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External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study
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Foot and Ankle Surgery xxx (2019) xxx–xxx
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Foot and Ankle Surgery journal homepage: www.elsevier.com/locate/fas
External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study Matthias Rüschenschmidta , Martin Glombitzaa , Janosch Dahmena,b , Peter-Michael Haxa , Rolf Leferingc , Eva Steinhausena,b,* a b c
Department of Orthopedic and Trauma Surgery, BG Klinikum Duisburg, Großenbaumer Allee 250, Duisburg, 47249 Germany Faculty of Health, University of Witten/Herdecke, Alfred-Herrhausen-Straße 50, Witten, 58448 Germany Institute for Research in Operative Medicine (IFOM), University of Witten/Herdecke, Ostmerheimer Straße 200, Cologne, 51109 Germany
A R T I C L E I N F O
A B S T R A C T
Article history: Received 10 September 2018 Received in revised form 13 March 2019 Accepted 2 May 2019 Available online xxx
Background: Arthrodesis of the ankle is a salvage procedure in case of chronic ankle joint infection. External fixation still is the gold standard. We compared the outcome of external fixator versus intramedullary nailing for arthrodesis of the infected ankle joint. Methods: All patients with ankle joint infection who received arthrodesis with either external fixator or intramedullary nail between 08/2009 and 09/2017 were retrospectively analyzed. Endpoints were the successful control of infection, osseous fusion, and mobilization with full weightbearing. Results: Seventy-one patients were included. Nineteen patients (27%) suffered reinfection. Patients with intramedullary nailing showed significantly fewer reinfections (p = 0.019), achieved full weightbearing significantly more often (p = 0.042) and faster and developed significantly fewer complications (p < 0.001). Forty-three patients showed bone fusion without significant differences between the groups. Conclusions: Ankle arthrodesis with intramedullary nailing appears to be a successful alternative to the established procedure of external fixation in cases of chronic ankle joint infection. © 2019 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.
Keywords: Ankle joint infection Osteomyelitis Ankle arthrodesis Septic ankle fusion
1. Introduction Successful treatment of chronic ankle joint infection is a challenge. The aim of therapy is lasting clearance of infection as well as restoration of stability and weight carrying capacity of the extremity. Arthrodesis of the ankle is a salvage procedure, specifically aimed at preventing more proximal amputation [1–6]. A variety of reliable, mainly internal fixation methods exist for aseptic ankle arthrodesis [7–12]. In contrast to aseptic arthrodesis there are few studies in the current literature analysing the ideal treatment of septic ankle arthrodesis. In septic ankle arthrodesis external fixation is still considered to be gold standard [1,4,13–17]. The primary objective is to avoid implants in the infected bone, because it is assumed that they are a risk factor for
* Corresponding author at: Department of Orthopedic and Trauma Surgery, BG Klinikum Duisburg, Großenbaumer Allee 250, Duisburg, 47249 Germany. E-mail addresses: [email protected] (M. Rüschenschmidt), [email protected] (M. Glombitza), [email protected] (J. Dahmen), [email protected] (P.-M. Hax), [email protected] (R. Lefering), [email protected] (E. Steinhausen).
persistent or recurrent infection [1,4,14]. Early loosening and material failure are often described. Reasons cited include lower bone quality, frequently in combination with bony defects after previous debridement [5,18]. An additional advantage of external fixation is that it offers tissue protection, given an already involved situation. The arthrodesis provides the stability required for bony consolidation [3,5]. It eliminates joint motion, which may contribute to recurrent infection [1] and provides pain reduction [15,19]. Bilateral AO frame fixation and the Ilizarov technique are reliable external fixation methods [16,17,19]. However, neither external fixation methods are without complications: They include the risk of pin track infection or pin loosening [3–5,15,17], a more prolonged period of partial weightbearing, and reduced patient comfort in a noncompliant patient population [1,6,20]. Non-union is frequently reported in external arthrodesis [4,14–16]. Internal fixation, for example using retrograde intramedullary nailing, provides a high level of immediate stability and thus the possibility of early full weightbearing [6,21]. The wearing comfort is high and results in an improved patient compliance with treatment [2,22]. But the intramedullary position of osteosynthesis material is unfavourable in the case of bone infection.
https://doi.org/10.1016/j.fas.2019.05.001 1268-7731/© 2019 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: M. Rüschenschmidt, et al., External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study, Foot Ankle Surg (2019), https://doi.org/10.1016/j.fas.2019.05.001
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Some time ago we started using retrograde intramedullary nailing for arthrodesis in septic ankles. In all cases, active infection was eradicated prior to arthrodesis. This retrospective study compares the outcome of external fixation versus retrograde intramedullary nailing in septic ankle arthrodesis. 2. Material and methods 2.1. Patients collective A retrospective analysis was conducted of all patients treated in our institution for chronic infection of the ankle (septic arthritis with facultative osteomyelitis of the distal tibia or the talus) who underwent ankle arthrodesis between August 2009 and September 2017. Three different methods of arthrodesis were compared: Internal fixation using a retrograde intramedullary nail, external fixation using external AO frame and the Ilizarov technique. External fixation was used over the entire period; retrograde intramedullary nailing was used beginning in 2014. The decision to treatment method was determined individually by surgeonspreference since 2014. Patients younger than 18 years and those treated with a different method of arthrodesis (e.g. screw fixation) were excluded. The primary endpoint was the successful control of infection. Secondary endpoints were osseous union and functional outcome focusing on mobilisation with full weightbearing. All complications, such as recurrent infection, revision surgery and failure of therapy were recorded. Epidemiologic data, the pre-, peri- and postoperative course were gathered from the digital patient files and processed anonymously. Bony fusion was quantified by evaluating an X-ray or CT scan. The radiology report was compared with the authors’ findings. Fusion was defined as the presence of complete cortical bridging in three out of four cortices (anterior, posterior, medial and lateral), respectively no evidence of the fracture line. Followup was analysed at the latest February 2018. 2.2. Surgery In all cases active infection was eradicated prior to arthrodesis. This included the removal of osteosynthesis material, debridement, local and/or systemic antibiotics and, if necessary, tissue transfer. If intraoperative microbiology samples were sterile, intravenous antibiotic therapy according to the previous resistance was
performed for 10–14 days. If a causative microbe was identified, intravenous antibiotic therapy was conducted for 21 days. In the presence of a difficult-to-treat pathogen, oral antibiotic therapy was given for three more weeks. This staged protocol was used in all groups. Persistently positive bacterial cultures led to mandated further debridement. Once they began to receive care at our institute, all patients were treated exclusively by the specialised team of the septic surgery department. Ankle arthrodesis was conducted with bony contact between the tibial and talar resection surface. Due to the joint resection leg shortening resulted up to 2 cm. 2.3. Statistics Therapy methods were compared using Pearson’s chi-squared test. Statistical analysis was performed using SPSS (Version 24, IBM Inc., Armonk, NY, USA). A p-value less than 0.05 (p < 0.05) was considered statistically significant. Seventy patients would be sufficient to detect a reduction in the reinfection rate from 30% to 10% with 80% power. The study was approved by the institution’s associated ethics board. Each patient consented to take part in the study. 3. Results 3.1. Epidemiology/preoperative results Seventy-one patients were included in this study. Thirty-eight patients were primarily treated with an external AO frame, 15 with an Ilizarov ring fixator and 18 using retrograde intramedullary nailing. Since we use retrograde intramedullary nailing for septic ankle arthrodesis, the number of patients treated with external fixator decreased continuously (external fixator until 2014: n = 36, 68%; external fixator after 2014: n = 17, 32%). In particular, the number of patients treated with external AO frame decreased. As a whole, the external fixator group and the nail group were comparable with respect to epidemiologic and preoperative data (Table 1). 3.2. Intraoperative results Thirty-four patients (48%) received autologous bone graft and/ or bone graft substitutes in addition to the arthrodesis to refill – non-segmental – bone defects (Table 1).
