Bone healing by Dr. Bipul Borthakur

1. DR.BIPUL BORTHAKUR(PROFESSOR)
DEPT OF ORTHOPAEDICS, SMCH

2.  Fracture healing is a complex process that requires
the recruitment of appropriate cell and the
subsequent expression of the appropriate genes at
the right time and in the right anatomic location.
 A fracture initiates a sequence of inflammation, repair,
and remodelling that can restore the injured bone to its
original state within a few months if each stage of this
complex interdependent cascade proceeds undisturbed.

3.  CELLS
 Inflammatory cells
 Progenitor cells
 Chondrocytes
 Osteoblast
 Osteoclast
 Muscle cells
 Scaffold
 Hematoma
 Collagen
 Noncollagenous proteins
 Blood Supply
 Blood vessels
Supporting cells (pericytes)
 Molecules
Matrix-embedded proteins
Locally produced factors
 Systemic hormones

4.  A.Endochondral: The process whereby a
cartilaginous anlage is replaced by bone is referred
to as endochondral ossification.
 B. Intramembranous:The process of direct bone
formation without a cartilaginous intermediate is
referred to as intramembranous ossification.

5. 1. Hematoma Formation
2. Inflammation
3. Soft Callus
4. Hard Callus
5. Remodeling

7.  Described by Einhorn.
 Characterized them by location:
I. bone marrow
II. cortex
III. periosteum
IV. external soft tissues

8.  Uhthoff listed a number of systemic and local
factors that affect fracture healing.
 Classified them as being present at the time of
injury, caused by the injury, dependent on
treatment, or associated with complications.

10.  Failures of healing fall into two broad categories with
associated cellular mechanisms: Biologic and
mechanical failures.
 Atrophic nonunion is defined by the absence of any
visible bone formation on radiographs.
 Hypertrophic nonunion is defined by abundant bone
formation without bone bridging the fracture site.
 Oligotrophic nonunion is defined as failure to bridge
the fracture site with only a moderate amount of bone
formation adjacent to a visible fracture line.
 Delayed union represents the situation where
healing is prolonged compared to that expected for a
given anatomic location.

11.  Atrophic Nonunion:The major factors that
contribute to atrophic nonunions include,
infection, compromised nutrition, smoking,
medications, and surgeon-controlled factors
such as fracture vascularity.
 Hypertrophic Nonunion:The development of a
hypertrophic nonunion is generally related to
a lack of adequate stability at the fracture site

13.  AUTOLOGOUS BONE GRAFTS:Autologous
bone grafts contain the three required
components for the formation of bone:
osteoconduction, osteoinduction and cellular
osteogenesis.
 The harvest of femoral bone marrow using
the techniques of femoral nailing and a
specialized reamer/irrigator/aspirator (RIA)
(Synthes) is a more recent method for
obtaining significant amounts of marrow
from the femur.

14.  Autologous Cancellous Bone Graft:
 Cancellous bone is the most commonly used bone-graft
source,serving as an effective graft material for fractures that
do not require immediate structural support from the graft.
Instead,it serves as a scaffold for the attachment of host cells
and itprovides the osteoconductive and osteoinductive
functionsrequired for the laying down of new bone.
 Autologous Cortical Bone Graft:
 Its use is indicated when immediate structural support is
necessary,but it has slightly limited long-term healing
potential

16.  ALLOGRAFT-BASED BONE GRAFT
SUBSTITUTES:Allograft comes in many forms
and is prepared in many ways,including
freeze-dried, irradiated (electron beam and
gammaray), and decalcified.

17.  Presently, only two proteins have been
isolated, produced, and approved for use in
humans. Because they are produced by the
recombinant process, they are designated
rhBMP-2 and rhBMP-7
 Other BMPs that have been shown to have
osteogenic properties are BMP-4, -6, and -9

18.  the most frequently used cell-based graft is
autologous bone marrow.

19.  Ceramic and collagen bone substitutes can
provide osteoconduction without the risk of
disease transmission.
 Available ceramics include calcium sulfate,
calcium phosphate, and bioactive glass.

20.  Polymers available for bone graft substitutes
include both natural and synthetic polymers,
biodegradable and nonbiodegradable.
 Biodegradable natural and synthetic materials
include polyglycolic acid and poly(lacticco-
glycolic) acid

21.  Coralline hydroxyapatite is one of the first
substances used as a bone substitute.
 Chitosan and sponge skeleton are other
potential graft substitutes.

22.  The mechanical environment has a direct
impact on fracture healing.
 Direct mechanical perturbation and
biophysical modalities such as electrical and
ultrasound stimulation have been shown to
affect fracture healing.

23.  Electrical potentials were first described in
mechanically loaded bone by Fukada and Yasuda
in 1957.
 There are currently three methods for the
electrical stimulation of bone healing:
(i) constant direct current (DC) stimulation with the
use of percutaneous or implanted electrodes
(invasive)
(ii) capacitive coupling (noninvasive)
(iii) time-varying inductive coupling produced by a
magnetic field (noninvasive; also known as PEMF
stimulation).

24.  Although animal and clinical studies have
confirmed the ability of ultrasound to
enhance fracture healing, the exactphysical
mechanism has not been established.
 Low-intensity ultrasound has been shown to
increase the incorporation of calcium ions in
cultures of cartilage and bone cells and to
stimulate the expression of numerous genes
involved in the healing process, including IGF
and TGF-β.

25.  Extracorporeal shock wave therapy (ESWT)
involves the productionsingle high amplitude
sound waves producing tensionand forces on
a focused area.
 This stimulates bone formation by increasing
local and systemic inflammatory and
osteogenic growth factors.