From the *Plastic Surgery Department, Cleveland Clinic, Cleveland, OHof Bioinformatics and Biostatistics, University of Louisville, LouisvInstitute, Louisville, KY.

Received for publication December 30, 2014; accepted in revised f

L.R.S. designed the Aptis/Scheker implant and is partial owner of

SCIENTIFIC ARTICLE

Functional Outcomes of the Aptis-Scheker Distal

Radioulnar Joint Replacement in Patients

Under 40 Years Old

Antonio Rampazzo, MD, PhD,* Bahar Bassiri Gharb, MD, PhD,* Guy Brock, PhD,†Luis R. Scheker, MD‡

Purpose To study the functional results after Aptis-Scheker distal radioulnar joint (DRUJ)replacement in young patients.

Methods We performed a retrospective study selecting all patients under age 40 years, with aclinical and radiological follow-up longer than 2 years, who underwent DRUJ replacement.Patients’ charts were reviewed and age at surgery, profession, hobbies, comorbidities, diag-nosis, previous procedures, and complications were recorded. Preoperative and postoperativeDisabilities of Arm, Shoulder, and Hand and Patient-Rated Wrist Evaluation scores, visualanalog scale score, grip strength, lifting capacity, and wrist range of motion were recorded.Functional results and characteristics of the patients were correlated with linear regression. AKaplan-Meier curve was plotted.

Results We performed 46 arthroplasties. Average patient age was 32 years. Forty-one arthro-plasties were performed for pain and 5 for pain and instability. Average follow-up was61 months. Thirty-seven patients underwent multiple procedures before DRUJ replacement(1.7 � 1.2 procedures). Extensor carpi ulnaris release with implant coverage using a localadipofascial flap (5) or dermal-fat graft (4) was the most common procedure performed afterimplantation of the prosthesis. Thirty surgeries were undertaken to address complications afterDRUJ replacement in 15 wrists. A total of 36 procedures not related to DRUJ replacement wereperformed in 15 wrists after the arthroplasty. Grip, lifting, Disabilities of Arm, Shoulder, andHand and Patient-Rated Wrist Evaluation scores, visual analog scale score, and supinationshowed statistically significant improvement after surgery. Functional results were comparablein patients who received the implant with either a standard or extended stem. Patient age andnumber of the previous procedures did not correlate with functional results. The 5-year survivalof the implant was 96%.

Conclusions In this group of young patients, the implant improved the functional status of theextremity. The most frequent complication was extensor carpi ulnaris tendonitis, which wasaddressed by interposition of an adipofascial flap. (J Hand Surg Am. 2015;40(7):1397e1403.Copyright � 2015 by the American Society for Surgery of the Hand. All rights reserved.)

Type of study/level of evidence Therapeutic IV.Key words Arthritis, distal radioulnar joint, implant, prosthesis, replacement.

; and the †Departmentille; and the ‡Kleinert

orm April 22, 2015.

Aptis Medical.

Corresponding author: Luis R. Scheker, MD, Christine M. Kleinert Institute, 225Abraham Flexner Way, Suite 850, Louisville, KY 40202; e-mail: lscheker@kleinertkutz.com.

0363-5023/15/4007-0017$36.00/0http://dx.doi.org/10.1016/j.jhsa.2015.04.028

� 2015 ASSH r Published by Elsevier, Inc. All rights reserved. r 1397

FIGURE 1: The Aptis-Scheker implant is composed of a cobaltchromium ulnar stem that has the distal third covered with a ti-tanium plasma spray, an ultrahigh-molecular-weight polyethyleneball, and a radius plate with a cover creating a socket.

TS UNDER 40 YEARS OF AGE

T HE DISTAL RADIOULNAR JOINT (DRUJ) is criticalfor the stability of the wrist and forearm and hasan important load-bearing role in distributing

applied forces from the hand and wrist to the radius andsubsequently to the ulnar head.1 Gordon et al2 showedthat changes in joint kinematics as a result of ulnar headexcision may lead to altered loading on the adjacentjoints, muscles, and soft tissue structures. Numeroussurgical procedures have been used for the managementofDRUJarthritis, ranging fromdistal ulna excision3,4 andhemiresection-interposition arthroplasty5 to arthrodesisof the DRUJ with a distal ulnar osteotomy.6,7 However,these techniques do not restore the normal jointanatomy and kinematics and thus can lead to persistentpain8 and impaired function with radioulnar impinge-ment and instability of the radius,9 whichmay bemuchmore symptomatic in active patients. To address theseproblems, many ulnar head implants have been created,such as the Swanson silicone ulna head,10 the Herbertceramic head,11 and the Avanta implant.12 These hemi-arthroplasties replace the ulnar head alone anddependonan intact sigmoid notch and reconstructable triangularfibrocartilage ligaments to provide stability to the joint.Although patients demonstrated improvement in pain,pronation, supination, and grip strength,12,13 long-termresults have been unpredictable,13,14 with an increasedincidence of failure compared with bipolar implants.12