Table 1 Comparison of pre-, peri- and postoperative data between AO frame, Ilizarov ring fixator and retrograde intramedullary nail. External fixator
Number of patients Epidemiology/preoperative data Age (mean in y) Sex (male, %) Open fracture (n, %) I /II /III open fracture (n) No. of previous operations (<5/5–10/ > 10) Flaps prior to arthrodesis (n, %) Multidrug resistant pathogens (n, %) Multiple pathogens (n,%) Failed arthrodesis (n, %) Peri-/postoperative data Intraop microbiology positive (n, %) Additional defect filling (n, %)
Retrograde intramedullary nailing
p-Value
AO external fixator
Ilizarov fixator
Total external fixator
38
15
53
18
57 24 (63%) 11 (29%) 1/8/2 14/16/8 (37%/42%/21%) 12 (32%) 6 (16%) 8 (21%) 4 (11%)
54 10 (67%) 4 (27%) 1/1/2 6/5/4 (40%/33%/27%) 3 (20%) 5 (33%) 4 (27%) 6 (40%)
56 34 (64%) 15 (28%) 2/9/4 20/21/12 (38%/39%/23%) 15 (28%) 11 (21%) 12 (23%) 10 (19%)
59 13 (72%) 6 (33%) 0/5/1 3/11/4 (17%/61%/22%) 3 (17%) 4 (22%) 4 (22%) 5 (28%)
n.s. n.s. n.s.
19/31 (61%) 15 (39%)
7/12 (58%) 11 (73%)
26/43 (60%) 26 (49%)
5 (28%) 8 (44%)
p = 0.02 n.s.
n.s. n.s. n.s. n.s.
n.s. not significant.
Please cite this article in press as: M. Rüschenschmidt, et al., External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study, Foot Ankle Surg (2019), https://doi.org/10.1016/j.fas.2019.05.001
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The samples taken intraoperatively showed persistent bacteria in 31 patients (44%), although no pathogens were detected in the last debridement prior to arthrodesis. Patients with external fixation were proven to have persistent pathogens significantly more often (Table 1). External fixators were applied for 20.2 9.5 weeks on average (Median 19 weeks). The period was significant shorter in patients with the AO external fixator than in patients with the Ilizarov fixator (AO 17.6 6.3 weeks versus Ilizarov 26.5 12.8 weeks, p = 0.011). We performed leg lengthening using the Ilizarov fixator in five of 15 patients (min 2 cm, max 8 cm) due to segmental bone defects.
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union (p = 0.003). In contrast, the number of previous operations did not have any effect. Furthermore, patients with a previous local or free tissue transfer did not develop more complications than patients without any tissue transfer. In 21 patients with external fixation where arthrodesis failed, a second arthrodesis was performed during follow-up with a change to intramedullary nailing in 18 cases. Of these cases nine patients achieved osseous fusion (50%) after an average of 29 weeks (22.7; Median 20 weeks). No second arthrodesis was conducted in patients primarily treated with an intramedullary nail. Four patients (5.6%) underwent amputation during follow-up due to recurrent infection. Three of these patients had been treated with an AO frame, and one with an Ilizarov ring fixator.
3.3. Primary and secondary endpoints/follow-up 4. Discussion Average follow-up lasted 18 months (15.92, Median 15 months). Infection was permanently resolved after arthrodesis in 52 cases, whereas re-exacerbation occurred in 19 patients (27%). The nail group had a significantly lower re-exacerbation rate when compared to the external fixator group (nail 5.6% vs. external fixator 34%; p = 0.019) (Fig. 1). Full weightbearing was achieved significantly more often in the nail group (nail n = 16/18, external fixator n = 33/53; p = 0.042). Moreover, full weightbearing was accomplished earlier in the nail group when compared to the external fixator group (22 vs. 51 weeks). Across all three groups, radiological bone fusion was seen in 43 patients (61%) by the end of follow-up (Fig. 2–4). The difference between internal and external fixation was not statistically significant (p = 0.101), although more frequent in the nail group (nail: 78%, external fixator: 55%) (Fig. 5). Furthermore, consolidation was achieved faster in patients with intramedullary nailing (nail: 35 weeks, AO frame: 58 weeks, Ilizarov: 60 weeks). Evidence of multidrug resistant pathogens or a culture with more than two species before arthrodesis were risk factors for failure of osseous fusion in all groups. In the presence of a sole multidrug resistant pathogen, only three out of eleven reached consolidation (27%). In the presence of a bacterial spectrum with at least three different pathogens, nine out of 16 reached osseous fusion (56%). The nail group had significantly fewer complications (p < 0.001) and non-unions (p < 0.001) than the external fixator group (Figs. 1,5). A positive bacterial culture at the time of arthrodesis surgery was associated with postoperative complications as well as non-
Fig. 1. Comparison of rate of complications between AO frame, Ilizarov ring fixator and retrograde intramedullary nail.
External fixation still is considered as the gold standard in septic ankle arthrodesis [1,4,13–17]. Internal and intramedullary procedures are rarely used to avoid implants in the infected bone. Nevertheless, we briefly use retrograde intramedullary nails for septic ankle arthrodesis. The objective of our study is to compare the outcome of external fixation versus retrograde intramedullary nailing for septic ankle arthrodesis. With respect to primary and secondary endpoints, the nail group was superior. Patients in the nail group had significant fewer recurrent infections, achieved full weightbearing significantly more often and faster, and had significantly fewer complications. Moreover, patients in the nail group achieved osseous fusion more often, but this difference was not statistically significant. To our knowledge, our analysis represents the largest patient cohort to date comparing internal and external methods for septic ankle arthrodesis. While there are numerous comparative studies concerning aseptic ankle arthrodesis and studies concerning retrograde intramedullary nailing [7–9,21,23], there are only a few studies about septic ankle arthrodesis (Table 2). Comparative studies are particularly rare [1,3]. A further complicating factor is that the comparability of the existing studies is limited by inconsistent study design, heterogeneous patient collectives, and varying end points [5]. Moore et al. [1] compared internal and external surgical procedures in septic ankle arthrodesis. Both methods achieved similar results concerning limb salvage, final functional status, infection clearance and bony union. However, they analysed a smaller number of cases (n = 32) than we did. Furthermore, the “internal group” included several operative techniques, such as arthrodesis with screws or nail. This variation complicates the comparability. Hulscher et al. [3] also compared external and internal surgical procedures in septic ankle arthrodesis. They included only 19 patients and the internal group was quite diverse once again (screws, plate, k-wire fixation). There were no significant differences between the operative procedures in terms of the fusion rate. Kappler et al. [6] analysed retrograde intramedullary nailing in 49 septic ankle arthrodesis without a control group. 85.7% achieved bony fusion. 10.2% suffered reinfection. In our study, 77.8% of the nail group achieved osseous fusion during follow-up, but only 5.6% suffered reinfection. Richter et al. [5] analysed the results of combined internal and external arthrodesis in 45 patients with septic ankles. The authors mention the high complication rate for external fixation. Other authors also describe a high complication rate for external fixation [3,4,15,17]. There is an increased risk of pin tract infection, even if the patient is compliant with aftercare [7,9,14]. In addition, an external fixator is not convenient for the patient and
Please cite this article in press as: M. Rüschenschmidt, et al., External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study, Foot Ankle Surg (2019), https://doi.org/10.1016/j.fas.2019.05.001
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Fig. 2. Ankle arthrodesis with AO frame. (1) Primary osteosynthesis. (2) Distance arthrodesis with AO frame and enclosed gentamycin chains. (3) After removal of the gentamycin chains and final arthrodesis. (4) After removal of the external fixator and bone fusion of the arthrodesis.
