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Acute Dislocations of the Adult Elbow
Hand Clin 24 (2008) 1–7
Acute Dislocations of the Adult Elbow E. Rhett Hobgood, MD, Sami O. Khan, MD, Larry D. Field, MD* Mississippi Sports Medicine and Orthopaedic Center, 1325 East Fortification Street, Jackson, MS 39202, USA
The rate of elbow dislocations is 6 to 13 cases per 100,000 people, and elbow dislocation accounts for 11% to 28% of all injuries to the elbow [1]. Elbow dislocations occur more frequently in males than in females. The highest incidence occurs in the 10 to 20 year age group. Approximately 60% of dislocations occur in the nondominant extremity [2]. Of elbow dislocations, 10% to 50% are sports-related, although they are not unique or common to any specific sport. Recurrent instability can be a complication. A retrospective review by Kenter and colleagues [3] demonstrated that 15% of professional football players experienced recurrent instability after an initial dislocation. Lateral collateral ligament (LCL) insufficiency, particularly common in young patients, is the essential lesion that results in recurrent instability [4].
elbow, a resultant anterior force is generated that levers the ulna out of its trochlear articulation. With continued hyperextension, the anterior capsule and collateral ligaments are subjected to significant tensile forces and ultimately failure. Additional valgus or varus forces result in lateral or medial displacement of the posterior elbow dislocation. Cadaveric studies by O’Driscoll have demonstrated that an extension and varus moment associated with elbow dislocation disrupts that lateral ulnar collateral ligament first (Fig. 2) [6]. If this force is dissipated, a simple perched dislocation ensues; however, additional force further rotates the forearm and tears the remaining anterior capsule, and finally the ulnar collateral ligament, resulting in a complete dislocation.
Relevant anatomy Mechanism Posterior elbow dislocations most commonly occur from a fall onto an outstretched hand or wrist. Mehlhoff and colleagues [5] reported a fall as the mechanism of injury in 75% of patients. Posterolateral elbow dislocations comprise over 90% of all elbow dislocations (Fig. 1). The more uncommon anterior dislocation may be caused by impact on the posterior forearm in a slightly flexed position. Exactly how these forces contribute to an elbow dislocation is still a subject of debate. As the force from a fall is transmitted to the extended
* Corresponding author. E-mail address: lfi[email protected] (L.D. Field).
Intrinsic stability of the elbow is provided by both osseous and ligamentous structures. The ulnohumeral articulation is the cornerstone of osseous stability and mobility in the flexion– extension plane. The coronoid process resists posterior subluxation in flexion. The medial facet of the coronoid imparts an osseous stability to varus stress. The radial head also provides elbow stability as a secondary stabilizer to valgus loads [7]. Most activities in athletes rely on a combination of ligamentous integrity and bony articulation to provide stability to the elbow. The medial ulnar collateral ligament (MUCL) is compromised of three major bundlesdanterior, posterior and transverse bands (Fig. 3). The anterior band provides the primary restraint to valgus stress at 30 , 60 , and 90 of flexion (Fig. 4) [8]. It originates from the anterior inferior aspect of the
0749-0712/08/$ - see front matter Ó 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.hcl.2007.11.012
hand.theclinics.com
2
HOBGOOD
et al
Fig. 1. (A) Anterior-posterior and (B) lateral radiographs demonstrating a posterolateral elbow dislocation. This pattern is by far the most common dislocation pattern.
medial epicondlyle and inserts onto the sublime tubercle of the coronoid. The posterior bundle is fan-shaped and also originates from the medial epicondyle. It inserts onto the medial margin of the semilunar notch. The lateral ligament complex consists of four components: the LCL, the LUCL (ulnar part of
Fig. 2. The ring of instability with elbow dislocations describes the progression of stresses from the lateral ulnar part of the lateral collateral ligament to the anterior capsule and finally ending with injury to the medial ulnar collateral ligament. (From O’Driscoll SW, Jupiter JB, King GJW, et al. The unstable elbow. Instr Course Lect 2001;50:89–102; with permission.)
LCL), the accessory LCL, and the annular ligament (Fig. 5). The LCL attaches to the lateral epicondyle and fans out to merge indistinguishably with the annular ligament. It functions as a varus restraint and stabilizes the annular ligament. The lateral capsule of the elbow consists of three layers: the joint capsule, annular ligament, and lateral ligament. The joint capsule is the deep layer, and the true annular ligament is the intermediate layer. The superficial layer consists of the lateral ligament, which fans out from the lateral epicondyle to attach to the anterior and
Fig. 3. The ulnar collateral ligament is comprised of three bandsdanterior, posterior, and transverse bands. (From Morrey BF, Tanaka S, An KN. Valgus stability of the elbow. A definition of primary and secondary constraints. Clin Orthop 1991;265:187–95; with permission.)
