arthroscopy

indications

Diagnostic

· provide information regarding shoulder instability

· in place of or in addition to radiographic methods

· assess rotator cuff

· glenohumeral side

· subacromial side

· investigate cause of pain or other symptoms

Therapeutic

· shoulder stabilisation

· acromioplasty

· synovectomy

technique

Preparation

· place patient in lateral position

· tilt posteriorly 30^o so that glenoid is parallel with bed

· stabilise patient with beanbag or lateral rests

· apply skin traction to forearm

· place traction pole at foot of table opposite surgeon

· suspend arm with 5-10 lb weight

· abduction 45-60^o

· forward flexion of 20^o

· outline bony landmarks

· prep and drape patient

Posterior portal

· identify posterolateral corner of acromion

· identify soft-spot

· 1 cm medial and 2 cm inferior

· insert spinal needle into glenohumeral joint

· direct tip towards coracoid

· inject small amount of saline

· confirm position by backflow

· distend joint with 50 ml saline

· make stab wound at posterior portal

· introduce cannula and trocar

· confirm position with back-flow

· introduce arthroscope

Examination

· initial orientation is (for right shoulder)

· biceps tendon to left 10-15^o from vertical)

· glenoid to right inferiorly

· humeral head to right superiorly

Biceps tendon and groove

· trace tendon

· from superior attachment to glenoid

· to where enters bicipital groove

Rotator cuff

· supraspinatus tendon is seen upwards above tendon

Glenoid

· is seen posteriorly below tendon

· inspect surface and labral rim

Inferior recess

· revealed by continued inferior rotation of scope

Humeral head

· can see all but anterior part of head

· may see bare patch posteriorly between articular surface and capsular insertion

Anterior labrum

· scope passed anteriorly

· brings anterior labrum into view

Anterior portal

· direct scope into intra-articular triangle

· biceps tendon

· head of humerus

· glenoid labrum

· advance until rests aginst anterior capsule

· light transilluminates skin at site of portal

· remove scope from sheath

· insert rod through sheath

· make stab incision

· advance rod

· use portal for probe and instruments

Subacromial portal

· pass blunt obturator through posterior portal

· direct it superiorly immediately below acromion

· introduce arthroscope

neurological complications

· uncommon (0.1%)

Direct injury

Posterior portal

· passes between infraspinatus and teres minor

· is 3-4 cm superior to quadrangular space

Anterior portal

· pierces deltoid

· enters between subscapularis and supraspinatus

· is lateral to coracoid

· structures at risk

· musculocutaneous nerve

· subscapular nerves

· structures at risk if portal incorrectly placed medially

· brachial plexus

· axillary artery and vein

Other portals

· suprascapular fossa portal

· suprascapular nerve at risk

· lateral portal

· axillary nerve at risk

Procedures

· Bankart repair

· suture through drillhole from anterior glenoid into infraspinatus fossa

· suprascapular nerve may be injured by drill or suture passer

· debridement of AC jt

· brachial plexus may be injured if debridement carried too far medially

Neuropraxia

· associated with traction on arm

· may affect

· musculocutaneous nerve

· ulnar nerve

· remainder of brachial plexus

· radial nerve at wrist

· may be minimised by

· arm in 15^o flexion and 70^o abduction

· traction of < 20 lb

· beach chair position

Nerves

Musculocutaneous nerve

· at greatest risk

· from

· anterior portal

· traction

· fluid extravasation