The Salto Total Ankle Arthroplasty: Survivorship and Analysis of Failures at 7 to 11 years

Michel Bonnin, MD,1 Fabrice Gaudot, MD,2 Jean-Raphael Laurent, MD,1 Scott Ellis, MD,3 Jean-Alain Colombier, MD,4and Thierry Judet, MD2

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Abstract

Background

Despite the appearance of new-generation, mobile-bearing, cementless prostheses, total ankle arthroplasty remains controversial. Among the criteria guiding the choice between arthrodesis and arthroplasty, the long-term survival and postoperative function are of critical importance. The mobile-bearing Salto prosthesis has been used in Europe since 1997, but only 2 to 5 years of followup data have been reported.

Questions/purposes

We analyzed the longer-term survivorship and causes of failures of the Salto prosthesis in a cohort of previously studied patients. We asked whether this prosthesis provided a functional ankle (AOFAS score) and durable radiographic fixation.

Patients and Methods

We retrospectively reviewed 96 prospectively followed patients with 98 prostheses implanted between 1997 and 2000. Of those, 85 patients (87 prostheses) had a minimum followup of 6.8 years (mean, 8.9 years; range, 6.8–11.1 years).

Results

The survival rate was 65% (95% CI, 50–80) with any reoperation of the ankle and 85% (95% CI, 75–95) with revision of a component as the end points. Six prostheses were removed for arthrodesis, and 18 ankles underwent reoperation without arthrodesis. We observed three main causes of reoperations: bone cysts (11 patients), fracture of the polyethylene (five patients), and unexplained pain (three patients). The mean AOFAS score was 79 ± 12 points. Radiographic subsidence was observed in three patients and bone cysts in eight patients.

Conclusions

Our data suggest a high rate of reoperations but only six revisions with arthrodesis with mid-term followup. We observed few patients with loosening and/or subsidence.

Level of Evidence

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

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Introduction

In patients with advanced arthrosis of the ankle, surgery most often is limited to arthrodesis and total ankle arthroplasty (TAA) with other options such as distraction arthroplasty [46, 50] and allograft transplantation [21, 22, 30] considered in select cases. Particularly in Europe, the appearance of new-generation, mobile-bearing, cementless prostheses has renewed interest in TAA [5, 11, 24, 33, 48,51–53]. The theoretical advantages of TAA compared with arthrodesis are maintaining joint ROM and restoring more normal kinematics in the hopes of providing the patient with greater comfort and better functional recovery [7, 31, 33, 35, 49]. The disadvantages are related to the risk of mechanical complications with failure sometimes requiring implant removal along with subsequent arthrodesis, which can be technically demanding and lead to a less satisfactory result than with primary arthrodesis [10, 19, 47].

Among the criteria guiding the choice between arthrodesis and arthroplasty, postoperative function and implant durability are particularly important. The main causes of TAA failure are implant loosening and/or migration, wear, fracture or dislocation of the mobile bearing, infection, unexplained pain, and the development of laxity [13, 15, 18, 20]. The development of osteolytic cysts has been reported in series of uncemented, mobile-bearing implants [3, 29, 48, 51–53], and Agility prostheses [26].

The Salto® prosthesis (Tornier SA, Saint Ismier, France) has a cementless, anatomic design with mobile-bearing polyethylene. It has been in use since January 1997. It is made of a cobalt-chrome alloy and coated with a layer of pure titanium (T40) and calcium hydroxyapatite. The first 98 Salto prostheses implanted between 1997 and 2000, previously investigated at a mean followup of 35 months as part of a multicenter prospective study, showed a 95% to 98% survivorship and a mean AOFAS score of 83.1 points [5].

The goals of our study were to analyze the survivorship and causes of failures of the Salto prosthesis from this first series of patients, at a longer-term followup of 7 to 11 years. We asked whether this prosthesis provides a functional ankle and durable radiologic fixation, with special attention to bone cysts.

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Patients and Methods

We prospectively followed 96 patients (98 ankles) in whom Salto prostheses were implanted between January 1997 and December 2000. Our indications for TAA were end-stage ankle osteoarthritis (OA) or rheumatoid arthritis (RA). Contraindications to perform TAA included active ankle infection and poor skin and soft tissue quality believed to increase the risk of postoperative necrosis. We did not consider substantial varus and valgus deformities as contraindications, but hindfoot deformities were corrected as a first step with an associated procedure (triple arthrodesis). During the same 4-year period, 24 arthrodeses were performed by the same three surgeons, all for posttraumatic OA. The initial diagnosis was posttraumatic OA in 43 patients (20 bimalleolar ankle fractures, 14 tibial pilon fractures, four talus fractures, and five fractures of the distal third of the tibia). Eight patients presented with OA secondary to chronic instability, whereas four patients who had a prior ankle infection had OA develop. The diagnosis of primary OA was made for 14 patients in whom no other identifiable cause could be found. For the purpose of analysis, the OA group consisted of these 69 patients. Their mean age was 57 years (range, 26–81 years) at the time of surgery. Twenty-seven patients with RA had a mean age of 54 years (range, 28–77 years). The mean delay between the diagnosis of RA and surgery was 17 years (range, 3–36 years). There were 60 females and 36 males with a mean age of 56 ± 13 years (range, 26–81 years). The patients’ mean weight was 66 ± 13 kg (range, 41–93 kg), height was 166 ± 8 cm (range, 152–183 cm), and body mass index was 24 kg/m2 (range, 18–28 kg/m2). Of the 96 patients undergoing TAA, nine died from unrelated reasons. None of these patients required reoperation. Two other patients were excluded from the final analysis; one patient underwent bilateral transtibial amputation 9 years after the TAA as a result of complications of Buerger’s disease (thromboangitis obliterans) but did not have any complications directly related to the ankle prosthesis and the other patient, a female farmer, sustained a crushing injury to the ankle with a cow’s hoof 1 year after the initial TAA, which led to major soft tissue loss and infection. Soft tissue healing was obtained after external fixation was performed using the Papineau technique to fuse the ankle [39]. The remaining 85 patients (87 prostheses) were followed for a minimum of 6.8 years (mean, 8.9 years; range, 6.8–11.1 years).

Eight patients had surgery on the ipsilateral forefoot and 18 had undergone a previous triple arthrodesis. Eighteen patients previously had either hip or knee arthroplasty before the TAA was performed: 13 THAs (eight ipsilateral), 12 TKAs (five ipsilateral), and seven patients with both.

Three surgeons (MB, JAC, TJ) performed all operations using a standardized technique [5, 6]. The goal was to restore a physiologic tibiocalcaneal axis and an anatomic joint line level. The tibial cut was made at 90° with a 7° posterior tibial slope after aligning the extramedullary guide with the anterior tibial crest. The amount of distal tibial resection was measured to match the metal tibial base plate plus the polyethylene insert. Special attention was paid to obtain proper rotation of the components, which were centered on the line bisecting the space between the medial and lateral talar facets. In patients with lateral ligament laxity, the medial deltoid was released from the tip of the medial malleolus. Ligamentous balance then was obtained by increasing the thickness of the polyethylene. The mean thickness of the mobile polyethylene insert was 4 mm (range, 3–6 mm). Thirty prostheses had a 3-mm polyethylene insert. In 20 patients in this series, a cemented lateral malleolar component was inserted [5]. It was progressively abandoned because it did not seem to improve the clinical results. At the end of the procedure, if dorsiflexion remained less than 5°, percutaneous lengthening of the Achilles tendon was performed (17% of cases in RA versus 45% in OA) [36].