Fig. 3. Segmental transport and ankle arthrodesis with Ilizarov fixator. (1) Arthrodesis, distance arthrodesis with Ilizarov fixator and enclosed gentamycin chains. (2) Segmental transport. (3) Increasing formation of new bone proximal and increasing fusion of the ankle arthrodesis. (4) After removal of the Ilizarov fixator with new bone proximal. (5) Consolidation of the ankle arthrodesis.
Fig. 4. Ankle arthrodesis with retrograde intramedullary nail. (1) Primary osteosynthesis. (2) Chronic ankle joint infection with lysis. (3) Ankle arthrodesis with retrograde intramedullary nail. (4) Increasing bone fusion of the arthrodesis. (5) After removing the intramedullary nail: consolidation of the ankle arthrodesis.
makes mobilisation more difficult [3,9]. Full weightbearing is not allowed with the AO frame to prevent loosening of the pins [16]. This consideration does not apply to the Ilizarov ring fixator. Biomechanical studies demonstrated comparable stability
with either a retrograde intramedullary nail, screw arthrodesis or an Ilizarov ring fixator [24,25]. Stability is an important factor for both osseous fusion and permanent infection clearance [1,3,5].
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Fig. 5. Flowchart depicting the rate of bone fusion respective rate of non-union relating to AO frame, Ilizarov fixator and retrograde intramedullary nail.
Table 2 studies concerning septic ankle fusions. No. of septic fusions
Method of fixation
Fusion rate (%)
Reinfection rate (%)
Complication rate (%) (major/ minor)
1999 45 2001 19
45 19
86.6 84.2
20 n.a.
/62 42.1
Kollig Schmidt Saltzman Salem Rochmanb Dalla Paolaa Kovoor Kienast El-Alfy Chen
2003 2005 2005 2006 2008 2009
15 107 8 22 11 45
15 107 8 17 11 45
Internal + External fixation External (8) vs. internal (8) vs. combination (3) Hybrid external fixator External fixation (AO vs. Ilizarov) Ilizarov external fixator Ilizarov external fixator Ilizarov external fixator External fixator
93 86.9 87.5 95 90.9 86.7
20 14 0 17.6 0 8.9
n.a. 27 50 50 54.5 n.a.
2009 2010 2010 2010
20 133 12 12
17 133 7 12
95 91.7 91.7 100
15 4.5 0 0
45 20.3 16.7/75 33
Klouche Gessmann Pawara Kappler Gross Moore Kawoosa Suda
2011 2011 2013 2014 2014 2015 2015 2016
20 37 5 49 30 30 16 79
20 37 5 49 6 32 3 79
Ilizarov external fixator AO external fixator Ilizarov external fixator Combined Ilizarov + intramedullary nailing Screws Ilizarov external fixator Coated nail Retrograde nailing Intramedullary nail Internal vs. external fixation Ilizarov external fixator External fixation
89.5 94.6 100 85.7 86 72 100 85
15 5.4 0 10.2 n.a. 18.8 n.a. 22.8
25 18.9/27 n.a. 14.3 24/56 40.6 0/43.8 60.8
Author
Year
Richter Hulscher
No. of patients
n.a. not available. a Charcot foot and ankle osteomyelitis. b Infection of the Talus, tibio-calcaneal arthrodesis.
Another advantage of the Ilizarov ring fixator is the possibility of segmental transport for leg lengthening [26]. We successfully performed leg lengthening using the Ilizarov fixator in five of 15 patients (min 2 cm, max 8 cm). But viewed as a whole, an external fixator demands a high level of compliance for months — in a non-compliant patient population [1,9]. Moore et al. [1] argue that the negative aspects of external fixators outweigh any potential benefits when compared to internal fixation. The overall reinfection rate after septic ankle arthrodesis is reported as 0–22% in the current literature (Table 2). The results are hard to compare due to differences in study design. In our study, we saw a significant difference in the reinfection rate between the nail group and the external fixator group. The rate of osseous fusion after septic ankle arthrodesis is reported as 69–100% in the current literature (Table 2). The period of time until
radiologically verified bony fusion varies between 4.8 and 8.5 months [1,2,4,13,16]. We found comparable fusion rates in our nail group, but the fusion rate in our external fixator group was worse. The period of time until bony fusion (including primary therapy failures) was comparable to the results of other published studies. The time period until full weightbearing varies between 4 and 7.3 months in the current literature, and in extreme cases, time periods as long as 19 months are reported [3,5,13,16]. All in all, our results are comparable to those in other studies, but our nail group was superior to our external fixator group. Generally satisfactory results for internal procedures in septic ankle arthrodesis are described in the current literature despite implants in the infected bone, but the number of studies and the number of cases are small. Hulscher et al. [3] suggest the need for a consistent, step-bystep approach with eradication of the infection, adequate soft
Please cite this article in press as: M. Rüschenschmidt, et al., External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study, Foot Ankle Surg (2019), https://doi.org/10.1016/j.fas.2019.05.001
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tissue coverage and consolidation of the arthrodesis in case of septic ankle arthrodesis. As a rule, we perform successive surgical debridement procedures until we no longer detect any pathogens. Despite such caution, we still found pathogens in the intraoperative biopsies in 31 patients. The extent to which bacterial species and bacterial resistance influence the result remains to be definitively resolved. Whereas Kovoor et al. [27] identify no relevant influence, preoperative positive bacterial cultures with multidrug resistant pathogens or greater than two different species proved to be a risk factor for non-union in our patient population. A major objective of septic ankle arthrodesis is to avoid amputation of the affected leg. In case of persistent infection or unsuccessful arthrodesis, amputation may be unavoidable. The rate of amputation in the current literature varies between 2% and 10.5% [1–3,5,6,15,16]. Four out of 71 of our patients (5.6%) required amputation. All of these patients had received a septic ankle arthrodesis via external fixator. There are some limitations to our study. We cannot exclude selection bias due to the non-randomised study design. In the past, we solely used external fixators for septic ankle arthrodesis. Since we use retrograde intramedullary nailing for septic ankle arthrodesis, the number of patients treated with external fixator decreased continuously. The decision to treatment method was determined individually by surgeons’ preference since 2014. By now we predominantly use intramedullary nails – even in the case of multidrug resistant pathogens or in presence of multiple pathogens – because of good long-term results for nearly five years. Only if retrograde nailing is not possible for technical reasons, we use an external fixator. An Ilizarov ring fixator is still applied, if a segmental bone transport is conducted. However, the internal and the external fixation group were comparable regarding epidemiologic and preoperative data (Table 1). In particular no relevant clinical differences were found concerning number of preoperative multidrug resistance or multiple pathogens (multidrug resistant pathogen: nail 22% vs. external fixator 21%; multiple pathogens: nail 22% vs. external fixator 23%). In both groups arthrodesis was performed only if the last debridement showed sterile microbiological cultures. But the groups are of unequal number of patients with fewer patients in the nail-group. Furthermore, patients in the nail-group have a shorter follow-up period, because we began using this operative procedure for septic ankle arthrodesis only a few years ago. The degree to which the significantly lower reinfection rate in the nail group is the consequence of the shorter follow-up period needs to be evaluated in further follow-up. The overall lower fusion rate in our study compared to other studies may be influenced by the shorter follow-up period, too. Our early results of septic ankle arthrodesis using intramedullary nails are promising, and even better than septic ankle arthrodesis using external fixators with respect to our primary and secondary endpoints. In our opinion, the high stability, which can be achieved with an intramedullary nail is of essential importance for successful treatment, even in the case of a history of sepsis. Further long-term follow-up is necessary. 5. Conclusions In summary, retrograde nailing appears to be a promising alternative to established external arthrodesis procedures in septic ankle arthrodesis – despite the intramedullary location. Radical surgical debridement is required. The high stability is essential. The early weightbearing is advantageous. The disadvantages of external fixation – poor comfort, pin infections, partial weightbearing – do not apply.
