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J Shoulder Elbow Surg (2010) 19, 376-383

1058-2746/2010

doi:10.1016/j.jse

www.elsevier.com/locate/ymse

Outcome of total elbow replacement for rheumatoidarthritis: Single surgeon’s series with Souter-Strathclydeand Coonrad-Morrey prosthesis

Narayana Prasad, MBBS, MS, MRCS*, Colin Dent, MS, FRCS

University Hospital of Wales, Cardiff, United Kingdom

Background: The reported outcome of total elbow replacement is inferior to hip and knee arthroplasty, andthere might be an element of institutional bias.Methods: We analyzed the outcome of Souter and Coonrad-Morrey total elbow prosthesis in rheumatoidelbow performed by a single surgeon from a center independent from standpoint of being involved in thedesigning or manufacturing of the implant.Results: We had 44 Souter elbows with a mean follow-up of 108 months and 55 Coonrad-Morrey elbowswith mean follow-up of 60 months. The Mayo Elbow Performance Score was comparable in both thegroups with similar subjective satisfaction. Souter elbow showed a survivorship of 92.9% at 5 years and76% at 10 years, with aseptic loosening rate of 18% and instability of 9% as main reasons for the failure.The Coonrad-Morrey elbow shows 100% survival at mean follow-up of 5 years in our series.Conclusion: We find high rate of instability and loosening of Souter prosthesis with an inferior 5-yearsurvival compared to Coonrad-Morrey prosthesis.Level of evidence: Level III; Case-Control Series; Treatment Study� 2010 Journal of Shoulder and Elbow Surgery Board of Trustees.

Keywords: Elbow arthroplasty; rheumatoid arthritis; Coonrad-Morrey; Souter

Total elbow replacement (TER) has emerged as a real-istic option for the management of painful arthritic elbowjoint in rheumatoid arthritis. The reported outcomes of totalelbow replacement are not as good as hip or kneereplacements and the published studies are smaller.15 Ahigh proportion of the series on total elbow replacementappears to be from the institutions of the designers of theimplant.8 Although the survivorship of total elbowreplacements has improved in recent times, it is stilla procedure reserved to older patients with low functional

iversity Hospital of Wales, audit department- Ref: 4293.

uests: Narayana Prasad, 5 Lovage close, Pontprennau

SB.

ss: nporth@yahoo.com (N. Prasad).

/$36.00 - see front matter � 2010 Journal of Shoulder and Elbo

.2009.09.016

demand. Aseptic loosening, and hence failure requiringrevision, seems to be the main concern in the use of totalelbow prosthesis.

The implants used for total elbow replacement can dedivided into 3 types: constrained, semi-constrained, andunconstrained. They can also be divided into linked andunlinked prosthesis. Comparison of performance ofcommonly used implants in rheumatoid elbows based onthe results published from individual designer series isdifficult because of heterogeneity of the samples, experi-ence of the surgeons, and manufactures bias. A prospectiverandomized controlled trial would be ideal to compare theperformance of implants, but involves a lot of practicaldifficulty in individual clinical settings.

w Surgery Board of Trustees.

Table I Clinical results of elbow replacement in our series

Souter(n ¼ 44 in 40)

Coonrad-Morrey(n ¼ 55 in 51)

Male:Female 8:32 17:34Mean age (range) years 60 (32-82) 62 (37-81)Mean follow-up

(range) months108 (24-162) 60 (9-118)

Mean final ROM 32.9 to 130degrees

32.6 to 124.3

Mean (median) MEPS 86.8 (85) 80.9 (85)

Total elbow replacement in rheumatoid elbows 377

Souter-strathclyde total elbow prosthesis (StrykerHowmedica,UK) is an unlinked implant that is widely used.There is literature evidence from independent centers onthe long-term follow-up results of this prosthesis when usedfor rheumatoid elbows.3, 6, 10, 19, 20 Coonrad-Morreyprosthesis (Zimmer,Warsaw, IN) is a semi-linked prosthesiswith long-term published results when used for rheumatoidelbows11, 13 and distal humeral fractures.4, 14, 16

