ortho instrument

39Instruments and Implants

INSTRUMENTS

Periosteum ElevatorUsed to elevate the periosteumElevation of periosteum is required in all operations on thebone because all the important structure such as vessels,nerves, tendons are outside the periosteumSo, once the periosteum is elevated the surgeon is in a safeplaneAll the muscles are attached to the periosteum, so onceperiosteum is elevated even the muscles are elevatedElevation of periosteum is not done in case of excision ofosteochondroma, this prevents recurrence.

Fig. 39.1: Periosteum elevator


Bone LeverIt is used to lever out (lift) a bone from the depth of a woundafter the periosteum is elevatedIt is placed between the bone and the periosteum, and thusretracts the soft tissue

Fig. 39.2: Bone lever

Bone NibblerThey are used for nibbling of the bone that is to remove asmall piece of bone.

Fig. 39.3: Bone nibbler: angled

530 Best Aid to Orthopedics

Fig. 39.4: Bone nibbler: straight

Some common bone nibblers are:1. Curved nibbler—For spinal surgeries2. Straight nibbler—For general use3. Double action nibbler—They are superior.

Bone CutterIt is used for cutting a bone into small piecesUsually used in bone graftingIt is also available with straight or curved ends and with doubleaction type

Fig. 39.5: Bone cutter


OsteotomeIt is used for cutting of bone (osteotomy)Both the edges are bevelledCommonly used in the following osteotomies:1. Mc Murray’s osteotomy for fracture neck femur2. Corrective osteotomies for Genu varus and Genu valgum

Fig. 39.6: Osteotome

Bone ChiselIt is similar to osteotome except that only one of its surface isbevelled

Fig. 39.7: Bone chisel


It is used for:1. Removing of protruding bone2. Leveling a bone surface, e.g. for leveling excessive callus,

removing an osteochondroma.

MalletIs used for hammering osteotome and chisel.

Fig. 39.8: Mallet

Bone Curette

Uses:Used for curetting a cavity in the boneUsed for removal of fibrous tissue from the fracture ends of anold fracture.

Fig. 39.9: Bone curette


Curettage is performed for:Benign tumors such as enchondroma, giant cell tumorInfections such as tubercular cavity of bone, osteomyelitis.

Bone GougeThis is a concave-bladed chisel.

Uses:Cutting on a round boneMaking round hole in the bone.

Bone awlThis is a pointed instrument; there is an eye at the tip to thread awire through the bone

Uses:Making holes in the boneTendon attachment

Fig. 39.10: Bone awl

Bone Holding ForcepsThere are three types of forceps used for holding the bone


They are:1. Lane’s forceps: For holding femur, tibia2. Lion toothed forceps3. Self-retaining –AO forceps.

Fig. 39.11: Bone holding forceps

Plate Holding ForcepsAfter the reduction is achieved, a plate of suitable size is placedover the fracture and held with the help of this instrument.

Fig. 39.12: Plate holding forceps


These are of 2 types:Lowman’s forcepsAO type self-retaining forceps

Gigle SawA Gigle saw is a flexible wire saw used for bone cutting.

Fig. 39.13: Gigle saw

Ilizarov’s ApparatusThe device is a specialized form ofExternal fixator, a Circular fixator. Stainlesssteel rings are fixed to the bone using Kwires. For more information refer the topicIlizarov’s technique.

Sequestrum forceps: Used for removal ofsequestrum

Medical TourniquetThis can be inflated automaticallyIt is used to control bleeding aftertrauma or during surgery

Fig. 39.14: Ilizarov’sapparatus


Fig. 39.15: Sequestrum forceps

Fig. 39.16: Medical tourniquet

It is usually applied to the proximal portion of the limbComplication: nerve palsies if applied for too long.

Hand DrillUsed to drill bone manually, other two varieties of bone drill areelectric drill and pneumatic drill.

External fixatorUsed in the treatment of compound fractures.

Hexagonal screw driversUsed to tighten the screw while fixing the plate.


Fig. 39.17: Hand drill

Fig. 39.18: AO external fixator with schantz pins and clamps

Fig. 39.19: Hexagonal screw drivers


Fig. 39.20: Plaster of Paris (refer chapter treatmentof fracture: general principles)

SS wireIs used for internal fixation.

Fig. 39.21: SS wire

TRACTION INSTRUMENTS

Kirschner wireThis is a thin straight stainless steel wire.

Uses:For internal fixation of small bonesFor giving tractionTo fix fractures in childrenUsed in Ilizarov’s fixation system.


Fig. 39.22: Kirschner wire

Steinmann pinThis is a stout, stainless steel rod, of diameter ranging from3 to 6 mm

Use: Used for skeletal traction—common sites being upper endof tibia, supracondylar region of femur and calcaneum.

Bohler’s Stirrup

UsesUsed for holding a Steinmann pin and applying traction.The screws on the side of the stirrup are used for holdingthe pin.

