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 Table of Contents  
ORIGINAL ARTICLE
Year : 2015  |  Volume : 1  |  Issue : 1  |  Page : 14-20

Fixator-assisted nailing for revision ankle fusion with deformity, bone loss and or infection


1 Monash University; Centre for Limb Reconstruction; Epworth Health Care, Melbourne, Australia
2 Centre for Limb Reconstruction; Epworth Health Care, Melbourne, Australia

Date of Submission18-Oct-2015
Date of Acceptance30-Oct-2015
Date of Web Publication5-Nov-2015

Correspondence Address:
Minoo K Patel
Suite 5 7, The Epworth Centre, 32 Erin Street, Richmond VIC 3121
Australia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2455-3719.168744

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  Abstract 

Context: Ankle nonunions with deformity and bone loss are challenging cases, often with broken hardware and infection. These cases are often associated with multiple previous surgeries making revision surgery difficult. Ankle fusion for failed total ankle arthroplasty or neuropathic joints are particularly challenging, which is reflected in high reported failure rates.
Aims: Fixator-assisted nailing combines Taylor spatial frame (TSF) with an intramedullary nail, allowing for correction of deformity and compression at the nonunion site, as well as internal fixation protecting the fusion after frame removal.
Subjects and Methods: Between 2001 and 2014, 24 patients with 26 failed ankle fusions, with bone loss and deformity, were treated using this technique. After removal of the original internal fixation hardware and revision of the fusion surfaces, a Taylor frame is used for acute or gradual correction of deformity and compression at the nonunion site. This was followed by insertion of intramedullary nail. The nail was locked at the time of fixator removal.
Results: Acute correction was possible in 23 of the 26 cases with gradual correction in the others. Union was obtained in 25 cases (96.2%) and maintained at 24 months in 23 cases (88.4%). The overall salvage rate (avoidance of amputation) was 96.2% (25/26 cases). All salvaged limbs remain free of clinical infection and do not require ongoing antibiotic treatment. The foot was in neutral position in all salvaged cases. The average time in external fixation was 11 weeks (6-13 weeks). The average AOFAS ankle/hindfoot score was 74 (range: 61-80).
Conclusions: Fixator-assisted nailing, combining a TSF and an intramedullary nail, is a reliable technique for revision ankle fusion for complex nonunion with deformity and/or infection.

Keywords: Complex ankle fusion nonunion, fixator-assisted nailing, revision ankle fusion


How to cite this article:
Patel MK, Mannambeth RV. Fixator-assisted nailing for revision ankle fusion with deformity, bone loss and or infection. J Limb Lengthen Reconstr 2015;1:14-20

How to cite this URL:
Patel MK, Mannambeth RV. Fixator-assisted nailing for revision ankle fusion with deformity, bone loss and or infection. J Limb Lengthen Reconstr [serial online] 2015 [cited 2019 Jul 18];1:14-20. Available from: http://www.jlimblengthrecon.org/text.asp?2015/1/1/14/168744


  Introduction Top


Ankle fusion is a reliable operation; however nonunion often occurs especially with neuropathic joints and in the presence of infection. [1],[2],[3],[4],[5],[6],[7] Ankle fusion nonunions with deformity and bone loss, often with broken hardware and infection, are challenging cases. Multiple previous surgeries make revision surgery difficult. Ankle fusion for failed total ankle arthroplasty or neuropathic joints are particularly challenging, which is reflected in high reported failure rates.

Good fixation is often difficult with traditional plates, screws or intramedullary devices. Often the skin and soft tissues are of poor quality due to previous surgery, infection, and comorbidities such as diabetes or inflammatory arthritis. Large incisions for deformity correction or bulky plate fixation are prone to wound healing problems. In addition, previous implants, often broken, need to be removed prior to the insertion of new implants.

While intramedullary nails can be inserted by minimally invasive means, they offer poor torsional stability especially in the early stages of fusion.

Both intramedullary nails and plates face difficulties with bone loss especially distally, with poor bone stock in the talus and or calcaneus.

The key to achieve ankle fusion is compression across the fusion site. Nails and plates offer limited ability to obtain compression across the fusion site. Newer nails that offer the ability to compress after the insertion of interlocking screws are limited in the amount of compression that can be obtained. Furthermore, any compression across the fusion site is static and cannot be altered during the postoperative period. Dynamization is not a reliable option with retrograde nails for ankle fusion.