ACUTE DISLOCATIONS OF THE ADULT ELBOW
3
Fig. 4. The anterior band of the lateral collateral ligament is the primary restraint to the valgus stress at 30 to 90 degrees of flexion. It originates from the anterior inferior aspect of the medial epicondyle and inserts on the sublime tubercle. It is approximately 5 mm wide and 27 mm long. (From Morrey BF, Tanaka S, An KN. Valgus stability of the elbow. A definition of primary and secondary constraints. Clin Orthop 1991;265:187–95; with permission.)
posterior aspects of the proximal ulna [9]. The LUCL is a thickening of the capsule that attaches proximally to the lateral humeral epicondyle and distally to the tubercle of the supinator crest of the ulna [10]. The humeral attachment of the LUCL is at the isometric point on the lateral side of the elbow. The distal attachment of the ligament is deep to the fascia surrounding the
extensor carpi ulnaris and supinator muscles. Besides stabilizing the lateral aspect of the elbow, the LUCL also acts as a posterior buttress for the radial head to prevent its subluxation. Josefsson and colleagues demonstrated that all 15 patients who underwent surgical exploration after acute complete elbow dislocation demonstrated injury to both the medial and lateral ligamentous complex [11].
Classification
Fig. 5. The lateral ligamentous complex of the elbow. (From Mehta J, Bain G. Posterolateral rotatory instability of the elbow. J Am Acad Orthop Surg 2004;12,6: 405–15; and adapted from Bain GI, Mehta JA. Anatomy of the elbow joint and surgical approaches. In: Baker CI, Plancher KD, editors. Operative treatment of elbow injuries. New York: Springer-Verlag; 2001; with permission.)
Multiple classification systems have been proposed for elbow dislocations. Chronologically, elbow dislocations can be described as acute, chronic (unreduced), and recurrent. The temporal definition of chronic elbow dislocation is not defined clearly, but if a joint remains unreduced for more than 7 days, the utility of closed reduction is minimal. Anterior dislocations of the elbow without associated fractures are exceedingly uncommon. Medial and lateral dislocations are likely to be incompletely reduced posterior dislocations. Consequently, classification of simple elbow dislocations into anterior, medial, lateral, and posterior is not very useful. O’Driscoll and colleagues [6] have proposed a classification system with clinical relevance (Fig. 6). This describes a spectrum of instability, from subluxation to
4
HOBGOOD
et al
Fig. 6. The spectrum of elbow instability, from subluxation to dislocation. States 1–3 correspond with the stages of capsuloligamentous disruption as discussed earlier. (From O’Driscoll SW, Jupiter JB, King GJW, et al. The unstable elbow. Instr Course Lect 2001;50:89–102; with permission.)
dislocation. The three stages correspond with the pathoanatomical stages of the capsuloligamentous disruption. A perched dislocation is one in which the elbow is subluxed but the coronoid is impinged upon the trochlea. Evaluation It is of paramount importance that the neurovascular status of the dislocated elbow be assessed and documented before manipulation. Specifically, the status of the brachial artery and median and ulnar nerves should be determined as they are most vulnerable to entrapment during manipulation. Serial neurovascular examinations should be considered in cases in which massive antecubital fossa swelling exists or in which the patient is believed to be at risk for a compartment syndrome. If clinical signs are indicative of a compartment syndrome, emergent fasciotomies of the forearm and hand should be performed. Angiography or magnetic resonance-arthrogram may be necessary to evaluate for vascular compromise. Radiographic evaluation should include standard anteroposterior and lateral radiographs and should be obtained to determine the dislocation pattern and scrutinized for associated fractures about the elbow. If there is any concern of pending vascular compromise or compartment
syndrome, the patient should be admitted for observation. Treatment options Closed reduction for simple dislocation In a perched dislocation, an analgesic with intra-articular local anesthetic is often adequate to perform a reduction maneuver. Direct pressure is applied over the olecranon while the elbow is extended slightly and gentle axial distraction is performed. For complete elbow dislocations, closed reduction should be performed under conscious sedation in a monitored emergency department setting. This will allow for relaxation of muscle spasm such that with slow, continuous, gentle, longitudinal traction combined with gradual flexion with an anterior directed force over the olecranon, the elbow should reduce without difficulty. Some authors report hyperextension of the deformity first to unlock the olecranon, but the potential danger remains of median nerve entrapment. Repeated attempts at reduction should be avoided, as soft tissue injury and swelling can worsen. After obtaining a reduction, the elbow should be taken through a range of motion to evaluate the arc of stability. Simple dislocations usually are stable throughout a full range of motion;
ACUTE DISLOCATIONS OF THE ADULT ELBOW
however, subluxation or dislocation in extension must be ruled out. If the elbow subluxates or dislocates in extension, the forearm should be pronated fully and the stability reassessed. If forearm pronation eliminates instability in extension, a hinged brace should be applied with the forearm in full pronation. Residual instability in full extension or near full extension will necessitate an extension block. However, if an extension block of more than 30 to 45 is required, surgical repair should be considered [12]. Neurovascular status is evaluated after reduction. Postreduction radiographs should be obtained to confirm a congruent reduction. Open reduction The need for open reduction after simple, acute dislocation is uncommon. Operative intervention is required when closed reduction proves unsuccessful or is otherwise contraindicated. Radial head entrapment can occur as the head becomes entrapped in the soft tissues of the forearm or even buttonholed through the forearm fascia. Medial epicondyle fractures also can become incarcerated within the joint and prevent closed reduction. The surgical approach of arthrotomy and removal of incarcerated tissue should be tailored to the specific injury pattern. For example, radial head entrapment causing a locked elbow dislocation should be approached through a lateral Kocher approach.