K-wire stirrup and tensionerWhen K wire is used to produce skeletal traction, the strength ofthe wire can be increased by subjecting it to an axial tension bythe tensioner.


Skull traction tongsFor examples, Crutchfield tongs and Blackburn tongsUses: In case of cervical injury or diseases.

IMPLANTS

Kuntscher’s cloverleaf intramedullary nailKuntscher, a German surgeon devised the intramedullary nailfor the internal fixation of the femoral fractureNail is a hollow tube with a slot on one sideIt has a clover shape on cross sectionClover leaf shape gives rotational stability to the fractureIt has eye at its either end onto which hook of the extractor isintroduced while removing the nail.

Determination of the size of K-nailLength is measured from the tip of greater trochanter to lateraljoint line of knee and then subtract 2 cm from this

Fig. 39.23: Bohler’s stirrup with Steinmann pin


Diameter of the K nail is determined by the diameter of themarrow at the level of isthmus.

Introduction of the nail can be done in two waysRetrograde: Introduction is from the fracture site → hammeredout proximal so that it comes out of greater trochanter →fracture is reduced → nail is driven into distal fragmentNail is introduced through the greater trochanter guidedthrough a guided wire to fracture site and as K nail comes outthrough the fracture site, guide wire is removed and fracture isreduced under supervision and the nail is driven home• About 2 cm of the nail is left protruding at the trochanter to

facilitate its removal after 2 years, an extractor is introducedinto the eye of the K nail and then removed.

Complications of K nailingNail gets stuckSplintering of cortex while hammering the nailProximal migration of the nail, causing bursitis in the protrudingpartDistal migration of the nail causing stiffness of the kneeInfection

Fig. 39.24: K nail


Smith-Petersen nail (SP nail)SP nail is a cannulated triflanged nailIt is an implant used for internal fixation of fracture neck offemurThe advantages of the triflanged nail are:– It prevents axial rotation of the fragments– It cuts only a little bone to provide good stability– It can be used along with McLaughlin’s plate for the fixation

of intertrochanteric fracture.

Fig. 39.25: SP nail

Dynamic hip screws (DHS)It has two components –The lag screw and the barrelThe lag screw slides freely inside the barrel, so that if there isa collapse at the fracture site, the screw does not cut out ofthe cortex, it telescopes into the barrelUses: Used for the internal fixation of the trochanteric fracture

Fig. 39.26: DHS


PLATES AND SCREWSThese are used to fix 2 bony fragmentsDifferent types of the plates are:1. Heavy duty broad2. Narrow platesScrews may be used alone or in combination with the plateIn the past machine screws (self-tapping) screws were used,but now nontapping screws are used (AO screws)Nontapping screws are better than self-tapping screws,because in the self-tapping screw, while tightening, heat isproduced at the bone screw interface causing necrosis ofborn and thus loosening of the screwsFor a nontapping screw, threads are cut in the bone with aspecial instrument called bone tap.

Fig. 39.27: Reconstruction plate, DCP narrow 3.5 mm, DCP heavy duty4.5 mm, DCP broad,

DCP =dynamic compression plate


Fig. 39.29: Interference screw, locking bolt for nail, cortical screw,cancellous screw, malleolar screw, canulated cancellous screw

Fig. 39.28: (Left to Right) Lock compression plate for upper humerus,one-third tubular plate, T plate for distal radius, Ellis plate


PROSTHESIS

Austin-Moore prosthesisUsed for the replacement of femoralhead in case of fracture neck of thefemur in elderly personIt is available in odd number sizesfrom 35 to 59 mmThere is a small hole in the top of thestem for the hook of the extractorused while removing the prosthesisThe stem has two fenestrations inthe middle, through which bonesupposedly grows and helps infixation of the prosthesisThis prosthesis can thus be usedonly without cement because the useof cement would make its removal ifrequired, difficult.

Thompson prosthesisThis is prosthesis for the head ofthe femur, similar to Austin-MooreprosthesisIt is especially indicated in caseswhere the neck of the femur isabsorbed, e.g. in old fractures of thefemoral neckIt can be used with or withoutcement.

Fig. 39.30: Austin-Moore prosthesis

Fig. 39.31: Thompsonprosthesis


Charnley’s total hip prosthesisThis is prosthesis for the replacement of both the acetabulumand the head of the femurThe acetabulum is replaced by a plastic acetabulum cup andthe head by a steel componentBoth the components are fitted totheir respective components byusing bone cementThe size of the head of theprosthesis is 22 mm.

Muller’s total hip prosthesisIt is similar to Charnley’s prosthesis,except for the size of the head ofthis prosthesis which is 32 mmStem is available in differentthickness.

Total knee prosthesisTotal condylar design is the mostpopular one of the differentdesigns availableIn this type, the articular surfacesof the femur (metallic), patella andtibia (plastic) are replacedCommon prosthesis used are Insall-Burstein knee and Freeman-Samuelson knee.

Fig. 39.32: Charnley’s totalhip prosthesis

Fig. 39.33: Total kneeprosthesis

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