Ortopedická klinika UK.2.LF a FN Motol

- Dětská a dospělá ortopedie a

traumatologie

Ostheosynthesis

Fracture healing

Inflammatory response 

Reparative response 

Remodelling 

Inflammatory response 

Time of injury to 24-72 hours Injured tissues and platelets release vasoactive mediators, growth factors and other cytokines. These cytokines influence cell migration, proliferation, differentiation and matrix synthesis.   Growth factors recruit fibroblasts, mesenchymal cells & osteoprogenitor cells to the fracture site. Macrophages, PMNs & mast cells (48hr) arrive at the fracture site to begin the process of removing the tissue debris.

Important cytokines in bone healing

BMPs Osteoinductive, induces metaplasia of mesenchymal cells into osteoblasts

Target cell for BMP is the undifferentiated perivascular mesenchymal cell

TGF- Induces mesenchymal cells to produce type II collagen and proteoglycans

Induces osteoblasts to produce collagen

PDGF Attracts inflammatory cells to the fracture site

FGF Stimulates fibroblast proliferation

IGF II Stimulates type I collagen production, cartilage matrix synthesis and cellular proliferation

IL 1 Attracts inflammatory cells to the fracture site

IL 6 Attracts inflammatory cells to the fracture site

Reparative response

– 2 days to 2 weeks Vasoactive substances (Nitric Oxide & Endothelial Stimulating Angiogenesis Factor) cause neovascularisation & local vasodilation Undifferentiated mesenchymal cells migrate to the fracture site and have the ability to form cells which in turn form cartilage, bone or fibrous tissue. The fracture haematoma is organised and fibroblasts and chondroblasts appear between the bone ends and cartilage is formed (Type II collagen). The amount of callus formed is inversely proportional to the amount of immobilisation of the fracture. In fractures that are fixed with rigid compression plates there can be primary bone healing with little or no visible callus formation.

Types of callus

External (bridging) callus

From the fracture haematoma Ossifies by endochondral ossification to form woven bone

Internal (medullary) callus

Forms more slowly and occurs later

Periosteal callus Forms directly from the inner periosteal cell layer. Ossifies by intramembranous ossification to form woven bone

Remodelling 

Middle of repair phase up to 7 years Remodelling of the woven bone is dependent on the mechanical forces applied to it (Wolff’s Law - 'form follows function') Fracture healing is complete when there is repopulation of the medullary canal Cortical bone Remodelling occurs by invasion of an osteoclast “cutting cone”

which is then followed by osteoblasts which lay down new lamellar bone (osteon)

Cancellous bone Remodelling occurs on the surface of the trabeculae which causes

the trabeculae to become thicker

Factors influencing bone healing

Local Degree of local trauma

Degree of bone loss

Vascular injury

Type of bone fractured

Degree of immobilisation

Infection

Local pathological condition

Systemic Age,

Hormones (Cortisone Calcitonin TH/PTH GH Androgens)

Functional activity,

Nerve function,

Nutrition,

Drugs (NSAID)  

Fracture managemet

first aid - immobilisation

conservative

operative

Nonoperative

immobilization with casting or splinting made from fiberglass or plaster of Paris (POP).

Closed reduction is needed if the fracture is significant displaced or angulated -the nonoperative technique:is achieved by applying traction to the long axis of the injured limb and then reversing the mechanism of injury/fracture

Traction

Traction

fractures and dislocations that are not able to be treated by castingskin traction, traction tapes attached to the skin of the limb segment below the fracture usually 10% of the patient's body weight is rarely used as definitive therapy in adults;(the traction is maintained until the patient is taken to the operating room for ORIF or hemiarthroplasty in NOF fr.) skeletal traction, a pin (eg, Steinmann pin, KI wires) is placed through a bone distal to the fracture Weights applied to this pin and the patient is placed in an apparatus to facilitate traction and nursing care Skeletal traction is most commonly used in femur fractures: A pin is placed in the distal femur or proximal tibia 1-2 cm posterior to the tibial tuberosity

Sceletal traction

OperativeFailed nonoperative (closed) management Unstable fractures that cannot be adequately maintained in a reduced position Displaced intra-articular fractures (>2 mm) Patients with fractures that are known to heal poorly following nonoperative management (eg, femoral neck fractures) Large avulsion fractures that disrupt the muscle-tendon or ligamentous function of an affected joint (eg, patella, olecranon fracture, ) Impending pathologic fractures Multiple traumatic injuries with fractures involving the pelvis, femur, or vertebrae Unstable open fractures or complicated open fractures Fractures in individuals who are poor candidates for nonoperative management that requires prolonged immobilization (eg, elderly patients with proximal femur fractures) Fractures in growth areas in skeletally immature individuals that have increased risk for growth arrest (eg, Salter-Harris types III-V) Nonunions or malunions that have failed to respond to nonoperative treatment

Surgical therapy

In 1958, the Association for the Study of Internal Fixation (ASIF) OA( Arbeitsgemeinschaft für Osteosynthesefragen) 4 treatment goals

1. Anatomic reduction of the fracture fragments: diaphysis: anatomical alignment assuring length, angulation, and rotation intra-articular fractures: anatomic reduction of all fragments.

