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SUMMARY
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Elbow Dislocations are common elbow injuries which can be characterized as simple or complex depending on associated injury to nearby structures.
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Diagnosis can be made with plain radiographs. CT studies can be helpful to evaluate for loose bodies or for surgical planning.
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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.
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EPIDEMIOLOGY
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Incidence
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elbow dislocations are the most common major joint dislocation second to the shoulder
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most common dislocated joint in children
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account for 10-25% of injuries to the elbow
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posterolateral is the most common type of dislocation (80%)
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Demographics
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predominantly affects patients between age 10-20 years old
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ETIOLOGY
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Pathophysiology
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mechanism for posterolateral dislocation
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usually a combination of
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axial loading
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supination/external rotation of the forearm
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valgus posterolateral force
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a varus posteromedial mechanism (combined with axial load and forearm external rotation) has also been reported
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posterior dislocations may involve more than one injury mechanism
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pathoanatomy
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associated with complete or near complete circular disruption of capsuloligamentous stabilizers
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pathoanatomic cascade
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progression of injury is from lateral to medial
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LCL fails first (primary lesion)
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by avulsion of the lateral epicondylar origin
- midsubstance LCL tears are less common but do occur
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MCL fails last depending on degree of energy
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Associated injuries
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shoulder and wrist injuries
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concomitant shoulder and wrist injuries occur in 10-15% of elbow dislocations
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ANATOMY
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Osteology
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static and dynamic stabilizers confer stability to the elbow
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static stabilizers (primary)
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ulnohumeral joint
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anterior bundle of the MCL
- LCL complex (includes the LUCL)
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static stabilizers (secondary)
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radiocapitellar joint
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joint capsule
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origins of the common flexor and extensor tendons
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dynamic stabilizers
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muscles that cross the elbow joint, which apply compressive (stabilizing) force
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anconeus
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brachialis
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triceps
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See complete Anatomy and Biomechanics of Elbow
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CLASSIFICATION
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Anatomic
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based on anatomic location of olecranon relative to humerus
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posterolateral
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most common
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Simple vs. complex
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simple
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elbow dislocation with no associated fracture
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accounts for 50-60% of elbow dislocations
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complex
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elbow dislocation with associated fracture
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may take form of
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terrible triad injury
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elbow dislocation associated with a LUCL tear, radial head fracture, and coronoid tip fracture
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radial head fractures occur in up to 10% of elbow dislocations
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- varus posteromedial rotatory instability
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elbow injury associated with an LCL tear and a coronoid fracture
- radial head fracture unlikely
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coronoid fracture characterisitics
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medial facet fracture
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comminuted
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PRESENTATION
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Symptoms
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pain and swelling
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Physical exam
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inspection
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the status of the skin - evaluate for open injuries
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palpation
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presence of compartment syndrome
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status of wrist and shoulder
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concomitant injuries occur in 10-15% of elbow dislocations
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neurovascular status
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IMAGING
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Radiographs
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recommended views
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AP and lateral views
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assess joint congruency, especially after attempted reduction
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oblique views
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assess for associated periarticular fractures
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CT scan
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indications
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suspicion of complex injury pattern
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useful to identify associated periarticular fractures
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TREATMENT
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Nonoperative
- closed reduction and immobilization with early motion
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indications
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acute simple stable dislocations
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recurrent instability after simple dislocations is rare (<1-2% of dislocations)
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techniques
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splint in at least 90° of flexion for 5-10 days
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begin early supervised physical therapy
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- closed reduction and immobilization with early motion
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Operative
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open reduction internal fixation (ORIF) with ligament repair
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indications
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closed reduction cannot be performed
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often due to entrapped soft tissue or osteochondral fragments
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- persistent instability after reduction
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acute complex elbow dislocations
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presence of coronoid, radial head, olecranon fractures
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technique
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ORIF of coronoid, radial head, olecranon fracture if present
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ligament repair
