Given the challenges of total ankle replacement, these authors provide a historical overview of one of the early implants, review common complications and offer salient insights on revisional treatment.
It is generally accepted that the early history of total ankle replacement arthroplasty consisted of uninterrupted failure and accordingly was rendered nearly extinct.
1-7 Dissatisfaction with ankle joint arthrodesis, the success of total hip and knee implant arthroplasties, and the efforts of surgeons and industry to address the problems associated with prior implant designs have resulted in renewed interest in total ankle replacement.
8-12
One total ankle replacement available for use in the U.S. is the Agility
® Total Ankle Replacement System (DePuy Orthopaedics). Frank G. Alvine, MD, who invented the device, states that the prosthesis was designed around three specific areas of study: (1) CAD-CAM computer analysis of 100 normal ankle radiographs; (2) modes of failure (specifically subsidence, impingement and malalignment) of previous generations of total ankle replacements; and (3) surgical approach including accuracy of insertion and instrumentation including an external fixation device to tension the ligaments.
13,14
The design process started in 1978 and the first patient received the implant in 1985. It was subsequently marketed in 1992 as the “DePuy Alvine Total Ankle Prosthesis.”
15 Between 1985 and 2007, the implant went through a total of four generations and seven phases of implant improvement.
13,14,16 Of note, the ankle implant is FDA approved only for use with polymethylmethacrylate (PMMA) cement fixation as demonstrated in the technique guides.
17,18
Between 1985 and 1998, there were several early phases of improvement with the implant. These improvements included thickening of the tibial titanium component; augmenting the posterior dimensions of the tibial component; changing the metallurgy of the talus from titanium to cobalt-chrome; increasing the sizes from three to six; developing a rectangular “revision” talar component; and adding revision ultra-high molecular weight polyethylene (UHMWPE) with an additional 2 mm thickness as well as a half-column design for the 0-mm UHMWPE insert to make revision insertion of the bottom-loaded insert easier.
14 These changes were based on the continued effort of the inventor to refine the implant and improve his patient’s outcomes as well as the release of the implant to a select group of orthopaedic surgeons across the U.S. in 1993 and their ongoing feedback.
Following these changes, the implant became widely available to surgeons who completed a company-sponsored surgical skills course at the American Academy of Orthopaedic Surgeons Learning Center in Rosemont, Illinois, starting in 1998.
16,19 The Agility Total Ankle Replacement System was the only FDA-cleared ankle replacement readily available in the U.S. until 2007. As a result, the Agility Total Ankle Replacement System was the most widely implanted ankle replacement in the U.S. for over a decade. Complications began to surface that predominantly involved three modes of failure: (1) syndesmosis nonunion and subsequent tibial component malalignment or loosening; (2) talar component subsidence; and (3) aseptic osteolysis.
14,16,19-27 The last two modes of failure usually coincide.
As a result, the next changes to the Agility Total Ankle Replacement System occurred in 2002 with alterations to the talar component, making it 18 percent wider, shortening the length of the fin and adding the ability to create a custom-stemmed talar component to replace lost height due to subsidence and cystic changes, and perform concomitant arthrodesis of the subtalar joint.
9,14 This was followed in 2003 with the ability to create a custom-stemmed total talar replacement and in 2004 with the use of a plate and screw construct to enhance syndesmosis union.
14,28,29 Unfortunately, as of December 8, 2011, any Agility Total Ankle Replacement System custom-stemmed talar component is no longer available for clinical use due to U.S. FDA regulation and the availability of this in the future remains uncertain.
30
The final changes occurred in 2007 after surgeons and engineers developed the Agility
® LP Total Ankle System, which included three major modifications. The first modification was the development of a broad-based “winged” and 2 mm thicker talar component to reduce the incidence of subsidence with primary implantation, and allow for the ability to revise previously inserted talar components and a corresponding shortening or “lowering the profile” of the tibial component side walls by 2 mm to accommodate the talar wings.
A second modification was the ability to mismatch component sizes by upsizing one talar component relative to the tibial component. This allows for more precise insertion and revision capabilities since the tibial component from an earlier generation can remain in situ and one can insert a bottom-loaded full column +2 mm UHMWPE into an LP talar component. The third modification was developing a front-loaded polyethylene locking mechanism with 0 mm (i.e., neutral) and +1 mm thickness, making subsequent replacement easier.
