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umerous approaches have been used to re-pair fractures and luxations in avian spe-cies. Typically, these techniques have beenadapted from those used for small mam-

mals and humans. Regardless of the specific tech-niques employed in fracture repair, it is important to:

Treat contaminated and infected wounds. Preserve soft tissue structures. Appose, align and control rotation of fractures andreduce luxations. Rigidly immobilize the fracture site.Maintain range of motion in all joints affected bythe fracture or fixation technique. Return the affected limb to “normal function” assoon as possible.

The presence of a fracture certainly suggests majortrauma, and a thorough physical examination shouldbe performed to determine other injuries.

Subcutaneous emphysema may be noted in birdswith ruptured air sacs or with fractures of thehumerus, thoracic girdle or some ribs (the pneumaticbones). The emphysema will generally resolve withina few days. In many cases, birds may require severaldays of stabilization with fluids, steroids, antibioticsor supportive alimentation before anesthesia andsurgery can be safely performed (see Chapter 40).

N C H A P T E R

42ORTHOPEDIC

SURGICAL

TECHNIQUES

Howard MartinBranson W. Ritchie

It is common for subtle injuries to occur that aredifficult to detect by physical examination. Surveyradiographs of affected skeletal areas as well as theabdomen and thorax are needed to assess any bonyor soft tissue changes that may have occurred duringa traumatic episode. Recommendations for otherevaluation procedures are similar to those describedin soft tissue surgery (see Chapter 41).

Fracture stabilization techniques used in free-rang-ing birds must be designed to increase the likelihoodthat a rehabilitated bird can be released. Repair of awing fracture, particularly near a joint, must benearly perfect with no ankylosis and minimal softtissue damage to ensure return to full flight. Forthese avian patients, maintenance and protection ofsoft tissues is the single most important aspect ofsuccessful surgery. The degree and type of soft tissuedamage may be more critical in determining thepotential for postsurgical return to function thanspecific osseous injuries. Native avifauna with inju-ries that will prevent their release must be repairedto a functional level that allows them to adapt to azoo, breeding program or educational facility. Injurednative birds that cannot be repaired to sufficientlyachieve one of these goals may require euthanasia.

Birds that are maintained in aviary situations or inbreeding facilities must have adequate postoperativeuse of a fractured limb to allow them to functioneffectively in their respective environments. Mostcompanion birds can tolerate a substantial loss offunction of the wings and still function normally. Leginjuries that alter weight-bearing in one or both feetcan predispose a bird to bumblefoot or arthritis.Some birds will tolerate postoperative surgical hard-ware while others will not.

Therapeutic Strategies

The fracture should be classified as to anatomy,shape, whether it is open or closed and its chronicity.The type of fracture will frequently dictate the type ofspecific therapy and stabilization procedures that areused. Patient preparation for surgery, preparing thesurgical site and draping are discussed in Chapter 40.

Developing a Surgical Plan

The method of fixation selected should suit the pa-tient’s injury, natural behavior, activity levels andfuture needs (Tables 42.1, 42.2). A thorough under-standing of the location of major nerves, arteries andveins ensures that the surgeon can properly performany necessary stabilization procedure. Bipolar radio-surgery is necessary to control blood loss and allowthorough visualization of a relatively small surgicalfield (see Chapter 40).

Avian bones have a high calcium content, and a thin,brittle nature.31,35 In addition, portions of the medul-lary canal of the humerus in many birds are con-nected to the air sacs (pneumatic), which reduce theweight of the bone and are believed to contribute tothe respiratory cycle during flight (see AnatomyOverlays). It is best to cover the medullary canal ofthe proximal fragment of a humeral fracture beforeirrigating the surgical site. Fluids or necrotic debristhat are flushed into the pneumatic bones may causeasphyxiation, air sacculitis or pneumonia.

The distal legs and wings of birds have relativelylittle soft tissue (ie, tendons, ligaments, skin andmuscles). Bone in these areas are, therefore, particu-larly susceptible to impact-related injuries (see Anat-omy Overlays). Aggressive tissue manipulation cancause increased damage of already compromisedblood supply and soft tissues, which increases thehealing time and likelihood of unsuccessful functionpost-repair.

TABLE 42.1 Types of Fixation

External coaptation - Sling, splint, bandage

Internal fixation - IM pins, cerclage wires, bone plates

External fixation - pins passed through bone from skin surface andconnected to stabilizing bars

TABLE 42.2 Principles of Fracture Stabilization31,30,38,39

Minimal soft tissue damage

Maintenance of length, rotation, angular orientation

Anatomic alignment

Rigid stabilization

Minimal disturbance of callus formation

Neutralization of forces:– Rotation, bending (transverse fractures)– Shear, rotation, bending (oblique or spinal fractures)– Compression, shear, rotation, bending

(comminuted fractures)

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Gentle manipulation and frequent irrigation of softtissues and bones with sterile saline will help main-tain the integrity of vascular and neural structuresand speed return to normal function. If exposure of afracture site requires the transection of a muscle, itis best to do so near the muscle’s origin or insertionin order to minimize trauma and hemorrhage and tofacilitate reattachment. Periosteal stripping anddamage of soft tissue attachments to the bone shouldbe avoided, particularly in the wings, where the pri-mary and secondary feathers are attached to theperiosteum (Figure 42.1).

Open Versus Closed ReductionThin skin, scarce soft tissues and sharp bone frag-ments frequently result in open fractures in birds.Even if bones are not protruding from the skin at thetime of presentation, the presence of any woundassociated with the fracture would indicate previous

violation of the skin barrier. If any skin wound ispresent, the fracture should be considered open.

Closed reduction involves the manipulation of thefracture through application of traction and counter-traction to stretch the soft tissues and appose andalign the bone fragments. It is difficult to achieveadequate alignment and reduction of fractures withclosed reduction techniques without causing signifi-cant soft tissue trauma, except in those fracturesthat are minimally displaced.

The advantages of open reduction include reducedsoft tissue trauma (as traction is applied directly tothe bones), visualization of the fracture site (andtherefore the ability to attain optimal reduction aswell as cleansing of the fracture site) and removalfrom the fracture site of interposed soft tissues, con-taminated or infected debris and necrotic or devital-ized bone.11

PrognosisCompanion and aviary birds rarely require full mo-bility following fracture repair, and the post-fractureprognosis for return to function with these birds isgenerally excellent. By comparison, free-rangingbirds (particularly raptors), which can be viewed asfinely tuned athletes, must have near perfect wingfunction in order to survive in the wild. A slightrotation in the wing (particularly in the distal wing)can alter flight. The ulna and radius normally slideby each other longitudinally. If trauma causes theulna and radius to fuse (preventing this sliding mo-tion), a bird will be unable to properly supinate orpronate the carpus and may not be able to fly.21,41

Fractures near a joint usually result in ankylosis,which prevents normal limb function. Open commi-nuted fractures are more likely to be infected, result-ing in secondary osteomyelitis.21 A 20 to 30% decreasein leg function may be acceptable in birds released tothe wild as long as the dysfunction does not dramati-cally affect the flexion or extension of the foot or theprehension of food.

Postoperative Care Postoperative radiographs should be taken at two- tofour-week intervals to assess bone healing. The ra-diographic changes associated with bone healing canappear similar to those that occur with osteomyelitisincluding periosteal reaction, sclerosis and increasedradiodensities in the medullary canal (Figure 42.2).

To improve vascular supply to damaged tissue and tospeed the bone healing process, active and passive

FIG 42.1 Primary and secondary remiges (arrows) are attached tothe periosteum of the metacarpal bones and ulna, respectively.Periosteal stripping and damage to the primary and secondaryfeather follicles should be avoided during a surgical procedure(courtesy of Laurel Degernes).

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rehabilitative techniques should be instigated assoon as possible after an orthopedic surgery. Thephysical therapy program should be based on thebird’s injury, behavior and required degree of post-surgical function. Initial physical therapy may in-volve only a bird’s daily activities of perching andprehending food. Physical therapy should evolve toinclude a variety of regimented exercises designed tomaintain or increase cardiovascular endurance, tomaintain or increase range of motion of joints and tomaintain or increase muscular flexibility tone andfitness.10 The physical therapy program is dictated bythe exact nature of the injury and species of injuredbird.

Bone Healing

Controlled studies evaluating the healing process ofavian bone are scarce. In general, it is assumed thatthe rate of fracture repair is dependent on the dis-placement of the bone fragments, the amount of dam-age to the blood supply, whether an infectious agentis present and the amount of motion at the fracturesite.14 In mammals, primary bone healing (bonegrowth through the Haversian system with minimalcallus formation) occurs with rigid fixation and doesnot occur if there is a gap or motion at the fracturesite. In these cases, secondary bone healing charac-terized by maximum callus formation occurs (Table42.3). In birds where fractures were repaired withbone plates (maximum stabilization), callus forma-tion was found to be minimal, suggesting that pri-mary bone healing had occurred (Figure 42.3).19

Callus formation appears to be similar in birds andmammals.19 Endosteal callus provides rapid stabili-zation in bones that are properly aligned. Periosteal

FIG 42.2 A minimally displaced mid-diaphyseal tibiotarsal frac-ture in a Green-winged Macaw was stabilized with a cast. Radio-graphs three weeks after the fracture occurred show a loss of detailat the fracture ends and a smooth, well defined periosteal responsecharacteristic of a normal healing process. This lateral radiographindicates slight malalignment and over-riding of the fragments(courtesy of Marjorie McMillan).

FIG 42.3 Radiographic findings suggest that primary bone heal-ing occurs in birds if a fracture is properly aligned and rigidlystabilized. An adult Amazon parrot was presented with a historyof having fractured the right tibiotarsus three months before pres-entation. This fracture was repaired with a Robert Jones bandage.Three weeks before presentation, the bird had fractured the lefttibiotarsus and the limb was cast. The bird had not improved duringthe three-week period, and the case was referred for evaluation.The severely displaced right tibiotarsal fracture was stable and asubstantial periosteal callus was evident radiographically. At pres-entation, the left tibiotarsus was displaced (bone ends were nottouching) and there was excessive soft tissue swelling. The fracturesite was approached medially, and a large amount of fibrous con-nective tissue was removed to allow the bone ends to be reduced.The fracture was stabilized using positive profile threaded pinsconnected with methylmethacrylate. The bird was placed in a lightRobert Jones-type bandage and was using the leg several hoursafter surgery. Radiographs taken four weeks postsurgery indicateda bony union with minimal callus formation.