Funding This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors. Ethics approval This study was favorably evaluated by the Ethics Committee of Witten/Herdecke University (No. 67/2017). Conflict of interest statement The authors declare, that they have no conflicts of interests or financial conflicts. Consent for publication We obtained informed consent from the analyzed patients. Level of evidence IIIb, retrospective comparative series Registration of clinical trials Registration trial DRKS00014008. Data statement The datasets analysed during the current studyare available from the corresponding author on reasonable request. CRediT authorship contribution statement Matthias Rüschenschmidt: Writing - original draft. Martin Glombitza: Conceptualization. Janosch Dahmen: Investigation, Writing - review & editing. Peter-Michael Hax: Writing - review & editing. Rolf Lefering: Formal analysis, Methodology, Writing review & editing. Eva Steinhausen: Writing - original draft, Conceptualization, Project administration. References [1] Moore J, Berberian WS, Lee M. An analysis of 2 fusion methods for the treatment of osteomyelitis following fractures about the ankle. Foot Ankle Int 2015;36(5):547–55. [2] Klouche S, El-Masri F, Graff W, Mamoudy P. Arthrodesis with internal fixation of the infected ankle. J Foot Ankle Surg 2011;50(1):25–30. [3] Hulscher JB, te Velde EA, Schuurman AH, Hoogendoorn JM, Kon M, van der Werken C. Arthrodesis after osteosynthesis and infection of the ankle joint. Injury 2001;32(2):145–52. [4] Suda AJ, Richter A, Abou-Nouar G, Jazzazi M, Tinelli M, Bischel OE. Arthrodesis for septic arthritis of the ankle: risk factors and complications. Arch Orthop Trauma Surg 2016;136(10):1343–8. [5] Richter D, Hahn MP, Laun RA, Ekkernkamp A, Muhr G, Ostermann PA. Arthrodesis of the infected ankle and subtalar joint: technique, indications, and results of 45 consecutive cases. J Trauma 1999;47(6):1072–8. [6] Kappler C, Staubach R, Abdulazim A, Kemmerer M, Walter G, Hoffmann R. Hindfoot arthrodesis for post-infectious ankle destruction using an intramedullary retrograde hindfoot nail. Unfallchirurg 2014;117(4):348–54. [7] Buchner M, Sabo D. External or internal fixation for arthrodesis of the ankle – a comparative study of perioperative and long-term results. Unfallchirurg 2003;106(6):472–7. [8] Muckley T, Schutz T, Srivastava S, Goebel M, Gonschorek O, Buhren V. Ankle arthrodesis with intramedullary compression nailing. Unfallchirurg 2003;106 (9):732–40. [9] Easley ME, Montijo HE, Wilson JB, Fitch RD, Nunley JA. 2nd. Revision tibiotalar arthrodesis. J Bone Joint Surg Am 2008;90(6):1212–23. [10] Zwipp H, Rammelt S, Endres T, Heineck J. High union rates and function scores at midterm followup with ankle arthrodesis using a four screw technique. Clin Orthop Relat Res 2010;468(4):958–68. [11] Jerosch J. Arthroscopic in situ arthrodesis of the upper ankle. Orthopade 2005;34(12):1198–208.
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M. Rüschenschmidt et al. / Foot and Ankle Surgery xxx (2019) xxx–xxx [12] Rowan R, Davey KJ. Ankle arthrodesis using an anterior AO T plate. J Bone Joint Surg Br 1999;81(1):113–6. [13] Kollig E, Esenwein SA, Muhr G, Kutscha-Lissberg F. Fusion of the septic ankle: experience with 15 cases using hybrid external fixation. J Trauma 2003;55 (4):685–91. [14] Gessmann J, Ozokyay L, Fehmer T, Muhr G, Seybold D. Arthrodesis of the infected ankle joint: results with the Ilizarov external fixator. Z Orthop Unfall 2011;149(2):212–8. [15] Kienast B, Kiene J, Gille J, Thietje R, Gerlach U, Schulz AP. Posttraumatic severe infection of the ankle joint - long term results of the treatment with resection arthrodesis in 133 cases. Eur J Med Res 2010;15(2):54–8. [16] Schmidt HG, Hadler D, Gerlach UJ, Schoop R. Principles of OSG arthrodesis in cases of joint infection. Orthopade 2005;34(12):1216–28. [17] El-Alfy B. Arthrodesis of the ankle joint by Ilizarov external fixator in patients with infection or poor bone stock. Foot Ankle Surg 2010;16(2):96–100. [18] Raikin SM, Rampuri V. An approach to the failed ankle arthrodesis. Foot Ankle Clin 2008;13(3)401–16 viii.. [19] Nihal A, Gellman RE, Embil JM, Trepman E. Ankle arthrodesis. Foot Ankle Surg 2008;14(1):1–10. [20] Dalla Paola L, Brocco E, Ceccacci T, Ninkovic S, Sorgentone S, Marinescu MG, et al. Limb salvage in Charcot foot and ankle osteomyelitis: combined use single stage/double stage of arthrodesis and external fixation. Foot Ankle Int 2009;30(11):1065–70.