Patients were immobilized with a cast with duration of casting depending on concomitant procedures performed and the condition of the soft tissues [5]. Weightbearing was permitted immediately, as tolerated, except in case of Achilles tendon lengthening, in which it was delayed for 3 weeks. After cast removal, nonaggressive self-rehabilitation based on weightbearing exercises, supervised by a physiotherapist, was begun. The mean delay before full weightbearing was 8 days (range, 1–31 days) and the mean duration of cast immobilization was 35 days (range, 5–45 days).

All patients were assessed with clinical and radiographic followups at 3 and 6 months, 1 year, and then every 2 years thereafter. Final scores were collected from the most recent followup for analysis. We assessed function using the AOFAS ankle-hindfoot score [25].

AP and lateral weightbearing radiographs of the ankle were taken preoperatively and at all followups. Two independent observers (FG, JRL) made measurements manually on the radiographs [1, 26, 37, 51] (Fig. 1). The accuracy of these radiographic measures has been assessed and a high level of intraobserver reliability has been reported [37]. Component migration, measured in relation to the immediate postoperative images, was defined as a change greater than 5° in the different measurements (Fig. 1). This criterion of 5° is based on previous reliability testing [37] and was recommended by Knecht et al. [26].

Fig. 1A–F

Weightbearing AP and lateral radiographs of the ankle were performed. A representative example is shown. On the AP view, the tibial angle (TA) was measured between the axis of the tibia and the articular surface of the tibial plafond (A) before and ( ...

To analyze osteolysis and lucencies, the distal tibia and the talus were divided into different zones on the radiographs (Fig. 2). A radiolucent line was considered pathologic if it was more than 2 mm thick or if it was observed globally across a prosthetic component [29, 48, 51]. An osteolytic cyst was defined as a hypodense zone greater than 5 mm in diameter with no inner bone trabeculae but with peripheral sclerosis that was not present preoperatively [3]. Radiographs were analyzed successively by the operators and by two independent surgeons (FG and JRL). In case of disagreement, the most unfavorable assessment was adopted [3]. In seven patients, bone cysts were already visible on the preoperative radiographs and were not considered pathologic (Figs. 3–4). A CT scan was performed routinely when cysts were observed on plain radiographs.

Fig. 2A–B

(A) AP and (B) lateral postoperative radiographs show the different zones of cysts for the tibial and talar components. On the AP view, the tibia is divided into seven zones (1 = medial malleolus, 2 = medial flange, 3 = medial ...

. 3A–D

In this patient with posttraumatic arthritis, bone cysts were observed preoperatively on (A) AP and (B) lateral radiographs and (C) AP and (D) lateral CT scans.

Fig. 4

Two years after implantation, the same cysts were still present in the same patient shown in Fig. 3. When bone cysts were observed preoperatively, as shown in this example, they were not included in the results.

Dynamic lateral weightbearing views with maximum dorsiflexion and plantar flexion were taken at each followup to determine the total ankle ROM using a previously described technique [5].

We analyzed the survivorship of the prosthesis using the Kaplan-Meier survivorship method [23]. A failure was defined as “any reoperation on the ankle” after implantation (revisions and reoperations) or as “removal or revision of any component, including exchange of polyethylene insert for fracture” (revisions) [17]. This last criterion is used frequently [9, 11, 23, 25, 27, 34, 39, 51]. Radiologic measurements and scores were compared using Student’s t test after checking the normal distribution of the samples with the Shapiro-Wilk test and the equality of variances with the F-test. All statistical analyses were performed with Minitab software (Version 14; Minitab Inc, State College, PA, USA).

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Results

The survival rate at 10 years followup with any reoperation on the ankle as the end point was 65% (95% confidence interval [CI], 50%–80%). It was 85% (95% CI, 75–95) when we used fusion or revision of any component as the criterion of failure (Fig. 5). Six implants in six patients, five in patients with OA and one in a patient with RA, were removed and converted to arthrodesis between 11 and 101 months after the initial intervention (mean delay, 54 ± 31 months) (Table 1) [10].

Fig. 5A–B

(A) The survival (Kaplan-Meier) calculated with end point reoperation of the ankle for any reason shows survival rates of 65% (95% confidence interval, 50%–80%) and (B) 85% (95% CI, 75–95) with end point fusion or revision of any component. ...

Table 1

Patients undergoing reoperation(s) in the current series

There were a total of 18 revisions without arthrodesis (Table 1). The polyethylene was exchanged secondary to fracture in five patients, between 72 and 122 months after the initial surgery (mean, 103 ± 19 months). This occurred only in patients in whom 3-mm polyethylene components were used. In one patient, concomitant revision of the tibial component was necessary owing to development of osteolysis (Fig. 6). Eight patients required reoperations for the development of symptomatic osteolytic cyst(s). The cysts were curetted and filled with cancellous autograft harvested from the ipsilateral iliac crest and the polyethylene was routinely exchanged. Histopathologic analyses of the curetted cysts revealed birefringent foreign bodies or metallic particles surrounded by a macrophage inflammatory reaction in all cases. The mean AOFAS score at last followup for these patients was 73.5 ± 12.5 (range, 52–90). Radiographs at last followup showed complete graft incorporation in four patients and residual cysts, all less than 5 mm diameter, in four patients. Five other patients underwent reoperations for various reasons: two submalleolar impingement, one loose lateral malleolar component, one synovial cyst, and one infection (Table 1).

Fig. 6A–D

(A) A fracture of the polyethylene occurred 8 years after implantation in the patient shown. The polyethylene was not revised until 6 months after the fracture occurred at which point concomitant revision of the tibial component was necessary ...

At last followup, the mean AOFAS ankle-hindfoot score was 79 ± 12, mean dorsiflexion was 9° ± 5°, and mean plantar flexion was 18° ± 8°. The mean tibial angle was 90° ± 2°, mean talar angle was 91° ± 2°, and mean tibial slope was 10° ± 4° (Tables 2 and ​and33).

Table 2

The AOFAS ankle-hindfoot scores (total possible 100 points) and range of motion*

Table 3

Radiologic results as measured preoperatively, postoperatively (6 months after surgery), and at last followup

Radiographic evidence of subsidence was observed on the tibia for one patient with RA, and on the talus for two patients (one with OA and one with RA). For the patient with RA, it was the result of the collapse of an autograft used at the index procedure to reconstruct severe bone loss in the talar body. None of these patients went on to revision because the functional results were satisfactory (AOFAS scores of 85, 76, and 85 points, respectively). Partial radiolucent lines were observed in numerous patients on the AP views (50 in Zone 2, eight in Zone 3, 25 in Zone 4, and one in Zone 5), but none of the patients had global radiolucencies. Bone cysts of 5 mm or larger were noted in four patients on the AP views of the tibia, involving five zones in one patient, three zones in two patients, and two zones in another patient, and in four other patients in the talus, involving three zones in one patient, two zones in one, and one zone in two. All were asymptomatic and four spontaneously regressed, as seen on radiographs, without modification in the patient’s activity (Fig. 7).

Fig. 7A–C

A case example is shown for a patient undergoing spontaneous regression of a bone cyst from (A) 1 year postoperatively to (B) 5 years postoperatively with a bone cyst in Zone 3 (arrow) to (C) 10 years postoperatively.