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callus formation is minimal if the bones are rigidlyfixed. The blood supply to the bones is believed toarise from periosteal (originating from soft tissuesand muscles), medullary (originating from nutrientartery), metaphyseal and epiphyseal vessels.7

Stable, properly aligned fractures appear to healmore rapidly in birds than in mammals.6,7,30,31,45 Ithas been suggested, but not confirmed, that pneu-matic bones heal slower than medullary bones.31

Clinical stability of a fracture (two to three weeks)may precede radiographic evidence that the bone ishealed (three to six weeks).7,31,45 The healing of unsta-bilized humeral fractures in pigeons was charac-terized by increased radiolucency in the medullarycanal and endosteal and periosteal calluses that werepresent histologically by nine weeks. Poorly alignedfractures changed little between four and twelveweeks,31 while properly stabilized bones remodeledrapidly during that time period.

Minor forces that cause undetectable levels of move-ment can damage the growth of small capillary bedsand impede fracture stabilization. Fracture stabiliza-tion is most likely to fail in comminuted fractures thathave the greatest number of forces that must be neu-tralized.30 In these fractures, bone fragments thatmaintain a blood supply should heal as rapidly as theintact distal and proximal fragments. Devitalized, un-infected fragments should be left in place to providestructural support for callus formation (Figure 42.4).33

OsteomyelitisAvian heterophils lack the proteinase necessary toliquify necrotic tissue, and birds tend to form granu-lomas that wall off infectious agents and necroticmaterial. Consequently, osteomyelitis is charac-terized by caseous, dry, non-draining lesions that arefrequently restricted to the site of infection andrarely induce secondary systemic infections.33 Withmild infections, it is common for the host defensemechanism to wall off the necrotic debris and formcallus around the infected tissue. However, thesegranulomatous osteomyelitis lesions can serve as anidus for infection that can cause a fatal septicemiaif a bird becomes immunosuppressed.

Large quantities of necrotic debris may prevent bonehealing and should be surgically removed if success-ful fracture stabilization is expected to occur.33,46 De-bridement and flushing should be used to removenecrotic tissue and debris from all open fractures toreduce the chances of postoperative osteomyelitis.Samples for culture and sensitivity should be col-lected from the fracture site at the time of surgery.The use of intraoperative, broad-spectrum antibiot-ics with good tissue penetration (trimethoprim-sulfa,cephalosporins, chloramphenicol, tetracyclines)should be considered in these cases.

Placement of stabilizing hardware at or near an openfracture site should be avoided to decrease the likeli-hood of osteomyelitis and improve the speed of bonehealing. External fixators are recommended in thesecases. It has been suggested that fractures in pneu-matic bones would be predisposed to osteomyelitisfrom contaminated air entering the fracture site.There is no evidence to support this theory.7,31

MalunionsViable and nonviable malunions can occur in birds(Table 42.4). Malunions occur when the ends of frac-tured bones heal but not to each other. Stabilization

FIG 42.4 In comminuted fractures, bone fragments that maintaina blood supply heal rapidly. Devitalized, uninfected fragmentsshould be left at the fracture site to provide additional support forcallus formation (courtesy of Laurel Degernes).

TABLE 42.3 Secondary Bone Healing

Induction and InflammationFibroblasts proliferateOsteogenic cells migrate from periosteum and endosteum andproliferate at fracture site

Callus FormationCollagen and mucopolysaccharide producedCalcium deposited in callusSoft callus becomes bone (endochondral ossification)

RemodelingAccelerated deposition and resorption of boneChange in shape of boneFunction and strength restored


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requires removing necrotic debris,freshening the bone ends and com-pressing and rigidly stabilizing thefracture site.41 Electrical currentstimulation was used to repair a non-union fracture (six months’ duration)in the radius and ulna of a Rough-legged Hawk. A direct-current stimu-latora was implanted and delivered0.83 volts at 20 uA to the fracturesite. Callus formation was evidentradiographically at 21 days post-im-plantation and the fracture washealed by 80 days post-implanta-tion.27

Ossification13

The maturation process of the longbones of birds is different from thatof mammals. In the majority of rap-tors, ossification of the limb bonesoccurs within 60 days of hatchingand bones appear to mature thereaf-ter. The diaphysis, or shaft, is thatportion of a long bone between the ends (Figure 42.5).The metaphysis is the wider part of the extremitiesof the shaft, adjacent to the epiphyseal disc (physis).The epiphysis is the end of a long bone and is formedfrom a secondary center of ossification. The physis, orgrowth plate, is that segment of tubular bone con-cerned with growth. It is divided into four distinctzones:11

Zone of resting cartilage: Small chondrocytesare dispersed in an irregular pattern.Zone of cell proliferation: Chondrocytes aresomewhat larger and tend to form columns; this isthe area of chondrocyte proliferation and mitoticfigures are usually present.Zone of cell maturation: Cells are larger stilland arranged in columns. As the cells enlarge andmature, they accumulate glycogen and begin pro-ducing phosphatase, which initiates calcification.Zone of calcification and ossification: Withmaturity, the columns of chondrocytes die anddisintegrate, leaving spaces between partitionswithin the cartilage. Capillaries invade the spacesand osteoblastic activity takes place on the surfaceof the partitions. Longitudinally oriented bonytrabeculae develop, which give a jagged appear-ance to this zone on histologic and radiographicpreparations.

In mammals, most long bones have one or moreepiphyseal or secondary centers of ossification. Theirformation is similar to endochondral ossificationwith proliferation occurring in all directions until apredetermined size is reached. The epiphyseal centeris covered distally by hyaline articular cartilage andproximally by an epiphyseal plate or physis until theanimal reaches maturity.

The tibiotarsus of birds appears to follow a classicmammalian ossification pattern. The ends of thebones grow rapidly and establish secondary centersof ossification (epiphyses). The growth in lengthtakes place at the epiphyseal layer, and when growthceases, the layer of cartilage ossifies. The avian hu-

TABLE 42.4 Types of Malunions3

Viable – Sufficient blood supplyHypertrophic

Abundant callus and blood vesselsFractures filled with fibrocartilageCaused by inadequate fixation or premature loading

OligotrophicNo evidence of callusBiologically, fracture can healHypervascularized fragmentsRounded, decalcified fragment ends

Nonviable – Insufficient blood supply

FIG 42.5 a) Mammalian long bone ossification during early development and b) after theepiphysis has reached maximum size. 1) articular cartilage 2) secondary center of ossifi-cation 3) zone of resting cartilage 4) zone of cell proliferation 5) zone of maturation 6) zoneof calcification and ossification 7) physis 8) metaphysis and 9) diaphysis (modified withpermission from Fowler13).

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merus, radius, ulna and femur ap-pear to have different patterns of os-sification.

The basic progression of ossificationin long bones has been described inchickens (Figure 42.6). In the femurof a 9-day-old embryo, a sheath ofbone has begun to form beneath theperichondrium of the original hya-line cartilage. At 13 days, the centraldiaphyseal cartilage has been re-placed by bone, and the marrow cav-ity has formed. Endochondral ossifi-cation progresses toward bothextremities.

In the day-old chick, the diaphysishas elongated by replacement of thecartilage model at the metaphysis.There is also a cartilage model analo-gous for the mammalian epiphysealcenter of ossification (Figure 42.7),but the epiphyseal cartilage does notundergo endochondral ossification inthe femur of chickens as it does inmammals. Instead, it persists as awide basophilic hyaline zone coveredby a narrow strip of eosinophilic ar-ticular cartilage. Elongation of thecartilage model is accomplished byinterstitial growth of chondrocytes.11

At a predetermined time (may becontrolled by age, species, nutrition),the growth cartilage becomes ex-hausted. The invading marrow tis-sue then enters the epiphyseal carti-lage (Figure 42.8). Individualchondrocytes undergo hypertrophyallowing final endochondral ossifica-tion of the epiphyseal cartilage. By190 days, ossification is essentiallycomplete. At each end of the bone, adense terminal bone plate is coveredby an articular hyaline cartilage. Itis possible for slight elongation of along bone to take place by cartilageproliferation and ossification at thejunction of the bone and articularcartilage. This is typical of the longbones of the humerus, radius, ulnaand femur.

FIG 42.6 Ossification of avian long bones from day 9 to day 13. 1) nutrient artery 2)periosteum and initial bone plate 3) zone of proliferation 4) zone of maturation 5) marrowcavity 6) cortex and 7) physis (modified with permission from Fowler13).

FIG 42.7 a) In contrast to mammals, the epiphyseal center of the avian long bone remainscartilaginous (day-old chick). b) After the maximum bone size is reached (in this case a155-day-old chick), the epiphyseal cartilage undergoes endochondral ossification. 1) ar-ticular cartilage 2) epiphyseal cartilage 3) zone of resting cartilage 4) zone of proliferation5) zone of maturation and 6) zone of calcification and ossification (modified with permis-sion from Fowler13).


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The ossification of the tibiotarsal and tarsometatar-sal bones is different. The epiphyseal center of ossifi-cation of the proximal end of the tibiotarsus becomesvisible radiographically at 35 days in the chicken.The fibular and tibial tarsal bones, which make upthe hock of mature mammals, fuse in avian embryosto the tibial cartilaginous model and appear as twoepiphyseal centers in the seven-day-old chick. Like-wise, the epiphyseal center at the proximal end of thetarsometatarsus corresponds to the distal row of tar-sal bones in mammals. The carpals, metacarpals andphalanges of the wing ossify from a diaphyseal centerin the same manner as long bones of the wing.

Metabolic Bone DiseaseMetabolic bone disease in the tibiotarsus and tar-sometatarsus (bones with epiphyseal centers of ossi-fication) appears similar to that described in mam-mals. If growth of the long bone continues byinterstitial cartilaginous growth in the zone of prolif-eration without a sufficient supply of calcium andphosphorus, calcification of the intracellular sub-stance between the mature cells ceases. Without cal-cification, the chondrocytes continue to live, causingthickening of the whole growth zone (Figure 42.9).Osteoblastic activity continues with the production ofunmineralized osteoid tissue in the metaphysis. Thestimulus for osteoid production is intensified because

of the relative structural weakness of the unmineral-ized growth zone. This excessive osteoid productionoccurs subperiosteally, resulting in knobby growthcenters. The radiographic changes are characterizedby rickets, increased width of the physis, increasedtrabeculation in the metaphysis, lipping of the meta-physis and swollen distal extremities.40

The femur and wing bones lack epiphyseal centers ofossification. However, histologically, the same pat-tern of abnormal development takes place in thegrowth zone of a femur or wing bone in a bird withmetabolic bone disease. The epiphyseal cartilage inbirds corresponds to the epiphyseal ossification cen-ter in mammals.13

Bone GraftsBone grafts promote fracture healing through osteo-genesis (production of new bone), osteoinduction (re-cruitment of mesenchymal cells that differentiateinto chondroblasts and osteoblasts) and osteoconduc-tion (osteoblast ingrowth from the host into the graftproviding structural and mechanical support). Ingeneral, cancellous bone is better than cortical bone

FIG 42.8 Progression toward mature bone in a 190-day-old chick.1) articular cartilage 2) epiphyseal cartilage 3) dense layer of bonebeneath articular cartilage 4) physis 5) bone trabecula and 6)cortex (modified with permission from Fowler13).

