Letters to the Editor / The Journal of Foot & Ankle Surgery 53 (2014) 390–393 391

component subsidence, and the possibility of pathologic fracture;this will make proper revision much more difficult and morecostly.

Lastly, what is most disturbing is that one of us reviewed thispaper and unequivocally recommended against publicationbecause the concepts are so contrary to those of revision surgeryof the total ankle. Further, the novelty of these reports seems to bethe “metal” reinforcement and as such represents solving aproblem that does not exist. Above all, the premise of peer reviewshould be upheld and not ignored as appears to be in this case. Infact, one of the authors of this paper has written about the“rigors” of peer review: “This is because the publication ofresearch manuscripts is not only the desired outcome but alsorepresents a rigorous process that includes significant analysisand scrutiny of the research design, methods, results, and con-clusions, thereby improving the scientific validity of the infor-mation presented” (4). We strongly caution the readers of thesepapers against adoption of these concepts during revision totalankle surgery.

John M. Schuberth, DPM, FACFASChief, Foot and Ankle Surgery

Kaiser Foundation HospitalSan Francisco, California

Conflict of Interest: Dr. Roukis receives royalties for intellectual properties fromStryker Orthopaedics, Inc.

Jerome K. Steck, DPM, FACFASFoot and Ankle Specialist

Southern Arizona OrthopedicsTucson, Arizona

Jeffrey C. Christensen, DPM, FACFASPodiatric and Reconstructive Surgeon

Ankle and Foot Clinic of EverettEverett, Washington

References

1. Prissel MA, Roukis TS. Management of extensive tibial osteolysis with the Agility�total ankle replacement systems using geometric metal-reinforced poly-methylmethacrylate cement augmentation. J Foot Ankle Surg 53:101–107, 2014.

2. Nicholson JJ, Parks BG, Stroud CC, Myerson MS. Joint contact characteristics inAgility Total Ankle Arthroplasty. Clin Orth Relat Res 424:125–129, 2004.

3. Roukis TS. Incidence of revision after primary implantation of the Agility� totalankle replacement system: a systematic review. J Foot Ankle Surg 51:198–204,2012.

4. Roukis TS. Publication rates of manuscript presentations at the American College ofFoot and Ankle Surgeons Annual Scientific Conference between 1999 and 2008. JFoot Ankle Surg 50:416–419, 2011.

Revision of Agility Total Ankle�Replacements Using Agility�Components Is the Right Choice,Sometimes

Reply:We are pleased that the material we presented has generated

interest from our colleagues. We have identified 7 concerns thatDrs. Christensen, Schuberth, and Steck expressed with our JFASInstructional Course (1) within their Letter to the Editor.

1. We would like to address the concerns about the peer reviewprocess. As past editor of the Journal of Foot & Ankle Surgery�, Dr.Schuberth would surely attest to the rigors involved with the peerreview process in this journal. For clarity, following submission ofour manuscript, we received 3 separate reviewer comments andaddressed them by altering our text, adding pertinent supportingreferences, or otherwise revising the content. Based in large parton the queries thatwere raised by the reviewers’ comments, someof which are nearly identical to those raised in this Letter to theEditor,weadded audio commentary toprovide additional detailedanswers to these questions. As noted at the end of our article, thissupplementary material can be found in the online version atwww.jfas.org (http://dx.doi.org/10.1053/j.jfas.2013.07.005).

2. As pointed out by the letter’s authors, one of us (T.S.R.) previouslypublished on the incidence of revision for the Agility Total AnkleReplacement System� (DePuy Orthopaedics, Warsaw, IN) (2). Itshould be noted that all studies included in the systematic reviewinvolved an uncemented Agility Total Ankle Replacement�, which

