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External fixator like pin fixators etc .pptx
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- 2. • External fixationis a method of immobilizing fractures by means of pins passed through the skin and bone. Pin pierces the limb completely or from one side and these pins are joined outside the limb by a rigid scaffolding .. hence the name External fixator. • • • Minimum metal exists inside Fracture elements are at will distracted, or compressed. the tissue realigned, • Wound area is well exposed, local lavage, flushing, dressing and surgical procedures – easy and convenient. Efficient stabilization Facilitates limb elevation Early movts of adjacent joint • • •
- 3. • The historyof external fixation goes back to the ancient times when Hippocrates in about 400 BC wrote about a simple external fixator. Hippocrates described a form of external fixation to splint a fracture of the tibia with the device consisting of closely fitting proximal and distal Egyptian leather rings connected by four wooden rods from a cornel tree. Malgaigne in 1840 has been credited with the first use of “pins” when he created a simple metal pin in a leather strap for the percutaneous pin treatment of a tibial fracture • •
- 4. • Parkhill 1894 Threadedpins and clamp
- 5. Lambotte 1902, selftapping threaded pins, rod, adjustable clamps
- 6. • 1st In 1917.Humphry is the man who uses threaded pins, but he uses only one pin above fracture and one below the fracture site. • In 1948, Charnley popularized his compression device to facilitate arthrodesis of joints. • In 1966 and 1974,Anderson et al. uses transfixing pins incorporated into a plaster cast for series of tibial shaft fractures . management of large
- 7. Aim of application ofExternal Fixator is to achieve an environment conducive to fracture and soft tissue healing Two main types Pin fixators and Ring fixators ,
- 8. PIN FIXATORS Applied quickly Stabilizemost diaphyseal # Adequate wound access – Mx of soft tissue Disadv : # has to be reduced before construction of frame. Presence of a fixed bar, remote from the axis of the bone, limits adjustability of frame to control angulatory and rotatory deformities. Cantilevered System does High incidence of delayed modified or bone grafting not allow axial loading union or non union unless fixator is carried out. is Angular deformities may occur.
- 9. • RING FIXATORS –Used in treatment of problems requiring complex reconstruction These frames replicate structure of long tubular bone like exoskeleton. Bone is stabilized by tensioned wires acting like elastic band Provides sufficient stability for most complicated diaphyseal fractures Multiplane deformity correction can be achieved Excellent for Progressive deformity correction, limb lengthening and Mx of non union – – – – – – – – – – Disadvantages : Heavy, cumbersome Time consuming procedure to plan and construct Poor access to soft tissues Risk of neurovascular damage
- 10. • Components ofPin fixator Bone screws or pins Clamps Connecting rods or tubes Half pin � j j lSteinmann pin
- 11. • Pin –Schanz screw or half pin It has threads at one end and a rounded 3 mm to 6 mm diameter Stabilizing hold on bone segment Does not pass much beyond far cortex tip at the other. Modified cortical screw but the core diameter is slightly larger than the corresponding cortical screw (3.4 mm instead of 3mm for a 4.5mm screw) Torsional and bending strength increases Steinman Pin. Available in 3, 4 and 5mm
- 12. Pin is describedunder 4 heading Tip, Thread, Core and Shaft Tip Triangular tip cuts its own threads in the bone. Pilot hole is drilled before inserting the pin. A variety of pin tips are in use
- 13. • Threads Threads takehold in the bone and provides a secure purchase. Cutting threads initiate bone thread formation; Sizing threads bring this up to the required shape and size. Depending on the length of threaded portion, a pin may have a hold in one or both cortices Short thread engages
- 14. Core Core diameter affectsthe strength of the pin Torsional strength – cube of core diameter Tensile strength – square of core diameter Shaft Strongest part of the pin More rigid then the threaded portion Used to fasten pins to clamps
- 15. • CLAMPS Provides connectionbetween pins components and other Permits multiplanar tube interface Two types Pin to Rod Rod to Rod adjustment of the pin –
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- 17. • UNILATERAL UNIPLANAR Simpleto construct Stiffness in sagittal plane is higher Fewer skin entry holes – less chances of infection, less scars Pins applied in safe corridors Sufficient stability is achieved Reduction has to be done before frame is complete