FIG 42.9 Comparison of normal avian ossification and ossificationin a bone affected with metabolic bone disease. 1) articular carti-lage 2) epiphyseal cartilage 3) physis 4) bone spicules 5) osteoidspicules 6) cortex, and folding fracture (modified with permissionfrom Fowler13)

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for grafting because the former has a larger surfacearea and a large number of viable cells for stimulat-ing new bone production.

Autogenous medullary bone (collected from the tibio-tarsus), corticocancellous bone (collected from thesternum or ribs) and cortical bone (devitalized frag-ments from the fracture site) have been shown toaugment bone healing in birds.33,35,41 Cortical allo-grafts (same species, different individual) andxenografts (different species) were not found tostimulate nor inhibit bone healing when applied inan overlay fashion to humeral fractures in pigeons.There was less callus formation in the fractures sup-ported by a graft but these birds also had a signifi-cantly higher occurrence of dehiscence, sequestra-tion and foreign body reactions than birds with nografts.28 These findings suggest that the positive ef-fects of cortical bone grafts in birds are limited toadded fracture stabilization.

Fracture Repair Techniques

It is best to have a command of a variety of fracturefixation techniques and to be ready with alternativeplans at the time of surgery (see Table 42.1). Reas-sessment of the injury intraoperatively may necessi-tate a change in the surgical procedure. Each avianfracture is unique and may require a variety of ma-neuvers, techniques and instruments to achieve op-timal reduction and immobilization.

Many closed fractures may heal without any type ofcoaptation or fixation. However, with unsupportedlong bone fractures, excessive callus formation,malalignment of the bone ends and shortening of thelimb (overridden fractures) will dramatically reducenormal function. Non-displaced fractures of the pel-vic girdle, coracoid, clavicle and scapula will gener-ally heal with minimal support.21,39,46 Displaced frac-tures of the coracoid must be surgically repaired orthe fracture will usually result in an inability to fly.46

Fractures of the radius or ulna, in which the otherbone is intact, can generally be repaired with exter-nal coaptation and forced rest (Figure 42.10).38

External Coaptation: Bandages and Splints

External coaptation is an inexpensive and rapidmethod of providing increased comfort to a patient(decreased movement of bone ends) and minimalstabilization of a fracture. Bandages and splintsshould be made of the lightest weight materials withthe minimal amount of padding needed to compen-sate for swelling of damaged soft tissue. Externalcoaptation is acceptable as a primary stabilizationtechnique only when a limited post-fracture range ofmotion is satisfactory, a patient is too small to facili-tate surgical repair, a fracture is minimally displacedor anesthesia and surgery would jeopardize the pa-tient’s life (eg, liver failure, kidney failure, heartdisease, head trauma).

Fracture disease (malalignment of bone ends, muscleatrophy, joint ankylosis, shortened bone length andtendon contraction) is common in fractures repairedby external coaptation (Figure 42.11). In general,external coaptation should be considered an emer-gency method of stabilizing fractures until surgerycan be performed or for providing additional supportfor fractures repaired by other methods.

Some companion birds may not require full return toflight; in these patients, some wing fractures can beeffectively managed with external coaptation. Ban-dages or splints can be used to repair fractures of thedistal legs and feet if the fracture can be properly

FIG 42.10 Minimally displaced fractures of the radius or ulna inwhich the other bone is intact can generally be repaired with afigure-of-eight wing-body wrap and forced rest; a) before and b)after coaptation (courtesy of Laurel Degernes).


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aligned and if any decrease in bone length does notalter the weight-bearing capacity of either limb andpredispose the patient to arthritis or pododermatitis(see Chapter 16). Additionally, if leg function is al-tered, the companion bird may not be able to ambu-late or adequately prehend food.

External Fixators

Bony injuries in the avian patient tend to heal in areasonable manner and are amenable to a variety offixation methods. In contrast, maintenance of softtissues and joint mobility, the most vital componentsof return of full function for birds, may be hinderedby many of the techniques used for immobilization offractures and luxations. External fixators are gener-ally considered the best stabilization technique forimmobilizing fractures in birds that require a fullreturn to function.

Numerous types of external fixation devices havebeen described for use in birds (Table 42.5). A varietyof Kirschner wires and Steinman pins may be passedinto the bones, and a variety of connecting bars andacrylic cements can be used for stabilizing thepins.6,16,25,26,37,45 These devices are inexpensive, light-weight, easy to remove and are well tolerated bymany avian species. An external fixator can be easilyremoved from a calm patient without anesthesia.When properly used, external fixators provide rigidstabilization and preserve joint and periarticularstructure, while neutralizing rotational, bending andshear forces.14,21,24,25,26,35,46 The approach to the surgi-cal site can be minimal and, therefore, decreases softtissue damage and reduces post-fixation dysfunctionof the limb.16,18,19 In many cases, external fixators

allow a bird to use a repaired limb within severaldays of surgery (Figure 42.12).

External fixators can be applied in conjunction withIM pins to further neutralize rotation and increasestability.43

Type II (through-and-through) fixators are more sta-ble and stronger than Type I fixators, which tend toloosen rapidly (Table 42.5).6 The use of positive-pro-file threaded pins in a Type I fixator configuration is

FIG 42.11 VD radiograph of a falcon with post-traumatic degen-erative joint disease of the elbow. Improper fracture repair tech-niques are frequent causes of fracture disease in birds.

FIG 42.12 An external fixator is an ideal way to repair manyfractures in birds. Either KE connectors, various cements or cast-ing materials can be used to connect the stabilizing pins. In thiscase, a valgus deformity of the tibiotarsus was corrected with adome osteotomy and stabilized with a Type II external fixator. Theconnecting bars should be as close to the skin edge as possible.

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particularly useful in repairing fractures of the proxi-mal humerus and femur, where interference with thebody wall makes it difficult or impossible to place aType II fixator (Figure 42.13).

External fixators are ideal for corrective osteotomiesand open, comminuted fractures. In the latter situ-ation, the fixator can be placed so that an infectedwound can remain open for several days for flushingand evaluation.

Application of an External FixatorExternal fixator pins should be placed by making asmall incision in the skin, and should not be placedthrough a primary incision site or open wound. Thisplacement technique will decrease the likelihoodthat the pins will promote an infection at the surgicalsite. Pins should be inserted so that they avoid largemuscle masses (minimizes loosening) and should bepassed through pre-drilled holes to decrease wobble(improperly increases the size of the hole) and in-crease pin purchase on the cortices. It is best to placefrom three to four pins on each side of a fracture todecrease the stresses on any one pin. A minimum oftwo pins must be placed in each bone segment toensure that the fixator will provide adequate fixationwithout rotation.

Positive-profile threaded pins inserted through pre-drilled holes have been found to maintain solid bone-to-pin interfaces for prolonged periods (up to threemonths) in some birds (Aron DN, unpublished). Bycomparison, other types of threaded or unthreadedpins are frequently loose in the cortex within three tosix weeks of insertion. The diameter of positive-pro-file threaded pins is not reduced by the threadingprocess and these pins are less likely to fail from thestress-riser effect than other types of threadedpins.2 Placing unthreaded pins at an angle (35 to55°) perpendicular to the bone will decrease thechance that the fixator will slip from side to side, but

TABLE 42.5 Fixator Types Listed in Increasing Strength

Type I Half-pin splint - Pins penetrate one skin surface andboth cortices. Connecting bars only on one side of thelimb.

Type II Full pin splint - Pins pass through both skin surfacesand both cortices. Connecting bars on both side of thelimb in one plane.

Type III Type I and Type II splints placed at a 90° angle toeach other. Fixators are connected to each other.Creates a three-dimensional frame.

FIG 42.13 Type III fixators provide maximal stability by correct-ing fracture motion in two planes. Biplanar fixators are particu-larly useful for repairing femoral fractures where a connecting barcannot be placed on the medial side of the bone because of inter-ference with the body wall. In this drawing, the connecting barshave been moved away from the skin for clarity purposes. 1) femur2) connecting bars 3) stabilizing bars and 4) cross bar.


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would not be expected to be as effective as positive-profile threaded pins.

The connecting bar for the fixator pins should beplaced as close as possible to the skin (taking intoaccount anticipated swelling) to increase thestrength of the apparatus. Standard Kirschner-Eh-mer (KE) fixator hardware can be used to stabilizefractures in medium- or large-bodied birds. Theirprimary limitations are their size and weight.

It is extremely difficult to properly align a group ofstabilizing pins that are passed free-hand. If they arenot properly aligned, the pins cannot be attached tothe connecting bars by KE fixator hardware. Theeasiest way to apply a KE fixator is to place the mostproximal and distal stabilizing pins through thebone. The connecting bar is equipped with the de-sired number of clamps (minimum of four), and thefirst and last clamps are connected to the alreadyinserted proximal and distal pins. The interiorclamps are then used as a drill guide for placementof the remaining stabilizing pins.

In addition to KE clamps, stabilization pins can beconnected with polymethylmethacrylate,b cast mate-rialc and dental acrylic.26,29,36,38,45 In comparison to KEclamps, these materials are inexpensive, lightweightand are malleable so that pins that are not in perfectalignment can be easily connected. The tips of thestabilizing pins can be carefully bent parallel to thelong axis of the bone to increase their holdingstrength in the connecting material. During thebending process, the pin should be stabilized to en-sure that no forces are applied to the fracture site,the bone pin interface or associated joints.

Polymethylmethacrylate (PMM) can be attached tothe stabilizing pins by mixing the material until it isthe consistency of dough and then molding it aroundthe stabilizing pins. The material can also be used bypassing the stabilizing pins through a hole in a clearplastic tube (eg, clear straw). The plastic tubes usedfor a mold should be thin-walled to ensure that themethylmethacrylate column is of adequate diameter(approximately equal to that of the bone). When thepins are properly positioned (fracture site reducedand in proper alignment), the PMM is placed in asyringe and injected into the straw while it is stillliquid. The fracture is held in place until the PMMhardens (generally ten minutes).

