Recurrent Posterior Instability

 

Post labShoulder Posterior Bony Block0002glen osteo

 

Overview

 

Isolated posterior labral tears 

- usually history of trauma

- often have posterior shoulder pain rather than instability

- do well with surgery

 

Recurrent posterior shoulder instability

- typically dsubluxation rather than dislocation

- often have element of ligamentous laxity / capsular stretching

- crossover with MDI

 

Savoie et al Arthroscopy 2008

- arthroscopic management of 136 shoulders with posterior instability

- 51% had reverse Bankart lesion

- 67% had posterior capsular stretching

- 15% had both

 

Pathology

 

Soft tissue Bony
Posterior labral tears Reverse Hill Sachs
Ligamentous laxity / capsular  laxity Posterior bony bankart

Posterior / reverse HAGL

Glenoid retroversion

 

Rev HSPosterior Glenoid DeficiencyShoulder Posterior Instability Glenoid Retroversion

Reverse Hill Sachs / Posterior bony Bankart / Glenoid retroversion

 

History

 

Recurrent subluxation / feelings of posterior instability

 

Traumatic posterior dislocation - MVA / seizures / electrocution

 

Posterior shoulder pain - more common than instability with posterior labral tears

 

Examination

 

Ligamentous laxity / sulcus sign

 

Posterior stress test - patient supine / adduct, forward flex and IR arm / posterior force / apprehension test

 

Load and Shift / Posterior Drawer / Altchek Gradingd

Grade 0       No translation

Grade 1+     Up to glenoid rim

Grade 2+     Beyond rim with spontaneous reduction

Grade 3+     Translation beyond rim without spontaneous reduction

 

CT

 

Rev HSpost bbPosterior Instability Glenoid Retroversion

Hill Sachs lesion / posterior bony bankart / glenoid retroversion

 

MRI

 

Posterior labral tears / bankart lesion

 

posterior labral tearShoulder MRI Posterior Labral Tear

Posterior labral tear

 

post labrumpost labrumpost labrum

Posterior labral tear

 

Kim lesion

 

Kim et al Arthroscopy 2004

- Kim lesion

- incomplete and concealed avulsion of the posteroinferior labrum

- superficial portion attached, deep portion detached

- labrum flat with loss of normal height resulting in retroversion of the chondrolabral glenoid

 

Kim lesionKim lesion

 

Posterior labral tears + cyst

 

labral cystlabral cystlabral cyst

 

www.boneschool.com/posterior-labral-cysts-suprascapular-nerve-compression

 

Posterior glenoid wear / osteoarthritis

 

Beware early posterior glenoid OA presenting as posterior labral tear

 

posterior labrumpost oaPosterior OA

 

Operative management

 

Indications

 

Pain - typical with posterior labral tears

Instability - often capsular laxity / ligamentous laxity

 

Options

 

Arthroscopic Open

Posterior labral repair +/- capsular shift

- posterior labral tears

Open capsular plication +/- infraspinatus shift

- revision procedures

- ligamentous laxity with no labral tear

Capsular plication

- no labral tear

- ligamentous laxity with posterior instability

Posterior capsule reconstruction

- revision procedures

- ligamentous laxity with no labral tear

McLaughlin procedure / Reverse remplissage

- reverse Hill Sachs

- add to above procedures

Posterior glenoid reconstruction / bone block

- posterior glenoid bone loss

- revision procedures

 

Arthroscopic posterior labral repair / capsular plication

 

Technique

 

Vumedi arthroscopic posterior labral repair video

 

Vumedi arthroscopic posterior labral repair + reverse remplissage video

 

Vumedi arthroscopic posterior labral repair + McLaughlin video

 

Vumedi arthroscopic posterior capsular plication video

 

Lateral or beach chair

- posterior cannula with anterosuperior viewing portal

- often need to insert anchors via accessory stab incision

- curved anchors very useful

- anteroinferior viewing portal useful for suture management

- posterior labral repair

- isolated capsular plication often difficult due to limited room and poor tissue

- postoperative external rotation brace useful

 

Posterior labral repair

 

Shoulder Arthroscopy Posterior Portalpost labpost lab

 

post labpost labPost lab

 

Posterior capsular plication

 

plicationplicationplication

 

Results posterior labral repair

 