Total DRUJ prostheses, including the Aptis-Schekerprosthesis (Aptis Medical, Louisville, KY),15e17 theAlkmaar prosthesis,18 and the Schuurman implant,19

address sigmoid notch abnormalities and the absenceof DRUJ soft tissue stabilizers. The Aptis-Scheker totalDRUJ replacement has been used since 2005 with goodresults in patients with arthritis of the DRUJ or previousexcision arthroplasties.20e24 Although DRUJ replace-ment was originally intended for elderly, low-demandpatients, trends in contemporary practice indicate thatan increasing number of procedures are being performedin younger patients with osteoarthritis of the DRUJ. Inthis study we analyzed the functional outcomes afterDRUJ replacement with the Aptis-Scheker prosthesis inyoung patients.

1398 APTIS IMPLANT IN PATIEN

MATERIALS AND METHODSWe performed an institutional review boardeapprovedretrospective study to analyze the outcomes of DRUJreplacement with an Aptis-Scheker implant (Fig. 1)21 inpatients aged under 40 years who underwent thearthroplasty between 2005 and 2011, with a minimum2-year radiological and clinical follow-up. Patientswereidentified using a prospectively maintained database.Patients aged 40 years and older or aged less than 40

J Hand Surg Am. r V

years with a clinical or radiological follow-up shorterthan 2 years were excluded from the study.

Patients’ demographic data including job and hobbies,diagnosis, previous surgeries, implant surgery, post-operative procedures, complications, and satisfactionwere reviewed. Pain level was assessed with a visualanalog scale (VAS) and graded between 0 and 10.17

Preoperative and postoperative Disabilities of the Arm,Shoulder, and Hand25 (DASH ) and Patient-Rated WristEvaluation26 (PRWE) scores were calculated. Werecorded grip strength using a Jamar Hydraulic HandDynamometer (Asimov Engineering Company, LosAngeles,CA) inposition2 (4cm).Rangeofmotionof thewrist and forearm was measured according to AmericanMedical Association guidelines.27 We evaluated liftingcapacity with the patient standing and with the shoulder,elbow, and wrist in neutral position by lifting differentweights of 2, 4, 6, and 8 kg beginning with the elbows inextension and raising the weight to the horizontal plane(elbows at 90� flexion). Only the extremity under eval-uation was assessed while the other was resting. At finalfollow-up, patients were asked whether they were satis-fied after DRUJ replacement arthroplasty (yes or no)and whether they would advise patients with the samepathology to undergo the procedure (yes or no). Thefellows collected the data and the study nurse practitionerobserved all of the patients. Three authors (A.R., B.B.G.,and G.B.) who were not involved in the original surgeryindependently reviewed the x-rays. Radiographic vari-ables included the anatomic shape of the sigmoid notchand ulnar variance.28,29 The articular surface at the sig-moid notch was classified according to the Tolat classi-fication.29 Radiographic evidence of DRUJ subluxationwas derived from the true lateral radiographs.30 Longi-tudinal lines were drawn through the centers of the radiusand ulnar head and the distance between the 2 lines at thedistal-most aspect of the sigmoid notch wasmeasured. A

ol. 40, July 2015

FIGURE 2: The ulnar-based adipofascial flap is marked. Dissec-tion starts on the radial side and ends with exposure of the ulnarhead.

FIGURE 3: The adipofascial flap is completely elevated and theECU tendon sheath is released. The ulnar head has beenremoved, the radial plate has been positioned, and the ulnar stemis ready to be inserted.

FIGURE 4: The adipofascial flap has been passed under the ECUtendon and sutured radially to cover the implant completely.

APTIS IMPLANT IN PATIENTS UNDER 40 YEARS OF AGE 1399

positive difference of greater than 5mmwas defined as asign of dorsal implant instability and a negative mea-surement greater than 5 mm was defined as volar insta-bility.12 We used the immediate postoperative films andthe most recent x-rays to assess for any change in insta-bility value, signs of implant loosening (more than 2 mmlucency around the stem), screw loosening and malpo-sition, osteolysis under the ulnar head collar, and pedestalformation at the tip of the stem. Implant survival wasdefined asmaintenance of the original arthroplasty.Ulnartranslocation indices (McMurtry,Chamay,DiBenedetto,Schuind, and Bouman) were calculated.31 Radial platemalpositionwasassessedon lateral x-rays andconsidereddisplaced if the margin of the plate was 2 mm off themargin of the radius. In the Scheker test, the wrist isstress-loaded by asking the patient to hold a 2.2-kg leadcylinder with the shoulder adducted, the elbow flexed to