A soft metal connecting bar with numerous holes hasrecently become available.d The stabilizing pins arepassed through the holes in the connecting bar, which

is then crimped to firmly secure the pins. Theseconnecting bars are light-weight and inexpensive.16

In birds that weigh less than 200 g, hypodermicneedles can be used as stabilizing pins and these canbe attached with cyanoacrylate glue (SuperGlue) toother needles or tooth picks that function as tempo-rary connecting rods. An index card can be fashionedinto a V-shaped trough and placed over the pins.Five-minute epoxy cement is then poured into thetrough to firmly bind the stabilization pins and con-necting bars.

Intramedullary Fixation

Intramedullary PinsGenerally, intramedullary pins neutralize bendingforces and provide adequate fracture alignment, butthey do not protect the fracture from rotational orshear forces.6,21,33,46 Minimal rotational deformities inthe wing bones can inhibit flight by altering thedynamics of the wing aerofoil.9,19,46 Techniques thatuse IM pins in combination with external coaptationhave been frequently discussed in the literature;however, the combination of these two fixation tech-niques should be avoided to prevent ankylosis of theassociated joints.6,8,14,16,19 Because of the relativelythin cortices of birds, the use of threaded IM pins hasbeen suggested to provide better bone purchase thannon-threaded pins.36,37,42 However, IM pins are pri-marily used to counter bending force which would notbe influenced by the degree of purchase in the cortex.21

Editors’ note: Intramedullary pins have several dis-advantages when compared to external fixators. Theyhave the inherent potential to cause articular andperiarticular damage resulting in ankylosis of thejoints. Even properly placed pins that exit near a jointcan cause sufficient tendon or ligament damage, re-sulting in a partially dysfunctional limb. Unless anIM pin can be placed so that it does not exit throughor near a joint, it is best not to use this method ofinternal fixation in birds that require full post-fixa-tion use of a limb. Even pins that do not exit near ajoint can still injure the vasculature and significantlyalter the growth pattern of the bone.13

Retrograde placement of pins through the distalhumerus, normograde placement from the lateral ormedial epicondyle of the humerus, placement throughthe distal ulna or retrograde placement from the el-bow can cause severe periarticular fibrosis and wingdysfunction.17,46

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The use of IM pins, with or without interfragmentarywires, is effective for stabilizing some fractures incompanion birds when clients are not concerned withpostsurgical return of flight. When IM pins are used,they should be of sufficient size to fill about one-halfto two-thirds of the medullary canal.12,36-38 In mam-mals, current theories suggest that the pin shouldoccupy approximately 60% of the medullary canal;however, in birds, excessively large pins can interferewith endosteal blood supply, which may cause avas-cular necrosis or iatrogenic fractures.6,8,14 In order tocompensate for these problems, stack-pinning, cross-pinning or Rush-type pinning with multiple, small-diameter pins has been recommended for use inbirds. However, placement of the pins with any ofthese techniques induces excess cortical damage.

Cerclage, hemicerclage and interfragmentary wirescan be used as an adjunct to internal or externalcoaptation to neutralize rotational and shear forces.They are most useful for adding stability to longoblique and spiral fractures and for holding frag-ments of bone in apposition during the application ofother fixation devices.41

Long bone fractures fixed with intramedullary pinsalone are often immobilized with bandages or splintsfor 10 to 21 days. A significant loss in post-surgicalrange of motion should be expected when bandagesare used in combination with intramedullary pinning.3

Intramedullary Polymer PinsSeveral techniques have been described for the inser-tion of high-density polymer rods, polypropylenewelding rods or polymethylmethacrylate into themedullary canal.17,24-26 Plastic and acrylic rods havebeen successfully used in combination with externalfixators for additional stability. The polymer rods arelighter than IM pins, inexpensive, biologically inert,provide for stable fracture repair and do not requireremoval when the fracture is healed.4,21,24

In one study, fractures of the wing repaired with IMpolymer rods allowed rapid post-fixation exercise(seven to ten days) and most birds were able to fly 14to 21 days postsurgery. 24 However, because the rodsmust be inserted using a shuttle technique (techni-cally difficult), the length of the pin is limited to thelongest fracture segment and the pin may not bepassed into the shorter fragment segment to a suffi-cient depth to provide adequate stability.24-26 Addi-tionally, these techniques dictate that a foreign ma-terial remain in the medullary canal, which is likely

to alter the biomechanical response of a portion of thewing to stresses induced by flight.24

Intramedullary PMMPolymethylmethacrylate has been used in the intra-medullary canal of birds to aid in fracture stabiliza-tion. This material comes as a liquid monomer and apowdered polymer that, when mixed together, under-goes polymerization that is exothermic (100°C).16,19

The high temperatures associated with polymeriza-tion do cause bone necrosis, and application of coolwater has been suggested as a method of dissipatingheat.18,35 The material generally hardens in ten min-utes. This method of fracture fixation does have theadvantage of being fast and inexpensive, providingrapid stability and allowing almost immediate re-turn to function without joint insult.

The inhibition of endosteal callus formation, en-dosteal blood supply (that is theorized to occur) andthe intramedullary bone necrosis (that is known tooccur) have not been shown to interfere with theclinical outcome of fracture healing.18,19,21,35 The mostsignificant interference with healing occurred whenpolymethylmethacrylate was allowed to pass be-tween the bone ends and inhibit callus formation. Ifthe humerus or femur are overfilled with PMM, thematerial may enter the connecting air sacs.

Methylmethacrylate should not be used in openwounds where infectious agents are likely. If themethylmethacrylate is contaminated with bacteria,the material can serve as a chronic source of infec-tion.18,19 The necrosis that occurs during the polym-erization process and the damage to the endostealblood supply would theoretically predispose an af-fected limb to osteomyelitis.35 In humans, heat-stableantibiotics (cephalothin, potassium penicillin) havebeen added to the polymer to provide up to five yearsof bacteriostatic activity.35,44 The effects of long-termexposure of birds to these antibiotics have not beeninvestigated.

Given the uncertainties about the long-term effectsof IM PMM (particularly in the wing bones of free-flighted birds), this technique should be used withcaution. Techniques have also been reported usingpolymer rods in conjunction with IM PMM.10,22,23 Theadvantages and disadvantages of these techniquesare similar to those described with either techniquealone.


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Bone Plates

Bone plates have been infrequently discussed for usein birds because of their thin cortices (undeterminedwhether a real or perceived concern) and their rela-tive lack of soft tissue.6,14,24,41,46 In addition, tradi-tional bone plating equipment is expensive and thetechnique requires specialized training and pro-longed anesthesia times.

The availability of small, lightweight bone plates hasmade these devices more worthy of consideration forrepairing some avian fractures. Small finger platesdesigned for humans, cuttable metal platese andacrylic plates are available in sizes useful for frac-tures of long bones in birds of 350 g or more. 5,15,19

Bone plates have been successfully used to achievewhat clinically and radiographically appear as pri-mary bone healing in larger birds (ratites).20,41 Whenthey are used, bone plates have the advantage overother fixation techniques of providing rigid fixationwith minimum callus formation and joint involve-ment.18,19,33,35 Another advantage of plates is that theyare completely internal and therefore are well toler-ated by birds.

The stress junction at the end of the plate is suscep-tible to fracture. In raptors, plates used for the repairof closed fractures resulted in long healing times andrehabilitation periods, but produced excellent reduc-tion and alignment of the fractures and a high levelof return to full function.9

Some avian fractures are not conducive to being re-paired with bone plates. Plates can serve as a nidus forinfection and are not recommended for use in openfractures. Plates usually require a relatively long heal-ing and rehabilitation time because of the “shieldingeffects” the plate induces with respect to underlyingbone. After a plate is removed, the underlying bone mayfracture (usually through the screw holes) if normal useis resumed immediately. Therefore, gradual physicaltherapy programs should be instituted. Movementshould be limited for the first seven to ten days follow-ing removal of the plate, and then the bird should beallowed to gradually return to normal function. Plates

can conduct cold and lead to deep bone pain as wellas frostbite of surrounding tissues and should gener-ally be removed in birds that will be released to thewild. Plates can remain in place if the bird is notexposed to freezing temperatures or the plate doesnot cause any specific problems.

Doyle Technique

A fracture fixation method has been developed (DoyleJE, unpublished) that combines intramedullary pin-ning concepts with those of external fixation (Figure42.14). In both the distal and proximal fracture seg-ments, a pin is placed through one cortex and angledto bounce off the opposite cortex and remain in themedullary canal (Figure 42.15). Hooks are fashionedon the external end of each pin, and the fracture siteis then compressed and stabilized by stretching adental impact type rubber bandf over the hooks ofeach pin. The technique requires that the smallestfracture segment be of sufficient size for the safeplacement of a stabilizing pin. Kirschner wires(0.028, 0.035, 0.045 or 0.062 cm) are adequate formost avian fractures. In small birds, various-sizedcatheter needles or hypodermic needles can be usedin place of the K wires.

This technique compensates for several problemsthat typically occur with intramedullary pinningtechniques:

The pins placed in the medullary canal do notdamage periarticular tissue.Smaller pins can be used in order to prevent tra-becular damage and excessive fixator weight.Maximum compression of the fracture site isachieved.

CLINICAL APPL ICAT IONThe long-term effect of infusing polymethylmethacrylate intothe medullary canal of birds has not been determined. Thepresence of any foreign material in the medullary canal of abone would be expected to change its response to appliedforces (particularly those involved with flight).

FIG 42.14 Use of the Doyle technique to repair a diaphyseal tar-sometatarsal fracture in a cockatoo.

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The joint is not involved in the repair process.The bird will have less of a problem with fixation-induced fracture disease.

As with any pin that is placed through the cortex, thestabilizing pins used in this technique should beinserted through pre-drilled, appropriately sizedholes (smaller than the pin size). The pin is insertedas far away from the fracture as possible withoutcompromising the periarticular tissues. Once the pinhas entered the cortex, the angle is changed so thatthe pin bounces off the opposite cortex and can bethreaded into the medullary canal, past the fracturesite and as deep as possible into the smaller fracturesegment (the long pin should not penetrate throughthe cortex in the smaller segment) (Figure 42.15).