Pennington et al Arthroscopy 2010

- 28 patients with isolated posterior labral tears undergoing arthroscopic labral repair

- all had history of trauma to shoulder

- 26/28 (93%) satisfied and returned to sport

 

Results posterior shoulder instability

 

Bradley et al AJSM 2013

- 200 shoulders with unidirectional posterior instability

- treated with capsulolabral repair / plication

- 90% return to sport

- better outcome with capsule plication with anchors versus capsule plication without anchors

 

Open posterior capsular plication

 

Indication

 

Revision instability surgery

 

Technique

 

AO surgical foundation posterior approach glenoid / scapula

 

Lateral Position

- vertical incision over glenohumeral joint

- elevate deltoid or split deltoid

- interval: between supraspinatus and infraspinatus

- interval: between infraspinaus and teres minor

- can detach infraspinatus tendon and elevate off capsule

- suprascapular nerve 1.5cm medial to glenoid

- axillary nerve below teres minor

- perform capsular plication / capsular shift

- +/- lateral advancement of infraspinatus

 

post plicationpost capsuleShoulder Posterior Approach

 

post plicationpost plicationpost shoulder

 

Posterior glenohumeral capsule reconstruction with allograft

 

Indication

 

Recurrent posterior instability

Ligamentous laxity

 

Technique

 

Arthroscopic posterior capsule reconstruction with acellular dermal allograft PDF

 

Open posterior capsular reconstruction with acellular dermal allograft PDF / video

 

Posterior glenoid reconstruction / bone block procedure

 

Indication

 

Posterior glenoid bone loss

Revision posterior instability

 

Failed Posterior Arthroscopic Shoulder Stabilisation0001Failed Posterior Arthroscopic Shoulder Stabilisation0002

 

Posterior Glenoid Deficiencypost bb

 

Critical posterior glenoid bone loss

 

Arner et al AJSM 2021

- compared successful posterior labral surgery with unsuccessful

- 11% glenoid bone loss - 10 x failure rate

- 15% glenoid bone loss - 25 x failure rate

 

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Technique

 

Arthroscopic posterior glenoid reconstruction technique

 

Open posterior glenoid reconstruction PDF

 

Open posterior glenoid bony reconstruction PDF

 

Beach chair or lateral position

- posterior approach / L shaped incision

- elevate or detach deltoid from scapular spine

- detach infraspinatus

- iliac crest or distal tibial allograft

 

post approachpost approachpost approach

Identify and elevate deltoid / detach from scapular spine / identify infraspinatus

 

glenoid osteotglen osteotglen osteo

Identify interval between infraspinatus and teres minor, detach and reflect infraspinatus to expose posterior capsule and glenoid

 

Shoulder Posterior Bony Block0001Shoulder Posterior Bony Block0002

 

Results

 

Mojica et al JSES 2021

- systematic review of posterior glenoid bone block for posterior instability

- 11 studies and 225 shoulders

- recurrent instability 10%

- complications: 11% hardware, 0.5% wound, 0.5% nerve

- residual pain 12%

 

Glenoid Osteotomy

 

Indication

 

Posterior instability with retroversion > 10 degrees / glenoid dysplasia

Young patient with no osteoarthritis

 

glen retroglenoid retroglen retro

 

Technique

 

Arthroscopic glenoid osteotomy technique PDF

 

Beach chair or lateral

- posterior approach / detach deltoid / tentomy infraspinatus

- capsulotomy to expose glenoid

- osteotomy parallel to articular surface, 1.5 cm from articular surface

- preserves anterior 1 cm of glenoid to prevent iatrogenic fractures

- open 4 - 5 mm and insert bone graft

- +/- fixation

 

glen osteoglen osteoglen osteo

 

glen osteoglen osteoglen osteo

 

Results

 

Hinz et al KSSTA 2025

- 9 glenoid osteotomies for posterior shoulder instability

- good functional outcome and reduction in pain

- residual instability in 75%

- osteotomy did not recenter humeral head

- progression of osteoarthritis continues

 

Waltenspul et al JSES 2022

- 7 glenoid osteotomies for posterior shoulder instability

- 4/7 good or excellent results

- residual instability in 6/7 (86%)

- 5/7 patients osteotomy did not recenter humeral head

- 100% progression of osteoarthritis continues