The 2nd edition of my biomechanics course is in the works, and whilst Im fine tuning some improvements, here's some background to what I've developed:

The FRACTAL algorithm provides a framework to systematically approach fracture evaluation and treatment using principles rooted in mechanical engineering and physics. It emphasizes an iterative process where each step builds upon the previous one to develop a robust solution tailored to each biomechanical challenge. ⬇️

#orthotwitter #orthoX #orthopedics #orthopaedics Frame
The initial step involves establishing a simplified representation of the complex biomechanical system. This includes isolating the area of interest, and defining an appropriate frame of reference. The surgeon creates a conceptual model that delineates the boundaries of the problem, akin to setting up the initial conditions for a free body diagram. This step is needed for reducing extraneous variables and focusing on the pertinent mechanical interactions within the system.

What could be easier than removing a screw? Bad technique puts you head-to-head with screw mechanics, and in the case pictured below - F_static - aka static friction or stiction… 🧵👇

#orthotwitter #orthopedics #orthopaedics Static friction is the resistance to the initiation of motion between two surfaces at rest, requiring an initial force to overcome it. Kinetic friction, on the other hand, opposes the relative motion between two surfaces that are already in motion and is lower than static friction once motion has begun.

It sounds like an easy question: "How does a screw work", but the simple screw is often mechanically abused in orthopaedics - thus i thought it worthwhile recapping what forces screws generate, and how they function in fragment fixation. #orthotwitter #orthopedics #orthopaedics In mechanical engineering terms, a screw is an inclined plane wrapped around a cylindrical shaft, converting rotational motion to linear motion. As it advances, the thread's inclined plane generates an axial force, while a combination of wedging and friction secures the screw… twitter.com/i/web/status/1…

So what exactly does Koch mean by "the medial cortex of the femur is in compression, the lateral side in tension"? and is it actually true? #orthotwitter #orthopedics #orthopaedics Koch’s principle is stolen directly from mechanical engineering. A beam placed in bending, due to the principle of equilibrium and the distribution of forces along the beam’s cross section, experiences compression on one side, whilst the other side experiences tension

Some days i regret getting out of bed
#orthotwitter I'll post these, even though theyre far from pretty. lots of reasons why this or that shouldve couldve wouldve. not something i enjoyed much. Cables doing their best where there was no tube to reconstruct. 85yo bone was dust. screw went into the best bit of the head. open to… twitter.com/i/web/status/1…

Let me take you on a journey... #orthotwitter "no, the triceps tendon was not augmented, why do you ask?"

Cerclage wires got a good wrap in 2022. Several conference presentations, a couple of posters and abstracts, and now here's a mini literature collection for @DrMarecek and myself to bath in the next time the topic comes up #orthotwitter

osteosynthesis.org/42003807-commi… pubmed.ncbi.nlm.nih.gov/35618854/
pubmed.ncbi.nlm.nih.gov/34510127/
pubmed.ncbi.nlm.nih.gov/34825927/
pubmed.ncbi.nlm.nih.gov/34435729/
pubmed.ncbi.nlm.nih.gov/32918572/
pubmed.ncbi.nlm.nih.gov/35377073/

I've got 2 patients in orbit with concomitant fibula fractures (PLC injuries) in context of tibial plateau fracture. PLC anatomy does my head in, so heres a list of what im reading. If anyone has some tips on management of these, please chime in! #orthotwitter pubmed.ncbi.nlm.nih.gov/27620470/
pubmed.ncbi.nlm.nih.gov/26535398/
pubmed.ncbi.nlm.nih.gov/33392754/
pubmed.ncbi.nlm.nih.gov/12540438/

Radial N revision follow exfix of a dist humerus fracture. Radial paresis/paraesthesia. Nerve found entirely intact, and wasn’t wrapped around the exfix pin visible immediately deep to it. The nerve turned a hard corner over the pin in flexion, hopefully it wakes up #orthotwitter

https://twitter.com/traumaticum/status/1504013110100824066

Dorsal lateral paratricipital window. Opened the lateral intermuscular septum. Humeral cortex to the right. Blue are the exfix pins. Yellow is the radial nerve. Green is the posterior cutaneous antebrachial nerve. @kangsta77 @Gnomelover1970

Quick n dirty no frills lateral tibia walkthrough. Longitudinal lateral/anterolateral extensile approach for more complex fracture constellations requiring open reduction. The big brother of the Lazy S /MIPO approach #orthotwitter Landmarks and positioning

Part 1 of a trilogy! Reconstructing a Moore 2 Schatzker IV fracture dislocation. Middle aged fall from a ladder. I’ll start with first and finals, then start a new thread with progressive intraop fluros, and lastly a third thread with clinical anatomy photos #orthotwitter Pre and post op CT forensics #1:
Coronal slice posterior third of the plateau. Not going to pretend the lateral joint surface is perfect, looks oddly wide, though condylar with is spot on. direct arthrotomy certainly looked pretty good. Don’t know where that crumb came from. Grrr