Make a straight posterior incision just lateral to the olecranon tip and elevate a full-thickness subcutaneous flap over the lateral side of the elbow. Some authors advocate a lateral skin incision, with or without a separate medial incision, because of the decreased size of the skin flaps and, therefore, potentially decreased chance of skin necrosis, hematoma, or seroma development¹³. We prefer the utility of the posterior global incision as medial deep approaches and potential later reconstructive or revision procedures can all be accomplished through the same incision. Furthermore, there is a lower prevalence of injury to cutaneous nerves with a posterior approach¹³.

Regardless of the skin incision, make the deep lateral exposure through the Kocher interval between the extensor carpi ulnaris and the anconeus or (as is done more frequently) through a traumatic posterolateral defect, provided that the location of the defect does not place the radial nerve or the posterior interosseous nerve at risk (Fig. 2).

Save any loose pieces of radial head on the back table for later potential fixation or prosthetic sizing.

Use a combination of varus stress and supination to dislocate the elbow, relax the soft tissues, and facilitate access to the medial side. In this way, the deepest structure, the coronoid, can be addressed first while the more superficial structures can be treated sequentially (Fig. 3).

Due to the position of the arm, the coronoid fragment is frequently far from its base, held in position by the anterior capsular attachment and resting anterior to the distal part of the humerus (Fig. 1). Grasp the fragment with forceps and pass a heavy braided suture over the coronoid fragment and through the anterior aspect of the capsule where it attaches to this piece (Figs. 4 and 5).

Drill tunnels from the subcutaneous border of the ulna, perpendicular to the ulna and directly into the corners of the coronoid fracture base (Figs. 4 and 5). The coronoid coronal cross-section is triangular, and the suture tunnels should exit at the juxta-articular vertices of the fracture base (Fig. 5). You can drill the tunnels with an eyed Kirschner wire, which is then used to pass the sutures, or with a small drill-bit with a Hewson suture passer (Smith & Nephew) as an alternative. Use either a finger for triangulation or a drill guide similar to that employed for anterior cruciate ligament (ACL) reconstruction to direct the tunnels to the right location¹³.

Once the sutures are passed, the ulnohumeral joint is reduced and the coronoid fragment is held in position with tension on the sutures. Tie the sutures over the subcutaneous border of the ulna (Fig. 5).

Next, address the radial head. For comminuted fractures or fractures that involve the radial neck, we prefer prosthetic replacement because of the difficulties with hardware failure and impingement, in addition to data suggesting that displaced and comminuted radial head fractures are best treated with prosthetic replacement¹⁵. If you choose prosthetic replacement, you have many options. We generally use a metal, modular prosthesis designed to fit loosely in the intramedullary canal of the radius (EVOLVE Modular Radial Head System; Wright Medical Technology, Arlington, Tennessee).

More important than prosthesis type, however, is prosthetic sizing with regard to head diameter and thickness. Using a prosthesis that is too large can lead to pain and lost motion from overstuffing (Fig. 6)¹⁶. Most prostheses include a sizer where the fragments can be reassembled and the diameter can be chosen. However, the radial head is ovoid, and this method tends to guide the surgeon to the diameter of the major axis. Choose the narrower, minor axis, of the elliptical radial head to determine the size of the prosthetic radial head (Fig. 7).

The thickness of the replaced radial head is another critical factor (Fig. 8)¹¹. An implant that is too thin can lead to instability as the radial head is a stabilizer to valgus stress, which is especially important in the setting of an incompetent MCL. The more common error is to use an implant that is too thick, leading to an overstuffed radiocapitellar joint manifesting as pain, loss of motion, and capitellar wear.

Once you have chosen a trial based on the size of the excised radial head, use all available landmarks to assess the fit in situ. These indicators include alignment with the medial facet of the coronoid¹¹, an anteroposterior fluoroscopy view showing that the medial joint is congruent and not opened by an overstuffed radiocapitellar joint, and alignment with a posterolateral synovial fold that frequently lies at the margin of the native radial head¹⁷.

If you choose internal fixation, use small countersunk screws or headless compression screws (Acutrak micro screw; Acumed, Hillsboro, Oregon), with or without modular plates. Any plates or screw heads that are not countersunk need to be carefully placed in the safe zone (the portion of the radial head that does not articulate with the proximal part of the ulna) to avoid impingement with the proximal radioulnar joint. Even if this is avoided, scarring to the overlying annular ligament can limit rotation, leading to a trend toward fixation with screws alone¹³.

As the radial head is a secondary stabilizer to valgus stress, do not excise the radial head without replacement¹³.

