Ankle Arthrodesis Using Ring External Fixation - Orthofix.com

Techniques in Foot and Ankle Surgery 5(3):150–163, 2006 Ó 2006 Lippincott Williams & Wilkins, Philadelphia 

. S P E C I A L F O C U S . 

Ankle Arthrodesis Using Ring External Fixation 

Mark Easley, MD, Colin Looney, MD, Samuel Wellman, MD, and Joseph Wilson, MD 

Division of Orthopaedic Surgery 

Duke University Medical Center 

Durham, NC 

| ABSTRACT 

Contemporary recommendations for primary and revision 

ankle arthrodesis favor internal compression techniques 

using screw and/or plate fixation, with satisfactory outcomes 

being reported for most patients. Recently, comparable 

union rates and results of primary and revision 

tibiotalar arthrodeses have been reported using ring external 

fixation. In select patients, tibiotalar arthrodesis with 

internal fixation may be limited or even contraindicated 

given insufficient bone stock to adequately support 

implants, an abundance of avascular bone, or a history of 

osteomyelitis. Ring external fixation may facilitate clinically 

acceptable limb salvage in these complex cases. This 

review paper describes the authors’ experience using ring 

external fixation for ankle arthrodesis. 

Keywords: ankle, arthrodesis, external fixation, multiplanar, 

Ilizarov 

| HISTORICAL PERSPECTIVE 

Many advances have been made in the past 2 decades in 

the management of advanced tibiotalar arthritis unresponsive 

to nonoperative treatment. Although ankle arthroscopy, 

distraction arthroplasty, fresh allograft shell 

reconstruction, supramalleolar osteotomy, and total ankle 

arthroplasty have shown promise in select cases of advanced 

ankle arthritis, ankle arthrodesis remains the criterion standard 

surgical management. Results of ankle arthrodesis using 

internal fixation for stability and compression are consistently 

favorable, 1,2 and internal fixation for ankle arthrodesis 

is the technique of choice in most cases. However, 

surgeons and patients are occasionally confronted with 

ankle arthritis that should be managed with arthrodesis but 

does not lend itself well to internal fixation. External 

fixation represents an attractive alternative in such 

situations. Although external fixation for problems of the 

foot and ankle is not universally taught in orthopedic 

training programs, it has been used routinely for numerous 

disorders of the foot and ankle in select medical centers 

worldwide. Gradually, the number of surgeons applying 

Address correspondence and reprint requests to Mark Easley, MD, 

Duke Health Center, 3116 North Duke Street, Rm 243, Durham, 

NC 27704. E-mail: easle004@mc.duke.edu. 

150 

Techniques in Foot and Ankle Surgery 

the techniques developed in these institutions for the 

surgical management of foot and ankle disorders is 

increasing, either by necessity or by recognition of the 

advantages of these methods in select foot and ankle 

problems. Although results of ankle arthrodesis using external 

fixation are not as widely published as those using 

internal fixation, the results of ankle arthrodesis using 

external fixation, even in revision surgery, are favorable. 

| INDICATIONS AND 

CONTRAINDICATIONS 

The most common indication for ankle arthrodesis is 

severe, destructive arthritis that fails nonoperative management, 

most commonly posttraumatic in origin. Less 

frequently, ankle arthritis is caused by primary or inflammatory 

arthropathy. Currently, severe ankle arthritis 

can be managed with total ankle replacement 3 or fresh 

allograft reconstruction, 4 but ankle arthrodesis remains 

the procedure against which all others are measured. 

Regardless of the method of fixation, ankle arthrodesis 

is contraindicated in patients with peripheral vascular 

disease until adequate circulation for healing can be 

reestablished. Absolute indications for arthrodesis 

include ankle arthritis associated with neuropathy, avascular 

necrosis of the talus or distal tibia, severe coronal or 

sagittal plane deformity, and nonreconstructable ankle 

ligament insufficiency. That is to say, in such cases, total 

ankle replacement is contraindicated. Joint-sparing procedures 

may be favored when ankle arthritis is associated 

with ipsilateral hindfoot arthrosis or a contralateral 

tibiotalar/tibiotalocalcaneal arthrodesis. 

Typically, ankle arthrodesis can be effectively performed 

with internal fixation. External fixation may confer 

advantages over internal fixation in several situations. 