J Hand Surg Am. r V

90�, and the forearm in the position of neutral rotation.The radiograph is taken with the beam aligned in thecoronal plane with respect to the anatomical position.During this maneuver the patient is asked whether theaction of lifting the weight recreates the pain. The pa-tient’s response is then correlated with the radiographicfindings. We performed this test preoperatively to assessfor ulna impingement on the radius in patients who hadreceived previous salvage procedure.32

In the last 37 patients, we changed our procedure toprevent extensor carpi ulnaris (ECU) irritation byraising an ulnar-based adipofascial flap to cover theimplant. Skin and subcutaneous fat were elevated fromthe forearm fascia up to the second dorsal compart-ment. An adipofascial-retinacular flap with an ulnarbase and extending radially to the second compartmentwas elevated to later provide a barrier between theprosthesis and the ECU tendon33 (Figs. 2e4).

Differences in preoperative and postoperative gripstrength, lifting capacity, DASH and PRWE scores,VAS, flexion, extension, pronation, supination, radialand ulnar deviation of the wrist, and ulnar translocationindices were compared using paired Student t tests. Weused the same test to compare differences in DASH andPRWE scores, VAS, grip strength, supination, prona-tion, and use of standard or extended stem, previoussalvage procedures performed, and work type. Studentt test was used to compare age and number of previousprocedures in patientswhodevelopedor did not developECU tendonitis. Extensor carpi ulnaris tendonitis wasdiagnosed clinically by asking the patient whether therewas pain with extension and ulnar deviation of thewrist; it was confirmed if pain subsided after injection of0.5mL triamcinolone (10mg/1mL)mixedwith 0.5mLlidocaine 1% into the ECU sheath. Fisher exact test wasused to assesswhether the prevalence of ECU tendonitis

ol. 40, July 2015

TABLE 1. Procedures Performed BeforeReplacement of DRUJ With Aptis-Scheker Implant

PreoperativeProcedure Wrists, n (%)

Treatment distalradius fracture

22 of 46 (48%)

Open reduction internal fixation 14

Casting 3

Closed reduction percutaneous pinning 2

Correction malunion (open wedge 3

1400 APTIS IMPLANT IN PATIENTS UNDER 40 YEARS OF AGE

was different in patients who did or did not havecoverage of the implant with a local adipofascial flap, ifthey were manual workers or had a desk job, or if theyunderwent or did not undergo salvage procedures beforereplacement of the joint. A linear regression test wasused to see whether there was a correlation betweenoutcomes and the number of previous surgeries, post-operative procedures, and patient age. All tests were2-sided;P< .05was considered statistically significant.A Kaplan-Meier curve was plotted to visualize implantfailures over time.

osteotomy and iliac crest bone graft)

Ulna shortening 13 of 46 (28%)

Wrist procedures 11 of 46 (24%)

Total wrist arthrodesis 3

Stabilization of distal ulna stump 2

4-corner arthrodesis 2

Wrist arthroplasty 1

Proximal row carpectomy 1

Lunate grafting 1

Lunotriquetral arthrodesis 1

Distal radioulnarligament reconstruction

8 of 46 (17%)

Darrach procedure 5 of 46 (11%)

Triangular fibrocartilagecomplex repair

4/46

Wrist arthroscopy 3/46

DRUJ arthrotomy 2/46

Sauve-Kapandji procedure 2/46

Wafer procedure 2/46

DRUJ arthroplasty 2/46

Excision osteophytes DRUJ 1/46

Interosseous membrane release 1/46

Radiocapitellar arthroplasty 1/46

Ulna styloid resection 1/46

RESULTSWe excluded 150 patients from the study because theywere aged 40 years or older, and 8 because of short-termfollow-up or incomplete data. Forty-six implants wereperformed in 41 patients (5 bilateral). Average age ofthe patients was 32 years (range, 18e39 y). Averagefollow-upwas 61months (range, 24e99mo). Therewere27 women and 14 men. The DRUJ was replaced in 24dominant and in 22 nondominant wrists. Twenty-sevenpatients were manual workers, 11 had desk jobs, and 3were disabled. Indications for joint replacementwere painin 41 patients and pain and gross instability of the jointunder stress in 5. All patients failed a 6-month period ofconservative treatment, which consisted of activitymodification, gentle physical therapy, nonsteroidal anti-inflammatory drugs, and immobilization. If this regimenwas not effective, 3 steroid injections (as above) weregiven at 6-week intervals into the DRUJ. Failure wasindicatedbypersistenceof pain and functional limitations.

