Fracture repair results in the creation of a bone-implant composite. Although most of our interventions for fracture repair
are successful, at times it seems as though there are an endless number of errors that may prevent the fracture from healing.
Fortunately, once the cause of the complication is recognized, the underlying problem can often be corrected and a successful
outcome eventually attained.
Failure of a bone-implant composite can occur in one of three ways:
1.
The implant can fail
2. The attachment of the implant to the bone can fail.
3. The bone can fail to heal.
Implant failure
Implants rarely fail due to material, manufacturing, or design flaws. Instead the typical cause of implant failure is technical
error. Technical error includes poor preoperative assessment/planning, improper implant selection (i.e. the selected implant
is inadequate to counteract the forces at the fracture site), and improper application of the implant.
Attachment of the implant to the bone
A set of guiding principles exist for the selection and application of implants. Indeed, one of the major goals of this course
is help familiarize the surgeon with these guiding principles. When implants loosen, critical evaluation of the repair often
reveals that one or more of these principles was violated. Although there are some underlying common principles, a specific
set of guidelines exist for application of pins, wire, plates, screws, and external skeletal fixation.
The bone can fail to heal
In addition to the presence of instability, bone fails to heal when the biologic environment is poor secondary to trauma,
or if the biologic environment has been compromised by the method of repair. Examples include open fractures with devascularized
tissue secondary to trauma, or fractures with avascular and unstable fragments secondary to iatrogenic trauma. In instances
where the biologic environment is insufficient to allow healing, nearly all bone-implant constructs will eventually fail.
In many instances fracture healing can be aided by considering the cause of the injury, the condition of the surrounding soft
tissues, the forces acting at the fracture site, and factors inherent to the patient (age, body status, general health) when
selecting a repair technique. Techniques to promote fracture healing, such as application of a cancellous bone graft, are
often beneficial and are rarely contraindicated.
