FRACTURE HEALING

Dr. NISHITH SHARMADEPT. OF ORTHOPAEDICS

NIMS MEDICAL COLLEGE & HOSPITAL

INTRODUCTION

• Fracture is a break in the structural continuity of bone or periosteum.

• The healing of fracture is in many ways similiar to the healing in soft tissue wounds except that the end result is mineralised mesenchymal tissue i.e. BONE.

• Fracture healing starts as soon as bone breaks and continues modelling for many years.

The essential event in fracture healing is the creation of a bony bridge between the two fragments which can be readily be built upon and modified to suit the particular functional demands .

Components of BONE Formation

Cortex

Periosteum

Bone marrow

Soft tissue

Type of BONE formed

OSTEOCHONDRAL INTRAMEMBERANOUS OSSIFICATION OPPOSITIONAL NEW BONE FORMATIONOSTEONAL MIGRATION (Creeping Subsitituion)

FACTORS EFFECTING

The TYPE , AMOUNT and LOCATION of bone formed depends upon-----

FRACTURE TYPE GAP CONDITION FIXATION RIGIDITY LOADING BIOLOGICAL ENVIRONMENT

FRACTURE HEALING TYPES

Fracture healing is divided according to bone--

1. Cortical bone of the shaft.

2. Cancellous bone of the metaphyseal region of the long bones and the small bones.

STAGES OF FRACTURE HEALING

TISSUE DESTRUCTION AND HAEMATOMA FORMATION

INFLAMATION AND CELLULAR PROLIFERATION

STAGE OF CALLUS FORMATION STAGE OF COSOLIDATION STAGE OF REMODELLING

Tissue destruction and Hematoma formation

– Torn blood vessels hemorrhage

– A mass of clotted blood (hematoma) forms at the fracture site

– Site becomes swollen, painful, and inflamed

Tissue destruction and Hematoma formation

INFLAMATION AND CELLULAR PROLIFERATION

• Within 8 hours inflammatory reaction starts.

• Proliferation and Differntiation of mesenchymal stem cells.

• Secretion of TGF-B , PDGF and various BMP factors.

Callus Formation

• Fibrocartilaginous callus forms

• Granulation tissue (soft callus) forms a few days after the fracture

• Capillaries grow into the tissue and phagocytic cells begin cleaning debris

Callus Formation Theory

• OSTEOPROGENITOR CELL present in all ENDOSTEAL and SUBPERIOSTEAL surface give rise to CALLUS.

• CALLUS arises from NON-SPECIALISED CONNECTIVE TISSUE CELLS in the region of fracture which are induced into conversion to OSTEOBLASTS.

Callus Formation

STAGE OF CONSOLIDATION

– New bone trabeculae appear in the fibrocartilaginous callus

– Fibrocartilaginous callus converts into a bony (hard) callus

– Bone callus begins 3-4 weeks after injury, and continues until firm union is formed 2-3 months later

STAGE OF REMODELLINGExcess material on the

bone shaft exterior and in the medullary canal is removed

Compact bone is laid down to reconstruct shaft walls

Schematic drawing of the callus healing process. Early intramembranous bone formation (a), growing callus volume and diameter mainly by enchondral ossification (b), and bridging of the fragments (c).

Figure from Brighton, et al, JBJS-A, 1991

A: Roentgenogram of a callus healing in a sheep tibia with the osteotomy line still visible (6 weeks p.o.). B: Histological picture of a sheep tibia osteotomy (fracture model) after bone bridging by external and intramedullary callus formation. A few areas of fibrocartilage remain at the level of the former fracture line (dark areas).

Variables Influence Fracture Healing

INJURY VARIABLES

Open FracturesImpeding or preventing formation # Hematoma Delaying formation repair tissue Risk of infection

INJURY VARIABLES

Intra articular fractures

If the alignment & congruity joint surface is not restored

Delayed healing or non union Joint stiffness

* Segmental fractures* Soft tissue interposition* Damage to the blood supply

Patient Variables

AGENUTRTION HEALING PROCESS NEEDS Energy Proteins & carbohydrates

Patient Variables cont…. Systemic hormones Corticosteroid ( ) Growth hormone Thyroid hormone Calcitonin Insulin Anabolic steroids DM Hypervitaminosis D Rickets

Inhibit fracture healing ( Vascularization?)Nicotine

Rate fracture healing

Rate fracture healing

Tissue Variables

Cancellous or cortical bones

Bone necrosis

Infection

Bone disease

Osteoprosis Osteomalacia Primary malignant bone tumors Metastatic bone tumors Fibrous dysplacia Benign bone tumors Bone cysts Osteogenesis imperfecta Paget’s disease Hyperparathyroidism

Treatment Variables

Apposition of fracture fragments Loading & micromotion Loading a fracture site stimulates bone

formation Micromotion promotes fracture healing

Treatment Variables

Fracture stabilization Traction Cast Imm Ext.Fixation Int.Fixation

Facilitate fracture healing byPreventing repeated disruption of Repair tissue

COMPLICATIONS OF FRACTURE HEALING

• MALUNION

• DELAYED UNION

• NONUNION

MAL UNION

A MALUNITED Fracture is one that has healed with the fragments in a non anatomical position.