Twelve patients presented with comorbidities: Made-lung deformity (n ¼ 4), Ehlers-Danlos syndrome (n ¼2), connective tissue disease (n¼ 2), post-burn scarring(n¼ 2), stroke (n¼ 1), and cervical radiculopathy (n¼1). In 13 patients we used an extended stem. Ninewristshad a DRUJ replacement without previous procedureson the same joint. Thirty-seven wrists had an average of1.7 � 1.2 procedures (range, 1e7 procedures) per-formed before the replacement (Table 1). The mostcommon procedures performed at the time of replace-ment of theDRUJwere peripheral nerve decompression(n¼ 9), removal of previous fixation plates (n¼ 6), andone of each of the following: posterior interosseousnerve neurectomy, debridement of distal radius dorsallip, interosseous membrane release, and 4-cornerarthrodesis. Twenty-three wrists (50%) had no proce-dure performed after replacement of the DRUJ. Thirtysurgeries were performed for complications after DRUJreplacement in 15 wrists (33% of wrists). Thirty-sixsurgeries were performed in 15 wrists after DRUJreplacement but were not related to complications of the

J Hand Surg Am. r V

implant (33% of wrists). The most common post-operative complication was ECU tendonitis in 9 wrists,which was treated with ECU sheath release andcoverage with a dermal-fat graft (n ¼ 4) or a local adi-pofascial flap (n¼ 5). Two implants were replaced: onepatient fell and fractured the radius and bent the collar ofthe ulnar stem; the other patient had implant removalbecause of infection. An implant was replacedwhen theinfection resolved. Other complications were ectopicbone formation around the ulnar stem (n¼ 3), clickingwith active motion (n ¼ 2), and one instance each ofradial plate malposition, implant failure, and lunate-implant impingement. In 4 patients, osteophytesdeveloped within 2 years after DRUJ replacement andwere removed from the distal ulnar stem. Osteophyte

ol. 40, July 2015

TABLE 2. Further Procedures Performed AfterReplacement of DRUJ Joint

Further Postoperative Procedures(Unrelated to Complications)

UpperExtremities,

n (%)

Peripheral nerve decompression 15 of 46 (33%)

Cubital tunnel release 4

Radial tunnel release 3

Guyon canal release 3

Pronator release 2

Ulnar nerve transposition 2

1

Wrist procedures 8 of 46 (17%)

4-corner arthrodesis 1

Radiolunate arthrodesis with iliaccrest bone graft

1

Radioscapholunate arthrodesis 1

Total wrist arthrodesis 1

Excision lunate 1

Removal radiocarpal joint implant 1

Synovectomy radiocarpal joint 1

Stabilization dorsal capsule 1

Elbow procedures 5 of 46 (11%)

Release for lateral epicondylitis 3

Release for medial epicondylitis 1

Medial collateral ligament repair 1

Tendon transfer or release 2 of 46

Extensor carpi radialis longus toECU transfer

1

Lengthening of flexor carpi radialis,flexor carpi ulnaris, palmarislongus tendon

1

Brachial plexus procedures 2 of 46

Brachial plexus exploration 1

Anterior, middle scalenectomies andfirst rib resection

1

Tenosynovitis release 2 of 46

First dorsal compartment release 1

Trigger finger release 1

Brachioradialis muscle release 1 of 46

Interosseous membrane release 1 of 46

TABLE 3. Paired Student t Test Comparison ofPreoperative and Postoperative Values

Test

Preoperative(Average �

SD)

Postoperative(Average �

SD)P

Value

Grip (kg) 31 � 16 49 � 25 < .001†

Lifting (kg) 10 � 7 17 � 6 .018*

DASH 56 � 22 27 � 27 .008†

PRWE 64 � 22 30 � 30 .002†

VAS 8 � 2 2 � 2 < .001†

Pronation (degrees) 69 � 20 77 � 13 .48

Supination (degrees) 62 � 24 73 � 20 .021*

Extension (degrees) 55 � 16 56 � 24 .28

Flexion (degrees) 53 � 17 56 � 21 .065

Radial deviation(degrees)

17 � 7 21 � 10 .93

Ulnar deviation(degrees)

30 � 6 28 � 12 .23

*Differences are significant.†Differences are highly significant.

APTIS IMPLANT IN PATIENTS UNDER 40 YEARS OF AGE 1401

recurrence was not noted thereafter. Two polyethyleneballs were replaced because of clicking of the jointduring active motion. Other secondary operationsincluded replacement of ulna stem (n ¼ 2), and oneinstance each of posterior interosseous nerve neuromaexcision, radial plate repositioning, and partial lunateexcision. On preoperative x-rays, 10 wrists revealeddorsal instability. The relationship between the radius