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[21] Gross JB, Belleville R, Nespola A, Poircuitte JM, Coudane H, Mainard D, et al. Influencing factors of functional result and bone union in tibiotalocalcaneal arthrodesis with intramedullary locking nail: a retrospective series of 30 cases. Eur J Orthop Surg Traumatol 2014;24(4):627–33. [22] Klos K, Drechsel T, Gras F, Pfeil A, Tiemann A, Hofmann GO, et al. [Tibiotalocalcaneal arthrodesis using a compressive retrograde locking nail with hindfoot valgus]. Z Orthop Unfall 2009;147(4):445–51. [23] Millett PJ, O’Malley MJ, Tolo ET, Gallina J, Fealy S, Helfet DL. Tibiotalocalcaneal fusion with a retrograde intramedullary nail: clinical and functional outcomes. Am J Orthop (Belle Mead NJ) 2002;31(9):531–6. [24] Fragomen AT, Meyers KN, Davis N, Shu H, Wright T, Rozbruch SR. A biomechanical comparison of micromotion after ankle fusion using 2 fixation techniques: intramedullary arthrodesis nail or Ilizarov external fixator. Foot Ankle Int 2008;29(3):334–41. [25] Ogut T, Glisson RR, Chuckpaiwong B, Le IL, Easley ME. External ring fixation versus screw fixation for ankle arthrodesis: a biomechanical comparison. Foot Ankle Int 2009;30(4):353–60. [26] Sakurakichi K, Tsuchiya H, Uehara K, Kabata T, Yamashiro T, Tomita K. Ankle arthrodesis combined with tibial lengthening using the Ilizarov apparatus. J Orthop Sci 2003;8(1):20–5. [27] Kovoor CC, Padmanabhan V, Bhaskar D, George VV, Viswanath S. Ankle fusion for bone loss around the ankle joint using the Ilizarov technique. J Bone Joint Surg Br 2009;91(3):361–6.
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Foot and Ankle Surgery xxx (2019) xxx–xxx
Contents lists available at ScienceDirect
Foot and Ankle Surgery journal homepage: www.elsevier.com/locate/fas
External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study Matthias Rüschenschmidta , Martin Glombitzaa , Janosch Dahmena,b , Peter-Michael Haxa , Rolf Leferingc , Eva Steinhausena,b,* a b c
Department of Orthopedic and Trauma Surgery, BG Klinikum Duisburg, Großenbaumer Allee 250, Duisburg, 47249 Germany Faculty of Health, University of Witten/Herdecke, Alfred-Herrhausen-Straße 50, Witten, 58448 Germany Institute for Research in Operative Medicine (IFOM), University of Witten/Herdecke, Ostmerheimer Straße 200, Cologne, 51109 Germany
A R T I C L E I N F O
A B S T R A C T
Article history: Received 10 September 2018 Received in revised form 13 March 2019 Accepted 2 May 2019 Available online xxx
Background: Arthrodesis of the ankle is a salvage procedure in case of chronic ankle joint infection. External fixation still is the gold standard. We compared the outcome of external fixator versus intramedullary nailing for arthrodesis of the infected ankle joint. Methods: All patients with ankle joint infection who received arthrodesis with either external fixator or intramedullary nail between 08/2009 and 09/2017 were retrospectively analyzed. Endpoints were the successful control of infection, osseous fusion, and mobilization with full weightbearing. Results: Seventy-one patients were included. Nineteen patients (27%) suffered reinfection. Patients with intramedullary nailing showed significantly fewer reinfections (p = 0.019), achieved full weightbearing significantly more often (p = 0.042) and faster and developed significantly fewer complications (p < 0.001). Forty-three patients showed bone fusion without significant differences between the groups. Conclusions: Ankle arthrodesis with intramedullary nailing appears to be a successful alternative to the established procedure of external fixation in cases of chronic ankle joint infection. © 2019 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.
Keywords: Ankle joint infection Osteomyelitis Ankle arthrodesis Septic ankle fusion
1. Introduction Successful treatment of chronic ankle joint infection is a challenge. The aim of therapy is lasting clearance of infection as well as restoration of stability and weight carrying capacity of the extremity. Arthrodesis of the ankle is a salvage procedure, specifically aimed at preventing more proximal amputation [1–6]. A variety of reliable, mainly internal fixation methods exist for aseptic ankle arthrodesis [7–12]. In contrast to aseptic arthrodesis there are few studies in the current literature analysing the ideal treatment of septic ankle arthrodesis. In septic ankle arthrodesis external fixation is still considered to be gold standard [1,4,13–17]. The primary objective is to avoid implants in the infected bone, because it is assumed that they are a risk factor for
* Corresponding author at: Department of Orthopedic and Trauma Surgery, BG Klinikum Duisburg, Großenbaumer Allee 250, Duisburg, 47249 Germany. E-mail addresses: [email protected] (M. Rüschenschmidt), [email protected] (M. Glombitza), [email protected] (J. Dahmen), [email protected] (P.-M. Hax), [email protected] (R. Lefering), [email protected] (E. Steinhausen).
persistent or recurrent infection [1,4,14]. Early loosening and material failure are often described. Reasons cited include lower bone quality, frequently in combination with bony defects after previous debridement [5,18]. An additional advantage of external fixation is that it offers tissue protection, given an already involved situation. The arthrodesis provides the stability required for bony consolidation [3,5]. It eliminates joint motion, which may contribute to recurrent infection [1] and provides pain reduction [15,19]. Bilateral AO frame fixation and the Ilizarov technique are reliable external fixation methods [16,17,19]. However, neither external fixation methods are without complications: They include the risk of pin track infection or pin loosening [3–5,15,17], a more prolonged period of partial weightbearing, and reduced patient comfort in a noncompliant patient population [1,6,20]. Non-union is frequently reported in external arthrodesis [4,14–16]. Internal fixation, for example using retrograde intramedullary nailing, provides a high level of immediate stability and thus the possibility of early full weightbearing [6,21]. The wearing comfort is high and results in an improved patient compliance with treatment [2,22]. But the intramedullary position of osteosynthesis material is unfavourable in the case of bone infection.