Ilizarov surgery allows for deformity correction, management of infection, and revision fusion. [8],[9],[10],[11],[12],[13],[14],[15] The deformity correction can be acute on the operating table or gradual using the frame.

Fine wire frames can gain better purchase in osteopenic bone. Incorporation of foot in the frame neutralizes the apex posterior forces which often result in implant loosening.

The fusion surfaces can be revised through small incisions, often through better quality tissue away from previous incisions. The Ilizarov or Taylor frame is applied percutaneously. The deformity can be corrected acutely with accurate reduction of fusion surfaces. The fixator can then be used to compress across the fusion site.

Alternately, Taylor frame can be used to gradually correct the deformity. This often the case with very stiff soft tissues.

Non impinging broken implants can be left in situ if they do not interfere with fusion surface revision, deformity correction, and compression.

Using an intramedullary nail in conjunction with the Taylor frame allows for decreased time in external fixation. [16] The nail also acts as an internal splint after the external fixator is removed protecting the fusion. This prevents delayed failure or re-fractures through the fusion site.

In this paper, we present or 15 years of experience from 2001 to 2014 in dealing with these cases. We have combined the use of external fixation with intramedullary fixation to obtain and maintain ankle fusion in these difficult cases.


  Subjects and Methods Top


Between 2001 and 2014, 24 patients with 26 failed ankle fusions, with bone loss and deformity, were treated at our center. The clinical records and radiographs were reviewed from the electronic medical records.

Comorbidities included 17 cases with diabetes, 5 with inflammatory joint disease, renal impairment in 5 cases and peripheral vascular disease in 10 cases. Four patients were smokers. Four cases were immunocompromised due to drug therapy or secondary to renal failure. Some patients had multiple comorbidities [Table 1].
Table 1: Comorbidities associated with patients (some patients had multiple comorbidities)


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The indication for the failed primary ankle fusion, as obtained from previous operation records, was osteoarthritis in 5 cases, inflammatory joint disease in 3 cases, Charcot-Marie-Tooth disease in 1 case, conversion from ankle arthroplasty in 5 cases, diabetic neuropathy of the ankle in 8 cases, and septic arthritis and alcoholic neuropathy in 1 case each. Of the failed total ankle arthroplasty cases, three had arthroplasty for osteoarthritis and two for inflammatory joint disease. Seventeen cases had one prior surgery, 3 cases two prior surgeries, 2 cases three prior surgeries, 4 cases four or more surgeries. Twelve feet had active, and four had nascent infection. Ten cases had aseptic nonunion [Table 2]. Two patients had bilateral ankle fusion nonunions, one of whom had osteoarthritis as the primary indication for fusion and the other inflammatory joint disease as the primary indication [Table 3].

Of the 24 cases, 12 were males and 12 females. Both cases with bilateral ankle involvement were female. The average age of patients was 68 years (range: 61-79).
Table 2: Number of previous surgeries prior to revision fusion


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Table 3: Indication for the primary (failed) ankle fusion


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All patients had a hind foot fusion, with 7 cases of tibio-calcaneal fusion due to talus destruction and the rest having a tibio-talo-calcaneal fusion.

The deformity was assessed with plain X-rays and computed tomography scans. Tc-99 bone scans and magnetic resonance imaging scans were done assess infection when suspected. Infected cases were commenced on antibiotics.

Surgical technique

  • Step 1 - Hardware removal and preparation

    Hardware was removed as necessary. Necrotic and infected bone was debrided. Debridement was conservative to preserve bone stock. The fusion surfaces on the tibia, talus, and calcaneus were revised with an oscillating saw and osteotome.


  • Step 2 - Application of ring fixator

    The Taylor spatial frame (TSF, Smith and Nephew, Memphis, TN, USA) was applied using a tibial full ring and a foot ring. The tibial ring was usually fixed with one wire and two hydroxyapatite-coated half-pins, 18 cm proximal to the ankle joint line, to accommodate a retrograde ankle fusion nail [Figure 1].
    Figure 1: (a and b)Intraoperative photograph showing the insertion of the retrograde intramedullary nail with the Taylor spatial frame applied to the ankle. Acute correction of the ankle has been obtained allowing for initial compression at the nonunion site and insertion of the intramedullary nail. Note how the adjustable jig for insertion of distal interlocking screws can be slipped between the foot and the foot ring of the Taylor spatial frame. The two calcaneal wires (crossed olive wires) are posterior to the line of the intramedullary nail