The exterior portion of the pin is bent in two placesusing locking pliers. A right angle bend is placed in thepin as it exits the skin so that the pin is relativelyperpendicular to the bone. A semicircle (hook) is fash-ioned in the end of the pin about 1 cm from the skin. A

second pin is placed in the smaller fracture segment.This pin is inserted at a 45° angle to the long axis ofthe bone and parallel to the initial pin. This pinshould penetrate but not exit the opposite cortex. Arubber band is placed around the hooks to compressthe fracture. Postoperatively, several opened gauzepads are placed between the skin and the rubberband to prevent irritation. The affected appendage isplaced in an appropriate bandage (leg: Robert Jones;wing: figure-of-eight body wrap). The rubber bandscan generally be removed within 10 to 21 days, andthe pins between 21 and 40 days after surgery.

Fractures that are minimally displaced and haverecently occurred can be repaired in a closed fashion.Fractures that are several days old or that are dis-placed must be repaired in an open fashion, and anytissue debris or fibrous connective tissue should beremoved from the bone ends. Either cerclage wires orfracture transversing staples can be used to mini-mize over-riding or rotation in oblique and commi-nuted fractures (Figure 42.16). Transverse fractures

FIG 42.15 a) Doyle technique to repair long bone fractures. This technique allows for the use of intramedullary pins while reducing thedegree of perivascular and trabecular damage and providing the maximum compression of the fracture site. Note that the longest pin doesnot penetrate the cortex of the bone, and that the shortest pin is placed into the cortex. b,c) A battery- or air-driven drill is used to placethe pins. A dental rubber band attaches the cupped ends of the pins. d) In small birds, side cutters are used to notch the hubs of hypodermicneedles, which are used in place of intramedullary pins.14a


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FIG 42.16 Doyle staple technique: a) To prevent frac-ture rotation, the bone ends are notched, and a sectionof IM pin wire is bent and placed into pre-drilled holes.b) The wire is passed around the bone using a slottedperiosteal elevator and c) is tied over both sides of thestaple.

FIG 42.17 Doyle technique for slotting the endof fractures to reduce rotation. The bone endsare most easily notched using a sagittal saw.For additional stability, a section of the boneend can be removed (arrow) and placed in a slotcreated in the end of both fracture segments.

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are most likely to rotate. This rotation can be reducedby notching the ends of the bone fragments with asagittal saw and then applying a Doyle compressionapparatus (Figure 42.17).

The Doyle technique can be used in combination withcleaning, calcium hydroxide and acrylics to repair thebeak and fractures of the mandible. Pins are placed intothe fracture segments and connected with rubberbands. The fracture site and beak defect are coveredwith calcium hydroxide paste to prevent dental acrylicfrom entering the defect and causing a malunion. Thefracture is then covered with dental acrylic or a hy-droactive dressing. The defect and fracture will gener-ally require six weeks to heal (Figure 42.18).

Surgical Approaches

During a surgical procedure, every attempt should bemade to identify and follow the natural separationsbetween muscles and along fascial planes. In mostinstances, surgical approaches can be planned toavoid muscles completely, which will reduce the de-gree of surgically induced soft tissue damage. Inci-

sion or bruising of the propatagium should always beavoided.

The Wing

The CarpometacarpusFigure 42.19 illustrates the anatomy of the wing.Repair of metacarpal fractures is meticulous. If thesingle artery and vein located between the third andfourth metacarpal bones are damaged, avascular ne-crosis to the distal portion of the wing can occur.41 Themost direct approach to fractures of the carpometa-carpus is the dorsal approach. The bone can be visu-alized immediately beneath a dorsal skin incision. Aventral approach requires that soft tissues, tendonsand blood vessels be separated in order to approachthe main, or primary, metacarpal bone. Minimallydisplaced closed fractures of the carpometacarpusmay be repaired with a figure-of-eight bandage (seeChapter 16). The clinical drawback to bandages isthe loss in range of motion of the carpal joint whilethe fracture is healing.

Fractures of the carpometacarpus are ideally suitedfor small, lightweight external fixators that allowfreedom of movement in the carpal joint. These areusually applied using small K wires or hypodermicneedles and then attached by a connecting bar com-posed of plastic tubing filled with methylmethacry-

FIG 42.18 a) A bite wound to the mandible in a conure resulted in rhamphothecal damage. A Doyle apparatus was applied to stabilize thefracture. The defect in the beak was covered with calcium hydroxide and a hydroactive dressing before being sealed with cyanoacrylate. b)The pins and cyanoacrylate were removed in four weeks and the mandible and beak were healed.


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FIG 42.19 Overview of surgically important anatomic features of the left wing. Dotted lines represent surgical approaches to the humerus.a) Ventrodorsal view and b) Dorsoventral view.

1) M. tensor propatagialis 2) M. rhomboideus superficialis 3) M. latissimus dorsi cranialis 4) M. scapulohumeralis caudalis 5) M. latissimus dorsi caudalis 6) M. pectoralis 7) M. deltoideus major 8) M. triceps brachii 9) radial nerve10) radial artery11) M. biceps brachii12) humerus13) M. supinator14) M. ectepicondylo-ulnaris15) M. extensor metacarpi ulnaris16) M. extensor digitorum communis17) radius18) M. extensor longus digiti majori19) M. extensor longus alulae20) M. ulnometacarpalis dorsalis21) M. flexor digiti minoris

22) M. interosseus dorsalis23) ulna24) area of M. extensor digitorum communis25) M. pectoralis propatagialis26) keel27) brachial vein28) ulnar artery29) ulnar nerve30) M. pronator superficialis31) M. pronator profundus32) M. flexor digitorum superficialis33) M. flexor digitorum profundus34) M. extensor carpi radialis35) M. ulnometacarpalis ventralis36) M. interosseus ventralis37) area of artificial muscle separation38) M. brachialis39) M. flexor carpi ulnaris

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late cement. IM pins may be added to help withalignment; these are usually placed through the frac-ture site and normograded distally and then retro-graded back to the proximal fragment. Passing IMpins normograde from the carpus reduces the dam-age to the carpal joint.41

In larger birds, small plates may also be used; how-ever, wound closure may be difficult due to the lackof subcutaneous tissues.

The Radius and UlnaOccasionally, birds are presented with fractures ofthe radius alone. Given the larger size of the ulna,radial fractures are often anatomically stabilized andsplinted by the larger ulna. Bandages or simple en-closure rest may result in adequate fixation of mini-mally displaced radial fractures. If displaced, IMpins introduced through the fracture site and normo-graded out toward the carpus (avoiding the joint) andthen retrograded back through the proximal frag-ment may be useful in reducing the fracture. Exter-nal fixators may be used alone or in combination withIM pins. External fixators are easily applied to ulnarfractures.

Traumatic injuries frequently cause fracture of boththe ulna and radius. For minimally displaced mid-shaft fractures, bandaging or external coaptation

(figure-of-eight to immobilize the elbow and carpus)may be adequate. However, given the resulting de-crease in range of motion of the elbow and carpaljoints, it is preferable to repair these fractures withexternal fixators. Concomitant use of intramedullaryor shuttle pins to provide alignment and increasedstability is helpful. Plates may also be used on frac-tures that are closed.

The dorsal approach to the radius and ulna is pre-ferred. An incision is made on the dorsocranial aspectof the ulna just cranial to the insertion point of thesecondary feathers (Figure 42.20). In some cases inwhich both bones are broken, repair of the ulna aloneis sufficient. However, with severely displaced frac-tures, the surgeon may need to stabilize the radius toallow proper healing. The same incision may be use-ful for stabilizing both bones depending on the loca-tion of the radial fracture. The intraosseous spacebetween the radius and ulna houses the radial nerveand the radial artery, both of which should beavoided. The ulna can be easily identified and exteri-orized for debridement and repair through the dorsalincision. If intramedullary pins are used, they areintroduced through the fracture site and retrogradedout the olecranon (avoiding the elbow) and then nor-mograded into the distal fragment.

FIG 42.20 Dorsal approach to the radius and ulna. a) An incision (dotted line) is made in the dorsocranial aspect of the ulna just cranialto the insertion point of the secondary feathers. b) A type II fixator is preferable for stabilization of the ulna. The ventral connecting barshould be padded to reduce damage to the body wall. The dorsal connecting bar has been elevated away from the skin margin for claritypurposes. 1) radius and 2) ulna.


1155

To approach the radius separately, an incision ismade over the dorsal aspect of the radius betweenthe extensor metacarpi radialis muscle anteriorlyand the extensor digitorum communicans over theintraosseous space. IM pins placed in the radius canbe retrograded out through the distal radius andthen normograded back into the proximal fragment.Badly displaced radial and ulnar fractures can usu-ally be repaired by applying an external fixator orshuttle pin in the ulna, and placing a simple intra-medullary shuttle pin in the radius. Plates can beused to repair ulnar fractures.

The HumerusHumeral fractures usually require open fixation be-cause contraction of the pectoralis and biceps brachiimuscles pulls the distal bone fragment proximally,creating a displaced fracture (Figure 42.21). A dorsalapproach is recommended for most fractures of thehumerus (Figure 42.22). This procedure avoids tran-section of the basilic vein and artery over the ventralaspect of the bone, as well as the medianoulnarnerve. However, the surgeon must cautiously incisedorsally over the midsection of the humerus to avoidthe radial nerve. Once the incision is made throughthe skin, the radial nerve should be immediatelyidentified and retracted. The humerus is exposedimmediately beneath the skin. Proximally, the mus-cles of the biceps and deltoids will overlie thehumerus. For a ventral approach, the surgeon makesan incision over the cranioventral aspect of thehumerus, taking care to avoid the medianoulnarnerve and the brachial artery and basilic vein. Theeasily separable muscles of the biceps and the tricepsconverge proximally (see Figure 42.19).

A variety of methods may be used to repair fracturesof the humerus. The choice of fixation technique isbased on the nature of the fracture, the type of pa-tient and the surgeon’s experience. External fixatorsin combination with shuttle pins or intramedullarypins are preferred for free-ranging birds. Type IIexternal fixators should be carefully applied to pre-vent pins and connecting bars from inducing softtissue trauma medially on the trunk of the animal.Threaded pins in a Type I or biplanar Type I externalfixator will reduce the chances of fixation-inducedinjuries to the animal. Stabilizing splints and ban-dages must immobilize the shoulder joint as well asthe elbow and, therefore, must be wrapped aroundthe body of the bird. Some birds may be highly intol-erant of this type of bandaging.

