- Email: [email protected]
The present state of ankle arthroplasty
Available online at www.sciencedirect.com
Foot and Ankle Surgery 14 (2008) 115–119 www.elsevier.com/locate/fas
The present state of ankle arthroplasty Peter L.R. Wood MBBS FRCS*, Timothy M. Clough BSc Hons MB ChB FRCS Tr & Orth, Robert Smith MB ChB FRCS Eng Tr & Orth Wrightington Hospital, Wigan WN6 9EP, UK
Abstract Background: Total ankle arthroplasty (TAA) is being carried out with increasing frequency and manufacturers are releasing new implant designs each year. Methods: We comment on the various designs and the outcome of the procedure as reported in the literature. No results have so far been published on the majority of the more recent designs and where outcome data are available, the follow up period is very short. Results: For those designs where 5 or 10 year follow-up studies have been performed, the survivorship at 5 years is over 90% in most instances and of the order of 80% at 10 years. The failure rate is lower in ankles that are well aligned at presentation than it is for those with more than 15 degrees varus or valgus deformity pre-operatively. Conclusions: TAA has definite advantages over fusion for some patients and if selection criteria are adhered to, a long-lasting satisfactory outcome can be achieved. # 2008 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. Keywords: Total ankle replacement; Ankle; Arthroplasty; TAA; Arthritis
1. Introduction
2. Currently available designs
Three independent joint arthroplasty registers from Sweden, Norway and New Zealand have recently reported outcomes of total ankle arthroplasty (TAA) [1–3]. These reports describe 990 TAAs, adding significantly to the total number reported in the literature over the last 10 years and it is notable that the surgeons involved were not the designers of the prosthesis. The outcome of ankle replacement has greatly improved since the 1970s and 1980s and arguably the opinion expressed by Hamblen in 1985, i.e. the ankle could not be replaced, is no longer valid [4–6]. However the results still fall short of those being achieved for total knee arthroplasty [7]. Two systematic reviews of TAA, carried out over the last 5 years, conclude that replacement may now be an alternative to fusion for some patients with painful endstage arthritis of the ankle but further studies are still needed to demonstrate this conclusively [8,9].
Two mobile-bearing designs were developed in the 1980s. One was the Buechel–Pappas (BP) (Endotec, New Jersey, USA) (Fig. 1) and the other the Scandinavian Total Ankle Replacement (STAR) (Waldemar Link, Hamburg, Germany) (Fig. 2). These designs have been widely used in Europe but only on a restricted basis in the USA because of the Food and Drug Administration (FDA) regulatory controls. Buechel et al. and Kofoed reported similar longterm results of approximately 90% at 10 years using survivorship of the implant as an end-point [10,11]. However other surgeons have reported rather higher failure rates [12–14]. The general principle of the three-component, meniscal-bearing design is to keep the shear forces low by having minimum constraint and to reduce polyethylene wear by having maximum congruency between articular surfaces. In Europe more prostheses of this type have become available, for example, the SaltoTM (Tornier, Grenoble, France), Hintegra1 (Integra, France), Ankle Evolutive System (AES) (Biomet Europe, Belgium) Bologna-Oxford (BOX) (Finsbury, Leatherhead, UK) and Mobility (DePuy
* Corresponding author. E-mail address: [email protected] (P.L.R. Wood).
1268-7731/$ – see front matter # 2008 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.fas.2008.05.008
116
P.L.R. Wood et al. / Foot and Ankle Surgery 14 (2008) 115–119
procedure. Also it has been found that if the fusion does not become solid the failure rate is increased [15,17]. Over the last few years, three fixed-bearing designs have been approved for use in the USA by the FDA under 510(k) notification, i.e. that they are ‘‘substantially equivalent’’ to a previously marketed device. These are the Eclipse Total Ankle Implant (Integra [formerly Kinetikos Medical Inc.], USA), the Inbone (INBONE Technologies Inc., Berkeley, CA, USA), and the Salto Talaris (Tornier, Saint Ismier, France). There are no reports, as yet, of the clinical results for these prostheses. At present the use of mobile-bearing designs in the USA is restricted to investigational studies. However, in April 2007, the FDA granted the STAR ‘‘Approval with Conditions’’ and it may come into general use in the USA in the future. In Canada, New Zealand and Australia both fixed- and mobile-bearing devices are used.