5
Surgical treatment As previously stated, surgical repair should be considered if the elbow requires more than 45 of flexion to remain congruent. This is seen uncommonly in simple elbow dislocations, but it can result with high energy trauma. In this situation, the full spectrum of ligamentous and capsular disruption has occurred from lateral to medial, stripping the entire distal humerus of soft tissue. A universal posterior skin incision is used, allowing access to both the medial and lateral sides of the elbow. The avulsed lateral collateral ligament and common extensor origin are reattached to the lateral epicondyle using suture anchors. Care is taken to ensure that the repair is performed through the point of isometry of the lateral ulnar collateral ligament. Stability in extension then is evaluated. If the elbow continues to dislocate in extension, the anterior and medial soft tissue injuries must be repaired. A medial subcutaneous flap is elevated, and the ulnar nerve is transposed. The anterior capsule then is secured to the coronoid with sutures passed through drill holes into the coronoid entering from the dorsal surface of the ulna. The medial collateral ligament and common flexor origins then are repaired to the medial epicondyle using suture anchors. Stability in extension then is reassessed. If the elbow continues to dislocate, a hinged external fixator is applied (Fig. 7). Application of the hinged
Fig. 7. (A, B) The hinged external fixator is a useful adjunct in the setting of gross instability. Again, this is seen with high-energy mechanisms; often, major soft tissue trauma as well as fracture dislocations are seen. (Image provided courtesy of Stryker Orthopaedics, Mahwah, NJ; with permission.)
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HOBGOOD
external fixator will allow full unrestricted motion while maintaining a congruent reduction. Usually, the lateral soft tissue repair is sufficient to restore stability, especially in older patients. High-energy injuries in the young patient, however, can require repair of the anterior capsule, medial collateral ligament, and common flexor origin in addition to the lateral repair. Weighing the evidence Closed treatment of simple elbow dislocations in adults has demonstrated satisfactory results. Van der Ley [13] showed 80% good or excellent results in 20 adults who had simple elbow dislocations treated by closed methods. There was no long-term instability with a minimum of 5 years follow up. Some authors have advocated acute surgical repair of the medial ulnar collateral ligament and/ or the lateral collateral ligament complex following simple elbow dislocations [14]. Josefsson and colleagues [11], however, showed that no benefit was gained from acute ligamentous repair of simple dislocations when compared with closed methods. Surgical repair of medial or lateral ligament disruption rarely is indicated in the treatment of uncomplicated elbow dislocations. In the unlikely setting of persistent instability with more than 30 to 45 of flexion, however, soft tissue disruption has occurred to a degree that will require ligamentous repair as described previously. The use of the hinged elbow external fixator for uncomplicated elbow dislocations has not been evaluated critically in the literature. There are multiple studies to validate its use in the setting of complex elbow fracture dislocation, however [15,16]. The fixator does provide for a concentric reduction to be maintained while range of motion exercises are begun. The soft tissue repairs also are protected from early varus or valgus stress. Mobilization recommendations For simple elbow dislocations, the elbow is immobilized for a maximum of 5 to 7 days in slightly less than 90 of flexion depending on the degree of anterior soft tissue swelling in a posterior splint. If the elbow was stable on the postreduction examination, full unprotected motion should be started no later than 1 week after injury. If forearm pronation was required to prevent extension instability, full range of motion is
et al
allowed in a hinged brace with the forearm fully pronated. The patient may only come out of the brace for motion exercises in full pronation under the guidance of a skilled therapist. The brace is worn for 4 weeks. If an extension block was required, the block should be reduced gradually so that by 4 weeks the brace allows full motion. The brace is discontinued at 4 weeks. If surgical repair is required, the elbow is changed from a posterior splint to an unlocked, hinged brace at 1 week after surgery. The patient only is allowed out of the brace for motion exercises under the guidance of a skilled therapist. The brace is discontinued at 4 weeks. If a hinged external fixator is required, it is removed 4 to 6 weeks postoperatively.
