Instability of the Elbow Treated with Semiconstrained Total

Elbow Arthroplasty

From: Ramsey, Adams, and MorreyU. of Pennsylvania

Presented By: Adam Morse, D.O.

Introduction

• The elbow is a ginglimus joint which serves as a fulcrum of the upper extremity

• It allows the hand to be positioned in space• Loss of the normal elbow function can result

in a functionally useless extremity, as in a flail elbow

• Gross instability of the elbow is a challenging clinical situation

Elbow Instability: Etiology• Causes of Gross instability include

– nonunion of supracondylar/intracondylar fractures– nonunion of epicondylar avulsion injury– Severe rheumatoid destruction of the elbow– Loss of bone following trauma, infection or excision– Reconstruction with allograft,– Arthrodesis– S/P total elbow arthroplasty

The Study Design• Retrospective review of 21 patients with 21 elbows, 2

died, 19 evaluated• Evaluated 25-128 months post-op (ave 72)• Coonrad-Morrey prosthesis (Zimmer, Warsaw,

Indiana)• 2 men, 17 women, ave age 61 (22-81) 14 patients s/p

distal humerus fracture, 11 s/p ORIF, 2 casted, and 1 Ex-Fix

• 2 pts with RA, 1 severe crush injury, 1 infection

Operative Technique• Triceps was released subperiosteally in 10 patients

and a triceps sparing approach was used thereafter.• The ulnar nerve was translocated anteriorly if not

already performed in a previous operation• If significant contracture existed, humeral shortening

can be performed up to 2 cm without weakening the triceps

• Attempt to acheive at least 30-130 degrees of motion, although full motion is desired

Operative Technique

• The ulnar component is inserted first with the use of an intramedullary cement injecting system using Tobramycin impregnated polymethylmethacrylate

• The common flexors and extensors are sutured to the triceps fascia

• No splinting or casting is used in the immediate postoperative period

The Implant

• The modified Coonrad-Moorey implant is ideally designed for use when there is distal humeral bone loss

• The axis of rotation of the implant is coincident with the native axis of rotation

• The axis of rotation reference is the depth of incertion of the implant relative to the roof of the olecranon fossa, not relative to the joint line

The Implant

• Therefore the axis is restored even if there is an osseous defect in the roof of the olecranon fossa

• In fact, shortening of the humerus 2 cm proximal to the olecranon fossa (4-5cm of distal humerus) is acceptable with this implant

Patient Evaluation

• The Mayo Elbow Performance Score was used to document subjective, objective, and functional characteristics, pre and post operatively

• Performance index for pain(0-45 pts), motion(0-20 pts), stability(0-10 pts), and ADLs(0-25 pts)

• Post op score >90=excellent, 75-89=good, 60-74=fair, <60=poor

Radiographic Evaluation

• Pre/intraoperative bone loss was graded 1-4– grade 1= damage to articular surface with intact

trochlea and capitellum– grade 2= absence of the trochlea with intact medial

and lateral epicondyles– grade 3= absence of either the medial or lateral

epicondyles – grade 4= absence of medial and lateral epicondyles

Radiographic Evaluation

• Postoperative x-rays were evaluated for – 1) incorporation of bone graft behind the anterior

flange of the prosthesis• classified as resorbed, incomplete, mature

– 2) progressive radiolucency about the bone cement interface

• classified type I-V – 3) evidence of wear of the bushings

• demonstrated by valgus angle > 7 degrees

Results

• Mayo score excellent in 10, good in 6, 3 were fair or poor

• Average preoperative score was 44 compared to 86 postoperatively at most recent follow up. Significance p < 0.001

• Preoperatively all patients had instability, and postoperatively no patient had instability

Results

• Range of motion– Preoperatively all 19 patients had a functionally

useless ROM (0 degrees for 9 flail elbows) and (ave 26-113 degrees for the 10 grossly unstable elbows)

– Postoperatively the ROM increased to an average of 19 to 131 degrees

– preoperative arc of motion changed from 25 degrees to 128 degrees (p < 0.001

Results

• Pain Relief– Average pain score preoperatively was 25

points and postoperatively increased to 37 at most recent follow up exam

• 12 patients had no pain• 4 had mild pain• 3 had moderate pain• no patient had severe pain pre or post operatively

Results• Activities of daily living

– Average preoperative score was 7, average postoperative score was 22

• Radiographic evaluation (preoperative)– 1 patient with grade 3 bone loss– 18 patients with grade 4 bone loss

• Radiographic evaluation (postoperative)– bone graft was resorbed in 2 pts, incomplete in 2 pts

and mature in 14

Results

• Radiographic evaluation (postoperative)– Radiolucency was evaluated in 15 patients, 14

were type 0, and 1 was type V, necessitating revision of the humeral component

– Bushing wear was checked in 9 patients none of which had an intersection angle > 7 degrees

Results• Complications

– 1 intraoperative complication and 3 postoperative complications were seen in 4 pts

– The intraoperative complication was an olecranon fracture in a rheumatoid patient

– Postoperative complications included loosening of a humeral component and fracture of 2 ulnar components, one in a fall and one when lifting 100 lb feed bags

– All postoperative complications required revision

Discussion• Several authors have reported good results with TEA

in OA, RA, or Trauma principally for pain, but this was the first study whose principal indication was gross instability

• In pts with nonunion of distal humerus fractures, revision ORIF and bone grafting is the gold standard, but in pts with advanced age, limited activity requirements, distal humeral bone loss, and irreversible articular damage, TEA may be a better option

Discussion• In patients with significant bone loss treatment

options are limited– Arthrodesis relieves pain and restores stability,

although it may be difficult to achieve when significant bone loss exists, and a successful arthodesis limits a pts ability to perform ADLs

– Allograft reconstruction of the distal humerus has been used, however, serious complications including nonunion, and graft resorption have prevented it’s widespread use

Discussion• In several of the patients TEA was performed

because of a lack of alternative reconstructive options allowing the stability and motion of this procedure

• Although 2 ulnar component fractures were seen, one while lifting 100 lb bags,this attests to the lack of pain and increased stability of the implant

• the ulnar component has since been redesigned with no fractures reported since

Discussion

• While flail or grossly unstable elbows present many difficult challenges, the outcome of semiconstained TEA is very rewarding

• From a useless extremity preoperatively that cannot be positioned in space, arthroplasty creates a stable fulcrum for motion postoperatively with a functional extremity