3. Indications for total ankle arthroplasty
Fig. 1. Buechel–Pappas prosthesis (a) and (b).
Inc., Leeds, UK). These design changes are intended to make the surgical technique more reliable and make the prosthesis itself more anatomical in either shape or axis of movement. However only early results are available from the developers themselves and whether these design changes produce long-term benefits will require further study. The choice of prosthesis therefore rests with the surgeon who wants well designed jigs in order to make accurate bony resections and most importantly, to be confident that the remaining bony bed will securely support the implant. In the USA the situation has been influenced by the FDA regulations regarding the release of medical devices. Until recently the only replacement licensed for general use was the Agility (DePuy Orthopedics, Warsaw, IN, USA) (Fig. 3) and only then with cement fixation. By common practice the use of cement has been abandoned. The Agility is a fixedbearing device developed in the 1980s by Dr Frank Alvine. The published data by Knecht et al., reported a 10-year survivorship of 75% (95% CI 55–95) [15]. This outcome is very similar to that for 200 STAR replacements carried out in our centre where the 10-year survivorship was 80% (95% CI 71–90) [16]. The concern expressed by many surgeons about the Agility is that it requires large bony resections and the proximal component spans the syndosmosis, which must therefore be fused. This adds to the complexity of the
It is ill advised to suggest that replacement is more suitable than fusion for all patients with end-stage arthritis whether post-traumatic, idiopathic or inflammatory in origin. In many cases fusion will remain the best choice. Who are the patients for whom TAA offers an advantage over fusion? The brief answer is the middle aged or elderly patient with an anatomically aligned ankle and heel, whose ankle has a well-preserved range of movement that includes at least 5 degrees of dorsiflexion. Caution should be exercised in recommending replacement to a vigorously active patient in whom it may fail early. However some patients have an overwhelming desire to keep the ankle mobile and will choose replacement in full knowledge that further major surgery will almost certainly be required at some time in the future. Even if all goes well in the initial period, this may unfortunately happen within a few years. Early failure has been shown to be more frequent when there is a varus or valgus deformity preoperatively. The cautious surgeon will therefore not undertake replacement when the deformity is greater than 15 degrees [13,14,18,19]. It has been found that TAA does not increase the range of movement but rather preserves the amount that was present preoperatively [14,20]. It follows therefore that replacement might not be the best choice for a patient with a very stiff ankle, such as the case after a severe fracture or multiple operations. Here fusion may be a wiser choice provided that the subtalar and midtarsal joints are not also very stiff. The reason being that the outcome of surgery will be very similar whether a fusion or replacement is performed and replacement carries a higher risk of complication [21]. Perhaps a more important factor in making the choice between TAA and fusion is not simply the total range of movement but whether or not the ankle will dorsiflex to a neutral position. A severe equinus deformity cannot always be corrected by TAA even when full posterior releases are carried out. We have found that an ankle fused in an
P.L.R. Wood et al. / Foot and Ankle Surgery 14 (2008) 115–119
117
Fig. 2. Star prosthesis (a), (b), (c), and (d).
anatomical position gives a better gait than a replacement that will not dorsiflex. The patient with rheumatoid arthritis (RA) presents particular and rather different problems when compared with the patient with post-traumatic arthritis. Severe vascular or soft tissue problems might make any surgery to the ankle hazardous but provided there are no such contraindications, replacement is generally the preferred option. This is because replacement imposes less stress on the joints of the hindfoot, the function of which is already usually severely affected by the rheumatoid disease. The activities of a patient with RA will usually remain limited due to the polyarticular and systemic nature of the condition, even allowing for the great improvements in medical and surgical treatment in recent years. It is therefore the extent of
the arthritis in other joints rather than the patient’s age that must be considered when deciding between fusion and replacement. Notwithstanding the general desirability of a replacement, it may be impossible to carry out a TAA because there is inadequate bony support for the prosthesis due to large areas of collapse or massive cysts that breach the cortex. This is one such situation where fusion is obligatory but perhaps a more frequent contraindication is a severe valgus deformity, which is sometimes associated with a stress fracture of the fibula and incompetence of the deltoid ligament. It is generally considered that an intact medial ligament is a prerequisite to successful TAA. The rheumatoid ankle is different from the osteoarthritic ankle as the rest of the foot may also be very stiff. Replacement should therefore be considered because, even if the
118
P.L.R. Wood et al. / Foot and Ankle Surgery 14 (2008) 115–119
Fig. 3. Agility prosthesis.
postoperative movement is quite limited, this is still of great benefit to the rheumatoid patient. This is provided that the ankle dorsiflexes to a neutral position. The reason for this is that during walking, a rigid ankle and foot increases the loading of the forefoot, thus aggravating metatarsalgia. It also imposes severe strain on the knee joint.
