Principles of Orthopedic Surgery (2) Flashcards
Dr. Gilley
What are the goals of orthopedic surgery?
- bone union
- return to normal function
What is fracture reduction?
- reconstructing fractured bone fragments to normal anatomical configuration
OR
- restoring normal limb alignment - reestablishing normal limb length & joint alignment, maintaining spatial orientation of limb
What does fracture reduction evolve?
must overcome physiologic processes
- muscle contraction
- fracture fragment overriding
What is a closed reduction?
reducing fractures or aligning limbs without surgically exposing fractured bones
What is an open reduction?
surgical approach to expose fractured bone segments
- anatomically reconstructed and held in position with implants
What are the advantages/disadvantages of closed reduction?
What is an open reduction classified as?
limited open reduction
open but don’t touch reduction (OBDT)
What is a limited open reduction?
- less transverse fracture into position OR
- secure oblique fracture with lag screws or cerclage
- then external fixator or interlocking nail
What is an open but don’t touch reduction (OBDT)
- realigning bone and placing plate
- fracture fragments and hematoma not manipulated
What are advantages of open reduction?
What are disadvantages of open reduction?
What are indications for open reduction?
- articular fractures
- simple fractures allowing anatomic reconstruction
- comminuted non reducible diaphysial fractures of long bones - “open but don’t touch”
What are indications for closed reduction?
- greenstick and/or non displaced fractures on long bone below elbow & stifle
- comminuted non reducible diaphysial fractures of long bones treated with external fixators
What does direct reduction do?
- counteracts muscle contraction - causes segments to override, major difficulty in anatomic reduction
- manual distraction of segments - using bone-holding forceps, eventually fatigues muscles => allows reduction
How do you directly reduce transverse fractures?
applying traction, counetrtraction, and bending forces
- bone ends lifted and brought into contact
- force slowly applied to reduce bones in normal position
How do you directly reduce using a lever for a transverse fracture?
place lever between overriding bone segments - periosteal elevator or scalpel blade handle
apply pressure gently
How do you directly reduce with bone holding forceps for a longer oblique fracture?
A. Return bone segments of long oblique fracture into reduction with bone-holding forceps
B. Place pointed reduction at angle to fracture line
C. pointed reduction forceps gently closed
With reduction, what should you be careful with?
rough handling of bone causes more fragmentation
bone inspected for fissure fracture lines
What are bone segments secure with if fissure fractures are present?
cerclage wire
How do you do direct reduction with a butterfly fragment?
- reduce fragment and securing to one segment
- creates 2-piece fracture to reduce & stabilize
How are non reducible fractures handled?
managed with indirect reduction - process of restoring fragment and limb alignment
What is indirect reduction?
process of restoring fragment and limb alignment - distracting major bone segments
What is an IM pin?
pin driven normograde through proximal bone segment to fracture site
What does this depict?
indirect reduction using an IM pin
What can you use in direct reduction for tibial/radial fractures?
animal’s weight
What does this depict?
using the animal’s weight in an indirect reduction in tibial/radial fractures
What is fracture treatment planning?
What is bone grafting?
standard practice in fracture management and joint arthrodesis
What are biomaterials for bone grafting?
deminineralized bone matrix, collagen
What are the 4 Os to bone grafting?
osteogenesis
osteoinduction
osteoconduction
osteopromotion
What is osteogenesis?
ability of cells to survive transplantation and serve as a source of osteoblasts
What is osteoinduction?
ability of material to induce migration and differentiation of mesenchymal stem cells into osteoblasts - BMP
Which “O” in bone grafting involves bone morphogenetic protein (BMP)?
osteoinduction
What is osteoconduction?
- ability of material to provide scaffold (collagen) for host bone invasion
- determine speed of osteointegration
What is osteopromotion?
material that enhances regeneration of bone
- PRP
Which “O” in bone grafting involves Platelet-Rich Plasma (PRP)?
osteopromotion
What is the gold standard in bone grafting?
cancellous bone autografts
Why are cancellous bone autografts the gold standard?
provides optimal osteogenic, osteoinductive, and osteoconductive properties and not immunogenicity
When are autogenous cancellous bone grafts recommended?
when rapid bone formation is desired
- to assist healing when optimal healing not anticipated
- to promote bone formation in infected fractures
What are disadvantages of cancellous bone autografts?
What are the locations for cancellous bone autografts?
proximal humerus
distal femur
proximal tibia
ilial wing
When do you harvest cancellous bone autografts?
after fracture stabilization
before primary orthopedic procedure
How do you take a bone graft from the proximal humerus?
How do you take a bone graft from the ilial wing?
What are cortical bone autografts?
harvested where cortical bone is removed without affecting function
With cortical bone autografts, how are the grafts incorporated into the fracture site?
as a segmental graft - placed between fracture segments
as a sliding only graft - placed over fracture site
What are the advantages to using allografts?
- reduced operating time
- availability of graft
- elimination of morbidity at donor site
What are stages of cancellous bone incorporation into healing fracture
What is an autogenous graft?
superior to allogenic graft in promoting rapid new bone formation - due to osteogenic properties
What are cortical bone allografts?
- cortical bone
- frozen cortical allografts available commercially
- used for limb-sparing procedures
What is demineralized bone matrix?
from processed allograft bone
used alone or extend cancellous bone autograft
What is external coaptation?
provide patient comfort before or after surgery and decrease soft tissue damage
used as primary repair in some conditions
What is the purpose of external coaptation?
must be at least 50% reduction of segments at fracture site on 2 radiographic views
When are casts used?
only for fractures of distal limb
What are bivalve casts?
used for fractures of carpus, tarsus, metacarpal/metatarsal bones and digits
carpal or tarsal arthrodesis