is against the Food and Drug Administration (FDA) requirementsfor the 510k cleared use of this prosthesis (available at: http://www.accessdata.fda.gov/cdrh_docs/pdf5/k053569.pdf; accessed:January 24, 2014). We will use this opportunity to update that in-formation because an article on this topic has been publishedrecently (3). Although not definitive, the incidence of revision,defined as component replacement, ankle or tibiotalocalcanealarthrodesis, or below-knee amputation (4) after primary implan-tation of the uncemented Agility Total Ankle Replacement Sys-tem� is 10.2% (240 revisions/2,353 primary implants) at aweighted mean follow-up of 24.1 months. Specifically, 78.6% of therevisions consisted of implant component replacement followed byarthrodesis (18.7% of revisions) and below-knee amputation (4.7%of revisions). The mean follow-up is short; however, this is twicethe follow-up time covered in Drs. Schuberth and Christensen’sarticle (5) regarding revision total ankle replacement, whichinvolved 17 patients with a mean follow-up of only 12 months.Therefore, despite what the letter’s author’s claim, the literature(external to our cohort), in fact, supports that the Agility TotalAnkle Replacement System� can be revised with implantcomponent replacement more than three quarters of the time, atleast in the short term. Unfortunately, the outcomes of primaryimplantation of the most recent generationdthe Agility LP TotalAnkle Replacement System�dhave yet to be published (availableat: http://www.clinicaltrials.gov/ct2/show/NCT01366872?term¼agility&rank¼2; accessed January 24, 2014), and the abilityto perform successful revision of a failed earlier-generationAgility Total Ankle Replacement System�, in general, remainunanswered.As we clearly stated in our article, the technique we described wasrecommended for use in very select instances. There are otherways to address aseptic loosening of the tibial component of a totalankle replacement. The most commonly discussed alternative tothe proposed technique is impaction cancellous bone grafting,which has been well reported, and we have employed this

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technique for revision of an INBONE I Total Ankle Replacement�(WrightMedical Technology, Inc., Arlington, TN). Trabecularmetalsalso are available and may have application in specific instances;we, however, do not have experience with this technique inisolation. The purpose of the technique we described is not toobviate using alternate methods to address aseptic loosening and/or periprosthetic cystic defects but rather to increase the surgeon’sarmamentarium when faced with their management. In ouropinion, especially in the presence of massive osteolysis withcortical breach, trabecular metal and impaction bone graftingmay have limited application, and metal-reinforced poly-methylmethacrylate cement augmentation may be a plausiblealternative. Also, in elderly or co-morbid patients for whom asecond revisionwould not be considered viable, this technique alsocan be a “last ditch effort” to maintain a functional limb withlimited negative impact. To be clear, we are not proposing that thistechnique be employed universally. The figures that were ques-tioned were of the most advanced osteolysis we have observed inour series, an 80-year old patient who we believed would notbenefit from surgical options with greater morbidity (i.e., explan-tation with conversion to an alternate implant system or extendedtibiotalocalcaneal arthrodesis requiring extensive corticocan-cellous allograft). Ultimately, only extended surveillance willdetermine if the treatment rendered is efficacious, but at the 2-yearfollow-up mark he continues to do well without evidence ofprogressive osteolysis, pathologic fracture, or “cement disease,”despite the letter’s concerns about his specific radiographs.

3. The presence of osteolysis requiring treatment with a well-seatedtibial component has been commonly reported for a variety ofprosthesis designs (6–8). The idea that there are “standard prin-ciples” associated with revision total ankle replacement is purefantasy (9,10). This is very much a concept in evolution, and thecurrent approaches, especially conversions to the INBONE TotalAnkle Replacement System� (5,11,12), are technically complex,fraught with complications, and clearly not the only answers. Theability to convert to the Salto Talaris� or Salto XT� system(Tornier, Inc., Bloomington, MN) is compelling but as of yetunproven (13). The ability to use custom devices (14) hasbeen discontinued by the FDA (available at: http://www.fda.gov/ICECI/EnforcementActions/WarningLetters/2011/ucm287552.htm;accessed January 24, 2014). Alas, there is no “standard” for totalankle replacement revision, which is why it is important forpeople actually doing this work to share information and engagein healthy dialog for the patients’ benefit.