4. Surgical comments Almost without exception TAA is performed through an anterior surgical approach passing between tibialis anterior and extensor hallucis longus tendons and retracting the neurovascular bundle laterally. Unlike in the knee and hip, the ankle cannot be fully dislocated in order to gain full exposure of the joint surfaces and a direct view of the lateral and medial sides of the joint is blocked by the malleoli. These factors probably are responsible for the frequent complication of malleolar fracture and the high incidence of poor wound healing may be due to the skin edges being forcefully retracted in an attempt to improve access to the joint [22]. Tragically, on rare occasions the final outcome of severe complications is a painful, infected or flail ankle for which the only treatment is amputation. As expected these complications become much less frequent with experience and they should become less frequent when TAA becomes part of standard orthopaedic surgical training [1,23,24].
5. Revision procedures Without any doubt, TAA is now being performed more frequently and in more countries compared with 10 years
ago. Consequently the numbers of patients in whom the replacement fails will also increase. The malleoli that frustrate the surgeon by limiting exposure at the time of surgery can, on occasions, save a patient from the need for further surgery. This is because as the components subside, loading shifts from the prosthesis to the contact area between the malleoli and talus. In a low demand patient, this may cause only mild symptoms, so long as the heel remains well aligned. This is the so-called safe failure described by Cooke [25]. This is by no means always the case as further surgery is often needed. If the problem leading to failure can be corrected, for example malaligned components, and there is sufficient remaining bone stock, then revisional replacement is an option. However one should not leave the patient in a situation where amputation would be the only option should the procedure fail in either the early or long term. For this reason we and others favour fusion as the revision procedure of choice in most circumstances [26,27]. Where there is good bone and soft tissues, the use of large bone grafts to fill the cavity, combined with rigid internal fixation, preserves length and leaves the subtalar joint intact [28]. The use of a large bone graft can be avoided if so wished but a degree of shortening will be inevitable. When the whole talar body is destroyed or the subtalar joint ankylosed, tibio talar calcaneal fusion with an intramedullary nail has been found to be quite reliable [29].
6. Conclusions Modern TAAs are succeeding in improving pain, and in maintaining the movement of arthritic ankles due to either osteoarthritis or RA. In our opinion TAA is often preferable to fusion for many patients provided they accept the possibility that further surgery may be needed in the future. However, we believe that fusion remains the safer and more reliable treatment for malaligned ankles and for osteoarthritic ankles that have lost almost all movement, especially where there is an equinus deformity.
References ˚ . The Swedish Ankle Arthroplasty [1] Henricson A, Skoog A, Carlsson A Register: an analysis of 531 arthroplasties between 1993 and 2005. Acta Orthop 2007;78:569–74. [2] Fevang B-TS, Lie SA, Havelin LI, Brun JG, Skredderstuen A, Furnes O. 257 ankle arthroplasties performed in Norway between 1994 and 2005. Acta Orthop 2007;78:575–83. [3] Hosman AH, Mason RB, Hobbs T, Rothwell AG. A New Zealand national joint registry review of 202 total ankle replacements followed for up to 6 years. Acta Orthop 2007;78:584–91. [4] Kitaoka HB, Patzer G. Clinical results of the Mayo Total Ankle Arthroplasty. J Bone Joint Surg Am 1996;78A:1658–64. [5] Bolton-Maggs BG, Sudlow RA, Freeman MAR. Total ankle arthroplasty: a long term view of the London Hospital Experience. J Bone Joint Surg Br 1985;67:785–90.
