Review Question - QID 4610

The essential lesion that results in the most instability in a terrible triad injury of the elbow is rupture of the lateral collateral ligament. Repair of this lesion results in the greatest increase in elbow rotatory stability.

The key components of a terrible triad injury are a radial head fracture, coronoid fracture, dislocation of the ulnohumeral joint and disruption of the lateral collateral ligament complex. While restoration of the bony anatomy is important for static stability, the key primary stabilizer that needs to be addressed is the lateral collateral ligament complex. In acute injuries LCL repair may be possible. In chronic injury, LCL reconstruction would need to be considered.

Forthman et al. reviewed 34 patients with an elbow dislocation, 22 of 34 of which were terrible triad injuries. Open reduction internal fixation or radial head replacement (as appropriate) along with LCL repair was completed; the MCL was not surgically addressed. Seventeen of 22 had good or excellent results, indicating that MCL repair is not necessary.

Pugh et al. discuss their surgical protocol for addressing terrible triad injuries with 28/36 of their patients obtaining good or excellent results. Their inside out protocol is described as follows: 1) coronoid fracture ORIF (capsular repair), 2) radial head fracture ORIF or replacement 3) LCL complex repair (isometric point is center of capitellum), 4) reevaluation of stability; MCL repair or hinged fixator application

Jensen et.al in cadaveric studies have demonstrated that radial head replacement alone decreases varus laxity and external rotatory laxity to 14.6 & 14.8 degrees respectively. Isolated LCL repair neutralized varus laxity, suggesting that repair of this structure was more important thatn radial head replacement for gross stability of the elbow.

Figures A & B reveal a terrible triad injury with a posterolateral elbow dislocation, comminution of the radial head and injury to the coronoid process. Illustrations A & B demonstrate the post operative images for this particular patient who underwent open reduction, radial head replacement, and LCL primary repair. A video is attached that provides an overview of the terrible triad pathology.

Incorrect Answers:
Answers 1, 2: Radial head fractures need to be addressed during management of terrible triad injuries, but critical to restoration of stability is repair of the LCL complex.
Answer 3: Capsular plication may help with the operative management, but is not considered an essential step in restoring stability
Answer 5: The majority of these injury patterns may be addressed without repair or reconstruction of the medial collateral ligament complex