External Skeletal Fixation and Coaptation

Question 1

define an external skeletal fixator (ESF)

Answer 1

and ESF is an apparatus composed of multiple transcutaneous transcortical fixation pins/wires which are incorporated into an extra corporeal frame

Question 2

list the different ESF types and the basic components used to construct them

Answer 2

1. linear: transcutaneous pins or wires attached to smooth linear connecting bars via connecting clamps (main components)
   -threaded pins are preferred due to greater resistance to axial extraction (pin pull out) and the increased stability and decreased risk of loosening/drainage they provide
   -smooth pins can be used for linear ESFs in very small animals (don’t have threaded pins that small)
2. circular: small transcutaneous WIRES placed under tension are attached to rings/arc by wire fixation bolts; rings are connected by threaded rod
3. hybrid: circular components (fixation wires, wire fixation bolts, hybrid rod) on one side of fracture and linear components (fixation pins, connecting clamps, hybrid rod- smooth and threaded) on the other side

Question 3

describe the advantages (6) of ESF

Answer 3

1. preservation of blood supply
2. high versatility: beneficial if limited bone stock for internal fixation and can get very creative pin placement versus a bone plate
3. facilitates treatment of concurrent soft tissue injuries: provides stability of bone to promote wound healing
4. easy implant removal once healed: beneficial if higher risk of infection
5. latitude to make post-op adjustments
6. economical if everything goes well/case dependent

Question 4

describe the disadvantages of ESF (7)

Answer 4

1. more maintenance
2. owner compliance is KEY and essential (clean daily, frequent rechecks)
3. can inhibit function: interfere with muscle movement
4. limits on application: preferably distal to elbow and stifle
5. risk of ESF getting caught on objects and causing additional factors
6. radiographic visualization can be challenging

Question 5

describe the indications of linear ESF (2)

Answer 5

primary OR adjunctive stabilization of
1. bones (fractures):
-high grade open/infected fractures- most common use!
-comminuted fractures with limited bone stock
-very small patients/bones
-financial constraints (if uncomplicated and rapid healing expected

2. joints:
   -tendon or ligament injuries: in adjunct use
   -arthrodeses (joint fusions): especially if wounds are present preventing internal fixation

Question 6

describe indications of circular ESF

Answer 6

LIMITED to distal extremity (below elbow and stifle, and higher and body wall gets in the way)
1. comminuted/open/infected juxat-articular fractures
2. trans-articular stabilization: tendon/ligament injuries, arthrodesis
3. select angular limb deformities: gradual correction
4. limb lengthening

Question 7

describe indications of hybrid ESF

Answer 7

CAN be placed in proximal extremities (above elbow/stifle)
1. comminuted/open/infected juxta-articular fractures
2. transarticular stabilization

Question 8

describe contraindications for ESF

Answer 8

1. when pet or owner not likely to be compliant (anxious or aggressive dog)
2. prolonged healing is expected:
   -old age, malnourished
   -open/infected/comminuted fractures: most common reason for use yes, but also take longer to heal so use internal fixation when possible!!

Question 9

describe the appropriate post-operative management for an animal with an ESF

Answer 9

1. protect ESF with bumper bandage: cast padding +/- kling gauze and vet wrap
2. clean pin tracts daily with 0.05% chlorhexidine solution and triple antibiotic
3. strict activity restriction to promote bone healing and ESF protection
4. frequent recheck appointments: more frequent at beginning to force owner compliance

Question 10

list the potential complications associated with ESF

Answer 10

1. pin tract inflammation- most common!!
   -drainage, infection, osteomyelitis
2. pin loosening/breakage
3. delayed union, malunion, nonunion
4. iatrogenic fracture through pin tracts
5. soft tissue morbidity

Question 11

what is external coaptation?

Answer 11

the use of bandages, splints, casts, or slings to aid in the stability or support of extremities

Question 12

describe indication of external coaptation

Answer 12

temporary immobilization of musculoskeletal injuries

1. preoperatively:
   -provide pain relief
   -decrease swelling
   -protect wounds
   -prevent further soft tissue morbidity
2. postoperatively:
   -provide pain relief
   -decrease swelling
   -protect wounds
3. definitive treatment:
   needs to provide sufficient stability for functional healing!!

Question 13

what injuries/scenarios are most amenable to external coaptation as definitive treatment? (6)

Answer 13

1. appropriate alignment is achievable via closed reduction
2. secondary bone healing (callus) is acceptable: non-articular fractures
3. some degree of inherent stability is present:
   -greater than or equal to 75% cortical contact or 50% overlap in both views
   -simple transverse fractures
   -ulnae/fibula intact
4. minimal/no wounds: want to avoid daily bandage changes to prevent extraneous movement
5. ability to heal quickly: young animal or simple fracture
6. good owner and patient compliance!