P.L.R. Wood et al. / Foot and Ankle Surgery 14 (2008) 115–119 [6] Hamblen DL. Can the ankle joint be replaced? J Bone Joint Surg Br 1985;67:689–90. [7] Baker PN, Khaw FM, Kirk LM, Esler CN, Gregg PJ. A randomised controlled trial of cemented versus cementless press-fit condylar total knee replacement: 15-year survival analysis. J Bone Joint Surg Br 2007;89:1608–14. [8] Stengel D, Bauwens K, Ekkernkamp A, Cramer J. Efficacy of total ankle replacement with meniscal-bearing devices: a systematic review and meta-analysis. Acta Orthop Trauma Surg 2005;125:109–19. [9] Haddad SL, Coetzee JC, Estok R, Fahrbach K, Banel D, Nalysnyk L. Intermediate and long-term outcomes of total ankle arthroplasty and ankle arthrodesis. A systematic review of the literature. J Bone Joint Surg Am 2007;89(9):1899–905. [10] Kofoed H. Scandinavian total ankle replacement (STAR). Clin Orthop Relat Res 2004;424:73–9. [11] Buechel Sr FF, Buechel Jr FF, Pappas MJ. Twenty-year evaluation of cementless mobile-bearing total ankle replacements. Clin Orthop Relat Res 2004;424:19–26. [12] Anderson T, Montgomery F, Carlsson A. Uncemented STAR total ankle prostheses. Three to eight-year follow-up of fifty-one consecutive ankles. J Bone Joint Surg Am 2003;85-A(7):1321–9. [13] Henricson A, Agren P. Secondary surgery after total ankle replacement. The influence of preoperative hindfoot alignment. Foot Ankle Surg 2007;13:41–4. [14] Wood PLR, Deakin S. Total ankle replacement: the results of 200 ankles. J Bone Joint Surg Br 2003;85-B:334–41. [15] Knecht SI, Estin M, Callaghan JJ, Zimmerman MB, Alliman KJ, Alvine FG, et al. The agility total ankle arthroplasty seven to sixteen-year follow-up. J Bone Joint Surg Am 2004;86-A:1161– 71. [16] Wood PLR, Prem H, Sutton C. Total ankle replacement: medium term results in 200 STAR ankles. J Bone Joint Surg 2008;90:605–9.
119
[17] Pyevich MT, Saltzman CL, Callaghan JJ, Alvine FG, Pyevich MT, Saltzman CL, et al. Total ankle arthroplasty: a unique design. Two to twelve-year follow-up. J Bone Joint Surg Am 1998;80:1410–20. [18] Doets HC, Brand R, Nelissen RG. Total ankle arthroplasty in inflammatory joint disease with use of two mobile-bearing designs. J Bone Joint Surg Am 2006;88:1272–84. [19] Haskell A, Mann R. Ankle arthroplasty with preoperative coronal plane deformity. Short-term results. Clin Orthop Relat Res 2004;424:98–103. [20] Coetzee JC, Castro MD. Accurate measurement of ankle range of motion after total ankle arthroplasty. Clin Orthop Relat Res 2004;424:27–31. [21] SooHoo NF, Zingmond DS, Ko CY. Comparison of reoperation rates following ankle arthrodesis and total ankle arthroplasty. J Bone Joint Surg Am 2007;89:2143–9. [22] McGarvey WC, Clanton TO, Lundz D. Malleolar fracture after ankle arthroplasty. Clin Orthop Relat Res 2004;424:104–10. [23] Kumar A, Dhar S. Total ankle replacement: early results during learning period. Foot Ankle Surg 2007;13:19–23. [24] Haskell A, Mann R. Perioperative complication rate of total ankle replacement is reduced by surgeon experience. Foot Ankle Int 2004;283–9. [25] Cooke P. Personal communication. Oxford: Nuffield Orthopaedic Hospital; 2007. [26] Kotnis R, Pasapula C, Anwar F, Cooke PH, Sharp RJ. The management of failed ankle replacement. J Bone Joint Surg Br 2006;88:1039– 47. [27] Hopgood P, Kumar R, Wood PLR. Ankle arthrodesis for failed total ankle replacement. J Bone Joint Surg Br 2006;88:1032–8. [28] Culpan P, Le Strat V, Piriou P, Judet T. Arthrodesis after failed total ankle replacement. J Bone Joint Surg Br 2007;89:1178–83. [29] Carlsson AS, Montgomery F, Besjakov J. Arthrodesis of the ankle secondary to replacement. Foot Ankle Int 1998;19:240–5.