Summary The intrinsic stability provided by the bony articulations of the elbow make recurrent instability an uncommon problem after simple dislocations. These injuries usually can be managed by closed reduction and early motion. Special attention to stability immediately after reduction is necessary to guide treatment. Protected motion in full pronation and/or with a block to full extension may be required. Although uncommonly necessary, the surgeon must be prepared for open surgical repair of soft tissue injury to restore stability.
Further readings Bucholz R, editor. Rockwood and Green’s fractures in adults. 5th edition. New York: Lippincott Williams and Wilkins; 2002. p. 921–34. Josefsson PO, Johnell O, Gentz CF. ‘‘Long-term sequelae of simple dislocations of the elbow.’’ J Bone Joint Surg Br 1984;66-A:927–30. Josefsson PO, Gentz CF, Johnell O. Surgical versus nonsurgical treatment of ligamentous injuris following dislocation of the elbow joint. J Bone Joint Surg Br 1987;69-A:605–8. Mehta J, Bain G. Posterolateral rotatory instability of the elbow. J Am Acad Orthop Surg 2004;12:405–15. Morrey BF, An KN. Articular and ligamentous contributions to the stability of the elbow joint. Am J Sports Med 1983;11:315–9. O’Driscoll SW, Morrey BF. Elbow dislocation and subluxation: a spectrum on instability. Clin Orthop 1992;280:186–97. O’Driscoll S, Jupiter J, King Graham, et al. ‘‘The Unstable Elbow.’’ J Bone Joint Surg Br;82-A(5):724–38.
ACUTE DISLOCATIONS OF THE ADULT ELBOW
References [1] Josefsson PO, Johnell O, Wendeberg B. Ligamentous injuries in dislocations of the elbow joint. Clin Orthop 1987;221:221–5. [2] Josefsson PO, Nilsson BE. Incidence of elbow dislocation. Acta Orthop Scand 1986;47:537–8. [3] Kenter K, Behr CT, Warren RF, et al. Acute elbow injuries in the national football league. J Shoulder Elbow Surg 2000;9:1–5. [4] Ring D. Fractures and dislocations of the elbow. In: Rockwood CA Jr, Green DP, Bucholz RW, et al, editors. Fractures in adults. 6th edition. Philadelphia: Lippincott Williams & Wilkins; 2006. p. 989–1049. [5] Mehlhoff TL, Noble PC, Bennett JB, et al. Simple dislocation of the elbow in adults. J Bone Joint Surg Am 1988;70:244–9. [6] O’Driscoll SW, Morrey BF, An KN. Elbow dislocation and subluxation: a spectrum of instability. Clin Orthop 1992;280:186–97. [7] Morrey BF, An KN. Articular and ligamentous contribution to the stability of the elbow in the adult. Am J Sports Med 1983;11:315–9. [8] Morrey BF, Tanaka S, An KN. Valgus stability of the elbow. A definition of primary and secondary constraints. Clin Orthop 1991;265:187–95.
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[9] Martin BF. The annular ligament of the superior radio-ulnar joint. J Anat 1958;92:473–82. [10] Morrey BF, An KN. Functional anatomy of the ligaments of the elbow. Clin Orthop Relat Res 1985;201:84–90. [11] Josefsson PO, Gentz CF, Johnell O. Surgical versus nonsurgical treatment of ligamentous injuries following dislocation of the elbow joint: a prospective randomized study. J Bone Joint Surg Am 1987;69: 605–8. [12] O’Driscoll SW, Jupiter JB, King GJW, et al. The unstable elbow. Inst Course Lect 2001;50:89–102. [13] Van der Ley J. Conservative treatment of elbow dislocations in adults. Neth J Surg 1987;39(6): 167–9. [14] Durig M, Muller W, Reudi TP. The operative treatment of elbow dislocations in the adult. J Bone Joint Surg Am 1979;61:239–44. [15] Mckee MD, Bowden SH, King GJ, et al. Management of recurrent, complex instability of the elbow with a hinged external fixator. J Bone Joint Surg Br 1998;80(6):1031–6. [16] Yu JR, Throckmorton TW, Bauer RM, et al. Management of acute complex instability of the elbow with hinged external fixation. J Shoulder Elbow Surg 2007;16:60–7.