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Discussion

For patients with advanced arthritis of the ankle, surgery most often is limited to arthrodesis and TAA. Despite the appearance of new-generation, mobile-bearing, cementless prostheses, TAA remains controversial. Among the criteria guiding the choice between arthrodesis and arthroplasty, the long-term survival and postoperative function are of critical importance. The mobile-bearing Salto prosthesis has been used in Europe since 1997, but only 2 to 5 years of followup data have been reported [5]. The goals of our study were to analyze the survivorship and the causes of failures of the Salto prosthesis from this first series of patients, at a longer-term followup. We asked whether this prosthesis provides a functional ankle and durable radiologic fixation, with a special attention to bone cysts.

This study has several limitations. First, it is comprised of a series of patients operated on by the implant designers, including all the initial patients in the authors’ experience. The importance of the learning curve has been underscored by the Swedish registry, reporting a survival rate of 70% at 5 years for the first 30 implantations and 86% for ensuing patients [18]. Second, the functional results were assessed using only the AOFAS ankle-hindfoot score, which provides a limited analysis of function [34]. Third, the analysis of cysts was not performed systematically with CT scans, which theoretically could underestimate its incidence [16]. Fourth, the device and the technique have changed during the course of the study. In 2001, we extended the hydroxyapatite coating to the medial edge of the tibial component and after the first 20 patients, we no longer used the lateral malleolar implant. We also have abandoned the 3-mm polyethylene, which is the cause of five reoperations in this series. Finally, our survivorship analysis was based only on the patients who already had reoperations and not on the intention to treat. However, even if three patients had radiologic failures, no revisions for patients in this series are planned.

Survival often is difficult to assess from reported series of ankle prostheses as a result of various criteria of failure [13] (Tables 4, ​,5).5). In a recent meta-analysis, a 77% survival rate was reported at 10 years [15]. In a similar analysis, a 9.8% failure rate at a mean followup of 5.2 years with a survival rate varying from 67% at 6 years to 95.4% at 12 years were reported [13]. Data from the national registries are particularly interesting because of their exhaustive collection of outcomes. The Swedish registry reports a 62% survival rate at 10 years with fusion or revision as the end point [18]. The New Zealand registry reports a 5-year survival rate of 86% [20] and the Finnish registry reports a 7-year survival rate of 78% [42]. Despite our survival rate being similar to those reported in the literature, many revisions were required in this series of patients, reflecting our early experience.

Table 4

Causes of revisions of total ankle arthroplasty in different series in the literature

Table 5

Survivorship and clinical results in published series‡

Nineteen patients presented with tibial and/or talar bone cysts that were 5 mm or larger. Eight of these patients underwent a second operation with bone grafting, which subsequently did not evolve, whereas three went on to implant removal and fusion. An additional eight patients had bone cysts appearing on radiologic studies but remained asymptomatic. Some authors have reported similar findings with the Agility prosthesis [26, 37]. Tibial cysts with the STAR prosthesis have been reported in 3.5% of patients at 46 months and 17.5% at 88 months [51, 52]. The overall incidence of osteolytic cysts has been reported as 21% at 31 months [28] and 43% (talus) to 62% (tibia) at 40 months [3] for the AES prosthesis. The etiology of these bone cysts is poorly understood and likely multifactorial. Small nonprogressive cysts seem to be mechanical in nature and may occur in relation to a stress-shielding phenomena or bone remodeling in the distal tibia [26]. Large cysts seem to stem from chemical phenomena related to the release of wear particles. Three sources of particles theoretically can be involved: polyethylene, titanium, and hydroxyapatite [27, 29, 48]. In the current series, volumetric wear on the explanted inserts in patients who had revision surgery for osteolysis was not observed. The Food and Drug Administration (FDA) imposes strict fixation criteria for titanium coating [14]. In Europe, only the hydroxyapatite fixation layer is subject to such regulation. The titanium anchoring layer in the Salto prosthesis has satisfied the FDA criteria only since 2006. The role of hydroxyapatite has been debated [2, 4, 32, 38,43–45].

Osteolysis was observed in some patients in the current study particularly adjacent to the tibial keel, which is accessible to joint fluid and therefore wear debris. The observation from our experience corroborates the concept of effective joint space [41]. To isolate the keel of the joint space, we modified the surgical technique in 2003 by sealing off the anterior tibial window with bone graft after the tibia component was impacted in place. Since this change, it has not been necessary to perform secondary surgery to graft tibial cysts by any of the three surgeons in this study.

An important cause of revision was malleolar impingement and/or stiffness. A CT scan is now systematically ordered as part of the preoperative workup to ensure osteophytes and/or bone fragments are precisely located. Limitation in ankle dorsiflexion is tolerated particularly poorly, therefore requiring dorsiflexion of at least 10° be obtained at the end of surgery. When dorsiflexion is insufficient, an explanation should be sought: generally insufficient tibial resection or excessive anterior translation of the talar component. If no abnormality can be seen, a percutaneous Achilles lengthening or gastrocnemius recession should be performed.

In this first series of Salto prostheses, we found a high rate of reoperations but some subsequent potential failures likely have been eliminated through improvements in surgical technique and better patient selection. The stability of the prosthetic component fixation seems satisfactory with very few patients with loosening. This study highlights the importance of CT investigations to reveal cysts before and after replacement. Understanding the etiology of bone cysts should improve future results and deserves ongoing study.

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Footnotes

One or more authors (MB, JAC and TJ) received royalties from Tornier SA, Montbonnot, France.

Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research.

This work was performed at Centre Orthopédique Santy, Lyon, France.

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References

1. 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;85:1321–1329. [PubMed]

2. Bauer TW. Hydroxyapatite: coating controversies. Orthopedics. 1995;18:885–888. [PubMed]

3. Besse JL, Brito N, Lienhart C. Clinical evaluation and radiographic assessment of bone lysis of the AES total ankle replacement. Foot Ankle Int. 2009;30:964–975. doi: 10.3113/FAI.2009.0964. [PubMed][Cross Ref]

4. Bloebaum RD, Beeks D, Dorr LD, Savory CG, DuPont JA, Hofmann AA. Complications with hydroxyapatite particulate separation in total hip arthroplasty. Clin Orthop Relat Res. 1994;298:19–26.[PubMed]

5. Bonnin M, Judet T, Colombier JA, Buscayret F, Graveleau N, Piriou P. Midterm results of the Salto total ankle prosthesis. Clin Orthop Relat Res. 2004;424:6–18. doi: 10.1097/01.blo.0000132407.75881.a0. [PubMed] [Cross Ref]

6. Bonnin MP. [Total ankle arthroplasty] [in French]. Encycl Méd Chir Techniques chirurgicales – Orthopédie-Traumatologie.Editions Scientifiques et Médicales. Paris, France: Elsevier SAS; 2002;44–903.