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    The foot ring was applied with two calcaneal crossed olive wires and two forefoot wires. The calcaneal wires were applied to get a wide 90° spread, allowing for the placement of the retrograde nail [Figure 1] [Figure 2] [Figure 3].
    Figure 2: Case with infected nonunion of ankle fusion with talus destruction. The original surgery was a total ankle replacement for sero-negative inflammatory joint disease. Infection of the ankle arthroplasty was salvaged with an ankle arthrodesis which resulted in an infected nonunion which was revised using fixator-assisted nailing. (a) The discharging sinus. (b and c) (Video 1) The three-dimensional computed tomography scan images of the ankle. (d) Is a radiograph of the fixator-assisted nailing? and (e) the final radiograph

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    Figure 3: (a-h) Case of a 67-year-old patient with rheumatoid arthritis with a nonunion of ankle fusion performed with a blade plate device with varus deformity at the ankle as seen in Figure 3a and b and in radiographs (c and d). Nonunion was suspected on computed tomography scan and confirmed under image intensifier after removal of the internal fixation hardware. (e) The Taylor spatial frame with intramedullary nail in situ. The final radiographs are as seen in Figure 3 (f-h). Note the total knee replacement proximally as seen in Figure 3 (e and h). The presence of replacement arthroplasty is not considered a contraindication for the use of an external ring fixator or a retrograde nail

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  • Step 3 - Correction of deformity

    In most cases, the deformity was able corrected manually under image intensifier, and the TSF struts locked into place. Often the TSF computer program was used to fine tune the correction, in particular 3-5 mm posterior translation of the talus or 5-7 mm translation of the calcaneus (if the talus was absent), to improve the foot position, to allow for better push-off in the presence of a stiff hind foot. Gradual correction was required in one of two settings: (1) when the soft tissue stiffness and scarring precluded acute correction, or (2) when acute shortening at the fusion site caused the skin to buckle especially with a linear incision. Gradual correction was performed over 7-10 days using the TSF computer program.


  • Step 4 - Insertion of the intramedullary nail [Figure 1] [Figure 2] [Figure 3]

    In most cases, an acute correction of the deformity was followed by the insertion of retrograde nail. Phoenix ankle fusion nail (Biomet, Warsaw, IN, USA) was used through a plantar calcaneal insertion site. An adaptor was used to allow the use of the older jig that would slide under the foot ring, posteriorly and medially to allow for distal interlocking screw insertion. In cases when gradual correction of the deformity was necessary, the retrograde nail was inserted after the correction of the deformity and initial compression as in Step 5 [Figure 1] [Figure 2] [Figure 3].


  • Step 5 - Compression with the ring fixator

    The fusion site was compressed with the TSF computer program over next 4 weeks. During this period, the patient was allowed to ambulate bearing full body weight as tolerated.


  • Step 6 - Locking of the intramedullary nail and removal of the external fixator.

    The nail was locked with the insertion of proximal interlocking screws. These were inserted freehand using image intensifier [Figure 2] and [Figure 3]. In cases requiring gradual correction, the nail was either inserted at the end of deformity correction, but prior to compression with the ring fixator, or inserted after compression with the fixator.

  Results Top


Acute correction was possible in 23 of the 26 cases. In 1 case, the intramedullary nail was inserted after deformity correction, at the 2 weeks mark, and compression continued with the external fixator, following which the nail was locked proximally. In 2 cases, the nail was inserted after deformity correction and compression, at the time of fixator removal.

Union was obtained in 25 cases (96.2%) and maintained at 24 months in 23 cases (88.4%).

One case required revision fusion 24 months after the first fixator-assisted nailing, due to loosening of the proximal interlocking screws and re-fracture of the fusion site. The ankle united after the second procedure and union has been maintained. One case had severe recurrence of infection after worsening of immunosuppression, 36 months after revision fusion, resulting in nail loosening. The infection was not able to be controlled and on the advice of the medical team an amputation was performed.

One case had a painless nonunion and preferred to ambulate with a protective boot till her death 5 years after the surgery.

In 20 of the 26 cases, amputation was offered by other surgeons but declined by the patient.

The overall salvage rate (avoidance of amputation) was 96.2% (25/26). All salvaged limbs remain free of clinical infection and do not require ongoing antibiotic treatment. The foot was in neutral position in all salvaged cases. Twenty-three patients (25 ankles) returned to independent home living. One patient who required below the knee amputation is now wheel chair dependent and in high level care due to poor mobility.

The average time in external fixation was 11 weeks (6-13 weeks). The average American Orthopaedic Foot and Ankle Society (AOFAS) ankle/hindfoot score was 74 (61-80). The highest attainable score with tibio-talo-calcaneal fusion is 86.

