Fractures Caused by Poor Husbandry
Fracture of the Calcaneus Bone (Heel Bone)
In the past 30 odd years I have been presented many times with hand reared
macropods of various species with fractures of the Calcaneus. Fig 1 and
Fig 2 show schematics of a dog calcaneus but the macropod would look similar
except the metatarsals are different.
The history is always the same. The Joey got out of his pouch and hopped down
the hallway and suddenly went lame.
In the early years we tried splinting these and keeping them in the pouch and
although they did heal the outcome, as far as mobility goes, was poor.
Sometimes the deviation was so far medial and cranial that the hock joint was
perpendicular.
For the past 15 years I have been treating these with orthopaedic surgery.
FROM "HANDBOOK OF SMALL ANIMAL ORTHOPEDICS
& FRACTURE TREATMENT" BINKER, PIEMATTEI & FLO.
Fig 1
(A) Fracture of the tuber calcanei. (B, C)Two Kirschner wires, 0.045" or
0.062" in diameter, placed side by side, as far medially and laterally as
possible. Note that the tendon of the superficial digital flexor has been
retracted medially. The exact position of the transverse hole for the wire is
not critical and is usually at midshaft or slightly distal as shown here.
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FROM "HANDBOOK OF SMALL ANIMAL ORTHOPEDICS
& FRACTURE TREATMENT" BINKER, PIEMATTEI & FLO.
Fig 2
(A) Fracture of the shaft of the calcaneus. (B,C) A single Steinmann pin,
5/64" to 1/8" in diameter, has been countersunk in the tuber. This pin
position allows the wire to be placed through a drill hole in the tuber, which
minimises irritation of the tendon of the superficial digital flexor. A single
pin is used when the fracture reduces well and is stable relative to rotation
in the reduced position. (D) If the fracture line is smooth or slightly
comminuted, two smaller countersunk pins or Kirschner wires in the sagittal
plane are used because they provide more rotational stability.
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The fractured bones are realigned and held in place with a pin and a tension
band wire. The tension band wire is necessary to counter the pull of the
Achilles tendon. The pins and wires are usually removed after 5-6 weeks.
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Grey kangaroo with Fracture of Calcaneus.
(Hock extended)
In Extension the gap opens up between fragments.
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Grey kangaroo with Fracture of Calcaneus
(Hock flexed)
The arrow points to the actual fracture site.
In flexion the fragment is pulled
up by the tendons and the actual fracture face is now pointing downwards almost
90 degrees to its true position.
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Agile Walaby
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Agile Walaby 2.5kg female
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The proximal fragment has been replaced in the correct position and a short
Steinmann pin has been placed through both fragments and right into the tarsal
bone. A hole was drilled distal to the fragment and a 22gauge
stainless steel wire was threaded through then passed around the pin in a
figure 8 and tied. It is this wire that will oppose the pull of
the tendons and prevent the pin bending. The excess pin is cut off
just above the the wire where it exits from the end of the Oss calcis.
The pin and wire are removed after 5-6 weeks at a second operation. Success rate is >
80% for a return to full viability. Always give calcium supplements.
It is not unusual to get more than one case from the same carer so
always look to the husbandry of that carer.
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