complications of bone healing Flashcards
Fracture Monitoring
- how often
- why
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- 4 As
Generally Radiographs every 4 weeks until healing
* Rule out complications
* Monitor progression of healing
> Adapt activity animal
* Confirm healing
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Four A’s
* Alignment (Alignment of bone and joints above and below)
* Apposition (apposition of bone fragments)
* Apparatus (selection, application and integrity of implants)
* Activity (bone activity: infection, resorption, healing…)
* ‘s: soft tissues (swelling…)
Complications of Bone Healing
- types?
- rates?
- Delayed union
- Non-union
- (Mal-union)
- Infection
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Complications can be minimized but cannot always be avoided
> Overall, maybe 5-10%
Delayed Union
- what is this?
- causes?
Delayed union is a fracture that heals more slowly than expected (for the same age, same fracture, same fixation etc…)
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The main causes are Biological or Mechanical
Most freuqent by far:
* Vascular insufficiency/impairment
* Fracture instability
> Inappropriately chosen or applied implants
> Implant failure
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Also:
* Infection
* Lack of soft tissue coverage
* Large gap or comminution
Vascularity - importance for healing? how it gets compromised?
- Vascularity of the bone and soft tissues is essential for FX healing
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Soft tissue trauma is the most common cause of compromised vascular supply - Original injury
- SURGICAL
> Proper surgical technique
> Do not strip periosteum or muscle attachments
> The health of soft tissue surrounding the fracture is as important (more?) as the bone itself
Host Factors for vascularity
- Toy and miniature breeds have decreased vascular density of the radius compared to large breed dogs
- Minimal soft tissues surrounding the distal radius
> Relatively high rate of nonunion fractures of the distal radius in small dogs > Better fixation required
Stability - why is it important for fracture healing? what if its not present?
Fractures require STABILITY to heal
* Callus size increases with mild instability but excessive instability result in tearing of blood vessels attempting to cross the fracture gap, bone resorption and failure of the callus to transform into bone
Infection - how it affects healing? can we overcome it?
Infection
* Infection promotes tissue ischemia and necrosis
* Promotes bone resorption and implant failure
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Bone can heal in the presence of infection Only if:
* Infection is somewhat “under control”
* The fracture REMAIN stable
Delayed Union: diagnosis
Serial radiographs (4-6 w)
* Compare to similar fractures with similar fixation
* Experience, literature etc…
delayed union treatment
Correct the cause if possible
* Improve stability
> Additional implants?
> Restrict activity?
* Apply bone graft?
* Control infection?
* DO NO HARM
Conservative
Non-Union - Pathophysiology
- what is it?
- how it arises?
- A non-union is a fracture that failed to unite. > Same causes as delayed union
- Not going to unite unless significant actions are taken
<><><> - Bone reacts to injury by forming a callus
- Callus formation decreases after ≈ 2 weeks if collars of callus do not bridge
- External bridging callus is also important for stability and osteogenic repair tissue
> (stability required to transform granulation tissue into fibrous tissue, into cartilage and ultimately into bone)
Non-Union
- Diagnosis
- What do we do?
- prognosis
- Lack of significant fracture progresses (or negative progresses) on 2 or more consecutive sets of radiographs
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Surgical intervention will be required! - Debridement of the avascular bone
- Re-opening of the medullary cavities
- Restoration of bone-bone contact
- Rigid fixation
- BONE GRAFT
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Infection
- how common with fractures?
- signs
- causes
- radiographs
- Approximately 5% of fractures
- Persistent swelling and exudation from incision
- Recurrence of lameness, pain on palpation
- Draining tracts, implant exposure
- Radiographic signs of infection
> Periosteal reactions
> Bone resorption
> Implant loosening
Infection: diagnosis in young animals? things to watch for?
Sometimes, young animals heal aggressively
* Resembles osteomyelitis
* No clinical signs
> Using leg well
> No pain on palpation
> No evidence of implant loosening
> Cultures negative (if taken)
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Recheck radiographs in 2 weeks
* Radiographic appearance should improve quickly
Infection:
- diagnosis, tests
- Tx
- prognosis
Obtain fine needle aspirate
* From plate or bone. Not fistulous tract!
* Sterile skin prep
* Culture/sensitivity
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Start on empirical antibiotics until results
* AT LEAST cover: Staph, Strep, E Coli
* Consider Multi drug resistant bacteria if dog was on antibiotics
> Doxycyclin, ampi/enro, clindamycin, chloramphenicol, amikacin…
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* If open wound, treat as infected wound until closed
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Surgery is required if
* Implant failure / instability
* Severe deep seated osteomyelitis
> Unresponsive to treatment
* Large open wounds
* Dead bone/sequestrum
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* Re-evaluate and adapt treatment q2-3 weeks
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* Continue antibiotics until fracture healed and signs resolved (8-12 weeks)
* Implants will have to be removed
* Prognosis fair to guarded but $$$
