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Dr. Armaan Singh
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.
INTRODUCTION
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
OSTEOCHONDRAL INTRAMEMBERANOUS OSSIFICATION OPPOSITIONAL NEW BONE FORMATION OSTEONAL MIGRATION (Creeping Subsitituion)
Type of BONE formed
The TYPE , AMOUNT and LOCATION of bone formed
depends upon----- FRACTURE TYPE GAP CONDITION FIXATION RIGIDITY LOADING BIOLOGICAL ENVIRONMENT
FACTORS EFFECTING
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.
FRACTURE HEALING TYPES
TISSUE DESTRUCTION AND HAEMATOMA
FORMATION
INFLAMATION AND CELLULAR PROLIFERATION
STAGE OF CALLUS FORMATION STAGE OF COSOLIDATION STAGE OF REMODELLING
STAGES OF FRACTURE HEALING
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 REMODELLING
Excess 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 VARIABLESOpen Fractures
Impeding or preventing formation # Hematoma Delaying formation repair tissue Risk of infection
INJURY VARIABLES
Intra articular fracturesIf the alignment & congruity joint surface
is not restoredDelayed healing or non union Joint stiffness
* Segmental fractures* Soft tissue interposition* Damage to the blood supply
AGE NUTRTION HEALING PROCESS NEEDS Energy Proteins & carbohydrates
Patient Variables
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
Cancellous or cortical bones
Bone necrosis
Infection
Tissue Variables
Osteoprosis Osteomalacia Primary malignant bone tumors Metastatic bone tumors Fibrous dysplacia Benign bone tumors Bone cysts Osteogenesis imperfecta Paget’s disease Hyperparathyroidism
Bone disease
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.FixationFacilitate fracture healing byPreventing repeated disruption of Repair tissue
Treatment Variables
MALUNION
DELAYED UNION
NONUNION
COMPLICATIONS OF FRACTURE HEALING
A MALUNITED Fracture is one that has healed with
the fragments in a non anatomical position.
CAUSES1 INACCURATE REDUCTION2 INEFFECTIVE IMMOBILIZATION
MAL UNION
MALUNION can IMPAIR FUCNTION by ABNORMAL JOINT SURFACE ROTATION or ANGULATION OVERRIDING MOVEMENT OF NEIGHBOURING JOINT MAY BE
BLOCKED
MALUNION contd…
ALIGNMENT (MOST IMPORTANT) ROTATION RESTORATION OF NORMAL LENGTH ACTUAL POSITION OF FRAGMENTS (LEAST IMPORTANT)
CHARACTERISTICS FOR ACCEPTABILITY OF
FRACTURE REDUCTION
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.
ANALYSIS OF DEFORMITY
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-- OSTEOPROSIS SOFT TISSUE HOW MUCH FUNCTION CAN BE GAINED
MALUNION contd….
ILIZAROV TECHNIQUE is BEST Simultaneous restoration of
ALIGNMENT
ROTATION
LENGTH
MALUNION contd….
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
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
Delayed Union cont.
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)
Nonunion
Factors contributing to development: Systemic Local
Delayed/Nonunion
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
Delayed/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)
Nonunion cont.
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.)
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)
Nonunion cont.
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.)
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
Nonunion cont.
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.
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
Nonunion cont.
CRITERTIA FOR SUCCESSFUL
BONE GRAFT
OSTEOCONDUCTION
OSTEOGENICITY
OSTEOINDUCTION
BONE GRAFTING contd….
Dual onlay
Nonunion of tibial shaft treated by dual onlay grafts
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.)
Stabilization of bone fragments: Internal fixation (hypertrophic #): intamedullary, or
plates and screws External fixation(defects associated#): ie Ilizarov
Nonunion cont.
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.
Factors complicating nonunion Infection Poor tissue quality Short periarticular fragments Significant deformity
Nonunion cont.
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
Specific Bones Metatarsals Tibia Fibula Patella Femur Pelvis and acetabulum Clavicle Humerus Radius Ulna
Nonunion cont.
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