Malunion, delayed union, nonunion Flashcards Preview

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Flashcards in Malunion, delayed union, nonunion Deck (25)
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What are major causes of delayed, absent bone healing?

poor blood supply
inadequate stabilization


What is "fracture disease"?

a general term for poor use of a limb after a fracture
1. muscle atrophy
2. joint stiffness
3. tissue fibrosis
4. pain on palpation of the fracture site
5. poor limb function


What can predispose to fracture disease?

methods that immobilize the joints but don't adequately immobilize the fracture fragments


What is quadraceps contracture?

The quadraceps musculature becomes incorporated into the fibrous tissue involving the callus--stifle fixed in extensino


What can cause quadraceps contracture?

1. complicated or delayed healing of midshaft to distal femoral fractures
2. young dogs with seemingly normal healing
3. schroederthomas splint


What are the treatments for quadraceps contracture?

1. avoidance--stabilize the fracture NOT splint, rehab
2. quadraceps release--physical rehap, surgery to free quadraceps
3. quadraceps release and elastic band placement w/ transfixation pins--flexion of stifle
4. stifle arthrodesis--fusing stifle joint in a more useful position--ok for cats, smaller dogs
5. amputation-if chronic severe


What is malunion?

1. healing of fracture in abnormal alignment (angular, rotational, axial)


Why can femur fracture cause hip luxation?

because when breaks, external rotation occurs because external rotators are stronger--can be easy to repair femur while inadvertently allowing hip to stay externally rotated


Why can femur fracture cause hip luxation?mies?

because when breaks, external rotation occurs because external rotators are stronger--can be easy to repair femur while inadvertently allowing hip to stay externally rotated


Why can bent bones slowly become straighter?

Because can remodel--Wolff;s law


What malunions can never remodel to a more normal form?



What are 7 types of osteotomies?

1. closing wedge osteotomy
2. opening wedge osteotommy
3. combination wedge osteotomy
4. oblique osteotomy
5. dome osteotomy
6. step osteotomy or step-wedge osteotomy
7. distraction osteogenesis


What is closing wedge osteotomy?

1. wedge removed from side with greater curvature--good boney contact, rapid healing, some bone length loss


What is opening wedge osteotomy?

transverse cut, open the cut to a wedge until bone realigned--no bone shortening but healings more slowly due to gap


What is combination wedge osteotomy?

cut wedge out of one side, reverse it and put in other side. not common


What is oblique osteotomy?

cut oblique, then spear point of oblique end into medullary canal of distal end--use bone plate, similar to opening wedge


What is dome osteotomy?

cut a dome then rotate one piece relative to the other--good bone contact but can only rotate the fragments in one plane. used in TPLO


what is step osteotomy/step-wedge osteotomy?

almost exclusively in young large animals--due to cuts required. good bone to bone contact, relative movement of boney fragments in two planes


What is distraction osteogenesis?

bone is cut and pieces are gradually aligned (and may be lengthened) by gradually moving them apart and into place--most commonly with circular external fixator


What is the qualification for a delayed union?

if does not heal as expect (not on way to keeling in 6-10 wees or 2-6 weeks if young)


What is the qualification for a nonunion

6-8 months


what are causes of nonunions?

1. inadequate blood supply
2. instability of fracture fragments
3. excessive distance between fracture fragments--critical gap in adults --usually twice diameter of bone at site
4. infeciton


What types of nonunion are there?

1. vascular nonunion
2. avascular nonunion


What occurs in vascular (trophic/hypertrophic) nonunion?

instability--bone cannot heal because ther eis two much motion
"elephant foot appearance"


What is the treatment for a vascular nonunion?

rigid stabilization