J Hand Surg Am. r V

and ulna was: ulna plus (n¼ 15), ulna minus (n ¼ 16),and ulna neutral (n ¼ 8). Seven wrists showedimpingement of the stump of the ulna on the radiusduring lifting. Thirteen wrists were classified as Tolattype 1, 18 as type 2, and 3 as type 3. In 12 wrists it wasimpossible to assess the Tolat class because part of theulnar head was partially or totally missing. Meanradiological follow-up was 48 months (range, 24e70mo). One wrist showed loosening of the implant,osteolysis under the ulnar head collar, and pedestalformation because of infection. The x-ray of one patientdemonstrated a loose screw. This was asymptomaticanddid not require treatment. No implants showedvolaror dorsal instability. The main procedure performedafter DRUJ replacement and not considered a compli-cation of DRUJ replacement was peripheral nervedecompression (Table 2). Grip strength, lifting capacity,DASH and PRWE scores, VAS, and supination statis-tically improved after replacement of the joint (P< .01)(Table 3). There were no statistically significant differ-ences in functional outcomes between patients whoreceived replacement of the DRUJ with a regular orextended ulnar stem implant (P > .05) (Appendix A,available on the Journal’s Web site at www.jhandsurg.org). Linear regression analysis documented no correla-tion between functional outcomes and the number ofprevious surgeries, age of the patients, or number ofpostoperative complications (P > .05) (Appendix B,available on the Journal’s Web site at www.jhandsurg.org). Patients who did not have salvage procedures

ol. 40, July 2015

1402 APTIS IMPLANT IN PATIENTS UNDER 40 YEARS OF AGE

before DRUJ replacement showed a greater reduction inpain comparedwith patients who had salvage procedures(P< .01) (Appendix C, available on the Journal’sWebsite at www.jhandsurg.org). Extensor carpi ulnaristendonitis correlated with the absence of coverage with alocal adipofascial flap (P < .01) (Appendixes D and E,available on the Journal’s Web site at www.jhandsurg.org). There was no evidence of ulnar translocation afterDRUJ replacement (P> .05) (Appendix F, available onthe Journal’s Web site at www.jhandsurg.org). Kaplan-Meier curve showed a 5-year survival of 96% (95%confidence interval, 0.899e1.0). Two patients werenot satisfied after DRUJ replacement and would notadvise patients with the same pathology to undergo theprocedure. Excluding the 3 patients who were disabled,the remaining patients were able to go back to work.Median time to return to work was 2 months, and therewasno statistically significant differencebetweenmanualand desk workers. The lifting limit was set at 8 kg.

DISCUSSIONIn recent years, several authors have demonstrated therole of the ulnar head and its importance for the stabilityof the DRUJ.15,34e36 Loss of the ulnar head disrupts thebiomechanics and load-bearing capacity of the DRUJ.Therefore, in managing a painful DRUJ, every effortshould bemade tomaintain the ulnar head.21 Indicationsfor implant arthroplasty after resection of the ulnar headare principally related to painful instability.34 Althoughmost patients treated with monopolar implants demon-strate an improvement in pain, range of motion, andgrip strength,12,13 long-term results are unpredict-able13,14 and there is an increased incidence of failurecompared with bipolar implants (17% vs 6%).12,21

The implant analyzed in this study is a bipolarimplant that has been on the market since March 2005after Food and Drug Administration approval. The se-nior author (L.R.S.) has replaced 309 distal radioulnarjoints, and overall more than 2,300 implants have beenused worldwide.

Kachooei et al16 recently reportedon13patients,meanage 44 years, who had improvement in wrist range ofmotion and activities of daily livingwith high satisfactionwhen the Aptis-Scheker implant had been placedfor chronic DRUJ pain, instability, and stiffness. Implantsurvival was 100% at a median follow-up of 60 months.

In 17 patients with rheumatoid arthritis, mean age 57years, Galvis et al17 showed an improvement in VAS,pronosupination, andDASHandPRWEscores, and highpatient satisfaction.

These studies confirmed results published in 2008by Laurentin-Perez et al.21 In 31 patients, mean age 46years, pronosupination, grip strength, lifting capacity,

J Hand Surg Am. r V

PRWEandDASH scores, andVAS improved. Axelssonand Sollerman22 reported a significant improvement inDASH scores in 9 patients with an average follow-up of3.7 years.

Based on the encouraging published results19e21,35,36

and our clinical outcomes, our indications for DRUJreplacement were extended to patients under age 40years. Most of these patients had undergone severalprevious procedures before the replacement. Gripstrength, lifting capacity, DASH and PRWE scores,pain, and supination improved significantly after theimplant arthroplasty. The midterm results in theseyounger patients are similar to the results reported byLaurentin-Perez et al21 in older patients.

Schuurman and Teunis19 reported results with adifferent bipolar implant in patients, average age 45years, at 49 months’ follow-up and showed a failureincidence of 38%. Grip strength, forearm pronation,and VAS had meaningful improvements in patientswho retained the prosthesis.

van Schoonhoven et al13,14 reported the outcomes ofHerbertmonopolar implants in 16 patients, average age45 years, at 11 years of follow-up. All cases showedremodeling of the sigmoid fossa and bone resorptionbeneath the collar of the prosthesis. Pain, grip strength,pronation, and supination improved and were stable.Two patients required further surgeries for instability,which contraindicated the use of this implant in pa-tients with insufficient soft tissue stabilizers.