CAUSES1 INACCURATE REDUCTION2 INEFFECTIVE IMMOBILIZATION

MALUNION contd…

MALUNION can IMPAIR FUCNTION byABNORMAL JOINT SURFACEROTATION or ANGULATIONOVERRIDINGMOVEMENT OF NEIGHBOURING JOINT MAY

BE BLOCKED

CHARACTERISTICS FOR ACCEPTABILITY OF FRACTURE REDUCTION

ALIGNMENT (MOST IMPORTANT) ROTATION RESTORATION OF NORMAL LENGTHACTUAL POSITION OF FRAGMENTS (LEAST IMPORTANT)

ANALYSIS OF DEFORMITY

• RIES and O’NEILL developed TRIGNOMETRIC ANALYSIS of DEFORMITY and designed E-GRAPH to determine the true maximal deformity on AP and LATERAL X-Ray views.

MALUNION contd….

• Operative treatment for most malunited fracture should not be considered until 6 to 12 months but in INTRA ARTICULAR fracture early operative treatment is needed.

• Surgeon should look for before surgery--OSTEOPROSISSOFT TISSUE HOW MUCH FUNCTION CAN BE GAINED

MALUNION contd….

ILIZAROV TECHNIQUE is BEST Simultaneous restoration of

ALIGNMENT

ROTATION

LENGTH

Delayed Union

• The exact time when a given fracture should be united cannot be defined

• Union is delayed when healing has not advanced at the average rate for the location and type of fracture (Btn 3-6 mths)

• Treatment usually is by an efficient cast that allows as much function as possible can be continued for 4 to 12 additional weeks

Delayed Union cont.

• If still nonunited a decision should be made to treat the fracture as nonunion

• External ultrasound or electrical stimulation may be considered

• Surgical treatment should be carried out to remove interposed soft tissues and to oppose widely separated fragments

• Iliac grafts should be used if plates and screws are placed but grafts are not usually needed when using intramedullary nailing, unless reduction is done open

Nonunion

• FDA defined nonunion as “established when a minimum of 9 months has elapsed since fracture with no visible progressive signs of healing for 3 months”

• Every fracture has its own timetable (ie long bone shaft fracture 6 months, femoral neck fracture 3 months)

Delayed/Nonunion

Factors contributing to development:• Systemic• Local

Delayed/Nonunion cont.

Systemic factors:• Metabolic• Nutritional status• General health• Activity level• Tobacco and alcohol use

Delayed/Nonunion cont.

Local factors• Open• Infected• Segmental (impaired blood supply)• Comminuted• Insecurely fixed• Immobilized for an insufficient time• Treated by ill-advised open reduction• Distracted by (traction/plate and screws)• Irradiated bone• Delayed weight-bearing > 6 weeks• Soft tissue injury > method of initial treatment

Nonunion cont.

Nonunited fractures form two types of pseudoarthrosis:

• Hypervascular or hypertrophic• Avascular or atrophic

Nonunion cont.

Hypervascular or Hypertrophic:

1. Elephant foot (hypertophic, rich in callus)

2. Horse foot (mildly hypertophic, poor in callus)

3. Oligotrophic (not hypertrophic, no callus)

Hypervascular nonunions. A, "Elephant foot" nonunion. B, "Horse hoof" nonunion. C, Oligotrophic nonunion (see text). (Redrawn from Weber BG, Cech O, eds: Pseudarthrosis, Bern, Switzerland, 1976, Hans Huber.)

Nonunion cont.

Vascular or Atrophic• Torsion wedge

(intermediate fragment)• Comminuted (necrotic

intermediate fragment)• Defect (loss of fragment

of the diathesis)• Atrophic (scar tissue

with no estrogenic potential is replacing the missing fragment)

Avascular nonunions. A, Torsion wedge nonunion. B, Comminuted nonunion. C, Defect nonunion. D, Atrophic nonunion (see text). (Redrawn from Weber BG, Cech O, eds: Pseudarthrosis, Bern, Switzerland, 1976, Hans Huber.)

Nonunion cont.