14,19,31,32
Unfortunately, a recently completed but not yet published U.S. National Institutes of Health two-year outcome study of 50 non-cemented Agility LP Total Ankle Systems revealed complications similar to the older Agility designs.
33 Additionally, the Agility LP Tibial Tray is no longer being manufactured. This foretells the end of the LP version as a primary total ankle replacement and complicates revision options.
There has been much attention focused on intraoperative complications (i.e., malleolar fracture, nerve or tendon injury) and incision healing-related problems (i.e., wound coverage, infection). However, the intermediate and long-term complications (i.e., aseptic osteolysis, subsidence, component loosening and progressive malalignment) require careful consideration as the secondary procedure options for revision remain limited and the potential need to revise previously revised implants exists.
2,3,9-13,16,19,20,34-61
Although not definitive, researchers have recently determined a 10.2 percent (240 revisions/2,353 primary implants) incidence of revision, defined as component replacement, ankle or tibio-talo-calcaneal arthrodesis, or below-knee amputation.
61,62 In a detailed systematic review, 78.6 percent of the revisions consisted of implant component replacement followed by arthrodesis (18.7 percent of revisions) and below-knee amputation (4.7 percent of revisions).
63 Unfortunately, the outcomes of primary implantation of the most recent generation, the Agility LP Total Ankle Replacement System, and the ability to perform successful revision of a failed earlier-generation Agility Total Ankle Replacement System in general remain unanswered.
When A Distal Tibiofibular Syndesmosis Nonunion Occurs
Nonunion of the distal tibiofibular syndesmosis develops secondary to premature weightbearing, inadequate preparation of the syndesmosis for arthrodesis, metal fixation failure and the presence of unrecognized post-traumatic distal-lateral tibial necrosis. The surgeon should resect the nonunion until only healthy, viable bone remains. This frequently results in significant bone loss. While most publications recommend the use of impaction cancellous bone grafting supplemented with a fibular side plate and multiple fibula-pro-tibia compression screw stabilization, this approach mandates protracted periods of non-weightbearing, and union is often incomplete, making further revision likely.
9,29,42,50,51,64
The subsequent revision is even more complex due to the multiple osseous defects in the fibula from prior hardware insertion and removal, and the need for resection of additional bone about the syndesmosis nonunion site resulting in significant osseous defects. Instead, we recommend the implantation of multiple 0.062-inch Kirschner wires bent and twisted into various geometric shapes (i.e., coils, crosses, pyramids, etc.) within the osseous defect followed by the insertion of polymethylmethacrylate cement, adhering to the principles of cemented total knee arthroplasty (see photos D-F on page 53).
65,66
What You Should Know About Aseptic Osteolysis
The development of aseptic osteolysis following total ankle replacement is the major cause of failure. It increases with time and results in loss of fixation of the prosthesis. This process involves a macrophage mediated osteolytic destruction of periprosthetic bone secondary to phagocytosable UHMWPE wear debris usually as a result of component malposition.
60,67-79 Specific to the Agility Total Ankle Replacement Systems, aseptic osteolysis about the tibial tray may or may not involve subsidence and/or component loosening. Aseptic osteolysis involving the talar component nearly universally involves varying degrees of subsidence and component loosening. The resultant bone loss can be quite extensive.
37,80
When Aseptic Osteolysis Involves The Tibial Component
When it comes to aseptic osteolysis about the tibial tray without subsidence, one should resect all cyst contents and proceed to implant multiple 0.062-inch Kirschner wires bent and twisted into geometric shapes within the osseous defect with subsequent insertion of polymethylmethacrylate cement (see photos F-H on page 54). Aseptic osteolysis about the tibial tray with subsidence remains a challenge. The only options are explantation and conversion to the INBONE
® Total Ankle Replacement Systems (Wright Medical Technology) (see photos on page 56) or when more bone remains, coversion to the Salto Talaris
™ Total Ankle Prosthesis (Tornier) or tibio-talo-calcaneal arthrodesis with bulk femoral head allograft and retrograde compression intramedullary nail fixation.