Acute Dislocations of the Adult Elbow E. Rhett Hobgood, MD, Sami O. Khan, MD, Larry D. Field, MD* Mississippi Sports Medicine and Orthopaedic Center, 1325 East Fortification Street, Jackson, MS 39202, USA
The rate of elbow dislocations is 6 to 13 cases per 100,000 people, and elbow dislocation accounts for 11% to 28% of all injuries to the elbow [1]. Elbow dislocations occur more frequently in males than in females. The highest incidence occurs in the 10 to 20 year age group. Approximately 60% of dislocations occur in the nondominant extremity [2]. Of elbow dislocations, 10% to 50% are sports-related, although they are not unique or common to any specific sport. Recurrent instability can be a complication. A retrospective review by Kenter and colleagues [3] demonstrated that 15% of professional football players experienced recurrent instability after an initial dislocation. Lateral collateral ligament (LCL) insufficiency, particularly common in young patients, is the essential lesion that results in recurrent instability [4].
elbow, a resultant anterior force is generated that levers the ulna out of its trochlear articulation. With continued hyperextension, the anterior capsule and collateral ligaments are subjected to significant tensile forces and ultimately failure. Additional valgus or varus forces result in lateral or medial displacement of the posterior elbow dislocation. Cadaveric studies by O’Driscoll have demonstrated that an extension and varus moment associated with elbow dislocation disrupts that lateral ulnar collateral ligament first (Fig. 2) [6]. If this force is dissipated, a simple perched dislocation ensues; however, additional force further rotates the forearm and tears the remaining anterior capsule, and finally the ulnar collateral ligament, resulting in a complete dislocation.
Relevant anatomy Mechanism Posterior elbow dislocations most commonly occur from a fall onto an outstretched hand or wrist. Mehlhoff and colleagues [5] reported a fall as the mechanism of injury in 75% of patients. Posterolateral elbow dislocations comprise over 90% of all elbow dislocations (Fig. 1). The more uncommon anterior dislocation may be caused by impact on the posterior forearm in a slightly flexed position. Exactly how these forces contribute to an elbow dislocation is still a subject of debate. As the force from a fall is transmitted to the extended
* Corresponding author. E-mail address: lfi[email protected] (L.D. Field).
Intrinsic stability of the elbow is provided by both osseous and ligamentous structures. The ulnohumeral articulation is the cornerstone of osseous stability and mobility in the flexion– extension plane. The coronoid process resists posterior subluxation in flexion. The medial facet of the coronoid imparts an osseous stability to varus stress. The radial head also provides elbow stability as a secondary stabilizer to valgus loads [7]. Most activities in athletes rely on a combination of ligamentous integrity and bony articulation to provide stability to the elbow. The medial ulnar collateral ligament (MUCL) is compromised of three major bundlesdanterior, posterior and transverse bands (Fig. 3). The anterior band provides the primary restraint to valgus stress at 30 , 60 , and 90 of flexion (Fig. 4) [8]. It originates from the anterior inferior aspect of the
0749-0712/08/$ - see front matter Ó 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.hcl.2007.11.012
hand.theclinics.com
2
HOBGOOD
et al
Fig. 1. (A) Anterior-posterior and (B) lateral radiographs demonstrating a posterolateral elbow dislocation. This pattern is by far the most common dislocation pattern.
medial epicondlyle and inserts onto the sublime tubercle of the coronoid. The posterior bundle is fan-shaped and also originates from the medial epicondyle. It inserts onto the medial margin of the semilunar notch. The lateral ligament complex consists of four components: the LCL, the LUCL (ulnar part of
Fig. 2. The ring of instability with elbow dislocations describes the progression of stresses from the lateral ulnar part of the lateral collateral ligament to the anterior capsule and finally ending with injury to the medial ulnar collateral ligament. (From O’Driscoll SW, Jupiter JB, King GJW, et al. The unstable elbow. Instr Course Lect 2001;50:89–102; with permission.)
LCL), the accessory LCL, and the annular ligament (Fig. 5). The LCL attaches to the lateral epicondyle and fans out to merge indistinguishably with the annular ligament. It functions as a varus restraint and stabilizes the annular ligament. The lateral capsule of the elbow consists of three layers: the joint capsule, annular ligament, and lateral ligament. The joint capsule is the deep layer, and the true annular ligament is the intermediate layer. The superficial layer consists of the lateral ligament, which fans out from the lateral epicondyle to attach to the anterior and
Fig. 3. The ulnar collateral ligament is comprised of three bandsdanterior, posterior, and transverse bands. (From Morrey BF, Tanaka S, An KN. Valgus stability of the elbow. A definition of primary and secondary constraints. Clin Orthop 1991;265:187–95; with permission.)