7. Bonnin MP, Laurent JR, Casillas M. Ankle function and sports activity after total ankle arthroplasty.Foot Ankle Int. 2009;30:933–944. doi: 10.3113/FAI.2009.0933. [PubMed] [Cross Ref]

8. Buechel FF, Sr, Buechel FF, Jr, Pappas MJ. Eighteen-year evaluation of cementless meniscal bearing total ankle replacements. Instr Course Lect. 2002;51:143–151. [PubMed]

9. Buechel FF, Sr, Buechel FF, Jr, Pappas MJ. Twenty-year evaluation of cementless mobile-bearing total ankle replacements. Clin Orthop Relat Res. 2004;424:19–26. doi: 10.1097/01.blo.0000132243.41419.59. [PubMed] [Cross Ref]

10. Culpan P, Le Strat V, Piriou P, Judet T. Arthrodesis after failed total ankle replacement. J Bone Joint Surg Br. 2007;89:1178–1183. doi: 10.1302/0301-620X.89B9.19108. [PubMed] [Cross Ref]

11. 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;88:1272–1284. doi: 10.2106/JBJS.E.00414.[PubMed] [Cross Ref]

12. Domsic RT, Saltzman CL. Ankle osteoarthritis scale. Foot Ankle Int. 1998;19:466–471. [PubMed]

13. Gougoulias N, Khanna A, Maffulli N. How successful are current ankle replacements?: a systematic review of the literature. Clin Orthop Relat Res. 2010;468:199–208. doi: 10.1007/s11999-009-0987-3.[PMC free article] [PubMed] [Cross Ref]

14. Guidance for industry on the testing of metallic plasma sprayed coatings on orthopedic implants to support reconsideration of postmarket surveillance requirements. Available at:www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm107699.pdf. Accessed June 14, 2010.

15. 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;89:1899–1905. doi: 10.2106/JBJS.F.01149. [PubMed] [Cross Ref]

16. Hanna RS, Haddad SL, Lazarus ML. Evaluation of periprosthetic lucency after total ankle arthroplasty: helical CT versus conventional radiography. Foot Ankle Int. 2007;28:921–926. doi: 10.3113/FAI.2007.0921. [PubMed] [Cross Ref]

17. Henricson A, Carlsson A, Rydholm U. What is a revision of total ankle replacement? Foot Ankle Surg.2010; doi:10.1016/j.fas.2010.02.007. [PubMed]

18. Henricson A, Skoog A, Carlsson A. The Swedish Ankle Arthroplasty Register: an analysis of 531 arthroplasties between 1993 and 2005. Acta Orthop. 2007;78:569–574. doi: 10.1080/17453670710014248. [PubMed] [Cross Ref]

19. Hopgood P, Kumar R, Wood PL. Ankle arthrodesis for failed total ankle replacement. J Bone Joint Surg Br. 2006;88:1032–1038. doi: 10.1302/0301-620X.88B8.17627. [PubMed] [Cross Ref]

20. 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;78:584–591. doi: 10.1080/17453670710014266. [PubMed] [Cross Ref]

21. Jeng CL, Kadakia A, White KL, Myerson MS. Fresh osteochondral total ankle allograft transplantation for the treatment of ankle arthritis. Foot Ankle Int. 2008;29:554–560. doi: 10.3113/FAI.2008.0554. [PubMed] [Cross Ref]

22. Jeng CL, Myerson MS. Allograft total ankle replacement: a dead ringer to the natural joint. Foot Ankle Clin. 2008;13:539–547, x. [PubMed]

23. Kaplan EL, Meier P. Nonparameteric estimation from incomplete observations. J Am Stat Assoc.1958;53:457–481. doi: 10.2307/2281868. [Cross Ref]

24. Karantana A, Hobson S, Dhar S. The Scandinavian total ankle replacement: survivorship at 5 and 8 years comparable to other series. Clin Orthop Relat Res. 2010;468:951–957. doi: 10.1007/s11999-009-0971-y. [PMC free article] [PubMed] [Cross Ref]

25. Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS, Sanders M. Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int. 1994;15:349–353. [PubMed]

26. Knecht SI, Estin M, Callaghan JJ, Zimmerman MB, Alliman KJ, Alvine FG, Saltzman CL. The Agility total ankle arthroplasty: seven to sixteen-year follow-up. J Bone Joint Surg Am. 2004;86:1161–1171. [PubMed]

27. Kobayashi A, Minoda Y, Kadoya Y, Ohashi H, Takaoka K, Saltzman CL. Ankle arthroplasties generate wear particles similar to knee arthroplasties. Clin Orthop Relat Res. 2004;424:69–72. doi: 10.1097/01.blo.0000132182.54217.da. [PubMed] [Cross Ref]

28. Kofoed H. Scandinavian Total Ankle Replacement (STAR) Clin Orthop Relat Res. 2004;424:73–79. doi: 10.1097/01.blo.0000132414.41124.06. [PubMed] [Cross Ref]

29. Koivu H, Kohonen I, Sipola E, Alanen K, Vahlberg T, Tiusanen H. Severe periprosthetic osteolytic lesions after the ankle Evolutive system total ankle replacement. J Bone Joint Surg Br. 2009;91:907–914. doi: 10.1302/0301-620X.91B7.22434. [PubMed] [Cross Ref]

30. Lee DK. Ankle arthroplasty alternatives with allograft and external fixation: preliminary clinical outcome. J Foot Ankle Surg. 2008;47:447–452. doi: 10.1053/j.jfas.2008.04.011. [PubMed] [Cross Ref]

31. Leszko F, Komistek RD, Mahfouz MR, Ratron YA, Judet T, Bonnin M, Colombier JA, Lin SS. In vivo kinematics of the Salto total ankle prosthesis. Foot Ankle Int. 2008;29:1117–1125. doi: 10.3113/FAI.2008.1117. [PubMed] [Cross Ref]

32. Morscher EW, Hefti A, Aebi U. Severe osteolysis after third-body wear due to hydroxyapatite particles from acetabular cup coating. J Bone Joint Surg Br. 1998;80:267–272. doi: 10.1302/0301-620X.80B2.8316. [PubMed] [Cross Ref]

33. Naal FD, Impellizzeri FM, Loibl M, Huber M, Rippstein PF. Habitual physical activity and sports participation after total ankle arthroplasty. Am J Sports Med. 2009;37:95–102. doi: 10.1177/0363546508323253. [PubMed] [Cross Ref]

34. Naal FD, Impellizzeri FM, Rippstein PF. Which are the most frequently used outcome instruments in studies on total ankle arthroplasty? Clin Orthop Relat Res. 2010;468:815–826. doi: 10.1007/s11999-009-1036-y. [PMC free article] [PubMed] [Cross Ref]

35. Piriou P, Culpan P, Mullins M, Cardon JN, Pozzi D, Judet T. Ankle replacement versus arthrodesis: a comparative gait analysis study. Foot Ankle Int. 2008;29:3–9. doi: 10.3113/FAI.2008.0003. [PubMed][Cross Ref]

36. Piriou P, Tremoulet J, Garreau De Loubresse C, Judet T. [Subcutaneous tenotomy of Achille’s tendon in adults for ankle stiffness: a review of 80 cases] [in French] Rev Chir Orthop Reparatrice Appar Mot. 2000;86:38–45. [PubMed]

37. Pyevich MT, Saltzman CL, Callaghan JJ, Alvine FG. Total ankle arthroplasty: a unique design. Two to twelve-year follow-up. J Bone Joint Surg Am. 1998;80:1410–1420. [PubMed]

38. Rokkum M, Reigstad A, Johansson CB. HA particles can be released from well-fixed HA-coated stems: histopathology of biopsies from 20 hips 2–8 years after implantation. Acta Orthop Scand.2002;73:298–306. doi: 10.1080/000164702320155293. [PubMed] [Cross Ref]

39. Roy-Camille R, Reignier B, Saillant G, Berteaux D. [Results of Papineua’s operation: apropos of 46 cases] [in French] Rev Chir Orthop Reparatrice Appar Mot. 1976;62:347–362. [PubMed]

40. San Giovanni TP, Keblish DJ, Thomas WH, Wilson MG. Eight-year results of a minimally constrained total ankle arthroplasty. Foot Ankle Int. 2006;27:418–426. [PubMed]

