Review Question - QID 217370

The lateral ulnar collateral ligament is most likely affected in this patient, which is depicted by structure B in Figure A.

Terrible triad injuries consist of an elbow dislocation, radial head/neck fracture, and coronoid fracture. Often, there is an associated ligamentous injury of the lateral collateral ligament complex. The lateral ulnar collateral ligament is the most important stabilizer and is implicated in posterolatedral rotatory instability. Patients with deficient lateral ulnar collateral ligaments complain of elbow instability when pushing out of a chair.

Pugh and McKee reviewed terrible triad injuries of the elbow. The authors described surgical techniques to treat these injuries and stated 20-135 degrees elbow arc of motion to be an excellent outcome with these injuries. They reported a 15-25% reoperation rate for stiffness, recurrent instability, and symptomatic hardware.

Camp et al. provided a technical note on posterolateral rotatory instability of the elbow. They stated subluxation of the radial head and ulna occurs in a disrupted lateral collateral ligament complex. They emphasized the use of the posterolateral rotatory drawer test in assessing for elbow instability.

Figure A is a diagram depicting and lateral and medial ligamentous structure of the elbow.

Incorrect answers
Answer 1: Structure A in Figure A is the anterior bundle of the medial collateral ligament and its injury may result in posteromedial rotatory instability.
Answer 3: Structure C in Figure A is the annular ligament and does not contribute significantly to elbow instability.
Answer 4: Structure D is the radial collateral ligament that may be affected in cases of varus instability.
Answer 5: Structure E is the posterior bundle of the medial collateral ligament and is implicated in valgus instability with elbow flexion.