45,48,84-86
Once the Salto Talaris
® XT Revision Total Ankle Prosthesis (Tornier) is available for use in the U.S., the options for revision total ankle replacement will become more plentiful as this system includes stemmed tibia and talar components, augmented talar components, and a large array of thick UHMWPE inserts.
How To Address Aseptic Osteolysis That Affects The Talar Component
Aseptic osteolysis involving the talar component occurs in three stages of severity based on the degree of collapse into the talar body (see above radiographs) and seems to be correlated with the degree of osseous ongrowth to the porous coated undersurface of the talar component and keel/peg design characteristics.
87-89 The options for revision of the talar component depends on whether the failed system was an Agility or Agility LP Total Ankle Replacement System. The original, flanged and posterior augmented talar components are no longer available for use.
30
We should note that the LP talar component has the same height as the same size original, flanged or posterior augmented talar components. However, the articulating top surface of the LP talar component is much broader than these other designs and results in comparably less frontal and transverse plane motion. Additionally, depending on the size you use, the revision talar component adds between 1.5 mm and 2.8 mm of height.
Finally, several UHMWPE insert options exist depending on the specific version of the Agility or Agility LP Total Ankle Replacement System undergoing revision. Specifically, if the failed system is an Agility Total Ankle Replacement System, then the revision options include: (1) a same size revision talar component with a bottom-loaded full or half-column 0 mm UHMWPE insert; (2) a same size revision talar component with a bottomloaded full column +2 mm UHMWPE insert; or (3) a same size LP talar component with a bottom-loaded full column +2 mm UHMWPE insert.
However, if the failed system is an Agility LP Total Ankle Replacement System, then one may consider the following revision options.
(1) A same size revision talar component with a front-loaded 0 mm UHMWPE insert.
(2) A same size revision talar component with a front-loaded +1 mm UHMWPE insert (see photos on page 53).
(3) A same size LP talar component with a front-loaded 0 mm UHMWPE insert. (Note: this is only possible if one corrects the talar component subsidence back to its original state with the use of polymethylmethacrylate cement augmentation. Otherwise, an unstable joint will result.)
(4) A same size LP talar component with a front-loaded +1 mm UHMWPE insert.
(5) A one size larger revision talar component with a front-loaded mismatch UHMWPE insert (i.e., retained size 4 LP tibial tray with size 5 revision talar component and size 5/4 mismatch UHMWPE insert).
(6) A one size larger LP talar component with a front-loaded mismatch UHMWPE insert. We should note that the mismatch UHMWPE insert does not independently add any additional height.
As with tibial component subsidence, we recommend implanting multiple 0.062-inch Kirschner wires bent and twisted into geometric shapes packed within the osseous defect, and the subsequent insertion of polymethylmethacrylate cement to augment the deficient talar body.
65,90 It is important to achieve proper talar height so the medial and lateral ankle ligaments are properly tensioned and the mechanical axis of the ankle joint is restored. Whenever possible, we try to achieve a talar height that allows for use of a 0 mm UHMWPE insert and a non-revision talar component in order to preserve these options for a future revision if necessary.
Keys To Addressing Aseptic Osteolysis When It Affects Tibial And Talar Components
When it comes to aseptic osteolysis involving both the tibial tray and talar components, surgeons can manage this with either retention of the Agility Total Ankle Replacement System tibial tray and replacement of the talar component and UHMWPE adhering to the aforementioned options, or explantation and conversion to the INBONE Total Ankle Replacement Systems.
The use of an anterior distal tibia plate abutting the superior portion of the tibial tray can be invaluable to support or buttress the tibial tray realignment, and one can also employ this plate as a fixation point for a modified Evans peroneal tendon lateral ankle stabilization.
31,91 Finally, it is frequently necessary to perform soft-tissue balancing most commonly with release of the deltoid ligament complex and/or a posterior tibial tendon recession and lateral ankle stabilization with a modified Evans peroneus brevis tendon transfer secured to the distal tibia or fibula.
