Bone Plating Flashcards
What are the 2 types of fracture fixation?
- NON-SURGICAL: external coaptation (splinting)
- SURGICAL: external skeletal fixator, pins, wires, plates, screws
What are the goals of fracture fixation (immobilization)?
- align joints and bones to restore length
- maintain some stress on bone and permit early ambulation to promote healing
- minimize motion at fracture ends
- balance forces that promote bone healing vs. those that promote bone resorption
What is Wolff’s Law?
bone remodels based on the forces applied to it
- remodels and thickens in response to increased sustained forces
- resorbs and weakens in response to decreased sustained forces
What are 4 pros to internal/external fixation?
- variety of fixation options to promote stable repair
- can promote normal muscle/joint function during bone healing
- typically fewer rechecks than with external coaptation (except with external coaptation)
- nothing externally to monitor (except with external coaptation
What are 3 cons to internal/external fixation?
- expense to clinic and owner - requires lots of specialized equipment and inventory
- requires training for appropriate application
- may require second surgery for explantation due to infection, loose/broken implants, or irritation/rejection
What are 3 pros to external coaptation?
- limited supplies necessary for placement
- need for highly specialized training is limited
- avoids prolonged surgical procedure - diaphyseal and transverse fractures heal well
What are 5 cons ot externap coaptation?
- requires frequent rechecks and bandage changes ($$$)
- limited effective applications - only below elbow and stifle
- risk of bandage morbidity preventing continued use
- immobilized joints
- bandage sores
What are some indications for external coaptation?
- fractures below the elbow or stifle
- minimally displaced fractures
- transverse, simple, closed fractures
- non-articular fractures
- fractures expected to heal rapidly - Greenstick fractures
What are 2 approaches to internal fixation?
- open anatomic reduction/reconstruction - primary bone healing with perfect bone reconstruction and rigid fixation
- biological osteosynthesis - plates placed away from the callus, avoiding disruption of fracture hematoma —> less rigid, secondary healing
What fractures require open anatomic reconstruction?
- articular fractures
- transverse, oblique, segmental, and non/minimally comminuted
What is the open but do not touch approach to biological osteosynthesis?
fracture is surgically approached and visualized, but the fracture ends are NOT manipulated during the placement of implants
- minimal disturbance of fracture hematoma, periosteum, and blood supply
What is minimally invasive osteosynthesis? What is used for guidance?
implants are placed through incisions distant to the fracture —> fracture not approached, closed reduction
intra-operative fluoroscopy - guides implant placement and confirms fracture reduction and alignment
What is the goal of biological osteosynthesis?
return limb alignment and length to normal without disruption of fracture
What considerations are included when determining implant selection?
- fracture type and location - articular vs. metaphyseal vs. diaphyseal, comminuted vs. simple
- bone affected - forces acting on bone
- patient factors - age, comorbidities, environment, size/weight
- surgeon preference and experience
What are examples of primary and secondary implants?
PRIMARY - bone plates, interlocking nails, external skeletal fixators
SECONDARY - Kirschner wires, cerclage wire, interfragmentary screws (provide additional rigidity)
What are the 2 most common types of bone plates?
- STAINLESS STEEL - 316L iron-carbon alloy, very stiff, fails by bending
- TITANIUM - less stiff, better fatigue resistance, less reactive, expensive —> bendable, so good for growing bones
What is a dynamic compression plate (DCP)?
plate that can be used for compression, neutralization, or bridging with screw holes designed to allow screw placement that promotes compression of fracture ends
- flat surface = friction between plate and bone creates stability
How do limited contact compression plates (LC-DCPs) compare to DCPs?
decreased plate to bone contact allows for improved cortical perfusion, reduced stress concentration at screw holes, and contouring
- can also be used for compression, neutralization, or bridging
How does the structure of limited contact DCPs compare to DCPs?
contoured underside allows for stress to be more evenly distributed across the plate and less disruption of periosteal vascularity
How are locking compression plates used?
combination of holes accommodate conventional screws and locking head screws, acting as an internal fixator eliminated the need for perfect contouring
- compression, neutralization, bridging
What is the purpose of using locking plates with locking head screws?
locks in to prevent the need for plate-bone contact for stable repair = more stability with fewer screws
When are locking plates most commonly used?
minimally invasive plate osteosynthesis (MIPO)
- can use both locking and cortical screws
How do locking plates compare to conventional plates?
greater forces are required to cause pull-out screws making them better for osteoporotic bone, soft bones, and comminuted fractures