Although great advances have been made in fracture care, treatment failures
are not uncommon. High-energy injuries that result in bone devitalization, or
open fractures that are associated with bone loss, can be followed by
postoperative infection or, if treated with inadequate methods, may result in
the development of a pseudarthrosis. These complex problems require much care
before healing can occur. Since the development and use of stainless steel in
orthopaedics in the 1920s, surgeons have tried to use advances in metallurgy
and implant design to assist fracture-healing. Nails were improved with
locking technology, while simple plates were transformed into blade plates,
compression plates, and now locking plates. External fixation was
revolutionized by G. Ilizarov with the development of distraction
osteogenesis. Stainless steel itself was altered to create vanadium,
Vitallium, and now titanium alloys. While all of these techniques have
decreased the rate of nonunion, they have not completely solved the problem
because there are limits to what metal can do to affect the biology of
fracture-healing.
Although the biologic approach to fracture-healing seems intuitive,
surgeons have had limited options for decades. An ideal bone-graft substitute
must provide scaffolding for osteoconduction, growth factors for
osteoinduction, and progenitor cells for osteogenesis. Autologous
bone-grafting was described by Fred Albee in
19151. Bone-grafting
requires additional surgery, can be painful, and is not without complications.
Although Albee also described the use of calcium phosphates as an alternative
to bone in the 1920s, it was not until 1965, when Marshall Urist identified
"bone formation by
autoinduction"2,
that new options unfolded. Twenty-three years later, Wozney et
al.3 and Luyten et
al.4 discovered the
proteins responsible for this phenomenon, BMPs-2, 3, and 4. Today these
proteins can be harvested from a variety of bone sources or synthesized
through recombinant gene therapy, and they are available to the practicing
orthopaedist.
There has been an explosion of commercial products for the orthopaedic
surgeon to choose from. Calcium phosphate ceramics, calcium sulfate, bioactive
glass, biodegradable polymers, and recombinant human BMPs (OP-1 and BMP-2) are
all offered as solutions to the problem of bone-healing. While the actions of
each product can be confusing, suggested combination therapy can be simply
baffling, especially when there are few objective scientific data. Hospital
administrators are equally perplexed, particularly by the costs of these
products, and in many cases they refuse to allow the surgeon to use them even
though they are thought to be useful.
This issue is of critical importance to the orthopaedic surgeon involved in
fracture care and treatment of nonunions. As the leaders in fracture care in
North America, the Orthopaedic Trauma Association has responded by charging a
committee under the leadership of Dr. William De Long to generate a white
paper to more clearly identify the issues surrounding these products and their
use. This initial report was expanded into the Current Concepts
Review5 in this
issue of The Journal to offer the information to the general
orthopaedic community. It is hoped that, after reading this review, surgeons
will be better able to make decisions based on sound scientific principles and
to understand the limitations as well as the benefits of these commercially
available bone-graft substitutes. In the end, it is the responsibility of the
physician to prescribe the correct treatment for the patient, and that
decision must be made on the basis of fact, not fiction.