SUMMARY

• Elbow Dislocations are common elbow injuries which can be characterized as simple or complex depending on associated injury to nearby structures. 

• Diagnosis can be made with plain radiographs. CT studies can be helpful to evaluate for loose bodies or for surgical planning.

• Treatment is closed reduction followed by a short period of immobilization for stable simple elbow dislocations. Surgical management is indicated for complex elbow dislocations associated with fractures or persistent instability.

EPIDEMIOLOGY

• Incidence

  • elbow dislocations are the most common major joint dislocation second to the shoulder

    • most common dislocated joint in children

  • account for 10-25% of injuries to the elbow

  • posterolateral is the most common type of dislocation (80%)

• Demographics

  • predominantly affects patients between age 10-20 years old

ETIOLOGY

• Pathophysiology

  • mechanism for posterolateral dislocation

    • usually a combination of

      • axial loading

      • supination/external rotation of the forearm

      • valgus posterolateral force

    • a varus posteromedial mechanism (combined with axial load and forearm external rotation) has also been reported

    • posterior dislocations may involve more than one injury mechanism

  • pathoanatomy

    • associated with complete or near complete circular disruption of capsuloligamentous stabilizers

    • pathoanatomic cascade

      • progression of injury is from lateral to medial

        • LCL fails first (primary lesion)

          • by avulsion of the lateral epicondylar origin

          • midsubstance LCL tears are less common but do occur 

             

        • MCL fails last depending on degree of energy

• Associated injuries

  • shoulder and wrist injuries

    • concomitant shoulder and wrist injuries occur in 10-15% of elbow dislocations

ANATOMY

• Osteology

  • static and dynamic stabilizers confer stability to the elbow 

    • static stabilizers (primary)

      • ulnohumeral joint

      • anterior bundle of the MCL

      • LCL complex (includes the LUCL) 

         

    • static stabilizers (secondary)

      • radiocapitellar joint

      • joint capsule

      • origins of the common flexor and extensor tendons

    • dynamic stabilizers

      • muscles that cross the elbow joint, which apply compressive (stabilizing) force

        • anconeus

        • brachialis

        • triceps

• See complete Anatomy and Biomechanics of Elbow 

CLASSIFICATION

• Anatomic 

  • based on anatomic location of olecranon relative to humerus

    • posterolateral

      • most common

• Simple vs. complex

  • simple 

    • elbow dislocation with no associated fracture

    • accounts for 50-60% of elbow dislocations

  • complex 

    • elbow dislocation with associated fracture

    • may take form of

      • terrible triad injury 

        • elbow dislocation associated with a LUCL tear, radial head fracture, and coronoid tip fracture

          • radial head fractures occur in up to 10% of elbow dislocations

      • varus posteromedial rotatory instability 

         

        • elbow injury associated with an LCL tear and a coronoid fracture

        • radial head fracture unlikely  

           

        • coronoid fracture characterisitics

          • medial facet fracture

          • comminuted

PRESENTATION

• Symptoms

  • pain and swelling

• Physical exam

  • inspection

    • the status of the skin - evaluate for open injuries

  • palpation

    • presence of compartment syndrome

    • status of wrist and shoulder

      • concomitant injuries occur in 10-15% of elbow dislocations

  • neurovascular status

IMAGING

• Radiographs

  • recommended views

    • AP and lateral views

      • assess joint congruency, especially after attempted reduction

    • oblique views

      • assess for associated periarticular fractures

• CT scan

  • indications

    • suspicion of complex injury pattern

    • useful to identify associated periarticular fractures

TREATMENT

• Nonoperative

  • closed reduction and immobilization with early motion  

     

    • indications

      • acute simple stable dislocations

      • recurrent instability after simple dislocations is rare (<1-2% of dislocations)

  • techniques

    • splint in at least 90° of flexion for 5-10 days

    • begin early supervised physical therapy

• Operative

  • open reduction internal fixation (ORIF) with ligament repair

    • indications

      • closed reduction cannot be performed

        • often due to entrapped soft tissue or osteochondral fragments

      • persistent instability after reduction 

         

      • acute complex elbow dislocations

        • presence of coronoid, radial head, olecranon fractures

    • technique

      • ORIF of coronoid, radial head, olecranon fracture if present

      • ligament repair

        • perform LCL repair +/- MCL repair depending on intraoperative stability

      • postoperative

        • elbow requires >50-60° to maintain reduction

  • open reduction, capsular release, and dynamic hinged elbow fixator

    • indications

      • chronic dislocations

    • postoperative

      • hinged external fixator indicated in chronic dislocation to protect the reconstruction and allow early range of motion