Foot and Ankle Surgery 14 (2008) 115–119 www.elsevier.com/locate/fas
The present state of ankle arthroplasty Peter L.R. Wood MBBS FRCS*, Timothy M. Clough BSc Hons MB ChB FRCS Tr & Orth, Robert Smith MB ChB FRCS Eng Tr & Orth Wrightington Hospital, Wigan WN6 9EP, UK
Abstract Background: Total ankle arthroplasty (TAA) is being carried out with increasing frequency and manufacturers are releasing new implant designs each year. Methods: We comment on the various designs and the outcome of the procedure as reported in the literature. No results have so far been published on the majority of the more recent designs and where outcome data are available, the follow up period is very short. Results: For those designs where 5 or 10 year follow-up studies have been performed, the survivorship at 5 years is over 90% in most instances and of the order of 80% at 10 years. The failure rate is lower in ankles that are well aligned at presentation than it is for those with more than 15 degrees varus or valgus deformity pre-operatively. Conclusions: TAA has definite advantages over fusion for some patients and if selection criteria are adhered to, a long-lasting satisfactory outcome can be achieved. # 2008 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. Keywords: Total ankle replacement; Ankle; Arthroplasty; TAA; Arthritis
1. Introduction
2. Currently available designs
Three independent joint arthroplasty registers from Sweden, Norway and New Zealand have recently reported outcomes of total ankle arthroplasty (TAA) [1–3]. These reports describe 990 TAAs, adding significantly to the total number reported in the literature over the last 10 years and it is notable that the surgeons involved were not the designers of the prosthesis. The outcome of ankle replacement has greatly improved since the 1970s and 1980s and arguably the opinion expressed by Hamblen in 1985, i.e. the ankle could not be replaced, is no longer valid [4–6]. However the results still fall short of those being achieved for total knee arthroplasty [7]. Two systematic reviews of TAA, carried out over the last 5 years, conclude that replacement may now be an alternative to fusion for some patients with painful endstage arthritis of the ankle but further studies are still needed to demonstrate this conclusively [8,9].
Two mobile-bearing designs were developed in the 1980s. One was the Buechel–Pappas (BP) (Endotec, New Jersey, USA) (Fig. 1) and the other the Scandinavian Total Ankle Replacement (STAR) (Waldemar Link, Hamburg, Germany) (Fig. 2). These designs have been widely used in Europe but only on a restricted basis in the USA because of the Food and Drug Administration (FDA) regulatory controls. Buechel et al. and Kofoed reported similar longterm results of approximately 90% at 10 years using survivorship of the implant as an end-point [10,11]. However other surgeons have reported rather higher failure rates [12–14]. The general principle of the three-component, meniscal-bearing design is to keep the shear forces low by having minimum constraint and to reduce polyethylene wear by having maximum congruency between articular surfaces. In Europe more prostheses of this type have become available, for example, the SaltoTM (Tornier, Grenoble, France), Hintegra1 (Integra, France), Ankle Evolutive System (AES) (Biomet Europe, Belgium) Bologna-Oxford (BOX) (Finsbury, Leatherhead, UK) and Mobility (DePuy
* Corresponding author. E-mail address: [email protected] (P.L.R. Wood).
1268-7731/$ – see front matter # 2008 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.fas.2008.05.008
116
P.L.R. Wood et al. / Foot and Ankle Surgery 14 (2008) 115–119
procedure. Also it has been found that if the fusion does not become solid the failure rate is increased [15,17]. Over the last few years, three fixed-bearing designs have been approved for use in the USA by the FDA under 510(k) notification, i.e. that they are ‘‘substantially equivalent’’ to a previously marketed device. These are the Eclipse Total Ankle Implant (Integra [formerly Kinetikos Medical Inc.], USA), the Inbone (INBONE Technologies Inc., Berkeley, CA, USA), and the Salto Talaris (Tornier, Saint Ismier, France). There are no reports, as yet, of the clinical results for these prostheses. At present the use of mobile-bearing designs in the USA is restricted to investigational studies. However, in April 2007, the FDA granted the STAR ‘‘Approval with Conditions’’ and it may come into general use in the USA in the future. In Canada, New Zealand and Australia both fixed- and mobile-bearing devices are used.
