Traumatic Elbow Instability

Evaluation

  • 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


     


     


    Anatomy


     


    Primary Stabilizers


     Primary Static Stabilizers


    1.Ulnohumeral Joint


    2.MCL


    3.LCL, esp. LUCL


     


    Secondary Stabilizers


     


      Secondary Stabilizers


    1.Radial Head


    2.Capsule


    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


      Posterior


    Posterolateral: >90%


    Posteromedial


    Anterior


    Lateral


    Medial


    Divergent: rare


     


    Mechanism of Injury


      Posterior Dislocation


    F.O.O.S.H.
  • Elbow extension
  • Valgus force
  • Forearm supination

Anterior Dislocation


Elbow flexed


Direct force to posterior forearm


 


Pathoanatomy


  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°  


 

Definitions


  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


Treatment:


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