ACUTE DISLOCATIONS OF THE ADULT ELBOW
3
Fig. 4. The anterior band of the lateral collateral ligament is the primary restraint to the valgus stress at 30 to 90 degrees of flexion. It originates from the anterior inferior aspect of the medial epicondyle and inserts on the sublime tubercle. It is approximately 5 mm wide and 27 mm long. (From Morrey BF, Tanaka S, An KN. Valgus stability of the elbow. A definition of primary and secondary constraints. Clin Orthop 1991;265:187–95; with permission.)
posterior aspects of the proximal ulna [9]. The LUCL is a thickening of the capsule that attaches proximally to the lateral humeral epicondyle and distally to the tubercle of the supinator crest of the ulna [10]. The humeral attachment of the LUCL is at the isometric point on the lateral side of the elbow. The distal attachment of the ligament is deep to the fascia surrounding the
extensor carpi ulnaris and supinator muscles. Besides stabilizing the lateral aspect of the elbow, the LUCL also acts as a posterior buttress for the radial head to prevent its subluxation. Josefsson and colleagues demonstrated that all 15 patients who underwent surgical exploration after acute complete elbow dislocation demonstrated injury to both the medial and lateral ligamentous complex [11].
Classification
Fig. 5. The lateral ligamentous complex of the elbow. (From Mehta J, Bain G. Posterolateral rotatory instability of the elbow. J Am Acad Orthop Surg 2004;12,6: 405–15; and adapted from Bain GI, Mehta JA. Anatomy of the elbow joint and surgical approaches. In: Baker CI, Plancher KD, editors. Operative treatment of elbow injuries. New York: Springer-Verlag; 2001; with permission.)
Multiple classification systems have been proposed for elbow dislocations. Chronologically, elbow dislocations can be described as acute, chronic (unreduced), and recurrent. The temporal definition of chronic elbow dislocation is not defined clearly, but if a joint remains unreduced for more than 7 days, the utility of closed reduction is minimal. Anterior dislocations of the elbow without associated fractures are exceedingly uncommon. Medial and lateral dislocations are likely to be incompletely reduced posterior dislocations. Consequently, classification of simple elbow dislocations into anterior, medial, lateral, and posterior is not very useful. O’Driscoll and colleagues [6] have proposed a classification system with clinical relevance (Fig. 6). This describes a spectrum of instability, from subluxation to
4
HOBGOOD
et al
Fig. 6. The spectrum of elbow instability, from subluxation to dislocation. States 1–3 correspond with the stages of capsuloligamentous disruption as discussed earlier. (From O’Driscoll SW, Jupiter JB, King GJW, et al. The unstable elbow. Instr Course Lect 2001;50:89–102; with permission.)
dislocation. The three stages correspond with the pathoanatomical stages of the capsuloligamentous disruption. A perched dislocation is one in which the elbow is subluxed but the coronoid is impinged upon the trochlea. Evaluation It is of paramount importance that the neurovascular status of the dislocated elbow be assessed and documented before manipulation. Specifically, the status of the brachial artery and median and ulnar nerves should be determined as they are most vulnerable to entrapment during manipulation. Serial neurovascular examinations should be considered in cases in which massive antecubital fossa swelling exists or in which the patient is believed to be at risk for a compartment syndrome. If clinical signs are indicative of a compartment syndrome, emergent fasciotomies of the forearm and hand should be performed. Angiography or magnetic resonance-arthrogram may be necessary to evaluate for vascular compromise. Radiographic evaluation should include standard anteroposterior and lateral radiographs and should be obtained to determine the dislocation pattern and scrutinized for associated fractures about the elbow. If there is any concern of pending vascular compromise or compartment
syndrome, the patient should be admitted for observation. Treatment options Closed reduction for simple dislocation In a perched dislocation, an analgesic with intra-articular local anesthetic is often adequate to perform a reduction maneuver. Direct pressure is applied over the olecranon while the elbow is extended slightly and gentle axial distraction is performed. For complete elbow dislocations, closed reduction should be performed under conscious sedation in a monitored emergency department setting. This will allow for relaxation of muscle spasm such that with slow, continuous, gentle, longitudinal traction combined with gradual flexion with an anterior directed force over the olecranon, the elbow should reduce without difficulty. Some authors report hyperextension of the deformity first to unlock the olecranon, but the potential danger remains of median nerve entrapment. Repeated attempts at reduction should be avoided, as soft tissue injury and swelling can worsen. After obtaining a reduction, the elbow should be taken through a range of motion to evaluate the arc of stability. Simple dislocations usually are stable throughout a full range of motion;
ACUTE DISLOCATIONS OF THE ADULT ELBOW
however, subluxation or dislocation in extension must be ruled out. If the elbow subluxates or dislocates in extension, the forearm should be pronated fully and the stability reassessed. If forearm pronation eliminates instability in extension, a hinged brace should be applied with the forearm in full pronation. Residual instability in full extension or near full extension will necessitate an extension block. However, if an extension block of more than 30 to 45 is required, surgical repair should be considered [12]. Neurovascular status is evaluated after reduction. Postreduction radiographs should be obtained to confirm a congruent reduction. Open reduction The need for open reduction after simple, acute dislocation is uncommon. Operative intervention is required when closed reduction proves unsuccessful or is otherwise contraindicated. Radial head entrapment can occur as the head becomes entrapped in the soft tissues of the forearm or even buttonholed through the forearm fascia. Medial epicondyle fractures also can become incarcerated within the joint and prevent closed reduction. The surgical approach of arthrotomy and removal of incarcerated tissue should be tailored to the specific injury pattern. For example, radial head entrapment causing a locked elbow dislocation should be approached through a lateral Kocher approach.