The senior author has been performing total elbowreplacements from 1993, and these patients were also beingfollowed up. The indications are rheumatoid arthritis, acutefractures, and post-traumatic arthritis. The initial experiencehas been with unlinked Souter-Strathclyde elbow prosthesis(1993-2000). The senior author subsequently switched hispractice to semi-linked Coonrad-Morrey prosthesis in 1997and this is still ongoing. The outcome of total elbowreplacement for distal humeral fracture in elderly usingCoonrad-Morrey prosthesis has been already published fromour center.14 We decided to analyse long-term clinical andradiological results of Souter (un-linked) and Coonrad-Morrey (semi-linked) TER in rheumatoid elbow.

Patients and methods

The junior author performed a clinical and radiological review ofall the patients who had total elbow replacement, and prepareda database. Patients were reviewed in clinic and scored usingMayo Elbow Performance Score (MEPS)12 by the junior author. Areview of preoperative, immediate postoperative, and final radio-graphs nearest to the final clinical follow-up was also carried out.A review of cases notes was performed in each patient afterclinical and radiological scoring.

The scoring of preoperative radiographs was done using thecriteria described by Morrey and Adams.11 The immediate post-operative radiographs were reviewed for the adequacy ofcementing technique and were graded as adequate, marginal, orinadequate using a described scoring system.16 The final follow-up radiograph was reviewed for the signs of aseptic loosening andgraded between 0 and 4 as described from Mayo clinic.16

Souter

We had performed 44 primary total elbow replacement usingSouter-Strathclyde total elbow prosthesis in 40 patients between1993 and 2000 (Table I). The left to right ratio was 17:27. Sevenpatients had died by the time of final review, so the last availabledata were used for analysis. Of these 7, 1 patient died the nextpostoperative day due to pulmonary embolism, and was, therefore,excluded from the analysis of data to avoid skewing of the results.Three patients (4 elbows) could not attend final clinical review;telephonic questions on pain and activities of daily living were,therefore, carried out on them and last available information fromcase notes were used for analysis. The MEPS clinical scores of6 patients (7 elbows) who had revision of the primary total elbowreplacement and 1 patient who had removal of prosthesis due tolate infection were excluded from the final analysis of meanMEPS score.

Coonrad-Morrey

We included the first 55 Coonrad-Morrey total elbow replace-ments, in 51 patients, for this study (Table I). The left to right ratiowas 26:29. Four patients (6 elbows) could not come for finalreview, telephonic questions on pain and activities of daily livingwere, therefore, carried out on them and last available informationfrom case notes were used for analysis. Four patients had died atthe time of final follow up.

Statistical analysis

The improvement in ROM after TER was compared withpreoperative ROM using paired t test. The survivorship wasanalyzed using Kaplan Meier survivor analysis,5 and theresults were compared using log-rank test. All statisticalanalysis was performed using STATISTICA (version 6.1;StatSoft, Tulsa, OK).

Results

Clinical outcome-Souter

The mean follow-up of all 43 patients, excluding the patientwho died on the first postoperative day, was 108 (range,24-162) months. Forty elbows had more than 5 yearsfollow-up. The follow-up periods for the other 6 patientswho died were, respectively, 24, 46, 48, 53, 63, and 135months. The mean preoperative range of movement wasfrom 31.8� degree of flexion to further flexion of 97.1�. Thesame during final follow-up was 32.9�-130�. Theimprovement in flexion shows statistical significance witha paired t test (P ¼ .001). The mean (median) MEPS was86.8(85) (Table I). Nine elbows had excellent results (scoreabove 90), 13 elbows had good results (score between 75and 89), and 3 elbows had fair results (score 60-74), whilenone of the elbows had poor results. The mean visualanalogue score for the pain at the time of final review was0.6 compared to pre-op value of 8.5.