Specifically, external fixation for ankle arthrodesis may 

be considered with 1) a history of sepsis/osteomyelitis 

(Figs. 1A, B); 2) a compromised soft tissue envelope about 

the ankle; 3) inadequate bone stock at the arthrodesis site 

to support internal fixation limited to the tibia and talus; 

4) a leg length discrepancy that is inadequately treated 

with a shoe modification; 5) failed prior ankle arthrodesis 

using internal fixation; and 6) anticipated noncompliance 

with a nonYweight-bearing/touchdownYweight-bearing 

Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

Special Focus: Ankle Arthrodesis Using Ring External Fixation 

FIGURE 1. A and B, Ankle arthrodesis using external fixation should be considered in septic ankle arthritis. 

status. Relative contraindications to external fixation for 

ankle arthrodesis are patients with total joint arthroplasties 

(pin tract infections may lead to infection of the joint 

replacement) and neuropathy of the contralateral leg 

(external fixator may inflict wounds in the contralateral 

lower extremity without the patient recognizing it). 

| PREOPERATIVE PLANNING 

History, clinical evaluation, and routine ankle radiographs 

establish the diagnosis of symptomatic tibiotalar arthritis. 

Weight-bearing radiographs of the ankle usually confirm 

the diagnosis. The soft tissue envelope about the ankle and 

the vascular status must be evaluated. Poor soft tissues 

about the ankle (affected by trauma and/or prior surgery) 

typically necessitate a less invasive exposure for joint 

preparation. Compromised perfusion of the extremity 

should prompt vascular consultation to optimize the 

chance for union and proper soft tissue healing. 

Routine weight-bearing ankle radiographs generally 

suffice, but if there is any suspicion on clinical evaluation 

for limb malalignment or foot pathology, then 

mechanical axis, hip and knee, and foot radiographs 

should also be evaluated. Computed tomography (CT) 

and magnetic resonance imaging (MRI) are not routinely 

required. In select cases, CT may help identify 

hindfoot arthritis/deformity if plain radiographs of the 

foot and ankle fail to adequately reveal these clinical 

findings. MRI should be considered if avascular 

necrosis of either the tibial plafond or talus is suggested 

by the radiographs; this may dictate how much bone 

resection is required at the arthrodesis site to access 

vascular surfaces for fusion. 

Simply placing a tibiotalar arthrodesis in neutral 

plantarflexion/dorsiflexion, slight hindfoot valgus, and 

slight external rotation will typically create a functional, 

plantigrade foot. However, disregard for whole limb and 

foot alignment may lead to a poor functional outcome, 

despite successful ankle fusion. Limb malalignment may 

need to be addressed before or simultaneous to ankle 

arthrodesis. An advantage with external fixation is that 

simultaneous combined procedures can be performed, 

such as proximal tibial corticotomy with lengthening/ 

realignment and ankle arthrodesis or concomitant ankle 

and foot procedures. 

When arthrodesis is planned in the face of infection, 

preoperative evaluation includes complete blood cell 

FIGURE 2. A support under the calf facilitates positioning 

of the external fixator. The surgeon must ensure that 

when the support is removed, the proximal ring does not 

impinge on the calf. 

Volume 5, Issue 3 151 


FIGURE 3. External fixation alone does not create 

fusion; proper joint preparation is necessary. 

count with differential and blood cultures. Consideration 

may be given to a MRI or a combination technetium bone 

scan/indium-labeled white blood cells scan to confirm/ 

evaluate the extent of infection, keeping in mind that 

peripheral vascular disease and antibiotics will interfere 

with the effectiveness of these studies. To obtain useful 

intraoperative cultures, antibiotics should be stopped at 

least 3 days before surgery. Planning should include the 

potential for a staged procedure. Irrigation and debridement, 

hardware removal, and possible antibiotic bead 

placement should be planned as the first stage. If the ankle 

is determined to be unstable at that time, the external 

fixator should be placed for support. In a second stage, the 

antibiotic beads can be removed, the ankle again debrided, 

and compression may be applied through the ankle if there 

is no evidence of persistent infection. Alternatively, the 

FIGURE 4. Ideal position for arthrodesis: neutral sagittal 

plane (plantigrade foot), slight hindfoot valgus, tibial shaft 

axis aligned with the second metatarsal, and no anterior 

talar translation within the ankle mortise. This is particularly 

important if a prebuilt frame is applied. 

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Special Focus: Easley et al 

plan can be for a single-stage procedure if the surgeon is 

satisfied that all of the infected tissue has been removed. 

| TECHNIQUE 


A proximal regional anesthetic typically suffices for 

ankle arthrodesis using external fixation. Tourniquet use 

is generally limited to the approach for tibiotalar joint 

preparation. External fixation in itself cannot create a 

fusion; proper joint preparation is essential. Therefore, 

if there is any concern for the perfusion of either the 

tibial plafond or (more likely) the talar dome, then the 

tourniquet must be released before wound closure to confirm 

bleeding at the arthrodesis site. There is no need for 

tourniquet use during application of the external fixator. 

The patient is positioned supine, often with a support 

under the hip of the operated leg. The goal is to orient the 

lower leg directly perpendicular to the operating room 

table/floor to facilitate proper placement of the external 

fixator. A sterile proximal calf support (Bbump^) (Fig.2) 

should be created to suspend the lower leg during 

external fixator placement. 

