Terrible triad of the elbow injury is difficult to manage because it is a triple injury, and it often lead to instability, contracture, re-operation, and progression to arthrosis of the elbow.16 The role of the coronoid process in instability after a terrible triad injury is very important. Most elbow instability is the result of loss of the anterior buttress if coronoid process fixation is not performed.17. Lack of full extension due to loss of the anterior buttress can lead to flexion contracture, stiffness, or re-dislocation of the elbow. Even if a coronoid process fracture without dislocation heals, incongruity of the joint is usually present resulting in progressive arthrosis of the elbow
We believe there are two reasons why many surgeons do not repair the coronoid process. First, most surgeons think fixation in Morrey type I/II coronoid process avulsion fractures is not necessary. Second, it is difficult to fix a tiny avulsed fragment. Some surgeons use dynamic ESF to keep the elbow reduced during rehabilitation. But dynamic ESF is inconvenient for patients in their daily life. According to the Morrey principle, fixation of Morrey type I/II coronoid process fractures is not necessary, but in most cases the injury is a simple fracture- dislocation without any collateral ligament injuries. In a terrible triad injury, however, a Morrey type I/II coronoid process fracture is always combined with a LUCL or MCL injury, and extreme instability is present. For this reason, we believe all injuries that occur in the terrible triad of the elbow must be repaired to obtain stability of the elbow and good functional outcomes.
There is a general belief that it is very difficult to fix the coronoid process fragment. Techniques described for coronoid process fixation include a posterior pull-out suture, suture lasso fixation, lag screw fixation, use of a precontoured locking plate, and suture anchors. Lag screw and precontoured locking plates are suitable Morrey type III larger fragments. Although the pull-out suture and suture lasso fixation techniques are suitable for type I/II smaller fragments, usually two incisions or a global posterior incision are needed, and the techniques have a steep learning curve. The suture anchors technique is a novel idea, and suitable for type I/II smaller fragments. It is also suitable for terrible triad injury via the same lateral incision to fix the fracture fragment and anterior capsule. Unfortunately, it is often a dilemma as to have the elbow in flexion or extension when the knot is slid to compress the fragment in the traditional suture anchor technique. Manipulation is relatively easy when the elbow is extended, but it is difficult to attach the fragment to the original fracture site. When the elbow is extended and the knot is slide we have always found the fragment floating above the coronoid base on postoperative radiographs because of brachialis traction, although the elbow is stable. On the other hand, putting the elbow in flexion will counteract brachialis traction, but manipulation is more difficult and the fragment is still found floating on postoperative radiographs (Fig. 4, A). However, the method we have described for the suture anchors of type I/II coronoid process avulsion fractures in terrible triad injuries requires only one incision via a lateral Kocher’s approach. If additional access to the coronoid is needed, anterolateral dissection may be performed by elevating the wrist and common digital extensors, as well as the supinator.
Our single pulley double-strand suture tie method is different from a traditional anchor suture tie. Two independent knots form two points to compress the avulsed fragment, and this resists the brachialis traction force that occurs with the traditional suture technique. Our technique uses one anchor with two pairs of knots that form a square to reduce and compress the avulsed fragment. Compression in the shape of a square is better than two points because it creates a broad area of bone contact. Of course, the “double pulley” technique18 is stronger than our method with respect to rotator cuff repair, but the coronoid process base is too small for 2 screws. Based on our experience with our technique, however, 1 screw is enough for fixation and to resist the pull of the brachialis. With our technique, radial head fracture reduction and fixation, or replacement, and LUCL repair can be performed after coronoid process fixation using the same incision. None of our patients required a medial side approach, or dynamic ESF assist after surgery.
In our experience, terrible triad patients should receive surgery as soon as possible because the procedures are more difficult once soft tissue swelling occurs. We prefer the injury to surgery time to be less than 8 hours. It is difficult to repair the coronoid process using the traditional suture tie technique with an anchor suture when there is soft tissue swelling due to a delay in surgery. In past cases, 2 incisions are typically used, a lateral and an anteromedial approach. However, our method can be performed with only one incision (lateral approach) even if there is soft tissue swelling.
In conclusion, the single pulley double-strand suture tie method using a suture anchor is a less invasive and simpler fixation method for the repair of coronoid process fractures in patients with terrible triad of the elbow injuries. We believe all terrible triad injury patients should have coronoid process fixation to achieve optimal outcomes.