40,41,92,93
In regard to explantation of the failed Agility total ankle replacement and implantation of a permanent polymethylmethacrylate cement spacer, conversion to an extended tibio-talo-calcaneal arthrodesis with bulk femoral head allograft or a below-knee amputation, surgeons should reserve these options for non-reconstructable talar body destruction, non-reconstructable soft tissue defects, unremitting pain with joint stiffness or uncontrollable infection.
84-86,93 Arthrodesis or below-knee amputation are also indicated in situations in which the patient does not desire or is medically unable to undergo revision surgery.
In Conclusion
Failure of the Agility total ankle replacement system leading to revision involves two main etiologies: (1) distal tibio-fibular syndesmosis nonunion and (2) aseptic osteolysis of the tibial and/or talar components with or without secondary component subsidence. Depending on the alignment and integration of the components and size of the osseous defect, multiple revision possibilities exist such that surgeons can revise approximately 80 percent of the failed systems. The revision possibilities include reinforcement of the osseous defects utilizing polymethylmethacrylate cement with or without geometric metal augmentation; use of revision or LP talar components and UHMWPE exchange; or conversion to the INBONE or Salto Talaris Total Ankle Replacement Systems.
Although they are no longer available for use in the U.S., custom stemmed tibial and/or talar components represented viable options and should also be relevant in the future once the FDA loosens the current restrictions and the Salto Talaris XT Revision Total Ankle Prosthesis (Tornier) is cleared for use. Surgeons should reserve arthrodesis or below-knee amputation for select non-reconstructable cases or situations in which the patient does not desire or is medically unable to undergo revision surgery.
Dr. Roukis is an attending foot and ankle surgeon within the Department of Orthopaedics, Podiatry, and Sports Medicine with the Gundersen Health System in La Crosse, Wisconsin. He is a Fellow and President-Elect of the American College of Foot and Ankle Surgeons.
Dr. Prissel is a third-year resident with the Gundersen Medical Foundation in La Crosse, Wisconsin.
References
1. Carlsson ÅS. Revision of different ankle prostheses. In: Koföed H (ed): Current Status of Ankle Arthroplasty. Ch. 11, Springer, Berlin, 1998: pp. 50-56.
2. Easley ME, Adams SB, Hembree WC, DeOrio JK. Results of total ankle arthroplasty. J Bone Joint Surg Am. 2011;93(15):1455-1468.
3. Gougoulias NE, Khanna A, Maffulli N. How successful are current ankle replacements? A systematic review of the literature. Clin Orthop Relat Res. 2010;468(1):199-208.
4. Roukis TS, Prissel MP. Registry data trends of total ankle replacement use. J Foot Ankle Surg. 2013;52(6):728-735.
5. Prissel M, Roukis TS. Incidence of revision following primary insertion of the STAR™ implant: A systematic review. Clin Podiatr Med Surg. 2013;30(2):237-250.
6. Teasdale R, Pfeffinger L, Murray WR. The total ankle arthroplasty: a joint too far (Published abstract presented at the Western Orthopedic Association). Orthop Transact. 1981;5:84.
7. van den Heuvel A, Van Bouwel S, Dereymaeker G. Total ankle replacement: Design evolution and results. Acta Orthop Belg. 2010;76(2):150-161.
8. Haddad SL, Coetzee JC, Estok R, et al. Intermediate and long-term outcomes of total ankle arthroplasty and ankle arthrodesis. J Bone Joint Surg Am. 2007;89(9):1899-1905.
9. Myerson MS, Won HY. Primary and revision total ankle replacement using custom-designed prosthesis. Foot Ankle Clin. 2008;13(3):521-538.
10. SooHoo NF, Zingmond DS, Ko CY. Comparison of reoperation rates following ankle arthrodesis and total ankle arthroplasty. J Bone Joint Surg Am. 2007;89(10):2143-2149.
11. Labek G, Klaus H, Schlichtherle R, et al. Revision rates after total ankle arthroplasty in sample-based clinical studies and national registries. Foot Ankle Int. 2011;32(8):740-745.
12. Labek G, Thaler M, Janda W, et al. Revision rates after total joint replacement: Cumulative results from worldwide joint register datasets. J Bone Joint Surg Br. 2011;93(3):293-297.