FIGURE 5. A and B, Intraoperative fluoroscopy in 2 

planes confirms proper alignment. In this case, provisional 

pin fixation was used. 


FIGURE 6. The proximal ring block for tibial fixation. 


The lower leg is prepared and draped in usual sterile 

fashion, and the leg is exsanguinated using a tension 

bandage (unless persistent infection is suspected). The 

tibiotalar joint is approached and prepared using the 

surgeon’s preferred technique (Fig. 3). If there is any 

concern that the arthrodesis site may not maintain the ideal 

position for fusion (Fig. 4), then provisional fixation 

should be used. Although violation of the subtalar joint in 

a patient undergoing isolated tibiotalar joint arthrodesis 

in not ideal, one simple method of maintaining provisional 

fixation is a longitudinal Steinmann pin from the 

calcaneus into the talus. This pin is placed similar to the 

guide pin used for retrograde intramedullary nail procedures 

(Figs. 5A, B). Provisional fixation should maintain 

adequate reduction of the prepared talus within the 

prepared ankle mortise. Optimal function and potential 

for fusion is established with maximum contact between 

the arthrodesis surfaces, avoiding anterior translation of 

the talus within the ankle mortise. Valgus is generally 

established in the hindfoot; varus malalignment at the 

tibiotalar joint must be avoided. Furthermore, calcaneus 

or equinus positioning must be corrected to a neutral 

sagittal plane alignment. Finally, the second metatarsal 

should be in line with the tibial crest to ensure proper 

rotational positioning. After proper joint preparation and 

positioning, the wound can be closed in routine fashion. 

We recommend closing the wound before applying the 

external fixator because access to the wound becomes 

challenging with the external fixator in place. A drain 

may be used, but it must be positioned so that it does not 

interfere with ensuing pin placement. 

Most external fixators have several consistent components: 

1) a proximal ring or proximal ring block (Fig. 6), 

2) an intermediate ring or connector, and 3) a foot ring or 

frame. The proximal ring/ring block usually consists of 1 

or 2 rings attached to the distal tibia. The intermediate 

ring serves to support thin wires secured to the talus. The 

foot frame connects directly to the hindfoot, and in most 

constructs, to the midfoot and forefoot as well. The individual 

components are secured to their respective bones 

using either thin wires (Bskinny wires^) orhalfpins.The 

components of the external fixator are attached to one 

another by threaded rods, adjustable struts, or sockets. 

The connectors between the components that span the 

tibiotalar joint must be able to compress. 

The external fixator can be constructed and applied 

in 2 basic ways: 1) preassembled and applied en bloc 

or 2) step-by-step assembly as it is applied on the 

patient. Theoretically, prebuilding the external fixator 

may save some time and guarantees a symmetrical 

frame construct, with limited modifications to connect 

FIGURE 7. A, Prebuilt Sheffield 

frame (Orthofix) with proximal 

ring/Sheffield clamp, intermediate 

two-thirds rings for talar 

fixation, and foot frame. B, Traditional 

Ilizarov frame with proximal 

extension to allow for 

simultaneous limb lengthening. 



FIGURE 8. One to 2 cm must be maintained between the 

posterior heel and the foot frame. 

the various rings (Figs. 7A, B). Moreover, if the prebuilt 

external fixator has been symmetrically assembled, it 

serves as a template for proper lower leg and foot 

alignment. One challenge with a prebuilt frame is that it 

may be difficult to position both the proximal rings 

orthogonally with the tibia and the foot frame 

(Bhorseshoe ring^) parallel with the foot. 

Alternatively, if the external fixator is assembled in 

a stepwise manner, the proximal ring block is traditionally 

attached first. The foot frame is then applied, along 

with an intermediate ring or connection for the talar 

wires. Lastly, the proximal ring block is connected to the 

distal (foot and talar) construct. In assembling the frame 

in this graduated fashion, it may be useful to place 

threaded rods longitudinally from the proximal to distal 

construct to facilitate proper positioning of 3 or 4 threaded 

FIGURE 9. The foot should be plantar to the foot frame. 

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FIGURE 10. Foot positioned symmetrically within the 

foot frame. 

rods that will ultimately be used for compression across 

the arthrodesis site. 

There are several technique tips that facilitate appropriate 

ring application and typically avoid intraoperative 

fixator revisions: 

1. Allow adequate space for the calf so that the proximal 

ring does not impinge on the soft tissues. One common 

FIGURE 11. To facilitate proper foot positioning within 

the foot frame, the forefoot wire can be placed first to 

suspend the foot. This helps ensure that the heel does 

not contact the foot frame, and subtle adjustments to the 

foot position are still possible. 


mistake is to attach the proximal ring with the bump 

behind the calf to suspend the leg and no regard for 

where the calf will be once the bump is removed. If not 

assessed proactively, the ring will impinge on the calf, 

necessitating removal of the ring and potential repositioning 

of thin wires/half pins (Fig. 2). 

