Download Elbow arthroscopy (R)

Elbow Arthroscopy
Anatomy
The brachialis muscle lies between the capsule and the anterior neurovascular
structures.
Uses
• Diagnostic
• Can confirm PLRI, MCL insufficiency.
• Therapeutic
• Synovectomy – this can be combined with radial head excision
• Debridement of joint surfaces
• Release of adhesions, capsular release
• Excision of osteophytes
• Removal of loose bodies
• i. Up to 30% of loose bodies are not seen on plain XR
• ii. Often more loose bodies are seen at arthroscopy than are evident on
plain XR.
O'Driscoll prefers not to arthroscope patients who do not have mechanical
symptoms or specific findings on examination. He rarely finds abnormalities in
these patients.
Contraindications
Prior ulnar nerve transposition (medial portals), or ulnar nerve subluxation.
Reflex sympathetic dystrophy
Technique
Positioning
Three possible positions:
• Supine: disadvantages are restricted movement secondary to suspension
device, and relative inaccessibility of the posterior aspect of the joint
• Prone: more commonly used, because it eliminates need for traction
devices, facilitating joint mobility and portal access. Gravity helps the anterior
NV structures to fall away from the joint.
• Lateral: same advantages as prone positioning but makes things easier for
anaesthetist. Also allows easier conversion to open procedures.
Pump
Use of a mechanical pump delivering a pressure of 80-100mmHg controls
bleeding and provides a clear view of the joint.
Scopes
The 4mm standard arthroscope can be used in the anterior compartment; the
2.7mm scope is best used in the posterior compartment. Use of 30 and 70
degree scopes will enhance visualization.
Portals
Note: Green's says it is safest to start with the anteromedial portal and use an
inside out technique for the anterolateral portal.
Anterior portals
• Anterolateral – 1cm distal and anterior to lateral epicondyle. The radial
nerve is 4mm away in the undistended joint but 11mm away in the distended
joint. Was originally described 3cm distal to the lateral epicondyle but this
puts the radial nerve at too much risk.
• Proximal lateral – 2cm proximal to the lateral epicondyle of the humerus,
lying on the anterior margin of the humerus. This is the safest of the anterior
portals.
• Anteromedial – 2cm proximal and anterior to medial epicondyle. This portal
is anterior to the intermuscular septum, which protects against damage to the
ulnar nerve. The median nerve is 11mm away.
Posterior portals
• Midlateral – in the soft spot between olecranon and radial head. Portal for
infiltration
• Adjacent portal – this is adjacent to the midlateral portal, as there is 2cm of
room in the soft spot, with no major neurovascular structures here.
• Posterolateral – 2cm proximal to olecranon, just lateral to triceps tendon
• Straight posterior portal, or transtriceps portal – located 2cm proximal to
the tip of the olecranon through the centre of the triceps
The distal lateral portal is not recommended because of increased risk to the
radial nerve.
The posteromedial portal is not recommended because of increased risk to
the ulnar nerve.
How to do it
• The patient is positioned prone, with an arm board running parallel with the
bed, with a sandbag on top to keep the arm steady. The elbow is flexed to 90
degrees, a position that maximizes volume of the elbow joint and helps to
displace the anterior neurovascular structures away from the joint.
• An 18G needle is inserted into the midlateral (soft spot) portal and the joint
distended with 15-30mL of saline. The average volume capacity is 23mL but
this is reduced in elbow contractures by up to half.
• The anteromedial portal is developed first. A small incision is made anterior
to the intermuscular septum, 2cm proximal to the medial epicondyle, and the
tip of the trocar is used to palpate the intermuscular septum then slide
anterior to it. The trocar is directed towards the radial head, sliding along the
anterior aspect of the humerus.
• A lateral portal is established next. This can be the proximal lateral (safest)
or anterolateral. The proximal lateral portal is located 2cm proximal to the
lateral epicondyle, on the anterior aspect of the humerus; the trocar is slid
distally towards the medial aspect of the radiocapitellar joint.
The anterolateral portal is established using an inside out technique. The tip
of the cannula is advanced to the level of the anterior aspect of the
radiocapitellar joint, and then a rod is pushed through the capsule and then
blunt dissected down onto.
• The posterior compartment is approached directly through the soft spot; if
work needs to be done in here an 18G needle is used to find an appropriate
position for an adjacent portal.
Complications
• Compartment syndrome
• Septic arthritis (0.8% Kelly and Morrey 2001)
• Prolonged drainage, particularly in haemophiliac arthropathy
• Nerve injury (usually transient).
• The radial nerve is damaged most commonly.
• The radial nerve is particularly vulnerable from the lateral portal; the ulnar
nerve is particularly vulnerable when working in the posterior compartment.