Radiological review-Souter

The review of immediate postoperative radiographs showedadequate cementing in all 44 elbows. The mean

Table II Location, type, and number of loosening in our series

Souter Coonrad-Morrey

Type 1 (at risk) 8 humerus, 1 ulna, 1 humerus and ulna 2 humerus, 2 ulnaType 2 (at risk) 2 humerus, 2 humerus and ulna 1 humerus,1 ulna, 1 humerus and ulnaType 3 (loose implant) 2 humerus,1 humerus and ulnaType 4 (loose implant) 4 humerus, 2 humerus and ulna

Table III Complication following total elbow replacement in our series

Complications Souter (n ¼ 44) Coonrad-Morrey (n ¼ 55)

Aseptic loosening (types 3 and 4) 8 0Instability 4Periprosthetic fracture 1 (humerus-delayed)Intraoperative fracture 0 1 epicondyle of humerus, 2 ulna crackNerve palsy 2 (1 ulnar and 1 PIN) 2 ulnarChronic regional pain syndrome 0 1Infection 1 (late) 1 (late)Stiffness 0 3 (1 heterotropic ossification)

378 N. Prasad, C. Dent

radiological follow-up in the 43 elbows was 104 months(range, 24-162). The final radiographs showed no evidenceof loosening in 22 of them. We found type 1 radiolucentline in 9 elbows and type 2 in 4. These can be considered atrisk rather than loose implants. We found type 3 looseningin 2 elbows and type 4 in 6, and these can be considered asloose implants. The individual results in humerus and ulnaare as in Table II.

Complications-Souter

Aseptic loosening of types 3 and 4 were found in 8 elbows outof 43 (Table III). Four of the 6 patients with type 4 looseninghad revision surgery, and the remaining 2 refused to haverevision surgery because of personal reasons. The revisionsurgery was performed in these 4 elbows (3 patients) at,respectively, 48, 48, 64, and 96 months follow-up. All6 patients had loosening of the humeral component. Addi-tionally, 2 of them had type 4 loosening of the ulna component.

Instability was a problem in 4 elbows, which includes1 patient with chronic dislocation. Two elbows had revisionbecause of instability, which was performed at 24 and 75months follow-up. The patient with chronic dislocationrefused any further intervention, because he did not have anysymptoms and he had MEPS of 90 and VAS of 2. The otherpatient with instability who refused revision is one of the2 patients with type 4 loosening. The mean follow-up of these6 patients who underwent revision surgery was 60 months.

One patient presented with a fracture of the shaft ofhumerus above the humeral prosthesis following a fall at105 months follow-up. This patient had a revision surgery.

One patient presented with late deep infection at 75months follow-up and ended up with removal of theimplant.

One patient had postoperative ulnar nerve palsy andrecovered completely. Another patient with preoperativeulnar nerve palsy did not show any recovery even aftersurgery. One patient had postoperative posterior interosseusnerve palsy and she died at 46 months follow-up. She hadshown partial recovery at 36 month follow up.

Survivorship analysis-Souter

Kaplan-Meier survivorship analysis5 showed 82.3%survival at 13.5 years considering revision/removal ofimplant as end point (Figure 1). Considering patients whowere offered revision due to type 4 loosening and the onewith chronic dislocation as failures, the survivorship was76% at 10 years.

Comparison of Standard with long stem humeralcomponent in Souter

Of the 44 elbows, 32 had standard humeral component.Three elbows were revised due to type 4 loosening and1 patient with type 4 loosening refused revision. Onepatient had revision for late fracture and another hadremoval of implant for late infection. One patient had mildinstability which did not require revision surgery.

We had 12 patients with long stem humerus of which2 patients underwent revision surgery for instability and1 for type 4 loosening. One patient with type 4 looseningand instability refused revision surgery.

