Posterolateral rotatory instability

Definition

Dynamic posterior instability of the radial head relative to the capitellum in flexion

Secondary to injury to the Lateral Collateral Ligament (LCL) complex

Anatomy LCL complex

LCL Elbow

Four components

Need injury to lateral UCL and radial collateral ligament for instability to occur

Lateral Ulna Collateral Ligament	Radial Collateral Ligament	Accessory Collateral Ligament	Annular ligament
Lateral epicondyle to supinator crest	Lateral epicondyle to annular ligament	Lateral epicondyle to annular ligament and supinator crest	Anterior and posterior sigmoid notch
Most important

Etiology

Trauma

- elbow dislocation

- LCL complex fails to heal

Iatrogenic - tennis elbow release / Kocher approach

Ligamentous laxity

Cubitus varus

History

Lateral elbow pain

Clicking

Instability

Examination

Combine external rotation / supination with valgus and axial loading

Pivot Shift Test
Patient supine with hand over head - examiner at head of bed - elbow fully extended and forearm supinated - elbow resembles knee in this position Valgus stress with axial load & slowly flex elbow - at 30 - 45^o the radial head subluxes posterolaterally - patient feels apprehension / pain - reduces as the elbow flexes more

Pivot Shift Test

Patient supine with hand over head

- examiner at head of bed

- elbow fully extended and forearm supinated

- elbow resembles knee in this position

Valgus stress with axial load & slowly flex elbow

- at 30 - 45^o the radial head subluxes posterolaterally

- patient feels apprehension / pain

- reduces as the elbow flexes more

pivot shift

Table top test
Push up on table with forearms in supination - in flexion the radial head subluxes - patient has apprehension and pain	Pain and apprehension relieved by anterior pressure on radial head

Table top test

Push up on table with forearms in supination

- in flexion the radial head subluxes

- patient has apprehension and pain

Pain and apprehension relieved by anterior pressure on radial head

Pivot Shift Test
Patient supine with hand over head - examiner at head of bed - elbow fully extended and forearm supinated - elbow resembles knee in this position Valgus stress with axial load & slowly flex elbow - at 30 - 45^o the radial head subluxes posterolaterally - patient feels apprehension / pain - reduces as the elbow flexes more