TECHNIQUE

• Closed reduction and immobilization with early motion 

  • closed reduction

    • technique

      • ensure patient has sufficient analgesia to allow for adequate muscle relaxation

      • reduction maneuver requires a combination of:

        • inline traction to improve coronal displacement

        • forearm supination to shift the coronoid under the trochlea

        • elbow flexion while placing direct pressure on tip of olecranon

      • a palpable "clunk" can be appreciated after most reductions

      • assess post reduction stability

        • elbow is often unstable in extension

        • elbow is often unstable to valgus stress

          • test by stressing elbow with forearm in pronation to lock the lateral side

  • immobilization

    • place post-reduction posterior mold splint in flexion and appropriate forearm rotation

      • splint in at least 90° of elbow flexion

      • if LCL is disrupted - elbow will be more stable in pronation 

         

      • if MCL is disrupted - elbow will be more stable in supination

  • post-reduction radiographs

    • obtain following reduction in immobilization

      • if joint is concentric, immobilize (5-10 days) and start early therapy

      • obtain repeat radiographs at 3-5 days and 10-14 days to confirm reduction

  • rehabilitation

    • initial

      • immobilize for 5-10 days

      • immobilization for >3 weeks results in poor final ROM outcomes

    • early

      • supervised (therapist) active and active assist range-of-motion exercises within stable arc

      • extension block brace is used for 3-4 weeks

      • proceed with light duty use 2 weeks from injury 

         

    • late rehabilitation

      • extension block is decreased such that by 6-8 weeks after the injury full stable extension is achieved

• Open reduction internal fixation (ORIF) with ligament repair

  • approach

    • approach depends on the location of the pathology

      • Kocher approach (ECU/anconeus)

        • used to address the LCL complex, common extensor tendon origin, coronoid, capitellum, and/or radial head fractures

        • when approaching joint (ie, for radial head fractures) during deep dissection, make incision slightly anterior to midline of the radial head to protect the posterior fibers of the LCL complex

        • take care with retractor placement to avoid injury to the PIN

      • medial approach

        • used to address the MCL, flexor/pronator mass origin, and/or comminuted coronoid fractures

        • identify and protect the ulnar nerve

    • posterior approach

  • internal fixation with ligament repair

    • coronoid fractures

      • ORIF

        • rarely needed, as most fractures involve only the coronoid tip (proximal to insertion of brachialis)

        • typically approached laterally, but can also be addressed via a medial approach, especially if comminuted

    • radial head fractures

      • ORIF

        • when placing fixation on the proximal radius, one must be aware of the "safe zone" (a 90° arc in the radial head that does not articulate with the proximal ulna) 

           

          • the "safe zone" can be identified by its relationship to Lister's tubercle and the radial styloid

      • radial head arthroplasty

        • indicated if radial head can not be reconstructed

        • if radial head is replaced the replacement should be anatomic and restore normal length/size

          • this improves the varus and external rotatory stability of the elbow, but stability isn't restored until LCL is addressed

          • excision of the radial head leads to varus/external rotatory instability when the LCL function is absent

    • LCL

      • repaired or reconstructed

      • extensor origin avulsion is common and may be repaired

    • MCL

      • if instability persists following LCL repair, the MCL is repaired or reconstructed

  • postoperative

    • elbow requires >50-60° to maintain reduction

    • depending on stability of the elbow, active ROM exercises may commence while using a brace

    • an extension block may or may not be used

• Hinged external fixator

  • only necessary if elbow remains unstable after attempt at fixation as described above

COMPLICATIONS

• Early stiffness 

   

  • loss of terminal extension is the most common complication after closed treatment of a simple elbow dislocation 

  • early, active ROM can help prevent this from occurring

  • static, progressive splinting can be helpful after inflammation has decreased

    • often between 6-8 weeks after surgery

• Varus posteromedial instability

  • injury to the LCL and fracture of the anteromedial facet of the coronoid 

     

  • solid fixation of the anteromedial facet is critical for functional outcome and prevention of arthrosis

• Neurovascular injuries

  • brachial artery injuries (rare) typically associated with open dislocations

  • ulnar nerve injury typically results from stretch

  • median nerve injury (rate) typcially associated with brachial artery injury

• Compartment syndrome

• Damage to articular surface

• Recurrent instability

• Heterotopic ossification

  • may require excision to improve elbow range of motion 

     

• Contracture/stiffness

  • correlated with immobilization beyond 3 weeks