Clinical outcome-Coonrad-Morrey

The mean follow-up of 55 elbows in 51 patients was 60months (range 9-118) (Table I). The minimum follow-up

groupcs

endpoint

0 50 100 150 200

100

95

90

85

80

75

70

Time

)%( ytilibaborp lavivruS

Figure 1 Kaplan-Meier survival analysis with 95% CI for totalelbow prosthesis in our series. ‘s’ for Souter and ‘c’ for Coonrad-Morrey prosthesis. X axis shows time in months. Y axis is thesurvival percentage.

Total elbow replacement in rheumatoid elbows 379

for the surviving patients was 30 months. Among the4 patients who died, the follow-up was 9, 21, 51, and 55months, respectively. The mean preoperative range ofmovement was from 46� of fixed flexion to further flexionof 98.5�. The same during final follow-up was 32.6 to124.3�. The improvement in flexion shows statisticalsignificance with a paired t test (P ¼ .001). The mean(median) MEPS was 80.9 (85). Twenty-one elbows hadexcellent results (score above 90), 12 had good results(score between 75 and 89), 10 had fair results (score60-74), and 2 had poor results (score less than 60). Themean visual analogue score for the pain at the time of finalreview was 1.6 compared to pre-op value of 8.6.

Radiological review-Coonrad-Morrey

The review of immediate postoperative radiographs showedadequate cementing in 48 elbows. The cementing wasmarginal in 2 and inadequate in 5 elbows. The reason forinadequate cementing was the cement not extendingbeyond the tip of either the ulna or the humeral prosthesis.The mean radiological follow-up in the 55 elbows was 56months (range, 6-112). The final showed no evidence ofloosening in 45 of them. We found type 1 radiolucent linein 5 elbows and type 2 in 3. There was no type 3 or4 loosening. The individual results in humerus and ulna areas in Table II.

Complications-Coonrad-Morrey (Table III)

We had a case of intraoperative notching of humerus withepicondylar fracture. This patient at 95 months follow-uphad MEPS of 80, and there was type 1 radiological

loosening of humerus. We had 2 patients with intra-operative ulnar crack and both of them were treated withplaster of paris cast for 6 weeks. These patients had MEPSof 95 at 49 months and 75 at 44 months follow-up,respectively, with no signs of loosening. The latter hadpreoperative ulnar nerve palsy, which did not showrecovery at the time of final follow-up.

Two patients had postoperative ulnar nerve palsy, one ofwhich showed partial recovery at 36 months follow-up, andthe MEPS was 95. The other patient did not show anyrecovery at 62 months and was also suffering from chronicregional pain syndrome, and the MEPS was 55.

There were 3 patients with decreased range of move-ment. The first patient had heterotopic ossification, causingstiff elbow. The MEPS was 90 with no signs of loosening at54 month follow-up. The second patient had bone blockextension of 60�. This is the longest surviving Coonrad-Morrey prosthesis in our series. The MEPS was 95 at 118months follow-up with no signs of loosening. The thirdpatient had stiff elbow with no bone block. This patient’selbow was fixed in 90� flexion preoperatively underwentopen adhesiolysis at 36-months follow-up, which improvedthe ROM slightly. At 78 months follow-up, the ROM was80�-120� with MEPS of 35.

We had 1 case of late deep infection in a severelyrheumatoid patient with multiple co-morbidities. He wastreated by chronic antibiotic suppressive therapy, as herefused any surgical intervention. There was no incidenceof revision in our series. Aseptic loosening was limited totype 2 in 3 elbows and type 1 in 5.

Survivorship analysis-Coonrad-Morrey

Kaplan-Meier survivorship analysis5 showed 100% survivalat mean follow-up of 60 months, considering revision/removal of implant, type 3 or 4 loosening as end points(Figure 1).

