The "Terrible Tetrad" of the Elbow: A Case Series of Two Patients with a Rare Quadruple-Component Injury and a...

The "terrible tetrad" of the elbow - simultaneous posterior ulno-humeral dislocation, comminuted radial head fracture with dislocation, coronoid process fracture, and proximal ulnar fracture - is an injury pattern that simultaneously fulfills criteria for both the terrible triad and a Monteggia-type fracture-dislocation. Fewer than fifteen cases have been documented worldwide. We present two cases managed by different surgeons at different institutions and propose the formal adoption of the term "terrible tetrad."

Case 1: A 50-year-old male painter sustained a right-sided terrible tetrad following a fall from a ladder. Closed reduction failed. Single-stage reconstruction through a posterior approach comprised cementless radial head arthroplasty, ulnar shaft plating, and lateral collateral ligament (LCL) repair. At 5 months, the range of motion was 25-110° with a stable, congruent joint; limited recovery was attributed to rehabilitation non-compliance. Case 2: A 53-year-old woman sustained a left-sided terrible tetrad following a low-energy fall down stairs, with background hypertension and hepatitis C positivity. A combined posterior and lateral two-incision approach was used: Ulnar locking compression plate fixation, coronoid repair with FibreWire and Endobutton, uncemented radial head replacement, and LCL repair with suture anchors. Intraoperative stability and arc of motion were excellent; at 6 weeks, the patient was progressing well with supervised physiotherapy.

The terrible tetrad is extraordinarily rare and falls outside all existing classification systems. Computed tomography with three-dimensional reconstruction is essential. Systematic single-setting reconstruction - lateral column restored first - is achievable via either a single posterior or combined two-incision approach, depending on injury configuration. Supervised physiotherapy is the principal determinant of outcome.