Bones II Flashcards

Question

What is fixation?

Answer 1

- refers to fastening something firmly in position (holding something in a fixed position) - in orthopedic surgery, fixation refers to the immobilization of the parts of a fractured bone - fixation can be external (splint or cast), internal (various metal devices, or both

Answer 2

Callus remodeling - w/ time, woven bone is replaced w/ lamellar bone, compact bone is formed in the cortex, & cancellous bone is formed in the metaphysis & diaphysis - since resorption & formation are about equal, this represents remodeling

Answer 3

- cutting cones perform osteoclastic tunneling - series of osteoclasts at the front of the cone & behind it are osteoblasts that lay down new bone

Answer 4

Callus modeling - final phase of fracture repair results in restoration of the fractured bone to its original form (size & shape) & function (or as close as possible) - specifically, callus modelling involves the reduction in size of the callus & sculpting of the bone in response to the stresses of weight bearing & muscle pull - this phase make take months to years

Answer 5

nonunion, delayed union, malunion

Answer 6

failure of the fragments of a fractured bone to heal - to become fused bone

Answer 7

- inadequate blood supply - instability (movement) - infection - presence of necrotic fragments of bone or soft tissue w/in the fracture gap - pathologic fractures rarely heal w/o intervention

Answer 8

- describes a fracture that takes longer than normal to heal - since the time required for fracture healing can be highly variable, the criteria for the diagnosis of a delayed union are also variable

Answer 9

- it is often difficult to differentiate btwn a nonunion & a delayed union - some authorities define a nonunion as a fracture that fails to display any progressive changes - usually using radiography - for @ least 3 months after the time when normal fracture healing would have occurred - others believe that a fracture that has not healed w/in 6 months of the injury will likely remain unhealed (w/o intervention) & is, therefore, defined as a nonunion

Answer 10

- (mal is a prefix meaning ill or bad) - refers to a fracture that has healed, but in an abnormal alignment (ex: results in a deformed limb or other structure) - malunions can result in a shorter limb due to the fusion of overriding fragments; axial deformities (or crooked/bent limbs); & rotational deformities (or twisted limbs)

Answer 11

- site of longitudinal growth (& sometimes growth in other directions) in endochondral bones - it's a temporary structure composed of hyaline cartilage - it's widest when growth is most rapid & becomes narrow as growth slows - growth stops when the physis is entirely replaced by bone - this is referred to as closure of the growth plate & marks skeletal maturity

Answer 12

1. physeal/growth plate fractures (Salter-Harris fractures) 2. growth retardation lattices 3. growth arrest lines 4. premature closure 5. osteochondrosis/ osteochondritis

Answer 13

- b/c the physis is composed of cartilage, it is physically weak compared to bone & can be more easily injured - since the physis is the site of longitudinal growth, injury to the physis can affect longitudinal bone growth

Answer 14

- classifies growth plate injuries, including fractures, was 1st described for humans in 1963 & has been widely accepted & applied in both human & vet med - classification groups physeal injuries into 1 of the original 5 types (or 4 additional types that are rare & have been added since) - this classification system is useful in communicating the nature of an injury & predicting prognosis - as the number associated with the type of injury increases, the prognosis for a return to a functional, straight, pain-free limb decreases

Answer 15

I - (S) - straight across (separated or slipped) II - (A) - above (or away from joint) III - (L) - lower (into joint) IV - (TE) - through everything (both/all) V - (R) - rammed (crushed)

Answer 16

- fracture through the physis of the head (caput) of the femur (ex of Salter-Harris type I fracture) is a surprisingly common lesion in Fe - some believe this condition is a traumatic fracture - most affected Fe are young (4-24 months), overweight, neutered males - histologically, the fractured physis is thickened w/ irregularly arranged chondrocytes, which gives rise to the term physeal dysplasia - pathogenesis of this condition is uncertain - however, there is some evidence that certain physes of Fe that are neutered before 6 months of age - males more common than females - remain open longer than sexually intact Fe - (the normal age at the time of closure of the proximal physis in Fe has reported to be about 9 months (or 270 days), w/ a range of 210 to 290 days) - this has led some to believe that early neutering delays the closure of the proximal femoral physis, may lead to physeal dysplasia &, as these Fe become stronger & heavier, predisposes these Fe to a "slipped" capital femoral physis - btwn 24% & 38% of affected Fe will develop bilateral fractures

Answer 17

- typically detected in aborted, stillborn, or neonatal animals - thin lines to wide bands of increased bone density (osteosclerosis) in the metaphyses, parallel to the physes (but can also be seen w/in epiphyses) - represent areas of impaired osteoclastic activity leading to the retention of LONGITUDINAL trabeculae of primary spongiosa - GRLs is a poor term b/c growth need not be retarded for the lattices to appear - THE LESION IS A FAILURE OF REMODELING - GRLs are a nonspecific change (are lesions that can be caused by a variety of insults) - a few known causes of GRLs include in utero infection of fetal calves w/ Bovine Viral Diarrhea (BVD) virus; canine distemper virus infection in growing puppies; & exposure to lead in any developing or growing animal

Answer 18

- are typically detected in young, growing animals - GALs are also linear lesions in the metaphysis parallel to the physis - however, they represent TRANSVERSE (vs. longitudinal) trabeculae of bone & are a result of a period of retarded or arrested longitudinal growth - layer or layers of transverse trabeculae are carried into the metaphysis if growth resumes - any debilitating disease of general malnutrition can retard growth & produce GALs

Answer 19

- these lesions are the consequence of a chronic, underlying disease condition, not an acute or spontaneous change - need to go looking for underlying cause (pneumonia, starvation, parasitism)

Answer 20

- closure may be partial (focal) or complete (diffuse) - if the closure is focal, it results in an altered shape of a growing bone - if the closure is complete, it results in abnormally short bones - trauma, vitamin A toxicity, manganese deficiency, & radiation injury known causes - there may be others - damage to epiphyseal vessels nourishing the proliferative zone of the physis can also cause localized physeal closure - feeding moldy cereal straw to pregnant cows has produced this lesion & a disease known as congenital spinal stenosis in western Canada

Answer 21

- THE FOCAL OR MULTIFOCAL FAILURE (OR DELAY) OF ENDOCHONDRAL OSSIFICATION RESULTING IN LOCALIZED THICKENING OF HYALINE CARTILAGE - may occur at the physeal or articular areas of endochondral ossification - pain & lameness may result b/c the retained cartilage is not as stable as bone & subject to injury - clinically, osteochondrosis or osteochondritis are terms used to ID a variety of manifestations & sequelae of the presence of the thickened cartilage

Answer 22

- there appears to be multiple & interrelated factors which are associated w/ osteochondrosis & the factors at play may depend on the sp & location of the lesion - genetic, hormonal, nutritional, metabolic, & mechanical factors are all thought to be involved

Answer 23

Some forms of osteochondrosis, in certain spp, & at certain locations, are treated like specific diseases: - ununited anconeal process of Ca - is the failure of the anconeal process (a secondary center of ossification) to fuse w/ the ulna - epiphysitis or physitis (more accurate) in Eq - is a clinical term, but an inaccurate pathologic diagnosis, for a generalized disease of young horses characterized by thickening & dysplasia of physes of certain long bones - osteochondrosis of swine - was relatively common at one time but is now rare. when used in relation to Sw, osteochondrosis is a generalized condition that is most common & easily diagnosed around joints

Bones II Flashcards

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