Discussion

We have presented the data for 2 consecutive cohorts ofpatients who underwent total elbow replacement under thecare of the senior author for end-stage inflammatory jointdisease using Souter-Strathclyde (unlinked) prosthesis andCoonrad-Moorey (linked) prosthesis. The mean follow-upis obviously more (108 months vs 60 months) in the Souterprosthesis group, because the senior author was using theminitially and later changed his practice to Coonrad-Mooreyprosthesis. The reason for change of practice was increasedincidence of instability and loosening of the Souter pros-thesis. The cohort of patients who had these surgeries isfrom a different time period, but all had the same diagnosis.The mean (SD) pre-operative ROM in the cohort of patientswho had a Souter elbow replacement was 65.4 (24) degrees

380 N. Prasad, C. Dent

compared to 52.8 (34) degrees in the Coonrad-Morreygroup. Although there is an obvious decreased preoperativeROM in the Coonrad-Morrey group, this is not statisticallysignificant (P ¼ .24).

We have no intention to make a direct comparison of theseprosthesis, but we would like to discuss some of the issues inrelation to the loosening and failure of the prosthesis. Themain weakness of our paper is the difference in follow-up;however, the homogeneity of the sample as a result of samediagnosis and same surgeon performing the procedure addsto its strength. The comparison of Kaplan-Meier survivalanalysis in our series showed a statistically significantdifference between 2 groups (P ¼ .03, Log-Rank test)(Figure 1). When we compare the survival of the implants at5 years, we find that the Coonrad-Morrey prosthesis has100% survival compared to a survival of 92.9% for the Souterprosthesis. In the Souter group, before the 5-year period,3 revisions were performed. One was for instability at 24months and 2 for aseptic loosening at 48 months each. Thefunctional outcome in the form of MEPS and improvement inrange of movement does not show any difference between2 cohorts. We did not want to make a comparison of thefunctional outcome purely because of the discrepancy in thefollow-up. However, in looking at the survival at 5 years, itclearly shows that the Coonrad-Morrey prosthesis hasperformed better than the Souter prosthesis.

Souter-Strathclyde prosthesis

In our series of Souter elbow replacement, 40 of the 44elbows have more than 5 years follow-up. We have foundan improvement in elbow flexion by 42.1� compared topreoperative status; but, there was no improvement inthe extension, which is consistent with the literatureevidence.6, 10, 19, 20 In patients who were clinicallyreviewed, when we considered patients who have surviveda revision surgery the percentage of excellent to goodresults according to MEPS are 88% at a range of follow-upfrom 66 to162 months. When we include as poor results the7 elbows that had revision surgery and the 1 that wasremoved because of infection, then the percentage ofexcellent to good results drops to 66.7%. The revision ratein our series was 18.2%, including implant removal forinfection, with 82.3% survival at 13.5 years. When we alsoconsidered patients with loosening and instability whorefused to have revision surgery as failures, our survivalfigures dropped to 76% at 10 years, which is very muchconsistent with the published literature evidence.6, 10, 19, 20

The subjective satisfaction rate among patients who arecurrently alive was 100%, including patients who hadrevision and implant removal.

The results of 186 Souter elbow replacements publishedfrom Wrightington hospital by Trial et al in 1999 showed87% survival at 12 years.19 The survival rate for Souterelbow prosthesis was noted to be 85% at 10 years by

Ikavalko et al from Finland in 2002.3 They have a bigseries of 525 patients and had to carry out 33 revisionprocedures for aseptic loosening, 30 additional proceduresfor instability, and 14 procedures for infection of which 12were deep.

In 2004, Van der Lugt et al published their result of 77%survival for Souter prosthesis at 10 years, consideringrevision as the end point.20 They noticed a complicationrate of 29.1% in their series of 204 elbows. They alsoreported a dislocation rate of 3.4%. A study by Malone etal10 (2004) showing 74% survival at 10 years and that byKhatri et al6 (2005) showing 75% survival at 9 years(including 3 deep infection) with 6.3% instability rates arestudies like ours with identical results.

The radiographic analysis by Trail et al in 1999 identi-fied the mode of failure specifically as a tilting of thehumeral component.19 The proximal tip of humeralcomponent undergoes ventral migration, as the humeralcomponent moves to an extended position in relation to thedistal humerus. The ventral migration of the short stemhumeral component was noticed by Malone et al in theirseries of 68 elbows.10

We have also noticed ventral migration of the humeralcomponent in 8 of the elbows with types 3 and 4 loosening(Figure 2). The reason for the anterior tilting of the shortstem humeral component is not known. It is believed to bedue to forces transmitted through the humeral componentduring flexion and extension of the elbow. This has led tothe use of long stem humeral component for all of the casesby some of the surgeons.

