➢ Stable anatomic fixation of the ulna is essential to the treatment of both posterior Monteggia and transolecranon fracture-dislocations of the elbow.
➢ Posterior Monteggia injuries are frequently associated with radial head and coronoid fractures as well as ligamentous injuries, and each component must be addressed during treatment.
➢ In transolecranon injuries, the proximal radioulnar relationship is typically maintained, but variant patterns can be seen.
➢ The radial head should be reconstructed or replaced in all elbow fracture-dislocations.
➢ The goal of surgical fixation in elbow fracture-dislocations is a stable reduced joint that will tolerate immediate postoperative range of motion.
The uninjured elbow is an inherently stable joint. The skeletal articulations, surrounding capsuloligamentous structures, and muscular attachments maintain stability. The primary stabilizers of the elbow are the coronoid process, olecranon, trochlea, and collateral ligaments1. Traumatic dislocations without substantial skeletal injury are considered simple and usually do not require operative repair. In contrast, complex dislocations, which are associated with fracture and may involve one or more of the primary stabilizing structures of the elbow, are unstable and typically require operative reduction and internal fixation to achieve stability.
Complex elbow fracture-dislocations follow a subluxation or dislocation event. These injuries range from ulnohumeral dislocations with radial head and coronoid process fracture (“terrible triad” injuries) to ulnar fractures with an associated injury of the proximal part of the radius, proximal radioulnar joint, radiocapitellar joint, or ulnohumeral joint. Monteggia injuries involve a proximal ulnar fracture with disruption of the proximal radioulnar joint. Transolecranon fracture-dislocations involve a proximal ulnar fracture at the greater sigmoid notch and anterior dislocation of the elbow, without disruption of the proximal radioulnar joint. Some fracture-dislocations do not follow either pattern but have features consistent with one or the other that help to guide treatment. The focus of this article is on the surgical treatment of, and current evidence regarding, these two injury patterns.
Osseous Stabilizers of the Elbow
The ulnohumeral and radiocapitellar articulations contribute to elbow stability. The proximal part of the ulna has a slight varus and anterior angulation2. The relationship of the semicircular arc of the olecranon to the trochlea is critical for maintaining elbow stability. The trochlea has a 30° anterior tilt in relation to the long axis of the humerus. The radiocapitellar articulation is important for resisting valgus stress and for preventing posterior elbow dislocation. The oval radial head deviates laterally from the long axis of the radius by 15°. The importance of the radial head to elbow stability is highlighted in the presence of an injury to the medial collateral ligamentous complex3. In the setting of an elbow fracture-dislocation with an associated radial head fracture, radial head fixation or arthroplasty should be performed to restore elbow stability. Radial head fixation can be achieved with use of small or mini-fragment screws, low-profile plates, Kirschner wires, and headless or countersunk screws. When the radial head is repaired, implants must be placed in the described nonarticular zone of the radial head to avoid impingement of proximal radioulnar joint with normal supination and pronation of the forearm4,5. Radial head arthroplasty improves stability in patients with complex elbow instability and should be performed when the radial head is not reliably reconstructable6. Repair or replacement restores the normal anatomic relationship of the radius to the capitellum as well as the normal length of the lateral collateral ligamentous complex, both of which contribute to stability following injury. Excision is not appropriate in the setting of a fracture-dislocation.
The coronoid process is a restraint to posterior dislocation and is an essential osseous stabilizer7. The coronoid process contains multiple facets: the anterior facet resists posterior forces, the anteromedial facet resists varus instability, and the base imparts rotational stability. The coronoid process is frequently involved in complex fracture-dislocations of the elbow. The coronoid process also serves as the attachment point for the anterior bundle of the medial collateral ligament (MCL) and is considered in the algorithm for surgical stabilization of complex elbow fracture-dislocations.
Ligamentous Stabilizers of the Elbow
The soft-tissue and ligamentous structures of the elbow also contribute to joint stability. The origins and insertions of the collateral ligaments as well as their predictable involvement in the various fracture-dislocation patterns must be understood in order to treat these injuries correctly. The anterior bundle of the MCL originates on the inferior surface of the medial epicondyle and inserts on the sublime tubercle of the anteromedial aspect of the ulna. The posterior and transverse bands of the MCL are considered to be capsular thickenings and are less important for preventing instability. The MCL is nearly isometric throughout a full range of motion and is the primary restraint to valgus stress3. The anular ligament has its origin and insertion on the anterior and posterior margins of the ulnar radial notch. The ligament encircles the radial head and has fibers confluent with the elbow capsule, the lateral collateral ligament (LCL) complex, and the supinator8. It functions to maintain the relationship of the proximal radioulnar joint and to prevent posterolateral rotatory instability9. The LCL complex involves the lateral ulnar collateral ligament (LUCL) and the lateral radial collateral ligament (LRCL). The LUCL originates on the lateral epicondyle and inserts on the crista supinatoris of the ulna. The fibers that originate from the lateral epicondyle and insert on the anular ligament are referred to as the LRCL. The LCL complex is the primary restraint to posterolateral rotatory instability and helps to maintain the relationship between the radial head and the capitellum. The LCL complex is closely associated with the origin of the forearm extensors. When injured, the LCL complex is avulsed from its humeral origin and commonly affects the common extensor origin as well.