41. Schmalzried TP, Jasty M, Harris WH. Periprosthetic bone loss in total hip arthroplasty: polyethylene wear debris and the concept of the effective joint space. J Bone Joint Surg Am. 1992;74:849–863.[PubMed]

42. Skyttä ET, Koivu H, Eskelinen A, Ikävalko M, Paavolainen P, Remes V. Total ankle replacement: a population-based study of 515 cases from the Finnish Arthroplasty Register. Acta Orthop. 2010;81:114–118. doi: 10.3109/17453671003685459. [PMC free article] [PubMed] [Cross Ref]

43. Stilling M, Rahbek O, Soballe K. Inferior survival of hydroxyapatite versus titanium-coated cups at 15 years. Clin Orthop Relat Res. 2009;467:2872–2879. doi: 10.1007/s11999-009-0796-8.[PMC free article] [PubMed] [Cross Ref]

44. Sun L, Berndt CC, Gross KA, Kucuk A. Material fundamentals and clinical performance of plasma-sprayed hydroxyapatite coatings: a review. J Biomed Mater Res. 2001;58:570–592. doi: 10.1002/jbm.1056. [PubMed] [Cross Ref]

45. Sun L, Berndt CC, Khor KA, Cheang HN, Gross KA. Surface characteristics and dissolution behavior of plasma-sprayed hydroxyapatite coating. J Biomed Mater Res. 2002;62:228–236. doi: 10.1002/jbm.10315. [PubMed] [Cross Ref]

46. Tellisi N, Fragomen AT, Kleinman D, O’Malley MJ, Rozbruch SR. Joint preservation of the osteoarthritic ankle using distraction arthroplasty. Foot Ankle Int. 2009;30:318–325. doi: 10.3113/FAI.2009.0318. [PubMed] [Cross Ref]

47. Thomason K, Eyres KS. A technique of fusion for failed total replacement of the ankle: tibio-allograft-calcaneal fusion with a locked retrograde intramedullary nail. J Bone Joint Surg Br.2008;90:885–888. [PubMed]

48. Valderrabano V, Hintermann B, Dick W. Scandinavian total ankle replacement: a 3.7-year average followup of 65 patients. Clin Orthop Relat Res. 2004;424:47–56. doi: 10.1097/01.blo.0000132245.18548.09. [PubMed] [Cross Ref]

49. Valderrabano V, Pagenstert G, Horisberger M, Knupp M, Hintermann B. Sports and recreation activity of ankle arthritis patients before and after total ankle replacement. Am J Sports Med.2006;34:993–999. doi: 10.1177/0363546505284189. [PubMed] [Cross Ref]

50. Roermund PM, Marijnissen AC, Lafeber FP. Joint distraction as an alternative for the treatment of osteoarthritis. Foot Ankle Clin. 2002;7:515–527. doi: 10.1016/S1083-7515(02)00027-X. [PubMed][Cross Ref]

51. Wood PL, Deakin S. Total ankle replacement: the results in 200 ankles. J Bone Joint Surg Br.2003;85:334–341. doi: 10.1302/0301-620X.85B3.13849. [PubMed] [Cross Ref]

52. Wood PL, Prem H, Sutton C. Total ankle replacement: medium-term results in 200 Scandinavian total ankle replacements. J Bone Joint Surg Br. 2008;90:605–609. doi: 10.2106/JBJS.G.00685.[PubMed] [Cross Ref]

53. Wood PL, Sutton C, Mishra V, Suneja R. A randomised, controlled trial of two mobile-bearing total ankle replacements. J Bone Joint Surg Br. 2009;91:69–74. [PubMed]

Artroplastia total de tornozelo: experiência brasileira com a prótese HINTEGRA

Total ankle replacement: Brazilian experience with the HINTEGRA prosthesis

Caio Nery^I; Túlio Diniz Fernandes^II; Cibele Réssio^III; Mauro Luiz Fuchs^IV; Alexandre Leme de Godoy Santos^V; Rafael Trevisan Ortiz^V

^IProfessor Associado Livre-Docente do Departamento de Ortopedia e Traumatologia da Unifesp-Escola Paulista de Medicina. Chefe do Setor de Medicina e Cirurgia do Pé da Unifesp
^IIProfessor Doutor da Faculdade de Medicina da Universidade de São Paulo. Chefe do Grupo de Pé e Tornozelo do Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da FMUSP
^IIIMestre em Ortopedia pela Unifesp-Escola Paulista de Medicina. Integrante do Setor de Medicina e Cirurgia do Pé da Unifesp
^IVMédico Ortopedista do Hospital Novo Mundo - Curitiba, PR. Membro Titular da SBOT e da Associação Brasileira de Tornozelo e Pé
^VMédico Assistente do Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da FMUSP

Correspondência

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RESUMO

A artrose do tornozelo vem se tornando mais comum a cada dia. A busca por soluções que preservem a função articular fez surgir uma nova geração de próteses com três componentes e maior liberdade de movimento. Neste trabalho, apresentam-se os resultados obtidos em 10 pacientes tratados com a prótese HINTEGRA (Integra, New Deal), em ação conjunta dos Grupos do Tornozelo e Pé do DOT da Unifesp-Escola Paulista de Medicina e IOT da Faculdade de Medicina da USP-Universidade de São Paulo. Os 10 pacientes (seis mulheres e quatro homens), com idade variando de 29 a 66 anos, foram submetidos ao tratamento cirúrgico segundo a técnica de Hinterman entre janeiro e junho de 2005. Foram avaliados em intervalos predeterminados e os dados foram submetidos à análise estatística. A mobilidade do tornozelo apresentou melhora significante com a cirurgia realizada. Radiologicamente, não foram detectados sinais de soltura ou falhas nos componentes prostéticos de nenhum dos pacientes estudados. A taxa de complicações nessa amostra foi alta, mas equivalente às de outros autores e representa diretamente a curva de aprendizado relacionada com esse tipo de procedimento. Ao final de quatro anos, observaram-se significativa redução da dor e melhora do padrão funcional dos pacientes com os escores da AOFAS e de Hinterman, apontando para 20% de excelentes, 70% de bons e 10% de maus resultados. O tratamento da artrose do tornozelo através da artroplastia total com o modelo HINTEGRA, foi capaz de oferecer bons resultados no tempo médio de observação de quatro anos.

Descritores: Articulação do tornozelo; Artrodese; Osteoartrite; Artroplastia; Próteses e implantes

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ABSTRACT

Ankle arthritis is becoming more and more common. The search for solutions that preserve joint function has led to a new generation of prosthesis with three components and more degrees of freedom. This paper presents the results achieved in ten patients treated with the HINTEGRA Prosthesis (Integra, New Deal), a joint action of the Foot and Ankle Teams of DOT of Unifesp - Escola Paulista de Medicina and the School of Medicine of USP - Universidade de São Paulo. The ten patients (six women and four men), aged between 29 and 66 years, underwent a surgical procedure according to Hinterman's technique, from January to June 2005. They were evaluated at pre-arranged intervals, and the data were submitted to statistical analysis. The surgery led to a significant improvement in ankle mobility. Radiological studies showed no signs of loosening or failure in the prosthetic components in any of the patients studied. Although the rate of complications in our sample was high, it was equivalent to those of other authors, and directly represents the long, steep learning curve associate with this kind of procedure. At the end of four years, there was a significant reduction in the pain, and an improvement in functional pattern of the patients, with AOFAS and Hinterman scores indicating 20% excellent, 70% good, and 10% poor results. Despite the drawbacks, treatment of ankle arthritis through total arthroplasty with the HINTEGRA prosthesis proved to be capable of giving good results over an average observation period of four years.