3. Indications for total ankle arthroplasty
Fig. 1. Buechel–Pappas prosthesis (a) and (b).
Inc., Leeds, UK). These design changes are intended to make the surgical technique more reliable and make the prosthesis itself more anatomical in either shape or axis of movement. However only early results are available from the developers themselves and whether these design changes produce long-term benefits will require further study. The choice of prosthesis therefore rests with the surgeon who wants well designed jigs in order to make accurate bony resections and most importantly, to be confident that the remaining bony bed will securely support the implant. In the USA the situation has been influenced by the FDA regulations regarding the release of medical devices. Until recently the only replacement licensed for general use was the Agility (DePuy Orthopedics, Warsaw, IN, USA) (Fig. 3) and only then with cement fixation. By common practice the use of cement has been abandoned. The Agility is a fixedbearing device developed in the 1980s by Dr Frank Alvine. The published data by Knecht et al., reported a 10-year survivorship of 75% (95% CI 55–95) [15]. This outcome is very similar to that for 200 STAR replacements carried out in our centre where the 10-year survivorship was 80% (95% CI 71–90) [16]. The concern expressed by many surgeons about the Agility is that it requires large bony resections and the proximal component spans the syndosmosis, which must therefore be fused. This adds to the complexity of the
It is ill advised to suggest that replacement is more suitable than fusion for all patients with end-stage arthritis whether post-traumatic, idiopathic or inflammatory in origin. In many cases fusion will remain the best choice. Who are the patients for whom TAA offers an advantage over fusion? The brief answer is the middle aged or elderly patient with an anatomically aligned ankle and heel, whose ankle has a well-preserved range of movement that includes at least 5 degrees of dorsiflexion. Caution should be exercised in recommending replacement to a vigorously active patient in whom it may fail early. However some patients have an overwhelming desire to keep the ankle mobile and will choose replacement in full knowledge that further major surgery will almost certainly be required at some time in the future. Even if all goes well in the initial period, this may unfortunately happen within a few years. Early failure has been shown to be more frequent when there is a varus or valgus deformity preoperatively. The cautious surgeon will therefore not undertake replacement when the deformity is greater than 15 degrees [13,14,18,19]. It has been found that TAA does not increase the range of movement but rather preserves the amount that was present preoperatively [14,20]. It follows therefore that replacement might not be the best choice for a patient with a very stiff ankle, such as the case after a severe fracture or multiple operations. Here fusion may be a wiser choice provided that the subtalar and midtarsal joints are not also very stiff. The reason being that the outcome of surgery will be very similar whether a fusion or replacement is performed and replacement carries a higher risk of complication [21]. Perhaps a more important factor in making the choice between TAA and fusion is not simply the total range of movement but whether or not the ankle will dorsiflex to a neutral position. A severe equinus deformity cannot always be corrected by TAA even when full posterior releases are carried out. We have found that an ankle fused in an
P.L.R. Wood et al. / Foot and Ankle Surgery 14 (2008) 115–119
117
Fig. 2. Star prosthesis (a), (b), (c), and (d).
anatomical position gives a better gait than a replacement that will not dorsiflex. The patient with rheumatoid arthritis (RA) presents particular and rather different problems when compared with the patient with post-traumatic arthritis. Severe vascular or soft tissue problems might make any surgery to the ankle hazardous but provided there are no such contraindications, replacement is generally the preferred option. This is because replacement imposes less stress on the joints of the hindfoot, the function of which is already usually severely affected by the rheumatoid disease. The activities of a patient with RA will usually remain limited due to the polyarticular and systemic nature of the condition, even allowing for the great improvements in medical and surgical treatment in recent years. It is therefore the extent of
the arthritis in other joints rather than the patient’s age that must be considered when deciding between fusion and replacement. Notwithstanding the general desirability of a replacement, it may be impossible to carry out a TAA because there is inadequate bony support for the prosthesis due to large areas of collapse or massive cysts that breach the cortex. This is one such situation where fusion is obligatory but perhaps a more frequent contraindication is a severe valgus deformity, which is sometimes associated with a stress fracture of the fibula and incompetence of the deltoid ligament. It is generally considered that an intact medial ligament is a prerequisite to successful TAA. The rheumatoid ankle is different from the osteoarthritic ankle as the rest of the foot may also be very stiff. Replacement should therefore be considered because, even if the
118
P.L.R. Wood et al. / Foot and Ankle Surgery 14 (2008) 115–119
Fig. 3. Agility prosthesis.
postoperative movement is quite limited, this is still of great benefit to the rheumatoid patient. This is provided that the ankle dorsiflexes to a neutral position. The reason for this is that during walking, a rigid ankle and foot increases the loading of the forefoot, thus aggravating metatarsalgia. It also imposes severe strain on the knee joint.