Goal of Treatment of Elbow Fracture-Dislocations
The goal of treatment of elbow fracture-dislocations is a stable, reduced elbow that will tolerate early range of motion. This goal is accomplished through injury identification, appropriate treatment, and proper rehabilitation. Infrequently, these injuries can be treated without surgery when reduction can be achieved, can remain concentric, and can tolerate rehabilitation. Operative treatment, which is required in most cases, must provide stable anatomic fracture fixation and must systematically address any component leading to instability.
Posterior Monteggia Fracture-Dislocation of the Elbow
The Monteggia injury is a fracture of the proximal part of the ulna with an associated proximal radioulnar joint disruption. Monteggia originally described a lesion that involved a proximal one-third ulnar fracture with anterior dislocation of the proximal radial epiphysis10. This definition has evolved from Monteggia’s original description to encompass any fracture of the proximal part of the ulna with proximal radioulnar joint disruption. The eponym has been used incorrectly to describe many elbow fracture-dislocations that do not fit Monteggia’s description. Bado classified Monteggia injuries according to the direction of radial head displacement (Table I)11.
Jupiter and colleagues further classified Bado Type-II (posterior) Monteggia lesions into four separate subtypes (Fig. 1)12. The authors defined each lesion according to the location of the ulnar fracture. Type-IIA lesions are characterized by a fracture of the distal aspect of the olecranon and involve the coronoid process. Type-IIB lesions are metadiaphyseal fractures of the ulna that do not involve the coronoid process. Type-IIC lesions are characterized by a diaphyseal fracture of the ulna. Type-IID lesions encompass the proximal one-third of the ulna and typically involve the coronoid process and olecranon.
The incidence of each injury type varies by age. Bado Type-I (anterior) injuries are common in pediatric patients, whereas Type-II injuries predominate in the adult population13. The injury mechanism is classically described as rotation around a fixed hand with axial load to the forearm but can occur following a variety of mechanisms, including a direct blow to the upper extremity14. In the adult population, Type-II injuries typically result from lower-energy mechanisms whereas Type-I injuries result from higher-energy mechanisms and may have a higher rate of neurovascular complications15. Adult Type-II injuries are often associated with radial head fractures, coronoid process fractures, and ligament disruption, all of which must be addressed at the time of surgery (Fig. 2).
The surgical treatment of posterior elbow fracture-dislocations involves anatomic reduction of the ulna and the ulnohumeral joint. Following fracture fixation, the soft tissues are systematically addressed. Repair of the LCL complex is essential to restoration of elbow stability. The collateral ligaments are typically spared in cases of Type-IIC injuries but should be checked if any uncertainty exists. In most cases, MCL repair is unnecessary after anatomic fracture reduction and repair of the LCL complex16. Beingessner et al. described their surgical sequence for the treatment of Type-IID injuries17. The principles of treating elbow fracture-dislocations associated with a radial head and coronoid process fracture were integrated within the treatment algorithm for the Monteggia-type injury17,18. First, radial head repair or replacement is performed. If the radial head is unreconstructable, radial head arthroplasty is performed following provisional reduction of the ulnar shaft and coronoid process. This allows the radial head to be appropriately sized. Next, the ulnar shaft is reduced and is definitively fixed with a plate of appropriate size and length. After the ulnar shaft has been addressed, the coronoid process is stabilized according to the size and morphology of the fracture. Olecranon fixation is then performed with a dorsal ulnar plate. Finally, any ligamentous component of the injury is addressed. If needed, ulnar-sided cortical fragments, with their associated ligamentous attachments, are fixed first. Finally, the lateral side is addressed. If necessary, the humeral avulsion of the LCL complex (and associated soft tissues) is repaired (Fig. 3).
Unstable posterior fracture-dislocations of the elbow historically have been associated with poor outcomes19,20. Recent literature, reflecting improved injury comprehension and the use of more stable fixation, has demonstrated improved outcomes.