Keywords: Ankle joint; Arthrosis; Osteoarthritis; Arthroplasty; Prostheses and implants

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Introdução

Embora a frequência da artrose primária do tornozelo não seja preocupante em nosso meio, suas formas pós-traumáticas e inflamatórias apresentam incidências crescentes aqui e em todo o mundo. A artrodese do tornozelo, considerada como o padrão-ouro no tratamento da artrose de qualquer etiologia, vem sendo questionada, especialmente quando nos deparamos, cada vez mais frequentemente, com acometimentos bilaterais e em indivíduos jovens. Trabalhamos sempre com o espectro da sobrecarga das articulações vizinhas e das sequelas que delas decorrem, com consequente deterioração da qualidade funcional do paciente⁽¹⁾.

Apesar das elevadas taxas de insucesso vividas com as primeiras gerações de próteses totais do tornozelo⁽²⁾, vários grupos seguiram pesquisando e hoje dispomos de diferentes implantes, cujos refinamentos se aproximam das exigências anatômicas e funcionais dessa articulação.

A análise da literatura aponta como principal avanço o conceito de "apoio móvel", em que os componentes prostéticos se relacionam com vários graus de liberdade, sem que haja constrição da articulação. As próteses de terceira geração, dotadas de três elementos - componente tibial, componente talar e componente intermediário - são as mais bem sucedidas até o presente momento^(3-5).

Nesse cenário, altamente desfavorável para os países do Terceiro Mundo em face do alto custo e da complexidade na produção, distribuição e comercialização de material cirúrgico tão sofisticado, juntaram os esforços os Grupos do Pé e Tornozelo do DOT da Unifesp-Escola Paulista de Medicina e IOT da Faculdade de Medicina da Universidade de São Paulo, no sentido de buscar aprofundar os conhecimentos, alcançar o treinamento desejável e introduzir em nosso meio a artroplastia total do tornozelo. Em função de sua qualidade, desempenho, facilidade de acesso e disponibilidade, foi escolhida a prótese HINTEGRA (Grupo Integra - EUA e New Deal - França) como sendo aquela com a qual iríamos trabalhar⁽⁵⁾.

O objetivo deste trabalho é o de apresentar os resultados obtidos com os primeiro 10 casos tratados com a prótese total de tornozelo HINTEGRA em nosso país.

Métodos

No período compreendido entre Janeiro e junho de 2005, foram realizadas 10 artroplastias totais do tornozelo pelos dois grupos já mencionados. Os pacientes foram revisados em abril de 2009, tendo sido obtidos dados clínicos e radiográficos de todos. Com essa observação, completamos o tempo médio de seguimento de quatro anos.

Nossa amostra foi composta por seis mulheres e quatro homens com idade variando de 29 a 66 anos e média de 50,2 anos. Houve equilíbrio quanto ao lado acometido. O tempo médio de envolvimento com a dor e a doença foi de 10,1 anos, variando de dois a 29 anos.

No que se refere à etiologia da artrose do tornozelo, obtivemos três casos de artrose pós-traumática, seis casos de artrose inflamatória e um caso de artrose pós-infecciosa, na qual a paciente sofrera quadro de artrite séptica 28 anos antes.

Na Tabela 1, reunimos os dados demográficos referentes aos pacientes de nossa amostra.

Todos os pacientes foram protocolados e submeteram-se ao tratamento cirúrgico seguindo estritamente a técnica cirúrgica idealizada e difundida por Beat Hintermann para a prótese HINTEGRA (New Deal, França)⁽⁶⁾.

Os registros dos pacientes foram consultados para a obtenção de dados referentes a complicações imediatas e tardias e as radiografias seriadas foram avaliadas e mensuradas à procura de sinais de desalinhamentos, desgastes e soltura dos componentes prostéticos. Além disso, foram avaliadas as condições das peças ósseas e tecidos periprostéticos.

Utilizamos o critério de "três semanas" para considerar a integridade do envelope de tecidos moles da região de tornozelo e determinar a ocorrência de complicações da ferida cirúrgica⁽⁷⁾. Segundo esse mesmo critério, complicações menores são as pequenas deiscências das feridas, necroses circunscritas às bordas da incisão e sinais de infecção superficial passíveis de tratamento através de curativos seriados. As complicações maiores compreendem todas aquelas que requeiram qualquer tipo de intervenção cirúrgica para desbridamento, drenagem ou cobertura cutânea.

Na avaliação clínica, utilizamos a escala analógico-visual da dor, o critério clínico de Hintermannpara artroplastia total de tornozelo⁽⁸⁾ (Tabela 2) e a escala AOFAS para tornozelo e retropé⁽⁹⁾.

A avaliação radiológica foi realizada em radiografias do tornozelo nas incidências anteroposterior e lateral, obtidas em ortostase, medindo-se os parâmetros sugeridos por Hintermann et al^(5,8,10).

Desalinhamento: a) Componente tibial muito curto, muito lateralizado ou medializado com desvio angular superior a 5 graus; b) Componente talar muito pequeno ou muito grande, colocado com angulação superior a 10 graus. Na colocação ideal, o componente talar deve localizar-se 5% à frente do componente tibial.

Ângulo alfa - Ângulo entre o eixo anatômico da tíbia e a superfície articular do componente tibial da prótese, na incidência AP - normal = 90 graus.

Ângulo beta - Ângulo entre o eixo anatômico da tíbia e a superfície articular do componente tibial da prótese, na incidência lateral - normal = 85 graus.

Ângulo teta - Ângulo obtido entre a linha que passa pelas extremidades anterior e posterior do componente talar da prótese e a linha que tangencia a borda superior do navicular e a eminência superior da tuberosidade posterior do calcâneo - normal = 20 graus.

Distância "a" - Distância em milímetros medida entre a extremidade anterior do componente talar da prótese e a linha que tangencia a borda superior do navicular e a eminência superior da tuberosidade posterior do calcâneo.

Distância "b" - Distância em milímetros medida entre a extremidade posterior do componente talar da prótese e a linha que tangencia a borda superior do navicular e a eminência superior da tuberosidade posterior do calcâneo.

A mobilidade real do tornozelo, definida como o arco de movimento mensurado entre os componentes tibial e talar nas radiografias laterais em flexão e extensão máximas, foi medida em nossos pacientes.

As linhas de radiolucência são definidas como linhas escuras, de largura variável, que aparecem ao redor dos componentes prostéticos. Sua ocorrência não se associa diretamente à soltura dos componentes e podem se resolver espontaneamente.

A soltura do componente tibial da prótese HINTEGRA é diagnosticada quando ocorrem mudanças superiores a dois graus nos ângulos alfa e beta ou quando surgem linhas de radiolucência com mais de 2mm de espessura.

A soltura do componente talar da HINTEGRA é diagnosticada quando ocorre afundamento no corpo do talo maior do que 5mm (distâncias "a" e "b") ou quando o ângulo teta sofre alterações superiores a cinco graus. É muito difícil avaliar as linhas de radiolucência ao redor do componente talar.

O componente intermediário, de polietileno, pode sofrer desgaste, caracterizado por seu afilamento ou fratura com perda da sustentação e bloqueio ou instabilização da prótese. As radiografias de todos os pacientes desta série foram observadas à procura desses sinais.