4. The use of metal and polymethylmethacrylate in total joint re-placements is actually an old technique that has its roots in revisionof total knee replacements (15), and it has long-term follow-upstudies supporting its use in select situations (16). Any of thecomponent materials can result in macrophage/osteoclast/osteo-blast mediated cellular destruction, and polymethylmethacrylate isobviously one of these materials (6). We find it interesting that theletter’s authors are so concerned about the use of poly-methylmethacrylate cement when Dr. Steck published an article inwhich he stated, “.in patients with severe osteoporosis, cement isadvisable to create a stable implant” and, in Figure 16 of this samework, demonstrated cement augmentation during revision surgeryfor support of a subsided Agility Total Ankle Replacement� tibialcomponent (17). We find the connection between our proposedtechnique, inwhich the tibial component is stable andwe are fillingthe defect with metal and cement, and the use of

polymethylmethacrylate cement for anchorage of first generationprostheses to the soft metaphyseal bone in the distal tibiauninformed.

5. The weightbearing lateral stress images were shown to providecomparison over time; these images can demonstrate motion be-tween the metal components and bone/cement. They are relativelylow cost, and radiation exposure is minimal. Wemaintain that theseradiographic views provide valuable surveillance of primary or revi-sion total ankle replacements. The radiation is on par with thatabsorbed by the patients following the protocol for total ankle sur-veillance that Drs. Schuberth and Christensen published (18), whichinvolves serial postoperative range of motion images taken using afluoroscopy image intensification unit. We find the fluoroscopyapproachof lessbenefit thanweightbearingstress lateral radiographsbecause, with fluoroscopy, no integrated digital imaging system canbeemployed to accuratelymeasure the angular differences and thereis no ability to magnify the images. In addition, fluoroscopy is notreadily available in clinical practice, making its application limited.

6. We clearly described that the purpose of the coiled metallic pinswithin the osseous defect was to provide broad contact betweenthe remaining bone and thus, at least in theory, to offer somesupport against collapse/compression and to reduce the volumeof polymethylmethacrylate cement used. The concern about“mixing metals” is pure theory (19).

7. As to the remaining “biologicallyactivematerial,” at the timeofeachrevision, all obviously pathologic tissue was excised from theosseous cavities using hand-held instruments and a hydrosurgerydissection tool until nothing but bleeding bone, clean metal com-ponents, or fibrous membrane remained, free of particulate mate-rials. In some instances, such as the figures referenced, there wereradiographic findings of cystic changes adjacent to themain defect,but no obvious connection between the working space and thecontained cysts could be identified. It remains a matter for conjec-ture as to whether the remaining cystic materials will expand andcreate further problems or remain contained as they have so farduring the continuedsurveillanceof thesepatients. The reference tocost is interesting because the direct product cost in U.S. dollars ofthe technique employed involves the following: Agility� talarcomponent z $3,700; Agility� polyethylene insert z $750; fullbatch polymethylmethacrylate cement with antibiotic z $270;and 3 Steinmann pins z $15. This totals z $4,735. In contrast,at our institution, conversion to an INBONE Total Ankle Replace-ment� system with metallic fusion rods as Drs. Schuberth andChristensen’s have proposed (5) has averaged z $20,000. Wemaintain that in select patients, the technique we demonstrated iscost-effective, at least in the short-term. Once our mid-term andlong-term data is available, wewill submit this for peer review andpublication. Of course, any meaningful discussion of costs wouldrequire a thorough cost-effectiveness analysis, one that definesoutcomes in terms of quality of life units and incremental cost dif-ferences, and one that is based on a suitable sample of patients.In conclusion, we maintain that the technique we presented isrelatively simple, inexpensive, and useful for the indications wedefined. We agree with Whittaker et al (15) regarding jointreplacement. They wrote, “When selecting the method of recon-struction and the materials for revision surgery, the potential forfuture further revision must be considered together with the lifeexpectancy, functional demand and comorbidities of the patient.”Clearly, there is a real need for outcome studies to evaluate pa-tients undergoing revision total ankle replacement for the current

Letters to the Editor / The Journal of Foot & Ankle Surgery 53 (2014) 390–393 393

prosthesis systems available in the United States, and future effortsought to be directed in this area.