5
Surgical treatment As previously stated, surgical repair should be considered if the elbow requires more than 45 of flexion to remain congruent. This is seen uncommonly in simple elbow dislocations, but it can result with high energy trauma. In this situation, the full spectrum of ligamentous and capsular disruption has occurred from lateral to medial, stripping the entire distal humerus of soft tissue. A universal posterior skin incision is used, allowing access to both the medial and lateral sides of the elbow. The avulsed lateral collateral ligament and common extensor origin are reattached to the lateral epicondyle using suture anchors. Care is taken to ensure that the repair is performed through the point of isometry of the lateral ulnar collateral ligament. Stability in extension then is evaluated. If the elbow continues to dislocate in extension, the anterior and medial soft tissue injuries must be repaired. A medial subcutaneous flap is elevated, and the ulnar nerve is transposed. The anterior capsule then is secured to the coronoid with sutures passed through drill holes into the coronoid entering from the dorsal surface of the ulna. The medial collateral ligament and common flexor origins then are repaired to the medial epicondyle using suture anchors. Stability in extension then is reassessed. If the elbow continues to dislocate, a hinged external fixator is applied (Fig. 7). Application of the hinged
Fig. 7. (A, B) The hinged external fixator is a useful adjunct in the setting of gross instability. Again, this is seen with high-energy mechanisms; often, major soft tissue trauma as well as fracture dislocations are seen. (Image provided courtesy of Stryker Orthopaedics, Mahwah, NJ; with permission.)
6
HOBGOOD
external fixator will allow full unrestricted motion while maintaining a congruent reduction. Usually, the lateral soft tissue repair is sufficient to restore stability, especially in older patients. High-energy injuries in the young patient, however, can require repair of the anterior capsule, medial collateral ligament, and common flexor origin in addition to the lateral repair. Weighing the evidence Closed treatment of simple elbow dislocations in adults has demonstrated satisfactory results. Van der Ley [13] showed 80% good or excellent results in 20 adults who had simple elbow dislocations treated by closed methods. There was no long-term instability with a minimum of 5 years follow up. Some authors have advocated acute surgical repair of the medial ulnar collateral ligament and/ or the lateral collateral ligament complex following simple elbow dislocations [14]. Josefsson and colleagues [11], however, showed that no benefit was gained from acute ligamentous repair of simple dislocations when compared with closed methods. Surgical repair of medial or lateral ligament disruption rarely is indicated in the treatment of uncomplicated elbow dislocations. In the unlikely setting of persistent instability with more than 30 to 45 of flexion, however, soft tissue disruption has occurred to a degree that will require ligamentous repair as described previously. The use of the hinged elbow external fixator for uncomplicated elbow dislocations has not been evaluated critically in the literature. There are multiple studies to validate its use in the setting of complex elbow fracture dislocation, however [15,16]. The fixator does provide for a concentric reduction to be maintained while range of motion exercises are begun. The soft tissue repairs also are protected from early varus or valgus stress. Mobilization recommendations For simple elbow dislocations, the elbow is immobilized for a maximum of 5 to 7 days in slightly less than 90 of flexion depending on the degree of anterior soft tissue swelling in a posterior splint. If the elbow was stable on the postreduction examination, full unprotected motion should be started no later than 1 week after injury. If forearm pronation was required to prevent extension instability, full range of motion is
et al
allowed in a hinged brace with the forearm fully pronated. The patient may only come out of the brace for motion exercises in full pronation under the guidance of a skilled therapist. The brace is worn for 4 weeks. If an extension block was required, the block should be reduced gradually so that by 4 weeks the brace allows full motion. The brace is discontinued at 4 weeks. If surgical repair is required, the elbow is changed from a posterior splint to an unlocked, hinged brace at 1 week after surgery. The patient only is allowed out of the brace for motion exercises under the guidance of a skilled therapist. The brace is discontinued at 4 weeks. If a hinged external fixator is required, it is removed 4 to 6 weeks postoperatively.
