Working Diagnosis:
Traumatic posterolateral elbow dislocation with resulting tears of the ulnar collateral ligament (UCL), radial collateral ligament (RCL), lateral ulnar collateral ligament (LUCL), and common flexor tendon tear with partial dislocation of the ulnar nerve.

Treatment:
Given the degree of damage and elbow instability, surgical repair of the medial and lateral collateral ligaments was recommended. There were no surgical complications and he did well immediately postoperatively. After four months of elbow rehabilitation, he was cleared to return to full activity in a hinged elbow brace just prior to the start of the season.

Outcome:
The athlete returned to full contact play. However, after returning, he began to experience ulnar-sided elbow pain and laxity especially with valgus stress when maneuvering the hockey stick. He underwent MR arthrogram which revealed intact and healed ulnar and radial collateral ligaments. He continued to play using an elbow brace for stability, however he did not feel confident in his elbow and felt unable to compete at his previous level. Given his continued laxity and pain, he underwent ulnar and radial collateral ligament reconstruction with autograft palmaris tendon and allograft gracilis tendon, respectively. He then completed an elbow rehabilitation program while preparing for the start of the next season.

Author's Comments:
The elbow is a stable joint and requires a significant amount of force to cause a dislocation. Despite this, elbow dislocations are a common occurrence and are the second most common joint dislocation in adults. Posterolateral dislocation is the most common and classically involves damage to ulnar-sided elbow structures with radial involvement in more severe injuries, as seen in this case. Most are treated with reduction and immobilization. Literature has shown that less than 10% of elbow dislocations require surgical repair. When surgery is required, UCL repair has been shown to provide similar clinical outcomes and return-to-sport rates when compared to UCL reconstruction, however with a faster return to play time.

Editor's Comments:
Despite being inherently stable, the elbow joint is the most commonly dislocated joint in children and the second most common in adults.[2] The incidence is as many as 6 in 100,000 individuals during their lifetime and accounts for 10-25% of all elbow injuries. There is a predominance towards the non-dominant extremity, as seen in this case. Because of the bony anatomy, significant disruptive force must be applied to dislocate the elbow. This most commonly occurs with the elbow extended and forced into hyperextension leading to a valgus moment of instability. The continued application of force leads to instability and tearing of first the lateral ulnar collateral ligament, then joint capsule, and ultimately the medial ulnar collateral ligament. In a severe injury, the radial collateral structures can also be involved. Often times, the anterior band of the medial ulnar collateral ligament remains intact allowing for posterior dislocation. Based on the force required for this type of injury, it is important to assess for associated injuries. Commonly co-occuring injuries include radial head and neck fractures, avulsion fractures of the medial or lateral epicondyle, and osteochondral injuries. Less commonly (but more importantly), neurovascular injury can occur and must be evaluated for immediately.

In the vast majority of cases, conservative management is sufficient for treatment after the initial reduction barring any concomitant fractures. Utilizing bracing for stability allows the ligamentous injuries to heal without need for surgical intervention. Early supervised rehabilitation is important to restore normal or near-normal range of motion.

As is often the case when dealing with our higher-level athletes, we must take into account the increased stress and repetitive loads that these athletes place on their joints in the course of training and performance. With this athlete in particular, the severity is assumed to be high given that he had damage to both the ulnar and radial collateral structures. He also had multi-directional instability. Based on these factors (severity, load, high-level status) it is expected that surgical repair was pursued. Since the first ulnar collateral ligament surgery 40+ years ago, reconstruction has been the gold standard. Newer studies, however, are showing at least non-inferiority for surgical repair rather than reconstruction.

Cadaveric studies have shown that there is no statistical difference in valgus stability when comparing ulnar collateral ligament repair (suspensory fixation) to reconstruction.[3] The study by Mead and colleagues showed that the repair is comparable to reconstruction with valgus stress at all degrees of flexion and did not have a statistically significant difference in torque to failure.[3] In the study by Anvari et al, they showed that utilizing internal bracing with ulnar collateral ligament repair allowed for more rapid rehabilitation and progression through return to play protocols.[1] It is important to note that this was a preliminary study and more investigation is needed.

References:
1. Anvari A, Fathi A, Bolia IK, Piatt E, Hasan LK, Haratian A, Weber AE, Petrigliano FA. Utilization of Internal Bracing in Elbow Medial UCL Stabilization: From Biomechanics to Clinical Application and Patient Outcomes. Orthop Res Rev. 2021 Oct 19;13:201-208. doi: 10.2147/ORR.S321890. PMID: 34703328; PMCID: PMC8541765.

2. Kuhn MA, Ross G. Acute elbow dislocations. Orthop Clin North Am. 2008 Apr;39(2):155-61, v. doi: 10.1016/j.ocl.2007.12.004. PMID: 18374806.

3. Mead RN, Nelson TJ, Limpisvasti O, ElAttrache NS, Metzger MF. Biomechanical Comparison of UCL Repair Using Suspensory Fixation Versus UCL Reconstruction. Orthop J Sports Med. 2021 Sep 22;9(9):23259671211038992. doi: 10.1177/23259671211038992. PMID: 35146033; PMCID: PMC8822040.

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