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perform LCL repair +/- MCL repair depending on intraoperative stability
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postoperative
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elbow requires >50-60° to maintain reduction
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open reduction, capsular release, and dynamic hinged elbow fixator
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indications
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chronic dislocations
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postoperative
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hinged external fixator indicated in chronic dislocation to protect the reconstruction and allow early range of motion
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TECHNIQUE
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Closed reduction and immobilization with early motion
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closed reduction
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technique
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ensure patient has sufficient analgesia to allow for adequate muscle relaxation
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reduction maneuver requires a combination of:
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inline traction to improve coronal displacement
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forearm supination to shift the coronoid under the trochlea
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elbow flexion while placing direct pressure on tip of olecranon
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a palpable "clunk" can be appreciated after most reductions
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assess post reduction stability
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elbow is often unstable in extension
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elbow is often unstable to valgus stress
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test by stressing elbow with forearm in pronation to lock the lateral side
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immobilization
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place post-reduction posterior mold splint in flexion and appropriate forearm rotation
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splint in at least 90° of elbow flexion
- if LCL is disrupted - elbow will be more stable in pronation
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if MCL is disrupted - elbow will be more stable in supination
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post-reduction radiographs
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obtain following reduction in immobilization
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if joint is concentric, immobilize (5-10 days) and start early therapy
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obtain repeat radiographs at 3-5 days and 10-14 days to confirm reduction
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rehabilitation
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initial
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immobilize for 5-10 days
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immobilization for >3 weeks results in poor final ROM outcomes
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early
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supervised (therapist) active and active assist range-of-motion exercises within stable arc
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extension block brace is used for 3-4 weeks
- proceed with light duty use 2 weeks from injury
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late rehabilitation
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extension block is decreased such that by 6-8 weeks after the injury full stable extension is achieved
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Open reduction internal fixation (ORIF) with ligament repair
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approach
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approach depends on the location of the pathology
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Kocher approach (ECU/anconeus)
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used to address the LCL complex, common extensor tendon origin, coronoid, capitellum, and/or radial head fractures
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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
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take care with retractor placement to avoid injury to the PIN
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medial approach
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used to address the MCL, flexor/pronator mass origin, and/or comminuted coronoid fractures
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identify and protect the ulnar nerve
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posterior approach
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internal fixation with ligament repair
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coronoid fractures
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ORIF
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rarely needed, as most fractures involve only the coronoid tip (proximal to insertion of brachialis)
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typically approached laterally, but can also be addressed via a medial approach, especially if comminuted
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radial head fractures
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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)
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the "safe zone" can be identified by its relationship to Lister's tubercle and the radial styloid
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- 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)
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radial head arthroplasty
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indicated if radial head can not be reconstructed
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if radial head is replaced the replacement should be anatomic and restore normal length/size
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this improves the varus and external rotatory stability of the elbow, but stability isn't restored until LCL is addressed
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excision of the radial head leads to varus/external rotatory instability when the LCL function is absent
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LCL
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repaired or reconstructed
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extensor origin avulsion is common and may be repaired
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MCL
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if instability persists following LCL repair, the MCL is repaired or reconstructed
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postoperative
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elbow requires >50-60° to maintain reduction
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depending on stability of the elbow, active ROM exercises may commence while using a brace
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an extension block may or may not be used
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Hinged external fixator
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only necessary if elbow remains unstable after attempt at fixation as described above
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COMPLICATIONS
- Early stiffness
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loss of terminal extension is the most common complication after closed treatment of a simple elbow dislocation
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early, active ROM can help prevent this from occurring
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static, progressive splinting can be helpful after inflammation has decreased
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often between 6-8 weeks after surgery
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Varus posteromedial instability
- injury to the LCL and fracture of the anteromedial facet of the coronoid
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solid fixation of the anteromedial facet is critical for functional outcome and prevention of arthrosis
- injury to the LCL and fracture of the anteromedial facet of the coronoid
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Neurovascular injuries
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brachial artery injuries (rare) typically associated with open dislocations
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ulnar nerve injury typically results from stretch
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median nerve injury (rate) typcially associated with brachial artery injury
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Compartment syndrome
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Damage to articular surface
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Recurrent instability
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Heterotopic ossification
- may require excision to improve elbow range of motion
- may require excision to improve elbow range of motion
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Contracture/stiffness
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correlated with immobilization beyond 3 weeks
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- Early stiffness