4. Surgical comments Almost without exception TAA is performed through an anterior surgical approach passing between tibialis anterior and extensor hallucis longus tendons and retracting the neurovascular bundle laterally. Unlike in the knee and hip, the ankle cannot be fully dislocated in order to gain full exposure of the joint surfaces and a direct view of the lateral and medial sides of the joint is blocked by the malleoli. These factors probably are responsible for the frequent complication of malleolar fracture and the high incidence of poor wound healing may be due to the skin edges being forcefully retracted in an attempt to improve access to the joint [22]. Tragically, on rare occasions the final outcome of severe complications is a painful, infected or flail ankle for which the only treatment is amputation. As expected these complications become much less frequent with experience and they should become less frequent when TAA becomes part of standard orthopaedic surgical training [1,23,24].
5. Revision procedures Without any doubt, TAA is now being performed more frequently and in more countries compared with 10 years
ago. Consequently the numbers of patients in whom the replacement fails will also increase. The malleoli that frustrate the surgeon by limiting exposure at the time of surgery can, on occasions, save a patient from the need for further surgery. This is because as the components subside, loading shifts from the prosthesis to the contact area between the malleoli and talus. In a low demand patient, this may cause only mild symptoms, so long as the heel remains well aligned. This is the so-called safe failure described by Cooke [25]. This is by no means always the case as further surgery is often needed. If the problem leading to failure can be corrected, for example malaligned components, and there is sufficient remaining bone stock, then revisional replacement is an option. However one should not leave the patient in a situation where amputation would be the only option should the procedure fail in either the early or long term. For this reason we and others favour fusion as the revision procedure of choice in most circumstances [26,27]. Where there is good bone and soft tissues, the use of large bone grafts to fill the cavity, combined with rigid internal fixation, preserves length and leaves the subtalar joint intact [28]. The use of a large bone graft can be avoided if so wished but a degree of shortening will be inevitable. When the whole talar body is destroyed or the subtalar joint ankylosed, tibio talar calcaneal fusion with an intramedullary nail has been found to be quite reliable [29].
6. Conclusions Modern TAAs are succeeding in improving pain, and in maintaining the movement of arthritic ankles due to either osteoarthritis or RA. In our opinion TAA is often preferable to fusion for many patients provided they accept the possibility that further surgery may be needed in the future. However, we believe that fusion remains the safer and more reliable treatment for malaligned ankles and for osteoarthritic ankles that have lost almost all movement, especially where there is an equinus deformity.
References ˚ . The Swedish Ankle Arthroplasty [1] Henricson A, Skoog A, Carlsson A Register: an analysis of 531 arthroplasties between 1993 and 2005. Acta Orthop 2007;78:569–74. [2] Fevang B-TS, Lie SA, Havelin LI, Brun JG, Skredderstuen A, Furnes O. 257 ankle arthroplasties performed in Norway between 1994 and 2005. Acta Orthop 2007;78:575–83. [3] Hosman AH, Mason RB, Hobbs T, Rothwell AG. A New Zealand national joint registry review of 202 total ankle replacements followed for up to 6 years. Acta Orthop 2007;78:584–91. [4] Kitaoka HB, Patzer G. Clinical results of the Mayo Total Ankle Arthroplasty. J Bone Joint Surg Am 1996;78A:1658–64. [5] Bolton-Maggs BG, Sudlow RA, Freeman MAR. Total ankle arthroplasty: a long term view of the London Hospital Experience. J Bone Joint Surg Br 1985;67:785–90.