2. Allow adequate room between the posterior heel and 

the foot frame. This space does not need to be more 

than 1.5 cm, as virtually no swelling occurs directly 

posteriorly at the calcaneus, irrespective of how 

extensive the surgery is. However, with direct contact 

of the foot frame to the calcaneus, the external fixator 

potentially may need to be disassembled and 

remounted in its entirety (Fig. 8). 

3. Be sure the foot is plantar to the foot frame. The 

plantar foot pad is thicker than it appears, and if the 

foot frame is positioned too low, it will not be 

possible to pass the thin wires through the bones of 

the foot, only the plantar soft tissues. Poor foot frame 

positioning may again necessitate disassembly of a 

major portion of the entire construct (Fig. 9). 

FIGURE 13. The thin wires in the foot are tensioned. 


FIGURE 12. The calcaneus is stabilized with 2 oblique 

thin wires. 

Applying a Prebuilt External Fixator 

We do not suggest that a prebuilt external fixator is the 

favored method for ankle arthrodesis using external 

fixation, but particularly for the surgeon inexperienced 

with traditional techniques of external fixation, this method 

may facilitate the procedure. After satisfactory joint 

preparation, this sequence of steps could be considered. 

1. Provisional pin fixation of the arthrodesis site. 

2. Intraoperative fluoroscopy to confirm satisfactory 

position of the tibiotalar arthrodesis site (Figs. 5A, B). 

3. Support under the calf (Fig. 2). 

4. Positioning of the prebuilt external fixator (Fig. 2). 

5. Position the foot frame portion symmetrically about 

the foot, avoiding contact between the posterior heel 

and the foot frame (Fig. 10). 

6. Next, thin wires and half pins are added to the 

construct. For ankle arthrodesis, thin wires are smooth, 

and there is no need to use olive wires. Both thin wires 

and half pins should be inserted without tensioning the 

skin. Cold water or saline irrigation or a moist sponge 

to gently hold the thin wire should be used to cool the 

wire during insertion. Once the thin wire has exited the 

opposite cortex, a mallet should be used to complete 

the insertion. Half pin insertion requires a small stab 

incision; thin wires can be placed directly through the 

skin without an incision. 

7. Suspend the foot frame from a single wire or 2 forefoot 

wires (Fig. 11). Traditional positioning of forefoot 

wires is 1 wire through the first and second 

metatarsals and the second wire through the fifth 

through the third metatarsals. This orientation is safe 

and stable, but necessitates that the wires extend 

above and below the frame, which may make weightbearing 

more difficult. Alternatively, a single forefoot 

wire can be placed from the fifth metatarsal to the 

first. This wire is usually placed obliquely to the foot 

FIGURE 14. Proximal ring fixation, in this case, using 

half pins. 



FIGURE 15. A and B, A supplemental half pin in the calcaneus is optional. 

frame and often needs to be connected off the medial 

side using a post (extended connector) to avoid 

excessive plantar flexion of the first ray. 

8. Two oblique calcaneal wires are placed (Fig. 12). 

9. A fourth thin wire is placed in the midfoot/forefoot. 

10. The foot wires are tensioned. If there is an open foot 

frame construct (open distally), then the forefoot 

wires need to be tensioned before the calcaneal wires 

to ensure that tension is maintained in all foot wires 

(if the calcaneal wires are tensioned before the 

forefoot wires are tensioned, the calcaneal wires 

may lose tension, depending on the inherent stiffness 

of the foot frame) (Fig. 13). 

11. With the foot frame securely applied to the foot, the 

proximal ring block is secured to the tibia. Although 

provisional fixation remains across the tibiotalar 

joint, subtle adjustments are still possible (ie, 

slightly greater dorsiflexion or a shift in rotation 

can be accomplished). The proper proximal ring 

position can be maintained with a transverse thin 

wire that is tensioned. Proximal ring fixation can be 

performed solely with the use of thin wires, as 

originally described, but half pins are also an option 

(Fig. 14). Many different combinations of pins are 

possible. Generally, when a single tibial ring is 

used, a clamp that supports 2 half pins in the medial 

face of the tibia is attached to the superior portion of 

the the ring, and a clamp that supports 1 additional 

pin in the anterior tibia is suspended from the 

inferior portion. When using 2 proximal rings, at 

least 1 half pin is attached to each ring into the 

medial face of the tibia, and at least 1 additional pin 

is clamped to either ring in another plane. 

12. Consideration may be given to a supplemental half 

pin placed posterior to anterior in the calcaneus and 

attached to the foot frame (Figs. 15A, B). 