Os dados numéricos iniciais e finais, obtidos das mensurações angulares e lineares de todos os pacientes, foram submetidos à análise estatística pelo teste t de Student. Definimos como 5% o nível para a rejeição da hipótese de nulidade (erro alfa = 5; p = 0,05).

Resultados

Na tabela 3 apresentamos os valores de arco de movimento do tornozelo nos períodos pré e pós-operatório final (quatro anos). A mobilidade real foi positiva em 80% dos pacientes que melhoraram 17 graus em média.

São apresentadas ainda as diferenças entre os valores iniciais, mensurados nas radiografias pós-operatórias de um mês, e os valores finais, medidos nas radiografias obtidas no final do período de observação, dos ângulos alfa, beta e teta e para as medidas "a" e "b".

Houve diferença significante entre os valores médios do arco de movimento do tornozelo antes e depois da cirurgia, indicando melhora substancial com o procedimento. Exceto por um paciente (#3), os demais apresentavam valores de arco de movimento considerados como funcionais para as artroplastias totais de tornozelo (30 graus).

Embora não tenha sido apresentada na tabela, a análise comparativa da mobilidade subtalar e de valgo do retropé não mostrou diferença significante antes e depois da cirurgia (p = 0,343).

A análise estatística não detectou diferenças significantes entre os demais parâmetros estudados (ângulos alfa, beta e teta; medidas "a" e "b") que sofreram variações pequenas, situadas dentro dos limites aceitáveis definidos anteriormente, após quatro anos de seguimento.

Em dois pacientes (20%) foi necessária a realização de cirurgias associadas ao procedimento principal da artroplastia total do tornozelo. No paciente #6 foram realizados a artrodese da articulação subtalar e o alongamento do tendão calcâneo; no paciente #10, foi necessário apenas o alongamento do tendão calcâneo.

A análise das radiografias obtidas a intervalos preestabelecidos, de todos os pacientes, apontou para o surgimento de linhas de radiolucência em quatro (40%): no paciente #1 as linhas apareceram na fíbula e no talo nas radiografias de dois anos; no paciente #3, ao redor do componente tibial nas radiografias de quatro anos; no paciente #4, na área de contato do componente tibial com a fíbula nas radiografias de três meses (Figura 2); no paciente #5, ao redor do talo e tíbia nas radiografias de um ano. Essas linhas não progrediram com o tempo e não representaram sinal de soltura dos componentes prostéticos nos pacientes desta amostra.

Foram identificados três casos (30%) de desalinhamento radiográfico dos componentes prostéticos: no paciente #1 notou-se desalinhamento entre os componentes no plano coronal e transversal nas radiografias de dois anos de seguimento; no paciente #2 notou-se leve desalinhamento do componente talar no plano transversal já nas radiografias iniciais - esse posicionamento não se alterou com o tempo; no paciente #5, houve afundamento dos componentes tibial e talar sem qualquer alteração de seu alinhamento perceptível nas radiografias de quatro anos de pós-operatório (Figura 3).

Na Tabela 4 reunimos os resultados finais dos 10 pacientes incluídos neste estudo. A substituição artroplástica do tornozelo determinou redução significante do nível de dor, que passou de 7,9 em média no pré-operatório, para 2,0 ao final de quatro anos.

O escore da AOFAS também demonstrou evolução estatisticamente significante, passando de 41 pontos para 76 pontos em média com o procedimento adotado.

De acordo com o escore clínico, predominaram os resultados bons (70%) sobre os excelentes (20%) e maus (10%). Apesar do grande número de achados radiológicos potencialmente indicativos de evolução insatisfatória ou desfavorável, a constatação clínica e funcional aponta exatamente na direção oposta.

Complicações

Houve um grande número de complicações nos pacientes incluídos neste estudo. Como já foi dito, as complicações foram divididas em duas modalidades - menores e maiores - na dependência de sua gravidade e necessidade de intervenções.

Como complicações menores, tivemos dois pacientes com dermólise e deiscência da ferida cirúrgica, que responderam bem ao tratamento com curativos seriados; um paciente apresentou infecção superficial da ferida cirúrgica, tratada apenas com limpeza local; dois pacientes foram diagnosticados como portadores de fraturas maleolares transoperatórias (um do maléolo lateral e um do maléolo medial), tratados apenas com a supressão da carga por quatro semanas.

Como complicações maiores, tivemos dois pacientes com necrose das bordas da ferida cirúrgica com exposição de tendões e parte da prótese. Esses pacientes foram tratados por meio de enxertia: um deles, com enxertia livre de pele (4ª semana PO) e outro, com enxerto miocutâneo do tríceps braquial vascularizado (3ª semana) (Figura 4).

Um paciente apresentou ruptura do tendão extensor longo do hálux, que foi reparada na oitava semana pós-operatória.

Um paciente apresentou bloqueio articular devido à presença de um fragmento ósseo resultante dos cortes talares, inadvertidamente abandonado na porção posterior da cápsula da articulação tibiotársica. O problema foi corrigido através da ressecção simples do fragmento ósseo livre por meio de miniartrotomia posterolateral.

A complicação mais grave resultou de extensa vasculite, que acometeu todo o membro inferior em paciente portadora de artrite reumatoide de difícil controle (#8). Debalde, as tentativas de manutenção do membro; ao final da oitava semana pós-operatória, a medida de salvamento consistiu na amputação transtibial da perna esquerda.

Na tabela 5, reunimos as complicações encontradas em nossa amostra.

Discussão

Estimulados pelos sucessos alcançados com a artroplastia das grandes articulações de carga do membro inferior, quadril e joelho, inúmeros pesquisadores buscam a fórmula ideal para alcançar resultados semelhantes na articulação do tornozelo⁽²⁾.

Como estímulo extra, além da tendência atual de preservação da atividade e qualidade de vida, surgem as observações inequívocas acerca das complicações associadas à artrodese do tornozelo⁽¹⁾ e da superioridade funcional da artroplastia quando comparada com a fusão, ambas em longo prazo^(11-13).

Os recentes avanços na compreensão da biomecânica e fisiologia do tornozelo humano, além da experiência acumulada com as sucessivas falhas nos desenhos das próteses no passado, determinaram o surgimento das próteses não constritas, com três componentes, dotadas de estabilidade à inversão e eversão, além da liberdade para rotação axial e flexo-extensão.

A prótese HINTEGRA, criada por Beat Hintermann (Basileia, Suíça), Greta Dereymaeker (Pallenberg, Bélgica), Ramon Viladot (Barcelona, Espanha) e Patrice Diebold (Maxeville, França), conta com componentes anatomicamente desenhados, que praticamente recobrem as superfícies anatômicas, apoiando-se nas zonas mais resistentes da tíbia e do talo (osso subcondral e anel cortical), requererendo mínima ressecção óssea. Dessa forma, reproduz de forma bastante efetiva a função normal do tornozelo (Figura 5).

Sua implantação, no entanto, é repleta de detalhes técnicos e passos delicados, dos quais podem resultar erros de difícil correção ou complicações sérias.

A literatura é pródiga ao se referir às complicações da artroplastia do tornozelo, independente do modelo de prótese escolhido, e já está demonstrada a alta incidência de problemas nos primeiros casos de cada série^(5,7,14,15). Com base na análise comparativa de vários autores, estabeleceu-se a curva de aprendizado média como sendo ao redor de 50 casos^(14-20).

