Multidirectional Instability

DefinitionMDI Shoulder


Instability in at least 2 planes

- postero-inferior

- antero-inferior

- antero-postero-inferior




Recognised as a common problem 

- often misdiagnosed


Most patients athletic

- average age 24 years (15 - 54 years)




1.  Inherent ligament laxity > 50%


2.  Repetitive overuse with capsular stretch 

- microtrauma


3.  Macro-trauma < 50%




Collagen abnormality


Increased joint volume 

- 2° enlarged inferior axillary capsular pouch

- patulous anterior and posterior


Often attenuated, broad rotator interval




Often bilateral


Instability of other joints


Feeling of shoulder "slipping down" while carrying heavy loads

- inferior instability


Often recurrent subluxation with minimal trauma

- sleeping


Shoulder pain

- fatigue 

- impingement type pain with overhead activities




Ligamentous laxity 75%


Inferior instability

- Sulcus Sign +


Shoulder Sulcus Sign


Anterior instability

- anterior draw

- anterior load and shift

- anterior apprehension, positive Jobe's relocation


Posterior instability

- posterior draw

- posterior load and shift

- posterior apprehension / jerk test




Traction xray

- patient standing with 5-10 kg in each hand

- Shows inferior subluxation of head


DDx of Inferior displacement of head


Torn superior rotator cuff

Suprascapular nerve palsy

Deltoid atony eg CVA

Deltoid / axillary nerve palsy






Mainstay of treatment

- operative results poor




Minimum 12/12

- initial shoulder strengthening

- strengthen 3 parts of deltoid, cuff & scapular stabilisers

- specific programme with rope & pulleys

- combined with education program

- ~ 90 % success





- never operate on voluntary dislocator

- MDI surgery less successful than surgery for unidirectional instability

- cannot perform isolated anterior surgery

- bristow procedures etc fail as capsule remains redundant 

- anterior surgery may displace head posteriorly


MDI with traumatic anterior bankart

- new symptomatic instability on a background of ligamentous laxity / MDI

- MRA diagnosis of anterior bankart

- is reasonable to operate on patient with new traumatic anterior instability with labral tear

- issue is whether to combine with capsular shift


Options for MDI


1. Neer and Foster inferior capsular shift

2. Arthroscopic capsular plication


1.  Open Inferior Capsular Shift ~ Neer & Foster 1980


MDI SubluxedMDI Reduced



- detach capsule from neck of humerus

- shift capsule superiorly to obliterate the inferior pouch

- decrease joint volume





- to confirm diagnosis


Deltopectoral Approach / Axillary fold



- must divide SSC separate to capsule

- need to leave capsule intact

- make horizontal incision in inferior border of SSC

- at muscular aspect

- insert curved artery forcep between SSC and capsule

- will exit at rotator interval

- insert medial stay sutures x 2 (use different colour to differentiate from capsular sutures)

- make vertical incision on artery forcep to avoid injury to capsule


T shape capsulotomy of capsule

- vertical component on humeral insertion

- transverse component to midpoint glenoid

- mark with pen first

- make vertical component on articular margin

- place inferior and superior stay sutures

- make horizontal incision

- creates superior and inferior capsular flaps


Capsular Shift 1Capsular Shift 2


Inspect joint

- ensure no loose bodies

- repair bankart lesion if needed


Inferior capsular flap

- must sharp dissect capsule off inferiorly around humeral head

- protect AXN at all times

- do so by following articular margin around

- ER shoulder +++

- must get past 6 o'clock into posterior aspect

- check that traction on interior flap reduces inferior capsular pouch


Superior advancement inferior capsular flap

- tension on flap aimed at eliminating inferior pouch

- must reduce posterior capsular redundancy

- multiple 0 pull off stay sutures through flap and into remnant humeral tissue

- +/- anchors

- begin inferiorly, care with AXN

- cut and clip each sutures

- then tie all sutures togther at end


Capsular Shift 3Capsular Shift 4


Check ER

- arm adducted, check ER 45o

- arm abducted to 90o, check ER 45o


Superior flap sutured down over inferior flap

- again multiple 0 pull off sutures

- tie

- check ER as above


Check not too tight

- can dislocated posteriorly


Closure of RI

- check ER as above


Subscapularis tendon brought over & reattached to normal location

- check ER as above


Post op

- Arm immobilised in sling 6/52

- No sport for 9/12 




Bigliani et al JBJS Am 2000

- 52 shoulders with open inferior capsular shift

- approach posterior or anterior depending on greatest instability

- 96% remained stable at average 61 months

- 60% excellent and 30% good results

- 70% athletes able to return to sport at same level


Ogilvie-Harris Br J Sports Med 2002

- contact athletes

- antero-inferior capsular shift in 37 with 3 recurrences (8%)

- posterior-inferior capsular shift in 16 with 2 recurrences (1 anterior / 1 posterior)(12%)

- 80% return to sport in antero-inferior capsular shift

- 75% return to sport in postero-inferior capsular shift

- only 17% return to sport if bilateral procedures


MDI Pre Capsular ShiftMDI Post Capsular Shift


2.  Arthroscopic






View via posterior and anterosuperior portal

- labrum is attached

- capsule very lax


Capsular laxity 1Capsular laxity 2Intact anterior capsule and labrum


Anterior plication

- use shaver to create capsular stimulation

- don't remove or resect capsule


Option 1

- pass through capsule, then through labrum
- inferior suture first

- take bite of anterior inferior capsule with suture passer

- advance suture passer

- then pass separately through anterior labrum at a more superior level

- tie

- repeat x 2


MDI Anterior Capsular PlicationMDI Anterior Capsular Plication 2MDI Anterior Capsular Plication 3


MDI 2 bites anterior capsuleMDI 3 x anterior capsular sutures



Option 2

- anchor in glenoid

- pass stures throught capsule and labrum


Capsular laxityCapsular plication with suture anchorsCapsular laxity post plication with suture anchor


Posterior plication

- camera inserted via anterior portal

- insert posterior cannula

- repeat inferior posterior sutures x 3


MDI Posterior capsular plication


May suture rotator interval if needed




Baker et al Am J Sports Med 2009

- 43 patients average age 19 years

- 86% return to sport


3.  Thermal Capsular Shrinkage


Recognised as poor procedure




Miniaci et al JBJS Am 2003

- 19 patients with MDI

- 9 recurrent instability

- 4 had parasthesia in AXN, one had deltoid weakness, all resolved

- worse results in posteroinferior compared with anteroinferior