Stabilization of midshaft comminuted fractures
with multiple fragments. These fractures are realigned
using indirect reduction techniques (see p. 1061). Because
no load sharing occurs between the implant and the bone
until biological callus forms to provide support, these fractures
need rigid axial, rotational, and bending support. Very
high stresses will be imposed on the implant and its connection
to the bone. If the biological assessment is favorable, the
imposed stresses will be of short duration, reducing the
likelihood of implant failure. If the biological assessment is
not favorable, however, imposed stresses will act on the
implant for an extended period, making implant failure
more likely. Enhancing the biological response by applying
the concept of bridging osteosynthesis (see pp. 1056) and
inserting an autogenous cancellous bone graft (see p. 1062)
is recommended.
Fixation systems useful in managing patients with a low
fracture assessment score (0 to 3) include a bone plate–pin
combination. Patients with a moderate fracture assessment
score (4 to 7) may be treated with a bone plate functioning
as a bridging plate with an IM pin or an interlocking nail.
An external skeletal fixator, with a tie-in to the IM pin, may
also be used. A patient with this type of fracture would have
a high fracture assessment score (8 to 10) only when the
biological assessment is extremely favorable (e.g., 4- to
5-month-old animal with a closed, single-limb injury).
These animals may be treated with bridging osteosynthesis
with an IM pin, with a tie-in to a type Ia external skeletal
fixator (Fig. 33-91). Immature dogs may be treated with
elastic plating techniques using a veterinary cuttable plate
and screws (see p. 1089).