Fracture Complications Flashcards
list potential fx complications
- Delayed unions
- Nonunion
- Malunion
- Osteomyelitis
- Implant Failure
- Fracture Disease
- Implant/Fracture associated neoplasia
Local factors of fx healing
- Instability
- Vascular impairment
- Infection
- Open fractures
Systemic factors of fx healing
- Old age
- Significant concurrent disease/injury
- Poor nutrition
- Delayed return to function
- Unrestricted exercise
when is vascular supply deemed poor
- poor pre-existing muscle (distal tibia/radius)
- high energy comminuted/open fxs
- sx trauma/approach high
define strain
% of how much a fx fragment moves on weight-bearing compared to the size of the fx gap
amount of strain tolerated by bone tissue
<2%
a highly unstable fx w/ good blood supply =
large callus formation
tx of a well aligned and stable delayed union
give time and monitor w/ q4wkly rads
if suspect osteomyelitis –> C&S –> infected but stable = tx w/ ABs from C&S
tx of unstable delayed union
- remove implants - realign and stabilise
- C&S of implants
+/- cancellous bone graft
tx of unstable and infected delayed union
- remove implants –> C&S –> longterm ABs
- 1-5L warm saline lavage
- realign + stabilise
+ cancellous bone graft
two types of non-unions
- Viable (hypervasc) non-union
2. Non-viable (avasc.) non-union
rad appearance of hypervasc. non-union
abundant mineralised non-bridging callus w/ a radiolucent line separating the proximal and distal parts
tx of hypervasc non-union
caused by fx instability
–> remove implants (C&S) –> replace w/ rigid fixation (plates) + lavage like hell
rad appearance of non-viable non-union
Significant bone resorption @ fragment ends and no evidence of bone xn.
The bone ends are sclerotic and there is typically complete closure of the medullary canal w/ cortical bone.
Osteoporosis of the bone usu. apparent
+/- sequestra
tx of non-viable non-union
- Aggressive resection of the fibrous tissue and debridement of the fragment ends to open the medullary canal.
- Any necrotic bone or bone w/ no soft tissue attachment should be removed and submitted for C&S in addition to implants that are removed.
- Rigid stabilisation w/ bone plate
- Cancellous bone graft!!! (after 1-5L lavage) *can delay if site obviously infected
5 types of malunion
- overriding
- angular
- rotational
- distracted
- intra-articular
indications to tx malunion
if signif. functional impairment exists/will exist
tx of malunion
- Osteotomy
- Debridement
- Realignment
- Stable fixation
- Cancellous bone graft
2 main causes of osteomyelitis
endogenous (haematogenous) or exogenous
polyostotic, metaphyseal osteomyelitis in a 9month old collie is most likely…
haematogenous origin
define sequestrum
a piece of avascular bone separated from the surrounding living tissue. The sequestrum serves as a nidus for chronic infection - ideal for anaerobes.
define involucrum
highly vascular new bone which walls off a sequestrum. the involucrum isolates infection but limits ABs and immune system access
tx of osteomyelitis
empirical amoxicillin/clav whilst waiting for C&S –> ABs for 4wks (acute)/ 6-8wks (chronic) and reassess
rad signs of osteomyelitis
only obvious 3wks after infection –> lysis + new bone production at the metaphysis
methods of obtaining a sample to C&S with suspect osteomyelitis
- remove implants
- FNA
- swab of infect bone
- Jamshidi biopsy needle
approach to suspect acute exogenous osteomyelitis
- If animal initially improves w/ respect to weight-bearing after sx and then lameness increases after 5-7days
- –> take rads to rule out early implant failure
- –> deep tissue C&S + empirical ABs (amoxicillin/clav)
- –> implant replacement if unstable + analgesia
- Monitor for resolution of pyrexia and inc. weight-bearing on C&S ABs
a draining sinus tract that temporarily heals (spont/ABs) and then breaks out again is a hallmark of…..
chronic osteomyelitis
why is it useless to culture a draining sinus tract?
full of opportunistic polymicrobes and the causative agent is rarely IDed
if suspect chronic osteomyelitis you send a deep tissue sample for what cultures?
- aerobic
- anaerobic
- fungal
3 factors to result in a sequstrum
Bacterial contam + avasc. fx fragment + high strain environment
rule of thumb = if there are more than 3 fragments use…
biologic/bridging osteosynthesis approach w/ open but do not touch sx repair approach
most common pathogen of osteomyelitis
B-lactamase producing Staph. intermedius and aureus
other pathogens of osteomyelitis
E.coli, Pseudomonas, Strep, Proteus
anticipated healing time of infected non-unions =
3-6months
suitable options to stabilise an infected non-union fx
- plate
- interlocking nail
chronic osteomyelitis req. AB for what time frame?
6-8wks minimum
4 factors involved in exogenous osteomyelitis development
- bacteria: number/type
- Extent of soft tissue damage + impaired blood supply
- Stability of fx repair
- Formation of a biofilm (glycocalyx) over implants
biofilms do what for bacteria
- facilitate bacterial adhesions to implants
- protects bacteria from phagocytes, antibodies and ABs
how do you avoid chronic fatigue implant failure?
always use fracture assessment + planning
Why does femoral fx repair by retrograde IM pin placement cause disuse atrophy?
the pin cannot be cut level w/ greater trochanter thus irritates the gluteal muscles/forms a fibrous seroma –> dog uses leg less
3 types of fracture dz
- Disuse atrophy
- Adhesions/contractions
- Joint disease
how do you prevent fracture dz?
- physio
- analgesia
- minimising surgical trauma (Halsted’s principles)
- rigidly stable fixation of fxs
when should you recommend removal of implants following fx healing?
- Grade 2-3 open fxs
2. Osteomyelitis