As fraturas maleolares e os problemas menores com o envelope de tecidos moles do tornozelo tendem a diminuir à medida que o cirurgião e sua equipe se familiarizam com os tempos da técnica e reduz-se a tensão intraoperatória. Em nossa amostra, a incidência dessas complicações se aproximou daquela de outros autores mas, infelizmente, em virtude do número de casos, ainda não experimentamos sua redução natural⁽²⁰⁾.

As complicações maiores exibem padrão similar e também tendem a se tornar menos frequentes à medida que a série de casos progride. Em nossa amostra, ambos os pacientes que apresentaram complicações mais graves (enxerto vascularizado e vasculite grave que requereu amputação transtibial) eram portadores de artrite reumatoide de evolução agressiva, o que nos alerta para o estabelecimento de regras extremas de cuidados no trato desses casos.

Dispor de equipe multidisciplinar capacitada para o suporte e solução das complicações mais frequentes é condição imperativa para todos que pretendam iniciar-se na realização de artroplastias totais do tornozelo.

As complicações - maiores ou menores - se concentraram no período pós-operatório mediato. Esse achado coincide também com o de outros autores, que apontam o primeiro ano pós-operatório como o de maior concentração de ocorrências importantes^{(14,16,19,20)}. Depois desse ano, a evolução dos pacientes é bastante tranquila e estabelece-se padrão funcional estável e duradouro que, em nossa amostra, se prolonga por quatro anos.

Curiosamente, uma vez ultrapassado o período mais turbulento, em que lidamos com as complicações mencionadas, trabalhamos na reabilitação e reintegração dos pacientes, a avaliação clínica e radiológica melhora e cristaliza-se a eficácia do método de tratamento.

Nossos números atestam essa afirmação. As queixas dolorosas de baixa intensidade, a mobilidade articular funcional e a manutenção do alinhamento e estabilidade do segmento operado garantem ao paciente qualidade de vida bastante adequada, incluindo a prática de exercícios leves e sem impacto (Figura 6). Mesmo no caso em que se observou o afundamento dos componentes prostéticos, houve manutenção do alinhamento e do padrão de mobilidade, razão pela qual o paciente considera seu resultado como bom na avaliação de quatro anos de PO.

Não observamos nenhum caso de falha do componente intermediário, soltura ou falha da prótese como um todo, não tendo havido necessidade de troca ou retirada de nenhum componente até o final de nossa observação.

Ao discutir subjetivamente com nossos pacientes sobre o procedimento realizado, registramos o entusiasmo, a satisfação e gratidão pelo tratamento recebido e com os resultados alcançados, mesmo entre os que sofreram com as complicações maiores.

Ao apresentar nossa pequena série de casos, esperamos estar colaborando no sentido de oferecer esperança e alento aos pacientes portadores de artrose grave do tornozelo, estímulo e informações aos colegas especialistas que, como nós, pretendemos progredir sempre e buscar novas soluções para antigos problemas, e subsídios técnicos para as autoridades brasileiras que ainda não liberaram o procedimento de artroplastia total do tornozelo em nosso meio.

Conclusões

Com base em nossas observações, podemos concluir que a artroplastia total do tornozelo realizada com a prótese HINTEGRA, apesar das dificuldades técnicas e da longa curva de aprendizado, é procedimento adequado, oferecendo bons resultados funcionais em prazo médio de observação de quatro anos.

Agradecimentos

Os autores agradecem a inestimável cooperação das empresas Integra (EUA), New Deal (França) e Tellus (Brasil), fabricantes e distribuidores da prótese HINTEGRA, por seu suporte à educação e treinamento das equipes e doação dos implantes utilizados neste trabalho.

REFERÊNCIAS

1. Fuchs S, Sandmann C, Skwara A, Chylarecki C. Quality of life 20 years after arthrodesis of the ankle. A study of adjacent joints. J Bone Joint Surg Br. 2003;85(7):994-8.         [ Links ]

2. Hintermann B. History of total ankle arthroplasty. In: Total ankle arthroplasty: historical overview, current conceps and future perspectives. New York: Springer-Verlag; 2005. p. 53-63.         [ Links ]

3. Hintermann B. Short and mid-term results with STAR total ankle prosthesis. Orthopade. 1999;28:792-803.         [ Links ]

4. Buchuel FF Sr, Buchuel FF Jr, Pappas MJ. Eighteen-year evaluation of cementless meniscal bearing total ankle replacent. Instruct Course Lect. 2002;51:14351.         [ Links ]

5. Hintermann B, Valderrabano V, Dereymaeker G, Dick W. The HINTEGRA ankle: rationale and short-term results of 122 consecutive ankles. Clin Orthop Rel Res. 2004;(424):57-68.         [ Links ]

6. Hintermann B. Surgical techniques. In: Total ankle arthroplasty: historical overview, current conceps and future perspectives. New York: Springer-Verlag; 2005. p. 115-31.         [ Links ]

7. Myerson MS, Mroczek K. Perioperative complications of total ankle arthroplasty. Foot Ankle Int. 2003;24(1):17-21.         [ Links ]

8. Hintermann B. Postoperative care and follow-up: radiographic measurements. In: Total ankle arthroplasty: historical overview, current conceps and future perspectives. New York: Springer-Verlag; 2005. p. 137-43.         [ Links ]

9. Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS. Clinical rating systems for the ankle-hindfoot, midfoot, hallux and lesser toes. Foot Ankle. 1994;15(7):349-53.         [ Links ]

10. Hintermann B, Valderrabano V, Knupp M, Horisberger M. The HINTEGRA ankle: short- and mid-term results. Orthopade. 2006;35(5):533-45.         [ Links ]

11. Kofoed H, Stürup J. Comparison of ankle arthroplasty and arthrodesis. A prospective series with long-term follow-up. Foot. 1994;4(1):6-9.         [ Links ]

12. Kofoed H, Sorensen TS. Ankle arthroplasty for rheumatoid arthritis and osteoarthritis: prospective long-term study of cemented replacements. J Bone Joint Surg Br. 1998;80(2):328-32.         [ Links ]

13. Kofoed H, Lundberg J. Ankle arthroplasty in patients younger and older than 50 years: a prospective series with long-term follow-up. Foot Ankle Int. 1999;20(8):501-6.         [ Links ]

14. Haskell A, Mann RA. Perioperative complications rate of total ankle replacement is reduced by surgeon experience. Foot Ankle Int. 2004;25(5):283-9.         [ Links ]

15. Saltzman CL. Perspective on total ankle replacement. Foot Ankle Clin. 2000;5(4):76175.         [ Links ]

16. Pyevich MT, Saltzman CL, Callaghan JJ, Alvine FG. Total ankle arthroplasty: a unique design. Two to twelve-year follow-up. J Bone Joint Surg Am. 1998;80(10):1410-20.         [ Links ]

17. Saltzman CL, Amendola A, Anderson R. Surgeon training and complications in total ankle arthroplasty. Foot Ankle Int. 2003;24:514-8.         [ Links ]

18. Schubert JM, Patel S, Zarutsky E. Perioperative complications of the agility total ankle replacement in 50 initial, consecutive cases. J Foot Ankle Surg. 2006;45(2):139-46.         [ Links ]

19. Wood PL, Deakin S. Total ankle replacement. The results in 200 ankles. J Bone Joint Surg Br. 2003;85(3):334-41.         [ Links ]

20. Lee KB, Cho SG, Hur CI, Yoon TR. Perioperative complications of HINTEGRA Total Ankle Replacement: our initial 50 cases. Foot Ankle Int. 2008;29(10):978-84.         [ Links ]