Thomas S. Roukis, DPM, PhD, FACFASMark A. Prissel, DPM (PGY-III)

Department of OrthopedicsPodiatry, and Sports Medicine

Gundersen Health SystemLa Crosse, Wisconsin

References

1. Prissel MA, Roukis TS. Management of extensive tibial osteolysis with the AgilityTotal Ankle Replacement Systems using geometric metal-reinforced poly-methylmethacrylate cement augmentation. J Foot Ankle Surg 53:101–107, 2014.

2. Roukis TS. Incidence of revision after primary implantation of the Agility total anklereplacement system: a systematic review. J Foot Ankle Surg 51:198–204, 2012.

3. Criswell BJ, Douglas K, Naik R. High revision and reoperation rates using the AgilityTotal Ankle System. Clin Orthop Rel Res 470:1980–1986, 2012.

4. Henricson A, Carlsson A, Rydholm U. What is a revision of total ankle arthroplasty?Foot Ankle Surg 17:99–102, 2011.

5. Schuberth JM, Christensen JC, Rialson JA. Metal-reinforced cement augmentationfor complex talar subsidence in failed total ankle arthroplasty [JFAS instructionalcourse]. J Foot Ankle Surg 50:766–772, 2011.

6. Gaden MT, Ollivere BJ. Periprosthetic aseptic osteolysis in total ankle replacement:cause and management. Clin Podiatr Med Surg 30:145–155, 2013.

7. Besse J-L, Lienhart C, Fessy M-H. Outcomes following cyst curettage and bonegrafting for management of periprosthetic cystic evolution after AES total anklereplacement. Clin Podiatr Med Surg 30:157–170, 2013.

8. Espinosa N, Wirth SH. Revision of the aseptic and septic total ankle replacement.Clin Podiatr Med Surg 30:171–185, 2013.

9. Bess J-L, Bevernage BD, Leemrijse T. Revision of total ankle replacements. Tech FootAnkle Surg 10:176–188, 2011.

10. Barg A, Horsiserger M, Paul J, et al. Salvage procedures after failed total anklereplacement. Fuss Sprung 11:228–237, 2013.

11. DeVries JG, Scott RT, Berlet GC, et al. Agility to INBONE: anterior and posteriorapproaches to the difficult revision total ankle replacement. Clin Podiatr Med Surg30:81–96, 2013.

12. Meeker J,Wegner N, Francisco R, et al. Revision techniques in total ankle arthroplastyutilizing a stemmed tibial arthroplasty system. Tec Foot Ankle 12:99–108, 2013.

13. Jonck JH, Myerson MS. Revision total ankle replacement. Foot Ankle Clin 17:687–706, 2012.

14. Ketz J, Myerson M, Sanders R. The salvage of complex hindfoot problems with useof a custom talar total ankle prosthesis. J Bone Joint Surg Am 94:1194–1200, 2012.

15. Whittaker JP, Dharmarajan R, Toms AD. The management of bone loss in revisiontotal knee replacement. J Bone Joint Surg Br 90:981–987, 2008.

16. Ritter MA, Keating EM, Faris PM. Screw and cement fixation of large defects in totalknee arthroplasty: a sequel. J Arthroplasty 8:63–65, 1993.

17. Steck JK, Anderson JB. Total ankle arthroplasty: indications and avoiding compli-cations. Clin Podiatr Med Surg 26:303–324, 2009.

18. Schuberth JM,McCourtMJ, Christensen JC. Interval changes in postoperative range ofmotion of Salto-Talaris total ankle replacement. J Foot Ankle Surg 50:562–565, 2011.

19. Zartman KC, Berlet GC, Hyer CF, et al. Combining dissimilar metals in orthopaedicimplants: revisited. Ankle Spec 4:318–323, 2011.