Definition
Radius rotates externally in relation to the ulna
- posterior displacement of the radial head relative to the capitellum
- in flexion
Anatomy LCL
Pathology
1. Laxity or tear of ulna LCL
- posterior dislocation / subluxation / perching
- most common cause
2. Torn CEO
- dynamic restraint
3. Depressed fracture of radial head / malunion coronoid fractures
- leading to loss of secondary restraint
Mechanism
Dislocation occurs with a valgus ER force pivoting the elbow on the intact MCL
Aetiology
Trauma
- acute LCL tear after dislocation
Iatrogenic
- tennis elbow release
- Kocher approach
Ligamentous laxity
Long standing cubitus varus
History
Posterolateral elbow pain
Describe clunk on full extension
Patient may be able to demonstrate instability
Examination
Test combines external rotation / supination with valgus and axial loading
1. O'Driscoll Pivot Shift Test
Best with patient anaesthetised
- can sublux joint
If patient awake, only get pain and apprehension
Patient supine
- examiner at head of bed
- GHJ full flexed with hand over head
- elbow resembles knee in this position
- forearm supinated
- elbow fully extended
Valgus stress with axial load & slowly flex joint
- at 40o the radial head is subluxed maximally posterolaterally
- radial head becomes prominent as it dislocates
- patient feels apprehension as the radial head subluxes
- past 40o flexion the radial head reduces
Positive
- prominent radial head (dislocates)
- pivot
- pain (apprehension)
- maximum subluxation is at 40o flexion but with increased flexion reduces with snap
2. Table Top Test
Push up on table with forearms in supination
- radial head subluxes, patient has apprehension
- relieved by thumb pressing on radial head
X-ray
Usually normal
- may be slight widening of radiohumeral joint
- radial head may appear slightly posterior
MRI
Difficult to distinguish lateral complex
Management
NHx
Does not improve with time
- usually requires surgery if very symptomatic
Options
1. Repair
2. Imbricate
3. Reinforce/Reconstruct with PL graft
Reconstruction
Kocher approach between Anconeus & ECU
- drill holes x 2 base sublime tubercle
- drill holes x 2 at lateral epicondyle (isometric point)
- palmaris graft in figure of 8
- tighten with elbow at 30 - 40o of flexion
Post op
- hold flexed 2/52
- then allow ROM in hinged brace
Results
O'Driscoll et al JBJS Br 2005
- retrospective review of 44 cases
- some direct repair, some autograft reconstruction
- 86% satisfaction
- better outcomes in reconstruction group