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Posterolateral Elbow Rotatory Instability (PLRI)

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Topic updated on 08/22/16 1:46pm
Introduction
  • Traumatic varus stress may result in isolated injury, but most injuries involve spectrum of pathology following elbow dislocation 
  • Mechanism
    • traumatic
      • most often discussed in the setting of posterolateral rotatory instability (PLRI)
        • combination of forearm supination, axial loading, valgus (posterolateral) stress, and elbow extension results in posterior subluxation of radial head and rotation of semilunar notch away from trochlea 
    • iatrogenic injury
      • may  occur from arthroscopic or open procedures involving lateral elbow
      • arthroscopic debridement should be kept anterior to equator of the radial head
    • chronic attenuation
      • secondary to chronic cubitus varus malunion also described
Anatomy
  • Lateral collateral ligament complex consists of 4 components 
    • lateral (radial) collateral ligament (LCL)
    • accessory lateral collateral ligament
    • annular ligament 
    • Lateral ulnar collateral ligament (LUCL) is primary stabilizer to varus & ER stress
      • ulnar portion of the lateral (radial) collateral ligament (LCL)
      • originates at the lateral humeral epicondyle and inserts on the tubercle of the supinator crest of the ulna
      • Posterolateral rotatory instability is caused by insufficiency to an important lateral stabilizer
Presentation
  • Symptoms
    • pain is the primary symptom
    • PLRI patients complain of mechanical symptoms (clicking, catching, etc.) with elbow extension, e.g. pushing off from arm of chair
  • Physical exam
    • varus instability
    • tenderness over LUCL
    • lateral pivot-shift test   
      • patient lies supine with affected arm overhead; forearm is supinated and valgus stress is applied while flexing the elbow
      • often more reliable on anesthetized patient
    • apprehension test
      • patient lies supine with affected arm extended overhead; forearm is supinated and valgus stress is applied while flexing the elbow
    • chair rise test 
    • table-top relocation test
    • floor push-up test also described
Imaging
  • Radiographs
    • recommended views
      • AP and lateral views of elbow
    • findings
      • important to rule out associated fractures and confirm concentric reduction in setting of acute dislocation 
      • standard radiographs are often of little value in evaluating PLRI
        • fluoroscopic imaging during provocative testing (e.g. pivot-shift) may demonstrate radial head subluxation
  • MRI
    • can identify acute avulsion of LUCL in acute instability
      • may not be helpful in the setting of recurrent instability and LUCL attenuation
Treatment
  • Nonoperative
    • acute reduction followed by immobilization for 5-7 days 
      • indications
        • acute dislocations
      • technique
        • following reduction assess post-reduction stability
        • place in posterior splint for 5-7 days, with elbow at 90 degrees of flexion and forearm appropriately positioned based on post-reduction stability
          • LCL disrupted, but MCL intact 
            • splint in full pronation
          • LCL intact, but MCL disrupted
            • splint in full supination
        • early active range-of-motion following splint removal (+/- extension block)
          • full supination/pronation from 90 degrees to full flexion
          • progress with increasing extension by 30 degrees weekly, but with the forearm in full pronation; after 6 weeks full supination in extension allowed
  • Operative
    • open reduction, fixation, ligament repair
      • indications
        • osteochondral fragment or soft-tissue entrapment prevents concentric reduction
        • complex dislocation (associated fractures are present)
        • acute instability may be treated with repair
          • open & arthroscopic techniques described
    • LUCL reconstruction
      • indications
        • elbow stability cannot be achieved with reduction and immobilization
        • PLRI 
Techniques
  • Reconstruction of LUCL complex
    • techniques
      • graft types
        • autograft or allograft tissue may be used
          • palmaris longus most common
      • graft configuation
        • originally utilized tendon graft tied to itself over lateral column after placing through tunnel in supinator crest & then weaving through "Y" tunnel configuration in humerus
        • it is critical that the graft covers at least the posterior 25% of the radial head to create a sling
        • graft can be plicated to capsule to maintain position and capsule plicated to augment repair 
        • graft secured with arm in neutral rotation and 45 degrees of flexion
      • graft fixation
        • graft may be "docked" on humerus with sutures exiting "Y" tunnels or on both humeral and ulnar sides with interference screws (or sutures tied over bone)
      • coronoid fracture / anterior capsular laxity
        • large fragments should be fixed by a screw from dorsal ulnar surface (aided by ACL type guide to improve accuracy
        • small fragments should be excised but a suture plication of the anterior capsule to the broken tip increases stability and can be placed with the aid of ACL type guide
    • postoperative
      • protected from varus stress across the elbow and shoulder abduction post-operatively (locked hinge brace)
      • early range-of-motion encouraged (+/- extension block with progressive gain to full extension by 6 weeks)
      • important to keep forearm in full pronation during ROM until after 6 weeks (as above)

 

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Qbank (3 Questions)

TAG
(OBQ13.88) A 23-year-old male sustains a dislocation of his elbow that was successfully closed reduced in the emergency room. 3 months later, the patient presents with pain and a catching sensation in his elbow. On physical exam, he is noted to have a positive lateral pivot-shift test. Incompetence of which of the following ligaments in Figure A is most commonly associated with his condition? Topic Review Topic
FIGURES: A          

1. A
2. B
3. C
4. D
5. E

PREFERRED RESPONSE ▶
TAG
(OBQ11.244) A 24-year-old male sustains the right elbow injury shown in Figures A and B. He promptly undergoes operative irrigation and debridement, reduction, vascular bypass of the brachial artery, and hinged elbow fixator placement for 6 weeks. Three years later he complains of clicking and locking with elbow extension and difficulty performing arm triceps dips while attempting exercise. He is unable to perform a pushup. Which of the following reconstruction procedures is MOST appropriate? Topic Review Topic
FIGURES: A   B        

1. Elbow arthroscopy with extensor tendon insertion debridement
2. Lateral ulnar collateral ligament reconstruction with palmaris tendon graft
3. Radial collateral ligament reconstruction with palmaris tendon graft
4. Medial ulnar collateral ligament reconstruction with palmaris tendon graft woven in a figure-eight fashion (Tommy John procedure)
5. Medial collateral ligament reconstruction with palmaris tendon graft woven using Docking procedure

PREFERRED RESPONSE ▶
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