Classification (Paley et al)• Type A<2cm of bone loss A1 (Mobile deformity) A2 (fixed deformity) A2-1 stiff w/o

deformity A2-2 stiff w/ fixed

deformity• Type B>2cm of bone loss B1 with bony defect B2 loss of bone length B3 both

A, Type A nonunions (less than 1 cm of bone loss): A1, lax (mobile); A2, stiff (nonmobile) (not shown); A2-1, no deformity; A2-2, fixed deformity. B, Type B nonunions (more than 1 cm of bone loss): B1, bony defect, no shortening; B2, shortening, no bony defect; B3, bony defect and shortening.

Nonunion cont.

Treatment:1. Elecrical2. Electromagnatic3. Ulrasound4. External fixation (ie deformity, infection, bone loss)5. Surgical

• Hypertrophic: stable fixation of fragments• Atrophic: decortication and bone grafting• According to classification: type A : restoration of alignment, compression type B : cortical osteotomy, bone transport or lengthening

Nonunion cont.

Surgical guidelines:• Good reduction• Bone grafting• Firm stabilization

Nonunion cont.

Reduction of the fragments:• Extensive dissection is undesirable, leaving

periosteum, callus, and fibrous tissue to preserve vascularity and stability, resecting only the scar tissue and the rounded ends of the bones

• External fixator, Intramedullary nailing, Ilizarov frame

Nonunion cont.

Bone Grafting origins:• Autogenous “the golden standard”• Allograft• Synthetic substitute

Nonunion cont.

Bone grafting techniques:• Onlay• Dual onlay• Cancellous insert• Massive sliding graft• Whole fibular transplant• Vascularized free fibular graft• Intamedullary fibular graft

BONE GRAFTING contd….

CRITERTIA FOR SUCCESSFUL BONE GRAFT

• OSTEOCONDUCTION

• OSTEOGENICITY

• OSTEOINDUCTION

• Nonunion of tibial shaft treated by dual onlay grafts

Dual onlay

Massive sliding graft

GILL MASSIVE SLIDING GRAFT

Whole fibular transplant• Bridging of bone defect

with whole fibular transplant. A, Defect in radius was caused by shotgun wound. B and C, Ten months after defect was spanned by whole fibular transplant, patient had 25% range of motion in wrist, 50% pronation and supination, and 80% use of fingers.

Vascularized free fibular graft• Posteroanterior

and lateral roentgenograms made 3 years after fibular transfer, showing excellent remodeling with fracture healing. (From Duffy GP, Wood MB, Rock MG, Sim FH: J Bone Joint Surg 82A:544, 2000

Intamedullary fibular graft• Anteroposterior

roentgenogram of humerus 5 months after insertion of fibular allograft and compression plating with a 4.5-mm dynamic compression plate revealing evidence of bridging callus formation and incorporation of the allograft. (From Crosby LA, Norris BL, Dao KD, McGuire MH: Am J Orthop 29:45, 2000.)

Nonunion cont.

Stabilization of bone fragments:• Internal fixation (hypertrophic #):

intamedullary, or plates and screws• External fixation(defects associated#): ie Ilizarov

Internal fixation

• Roentgenograms of patient with subtrochanteric nonunion for 22 years treated with locked second generation femoral nail. A, Preoperatively. B, Postoperatively.

Ilizarov

Bifocal osteosynthesis with Ilizarov fixator after debridement of necrotic segments, as recommended by Catagni.

Monofocal osteosynthesis with Ilizarov fixator for hypertrophic nonunions with minimal infection, as recommended by

Catagni

Ilizarov cont.

Type IIIB open tibial fracture in 30-year-old man struck by automobile. Initial treatment was with four-pin anterior half-pin external fixator that was later converted to six-pin fixator; this fixator was removed because of persistent infection. B, One year after injury, infected nonunion with deformity. C, Shape of tibial deformity is duplicated by Ilizarov frame and is gradually corrected as nonunion is compressed. D, Union obtained at 4½ months.

Nonunion cont.

Factors complicating nonunion• Infection• Poor tissue quality• Short periarticular fragments• Significant deformity

Infection management

Treatment of nonunion of tibia in which sequestration or gross infection is present. A, Bone is approached anteriorly and is saucerized, incision is closed, and infection is treated with antibiotics by irrigation and suction. B and C, Tibia is grafted posteriorly. B, Skin incision. C, Tibia and fibula have both been approached posterolaterally. Posterior aspect of tibia (or tibia and fibula) is roughened and grafted with autogenous iliac bone

Nonunion cont.

Specific Bones • Metatarsals• Tibia• Fibula• Patella• Femur• Pelvis and acetabulum• Clavicle• Humerus• Radius• Ulna

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