Some studies have involved mixed series of Monteggia injuries, with all injury types being combined into a single group. These injuries occur relatively infrequently, which is reflected in the literature. Bado Type-II injuries, which are most common in the adult population, constitute the majority of most series. Ring et al. reported their ten-year experience with forty-eight patients who had Monteggia injuries15. The majority of patients were classified as having Bado Type-II injuries (79.1%) and, of these, 68% sustained a fracture of the radial head. Forty patients reported an excellent or good result, and six of the eight patients who had an unsatisfactory (fair or poor) outcome were identified as having a Bado Type-II injury with an associated radial head fracture. That series first identified the improved outcomes associated with these injuries and identified an associated radial head fracture as a poor prognostic factor. Konrad et al. reported their ten-year experience with forty-seven patients who had Monteggia injuries and long-term follow-up (average, 8.4 years)21. The majority of patients (twenty-seven of forty-seven) had a Bado Type-II injury. Thirty-four patients (72.3%) had an excellent or good result at the time of the latest follow-up. Twelve patients required a subsequent operation, six for the treatment of ulnar nonunion. The authors concluded that a fracture of the coronoid process or radial head was a poor prognostic factor for a functional long-term outcome. Llusà Perez et al. reported the results for fifty-four patients with various Monteggia injuries, 80% of whom had a Bado Type-I or Type-II injury. More than three-quarters of the patients had an excellent or good result, and fourteen patients (25.9%) required a reoperation for various reasons14.
Jupiter et al. defined the four subtypes of Type-II lesions in their series of thirteen patients with posterior Monteggia injuries12. Ten of the thirteen patients had a fracture of the radial head; excision was performed in seven cases. Late radiocapitellar subluxation was observed in four of the eleven patients who were available for follow-up; in each case, incomplete reduction of the proximal part of the ulna was observed. Beingessner et al., in a report on their experience with Monteggia Type-IID lesions, found that these severe injuries present with predictable fracture fragments and that good functional outcomes are possible when anatomic reduction is achieved17. In their series, all patients proceeded to osseous union, with an average range of motion of 18° to 119°.
The functional outcomes for patients with a Monteggia variant injury, defined as a posterior elbow fracture-dislocation with an associated fracture of the radial neck or head, are generally worse than those for patients with a Monteggia injury without a fracture of the proximal part of the radius. Monteggia variant injuries may be prone to high rates of fixation failure and nonunion22. Each variant type is similarly defined by the direction of radial head dislocation. As noted above, many investigators have incorporated these patients into their larger series, but some have looked at them specifically. Egol et al. reported on twenty patients with Monteggia variant injuries (Types I, II and III)23. Nine patients had a fair or poor outcome, and eight patients required a secondary procedure after a mean duration of follow-up of 2.3 years. These findings highlighted the functional impairment associated with Monteggia variant injuries and the effect of a proximal radial lesion on functional outcome.
Strauss et al. reported the outcomes for patients with a posterior fracture-dislocation of the elbow and ulnohumeral dislocation24. Six patients with a dislocation of the ulnohumeral joint were compared with seventeen patients without this finding. The average range of motion and functional scores were decreased in the group of patients with an ulnohumeral dislocation, but the differences were not significant. The authors postulated that this unique injury occurred in one of two ways: (1) as a result of ulnohumeral dislocation due to a fall on an outstretched arm followed by a direct blow of the distal part of the humerus on the proximal part of the ulna or (2) as a result of a direct blow on the flexed elbow, initially resulting in a fracture of the proximal part of the ulna, followed by an ulnohumeral dislocation resulting from the momentum of the patient’s body.
Transolecranon Fracture-Dislocation of the Elbow
Anterior elbow dislocation with associated fracture of the proximal part of the ulna, but without disruption of the proximal radioulnar joint, has been termed a transolecranon fracture-dislocation of the elbow. These injuries historically have been confused or misclassified as anterior (Bado Type-I) Monteggia injuries25. This has led to their erroneous inclusion in studies addressing posterior Monteggia injuries or their exclusion from other studies because of their unique nature. The key characteristic of these injuries is that the proximal radioulnar joint is usually maintained despite disruption of the ulnohumeral articulation. As compared with other fracture-dislocations of the elbow, the elbow collateral ligaments are frequently spared. These findings, along with the direction of dislocation, define this injury (Fig. 4, A).
The recognition of this injury pattern and terminology is credited to Biga and Thomine, who recognized uniqueness of this injury26. The ulnar fracture defined the lesion type. The injury was described as being simple (Type I) or, more frequently, comminuted (Type II). Ulnar comminution, when present, was complex and frequently involved the trochlear notch or coronoid process26. Transolecranon fracture-dislocations frequently occur following a blow to the dorsal aspect of the forearm during flexion of the elbow27.