13. With the thin wires properly tensioned and the half 

pins adequately secured, compression can now be 

applied across the tibiotalar arthrodesis site. In a 

patient with a prior subtalar fusion, compression 

FIGURE 16. A and B, Talar wires are placed from an intermediate ring not only to provide greater support but to protect 

the subtalar joint during tibiotalar compression. 

156 





FIGURE 17. Compression is applied through the tibiotalar 

joint. 

between the calcaneus and distal tibia is sufficient. 

However, in patients with intact subtalar joints, 

compression should only be applied across the 

tibiotalar arthrodesis site. To accomplish this, a 

fixed Bdistal ring block^ is applied to isolate the 

talus from the calcaneus and protect the subtalar 

joint. Through either extended connectors from the 

foot frame or an additional intermediate ring, 1 or 

preferably 2 thin wires are placed in the talus and 

appropriately tensioned. Care must be taken to 

ensure that the pins are indeed in the talus and do 

not engage the malleoli (Figs. 16A, B). 

14. Compression may be applied after all components 

of the external fixator have been tightened, and all 

thin wires have been tensioned. If the Steinmann pin 

placed longitudinally for provisional fixation is 

directly perpendicular to the arthrodesis site, then 

it can be used as a Brail^ during compression. The 

provisional fixation is typically removed at the end 

of the case (Fig. 17). 

FIGURE 18. Intraoperative fluoroscopy after compression. 

Note the bending of the tensioned thin wires in the talus. 

15. Intraoperative fluoroscopy is used to confirm 

adequate bony apposition at the arthrodesis site 

and proper pin position (Fig. 18). 

16. If there is concern for inadequate compression or a 

tendency toward varus malalignment at the tibiotalar 

joint, consideration should be given to a fibular osteotomy, 

if it was not already cut or resected during the 

approach. We favor an oblique osteotomy, proximal 

lateral to distal medial through a 2- to 3-cm incision. 

17. The wires are appropriately cut and bent. Alternatively, 

the pins can be cut flush with the external fixator. 

However, if a wire needs to be tensioned later, leaving 

a carefully bent residual wire allows for this. 

18. Sutures are used to close any extension of the stab 

incisions created for pin placement. 

FIGURE 19. A and B, Example of Taylor Spatial Frame being 

used for revision ankle arthrodesis that required posterior 

translation of the talus in addition to tibiotalar compression. 



FIGURE 20. Patient weight-bearing with external fixator. 

A foot plate with tread has been applied to the foot frame. 

19. Sterile dressings are applied and wrapped relatively 

tightly over the pins to provide stability at the 

skin/wire interface to decrease the likelihood of pin 

tract infections. 

Traditional Step-by-Step External 

Fixation Method 

1. The proximal ring/ring block is usually attached first 

(Fig. 6). A reference (thin) wire can be placed perpendicular 

to the anatomical axis of the tibia. The 

proximal ring is attached to this reference wire. A 

second thin wire is placed at a different angle and 

attached to the proximal ring that is being held in an 

orthogonal position. Ideally, this second wire should 

be placed as close to 90 degrees from the first to create 

FIGURE 22. Radiograph demonstrating loose proximal 

pins suspicious for pin tract infection/osteomyelitis. 

the greatest stability. In placing 2 thin wires on the 

same ring, one should be above and the other below the 

ring. If the pins are placed on the same side of the ring, 

they will collide and displace. These thin wires are 

tensioned. A second ring can be placed and secured in a 

similar manner. The 2 rings are connected by sockets or 

short threaded rods. The spacing between these 2 rings 

is variable and should allow for adequate stability (ie, 

adequate space should be left to permit half pin 

placement between the rings. To ensure that the 2 rings 

are symmetrically oriented, it may be easier to first 

connect the 2 rings, slide them onto the lower leg, have 

FIGURE 21. A, Ankle arthrodesis site obscured by external fixator, making assessment of fusion difficult. B, CT scan to 

facilitate assessment of fusion site. 

158 





FIGURE 23. A, Poor pin care and unstable skin around pins led to pin tract infection. B, Same patient after 10 days of 

proper pin care, and dressings to stabilize the skin-pin interface oral antibiotics. 

the assistant hold the rings in an orthogonal position, 

and place thin wires in both rings to maintain proper 

ring position. Half pins may then be added to both 

proximal rings if desired. Half pins stiffen the construct 

but are not essential. In fact, traditional Ilizarov 

teaching does not include half pins. We typically add 

2 half pins from the most proximal ring attached to a 

clamp and at least 1 additional half pin from the lower 

ring. Spacing between the proximal ring block and the 

distal construct should allow for compression. 

2. The foot frame is attached to the foot in the manner 

described for the prebuilt frame above (Fig. 7B). 

FIGURE 24. Patient with persistent postoperative infection. 

