the causes of pathological fractures typically treated?
- neoplasia: amputation or limb salvage
- osteomyelitis: rigid fixation, treatment of infection
- secondary hyperparathyroidism: correction of endocrine or nutrition conditions, corrective osteotomy after bone has improved
What kind of fractures may need amputations for repair?
Type III open fractures
In what 2 situations is arthrodesis indicated?
- severe fractures of the carpal and tarsal bones
- chronic pain and instability of other joints