The CoracoidBirds can fracture the coracoid by flying into large,solid objects such as walls, windows or cars. Mini-mally displaced fractures may be stabilized success-fully by bandaging the wing to the body. Surgicalcorrection is necessary if the fracture is markedlydisplaced. A skin incision is made along the caudaledge of the furcula starting laterally and then con-tinuing medially along the lateral edge of the keel forthe first one-fifth or one-sixth of the length of the keelbone (Figure 42.23).

The superficial pectoral muscle is encountered, andan incision is made through the superficial pectoralmuscle along the caudal edge of the furcula. Thismuscle can then be elevated from the keel bone me-dially. Radiosurgery is necessary to control hemor-rhage from the clavicular artery, which supplies partof the pectoral muscle. This vessel is usually encoun-tered at the caudal midpoint of the furcula. An inci-sion or blunt dissection is used to penetrate the deeppectoral muscle. The coracoid is located immediatelybeneath the deep pectoral muscle and runs from thepoint of the shoulder at approximately a 45° angle to

FIG 42.21 Contraction of the pectoralis and biceps brachii mus-cles usually pulls the distal fragment of a humeral fracture proxi-mally. The resulting displacement of the bone necessitates openreduction and repair (courtesy of Laurel Degernes).

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the cranial aspect of the sternum.Trauma associated with a fracturedcoracoid can be significant, resultingin massive soft tissue damage andhematoma formation. Because of thelocation of the coracoid, the surgeonworks in a small, deep hole, and ra-diosurgery as well as irrigation aremandatory to keep the surgical fieldclean.

The proximal fragment of the cora-coid should be grasped and rotatedinto the incision. Following cleaningand debridement, multiple small in-tramedullary pins are introduced atthe fracture site and exteriorizedthrough the point of the shoulder.The distal fragment is rotated upinto view and cleaned, and the frac-ture is aligned. Intramedullary pinsmust be carefully normograded backinto the distal fragment. If the pinsare advanced too far caudally andpenetrate the sternum, the pins mayperforate the pericardium and theheart. This problem can be pre-vented by carefully measuring thelength of the distal fragment and us-ing this distance to advance the pins.Muscle bellies are re-apposed using asimple continuous pattern and ab-sorbable suture material. The super-ficial pectoral muscle may also besecured to the furcula. The wingshould be wrapped to the body forfive to ten days following surgery.

The Leg

Fractures of the tibiotarsus, tar-sometatarsus and phalanges arebest repaired using external fixationtechniques (Figures 42.25, 42.26).

The TarsometatarsusThe approach to the tarsometatarsusis simple because of the lack of softtissues in this area. A lateral dorsalor medial dorsal approach may beused. A straight dorsal approach isgenerally not used because of thescutes overlying this area and theextensor tendons beneath. The sur-

FIG 42.22 Dorsal approach to the left humerus. a) The skin over the dorsal humerusshould be carefully incised to avoid cutting the 1) radial nerve. The 2) humerus is visibleimmediately beneath the incision. Exposure to the proximal humerus is prevented by the3) M. tensor propatagialis and the 4) M. deltoideus. The 5) M. biceps brachii is seen onthe cranial edge of the humerus and the 6) M. triceps scapularis is located caudally. The7) radial artery runs caudal to the nerve. b) A Type I external fixator in conjunction withpositive-profile threaded pins can be used for stabilization of humeral fractures. Theconnecting bar has been raised from the skin edge for clarity purposes.


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FIG 42.23 Surgical approach to the coracoid. a) A skin incision is made along the caudal edge of the 1) clavicle starting laterally andcontinuing medially along the lateral edge of the keel. b) The 2) pectoralis muscle is incised along the caudal edge of the clavicle and the3) coracoid can be identified beneath the deep pectoral muscle coursing at a 45° angle to the cranial aspect of the sternum. c) Multiple,small intramedullary pins are passed retrograde out the cranial part of the shoulder. The pins are then carefully passed normagrade backinto the distal fragment taking care not to have the pins pass through the caudal end of the coracoid and into the heart. 4) retractors 5)keel 6) left brachiocephalic trunk 7) aorta 8) scapula 9) heart and 10) liver.

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geon should be aware of the concave nature of thecaudal aspect of the tarsometatarsus (Figure 42.25).A groove, which houses the flexor tendons of the footas well as the dorsal metatarsal artery, runs dor-somedially along with the vein and should be avoidedwhen approaching the tarsometatarsus.

Any number of fixation methods may be utilized forfractures in this area (Figure 42.26). However, exter-nal fixators are ideally suited, and Type II configura-tions are easy to apply and provide excellent stability.If IM pins must be used, they are generally intro-duced through the fracture and exteriorized in a

FIG 42.24 Overview of important surgical anatomy of the leg. a) Lateral view and b) Medial view.

1) M. iliotrochantericus caudalis2) M. iliofibularis3) M. puboischiofemoralis pars lateralis4) M. flexor cruris lateralis pelvis5) M. flexor cruris medialis6) M. caudofemoralis7) ischium8) pubis

9) M. gastrocnemius lateral head10) M. flexor digitalis II11) M. flexor digitalis III12) M. fibularis longus13) M. tibialis cranialis14) M. extensor digitorum longus15) dorsal metatarsal artery and vein16) M. iliotibialis lateralis17) M. iliotabialis cranialis

18) M. femorotibialis medius19) M. iliotrochantericus cranialis20) M. iliotibialis lateralis21) femoral artery and vein22) M. ambiens23) M. femorotibialis internus24) M. puboischiofemoralis pars medialis25) M. flexor cruris medialis

26) M. gastrocnemius medius27) M. flexor digitorum longus28) M. gastrocnemius lateralis29) M. flexor hallucis longus30) M. fibularis longus31) superficial metatarsal vein32) M. obturatorius medialis33) ischiatic nerve34) foramen acetabuli


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retrograde fashion laterally or medially to the joint,then normograded back into the distal fragment.Small plates may also be used; however, there arescant soft tissues or skin in this area that can be usedto cover the plate.

The TibiotarsusA skin incision over the craniomedial aspect of thetibiotarsus provides access to the distal two-thirds ofthe underlying bone (Figure 42.27). The medial bellyof the gastrocnemius muscle may have to be re-tracted from the cranial tibial muscle and fibularislongus craniolaterally to achieve access to some frac-tures. The cranial tibial artery, which runs over themid to distal tibiotarsus in a craniolateral position,should be avoided when making this approach.

External fixators are ideally suited and easy to applyin this area. IM pins may be introduced from thetibial crest and normograded down through theproximal and then into the distal fragments. Thispositioning prevents the pin from penetrating thestifle. Plates may be used in midshaft closed frac-tures. External fixation can be used to repairmetaphyseal fractures by placing stabilizing pins onboth sides of the affected joint.

The FemurThe lateral approach to the femur isinitiated by making a craniolateralskin incision (Figure 42.28). Thegreater trochanter proximally andthe stifle joint distally can be used aslandmarks. The cranial and caudalbellies of the iliotibialis muscle areseparated using blunt and sharp dis-section. The iliofibularis muscle islocated caudally. With this approach,the femorotibialis medialis musclewill be located craniolateral and ven-tral to the pubo-ischio-femoralismuscle will be located caudally. Dis-tally, a branch of the lateral genicu-lar artery may require attentionwhen working around the epicon-dyles and condyles.

Branches of the femoral artery maybe encountered in the cranial proxi-mal region of the femur. However,the femur is generally easy to ap-proach except in those species thathave a well developed femorotibialismedialis muscle that originates onthe lateral aspect of the femur (eg,

Anseriformes). In these species, the muscle is tran-sected and elevated cranially and caudally to exposethe femur.

A variety of fixation methods may be used for femoralfractures. Plates provide excellent stabilization espe-cially in closed fractures. Type I or biplanar externalfixators may be used alone or in combination withintramedullary pins. IM pins are passed through thefracture site and retrograded out through the greatertrochanter laterally and then normograded backthrough the distal fragments. Shuttle pins are alsoideally suited for this area.

Some surgeons have described a medial approach tothe femur (Figure 42.29).3,16 With this procedure,care must be taken to avoid the ischiatic nerve, ar-tery and vein, which lie caudomedially. The bone isapproached by separating the pubo-ischio-femoralismuscle medially. IM pins can be successfully used torepair proximal and metaphyseal fractures of thefemur.21,41 Retrograde insertion through the trochan-teric fossa and normograde insertion from the sameanatomic area can be accomplished.

FIG 42.25 Type II external fixators are ideal for repairing tarsometatarsal fractures. Theclinician should be aware of the concave nature of the tarsometatarsal bone. 1) dorsalmetatarsal artery 2) M. fibularis longus 3) M. extensor digitorum longus 4) M. extensorbrevis digiti IV 5) M. extensor hallicus longus 6, 7) M. flexor digiti II, III, IV and 8) M.gastrocnemius.

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Dome Osteotomy

Several techniques have been described for correct-ing angular limb deformities including transverse,oblique, wedge and dome osteotomies. Dome osteoto-mies have been successfully used to correct angularlimb deformities in Psittaciformes, Falconiformesand Strigiformes, and offer several advantages overother osteotomy techniques. These include ease ofplanning and implantation, maintenance of maxi-mum bone length and maximum bone-to-bone con-tact to facilitate healing. In addition, the dome osteo-tomy technique allows three-dimensional correctionof the deformity while ensuring bone-to-bone contact

in all three planes. This technique can also be usedto successfully repair fractures that have healed,producing an incorrect bone angle.

The procedure is planned from a tracing of a radio-graph of the affected limb. The radiographic viewthat indicates the most severe angular deformityshould be used for planning the procedure. Lines aredrawn sagittally through the center of the distal andproximal ends of the bone. The point where the twolines intersect is the location for the dome osteotomy.The osteotomy is performed by using a drill to makea series of small holes in a half-circle fashion at theosteotomy site. The holes are then connected using ahigh-speed air drill and a side cutting bit. The distalbone segment can then be rotated freely in the proxi-mal segment to allow proper bone alignment.42 Ap-propriate fixation, generally an external fixator, isthen used to stabilize the fracture during healing.Radiographic findings in birds suggest that whenproperly applied, a dome osteotomy site will undergoprimary bone healing with minimal to no callus for-mation (Figure 42.30).

Repair of Luxations

Luxations have been infrequently reported in birds.Those that have been reported usually involvecoxofemoral luxations secondary to a companion birdgetting a leg trapped in enclosure accessories or as aconsequence of struggling during restraint. Luxa-tions of the elbow are probably the most commonluxation in free-ranging raptors and are the result oftrauma to the distal wing while in flight. Repairrequires reduction of the luxation and stabilization ofthe joint. The sooner the luxation is detected, thebetter the chances for reduction without secondaryjoint damage.