External fixator was not removed and maintained 

tibiolar compression during multiple debriments and even 

soft-tissue transfer. 

3. An intermediate partial ring or connectors from the 

foot frame are incorporated to attach to 1 or 

preferably 2 talar wires. The talar wires are tensioned 

after the intermediate partial ring or connectors have 

been secured to the foot frame. Next, threaded rods 

are added to connect the proximal ring block and 

foot frame construct. It is not problematic if the 

threaded rods do not line up exactly congruently/ 

symmetrically with both portions of the external 

fixator. Various connectors can easily be added to 

the proximal ring or foot frame to allow for 

longitudinal threaded rods that can be used for 

compression across the tibiotalar joint. To facilitate 

simplicity, the external fixator can be assembled in a 

graduated manner but, as mentioned above, the 

proximal and distal components are symmetrically 

oriented by loosely placing longitudinal threaded 

rods through the proximal and distal external 

fixator components. 

4. Adjustable struts to provide software-directed dynamic 

multiplanar correction are available (Taylor Spatial 

Frame, Smith & Nephew Richards, Memphis, TN) if 

alignment changes are necessary postoperatively. 

Whereas traditional frame constructs allow only immediate 

and subsequent compression at the arthrodesis 

site, the Taylor Spatial Frame readily affords angular, 

rotational, and translational correction to fine tune the 

relative positions of the tibia and talus for fusion. The 

details of this technique are beyond the scope of this 

paper (Figs. 19A, B). 

| POSTOPERATIVE MANAGEMENT 

The surgical incision must be protected adequately until it 

is sealed. Pin care should be initiated within the first week 

after application of the external fixator, but without 



contaminating the surgical wound. Many techniques have 

been suggested for pin care. Our preferred technique is to 

perform a mechanical debridement of the pin/skin interface 

using a 4 8-inch sponge moistened with a 50:50 

mixture of sterile saline and hydrogen peroxide. The 

moistened sponge is used to Bshoeshine^ the pins at the 

pin/skin interface and to debride the crusting that 

routinely develops. Skin compromise can be kept to a 

minimum by maintaining mild pressure on the skin at 

the pin site. Problems arise if the pin/skin interface is 

unstable. This constant irritation leads to pin site problems. 

Foam pads, vial caps, and specialized wraps have 

been devised; we prefer to use surgical sponges wrapped 

around adjacent pins in a figure 8 pattern and stacked to 

the level of the respective ring/frame component to 

which the pin is fastened. Irrespective of method, it is 

important to maintain this skin stabilization at pin sites 

that are problematic. 

We generally delay weight-bearing until the wound 

is healed. Then, we apply a foot plate with a tread for the 

patient to advance weight-bearing as tolerated (Figs. 

20A, B). Frequenly, by 4 to 6 weeks after ankle 

arthrodesis, full weight-bearing is tolerated by the patient 

in the external fixator. We routinely compress an additional 

1 to 2 mm at 2 to 3 follow-up visits, particularly if 

there is a suggestion of incomplete bony apposition at the 

tibiotalar arthrodesis site. 

Removal of the external fixator is determined based 

on follow-up radiographs and the suggestion of bridging 

trabeculation in at least 2 planes at the arthrodesis site. If 

the arthrodesis site is obscured by the external fixator on 

follow-up radiographs, a limited CT scan in the coronal 

and sagittal planes aids in assessing fusion (Fig. 21) 

Approximately 50% of external fixators are removed in 

the clinic setting. We recommend that external fixators 

that use hydroxyapatite-coated half pins be removed in 

the operating room. We routinely recommend that 

patients wear a walking cast for 3 to 4 weeks immediately 

after external fixator removal and graduate to 

an ankle foot orthosis, with a rockerbottom shoe 

modification, to be worn an additional 2 to 3 months 

as the pin sites fully heal, and the patient adapts to the 

ankle fusion. 

| COMPLICATIONS 

Intraoperative 

Pin placement, particularly thin wire application 

cannot be haphazard. Safe zones have been established 

to avoid neurovascular injury. Pins should be placed 

with the skin in a relaxed, tensionless position. If 

excessive skin tension occurs, the pin should be replaced. 

Alternatively, a small relaxing incision can be 

made. We recommend cold water/saline irrigation or 

holding pins with moistened sponges during pin placement 

to decrease the risk of bone and/or skin necrosis 

that may lead to pin tract infections, pin loosening, 

and osteomyelitis. 