The operative treatment of transolecranon fractures focuses on restoring anatomic ulnar length, alignment, and rotation, with particular attention to the greater sigmoid notch. Restoration of the correct ulnohumeral articulation is essential to prevent radiocapitellar instability or subluxation. Ulnar stabilization is accomplished by addressing the individual parts. The olecranon and the coronoid process are components, along with the area of comminution between the coronoid process and the olecranon process (Fig. 4, B). Treatment failure has resulted from the failure to recognize or stabilize a structurally important coronoid process fracture or the failure to restore anatomic ulnar alignment25,28.
Ring et al. reported the results for seventeen patients who had sustained a transolecranon fracture-dislocation of the elbow25. Thirteen of these patients had been managed at one institution over a ten-year period of time, highlighting the relative infrequency of this injury pattern. The functional results were excellent or good for fifteen of the seventeen patients after an average duration of follow-up of twenty-five months. Other small series have addressed the clinical outcomes for patients with these injuries. Mouhsine et al. reported the results for fourteen patients who had a transolecranon injury29. Various surgical fixation methods were used. It was noted that collateral ligamentous repair or reconstruction was not required in any patient. The average duration of follow-up was 3.6 years, and ten of the fourteen patients reported an excellent or good result, with three requiring a reoperation. Mortazavi et al. reported their experience with eight patients who had sustained a transolecranon fracture-dislocation30. The average duration of follow-up was thirty-seven months. Seven of the eight patients were managed with open reduction and plate fixation, and one was managed with tension banding alone and later had a nonunion. The results in this limited series were satisfactory overall, with an average American Shoulder and Elbow Surgeons score31 of 89 points and no late instability. The average arc of motion was 115° of flexion and 158° of forearm rotation.
The relationship between the proximal parts of the radius and ulna is unaffected in the majority of anterior fracture-dislocations of the elbow, but in cases involving substantial trauma to the elbow, a proximal radioulnar joint disruption can occur in addition to the anterior fracture-dislocation of the elbow joint (Fig. 5, A). These injuries, although different from the originally described transolecranon injury, are treated according to the same principles described previously by first stabilizing osseous fragments around the proximal radioulnar joint to convert it to a stable joint (Fig. 5, B).
Restoration of stability is essential to the treatment of elbow fracture-dislocations and should be checked following surgical fixation before leaving the operating room. Early motion in a concentrically reduced elbow is not detrimental to the healing of unrepaired or unreconstructed elbow ligaments, specifically the MCL. A reduced elbow that lacks adequate motion is preferable to a stiff elbow with residual instability. The postoperative protocol for the described fracture-dislocations of the elbow is dependent on the degree of stability achieved. Our preference is to splint the arm in a position of maximum stability immediately following the operation. The splint remains in place for twenty-four to forty-eight hours to protect the wound and soft tissues. Varus stress should be avoided in the postoperative rehabilitative period to support healing. Following repair of the LCL complex, active flexion and extension in pronation is started at twenty-four to forty-eight hours. Supination in full extension is avoided. When the elbow is flexed beyond 90°, the forearm can be supinated to allow the patient to work on supination-pronation. In cases of transolecranon injuries, the collateral ligament complexes are typically uninvolved and postoperative splinting and early range of motion are guided by the intraoperative elbow stability that is observed following fixation.
Complications following the treatment of elbow fracture-dislocations are related to initial injury severity as well as to reduction quality. Failure to address an osseous or soft-tissue injury component can lead to late instability. If a stable, reduced elbow cannot be achieved, a hinged or static external fixator should be considered. The application of a hinged fixator requires accurate placement in order to maintain a concentrically reduced elbow joint during motion. Hinged fixators are not routinely used and are technically more complex to apply. Therefore, static fixators are preferred when a hinged fixator cannot be placed correctly.
The correct techniques and implants should be used for fixation. Anatomic reduction and stable fixation of the ulna are of paramount importance. A tension band wire should not be used for olecranon fixation in the majority of cases, particularly when the coronoid process is involved or there is involvement of the greater sigmoid notch. Nonrigid plates such as one-third tubular plates and reconstruction plates should be avoided as they do not provide adequate ulnar fixation.
Iatrogenic implant-related complications occur when implants are left where they will be prominent or cause impingement. The proximal part of the ulna is a subcutaneous structure, so prominent dorsal ulnar plates and screws are common and frequently unavoidable, especially in thin patients. Low-profile and anatomically contoured implants help to mitigate this problem. The implant should fit the bone as designed; plates can be modified to fit the anatomy of the patient, especially over the tip of the olecranon.