Question 14

describe advantages of coaptation versus surgery and disadvantages

Answer 14

advantages:
1. non-invasive
2. lower expense if all goes well

disadvantages:
1. hidden costs: bandage changes
2. time commitment
3. constant monitoring
4. limits function of limb
5. instability may result in poor or porlonged healing
6. prolonged immobilization may lead to permanent dysfunction (joint stiffness/instability, muscle contracture)
7. soft tissue complications can be severe

Question 15

describe advantages of coaptation

Question 16

explain why external coaptation is CONTRAINDICATED for the definitive treatment of distal radius and ulan fractures in toy-breed dogs

Answer 16

these animals have poor blood supply in distal radius and ulna, so have poor healing potential!

if coapted, over 80% will develop malalignment or nonunion

Question 17

list the cardinal rules of external coaptation

Answer 17

for extra-articular injuries: must immobilize the joints above and below

for articular injuries: must immobilize the bones above and below

AKA can only bandage distant to elbow or stifle, because cannot immobilize should or hip!

however, bandage is typically extended down to digits to avoid tourniquet effect

Question 18

describe Robert Jones bandage

Answer 18

1. provides tranisent support of injuries distal to elbow/stifle
2. used for initial treatment of injuries to distal extremities
3. NOT the same as a soft-padded bandage (modified robert jones)

Question 19

give materials and steps required to place a robert jones bandage

Answer 19

materials:
1. 1” medical tape
2. tongue depressor
3. COTTON ROLL
4. conforming gauze roll (kling)
5. rubberized tape (vetwrap)
6. woven cotton tape (elastikon)

steps:
1. prepare patient: sedate, clip, wound management
2. apply primary layer +/- tape stirrups
3. apply cotton roll: distal to proximal, leaving the toenails of 3rd and 4th digits visible to monitor swelling and rotation, with 50% overlap and even tension
4. apply 1-2 passes of conforming gauze with even and adequate tension (moderate compression of cotton roll of +/- 50%)
5. apply 1 pass of rubberized tape (no compression)
6. place woven cotton tape over distal end of bandage

Question 20

what is a soft padded bandage?

Answer 20

1. protects surgical incisions/wounds and provides mild compression
2. does NOT provide sufficient stability to a fracture or unstable joint unless combined with a splint

Question 21

give materials and list steps required to place a soft-padded/modified robert jones bandage

Answer 21

materials:
1. 1” medical tape
2. tongue depressor
3. CAST PADDING
4. conforming gauze roll (kling)
5. rubberized tape (vetwrap)
6. woven cotton tape (elastikon)

steps:
1. prepare the patient (sedate, clip, wound management_
2. apply primary layer +/- stirrups
3. apply cast padding: distal to proximal, leaving the toenails of the 3rd and 4th digits available, with 50% overlap and even tension, do 3-4 passes (6-8 layers)
4. apply 1 pass of conforming gauze with even and adequate tension (mild to moderate compression)
5. apply 1 pass of rubberized tape (no compression)
6. place woven cotton tape over distal end of bandage

same as robert jones, just much thinner and uses cast padding instead of cotton roll!

Question 22

describe a splint bandage

Answer 22

1. provides transient support of injuries distal to the elbow/stifle
2. can be used in adjunct to surgery (pre/post op) for days to weeks
3. can also be used as a definitive treatment method for weeks to months
4. can use custom (preferred_ or premade splint materials

Question 23

describe how to place a splint bandage

Answer 23

1. steps are the same as a regular soft padded bandage except you apply the splint over the layer of conforming gauze and secure it with a second layer of gauze
2. splint can be placed caudal or lateral
3. beware of olecranon and calcaneus! common sites for pressure sores, monitor at bandage changes

Question 24

describe a spica splint (2)

Answer 24

1. used to immobilize elbow or shoulder, provides some stability but NOT enough for fracture healing
2. most commonly used after closed reduction of a lateral elbow or should luxation

Question 25

describe a cast

Answer 25

1. used in similar situations as splint bandages (injuries distal to the stifle/elbow)
2. used less commonly than a splint bandage; provides more stability BUT has a higher risk of pressure sores
3. can bivalve: once hardened, the cast is cut/scored lengthwise into 2 pieces to give more compliance or to place a splint where you scored

Question 26

describe ehmer sling

Answer 26

1. used to prevent weight bearing and maintain hip position following closed reduction of a craniodorsal hip luxation
2. typically maintained for 2-3 weeks
3. causes animal to be prone to slipping and can also cause skin irritation; commercial velcro systems are a good alternative

Question 27

list common complications associated with coaptation (5)

Answer 27

1. bandage too loose/too tight: both can lead to pressure sores, pad AROUND protuberances, not over them
2. bandage of inappropriate length causes tourniquet effect
3. loss of joint mobility
4. insufficient stability: leads to malunion, delayed union, or nonunion
5. joint laxity or angular limb deformity: common in growing puppy/kitten

Question 28

give specific recs for bandage monitoring (4)

Answer 28

1. bandage must be kept clean, dry, and intact: cover bandage with plastic bag/bootie when outdoors, do not keep covered indoors, keep E collar on
2. monitor toes twice daily for swelling
3. bandage change every 7-14 days (if no wounds)
4. if any concerns must change bandage SAME DAY: bandage wet/soiled, slipped, swollen toes, foul smell (wounds can develop QUICKLY)

Question 29

describe the velpeau sling

Answer 29

1. used to prevent weight bearing of the thoracic limb
2. indications: non-surgical scapular fractures, after closed reduction of a MEDIAL shoulder luxation
3. typically maintained for 2-3 weeks

Question 30

describe hobbles

Answer 30

1. used to prevent splaying (abduction) of the limbs
2. thoracic limbs: used for medial shoulder instability
3. pelvic limbs: used to caudoventral hip luxations