Terrible Triad of the Elbow

Question 1

What are the three components of the terrible triad of the elbow?

Answer 1

1) radial head fracture
2) coronoid fracture
3) elbow dislocation, often posterolateral with LCL injury

Question 2

What is the injury mechanism a/w a terrible triad of the elbow?

Answer 2

Fall on elbow with valgus, axial and posterolateral rotatory stress; structures fail from lateral to medial (LCL usually ruptured, MCL last to fail); Circle of Hori

Question 3

Where does the anterior bundle of the MCL of the elbow insert?

Answer 3

Anteromedial facet of the coronoid process (sublime tubercle); 18.4mm from the tip of the coronoid
The LCL inserts on supinator crest distal to lesser sigmoid notch

Question 4

How are terrible triad elbow injuries managed?

Answer 4

Most are treated with surgery

1) ORIF vs. arthroplasty for the radial head
2) Cornoid fixed with P-A lag screws vs suture
3) LCL repaired to center of capitallar curvature (usually avulses from lateral epicondyle); elbow in 90° flexion
4) MCL repaired if continued elbow instability after LCL repair and ORIF
5) If continued instability place static or hinged ex-fix
6) Immobilize in flexion and pronation to prevent posterior subluxation; if MCL and LCL repair splint in neutral

Question 5

What is the most common complication following ORIF of a terrible triad elbow injury that requires a secondary operation?

Answer 5

Elbow stiffness and loss of ROM

Question 6

In a terrible triad injury to the elbow, repair of which structure provides the most rotatory stability?

Answer 6

LCL