13. Alvine FG. Total ankle arthroplasty: New concepts and approach. Contemp Orthop. 1991;22(4):397-403.
14. Alvine FG. The Agility™ ankle replacement: the good and the bad. Foot Ankle. 2002;7(4):737-753.
15. https://www.accessdata.fda.gov/cdrh_docs/pdf5/K053569.pdf .
16. Alvine FG. Design and development of the Agility™ ankle. Foot Ankle Spec. 2009;2(1):45-50.
17. www.depuy.comhttps://s3.amazonaws.com/HMP/hmp_ln/imported/products/files/DO_Agility_Ankle_Surgtech_DR_Primary_Revision_Steps_0601-24-050r2.pdf .
18. www.depuy.comhttps://s3.amazonaws.com/HMP/hmp_ln/imported/products/files/DO_Agility_Ankle_LP_Surgtech_0612-50-505.pdf . Accessed: August 2, 2013.
19. Cerrato R, Myerson MS. Total ankle replacement: the Agility™ LP prosthesis. Foot Ankle Clin. 2008;13(3):485-494.
20. Claridge RJ, Sagherian BH. Intermediate term outcome of the Agility™ total ankle arthroplasty. Foot Ankle Int. 2009;30(9):824-835.
21. Gould JS. Revision total ankle arthroplasty. Am J Orthop. (Belle Mead NJ) 2005;34(8):361.
22. Groth HF, Fitch HF. Salvage procedures for complications of total ankle arthroplasty. Clin Orthop Rel Res. 1987;224:244-250.
23. Hintermann B. Complications of total ankle arthroplasty. In: Hintermann B (ed): Total Ankle Arthroplasty: Historical Overview, Current Concepts, and Future Perspectives. Ch. 11, Springer, New York, 2005, pp. 163-184.
24. Hintermann B. Salvage of failed total ankle arthroplasty, Procedure 26. In: Pfeffer GB, Easley ME, Frey C, Hintermann B, Sands AK. Ed. Operative Techniques: Foot and Ankle Surgery. Philadelphia: Saunders. 2010:325-340.
25. Hosman AH, Mason RB, Hobbs T, et al. A New Zealand national joint registry review of 202 total ankle replacements followed for up to 6 years. Acta Orthop. 2007;78(5):584-591.
26. Krause FG, Windolf M, Penner MJ, Wing KJ, Younger ASE. Impact of complications in total ankle replacement and ankle arthrodesis analyzed with a validated outcome measurement. J Bone Joint Surg Am. 2011;93(9):830-839.
27. Pyevich MT, Saltzman CL, Callaghan JJ, et al. Total ankle arthroplasty: A unique design. Two to twelve-year follow-up. J Bone Joint Surg Am. 1998;80(10):1410-1420.
28. Alvine GS, Steck JK, Alvine FG. Early Results for the Agility™ Stemmed Talar Revisional Component for total ankle arthroplasty. Cited in: Trepman E, Lutter LD, Richardson EG, Brodsky JW, Donley BG. Special report: Highlights of the 22nd Annual Summer Meeting of the American Orthopaedic Foot and Ankle Society, La Jolla, California, July 14–16, 2006. Foot Ankle Int. 2007;28(5):646-653.
29. Jung H-G, Nicholson JJ, Parks B, et al. Radiographic and biomechanical support for fibular plating of the Agility™ total ankle. Clin Orthop Rel Res. 2004;424:118-124.
30. https://www.fda.gov/ICECI/EnforcementActions/WarningLetters/2011/ucm287552.htm .
31. Castro MD. Insufficiency fractures after total ankle replacement. Tech Foot Ankle Surg. 2007;6:15-21.
32. Castro MD. Agility low profile: short-term update and representative case presentation. Seminars Arthroplasty. 2010;21:267-274.
33. https://www.clinicaltrials.gov/ct2/show/results/NCT01366872?term=ankle+replacement%27&rank=9§=X430125 . Accessed August 13, 2013.
34. Alvine FG, Conti SF. Die Agility™-Sprunggelenkprothese: Mittel- und langfristige Erfahrungen. Orthopäde. 2006;35(5):521-526.