- 18. • UNILATERAL BIPLANAR Moststable of unilateral frames Used for treatment of tibia # Stable fixation achieved Useful in prolonged application of the fixator in cases of bone loss or open wounds
- 19. • BILATERAL UNIPLANAR Steinmanpin is used In cases of transverse or short oblique # or in osteotomy – axial compression is achieved by preloading the Steinman pin. For long oblique or spiral # - Lag screw might be inserted along with the construct - stability. for Complete elimination of lateral movements Uniform distribution of stresses on the cortices Skin exposed to two possible sources of contamination, double scar mark Used only for lesions of leg and supracondylar region of femur Weaker than unilateral frame in sagittal plane
- 20. • BILATERAL BIPLANAR Indicatedmainly in tibia, occasionally distal femur and rarely elbow, in large bony defects, for arthrodesis of knee and elbow Great torsional stability
- 21. • MODULAR FRAME Modificationof unilateral uniplanar frame. Two pins of one segment are connected to a short tube with a pin – tube clamp. Another tube and a tube to tube clamps are used to connect short tubes in two bone segments. All tubes can be rotated and fixed to reduce the fracture. Used in humerus #, for stabilization of pelvis #, open tibial #
- 22. Modular frames -advantages • • Total pin placement freedom. Increased fracture reduction possibility. • • • Secure fixation. Easy dynarnizati n. Quick pin rernova l. Applicable addition or • in segmental fracture and joint injuries. · • Stable for bone segment transportation.
- 23. • Important factorsaffecting stiffness : Number of pins used more number of pins – more stability 2 pin / segment for tibia and 3 for femur pins closer to # - more rigid more pin to pin distance in a segment – more is the bending stiffness pin angled at 90 degree – increases torsional stiffness Pin diameter 4.5mm 3.5mm 2.5mm to 5.5mm for tibia and femur, for radius ulna and for metacarpals or metatarsals More the diameter – more is the stiffness
- 24. Distance between thebone and the connecting rod Closer the pin clamps can be to the pin – bone interface – more rigid fixation Optimal distance – 4 cms 2 rods increases the stiffness (Instead Stiffness of the connecting rod of 1) Pin clamp interface Slippage of clamp decreases stiffness Periodic tightening
- 25. Number and orientation of sidebars Clamp type Clamp P .in separati . . Sidebar/ bone separatio n distance Type and number Spanon Pin within fracture com onent of pins Bone Bone Pin separation component across fracture
- 26. • Pin –Bone Interface There is a race between increasing load carrying capacity of a healing bone and failure of pin bone interface Stress reducing factors at Pin Bone Pin Large diameter High modulus material Multiple pin cluster Reduced Span Preloading Fixator 2 plane fixation construct Patient Reduced weight bearing interface :
- 27. • Preloading : Preloadis a static force of sufficient magnitude applied an implant to overcome all dynamic and muscular contracture forces and to maintain uninterrupted pin bone contact. Lack of tension – leads to micro motion – leads to pin loosening- Osteoclast initiate bone resorption at periosteal and endosteal surfaces to Radial preloading – best method of preloading, achieved by inserting a pin which is larger in diameter than the pre- drilled hole – a designed misfit Optimal misfit is 0.1 mm. Not more than 0.3mm
- 29. Preseot status • E,..ernalfixator not a 'F.. irst and final' (PDFC) technique in a rure treatment LX ellent short-term stabilizer in open vound, poor soft tissue condition and infection Replaced by definitive implant when situation improves Concentric limb segments poorly tolerate fixator pins: early removal recommended Eccentric limb segments fairly tolerate fixator pins: potential for long term retention B -ilateral uni and biplanar arrangements are seldom used • • • • • • • • Unilateral uni and biplanar constructs are occasionally used Modular frames are practical and preferred r - fa - ce - is - the - w - ea - k l - ink - : deterrent for long term P -in-bone �in - te - tion - ica appl • Pin fixator exceptionally used for segment
- 30. PROF. GABRIEL ABRAMOVITCHILIZAROV (1921-1992)
- 31. History Professor Gavril Abramovich Ilizarovwas born in the Caucasus, in the Soviet Union in 1921. • • He was sent, without much orthopedic training, to look after injured Russian soldiers in Kurgan,Siberia in the 1950s. With no equipment he was confronted with crippling conditions of unhealed, infected, and malaligned fractures. • With the help of the local bicycle shop he devised ring external fixators tensioned like the spokes of a bicycle. this equipment he achieved healing, realignment and lengthening to a degree unheard of elsewhere. With • His Ilizarov apparatus is still used today as one of the distraction osteogenesis methods.