https://doi.org/10.1016/j.fas.2019.05.001 1268-7731/© 2019 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: M. Rüschenschmidt, et al., External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study, Foot Ankle Surg (2019), https://doi.org/10.1016/j.fas.2019.05.001
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Some time ago we started using retrograde intramedullary nailing for arthrodesis in septic ankles. In all cases, active infection was eradicated prior to arthrodesis. This retrospective study compares the outcome of external fixation versus retrograde intramedullary nailing in septic ankle arthrodesis. 2. Material and methods 2.1. Patients collective A retrospective analysis was conducted of all patients treated in our institution for chronic infection of the ankle (septic arthritis with facultative osteomyelitis of the distal tibia or the talus) who underwent ankle arthrodesis between August 2009 and September 2017. Three different methods of arthrodesis were compared: Internal fixation using a retrograde intramedullary nail, external fixation using external AO frame and the Ilizarov technique. External fixation was used over the entire period; retrograde intramedullary nailing was used beginning in 2014. The decision to treatment method was determined individually by surgeonspreference since 2014. Patients younger than 18 years and those treated with a different method of arthrodesis (e.g. screw fixation) were excluded. The primary endpoint was the successful control of infection. Secondary endpoints were osseous union and functional outcome focusing on mobilisation with full weightbearing. All complications, such as recurrent infection, revision surgery and failure of therapy were recorded. Epidemiologic data, the pre-, peri- and postoperative course were gathered from the digital patient files and processed anonymously. Bony fusion was quantified by evaluating an X-ray or CT scan. The radiology report was compared with the authors’ findings. Fusion was defined as the presence of complete cortical bridging in three out of four cortices (anterior, posterior, medial and lateral), respectively no evidence of the fracture line. Followup was analysed at the latest February 2018. 2.2. Surgery In all cases active infection was eradicated prior to arthrodesis. This included the removal of osteosynthesis material, debridement, local and/or systemic antibiotics and, if necessary, tissue transfer. If intraoperative microbiology samples were sterile, intravenous antibiotic therapy according to the previous resistance was
performed for 10–14 days. If a causative microbe was identified, intravenous antibiotic therapy was conducted for 21 days. In the presence of a difficult-to-treat pathogen, oral antibiotic therapy was given for three more weeks. This staged protocol was used in all groups. Persistently positive bacterial cultures led to mandated further debridement. Once they began to receive care at our institute, all patients were treated exclusively by the specialised team of the septic surgery department. Ankle arthrodesis was conducted with bony contact between the tibial and talar resection surface. Due to the joint resection leg shortening resulted up to 2 cm. 2.3. Statistics Therapy methods were compared using Pearson’s chi-squared test. Statistical analysis was performed using SPSS (Version 24, IBM Inc., Armonk, NY, USA). A p-value less than 0.05 (p < 0.05) was considered statistically significant. Seventy patients would be sufficient to detect a reduction in the reinfection rate from 30% to 10% with 80% power. The study was approved by the institution’s associated ethics board. Each patient consented to take part in the study. 3. Results 3.1. Epidemiology/preoperative results Seventy-one patients were included in this study. Thirty-eight patients were primarily treated with an external AO frame, 15 with an Ilizarov ring fixator and 18 using retrograde intramedullary nailing. Since we use retrograde intramedullary nailing for septic ankle arthrodesis, the number of patients treated with external fixator decreased continuously (external fixator until 2014: n = 36, 68%; external fixator after 2014: n = 17, 32%). In particular, the number of patients treated with external AO frame decreased. As a whole, the external fixator group and the nail group were comparable with respect to epidemiologic and preoperative data (Table 1). 3.2. Intraoperative results Thirty-four patients (48%) received autologous bone graft and/ or bone graft substitutes in addition to the arthrodesis to refill – non-segmental – bone defects (Table 1).
Table 1 Comparison of pre-, peri- and postoperative data between AO frame, Ilizarov ring fixator and retrograde intramedullary nail. External fixator
Number of patients Epidemiology/preoperative data Age (mean in y) Sex (male, %) Open fracture (n, %) I /II /III open fracture (n) No. of previous operations (<5/5–10/ > 10) Flaps prior to arthrodesis (n, %) Multidrug resistant pathogens (n, %) Multiple pathogens (n,%) Failed arthrodesis (n, %) Peri-/postoperative data Intraop microbiology positive (n, %) Additional defect filling (n, %)
Retrograde intramedullary nailing
p-Value
AO external fixator
Ilizarov fixator
Total external fixator
38
15
53
18
57 24 (63%) 11 (29%) 1/8/2 14/16/8 (37%/42%/21%) 12 (32%) 6 (16%) 8 (21%) 4 (11%)
54 10 (67%) 4 (27%) 1/1/2 6/5/4 (40%/33%/27%) 3 (20%) 5 (33%) 4 (27%) 6 (40%)
56 34 (64%) 15 (28%) 2/9/4 20/21/12 (38%/39%/23%) 15 (28%) 11 (21%) 12 (23%) 10 (19%)
59 13 (72%) 6 (33%) 0/5/1 3/11/4 (17%/61%/22%) 3 (17%) 4 (22%) 4 (22%) 5 (28%)
n.s. n.s. n.s.
19/31 (61%) 15 (39%)
7/12 (58%) 11 (73%)
26/43 (60%) 26 (49%)
5 (28%) 8 (44%)
p = 0.02 n.s.
n.s. n.s. n.s. n.s.
n.s. not significant.
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The samples taken intraoperatively showed persistent bacteria in 31 patients (44%), although no pathogens were detected in the last debridement prior to arthrodesis. Patients with external fixation were proven to have persistent pathogens significantly more often (Table 1). External fixators were applied for 20.2 9.5 weeks on average (Median 19 weeks). The period was significant shorter in patients with the AO external fixator than in patients with the Ilizarov fixator (AO 17.6 6.3 weeks versus Ilizarov 26.5 12.8 weeks, p = 0.011). We performed leg lengthening using the Ilizarov fixator in five of 15 patients (min 2 cm, max 8 cm) due to segmental bone defects.
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union (p = 0.003). In contrast, the number of previous operations did not have any effect. Furthermore, patients with a previous local or free tissue transfer did not develop more complications than patients without any tissue transfer. In 21 patients with external fixation where arthrodesis failed, a second arthrodesis was performed during follow-up with a change to intramedullary nailing in 18 cases. Of these cases nine patients achieved osseous fusion (50%) after an average of 29 weeks (22.7; Median 20 weeks). No second arthrodesis was conducted in patients primarily treated with an intramedullary nail. Four patients (5.6%) underwent amputation during follow-up due to recurrent infection. Three of these patients had been treated with an AO frame, and one with an Ilizarov ring fixator.
3.3. Primary and secondary endpoints/follow-up 4. Discussion Average follow-up lasted 18 months (15.92, Median 15 months). Infection was permanently resolved after arthrodesis in 52 cases, whereas re-exacerbation occurred in 19 patients (27%). The nail group had a significantly lower re-exacerbation rate when compared to the external fixator group (nail 5.6% vs. external fixator 34%; p = 0.019) (Fig. 1). Full weightbearing was achieved significantly more often in the nail group (nail n = 16/18, external fixator n = 33/53; p = 0.042). Moreover, full weightbearing was accomplished earlier in the nail group when compared to the external fixator group (22 vs. 51 weeks). Across all three groups, radiological bone fusion was seen in 43 patients (61%) by the end of follow-up (Fig. 2–4). The difference between internal and external fixation was not statistically significant (p = 0.101), although more frequent in the nail group (nail: 78%, external fixator: 55%) (Fig. 5). Furthermore, consolidation was achieved faster in patients with intramedullary nailing (nail: 35 weeks, AO frame: 58 weeks, Ilizarov: 60 weeks). Evidence of multidrug resistant pathogens or a culture with more than two species before arthrodesis were risk factors for failure of osseous fusion in all groups. In the presence of a sole multidrug resistant pathogen, only three out of eleven reached consolidation (27%). In the presence of a bacterial spectrum with at least three different pathogens, nine out of 16 reached osseous fusion (56%). The nail group had significantly fewer complications (p < 0.001) and non-unions (p < 0.001) than the external fixator group (Figs. 1,5). A positive bacterial culture at the time of arthrodesis surgery was associated with postoperative complications as well as non-
Fig. 1. Comparison of rate of complications between AO frame, Ilizarov ring fixator and retrograde intramedullary nail.
