Managing Wound-Healing Complications After Total Ankle Replacement

Abstract

Incision breakdown of the operative incision resulting in a wound is commonly encountered as a complication following total ankle replacement surgery. Healing problems can progress from superficial wounds to full-thickness necrosis of the skin and deeper tissues jeopardizing the ultimate retention of the prosthetic components leading to compromised patient outcomes. Preoperative identification of patient risk factors associated with breakdown of the operative incision after total ankle replacement should improve outcome of the procedure. Screening of those patients with risk factors for wound breakdown is recommended prior to total ankle replacement. A multidisciplinary approach should ensure once wound breakdown is identified to expedite soft-tissue coverage and preserve function of the total ankle replacement as well as maintain options for revision in the future.

Introduction

Wound-healing complications after total ankle replacement (TAR) have been quoted as high as 16–28 % [1, 2]. A disturbing finding is that by the end of 1 year of developing a wound-healing complication, 25 % of patients with wound-healing complications may require TAR explantation, and many will be infected [2]. Clearly identifiable risk factors for developing a postoperative wound-healing problem include tobacco use, peripheral vascular disease, and cardiovascular diseases [2]. Overall, what can be gleaned is that delayed wound healing may be the single most common wound-healing issue after TAR. It should be kept in mind that the anterior ankle has a rich blood supply, but the intervening tissue planes between skin and joint capsule are scant—there is a lack of inherent “backup” richly vascularized muscle, fat, or fascia. A high shear stress area requires extremes of motion and is subject to hydrostatic dependency forces, combined with the above rendering the anterior-distal soft-tissue envelope one that requires additional time to heal and remodel. Although the entire incision may be at risk for poor healing (Fig. 13.1), the area near the tibialis anterior tendon has been found to be a consistent area of wound breakdown (Fig. 13.2) [2–4]. Clearly, the patients’ health inventory and surgeon experience/technique must be factors in the development of wound-healing problems after TAR. However, it also seems apparent that wound-healing complications may be related to prosthesis design, vis-à-vis time, soft-tissue techniques required for component implantation, and biomechanical function, and may push the surgeon and host to their tolerances [1, 3, 5].

Fig. 13.1

Example of delayed healing that requires close follow-up. Local care may be expected to assist with expectant healing over the course of several weeks

Fig. 13.2

The area near the tibialis anterior tendon appears to be at greatest risk for wound breakdown. Techniques to temporarily suture tendinous structures together and “parachute” them down to deeper structures may help relieve pressure in this area of the incision (Photo courtesy of Benjamin Overly, DPM)

Prevention of Wound-Healing Complications

Treatment of wound-healing complications after TAR begins with prevention. Preoperatively, all patients must be evaluated for the presence of arterial inflow via palpable pedal pulses. Previous injuries may result in loss of antegrade tibialis anterior artery flow, with retrograde filling via the posterior tibial artery, and less commonly the peroneal artery. The “eyeball test ,” where simply inspecting for deeply pigmented or atrophic scars, poor skin turgor, massive edema, and tissue paper skin are visual alerts to microvascular or venous disease, even if a Doppler arterial signal is present. In revision settings, prior to any secondary surgery, transcutaneous oxygen (TCO₂ ) may be helpful along previous scars, as long as edema or a poor quality chest lead does not invalidate the results. A formal preoperative vascular surgery evaluation should be prompted when a lack of arterial inflow with nonpalpable pedal pulses with poor Doppler arterial signals or TCO₂ data is poor. Computed tomography angiogram and formal angiogram with distal runoff are helpful in discovering focal stenosis amenable to stenting or extensive disease that may require vascular bypass surgery.

Intraoperatively, meticulous soft-tissue handing, respect for preserving the cutaneous perforating vessels, and maintenance of hemostasis are important. Inadvertent injuries to larger vessels should be repaired, rather than tying off the vessel. Closure should be performed in multiple layers, utilizing gauges of suture appropriate to the tissue thickness of each patient. If possible, the lead author will transpose anteriorly a large low-lying peroneus tertius muscle belly, if it is present (Fig. 13.3). To cover the prosthetic components completely, tendons may be temporarily tenodesed with rapidly absorbing fine sutures and then “parachuted” deep into the incision, thereby relieving pressure in the incision and creating a tissue barrier over the TAR components (Fig. 13.4). Loss of the integrity of individual tendon sheaths or retaining structures should be addressed by reconstruction with a “tissue-friendly” product such as PriMatrix (TEI Medical, Boston, MA) (Fig. 13.4). Skin closure may be performed with nonabsorbable suture or staples. The author uses 2-0 and 3-0 polypropylene vertical mattress sutures when the skin is of poor quality. An indwelling drain is always placed to limit hematoma and removed when ≥15-cm³/shift for two consecutive shifts.

Fig. 13.3

Magnetic resonance imaging (left image) of a low-lying peroneus tertius muscle belly (blue hashed circle) and surface marking of its’ position (red speckled rectangle designated as A). This muscle can be transposed or formally transferred by detaching the tendon distally, to assist with providing vascularized muscle locally within the central/lateral portion of a wound dehiscence (blue filled oval)

Fig. 13.4

Temporary imbrication (tenodesis) of tendons and parachuting them down onto deep tissues takes pressure of the incision (a). Reconstruction of the retaining structures of the ankle with an ingrowth substrate (PriMatrix^®, TEI Medical, Boston, MA) not only prevents bowstringing but also relieves incision tension and provides an ingrowth medium if wound dehiscence were to occur, making negative-pressure wound therapy more effective (b)

Postoperatively, elevation is begun immediately after a well-padded splint is applied (the author uses triple padding/compression), and ice used to reduce edema and anticoagulation performed with aspirin 325 mg by mouth twice daily or low-dose unfractionated or fractionated heparin are the standard of care for in-house hospital patients for deep venous thrombosis prophylaxis, but may also have a favorable affect on arteriolar rheodynamics . In the past, a trend of placing patients on high-concentration supplemental oxygen via face mask has not proven to impact wound-healing problems. The author retains sutures or staples for 4–8 weeks, depending upon extremity edema and overall quality of the overlying soft-tissue envelope. Incisional negative-pressure wound therapy dressing between 50 and 100 mmHg for 3–5 days may assist in “tight” closures or the edematous limb (Fig. 13.5).

