Traumatic Elbow Instability


  • Neurovascular exam pre and post reduction
  • X-ray assessment
  • Reduction: correct medial or lateral displacement first, f/b pressure to posterior olecranon to bring anterior over trochlea
  • Muscle relaxation is key
  • Palpable / audible "clunk" good sign re: stability
  • Assess post-reduction x-rays, ipsilateral UE for associated injuries: 10-15%
  • Don’t forget DRUJ, Int. Mem.  
  • Range Elbow Joint
  • Assess valgus stability with forearm pronated (to lock the lateral side)
  • Assess potential for redislocation in extension: signifies unstable elbow
  • Post-Reduction x-rays:
  • AP and lateral
  • Check for congruency
  • Incongruent reduction: widening, osteochondral fragments, rotary instability





    Primary Stabilizers

     Primary Static Stabilizers

    1.Ulnohumeral Joint


    3.LCL, esp. LUCL


    Secondary Stabilizers


      Secondary Stabilizers

    1.Radial Head


    3.Flexor / pronator and extensor masses


    Dynamic Stabilizers

      Dynamic Stabilizers

    Muscles that cross the elbow and provide joint compressive forces
  • Anconeus
  • Triceps
  • Brachialis


    Descriptive Classification


    Posterolateral: >90%





    Divergent: rare


    Mechanism of Injury

      Posterior Dislocation

  • Elbow extension
  • Valgus force
  • Forearm supination

Anterior Dislocation

Elbow flexed

Direct force to posterior forearm



  Mechanism usually involves posterolateral pattern

Progression of Injury: lateral to medial


Stage 1: LCL, usually ulnar portion

Leads to posterolateral rotary subluxation

Rotary instability


Stage 2: anterior and posterior disruption

Leads to posterolateral dislocation as coronoid is perched on trochlea

Varus instability

Stage 3A: all soft tissue stabilizers except ant. MCL disrupted

Intact ant. MCL provides some stability if forearm pronated

Commonly seen along with radial head & coronoid fx

Stage 3B: entire MCL disrupted

Rotary, Varus, Valgus  instability

Stage 3C: entire distal humerus stripped of soft tissue

Instability despite LAC @ 90°  



  Simple Dislocation

Dislocation of ulnohumeral joint without associated fracture


Complex Dislocation

Dislocation of ulnohumeral joint with associated fracture about the elbow


Terrible Triad

Elbow dislocation, radial head and coronoid fracture   


Simple Dislocation: Treatment +§+Recurrent Instability: 1-2%

Concentric stable reduction: post. splint  @ 90° w/ struts

Repeat radiographs @ 3-5, 10-14 days confirming reduction

Immobilize <3 weeks

Start gentle AROM

Increase extension over next 3 weeks

Vigorous PROM associated with H.O.

Patient apprehension with terminal extension: orthosis with block


Josefsson PO et al CORR 1987;221:221-225

Prospective Study of Simple, Closed Elbow Dislocations

31 simple elbow dislocations taken to OR for EUA, open exploration

9 redislocated easily with EUA; tendency to redislocate was associated with degree of flexor / pronator and extensor mass disruption

Complete disruption of medial and lateral collateral ligaments found in every case, usually at the humeral insertion.


Mehlhoff TL et al JBJS 1988;70: 244-249

52 simple elbow dislocations treated closed, average follow-up >34 months

Duration of immobilization before motion varied

No excellent outcomes in elbows immobilized >2 weeks

Immobilization for 4 weeks yielded all fair or poor results

No fair or poor results in elbows immobilized <18 days

"The results indicate that early active motion is the key factor in rehabilitation of the elbow after dislocation."


Complex Dislocation +§+Elbow Dislocation with Associated Elbow Fracture:

Radial head (5-11%)

Coronoid (5-10%)

Medial or Lateral Epicondyle (12-34%) 

Classic Study discussing treatment of radial head fractures associated w/ elbow dislocation

Broberg MA and Morrey BF CORR 1987 216: 109-119

24 patients with type IV radial head fracture, 2-35 yr. follow up

Treatment: 10 closed, 14 open

6/10 closed required further treatment

14 open: 5 partial, 5 complete radial head excision, 3 Silastic implants, 1 ORIF

Conclusion: prognosis better than anticipated

3 excellent / 15 good / 6 fair

Best results: Mason II treated closed, Mason III complete excision

Early treatment: reduce elbow, treat fracture accordingly

Immobilization >4 weeks should be avoided  

Contemporary Study discussing treatment of radial head fractures associated w/ elbow dislocations

Doornberg JN et al JBJS 2007;89:1075-80

27 consecutive complex elbow dislocations: 11 type II, 16 type III (13 terrible triad injuries) radial head fractures

Treated with "loose" fitting modular radial head prosthesis

13 excellent / 9 good / 3 fair / 2 poor according to Mayo Elbow Performance Index

Stability restored in all 27 elbows

68% demonstrated radiographic evidence of lucency around stem

7 reoperations / 9 capitellar arthrosis / 13 heterotopic ossification

Points / prosthesis indications: Mason III with >3 articular fragments, lost or irreparable fragments

Type IV radial head fractures consistently involve >30% radial head

Fractures typically involve most important area of radial head: anterolateral portion; buttress against posterior dislocation

Fractures often comminuted with wide displacment, fragments often lost or irreparable


Cohen and Hastings JAAOS 1998 §Operative Indications:

1.Elbow requires flexion >50-60% to remain reduced

2.Unstable fractures about the elbow joint 

Terrible Triad +1.+Elbow Dislocation

2.Radial Head Fracture

3.Coronoid fracture

Fracture fragment usually transverse and small (average 40% coronoid height)


Surgical Protocol for Terrible Triad §McKee MD et al JBJS March 2005 87-A

36 consecutive terrible triad injuries

Surgical Protocol: ORIF coronoid, ORIF or replace radial head, repair lateral structures, repair MCL or hinged ex-fix

15 excellent / 13 good / 7 fair / 1 poor

Concentric stability: 34

8 reoperations: 1 recurrent instability, 2 synostosis


Associated Injuries and Complications§Brachial Artery Disruption

<30 cases reported in the literature with closed injuries


Prompt surgical intervention: anteromedial approach and interpositional vein graft

§schemia >4 hr: fasciotomy


Neurologic Injury: Uncommon (up to 20%)

Ulnar (most often) : neuropraxia

Median / AIN: may occur with concomitant vascular disruption due to proximity  


Heterotopic Ossification

Soft tissue calcification (75%)

Anterior elbow and collaterals

Rarely limits motion

True Ectopic Calcification (5%)

Evident by 3-4 weeks

Brachialis region

Causes: delayed intervention, closed head injury, aggressive PROM

Resection: delayed until ossification appears mature; ~ 6 months after injury


DRUJ Injury

Essex Lopresti variant

Combined injury makes fixation of radial head more important

Valgus stability

Axial stability

May pin DRUJ in neutral