Short-Term Postoperative 

Poor pin care will invariably lead to pin tract infections 

and, potentially, osteomyelitis (Fig. 22). Pin sites should 

be cleaned regularly, and the skin needs to be stabilized 

around the pin sites (Figs. 23A, B). If a pin tract should 

become infected and fails to respond to proper pin care 

and antibiotic management, the involved pin will need 

to be removed and replaced with a different pin in a minor 

operative procedure. Wound dehiscence is relatively rare 

because the external fixator maintains excellent stability 

FIGURE 25. A, Failed ankle arthrodesis using internal fixation. B, Same patient after revision ankle arthrodesis using 

external fixation. C, Follow-up radiographs after external fixator removal, demonstrating successful fusion. 

160 





of the ankle arthrodesis site, but just like for any surgical 

procedure, infections occasionally occur. The advantage is 

that no implant is located at the arthrodesis site; instead, all 

wires are far removed from the arthrodesis site. Another 

advantage is that the infection can often be managed 

without removing the external fixator, thereby maintaining 

compression at the arthrodesis site (Fig. 24). 

Ankle arthrodesis, regardless of technique, may go on 

to delayed union, nonunion, and malunion. Generally, 

delayed union is effectively managed with further 

compression applied to the arthrodesis site in the office 

setting. The risk of malunion (equinus, varus, and 

excessive valgus), as for arthrodesis using internal 

fixation, is typically avoided by proper intraoperative 

positioning of the tibiotalar joint. The advantage of 

external fixation is that subtle adjustments are typically 

still possible postoperatively. 

After external fixator removal, the patient should be 

protected in a walking cast, boot, or brace until the tibial 

pin sites have healed. With the stiffness at the ankle 

arthrodesis site, immediate full weight-bearing after 

external fixator removal may lead to stress fracture 

through a tibial pin site. 

Intermediate/Long-Term Postoperative 

Adjacent joint arthritis invariably develops over time 

but is not consistently symptomatic. Simultaneous 

subtalar compression may accelerate the development 

of subtalar arthritis and should be avoided with the 

proper frame construct. 

| RESULTS 

Results for ankle arthrodesis using ring external fixation 

have not been widely published. Hawkins et al 5 reported 

an 80% (16 of 20) good results in cases of complex 

distal tibial pathology or failed ankle arthrodesis treated 

with an Ilizarov external fixator. The authors pointed 

out that the Ilizarov fixator represents a reasonable tool 

for limb salvage and an alternative to amputation in 

difficult cases of ankle pathology (Hawkins et al). Calif 

et al 6 noted solid fusion in 14 of 14 ankle arthrodeses 

FIGURE 26. A, Failed total ankle arthroplasty. B, Implant removed, demonstrating bony defect at ankle. C, Proximal 

corticotomy with external fixator applied. D, Patient weight-bearing during simultaneous ankle compression and proximal 

distraction osteogenesis. E, Lateral radiograph of ankle arthrodesis site after removal of failed total ankle implants. 

F, Lateral radiograph of proximal tibia/fibula, demonstrating distraction osteogenesis. 



performed with Ilizarov external fixation for ankle 

pathology associated with extensive periarticular bone 

loss and severe deformity. All joints were fused in 

anatomical alignment, and patients had greatly 

improved their functional status. Sakurakichi et al 7 

noted that complex ankle arthrodesis could be effectively 

be performed with simultaneous proximal tibial 

lengthening using the Ilizarov external fixator. Although 

the series included only 6 patients, all patients healed 

their arthrodesis sites and gained 2 to 3 mm with 

simultaneous lengthening. 

Probably the most compelling article is Katsenis 

et al’s 8,9 report of 21 revision ankle arthrodeses 

performed using the Ilizarov external fixator to manage 

nonunions/malunions about the ankle. Despite the 

patients having complex hindfoot pathology, all 21 

healed and with a plantigrade foot. At an average 

follow-up of 12 years, 18 of 21 had good to excellent 

results. The authors pointed out that external fixation 

requires considerable attention and reported 20 major 

complications intraoperatively and 7 postoperatively. 

We conducted a similar study at our institution (on 

a program for American Orthopaedic Foot and Ankle 

Society Summer Meeting, San Diego, CA, July 2006). 

We analyzed 22 consecutive revision ankle arthrodesis 

performed for nonunions using ring external fixation 

(Figs. 25AYC). All patients had at least 1 prior attempt 

at arthrodesis using internal fixation. The average 

number of surgeries before revision arthrodesis was 2 

(range, 1Y8). External fixation was maintained for an 

average of 15 weeks (range, 12Y44 weeks). Union (time 

to removal of external fixation) was suggested by 

evidence of bridging trabeculation at the arthrodesis 

site in 3 standard radiographic views of the ankle. In 

cases where union could not be adequately determined 

on radiographic views or the arthrodesis site was 

obscured by the external fixator, a limited CT scan 

was obtained to assess union. All 22 patients were 

available for follow-up at an average of 51 months 

(range, 15Y62 months). The average American Orthopaedic 

Foot and Ankle Society ankle-hindfoot score 

improved from 26 points (range, 0Y45 points) preoperatively 

to 64 points (range, 0Y87 points) at final follow-up. 

