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Elbow replacement _R_

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					                             Total elbow arthroplasty
Indications
Pain relief
Ideally inflammatory arthritis involving multiple joints
Unreconstructable intra-articular distal humeral fracture in elderly patient
Low demand, elderly patient

Contraindications
Infection
Neuropathic arthropathy
Young patient unprepared to modify activities

Classification of prostheses
1.      Unconstrained and unlinked – eg Kudo, Ewald capitellocondylar, Souter Strathclyde
2.      Semiconstrained and unlinked
3.      Semiconstrained and linked – eg Coonrad Morrey. This has 10 degrees of varus/valgus
        laxity, and some rotational laxity built into it. GSB III is another example.
4.      Semiconstrained, option of linked or unlinked
5.      Constrained – these have been consigned to the dustbin because of unacceptably high
        rates of loosening.

Unconstrained implants are less prone to loosening because the surrounding soft tissues absorb
forces, but they have a 5-20% rate of instability problems. They can be considered in the younger
patient (<60) with an adequate soft tissue envelope and well preserved bone stock. They are
usually stemmed, as earlier unstemmed resurfacing prostheses had a high rate of posterior
displacement. The capitellocondylar prosthesis (Ewald) is the oldest TER prosthesis on the
market and has good results in his hands, with only a 1.5% rate of loosening, but in
unexperienced hands the dislocation rate is very high. The recommended approach is lateral to
preserve the anterior oblique band of the MCL. The radial head is resected.

The most reliable implant at present is the linked semiconstrained design, which appears to be
sloppy enough to transfer forces to the soft tissues and prevent early loosening.

Consideration of other joints
If both shoulder and elbow are involved, O’Driscoll recommends doing the more symptomatic
joint first. Make sure that short humeral stems are used.

The results of shoulder and elbow replacements in the same limb are similar to single joint
replacements.

O’Driscoll says his early results with bilateral TERs are encouraging.

Patients with lower limb pathology should have these joints addressed prior to TER because they
will need crutches to rehabilitate.

Technical notes
The access is posteriorly.
The ulnar nerve should be transposed.

If an unconstrained component is used careful soft tissue balancing is mandatory, including
repair of the LUCL.

Dee and Hurst advocate the routine use of antibiotic impregnated cement, which has been shown
to dramatically decrease the risk of infection in the TER patient. Geoff Hughes inserts a cannula
and injects Keflin after the tourniquet has been elevated.

Postoperative care
With unconstrained prostheses the ligaments must be allowed to heal, with several weeks of
postoperative immobilization; with semiconstrained prostheses early ROM is possible, within 36
hours.

In the long term, if the olecranon is prominent the patient should be instructed to wear a pad
over the olecranon to prevent bursitis, as an infected bursa may communicate directly with the
joint.

A weight restriction of 3kg is placed on the arthroplasty.

Results of Coonrad-Morrey TER
92% survival rate at 10 years in a group of predominantly rheumatoid patients (Gill and Morrey
JBJSB 1999). These patients enjoyed substantial pain relief and restoration of function in over
90%. Bushings worn in up to 10% of patients.

Typically, preoperatively there is a 70 degree flexion arc and a 90 degree rotation arc;
postoperatively there is a 100 degree flexion arc and a 130 degree rotation arc. Gains in motion
are greater with semiconstrained prostheses, because superior soft tissue releases are possible.

In patients with primary OA, implant failure and loosening required revision in nearly 50% at 3
years.

Complications
Most devastating is complete removal leaving a flail arm.
Infection – usually revision is unsuccessful if the organism is S.epidermidis.
Triceps weakness and insufficiency. If there is a sudden abrupt decline in function then
exploration and reattachment of the triceps is indicated.
Ulnar nerve neuritis and palsy in up to 25% of patients.

Coonrad-Morrey TER - Zimmer
Design points
Has an anterior flange, under which a bone graft is wedged, to increase rotational stability and
resist posteriorly directed forces associated with loosening.

Titanium stems and bodies, UHMWPE bushings with Co-Cr locking pin.

Comes in 4, 6 and 8 inch lengths. The longest prosthesis should be used, unless a shoulder
arthroplasty is present or likely to be needed, in which case the 4 inch prosthesis should be used.
In these patients a bone plug should also be inserted in the humerus to prevent proximal cement
migration.

Technique
1.     Supine positioning, arm placed across the chest. TQ.
2.     Incision is 15cm long, just medial to olecranon.
3.     Identify medial aspect of triceps mechanism, and ulnar nerve. Free up ulnar nerve,
       translocate anteriorly and mark with nerve tape.
4.     Make an incision along the ulnar border of the ulna and elevate the ulnar periosteum
       along with the forearm fascia. Release the triceps in continuity with its fascial insertion
       and sublux the entire extensor mechanism laterally. Release the anconeus medially.
       Note: some advise taking a flake of bone off the olecranon, but this has a high nonunion
       rate according to O’Driscoll.
5.     Saw off the tip of the olecranon.
6.     Release the humeral attachments of the collateral ligaments.
7.     Dislocate the joint medially.
8.     Remove a disc of bone from the mid portion of the trochlea, to allow access to the
       humeral IM canal and provide the bone graft to place under the flange. The bone graft
       should be 2-3mm thick, 1.5cm long and 1cm wide.
9.     Use a burr to enter the IM canal through the roof of the olecranon fossa.
10.    Ream out the humeral canal
11.    Place alignment guide into canal, place cutting block on guide and rest on the capitellum
       to provide the appropriate depth
12.    Make the vertical cuts on either side of the block first, then the oblique cuts. Be very
       careful to avoid notching into either supracondylar column.
13.    Rasp the humeral canal
14.    Release the anterior capsule and brachialis from the anterior distal humerus to provide a
       place for the bone graft
15.    Use the burr to enter the ulna
16.    Start with the starter awls, finish with the pilot rasp.
17.    Trial reduction
18.    Prepare for cementing; the cement must be introduced early to provide plenty of time for
       inserting both prostheses
19.    The ulnar component should be inserted as far distally as the coronoid process. The
       centre of the ulnar component should align with the projected centre of the greater
       sigmoid notch.
20.    Cement the humeral component, placing the bone graft under the anterior flange.
21.    Put in the articulating pin and seat the humeral component
22.    Repair the triceps mechanism with heavy non-absorbable sutures.

				
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