Femoral head luxations are generally craniodorsal tothe acetabulum. Open reduction may be successful inrepairing acute cases. A femoral head osteotomy hasbeen recommended for repair of chronic luxations ofthe hip. Coxofemoral luxations may be approachedlaterally or medially for stabilization. Spica-typesplints are recommended, as well as supporting su-tures, which are placed from the greater trochanterto the ilium and to the ischium. These sutures, usu-ally of nonabsorbable materials, support the reducedhip in its normal location and are recommended inthose avian species with a gliding hinge-typecoxofemoral joint (noncursorial species such as mostpsittacine birds and raptors). It is important to re-member that some cursorial species of birds (eg,

FIG 42.26 Type II external fixators are ideal for repairing tibio-tarsal or tarsometatarsal fractures. A recently imported MilitaryMacaw was presented with an open comminuted fracture of thedistal tibiotarsus. The fracture was reduced through an openapproach and stabilized using an external fixator. Two pins wereplaced in the large proximal fracture segment, one pin was placedin the small distal fracture segment and a pin was placed in themetatarsal bone, with the joint in a normal flexed position toensure stability of the fracture. The bird was using the limb within24 hours after surgery and healing was uneventful. The medialside of the KE apparatus was removed in three weeks, and theentire KE apparatus was removed six weeks after surgery.


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ratites), have a ball and socket-type coxofemoral jointand these sutures would not be appropriate.

Elbow luxations in raptors usually result in a straightcaudal or dorsocaudal displacement of the ulna. Iftreated early, closed reduction of these luxations canbe made and then supported with external fixators orbandages. In one report, five of nine raptors withelbow luxations were successfully returned to thewild following closed reduction and support with ex-ternal fixators or bandages for seven to ten days.

Luxations of the shoulder have also been reported inraptors. These are usually accompanied by an avul-sion fracture of the ventral tubercle of the proximalhumerus. These can be stabilized by application of afigure-of-eight bandage to immobilize the wing to thebody for 10 to 14 days. A surgical approach may bewarranted to reduce and reattach the ventral tuber-cle with wires or lag screws. It is important to notethat luxations do not necessarily suggest a hopelessprognosis for return to complete function, particu-larly if addressed soon after the injury occurs.

The collateral ligaments of the knee may be damagedfollowing many traumatic events. A positive drawersign is characteristic. Techniques used to repair col-lateral ligament damage in mammals can also beused for birds.

Repair of the Beak

A healthy beak is critical to the everyday survival ofa bird, and minor injuries to this tissue can be seriousdepending upon the degree of associated soft tissuedamage. Initially, therapy for any beak injury shouldbe provided to control hemorrhage, maintain nutri-tional support and prevent secondary infection. Sev-eral approaches may be used to correct these injuries,and the therapeutic plan is chosen based upon thesize of the patient and the nature of the fracture.Birds with beak injuries that result in defects canalso readily adapt to soft diets. Prosthetic beak de-vices require continuous replacement as the beakgrows, and must be carefully monitored to preventbacterial or fungal infections.

FIG 42.27 Medial approach to the tibiotarsus. a) A skin incision(dotted line) is made over the craniomedial aspect of the bone. b)The 1) medial belly of the gastrocnemius can be retracted from the2) cranial tibial muscle and 3) fibularis longus to achieve betteraccess to the fracture site. The 4) cranial tibial vessels will be seencoursing on the cranial margin of the tibiotarsus.

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FIG 42.28 Lateral approach to the femur. a) A skin incision is made from the greater trochanter to the stifle joint as needed. The 1) cranialand 2) caudal bellies of the iliotibialis muscles are separated, using blunt dissection. b) The 3) M. iliotibialis cranialis, 4) M. femorotibialisexternus, 5) M. iliofibularis and 6) M. pubo-ischio-femoralis will be in view. c) The 7) M. femorotibialis medalis is seen on the cranial edgeof the femur.


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FracturesMandibular fractures are the most common injury andshould be addressed in two stages: repair of the bone,

and repair and realignment of thekeratinized beak. Fractures throughthe beak will not heal side-to-side.Forces encountered by the beak mustbe neutralized or they will be trans-ferred to the underlying bone andinterfere with healing (Figure 42.31).

Depending upon patient size and thelocation of the fracture, pins, wires,cements, screws and plates may beuseful in repairing mandibular frac-tures. For most smaller birds, hypo-dermic needles and cerclage wiresare useful. The primary goals are re-alignment and stabilization of thefracture site. Pins and hypodermicneedles may be inserted into thebody of the mandible, antegradedacross the fracture site from the ros-tral point of the beak, and stabilizedwith cerclage wires (plus or minuscements) (Figure 42.32).

Once the fracture is repaired, softtissue injuries must be treated. If theinjury is of a degloving type, everyattempt should be made to reapposethe displaced skin. Tissue glues areuseful for facilitating this repair. Ifglues are not applicable, the fracturesite should be dressed with a self-ad-herent wet/dry type dressing.g

Fractures of the upper beak are gener-ally more difficult to manage due tothe presence of small bones and thekinetic nature of the maxilla. Thesefractures frequently involve the quad-rate and jugal bones, which are thinstructures that are difficult to immobi-lize. The use of small hypodermic nee-dles is usually necessary to facilitaterepair, but their effectiveness is lim-ited. Healed fractures often result inbeak abnormalities such as lateral de-viation of the maxillary beak.

Beak DeformitiesBeak defects that require repair mayoccur secondary to trauma, nutri-

tional deficiencies or congenital abnormalities. Thebeak is constantly growing and any prosthesis that isapplied will migrate and loosen over time. The beak

FIG 42.29 Medial approach to the femur. 1) femoral artery, vein and nerve 2) M. femoroti-bialis medius 3) M. iliotibialis 4) M. ambiens 5) iliotibialis cranialis 6) M. femorofibialisinternus and 7) M. pubo-ischio-femoralis medialis.

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is similar in structure to a hoof, withsheets of protein overlying a substan-tial vascular supply and bone. Thekeratin layers of the bone can regener-ate only if the underlying vascular bedis viable. If the vascular tissue is de-stroyed, a permanent defect will be pre-sent in the beak.

Two common defects in psittacine neo-nates are scissors beak (lateral devia-tion of the upper beak) and mandibularprognathism. The etiology of theseproblems is only speculative. Ifmandibular prognathism is recognizedearly, it can be corrected by applyinggentle outward pressure to the beak for

ten minutes, six to eight times daily. The same tech-nique can be used to correct some early cases ofscissors beak. If cases are allowed to progress, theymust be corrected using various beak prostheses orsurgical techniques to redirect the forces applied tothe beak and its underlying bones.

Scissors BeakA severe case of scissors beak can prevent the pre-hension of food and will cause abnormal wear on bothsides of the gnathotheca. The gnathotheca on theside of the deviation will wear excessively, and thegnathotheca on the contralateral side will grow un-abated. This problem may occur in most species ofpsittacine birds but appears to be most common incockatoos and macaws. In poultry, scissors beak canbe caused by inappropriate egg incubation tempera-tures, fungal toxins, vitamin D3 toxicosis, teratogensand genetic defects.1

In theory, any slight injury to the cere or germinalbeds during early development could cause scissorsbeak (Figure 42.33). The theory that scissors beak iscaused by constantly feeding a neonate from thesame side of the mouth has been disproven.1 Keratinnormally migrates rostrally along the surface of thebeak and laterally from the vascular bed. Any changein the rate of keratin migration between these twosites, any change in the premaxilla that changes theorientation of the tip, or a malformation of the frontalbone could cause the beak to deviate laterally.

Correction procedures are designed to change theforces that direct the anterior growth of the rhino-theca (Figure 42.34). Redirected growth is achievedby applying a prosthesis to the lower beak on theaffected side or by placing pins in the calvarium and

FIG 42.30 A free-ranging Great-horned Owl neonate was pre-sented with a valgus deformity of the right tarsometatarsus. Notethe soft tissue swelling on the medial side of the foot induced byimproper ambulation. A dome-shaped cut was made in the meta-tarsus at the point of maximum deformity. The angle of the limbwas so severe that even though a dome-shaped cut was made, itappears on radiographs as an oblique osteotomy site. The osteo-tomy site was stabilized with a Type III external fixator. The birdhad full postsurgical use of the foot and was released.


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using rubber bands to apply pressure to the tip of thebeak (similar to orthodontic techniques used inhumans).

Scissors beak is easiest to repair in a young birdbecause the bones and beak are actively remodeling.The prosthetic device must be sufficiently anchoredto the lower beak to prevent normal beak occlusionfrom dislocating the prosthesis. The keratin of thegnathotheca on the affected side is grooved with aDremel tool. The grooves should be deep enough toincrease the surface area for prosthetic attachmentbut should not be so deep as to induce hemorrhage.

The scored gnathotheca is cleaned and disinfected,and a light coat of cyanomethacrylate is applied tothe area and allowed to dry. Stainless steel or nylondental screen mesh is molded to the gnathotheca.The mesh should be extended to create a ramp thatredirects the beak tip to the midline with each bite.The ramp is covered with cyanoacrylate and

smoothed with a Dremel tool. When the defect iscorrected, the implant is removed.

BragnathismBragnathism can be repaired by placing a KE wireinto the frontal bone just caudal to the maxilla jointand caudal to the nares (Figure 42.35). A caudallydirected hook is bent into the external portion of thepin. A second pin is placed in the maxilla midwaydown the beak at the point at which the internalrotation of the maxilla is most severe. Acrylic isapplied to the area, incorporating the pins to supplyextra support. A rubber band placed between the twopins will pull the beak tip into proper apposition.When the rhinotheca is properly positioned on theouter surface of the gnathotheca, the rubber bandcan be removed. The pins can remain in place forseveral more days until it is apparent that the brag-nathism will not recur. When it is apparent that theproblem is permanently corrected, the acrylic andpins can be removed.

FIG 42.31 a) An adult Blue and Gold Macaw was presented with amalaligned beak after attempting to bite a large wooden dowel.Radiographs indicated a dislocated palatine bone dorsal and rostralto the vomer bone. b,c) The dislocation was repaired by placing a pinthrough the frontal sinus over the maxilla and pushing caudally. Thedislocation was stabilized for heal ing by placing wire sutures aroundthe suborbital arch and the jugal bone ventral to the globe. The birdreturned to normal function.