Impingement can occur at the proximal radioulnar joint when implants are placed on the radial head or neck or the proximal part of the ulna. Screws in the radial head should be countersunk. Plates and screws on the radial neck should be placed in the safe zone of the radius as described above. Finally, screws placed through dorsal ulnar plates as well as implants that are placed on the coronoid process can violate the proximal radioulnar joint. After surgery, the elbow should be taken through a full range of motion, including forearm pronation and supination, to ensure unrestricted motion without a mechanical block. An intraoperative oblique fluoroscopic image of the proximal radioulnar joint also can be used for evaluation.
The development of a postoperative infection can have serious sequelae. Initial open injuries require prompt administration of tetanus prophylaxis, appropriate intravenous antibiotics, and debridement and irrigation, even if definitive fixation will not be performed immediately. Skin incisions for debridement should be well planned and should take into account future surgical procedures. Meticulous care of the soft tissues should be performed at all times. Thin skin and subcutaneous flaps should be raised, and, to avoid soft-tissue necrosis, self-retaining retractors should not be left in the wound for long periods of time. Attention should be given to the sterile field, especially as orthogonal fluoroscopic images are made. Intraoperative antibiotics should be administered according to the proper medication schedule, and the wound should be copiously irrigated before closure. A layered closure over the proximal part of the ulna can help to decrease hardware prominence and reduce cutaneous tension.
Decreased elbow and forearm motion is common following elbow fracture-dislocations. Injuries with associated ulnohumeral or proximal radioulnar joint dislocations are also prone to inferior functional outcomes as compared with injuries without these findings. Motion should be instituted shortly after the operation; specific instructions regarding home exercises or restrictions should be reviewed with the patient. The formation of heterotopic ossification in the postoperative period is not uncommon. Operative excision of heterotopic bone following elbow trauma can result in improved function and range of motion32,33. Data regarding chemical or radiation prophylaxis against heterotopic bone around the elbow are inconclusive, with some evidence suggesting that radiation therapy actually may increase the number of adverse events following surgery34. In the acute setting, radioulnar synostosis can occur when a single deep interval is used to expose the radius and ulna. A single posterior midline skin incision can be used to approach the elbow, but separate deep intervals should be used. In many cases, the injury provides a degree of traumatic soft-tissue disruption, and this interval can be used when appropriate. When no such interval exists, we prefer to use the Kocher interval between the anconeus and extensor carpi ulnaris to approach the proximal part of the radius. The coronoid process is fixed through the radial exposure, a medial approach alongside the ulna, or a combination of both.
Late instability following operative stabilization can be a difficult problem to address. Treatment is focused on the restoration or reconstruction of each component of elbow stability35. The principles for the treatment of late instability are (1) restoration of an anterior coronoid process buttress for the trochlear notch, (2) recognition of the contribution of competent collateral ligamentous complexes in late instability, and (3) restoration of radiocapitellar contact35,36. Normal osseous and articular anatomy is restored first. In many cases, ulnar malalignment requires correction to reorient the trochlear notch. Instability also can result from an incompetent or nonanatomic trochlear notch due to malreduction of the coronoid process and/or olecranon. Correcting ulnohumeral alignment and the trochlear notch also improves the orientation of the proximal part of the radius to the capitellum. Radial head repair or arthroplasty is performed if necessary. Finally, the collateral ligaments are evaluated and are repaired or reconstructed if necessary. Frequently, the lateral complex is deficient and restoration improves stability. In cases in which these goals cannot be accomplished, ligament reconstruction or hinged external fixation can be considered. In cases of mild subluxation following the surgical treatment of elbow instability, the initiation of active elbow exercises has been shown to restore congruency to the elbow joint. The avoidance of varus stress and motion with the forearm in pronation is also recommended to decrease any strain on the LCL complex37,38.
The treatment of posterior Monteggia and transolecranon fracture-dislocations of the elbow is focused on recognizing the specific injury and sequentially addressing each component of instability. Understanding the causes of elbow instability is necessary to develop an operative plan and to be sure that injuries, including soft-tissue disruptions, are not missed. Restoring ulnar anatomic alignment and a competent trochlear notch will help to reestablish elbow stability. If necessary, the radial head is fixed or replaced. The ligamentous stabilizers of the elbow are addressed, with priority first given to the lateral side, if necessary. Early directed range of motion is started in the postoperative period with close clinical and radiographic follow-up (Table II).
Source of Funding: No external funding was utilized for this investigation.
Investigation performed at Harborview Medical Center, University of Washington, Seattle, Washington
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
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