35. Coetzee JC. Prospective outcome study on the Agility™ total ankle replacement: minimum 3-year follow-up. American Academy of Orthopaedic Surgeons Annual Meeting, Oral Podium Presentation 071, San Diego, CA, 14-17 February 2007.
36. Criswell BJ, Douglas K, Naik R, Thomson AB. High revision and reoperation rates using the Agility™ total ankle system. Clin Orthop Rel Res. 2012;470(7):1980-1986.
37. Glazebrook MA, Arsenault K, Dunbar M. Evidence-based classification of complications in total ankle arthroplasty. Foot Ankle Int. 2009;30(10):945-949.
38. Glazebrook M, Arsenault K, Dunbar M. Longevity of modern ankle replacement arthroplasty: Survivorship and mechanisms of failure. In: Coetzee JC, Hurwitz SR (eds): Arthritis & Arthroplasty: the Foot and Ankle, Ch. 21, Saunders Elsevier, Philadelphia, 2010, pp. 187-194.
39. Gupta S, Ellington JK, Myerson MS. Management of specific complications after revision total ankle replacement. Semin Arthro. 2010;21:310-319.
40. Haddad SL. Recurrent varus following total ankle arthoplasty. In: Coetzee JC, Hurwitz SR (eds): Arthritis & Arthroplasty: the Foot and Ankle, Ch. 14, Saunders Elsevier, Philadelphia, 2010, pp. 125-132.
41. Haddad SL. Recurrent valgus following total ankle arthoplasty. In: Coetzee JC, Hurwitz SR (eds): Arthritis & Arthroplasty: the Foot and Ankle, Ch. 15, Saunders Elsevier, Philadelphia, 2010, pp. 133-139.
42. Haddad SL. Revision Agility total ankle arthroplasty. In: Easley ME, Wiesel SW (eds): Operative Techniques in Foot and Ankle Surgery, Ch. 76, Lippincott Williams & Wilkins, Philadelphia, 2011, pp. 622-642.
43. Haskell A. Total ankle arthroplasty: the U.S. experience. In: Saxena A. (ed): International Advances in Foot and Ankle Surgery, Ch. 43, Springer, London, 2012, pp. 467-487.
44. Horowitz EJ, Gould JS, Fleisig GS, Fowler R. Outcome analysis of Agility™ total ankle replacement with prior adjunctive procedures: two to six year follow-up. Foot Ankle Int. 2007;28(3):308-312.
45. Jonck JH, Myerson MS. Revision total ankle replacement. Foot Ankle Clin. 2012;17(4):687-706.
46. Kopp FJ, Patel MM, Deland JT, et al. Total ankle arthroplasty with the Agility™ prosthesis: Clinical and radiographic evaluation. Foot Ankle Int. 2006;27(2):97-103.
47. Knecht SI, Estin M, Callaghan JJ, et al. The Agility™ total ankle arthroplasty: Seven to sixteen-year follow-up. J Bone Joint Surg Am. 2004;86-A(6):1161-1171.
48. McCollum G, Myerson MS. Failure of the Agility™ total ankle replacement system and the salvage options. Clin Pod Med Surg. 2013;30(2):207-223.
49. Myerson MS. Total ankle replacement. In: Myerson MS (ed): Reconstructive Foot and Ankle Surgery, 1st ed. Ch. 9-1, Elsevier, Philadelphia, 2005, pp. 225-251.
50. Myerson MS. Total ankle replacement. In: Myerson MS (ed): Reconstructive Foot and Ankle Surgery: Management of Complications, 2nd ed, Ch. 24, Elsevier Saunders, Philadelphia, 2010, pp. 271-294.
51. Myerson MS. Revision total ankle replacement, Chapter 25. In: Myerson MS. Ed. Reconstructive Foot and Ankle Surgery: Management of Complications, 2nd ed, Philadelphia: Elsevier Saunders. 2010:295-316.
52. Raikin SM, Myerson MS. Avoiding and managing complications of the Agility total ankle replacement system. Orthopaedics. 2006;29(10):931-938.
53. Rippstein PF. Clinical experiences with three different designs of ankle prosthesis. Foot Ankle Clin. 2002;7(4):817-831.