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FIG 42.32 Doyle technique for repair of a mandibular symphyseal fracture. a) The gnathotheca is scarified with a dental burr. b) Thescarified area is coated with calcium hydroxide. c) Pins are placed through the mandible and hooks are fashioned in their ends. d) Rubberbands are placed around the hooks and the hardware is coated with methylmethacrylate.

FIG 42.33 a) Scissors beak in a Hyacinth Macaw chick. b) The defect was corrected by placing a KE wire through the frontal bone and usinga rubber band to place correcting pressure on the beak tip. The upper beak was properly aligned within seven days of applying the apparatus.


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FIG 42.34 a) Scissors beak can be corrected by using pins placed through the frontal bone or by using a prosthetic device attached to thegnathotheca. b) The gnathotheca is scarified with a dental burr and cleaned and covered with a light coat of dental acrylic. c) Nylon dentalmesh is covered with dental acrylic to create a ramp that pushes the tip of the beak into proper alignment. d) The prosthesis after beingshaped with a Dremel tool.

FIG 42.35 a) Bragnathism in a cockatoo neonate before repair. b,c) Repair of bragnathism using a principle (modified Doyle technique)similar to those used in human orthodontics. A KE wire is passed through the frontal bone and hooks are fashioned in both ends. A secondpin is placed into the maxilla midway down the beak. The pin in the maxilla is supported with dental acrylic. The tip of the beak is pulledinto proper apposition using a rubber band. d) Patient after correction of bragnathism.

Products Mentioned in the Texta. Osteostim, Englewood, CO or Surgical Simplex-P,

Howmedica Inc, Rutherford, NJb. Non-sterile hoof repair material, Technont, Jorgensen Labs,

Loveland, COc. Hexcelite, Hexcel Medical Co, Dublin, CA d. Manuflex, Trade-Coop, Budapest, Hungarye. American Society of Internal Fixation cuttable plates, Synthes,

Paoli, PAf. A-508 Associated Rubber Bands, Boise Cascade Co, Chicago, ILg. DuoDerm, Convatec (Squibb), Princeton, NJ

References and Suggested Reading

1.Clipsham R: Surgical correction ofbeaks: A practical lab. Proc Assoc ofAvian Vet, 1990, pp 325-333.

2.Bennett RA, Egger EL, Histand M, et al:Comparison of the strength and hold-ing power of 4 pin designs for usewith half-pin (type I) external skele-tal fixation. Vet Surg 16:207-211,1987.

3.Black J: Biomaterials for internalfixation. In Heppenstall, RB (ed):Fracture Treatment and Healing.Philadelphia, WB Saunders Co, 1980,pp 145-146.

4.Bennett RA, Kuzma AB: Fracture man-agement in birds. J Zoo Wild Med,1991.

5.Bruse SJ, Dee J, Prieur WB: Internalfixation with a veterinary cuttableplate in small animals. Vet Comp Or-thop Trauma 1:40-46, 1989.

6.Bush M: External fixation of avianfractures. J Am Vet Med Assoc171:943-946, 1977.

7.Bush M, Montali RJ, Novak GR,et al:The healing of avian fractures: A his-tologic xeroradiographic study. J AmAnim Hosp Assoc 12:768-773, 1976.

8.Chaffee VM: Sequela into intramedul-lary fixation of the humerus in an os-prey. Vet Med Sm Anim Clin 68:892-894, 1973.

9.Coles BH: Avian Medicine and Sur-gery. London, Blackwell ScientificPublications, 1985, pp 123-164.

10.Degernes LA, Lind PJ, Olsen DE, et al:Evaluating avian fractures for use ofmethylmethacrylate orthopedic tech-nique. J Assoc Avian Vet 3(2):64-67,1989.

11.Dellman, HD, Brown EM: Textbook ofVeterninary Histology. Lea and Fe-biger, Philadelphia, 1976.

12.Elkins AD, Blass CE: Management ofavian fractures. Part 2: Pins andwires. Vet Med Small Animal Clin77:825-828, 1982.

13.Fowler ME: Ossification of long bonesin raptors. In Cooper JE, Greenwood

A: Recent Advances in the Study ofRaptor Diseases. Proc Intl Symp DisBirds of Prey, London, 1980, pp 75-82.

14.Gandal CP: Anesthetic and surgicaltechniques. In Petrak ML (ed): Dis-eases of Cage and Aviary Birds 2nded. Philadelphia, Lea & Febiger,1982, pp 304-328.

14a.Harrison GJ: Anesthesia and commonsurgical procedures. Proc AssocAvian Vet, 1990, pp 460-488.

15.Howard PE: The use of bone plates inthe repair of avian fractures. J AmAnim Hosp Assoc 26:613-622, 1990.

16.Kuzma AB: Avian orthopedics: An up-date and review of new techniques.Proc Am Assoc Zoo Vet, 1990, pp 159-162.

17. Kuzma AB, Hunter B: Avian fracturerepair using intramedullary bone ce-ment and plate fixation. Proc AssocAvian Vet, 1989, pp 177-181.

18.Kuzma AB, Hunter B: Osteotomy andderotation of the humerus in a tur-key vulture using intramedullary po-lymethylmethyacrylate and boneplate fixation. Can Vet J 30:900-901,1989.

19.Kuzma AB, Hunter B: A new tech-nique for avian fracture repair usingintramedullary polymethylmethacry-late and bone plate fixation. J AmAnim Hosp Assoc 27:239-248, 1991.

20.Leeds EB: Tibial fracture repair in adouble-waddled cassowary. J Vet Or-thop 1:21-27, 1979.

21.Levitt L: Avian orthopedics. CompendCont Ed Pract Vet 11:899-929, 1989.

22.Lind PJ, Degernes LA, Olson DE, et al:Bone cement/polypropylene rod ortho-pedic technique. J Assoc Avian Vet3(4):203-205, 1989.

23.Lind PJ, Gushwa DA, VanEk J: Frac-ture repair in two owls usingpolypropylene rods and acrylic bonecement. Assoc Avian Vet Today2(3):128-132, 1988.

24.MacCoy DM: High density polymerrods as an intramedullary fixation de-

vice in birds. J Am Anim Hosp Assoc19:767-772, 1983.

25.MacCoy DM: Techniques of fracturetreatment and their indications: Ex-ternal and internal fixation. 13thAnn Vet Surg Forum, 1985, pp 97-109.

26.MacCoy DM: Techniques of fracturetreatment and their indications: Ex-ternal and internal fixation. Proc As-soc Avian Vet, 1987, pp 549-562.

27.MacCoy DM, Collier MA: Treatment ofnonunion of the ulna in a rough-legged hawk with constant direct elec-tric current: A case report. J AmAnim Hosp Assoc 19:761-766, 1983.

28.MacCoy DM, Haschek WM: Healing oftransverse humeral fractures in pi-geons treated with ethylene oxide-sterilized, dry-stored, on-lay corticalxenografts and allografts. Am J VetRes 49:106-111, 1988.

29.MacCoy DM, Redig PT: Surgical ap-proachs to and repair of wing frac-tures. Proc 1st Intl Conf Zool AvianMed, 1987, pp 564-577.

30.Milton JL: Principles of fracture treat-ment and bone healing. 13th AnnuVet Surg Forum, 1985, pp 91-96.

31.Montali RJ, Bush M: Avian fracture re-pair, radiographic and histologic cor-relation. Proc Am Assoc Zoo Vet,1975, pp 150-154.

32.Morris PJ, Weigel JP: Mandibular frac-ture repair in a marabou stork (Lep-toptilus crumeniferus) with amethacrylate prosthesis. Proc AssocAvian Vet, 1985, pp 303-305.

33.Newton CD, Zeitlin S: Avian fracturehealing. J Am Vet Med Assoc 170:620-625, 1977.

34.Paul-Murphy J: Psittacine skull radi-ography. Proc Assoc Avian Vet, 1986,pp 81-86.

35.Putney DL, Borman ER, Lohse CL:Methylmethacrylate fixation of avianhumerus fractures: A radiographic,histologic study. J Am Anim Hosp As-soc 19:773-782, 1983.

36.Redig PT: A clinical review of ortho-pedic techniques used in the rehabili-tation of raptors. Proc Student AmVet Med Assoc Symp, 1986, pp 8-21.

37.Redig PT: A clinical review of ortho-pedic techniques used in the rehabili-tation of raptors. In Fowler ME (ed):Zoo and Wild Animal Medicine 2nded. Philadelphia, WB Saunders Co,1986, pp 388-401.

38.Redig PT: Basic orthopedic surgicaltechniques. In Harrison GJ, Harri-son LR (eds): Clinical Avian Medi-cine and Surgery. Philadelphia, WBSaunders Co, 1986, pp 596-598.

39.Redig PT, Roush JC: Orthopedic andsoft tissue surgery in raptorial spe-cies. In Fowler ME (ed): Zoo andWild Animal Medicine. Philadelphia,WB Saunders Co, 1986, pp 246-253.

40.Ritivo M: Bone and Joint X-ray Diag-nosis. Lea and Febiger, Philadelphia1955.

41.Roush JC: Avian orthopedics. In KirkRW (ed): Current Veterinary Ther-apy VII. Philadelphia, WB SaundersCo, 1980, pp 662-673.

42.Rowley J, Pshyk BW: Repair of a frac-tured humerus in a red-tailed hawk.Vet Med Small Anim Clin 76:1180-1181, 1981.

43.Sikes RL, Olds RB: Dome osteotomyfor the correction of long bone malun-ions: Case reports and discussion ofsurgical technique. J Am Anim HospAssoc 22:221-226, 1986.

44.Wahlig H, Dingeldein E: Antibioticsand bone cements. Experimental andlong term observations. Acta OrthopScand 51:49-56, 1980.

45.Williams RJ, Holland M, Milton JL, et al:A comparative study of treatmentmethods for long bone fractures.Comp Anim Pract 1(4):48-55, 1987.

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C H A P T E R S

43 PASSERIFORMES

Patricia Macwhirter

44 COLUMBIFORMES

Curt VogelHelga GerlachMait Löffler

45 GALLIFORMES

Christian SchalesKerstin Schales

46 ANSERIFORMES

John H. Olsen

47 RAMPHASTIDAE

Hans CornelissenBranson W. Ritchie

48 RATITES

James S. Stewart

S E C T I O N S E V E N

COMPARATIVEMEDICINE ANDMANAGEMENT

VII

VII

Transection of toucan beak (photo courtesy of Hans Cornelissen).

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