External fixation still is considered as the gold standard in septic ankle arthrodesis [1,4,13–17]. Internal and intramedullary procedures are rarely used to avoid implants in the infected bone. Nevertheless, we briefly use retrograde intramedullary nails for septic ankle arthrodesis. The objective of our study is to compare the outcome of external fixation versus retrograde intramedullary nailing for septic ankle arthrodesis. With respect to primary and secondary endpoints, the nail group was superior. Patients in the nail group had significant fewer recurrent infections, achieved full weightbearing significantly more often and faster, and had significantly fewer complications. Moreover, patients in the nail group achieved osseous fusion more often, but this difference was not statistically significant. To our knowledge, our analysis represents the largest patient cohort to date comparing internal and external methods for septic ankle arthrodesis. While there are numerous comparative studies concerning aseptic ankle arthrodesis and studies concerning retrograde intramedullary nailing [7–9,21,23], there are only a few studies about septic ankle arthrodesis (Table 2). Comparative studies are particularly rare [1,3]. A further complicating factor is that the comparability of the existing studies is limited by inconsistent study design, heterogeneous patient collectives, and varying end points [5]. Moore et al. [1] compared internal and external surgical procedures in septic ankle arthrodesis. Both methods achieved similar results concerning limb salvage, final functional status, infection clearance and bony union. However, they analysed a smaller number of cases (n = 32) than we did. Furthermore, the “internal group” included several operative techniques, such as arthrodesis with screws or nail. This variation complicates the comparability. Hulscher et al. [3] also compared external and internal surgical procedures in septic ankle arthrodesis. They included only 19 patients and the internal group was quite diverse once again (screws, plate, k-wire fixation). There were no significant differences between the operative procedures in terms of the fusion rate. Kappler et al. [6] analysed retrograde intramedullary nailing in 49 septic ankle arthrodesis without a control group. 85.7% achieved bony fusion. 10.2% suffered reinfection. In our study, 77.8% of the nail group achieved osseous fusion during follow-up, but only 5.6% suffered reinfection. Richter et al. [5] analysed the results of combined internal and external arthrodesis in 45 patients with septic ankles. The authors mention the high complication rate for external fixation. Other authors also describe a high complication rate for external fixation [3,4,15,17]. There is an increased risk of pin tract infection, even if the patient is compliant with aftercare [7,9,14]. In addition, an external fixator is not convenient for the patient and
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Fig. 2. Ankle arthrodesis with AO frame. (1) Primary osteosynthesis. (2) Distance arthrodesis with AO frame and enclosed gentamycin chains. (3) After removal of the gentamycin chains and final arthrodesis. (4) After removal of the external fixator and bone fusion of the arthrodesis.
Fig. 3. Segmental transport and ankle arthrodesis with Ilizarov fixator. (1) Arthrodesis, distance arthrodesis with Ilizarov fixator and enclosed gentamycin chains. (2) Segmental transport. (3) Increasing formation of new bone proximal and increasing fusion of the ankle arthrodesis. (4) After removal of the Ilizarov fixator with new bone proximal. (5) Consolidation of the ankle arthrodesis.
Fig. 4. Ankle arthrodesis with retrograde intramedullary nail. (1) Primary osteosynthesis. (2) Chronic ankle joint infection with lysis. (3) Ankle arthrodesis with retrograde intramedullary nail. (4) Increasing bone fusion of the arthrodesis. (5) After removing the intramedullary nail: consolidation of the ankle arthrodesis.
makes mobilisation more difficult [3,9]. Full weightbearing is not allowed with the AO frame to prevent loosening of the pins [16]. This consideration does not apply to the Ilizarov ring fixator. Biomechanical studies demonstrated comparable stability
with either a retrograde intramedullary nail, screw arthrodesis or an Ilizarov ring fixator [24,25]. Stability is an important factor for both osseous fusion and permanent infection clearance [1,3,5].
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Fig. 5. Flowchart depicting the rate of bone fusion respective rate of non-union relating to AO frame, Ilizarov fixator and retrograde intramedullary nail.
Table 2 studies concerning septic ankle fusions. No. of septic fusions
Method of fixation
Fusion rate (%)
Reinfection rate (%)
Complication rate (%) (major/ minor)
1999 45 2001 19
45 19
86.6 84.2
20 n.a.
/62 42.1
Kollig Schmidt Saltzman Salem Rochmanb Dalla Paolaa Kovoor Kienast El-Alfy Chen
2003 2005 2005 2006 2008 2009
15 107 8 22 11 45
15 107 8 17 11 45
Internal + External fixation External (8) vs. internal (8) vs. combination (3) Hybrid external fixator External fixation (AO vs. Ilizarov) Ilizarov external fixator Ilizarov external fixator Ilizarov external fixator External fixator
93 86.9 87.5 95 90.9 86.7
20 14 0 17.6 0 8.9
n.a. 27 50 50 54.5 n.a.
2009 2010 2010 2010
20 133 12 12
17 133 7 12
95 91.7 91.7 100
15 4.5 0 0
45 20.3 16.7/75 33
Klouche Gessmann Pawara Kappler Gross Moore Kawoosa Suda
2011 2011 2013 2014 2014 2015 2015 2016
20 37 5 49 30 30 16 79
20 37 5 49 6 32 3 79
Ilizarov external fixator AO external fixator Ilizarov external fixator Combined Ilizarov + intramedullary nailing Screws Ilizarov external fixator Coated nail Retrograde nailing Intramedullary nail Internal vs. external fixation Ilizarov external fixator External fixation
89.5 94.6 100 85.7 86 72 100 85
15 5.4 0 10.2 n.a. 18.8 n.a. 22.8
25 18.9/27 n.a. 14.3 24/56 40.6 0/43.8 60.8
Author
Year
Richter Hulscher
No. of patients
n.a. not available. a Charcot foot and ankle osteomyelitis. b Infection of the Talus, tibio-calcaneal arthrodesis.
