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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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