54. Saltzman CL, Alvine FG. The Agility™ total ankle replacement. AAOS Instr Course Lect. 2002;51:129-133.
55. Sanders RW. Failed total ankle arthroplasty. In: Nunley JA, Pfeffer GB, Sanders RW, Trepman E (eds): Advanced Reconstruction: Foot and Ankle, Ch. 30, American Academy of Orthopaedic Surgeons, Rosemont, IL, 2004: pp. 201-208.
56. Sanders R. Recognition and salvage of the failed ankle replacement arthroplasty. In: Coetzee JC, Hurwitz SR (eds): Arthritis & Arthroplasty: the Foot and Ankle, Ch. 20, Saunders Elsevier, Philadelphia, 2010; pp. 178-186.
57. Schuberth JM, Patel S, Zarutsky E. Perioperative complications of the Agility™ total ankle replacement in 50 initial, consecutive cases. J Foot Ankle Surg. 2006;45(3):139-146.
58. Spirit AA, Assal M, Hansen ST. Complications and failure after total ankle arthroplasty. J Bone Joint Surg Am. 2004;86-A(6):1172-1178.
59. Steck JK, Anderson JB. Total ankle arthroplasty: Indications and avoiding complications. Clin Podiatr Med Surg. 2009;26(2):303-324.
60. Van Boerum DH, Morgan JM, Dockter ER. Periprosthetic fractures: intraoperative and postoperative. In: Coetzee JC, Hurwitz SR (eds): Arthritis & Arthroplasty: the Foot and Ankle, Ch. 17, Saunders Elsevier, Philadelphia, 2010, pp. 146-152.
61. Vienne P, Nothdurft P. OSG-Totalendoprosthese Agility™: Indikationen, Operationstechnik und Ergebnisse. Fuss Sprungg. 2004;2:17-28.
62. Henricson A, Carlsson Å, Rydholm U. What is a revision of total ankle replacement? Foot Ankle Surg. 2011;17(3):99-102.
63. Roukis TS. Incidence of revision after primary implantation of the Agility Total Ankle Replacement System: a systematic review. J Foot Ankle Surg. 2012;51(2):198-204.
64. Ebeling PB, Coetzee JC. Syndesmosis fusion in the Agility™ total ankle arthroplasty. In: Coetzee JC, Hurwitz SR (eds): Arthritis & Arthroplasty: the Foot and Ankle, Ch. 16, Saunders Elsevier, Philadelphia, 2010; pp. 140-145.
65. Prissel MA, Roukis TS. Management of extensive tibial osteolysis with the Agility™ total ankle replacement systems using geometric metal-reinforced cement augmentation. J Foot Ankle Surg. 2014;53(1):101-7.
66. Cawley DT, Kelly N, McGarry JP, et al. Instructional Review: Knee: Cementing techniques for the tibial component in primary total knee replacement. Bone Joint J. 2013;95:295-300.
67. Assal M, Al-Shaikh R, Reiber BH, et al. Fracture of the polyethylene component in an ankle arthroplasty: a case report. Foot Ankle Int. 2003;24(12):901-903.
68. Barg A, Knupp M, Hintermann B. Revisions nach endoprostheticher Versorgung des oberen Spruggelenks, In: Neumann HS, Holz U (eds): AE-Manual de Endoprothetik: Sprunggelenk und Fuß, Springer, Heidelberg, 2012: pp. 219-227.
69. Espinosa N, Wirth SH. Revision of the aseptic and septic total ankle replacement. Clin Podiatr Med Surg. 2013;30(2):171-185.
70. Fukuda T, Haddad SL, Ren Y, Zhang L-Q. Impact of talar component rotation on contact pressure after total ankle arthroplasty: A cadaveric study. Foot Ankle Int. 2010;31(5):404-411.
71. Gaden MT, Ollivere BJ. Periprosthetic aseptic osteolysis in total ankle replacement: Cause and management. Clin Podiatr Med Surg. 2013;30(2):145-155.
72. Hanna RS, Haddad SL, Lazarus ML. Evaluation of periprosthetic lucency after total ankle arthroplasty: Helical CT versus conventional radiography. Foot Ankle Int. 2007;28(8):921-926.