Kakar et al12 published the functional results of theAvanta monopolar implant in 47 patients, average age48 years, at 56 months of follow-up. Thirty percent ofthe patients underwent an additional surgical proce-dure. At 6 years’ follow-up the survival of the implantwas 83%. Extended collar and previous proceduresrepresented risk factors for failure.

In our series, the only difference between patientswho had the replacement immediately after failure ofconservative treatment and those who underwentmultiple surgical procedures before replacement of thejoint was a statistically significant greater reduction ofpain in the former group. Peterson et al37 showed thatmultiple procedures performed on the DRUJ causepoor outcomes after salvage of forearm instability.

The implant used in this study demonstrated goodsurvival in patients with previous excision of the ulnarhead and when soft tissues were insufficient for stabi-lization of the DRUJ. Because ulnar head resectiondisrupts the biomechanics of the DRUJ14,31e33 andresults after salvage procedures often show instabilityand pain,14 we now offer replacement arthroplastyimmediately after failure of conservative treatment topatients with DRUJ arthritis. This was also suggested

ol. 40, July 2015

APTIS IMPLANT IN PATIENTS UNDER 40 YEARS OF AGE 1403

by Willis et al,38 who believed that there can be anindication for primary replacement in patients witharthritic change of the DRUJ.

The main complication of the procedure in ourgroup of 46wristswasECU tendonitis, which occurredin 19% of the wrists. We encountered ECU tendonitisonly when the adipofascial flap had not been used. Thetendonitis may have been caused by direct contact withthe implant and may be avoided by dissecting a localadipofascial flap at the beginning of the surgery tocover the implant. Younger age or increased manualactivity did not increase the risk of ECU tendonitis.

Two implants had to be removed and replaced.Excluding the patient who developed infection, pa-tients did not develop lucency around the implant orinstability. This problem occurs frequently with theuse of other implants.13 Kakar et al12 reported a 17%failure incidence in their group of 46 patients.

One limitation of the current study is the follow-up.Although the average follow-up was 6 years, we stillneed to observe these patients because they are youngand could still develop complications. A second limi-tation is that several surgeries were performed that wereunrelated to complications afterDRUJ replacement, andthesemight have contributed to the improvement shownbyDASH,PRWE, andVASscores at the last follow-up.

REFERENCES

1. Shaaban H, Giakas G, Bolton M, Williams R, Scheker LR, Lees VC.The distal radioulnar joint as a load-bearing mechanism—a biome-chanical study. J Hand Surg Am. 2004;29(1):85e95.

2. Gordon KD, Dunning CE, Johnson JA, King GJ. Kinematics of ulnarhead arthroplasty. J Hand Surg Br. 2003;28(6):551e558.

3. DarrachW. Partial excision of lower shaft of ulna for deformity followingColles’s fracture. 1913. Clin Orthop Relat Res. 1992;(275):3e4.

4. Darrach W. Partial excision of lower shaft of the ulna for deformityfollowing Colles’ fracture. Ann Surg. 1913;57:53e57.

5. Glowacki KA. Hemiresection arthroplasty of the distal radioulnarjoint. Hand Clin. 2005;21(4):591e601.

6. Kapandji IA. The Kapandji-Sauvé operation: its techniques and indica-tions in non rheumatoid diseases. Ann Chir Main. 1986;5(3):181e193.

7. Sauvé L, Kapandji M. Nouvelle technique de traitement chirurgicaldes luxations récidivantes isolées de l’extrémité inférieure du cubitus.J Chir (Paris). 1936;47:589e594.

8. Field J, Majkowski RJ, Leslie IJ. Poor results of Darrach’s procedureafter wrist injuries. J Bone Joint Surg Br. 1993;75(1):53e57.

9. Garcia-Elias M. Failed ulnar head resection: prevention and treat-ment. J Hand Surg Br. 2002;27(5):470e480.

10. Swanson AB. Implant arthroplasty for disabilities of the distal radio-ulnar joint: use of a silicone rubber capping implant following resectionof the ulnar head. Orthop Clin North Am. 1973;4(2):373e382.

11. Herbert TJ, van Schoonhoven J. Ulnar head replacement. Tech HandUp Extrem Surg. 2007;11(1):98e108.

12. Kakar S, Swann RP, Perry KI, Wood-Wentz CM, Shin AY,Moran SL. Functional and radiographic outcomes following distalulna implant arthroplasty. J Hand Surg Am. 2012;37(7):1364e1371.