- 32. RING FIXATORS Main components Rings Wires Boltsand buckles Pins Pin clamps : Standard elements used to correct skeletal deformity Secondary Rods Plates Supports Posts Hinges Washer Sockets Bolts Nuts components : necessary for assembly of fixator
- 33. RINGS Flat surface and multipleholes – principal component Provides strong support for the frame, designed to bear high stresses of the tensioned wire Internal diameter of ring measures from 80 to 240 mm Complete set has 12
- 34. • • It has halfring and full rings Full ring has more holes than rings Half ring has 18 to 28 holes – of 8mm diameter two connected half • 4mm apart and are
- 35. • • • Five-eighths ring facilitatesjoint motion Deployed near knee and elbow joint Used in middle of regular frame to provide for soft tissue Weaker than full ring access •
- 36. Half ring with curvedends • It is modified 5/8 ring with ends curved outwards Configuration fits deltoid area of the shoulder • Arches • Used in femoral trochanteric area and shoulder joint Available as 90 and 120 degree •
- 37. Bolts and Nuts • • Usedto fasten various parts together Bolt has hexagonal head of 10 mm and a threaded shaft of 6mmdiameter , pitch is 1mm 10, 16 and 30 mm long Nuts have a diameter of 6mm and comes in 6mm, 5mm and 3mm height 1mm pitch of inside thread Turn of a nut is used as a driving force in Ilizarov 1/4th turn 4 times a day is the rate of distraction – compression • • • • •
- 38. Rods • 6mm thickstainless steel threaded rod is the main connector Four equidistant rods connecting 2 neighbouring rings More bending stiffness in a 4 rod construct Can withstand high axial loading Available in 10 lengths ranging from 60 to 400mm Pitch of the thread is 1mm • • • • •
- 39. • A slottedcannulated has 2x2mm slot extending the length 20 threads acts as a connecting rod and a pulling device rod of • K wires can be attached by locking nuts Partially threaded rods along with telescopic rods provides a more stable assembly. •
- 40. • Connection platesused to reinforce ring fixator Used to construct oval rings for foot and large frames for correction of angulation • • Threaded sockets are used reinforced a threaded rod Hollow and threaded from inside to •
- 41. Supports, Posts andHalf hinges Facilitate creation of construct Placed at any location and fixed at any angle Support and posts bear tremendous load Half hinges have a supporting base with 2 flat surfaces matching 10mm wrench Wire fixation bolts are of 2 types cannulated and slotted
- 42. • Washers fillspace between a part and the ring Thickness ranges from 1.5mm to 4mm • • Wrenches used for constructing frame
- 43. • Two methods Completeframe construction before the surgery or assemble frame piece by piece Ring Position Stationary ring is located on the strongest widest part of the bone – proximal end 5cms distal to the joint Distal supporting ring located at distal and epimetaphysis 3- 5 cms away from joint line Pusher puller ring is movable and is used for distraction – compression, located 3 – 5 cms distal to Fracture/Osteotomy/Non union Reference Ring used as reference, determines the distribution of translating forces,
- 44. • Ring inclinationis perpendicular to the bony segment Space between skin and ring : 3cms • • Closer the ring to the bone fragment, more stable is the fragment during all movements
- 45. Wire and Schanzscrew • • • • • Trocar Tip Bayonet pointed Olive Interupted threaded Full threaded • 1.8mm for adults and 1.5mm for children Wires are inserted atleast 3 cms apart Olive wires prevents side to side shift • •
- 46. • Two wirescrisscrossing at 90 degree has best stability Less angle permits displacement and parallel wires allows free movement •
- 48. Indications… Limb lengthening Deformity Correction. InfectedNon-unions. Congenital Pseudarthrosis. • • • • • Treatment of Joint Contractures e.g. resistant congenital talipes euino varus, post burns contractures, post-traumatic stiffness Fixation of complex fractures • • Bone transport & Osteomyelitis (treatment of missing bone in the limb, due to various causes) Arthrodesis (fusion or joining of two bones across joint) • a
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