73. Ingham E, Fisher J. Biological reactions to wear debris in total joint replacement. Proc Instn Mech Engrs. 2000;214: Part H:21-37.
74. Kohonen I, Koivu H, Pudas T, et al. Does computed tomography add information on radiographic analysis in detecting periprosthetic osteolysis after total ankle arthroplasty? Foot Ankle Int. 2013;34(2):180-188.
75. Kobayashi A, Minoda Y, Kadoya Y, et al. Ankle arthroplasties generate wear particles similar to knee arthroplasties. Clin Orthop. 2004;424:69-72.
76. Nicholson JJ, Parks BG, Stroud C, et al. Joint contact characteristics in Agility total ankle arthroplasty. Clin Orthop Rel Res. 2004;424:125-129.
77. Rippstein PF, Huber M, Naal FD. Management of specific complications related to total ankle arthroplasty. Foot Ankle Clin. 2012;17(4):707-717.
78. Smith TW, Stephens M. Ankle arthroplasty. Foot Ankle Surg. 2010;16(2):53.
79. Vaupel Z, Baker EA, Baker KC, et al. Analysis of retrieved Agility™ total ankle arthroplasty systems. Foot Ankle Int. 2009;30(9):815-823.
80. Dunbar M, Glazebrook M. Diagnosis and classification of bone defects: The effect on total ankle arthroplasty, In: Coetzee JC, Hurwitz SR (eds): Arthritis & Arthroplasty: the Foot and Ankle, Ch. 19, Saunders Elsevier, Philadelphia, 2010; pp. 171-177.
81. Abicht BP, Roukis TS. The INBONE™ II total ankle replacement system. Clin Podiatr Med Surg. 2013;30(1):47-68.
82. DeVries JG, Scott RT, Berlet GC, et al. Agility™ to INBONE™:Anterior and posterior approaches to the difficult revision total ankle replacement. Clin Podiatr Med Surg. 2013;30(1):81-96.
83. Meeker J, Wegner N, Francisco R, et al. Revision techniques in total ankle arthroplasty utilizing a stemmed tibial arthroplasty system. Tec Foot Ankle. 2013;12:99-108.
84. DeOrio JK. Revision INBONE™ total ankle replacement. Clin Pod Med Surg. 2013;30(2):225-236.
85. Donnenwerth M, Roukis TS. Tibio-talo-calcaneal arthrodesis with retrograde intramedullary compression nail fixation for salvage of failed total ankle replacement: A systematic review. Clin Podiatr Med Surg. 2013;30(2):199-206.
86. Penner MJ. Failed ankle replacement and conversion to arthrodesis: a treatment algorithm. Tec Foot Ankle. 2012;11:125-132.
87. Ellington K, Myerson MS. Outcomes following revision total ankle replacement. Poster #5. Presented at the American Orthopaedic Foot and Ankle Society Annual Summer Meeting, Keystone, CO 14-16 July 2011. Available at: www.aofas.org/education/annual-meeting/Documents/2011_e-Poster-Abstracts.pdf Accessed August 2, 2013.
88. Myerson MS, Christensen JC, Steck JK, et al. Roundtable discussion: Avascular necrosis of the foot and ankle. Foot Ankle Spec. 2012;5(2):128-136.
89. Pappas MJ, Buechel Sr FF. Failure modes of current total ankle replacement systems. Clin Podiatr Med Surg. 2013;30(2):123-143.
90. Roukis TS, Prissel MA. Management of extensive talar osteolysis with the Agility™ total ankle replacement systems using geometric metal-reinforced polymethylmethacrylate cement augmentation. J Foot Ankle Surg. 2014;53(1):108-13.
91. Roukis TS. Modified Evans peroneus brevis lateral ankle stabilization for balancing varus ankle contracture during total ankle replacement. J Foot Ankle Surg. 2013;52(6):789-792.
92. Roukis TS. Tibialis posterior recession for balancing varus ankle contracture during total ankle replacement. J Foot Ankle Surg. 2013;52(5):686-689.
93. Ferrao P, Myerson MS., Schuberth JM, et al. Cement spacer as definitive management for postoperative ankle infection. Foot Ankle Int. 2012;33(3):173-178.