P.L.R. Wood et al. / Foot and Ankle Surgery 14 (2008) 115–119 [6] Hamblen DL. Can the ankle joint be replaced? J Bone Joint Surg Br 1985;67:689–90. [7] Baker PN, Khaw FM, Kirk LM, Esler CN, Gregg PJ. A randomised controlled trial of cemented versus cementless press-fit condylar total knee replacement: 15-year survival analysis. J Bone Joint Surg Br 2007;89:1608–14. [8] Stengel D, Bauwens K, Ekkernkamp A, Cramer J. Efficacy of total ankle replacement with meniscal-bearing devices: a systematic review and meta-analysis. Acta Orthop Trauma Surg 2005;125:109–19. [9] Haddad SL, Coetzee JC, Estok R, Fahrbach K, Banel D, Nalysnyk L. Intermediate and long-term outcomes of total ankle arthroplasty and ankle arthrodesis. A systematic review of the literature. J Bone Joint Surg Am 2007;89(9):1899–905. [10] Kofoed H. Scandinavian total ankle replacement (STAR). Clin Orthop Relat Res 2004;424:73–9. [11] Buechel Sr FF, Buechel Jr FF, Pappas MJ. Twenty-year evaluation of cementless mobile-bearing total ankle replacements. Clin Orthop Relat Res 2004;424:19–26. [12] Anderson T, Montgomery F, Carlsson A. Uncemented STAR total ankle prostheses. Three to eight-year follow-up of fifty-one consecutive ankles. J Bone Joint Surg Am 2003;85-A(7):1321–9. [13] Henricson A, Agren P. Secondary surgery after total ankle replacement. The influence of preoperative hindfoot alignment. Foot Ankle Surg 2007;13:41–4. [14] Wood PLR, Deakin S. Total ankle replacement: the results of 200 ankles. J Bone Joint Surg Br 2003;85-B:334–41. [15] Knecht SI, Estin M, Callaghan JJ, Zimmerman MB, Alliman KJ, Alvine FG, et al. The agility total ankle arthroplasty seven to sixteen-year follow-up. J Bone Joint Surg Am 2004;86-A:1161– 71. [16] Wood PLR, Prem H, Sutton C. Total ankle replacement: medium term results in 200 STAR ankles. J Bone Joint Surg 2008;90:605–9.
119
[17] Pyevich MT, Saltzman CL, Callaghan JJ, Alvine FG, Pyevich MT, Saltzman CL, et al. Total ankle arthroplasty: a unique design. Two to twelve-year follow-up. J Bone Joint Surg Am 1998;80:1410–20. [18] Doets HC, Brand R, Nelissen RG. Total ankle arthroplasty in inflammatory joint disease with use of two mobile-bearing designs. J Bone Joint Surg Am 2006;88:1272–84. [19] Haskell A, Mann R. Ankle arthroplasty with preoperative coronal plane deformity. Short-term results. Clin Orthop Relat Res 2004;424:98–103. [20] Coetzee JC, Castro MD. Accurate measurement of ankle range of motion after total ankle arthroplasty. Clin Orthop Relat Res 2004;424:27–31. [21] SooHoo NF, Zingmond DS, Ko CY. Comparison of reoperation rates following ankle arthrodesis and total ankle arthroplasty. J Bone Joint Surg Am 2007;89:2143–9. [22] McGarvey WC, Clanton TO, Lundz D. Malleolar fracture after ankle arthroplasty. Clin Orthop Relat Res 2004;424:104–10. [23] Kumar A, Dhar S. Total ankle replacement: early results during learning period. Foot Ankle Surg 2007;13:19–23. [24] Haskell A, Mann R. Perioperative complication rate of total ankle replacement is reduced by surgeon experience. Foot Ankle Int 2004;283–9. [25] Cooke P. Personal communication. Oxford: Nuffield Orthopaedic Hospital; 2007. [26] Kotnis R, Pasapula C, Anwar F, Cooke PH, Sharp RJ. The management of failed ankle replacement. J Bone Joint Surg Br 2006;88:1039– 47. [27] Hopgood P, Kumar R, Wood PLR. Ankle arthrodesis for failed total ankle replacement. J Bone Joint Surg Br 2006;88:1032–8. [28] Culpan P, Le Strat V, Piriou P, Judet T. Arthrodesis after failed total ankle replacement. J Bone Joint Surg Br 2007;89:1178–83. [29] Carlsson AS, Montgomery F, Besjakov J. Arthrodesis of the ankle secondary to replacement. Foot Ankle Int 1998;19:240–5.