10 long bones, fractures Flashcards
apart from type 5 salter harris fractures, does the type of salter Harris injury affect the prognosis for the dog or cat?
yes or no
in canine type I and II physeal injuries it has been shown that the fracture line is not restricted to the zone of hypertrophy but rather meanders through all the zones, including the germinal layer. Hence, the type of injury does not influence the prognosis for future growth.
how much longer do open fractures take to heal on average, compared to closed fractures?
a- 10% longer
b- 40% longer
c- 50-100% longer
d- 200% longer
c
what is the definition of a short oblique fracture?
A short oblique fracture line has a length that is less than approximately twice the
diameter of the bone. The significance of this is that it is difficult or impossible to apply interfragmentary compression in a short oblique fracture using lagged
bone screws or cerclage wire.
what is the definition of a comminuted fracture?
A comminuted fracture is one in which there are several fragments and the fracture lines communicate. Substantial
fragments include the proximal and distal ‘segments’ and butterfly fragments. The latter are defined as those fragments that are reducible and can be stabilized by application of interfragmentary implants
such as lagged bone screws or cerclage wires. Small fragments are those that cannot be reduced and stabilized in this way. This leads to comminuted
fractures being classified as either ‘reconstructable’ or ‘non-reconstructable’
what is a segmental fracture?
A segmental (or multiple) fracture is one in which the bone is broken into three or more segments such that the fracture lines do not communicate
what is the problem with this fracture fixation?
a) transcortex defect
b) poor alignment
c) inappropriate activity
A- can add stress to the plate and lead to implant failure
the diameter of screws or external fixator pins used to fix a fracture should be what diameter compared to the size of the bone?
a- less than 1/10 of the
diameter of the bone they are being placed into
b- no more than1/3 of the
diameter of the bone they are being placed into
c- no more than 1/4 of the
diameter of the bone they are being placed into
d- 1/2 of the
diameter of the bone they are being placed into
B
in ideal conditions, which cells are developed, allowing rapid bone healing?
a) fibroblasts
b) chondroblasts
c) osteoblasts
C. produce woven bone rapidly. In less
ideal conditions of stability and oxygen tension, where osteoblasts would not survive, the mesenchymal cells differentiate into chondroblasts, producing hyaline cartilage that becomes mineralized and converted to bone by the process of endochondral ossification. When the tissue
is under tension (e.g. avulsion fractures), the mesenchymal cells differentiate into fibroblasts that produce fibrous
tissue. This is an undesirable situation because such tissue does not enhance stability to allow the invasion of
more appropriate cell types, nor does it have the ability to mineralize and become more stable.
inadequate healing is usually a result of…
instability
overstability
infection
instability.
delayed or non-union may result from one or a
combination of factors, including:
* Inadequate stabilization
* Poor vascularity
* Excessive fracture gap (± interposition of soft tissue, a
loose implant or devitalized bone fragment)
* Infection
* Systemic or local disease
* Idiopathic factors (generally relating to atrophic
non-union).
periosteal stripping and damage to the attachment site of which muscle leads to this appearance?
rhino callus, adductor muscle. seen more in young dogs
which classification most accurately matches this description?
* Gap between fracture ends
* Closed medullary cavity (unless pinned)
* Smooth fracture surfaces
* Sclerosis of fracture ends
* ± Hypertrophy or atrophy of bone ends.
a) delayed union
b) non- union
c) malunion
B
is hypertrophic non- union viable or non- viable?
viable (biologically active). Hypertrophic non-union (‘elephant’s foot’ callus if moderate, horse foot if mild.). There is abundant callus formation but failure to bridge the fracture gap, usually due to rotational instability. This type of non-union is most commonly seen in simple (transverse or short oblique)
humeral or femoral
is oligotrophic non- union viable or non- viable?
viable. Oligotrophic non-union. In these cases there is no, or very limited, callus formation. The usual causes are either an avulsion injury treated conservatively or as above for slightly hypertrophic
non-unions in small or toy breed dogs. Additionally, if non-union results from a related systemic disease, e.g. hyperadrenocorticism, then it is this type of non-union that might be expected.
what is the difference between viable and non- viable non- union?
Although instability may play a role in the aetiology of non- viable nonunions,
there is usually a barrier to healing. where as viable ones it is usually just instability.
which of this is not a type of non- viable nonunion?
a) dystrophic
b) necrotic
c) Atrophic
d) oligotrophic
D. defect non- union is also non- viable. The terminology used for these classifications may
be misleading in that the term ‘non-viable’ suggests healing
will not take place whereas it will in a viable non-union.
In fact, healing will not occur in either type without surgical
intervention and the prognosis for non-viable non-unions
is reasonable, with appropriate management. The exception
to this is the case of atrophic non-union where the
cause is poorly understood and treatment is recognized to
be difficult and often unsuccessfu
what is the lesion in the calcaneous?
ring sequestrum