Summary The intrinsic stability provided by the bony articulations of the elbow make recurrent instability an uncommon problem after simple dislocations. These injuries usually can be managed by closed reduction and early motion. Special attention to stability immediately after reduction is necessary to guide treatment. Protected motion in full pronation and/or with a block to full extension may be required. Although uncommonly necessary, the surgeon must be prepared for open surgical repair of soft tissue injury to restore stability.
Further readings Bucholz R, editor. Rockwood and Green’s fractures in adults. 5th edition. New York: Lippincott Williams and Wilkins; 2002. p. 921–34. Josefsson PO, Johnell O, Gentz CF. ‘‘Long-term sequelae of simple dislocations of the elbow.’’ J Bone Joint Surg Br 1984;66-A:927–30. Josefsson PO, Gentz CF, Johnell O. Surgical versus nonsurgical treatment of ligamentous injuris following dislocation of the elbow joint. J Bone Joint Surg Br 1987;69-A:605–8. Mehta J, Bain G. Posterolateral rotatory instability of the elbow. J Am Acad Orthop Surg 2004;12:405–15. Morrey BF, An KN. Articular and ligamentous contributions to the stability of the elbow joint. Am J Sports Med 1983;11:315–9. O’Driscoll SW, Morrey BF. Elbow dislocation and subluxation: a spectrum on instability. Clin Orthop 1992;280:186–97. O’Driscoll S, Jupiter J, King Graham, et al. ‘‘The Unstable Elbow.’’ J Bone Joint Surg Br;82-A(5):724–38.
ACUTE DISLOCATIONS OF THE ADULT ELBOW
References [1] Josefsson PO, Johnell O, Wendeberg B. Ligamentous injuries in dislocations of the elbow joint. Clin Orthop 1987;221:221–5. [2] Josefsson PO, Nilsson BE. Incidence of elbow dislocation. Acta Orthop Scand 1986;47:537–8. [3] Kenter K, Behr CT, Warren RF, et al. Acute elbow injuries in the national football league. J Shoulder Elbow Surg 2000;9:1–5. [4] Ring D. Fractures and dislocations of the elbow. In: Rockwood CA Jr, Green DP, Bucholz RW, et al, editors. Fractures in adults. 6th edition. Philadelphia: Lippincott Williams & Wilkins; 2006. p. 989–1049. [5] Mehlhoff TL, Noble PC, Bennett JB, et al. Simple dislocation of the elbow in adults. J Bone Joint Surg Am 1988;70:244–9. [6] O’Driscoll SW, Morrey BF, An KN. Elbow dislocation and subluxation: a spectrum of instability. Clin Orthop 1992;280:186–97. [7] Morrey BF, An KN. Articular and ligamentous contribution to the stability of the elbow in the adult. Am J Sports Med 1983;11:315–9. [8] Morrey BF, Tanaka S, An KN. Valgus stability of the elbow. A definition of primary and secondary constraints. Clin Orthop 1991;265:187–95.
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[9] Martin BF. The annular ligament of the superior radio-ulnar joint. J Anat 1958;92:473–82. [10] Morrey BF, An KN. Functional anatomy of the ligaments of the elbow. Clin Orthop Relat Res 1985;201:84–90. [11] Josefsson PO, Gentz CF, Johnell O. Surgical versus nonsurgical treatment of ligamentous injuries following dislocation of the elbow joint: a prospective randomized study. J Bone Joint Surg Am 1987;69: 605–8. [12] O’Driscoll SW, Jupiter JB, King GJW, et al. The unstable elbow. Inst Course Lect 2001;50:89–102. [13] Van der Ley J. Conservative treatment of elbow dislocations in adults. Neth J Surg 1987;39(6): 167–9. [14] Durig M, Muller W, Reudi TP. The operative treatment of elbow dislocations in the adult. J Bone Joint Surg Am 1979;61:239–44. [15] Mckee MD, Bowden SH, King GJ, et al. Management of recurrent, complex instability of the elbow with a hinged external fixator. J Bone Joint Surg Br 1998;80(6):1031–6. [16] Yu JR, Throckmorton TW, Bauer RM, et al. Management of acute complex instability of the elbow with hinged external fixation. J Shoulder Elbow Surg 2007;16:60–7.