2. Stable internal fixation to fulfill biomechanical demands 3. Preservation of blood supply to the injured area of the extremity 4. Active pain-free mobilization of adjacent muscles and joints

Surgical therapy

ORIF - Open reduction and internal fixation

Kirschner wires (K- wires) Plates and screws

Intramedullary nailing

External fixation

Open reduction and internal fixation

exposing the fracture site and obtaining a reduction of the fracture

must be stabilized and maintained

AO principles

System

Fixation elements

Surgical technique

Complications resolving

Manual

New technique

Kirschner wires

commonly used in fractures around joints. resist only changes in alignment, they do not resist rotation and have poor resistance to torque and bending forcesused as adjunctive fixation for screws or plates and screws casting or splinting is used in conjunction. can be placed percutaneouslyadequate for small fragments in metaphyseal and epiphyseal regions, especially in fractures of the distal foot, wrist, and hand, ( Colles fractures, and in displaced metacarpal and phalangeal fractures after closed reduction )

Plates and screws designs vary depending on the anatomic region and size of the boneused in the management of articular fracturesallows early ROM and the use of muscles and jointsstrength and stability, neutralize forces Buttress plates counteract compression and shear - metaphysis and epiphysis used around joints to support intra-articular fracturesCompression plates (DCP – Dinamic commpression plate, LC-DCP low contact dinamic commpression plate) counteract bending, shear, and torsion, eccentrically loaded holes in the plate used in long bones (fibula, radius, and ulna) Neutralization plates combination with interfragmentary screw fixation interfragmentary compression screws provide compression, plate neutralizes torsional, bending, and shear forces ( lag screws increases the stability of the construct) (fibula, radius and ulna, and humerus)Bridge plates - management of multifragmented diaphyseal and metaphyseal fractures.

Contraindications of ORIF

Active infection (local or systemic) or osteomyelitis Osteoporotic bone that is too weak to sustain internal or external fixation Soft tissues overlying the fracture or surgical approach that are poor in quality due to burns, surgical scars, or infection (In such scenarios, soft tissue coverage is recommended.) Medical conditions that contraindicate surgery or anesthesia (eg, recent myocardial infarction) Cases in which amputation would better serve the limb and the patient

Intramedullary nailingwidely acceptedoperate like an internal splint allows for compressive forces at the fracture site, which stimulates bone healing minimally invasive proceduresfemoral shaft fr. UFN,tibial shaft fr. UTN; humeral shaft fr. UHN. ESIN Elastic stabilization intramedullary nailing TEN –titanium elastic nail

Intramedullary nails: 1. flexible or rigid, 2. locked (maintain alignment and

length, and limit rotation) or unlocked,

3. reamed or unreamed,

Complications surgical management

Neurologic and vascular injury

Compartment syndrome

Infection

Thromboembolic events

Avascular necrosis

Posttraumatic arthritis

Neurologic and vascular injury

nerve injury - patient experiences motor or sensory deficiencies

Arterial injury - pulses are diminished or absent - immediate realignment, angiography is indicated - vascular surgeons (knee dislocations, proximal tibial fractures, and supracondylar humerus fractures)

Compartment syndrome

reported by von Volkmann in 1872, potentially limb-threatening condition, tissue pressure exceeds perfusion pressure in a closed anatomic space ( hand, forearm, upper arm, most commonly occurs in the anterior compartment of the leg) involves tissue necrosis; functional limb impairment; renal failure secondary to rhabdomyolysis, which may lead to deathoccur after traumatic injury, after ischemia (eg, after hemorrhage or thromboembolic event); and in rare cases, with exerciseClinically: pain out of proportion to the degree of injury, pain with passive stretch of the involved muscles, pallor, paresthesia, pulselessness is a late finding can be measured greater 30 mm Hg indicates surgical fasciotomy of the affected compartments.

Infection

local infection: cellulitis, osteomyelitis, systemic infection, sepsisEarly recognition prevents the development of sepsisThe most common pathogen is Staphylococcus aureus, group A streptococci, coagulase-negative staphylococci, enterococciATB should be administered if an infection is suspected,lab: C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) If infection cannot be eradicated with antibiotics, I&D of the surgical wound may be necessary, with removal of the hardware, but only if it is not performing its role.

Thromboembolic events

may occur after trauma with prolonged immobilizationimmobile for 10 or more days have a 67% incidence of thrombosis (Canale, 1998)prophylaxis is effective in decreasing the incidence of deep vein thrombosis, but it has not been shown to be effective in decreasing the incidence of fatal pulmonary embolism.Prophylactic anticoagulation LMWH, Warfarin, early mobilization

Avascular necrosis

disruption of blood supply to a region of bonecan lead to nonunion, bone collapse, or degenerative changesassociated with NOF # and femoral head #, scaphoid, talar neck and body, and proximal humerus.

Posttraumatic arthritis

common in intra-articular fractures

fractures that are not adequately reduced

management: arthroscopic debridement, osteotomy, arthroplasty, or arthrodesis

External fixation

In 1907 in Alvin Lambotte, 1952 Ilizarevprovides stabilization at a distance from the fracture site without interfering with the soft tissue structuresmaintains length, alignment, and rotation without requiring castingallows inspectiontypes: Wagner, Orthofix, Unifix,

Indications Open fractures with significant soft tissue disruption (eg, type II or III open fractures) Soft tissue injury (eg, burns) Pelvic fractures (temporarily) Severely comminuted and unstable fractures Fractures that are associated with bony deficits Limb-lengthening proceduresFractures associated with infection or nonunion arthrodesis

Complications of external fixation

pin tract infection,

pin loosening or breakage,

interference with joint motion,

neurovascular damage when placing pins,

malalignment caused by poor placement of the fixator,

delayed union and malunion

Spetial types of osteosynthesis

LISS ( less invasive stabilisation system) implants for MIPPO (minimal invasive percutane plate osteosynthesis) -Herbert´s screw – scafoid #DHS – NOF# basicervicalPFN – NOF # pertrochanteric Phillos –prox. humerusDCS (dinamic condylar screw) and DFN (distal femoral nail) - dist. femurPilon plate – dist. tibia