Tibiotalar fusion was achieved in 19 (86%) of 22 

patients. In the 3 patients with persistent nonunions, one 

had avascular necrosis of the talus and two had persistent 

osteomyelitis. Two of these patients underwent rerevision 

arthrodesis and one opted for amputation. Over the 

course of treatment with external fixation, 34 minor 

complications (pin tract infections [n = 24], broken pins 

[n = 3], and cellulitis [n = 7]) were managed effectively 

with local wound care, oral antibiotics, and/or pin 

removal in the clinic setting. Four major complications 

(deep infection [n = 2] and wound dehiscence [n = 2]) 

162 


were surgically addressed, while maintaining compression 

at the arthrodesis site by external fixation. Three 

patients had symptomatic malunions: varus (n = 2), 

excessive valgus (n = 1), and equinus (n = 1). Hindfoot 

motion was less than physiological in all patients 

(compared with the contralateral extremity), despite 

the external fixator being constructed to protect the 

subtalar joint from concomitant compression. 

Possible Concerns and Future 

of This Technique 

External fixation techniques are not practical for all 

patients or surgeons. However, it is our opinion that 

surgeons managing complex foot and ankle disorders 

should have external fixation in their armamentarium 

because there are situations when internal fixation 

techniques are limited or contraindicated. Specifically, 

revision arthrodesis and cases of septic arthritis/osteomyelitis 

frequently lend themselves poorly to internal 

fixation. With some focused training in learning 

centers and residency training programs, most surgeons 

can acquire skills to apply external fixation to ankle 

arthrodesis. The future of this technique depends on 

adequate teaching being made available and userfriendly 

external fixation systems being developed. A 

limiting factor remains that many surgeons without 

formal external fixation training are intimidated by the 

complexity of the traditional Ilizarov system (Figs. 

26AYF). Newer systems have been introduced that tend 

to be more forgiving, although they may forfeit some of 

the versatility of the seemingly endless combinations of 

external fixation constructs afforded by the original 

systems. Although these newer systems may appear 

simpler, surgeons must become familiar at least with the 

fundamentals of the original Ilizarov method to consistently 

and successfully use external fixation in 

treating their patients with complex foot and ankle 

disorders. We foresee that basic external fixation 

techniques will become part of most residency training 

programs, more courses will be offered through learning 

centers as interest in external fixation grows, and 

surgeons will become more facile with techniques of 

external fixation. With emphasis on minimally invasive 

approaches and the evolution of computer-assisted 

surgery, external fixation will continue its development 

as an integral part of precise surgical management of 

complex disorders of the foot and ankle. 

| REFERENCES 


1. Monroe MT, Beals TC, Manol A 2nd. Clinical outcome of 

arthrodesis of the ankle using rigid internal fixation with 

cancellous screws. Foot Ankle Int. 1999;20:227Y231. 

[526Y535]. 



2. Thomas R, Daniels TR, Parker K. Gait analysis and functional 

outcomes following ankle arthrodesis for isolated ankle 

arthritis. J Bone Joint Surg Am. 2006;88:526Y535. 

3. Knecht SI, Estin M, Callahan JJ, et al. The agility total 

ankle arthroplasty. Seven to sixteen-year follow-up. J Bone 

Joint Surg Am. 2004;86A:1161Y1171. 

4. Meehan R, McFarlin S, Bugbee W, et al. Fresh ankle 

osteochondral allograft transplantation for tibiotalar joint 

arthritis. Foot Ankle Int. 2005;26:793Y802. 

5. Hawkins BJ, Langermann RJ, Anger DM, et al. The 

Ilizarov technique in ankle fusion. Clin Orthop Relat Res. 

Jun 1994;217Y225. 

6. Calif E, Stein H, Lerner A. The Ilizarov external fixation 

frame in compression arthrodesis of large, weight bearing 

joints. Acta Orthop Belg. 2004;70:51Y56. 

7. Sakurakichi K, Tsuchiya H, Uehara K, et al. Ankle 

arthrodesis combined with tibial lengthening using the 

Ilizarov apparatus. J Orthop Sci. 2003;8:20Y25. 

8. Katsenis D, Bhave A, Paley D, et al. Treatment of malunion 

and nonunion at the site of an ankle fusion with 

Ilizarov apparatus. J Bone Joint Surg Am. 2005;87: 

186Y191. 

9. Paley D, Lamm BM, Katsenis D, et al. Treatment of malunion 

and nonunion at the site of an ankle fusion with the 

Ilizarov apparatus. Surgical technique. J Bone Joint Surg 

Am. 2006;88:S119Y134. [Review].

Ankle Arthrodesis Using Ring External Fixation - Orthofix.com

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