13. van Schoonhoven J, Muhldorfer-Fodor M, Fernandez DL,Herbert TJ. Salvage of failed resection arthroplasties of the distalradioulnar joint using an ulnar head prosthesis: long-term results.J Hand Surg Am. 2012;37(7):1372e1380.

J Hand Surg Am. r V

14. van Schoonhoven J, Fernandez DL, Bowers WH, Herbert TJ. Salvageof failed resection arthroplasties of the distal radioulnar joint using anew ulnar head prosthesis. J Hand Surg Am. 2000;25(3):438e446.

15. Scheker LR, Martineau DW. Distal radioulnar joint constrainedarthroplasty. Hand Clin. 2013;29(1):113e121.

16. Kachooei AR, Chase SM, Jupiter JB. Outcome assessment afterAptis distal radioulnar joint (DRUJ) implant arthroplasty. Arch BoneJoint Surg. 2014;2(3):180e184.

17. Galvis EJ, Pessa J, Scheker LR. Total joint arthroplasty of the distalradioulnar joint for rheumatoid arthritis. J Hand Surg Am.2014;39(9):1699e1704.

18. Rahimtoola ZO, Hubach P. Total modular wrist prosthesis: a newdesign. Scand J Plast Reconstr SurgHand Surg. 2004;38(3):160e165.

19. Schuurman AH, Teunis T. A new total distal radioulnar joint pros-thesis: functional outcome. JHandSurgAm. 2010;35(10):1614e1619.

20. Coffey MJ, Scheker LR, Thirkannad SM. Total distal radioulnar jointarthroplasty in adults with symptomatic Madelung’s deformity. Hand(N Y). 2009;4(4):427e431.

21. Laurentin-Perez LA, Goodwin AN, Babb BA, Scheker LR. A studyof functional outcomes following implantation of a total distal radi-oulnar joint prosthesis. J Hand Surg Eur Vol. 2008;33(1):18e28.

22. Axelsson P, Sollerman C. Constrained implant arthroplasty as asecondary procedure at the distal radioulnar joint: early outcomes.J Hand Surg Am. 2013;38(6):1111e1118.

23. Degreef I, De Smet L. The Scheker distal radioulnar joint arthroplastyto unravel a virtually unsolvable problem. Acta Orthop Belg.2013;79(2):141e145.

24. Zimmerman RM, Jupiter JB. Outcomes of a self-constrained distalradioulnar joint arthroplasty: a case series of six patients. Hand (N Y).2011;6(4):460e465.

25. Hudak PL, Amadio PC, Bombardier C. Development of an upperextremity outcome measure: the DASH (disabilities of the arm,shoulder and hand) [corrected]. The Upper Extremity CollaborativeGroup (UECG). Am J Ind Med. 1996;29(6):602e608.

26. MacDermid JC, Turgeon T, Richards RS, Beadle M, Roth JH. Patientrating of wrist pain and disability: a reliable and valid measurementtool. J Orthop Trauma. 1998;12(8):577e586.

27. Cocchiarella L, Turk MA, Andersson G. Improving the evaluation ofpermanent impairment. JAMA. 2000;283(4):532e533.

28. Steyers CM, Blair WF. Measuring ulnar variance: a comparison oftechniques. J Hand Surg Am. 1989;14(4):607e612.

29. Tolat AR, Stanley JK, Trail IA. A cadaveric study of the anatomy andstability of the distal radioulnar joint in the coronal and transverseplanes. J Hand Surg Br. 1996;21(5):587e594.

30. Yang Z, Mann FA, Gilula LA, Haerr C, Larsen CF. Scaphopisoca-pitate alignment: criterion to establish a neutral lateral view of thewrist. Radiology. 1997;205(3):865e869.

31. Garcia-Elias M. Carpal instabilities and dislocations. In: Green DP,Hotchkiss RN, PedersonWC,Kozin SH, eds.Green’s Operative HandSurgery. 4th ed. London: Churchill Livingstone; 1999:865e928.

32. Lees VC, Scheker LR. The radiological demonstration of dynamiculnar impingement. J Hand Surg Br. 1997;22(4):448e450.

33. Scheker LR. Implant arthroplasty for the distal radioulnar joint.J Hand Surg Am. 2008;33(9):1639e1644.

34. Sauerbier M, Fujita M, Hahn ME, Neale PG, Berger RA. The dy-namic radioulnar convergence of the Darrach procedure and the ulnarhead hemiresection interposition arthroplasty: a biomechanical study.J Hand Surg Br. 2002;27(4):307e316.

35. Sauerbier M, Hahn ME, Fujita M, Neale PG, Berglund LJ,Berger RA. Analysis of dynamic distal radioulnar convergence afterulnar head resection and endoprosthesis implantation. J Hand SurgAm. 2002;27(3):425e434.

36. Berger RA. Implant arthroplasty for treatment of ulnar headresection-related instability. Hand Clin. 2013;29(1):103e111.