Trail et al18 compared the outcome between standardand long stem humeral component. The incidence ofloosening of the long stem humeral component was lessthan half of the standard component. They noticed,however, instability problems requiring revision for longstem component. This is because the insertion of long stemcomponent requires bigger exposure and releases. In ourseries, we had 2 cases of instability that required revisionsurgery out of 12 long stem prostheses (Figure 3). Therewas no significant difference in cumulative survival rate ofthe Souter elbow, comparing standard and long stemprosthesis in the Wrightington.18

The standard use of long stem humeral components forprimary Souter total elbow replacement has been ques-tioned by some of the authors.10 The argument put forwardby this group is that use of long stemmed humerus mayprevent a small number of elbows from failing by ventralmigration, but could complicate revision surgery withlonger stemmed prosthesis needed for proximal fixation. Inour series, too, we have gross loosening of 2 long-stemmedhumeral components: 1 at 48 months, which was revised,and the other at 146 months refused revision.

The loosening of ulnar component is moderate. Thecomparison from Wrightington has shown statisticallyincreased ulnar loosening in long stem humeral groupcompared to standard humeral component group.18 This is

Figure 2 Loosening of the humeral component in Souter due toventral migration of the tip of the humeral stem.

Figure 3 Instability in Souter prosthesis showing chronicdislocation.

Total elbow replacement in rheumatoid elbows 381

moderate and has not increased the revision rate. They haveidentified a subgroup of patients who had snapfit ulnarcomponent which, when compared to standard ulnarcomponent, had highly significant loosening requiringrevision.18 We have no experience with snapfit ulnarcomponent. The explanation in literature for this looseningis mild internal rotation of the ulnar shaft during insertionof prosthesis. This malpositioning along with highlycongruent articulation may cause loosening.17

We did not find any literary evidence of significantpolyethylene wear as a cause of failure requiring revisionassociated with Souter elbow prosthesis. This, too, has beenour experience.

Coonrad-Morrey prosthesis

Our series of Coonrad-Morrey prosthesis on rheumatoidelbow includes our first 51 patients with a minimum follow-up of 30 months and mean follow-up of 60 months. Thepostoperative improvement in extension was 13.4� comparedto improvement in flexion of 25.8� at the time of final follow-up. Fifty-one out of 55 elbows were pain free or only mildlypainful. Thirty-three of 45 patients with full MEPS showedgood or excellent results (73.3%). We did not have anyaseptic loosening (types 3 and 4) excluding types 1 and

2 radiolucency (Figure 4) and the overall complications were9 out of 55 (16.4%). There were no patients with elbowinstability. The survival rate of prosthesis taking revision asend point was 100% and the subjective satisfaction rate was98% (1 patient not satisfied).

The long-term follow up results of Coonrad-Morreyprosthesis for rheumatoid arthritis from designer surgeonsof the Mayo Clinic shows a survival rate of 94.4% at5 years and 92.4% at 10 years.2 This series also showedgood pain relief, significant improvement of range ofmotion, and none of the patients had any objective orsubjective instability. The complication rate is 14% with13% re-operation rate.

The published literature on the outcome of CoonradMorrey prosthesis from independent centers is limited tothe use of this prosthesis for distal humeral fractures, andthis includes one of our previous publications.14 Acomparative study from Oxford looks at Coonrad-Morreyprosthesis for rheumatoid elbow from the perspective of anindependent center.9 According to this paper, the 5-yearsurvival rate considering revision and radiographic signs ofloosening as end points are 90% and 86%, respectively.