The average limb shortening was 1.6 cm (0.5-2.4 cm). No case required tibia lengthening, with the patients opting for a minor or no shoe raise.

Complications

There were 12 wire or pin site infection, 3 of which required wire or pin exchange. One case developed recurrence of regional pain syndrome, which settled after 6 months.

One case required nail removal due to prominence of the nail on the sole of the foot. This was a case with tibio-calcaneal fusion. Two cases developed a stress fracture at the tip of the nail, within 12 months of the surgery. One was treated in a cast brace. The nail was exchanged for a long ankle spanning antegrade tibia nail in 1 case.

One case required bone grafting and one an implantable bone stimulator, both for aseptic delayed union.


  Discussion Top


Nonunion of ankle fusion remains a difficult problem, especially in the setting of infection and neuropathic foot. Fragomen et al. achieved fusion in 76 of 91 primary cases. [11] Bernstein et al. reported nonunion rates of 7.6%, fracture rates of 1.4%, and amputation rates of 4.7% in a meta-analysis of ankle fusion for neuropathic ankles. [17] Salvage rates are worse still with infection [8],[16],[18],[19] and neuropathic arthropathy. [10],[12],[16],[17],[20],[21],[22],[23],[24],[25]

Most authors reported the use of plates, intramedullary nails, or external fixation in isolation. [8],[10],[12],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25] In our opinion, the two main prerequisites for obtaining ankle fusion are stability and compression. One follows the other. Plating systems, including locking plates and fixed angled blade plates, cannot offer adequate angular or torsional stability. Intramedullary devices also offer poor torsional stability. None of the intramedullary ankle fusion nails offer locked screws, unlike humerus or tibia nails.

We attribute our better salvage rate of 96.2% to a combination of external fixation and intramedullary nailing. Various authors have reported on the use of Ilizarov external fixation for revision ankle fusion; none used fixator nailing. [2],[4],[6],[26],[27],[28] Using a ring fixator with an intramedullary nail, we are able to combine the best attributes of both devices. The ring fixator achieves good fixation, even in osteopenic bone. The intramedullary nail acts as a guide rail around which to compress the fusion surfaces. When using an external fixator alone, once the fixator is removed at the end of the treatment the fusion is unprotected. This was the case with three of the patients in our series that had had previous treatment with an external fixator. In two of our cases, loosening of the nail with recurrent infection resulted in delayed failure of the fusion. While it could be argued that these 2 cases had nonunion of their ankle fusion at the time of removal of external fixation and locking of the intramedullary nail, union was confirmed on radiographs and both patients were able to ambulate bearing full body weight, before the delayed failure of the fusion at 12 months in 1 case and 24 months in the other.

Combining internal and external fixation allows for reduction of time spent in external fixation in cases of distraction osteogenesis. The same is true for ankle fusion surgery.

In Fragomen's study with primary arthrodesis, the average time in external fixation was 25 weeks. [11] By contrast, even in revision ankle fusion, we were able to cut down the time spent in external fixation to 11 weeks using an intramedullary nail in conjunction with external fixation.

Eralp et al. reported using fixator-assisted nailing and lengthening or transport over a nail for distal tibia excision for osteomyelitis with ankle fusion in a small series of 7 cases. However, none of these cases were of revision ankle fusion. Jeong et al. reported a single case of revision neuropathic ankle fusion with external fixation and avascular fibular graft used intramedullary. [29] This technique risks infection in the avascular bone graft. The fibula strut has poor mechanical strength compared to a locked nail and involves additional surgery.

It is noteworthy that 20 of the 26 patients had been offered an amputation. One of the main reasons for refusal to have an amputation was the fear of not being able to walk again, even with a light weight prosthetic limb. These patients were elderly and had multiple comorbidities, with poor rehabilitation prospects with a below the knee amputation. Indeed, the only patient in this series to require an amputation is now wheelchair dependent and consequently in high level care. In contrast, all other patients returned to independent home living.


  Conclusion Top


Fixator-assisted nailing for nonunion of ankle fusion gives good results even in the presence of infection and foot neuropathy. Using an intramedullary device in conjunction with external fixation reduces time in external fixation, without increasing infection rates.

Financial support and sponsorship

Institution funding for a fellowship program at Epworth Healthcare, Melbourne from Kleos Foundation, Smith and Nephew, Australia.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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2.
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27.
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29.
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    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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