37. Peterson CA II, Maki S, Wood MB. Clinical results of the one-boneforearm. J Hand Surg Am. 1995;20(4):609e618.

38. Willis AA, Berger RA, Cooney WP III. Arthroplasty of the distalradioulnar joint using a new ulnar head endoprosthesis: preliminaryreport. J Hand Surg Am. 2007;32(2):177e189.

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APPENDIX A. Student t Test Comparison of Postoperative Values After Replacement of DRUJ With Standardor Extended Ulna Stem

Test Standard Stem (Average � SD) Extended Stem (Average � SD) P Value

Grip, kg 46 � 24 55 � 27 .35

Lifting, kg 16 � 6 17 � 6 .93

DASH 31 � 27 22 � 21 .34

PRWE 31 � 29 19 � 21 .18

VAS 2 � 3 2 � 1 .92

Pronation (degrees) 78 � 12 75 � 14 .55

Supination (degrees) 73 � 20 75 � 17 .77

Extension (degrees) 54 � 26 55 � 15 .86

Flexion (degrees) 56 � 21 55 � 19 .85

Radial deviation (degrees) 20 � 10 20 � 7 .88

Ulnar deviation (degrees) 27 � 12 29 � 11 .64

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APPENDIX B. Pearson Correlation Coefficients Between Functional Outcomes and Number of Previous Surgeries, Age of Patients, and Number ofPostoperative Complications

DASHPostoperative

DASHDifference

PRWEPostoperative

PRWEDifference

VAS PainPostoperative

VAS PainDifference

GripPostoperative Grip Difference

PronationPostoperative

PronationDifference

SupinationPostoperative

SupinationDifference

Previoussurgeries

0.21 0.762 0.401 0.497 0.416 0.298 0.361 0.647 0.863 0.905 0.594 0.042

Postoperativeunrelatedcomplications

0.056 0.368 0.271 0.428 0.414 0.752 0.267 0.621 0.95 0.348 0.256 0.628

Postoperativerelatedcomplications

0.643 0.913 0.674 0.39 0.391 0.365 0.725 0.538 0.299 0.828 0.027 0.708

Age 0.037 0.989 0.029 0.554 0.197 0.101 0.023 0.278 0.123 0.075 0.13 0.236

Entries in each cell represent Pearson correlation coefficients between corresponding row and column variables.

APTIS

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NT

INPATIENTSUNDER40

YEARSOFAGE

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APPENDIX C. Student t Test Used to Compare Outcomes Between Patients Who Underwent Previous SalvageProcedures and Those Who Did Not

Test With Salvage Procedure (Average � SD) Without Salvage Procedure (Average � SD) P Value

Grip 46.4 � 24.9 53.8 � 26.8 .410

Lifting 15 � 7.3 18.2 � 4.4 .170

DASH 31 � 27.2 23.5 � 22 .380

PRWE 29 � 28.4 24.3 � 25.8 .620

VAS 2.8 � 2.5 0.6 � 1.1 < .001*

Pronation 77.1 � 12.4 77.2 � 14.3 .990

Supination 70.9 � 20.4 77.2 � 16.2 .340

Extension 54.6 � 21.1 54.7 � 24.0 .980

Flexion 54.8 � 22.2 57.3 � 18.1 .730

Radial deviation 18.2 � 7.9 22.6 � 10.1 .220

Ulnar deviation 28.7 � 10.9 25.8 � 12.8 .520

*Statistically significant.

APPENDIX D. Student t Test Used to Compare Age and Number of Previous Procedures Between PatientsWho Developed ECU Tendonitis and Those Who Did Not

ECU Tendonitis (Average � SD) No ECU Tendonitis (Average � SD) P Value

Age 31 � 6.1 34.0 � 2.4 .16

Previous procedures 1.9 � 1.6 1.8 � 1.3 .88

APPENDIX E. Fisher Exact Test CalculatedBetween 2 Groups of Patients

Fisher Test P Value

Adipofascial flap* < .01†

Work type‡ .70

Extended/regular stem§ .13

Salvage procedurek .72

*Presence or absence of coverage of implant with the flap at the timeof DRUJ replacement.†Statistically significant.‡Manual versus desk activity.§Use of extended versus regular stem.kPatients who underwent versus those who did not undergo salvage

procedure.

APPENDIX F. Student t Test Comparison of Preoperative and Postoperative Ulna Translocation Indices

Test Preoperative (Average � SD) Postoperative (Average � SD) P Value

Chamay 0.33 � 0.03 0.31 � 0.04 .21

Di Benedetto 0.14 � 0.03 0.14 � 0.04 .24

Bowman 0.42 � 0.13 0.33 � 0.08 .05

McMurtry 0.29 � 0.04 0.26 � 0.04 .22

Schuind 0.87 � 0.03 0.88 � 0.05 .54

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