Review Question - QID 5476

This patient has sustained a terrible triad injury. He has undergone successful fixation of the radial head and coronoid fractures, but has residual posterolateral instability. The next most appropriate step in the management would be repairing the LCL in the operating room.

The step-wise principles for the operative management of terrible triad injuries include, (1) restore coronoid stability through fracture fixation or capsular repair, (2) restore radial head stability through fracture fixation or replacement with a metal prosthesis, (3) restore lateral elbow stability through repair of the lateral collateral ligament (LCL) complex (4) repair the medial collateral ligament (MCL) in patients with residual posterior instability, and (5) apply a hinged external fixator when conventional repair did not establish sufficient joint stability to allow early motion.

Pugh et al. provided a surgical protocol for elbow dislocations with associated radial head and coronoid fractures. They showed that early intervention, stable fixation, and repair would provide sufficient stability to allow motion in patients postoperatively and enhance functional outcomes. Prolonged immobilization following an acute episode of elbow instability is associated with poor results.

Ring et al. retrospectively reviewed eleven patients that underwent operative fixation of terrible triad injuries. At two year follow-up, three patients were considered to have a failure of the initial treatment. There was significant loss of elbow range of motion with an average of 92 degrees (range, 40 degrees to 130 degrees) of ulnohumeral motion.

Schneeberger et al. examined the role of the radial head and coronoid process as posterolateral rotatory stabilizers of the elbow. Excision of the radial head in an elbow with intact collateral ligaments caused a mean posterolateral rotatory laxity of 18.6 degrees (p < 0.0001) compared to 5.4 degrees in the intact elbows. Additional removal of 30% of the height of the coronoid fully destabilized the elbows, always resulting in ulnohumeral dislocation despite intact ligaments.

Figure A shows intraoperative radiographs following open reduction internal fixation of the coronoid fracture and radial head fracture.

Incorrect Answer:
Answer 1: Prolonged immobilization following an acute episode of elbow instability is associated with poor results.
Answer 2: A hinged brace would not address the residual posterolateral instability in this patient. Surgical repair of LCL +/- MCL +/- application of external fixator would be required, sequentially, until elbow stability is restored.
Answer 4: Medial collateral ligament repair is indicated in patients with residual instability after fixing the lateral collateral ligament complex.
Answer 5: Application of an elbow external fixator would be the final step in the surgical algorithm to maintain elbow stability after the medial collateral ligament is repaired.