Another advantage of the Ilizarov ring fixator is the possibility of segmental transport for leg lengthening [26]. We successfully performed leg lengthening using the Ilizarov fixator in five of 15 patients (min 2 cm, max 8 cm). But viewed as a whole, an external fixator demands a high level of compliance for months — in a non-compliant patient population [1,9]. Moore et al. [1] argue that the negative aspects of external fixators outweigh any potential benefits when compared to internal fixation. The overall reinfection rate after septic ankle arthrodesis is reported as 0–22% in the current literature (Table 2). The results are hard to compare due to differences in study design. In our study, we saw a significant difference in the reinfection rate between the nail group and the external fixator group. The rate of osseous fusion after septic ankle arthrodesis is reported as 69–100% in the current literature (Table 2). The period of time until
radiologically verified bony fusion varies between 4.8 and 8.5 months [1,2,4,13,16]. We found comparable fusion rates in our nail group, but the fusion rate in our external fixator group was worse. The period of time until bony fusion (including primary therapy failures) was comparable to the results of other published studies. The time period until full weightbearing varies between 4 and 7.3 months in the current literature, and in extreme cases, time periods as long as 19 months are reported [3,5,13,16]. All in all, our results are comparable to those in other studies, but our nail group was superior to our external fixator group. Generally satisfactory results for internal procedures in septic ankle arthrodesis are described in the current literature despite implants in the infected bone, but the number of studies and the number of cases are small. Hulscher et al. [3] suggest the need for a consistent, step-bystep approach with eradication of the infection, adequate soft
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tissue coverage and consolidation of the arthrodesis in case of septic ankle arthrodesis. As a rule, we perform successive surgical debridement procedures until we no longer detect any pathogens. Despite such caution, we still found pathogens in the intraoperative biopsies in 31 patients. The extent to which bacterial species and bacterial resistance influence the result remains to be definitively resolved. Whereas Kovoor et al. [27] identify no relevant influence, preoperative positive bacterial cultures with multidrug resistant pathogens or greater than two different species proved to be a risk factor for non-union in our patient population. A major objective of septic ankle arthrodesis is to avoid amputation of the affected leg. In case of persistent infection or unsuccessful arthrodesis, amputation may be unavoidable. The rate of amputation in the current literature varies between 2% and 10.5% [1–3,5,6,15,16]. Four out of 71 of our patients (5.6%) required amputation. All of these patients had received a septic ankle arthrodesis via external fixator. There are some limitations to our study. We cannot exclude selection bias due to the non-randomised study design. In the past, we solely used external fixators for septic ankle arthrodesis. Since we use retrograde intramedullary nailing for septic ankle arthrodesis, the number of patients treated with external fixator decreased continuously. The decision to treatment method was determined individually by surgeons’ preference since 2014. By now we predominantly use intramedullary nails – even in the case of multidrug resistant pathogens or in presence of multiple pathogens – because of good long-term results for nearly five years. Only if retrograde nailing is not possible for technical reasons, we use an external fixator. An Ilizarov ring fixator is still applied, if a segmental bone transport is conducted. However, the internal and the external fixation group were comparable regarding epidemiologic and preoperative data (Table 1). In particular no relevant clinical differences were found concerning number of preoperative multidrug resistance or multiple pathogens (multidrug resistant pathogen: nail 22% vs. external fixator 21%; multiple pathogens: nail 22% vs. external fixator 23%). In both groups arthrodesis was performed only if the last debridement showed sterile microbiological cultures. But the groups are of unequal number of patients with fewer patients in the nail-group. Furthermore, patients in the nail-group have a shorter follow-up period, because we began using this operative procedure for septic ankle arthrodesis only a few years ago. The degree to which the significantly lower reinfection rate in the nail group is the consequence of the shorter follow-up period needs to be evaluated in further follow-up. The overall lower fusion rate in our study compared to other studies may be influenced by the shorter follow-up period, too. Our early results of septic ankle arthrodesis using intramedullary nails are promising, and even better than septic ankle arthrodesis using external fixators with respect to our primary and secondary endpoints. In our opinion, the high stability, which can be achieved with an intramedullary nail is of essential importance for successful treatment, even in the case of a history of sepsis. Further long-term follow-up is necessary. 5. Conclusions In summary, retrograde nailing appears to be a promising alternative to established external arthrodesis procedures in septic ankle arthrodesis – despite the intramedullary location. Radical surgical debridement is required. The high stability is essential. The early weightbearing is advantageous. The disadvantages of external fixation – poor comfort, pin infections, partial weightbearing – do not apply.
Funding This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors. Ethics approval This study was favorably evaluated by the Ethics Committee of Witten/Herdecke University (No. 67/2017). Conflict of interest statement The authors declare, that they have no conflicts of interests or financial conflicts. Consent for publication We obtained informed consent from the analyzed patients. Level of evidence IIIb, retrospective comparative series Registration of clinical trials Registration trial DRKS00014008. Data statement The datasets analysed during the current studyare available from the corresponding author on reasonable request. CRediT authorship contribution statement Matthias Rüschenschmidt: Writing - original draft. Martin Glombitza: Conceptualization. Janosch Dahmen: Investigation, Writing - review & editing. Peter-Michael Hax: Writing - review & editing. Rolf Lefering: Formal analysis, Methodology, Writing review & editing. Eva Steinhausen: Writing - original draft, Conceptualization, Project administration. References [1] Moore J, Berberian WS, Lee M. An analysis of 2 fusion methods for the treatment of osteomyelitis following fractures about the ankle. Foot Ankle Int 2015;36(5):547–55. [2] Klouche S, El-Masri F, Graff W, Mamoudy P. Arthrodesis with internal fixation of the infected ankle. J Foot Ankle Surg 2011;50(1):25–30. [3] Hulscher JB, te Velde EA, Schuurman AH, Hoogendoorn JM, Kon M, van der Werken C. Arthrodesis after osteosynthesis and infection of the ankle joint. Injury 2001;32(2):145–52. [4] Suda AJ, Richter A, Abou-Nouar G, Jazzazi M, Tinelli M, Bischel OE. Arthrodesis for septic arthritis of the ankle: risk factors and complications. Arch Orthop Trauma Surg 2016;136(10):1343–8. [5] Richter D, Hahn MP, Laun RA, Ekkernkamp A, Muhr G, Ostermann PA. Arthrodesis of the infected ankle and subtalar joint: technique, indications, and results of 45 consecutive cases. J Trauma 1999;47(6):1072–8. [6] Kappler C, Staubach R, Abdulazim A, Kemmerer M, Walter G, Hoffmann R. Hindfoot arthrodesis for post-infectious ankle destruction using an intramedullary retrograde hindfoot nail. Unfallchirurg 2014;117(4):348–54. [7] Buchner M, Sabo D. External or internal fixation for arthrodesis of the ankle – a comparative study of perioperative and long-term results. Unfallchirurg 2003;106(6):472–7. [8] Muckley T, Schutz T, Srivastava S, Goebel M, Gonschorek O, Buhren V. Ankle arthrodesis with intramedullary compression nailing. Unfallchirurg 2003;106 (9):732–40. [9] Easley ME, Montijo HE, Wilson JB, Fitch RD, Nunley JA. 2nd. Revision tibiotalar arthrodesis. J Bone Joint Surg Am 2008;90(6):1212–23. [10] Zwipp H, Rammelt S, Endres T, Heineck J. High union rates and function scores at midterm followup with ankle arthrodesis using a four screw technique. Clin Orthop Relat Res 2010;468(4):958–68. [11] Jerosch J. Arthroscopic in situ arthrodesis of the upper ankle. Orthopade 2005;34(12):1198–208.
Please cite this article in press as: M. Rüschenschmidt, et al., External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study, Foot Ankle Surg (2019), https://doi.org/10.1016/j.fas.2019.05.001
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Please cite this article in press as: M. Rüschenschmidt, et al., External versus internal fixation for arthrodesis of chronic ankle joint infections — A comparative retrospective study, Foot Ankle Surg (2019), https://doi.org/10.1016/j.fas.2019.05.001