Orthopedic Trauma Basic Principles
Goals of orthopedic surgeons when fixing fractures
Reduce fractures restoring length and alignment
Fracture fixation with absolute or relative stability
Preserving blood supply and soft tissue envelope
No soft tissue envelope = little to no blood supply
Must be careful to not expose more than absolutely necessary
All for the sake of early and safe mobilization. Restoring function.
Fun fact: Ortho surgeons used to keep patients in traction beds for months while their bones healed.
There are two types of bone healing:
No callus formation. Making it clean, the osteoclasts can bore right across the fracture site during the healing process without callus formation
Forms a callus around the fracture site.
Much of orthopedic trauma surgery and fixation choice is based on what type of bone healing you want to occur.
You can choose which type of bone healing you want to occur based on the type of fixation and how much stability there is at the fracture site.
Absolute stability (no micromotion) = Primary bone healing and no callus
Relative stability (Small amount of micromotion) = Secondary bone healing and callus formation
Too much motion = Cartilage formation
You choose which type of bone healing you want based on the location of the fracture.
Joint surfaces require primary bone healing
You can’t have callus forming in and around joints as they heal!
Distal femoral fractures, pilon fractures, tibial plateau fractures…etc
Fractures where secondary bone healing can be utilized
Fractures outside of joints
Commonly used in long bone diaphyses
You can’t put every single piece back together without completely devitalizing the soft tissue envelope
Use a nail or bridge plate to span the comminution
Types of fixation
Primary healing is achieved through absolute stability (no motion)
Achieved by compression across the fracture site
Lag screws often with an antiglide plate to protect the lag screws
Secondary healing achieved through relative stability (some motion)
Most commonly achieved through
External fixation (damage control orthopedics, meaning the patient is too sick or soft tissues not amenable for definitive repair)
Traction pin and long term traction (historical method)
Used as a bridge to external fixation or a more definitive fixation
There is always non operative treatment (this method can result in a pseudoarthrosis with too much motion)
Purpose is to span a comminuted fracture site or “bridge” the site when there are too many pieces to put back together without stripping all the soft tissue away
A submuscular plate is secured so that there is relative stability of the comminuted fracture site with just enough micromotion to cause secondary bone healing
Limited Contact Dynamic Compression Plate (LC-DCP)
Too much area of compression over a portion of bone can cause necrosis, so they designed plates to have limited contact
Compression plates compress across fracture sites
Useful for when you can’t use lag screws, such as in transverse fracture patterns
Example of a compression plate
Buttress plate is applied to the side of a joint surface that wedges a piece of bone buttressing it from sliding away from the joint surface.
The screw just past the apex of the main fracture is the most important to wedge the fracture in
Notice in the example below. The joint pieces are being compressed together at the articular surface to allow for primary bone healing (despite comminution)
The lag screws in the example below are partially threaded screws used in a ‘lag by design” technique
Essentially a buttress plate that is applied to the diaphysis of bone.
This plate is placed in a way that wedges in an oblique fracture fragment so that the pieces can’t glide past each other
The screw just past the apex of the fracture is the most important, just like in the buttress plate
Lag screws are screws that compress fragments of bone together
Lag by technique
By drilling the proximal fracture fragment the same diameter as the screw diameter (called the glide hole, because the screw can glide in and out) and the distal fragment hole, the same diameter as the core diameter of the screw, the screw will pull the distal fragment compressing it into the proximal fragment
Lag by design
Partially threaded screws are placed so they compress the distal piece with the proximal piece
Load sharing devices
Relative stability with secondary bone healing (some micromotion)
Short nail example