The longest follow-up study is from the designers’ ownseries, and it consists of 78 elbows with a follow-up of 10-15years.2 They had only 2 revisions for aseptic loosening, ofwhich one had an uncemented elbow replacement to beginwith. The second patient had loosening of ulna component.They have also reported fracture of ulna component in 1patient and olecranon in another. The comparative study byLittle et al9 from Oxford showed only 1 case of asepticloosening among Coonrad-Morrey group. They noted ulna

Figure 4 Type 2 loosening of humeral and ulnar component inCoonrad-Morrey prosthesis.

382 N. Prasad, C. Dent

osteolysis in 4 elbows (16%) which were occult initially, ofwhich 2 of them progressed to frank loosening. The versionof Coonrad-Morrey implant used during this study hadmethylmethacrylate coating over the ulnar stem and there isconcern raised over methylmethacrylate precoat andosteolysis.4 They noted better survival rate for Coonrad-Morrey prosthesis compared to Souter and Kudo prosthesis.9

Dislocation, as expected, was not a problem with Coonrad-Morrey prosthesis and revision, because aseptic looseningwas also less frequent.18

A recent paper from the Mayo Clinic has tried to addressthe issue of ulna component loosening in Coonrad-Morreyprosthesis.1 They reviewed 10 patients who had painfulpistoning of the polymethylmethacrylate-coated ulnarcomponent of Coonrad-Morrey total elbow prosthesis. All10 elbows were found to be loose during revision surgery.Distraction force of ulnar component occurs when elbow isflexed past a limit set by any impinging structure anteriorly.To prevent this problem following any total elbow arthro-plasty, they have recommended that the surgeon shouldcheck for anterior impingement intraoperatively.1 Thiscondition also can be avoided by ensuring that the ulnacomponent is not inserted too far distally.1

Literature data on polyethylene wear after elbow arthro-plasty is limited. Polyethylene wear was not an issue with theprevious elbow prosthesis, because the loosening and

implant dislocation of the elbow prosthesis tend to occurbefore this. The results of Coonrad-Morrey prosthesis fromthe designers’ own series show 1.4% poly wear in rheumatoidarthritis series compared to 2.4% in post-traumatic arthritis.7

The time period between the index arthroplasty and thebushing exchange had a mean of 7.9 years in the whole seriesof 919 patients. The poly wear is detected by using an APradiograph done in full extension, which shows asymmetrybetween articulating portion of the ulnar component and themedial or lateral aspect of the humeral articulating yoke. Inour experience, most of the elbows did not have full extensionafter surgery. As this has been the same experience univer-sally, we are little circumspect about this technique ofdetecting poly wear from plain radiographs.

Osteolysis that developed following poly wear was notfound to be extensive in any of the cases from the MayoClinic series. This seems to be because of smaller volumeof poly compared to hip and knee replacements. We haveno experience with poly wear an osteolysis this is probablydue to shorter follow up.

Conclusion

We find satisfactory pain relief and functional results atlong-term follow-up of a Souter (un-linked) elbowarthroplasty for rheumatoid arthritis. However, ourresults and literature review shows that high revision ratefor aseptic loosening and instability are matters ofconcern. Our mid-term results with Coonrad-Morreyshows satisfactory functional results with no evidence ofloosening or instability. The literature evidence on thisprosthesis for rheumatoid arthritis is predominantly fromthe designers’ own series and is showing excellentresults at long term with low rate of aseptic loosening.However, long-term results from independent centres areneeded to set up a bench mark on the performance ofCoonrad-Morrey prosthesis. The mode of failure can beunderstood on the basis of difference in the biome-chanics of different types of implant designs. Thequality of bone and soft tissues in rheumatoid arthritis isan important factor when we consider any design type ofelbow prosthesis and further research in tissue engi-neering may help us to solve this which would help thelong term survival of elbow prosthesis.

Disclaimer

The authors, their immediate families, and any researchfoundations with which they are affiliated have notreceived any financial payments or other benefits fromany commercial entity related to the subject of thisarticle.

Total elbow replacement in rheumatoid elbows 383

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