Always repair the lateral ulnar collateral ligament. This critical ligament originates on the distal aspect of the lateral epicondyle, at the isometric point in the center of the trochlear central axis¹³. It then fans out to cover the posterior half of the radial head and insert into the supinator crest on the ulna. This shape creates a resistance to varus stress, but also to posterolateral rotatory stress as it acts as a sling to support the radial head¹³. Rupture of the ligament occurs most frequently at the origin, commonly with part of the overlying extensor origin attached¹⁸.

You can weave heavy, braided suture through just the ligament substance, or through drill-holes in the ulna. We prefer to use the ligament substance for the more commonly encountered humeral avulsions. However, if the ligament ruptures distally, pass the suture through drill-holes in the supinator crest of the ulna to gain distal purchase. In the case of a midsubstance rupture, weave sutures through drill-holes in both the ulna and the humerus. Generally the lateral ulnar collateral ligament avulses from the lateral epicondyle and we use a running, locked Kessler weave so that the two suture ends come out the ruptured proximal part of the ligament (Fig. 9).

Drill bone tunnels at the isometric point of the lateral epicondyle with a 2.0-mm drill-bit. Pass the suture up through the epicondyle of the humerus with a suture passer, and then tension the sutures with the forearm supinated. Tensioning in supination prevents overtightening of the lateral ulnar collateral ligament, which can limit forearm rotation. Tie the sutures over the bone bridge of the lateral epicondyle.

Test the stability of the elbow with the hanging arm test (Fig. 10)^10,14, by fully extending the elbow over a stack of towels placed under the upper arm and supinating the forearm to recreate the position of maximal instability⁹. The weight of the hanging forearm produces a dislocating force.

Check a fluoroscopic image to determine if the elbow remains reduced during this maneuver. Although the reliability and validity of this test have not been evaluated, we believe that if the elbow remains concentrically located while hanging in this position, it is stable and no further operative intervention is required.

Step 7 is rarely required because, if Steps 1 through 6 are followed, the hanging arm test generally reveals a stable elbow; if it does, you can proceed to Step 8. However, if instability persists, repair the MCL through a medial approach and/or apply a hinged elbow external fixator.

To approach the MCL, use a flexor-pronator muscle-splitting approach. Repair the MCL in a fashion similar to the lateral ulnar collateral ligament repair described above. Use a heavy, braided, nonabsorbable suture woven through the ligament substance with either suture anchors or bone tunnels through the middle third of the underside of the medial epicondyle, in the floor of the cubital tunnel. The repair of the MCL can be difficult as, unlike the lateral ulnar collateral ligament, the MCL is frequently disrupted in its midsubstance.

Key steps in the application of a hinged external fixator include attention to the colinearity of the elbow and fixator axes of rotation, and avoiding the radial nerve by direct visualization of the humeral pins entering the bone.

Postoperatively, immobilize the elbow in 90° of flexion and neutral pronation-supination with a posterior slab or double sugar-tong splint.

On postoperative day five, six, or seven, initiate supine, well-arm-assisted, passive range of motion exercises. These should first be done with instruction by a therapist and then continued by the patient without supervision, five times per day.

In the first three weeks, emphasize well-arm and gravity-assisted flexion. As pain and swelling subside, gradually advance the protocol to an active range of motion. Tell the patient to strictly avoid abduction of the shoulder so as not to create a varus stress on the lateral ulnar collateral ligament repair¹⁰.

If an external fixator is used, the hinge is kept static at 90° for the first three weeks; then the motion arc is gradually increased until removal at six weeks.

The coronoid lasso fixation technique has been studied for terrible triad elbow fracture-dislocations. The technique is indicated for the coronoid fracture seen in this injury setting. In 90% of cases, this is a Regan-Morrey Type-II fracture¹⁴.

The lasso technique has not been studied for Regan-Morrey Type-III fractures, but we would not hesitate to use it in cases with comminution or in which use of a screw might cause fragmentation.

While the technique may prove useful for other injury patterns, it has not been systematically evaluated for use for other types of coronoid fractures. For example, it is unclear whether it is appropriate for medial facet fractures from a varus posteromedial instability pattern. Most surgeons currently advocate a small site-specific buttress plate for a large fracture fragment of the medial facet.

Avoid neurovascular structures anterior to the coronoid.

Drilling the suture tunnels can be challenging as they need to exit at the vertices of the coronoid footprint for proper reduction. As discussed in Step 3, a finger for triangulation or an ACL drill guide can be helpful for targeting.

Each element of the pathoanatomy must be addressed sequentially.

We find that fixing the coronoid in every elbow with a terrible triad injury decreases the need for MCL repair, external fixation, and lengthy immobilization. Do you find this to be true in your practice? How often do you use an external fixator?

Do you prefer a posterior incision or a lateral incision and why?

If you are using a coronoid suture lasso, how do you prefer to target the suture holes into the coronoid base? With an ACL drill guide? Freehand? With some other method?