Fig. 13.5

Example of incisional negative-pressure wound therapy dressings (arrow and outlines) for tight or tenuous incision closure. The authors use spare foam to pad the skin from the suction hose (). Pressures are set at 50–100 mmHg continuous or intermittent for delicate skin

Treatments Based on Severity of Wound-Healing Problem after Total Ankle Replacement

Local Wound Care

Wound dehiscence that is superficial and does not span the length of the incision is commonplace after lower extremity surgery. These may be avoided by allowing more time for healing prior to suture removal. Delayed wound healing/dehiscence that is superficial may be treated expectantly with saline dressings, and “spitting” sutures should be removed. Skin sutures or staples remain in for all patients for 4 weeks, longer if the skin is of poor quality. We have found the combination of silver dressings, covered with an absorptive layer such as Polymen^® (Ferris Manufacturing Corp, Fort Worth, TX) and a “tissue-friendly adherent ” such as Mepitel^® (Monlycke Health Care, Gothenburg, Sweden) (Fig. 13.6) can reduce wound dressing needs to once per week. When infection is present, empiric systemic antibiotics may be commenced, and material for culture should be sought. Although a less common pathogen, unyielding low-grade wound problems with a clinically infected appearance that fail antibiotics ultimately yield Candida species yeast; thus, fungal cultures should be included in every culture sent from the beginning of the work-up. Negative-pressure wound therapy dressings with/without instillation therapy are an excellent modality for superficial wounds, with expectant healing within a few weeks. Thick split-thickness skin grafts (14–18/1000-in.) may be placed on the granulating bed (Fig. 13.7). Full-thickness skin grafts provide a thicker coverage with less secondary contraction. However, the author has found a lower rate of take for full-thickness skin grafts in the ankle region. Due to skin excursion and tension placed on the skin by the tendons under the skin, without an excellent granulation bed, the anterior ankle may develop into a hostile area for skin grafts, resulting in an unstable soft-tissue envelope that will require flap coverage (Figs. 13.8, 13.9, and 13.10).

Fig. 13.6

The combination of silver-coated dressings (a), PolyMem (b), and Mepitel (c) will assist in providing a dressing that is bactericidal and absorbs excessive surface fluid while allowing local fluid evaporation with a “tissue-friendly” self-adhesive

Fig. 13.7

Example of w ound with exposed tendon after total ankle replacement that was successfully managed by close follow-ups, serial debridements, and negative-pressure wound therapy dressings. A split-thickness skin graft is now ready to be applied (Photo courtesy of Benjamin Overly, DPM)

Fig. 13.8

Subacute wound dehiscence/necrosis with exposed tendons (a). Appropriate debridement to viable tissue may be followed by negative-pressure dressings prior t o final free flap coverage (b) (Photo courtesy of David A. Ehrlich, MD)

Fig. 13.9

Large surface area wound with tendons below a weak granulation bed. Although split-thickness skin grafting may be performed, this type of wound often results in a chronically unstable soft-tissue envelope, requiring resurfacing with a free flap in order to prevent future breakdown or allow future surgical approaches to manage total ankle replacement revision (Photo courtesy of Benjamin Overly, DPM)

Fig. 13.10

Chronic non-healing wound after total ankle replacement. Desiccated, exposed tendon surrounded by marginally viable tissue places this wound in consideration for free flap coverage. Due to extension of dysvascular soft tissue over the medial malleolar region and proximally, flap coverage will need to extend beyond the confines of the visible wound (dashed teardrop) (Photo courtesy of Benjamin Overly, DPM)

Operative Wound Debridement and Revision of the Incision

A full-thickness disruption of the incision, especially when full length, requires operative exploration. Cultures should be taken and infections managed as described elsewhere in this textbook. All devitalized tissue needs to be sharply excised, back to fresh bleeding tissue (Fig. 13.8). Tendons are loosely imbricated to “seal off” the underlying TAR. The peroneus tertius often has a low-lying muscle belly that may be formally transposed into the wound, introducing vascularized soft tissue into the problem area (Fig. 13.3). Reclosure may be attempted that may require “back cuts” or relaxing incisions, which is not as successful as one would hope. A layered closure is performed, with tension relief over the central area of the wound. Skin eversion and skin line relief is best accomplished with 2-0 polypropylene simple or vertical mattress sutures. An incisional negative-pressure wound therapy dressing may be used as a supplement, set at 50 or 100 mmHg, either in a continuous or an intermittent mode if tissue is friable (Fig. 13.5). Postope rative edema control is implem ented. Ankle range of motion is limited for 2–4 weeks until the revised wound “stabilizes.”

Debridement and Negative-Pressure Wound Therapy Dressings

Often, the bane of the surgeon is the area just lateral to the tibialis anterior tendon (Fig. 13.2). Judicious wound debridement, with an effort to save all vascularized tissue, is performed, followed by negative-pressure wound therapy dressing. It has been the authors’ experience that the KCI VAC^® (KCI, Vacuum Assisted Closure, San Antonio, TX) provides the most reliable system to achiev e negative-pressure wound therapy dressing treatment. When tendons are exposed, in order to pr event tendon desiccation, polyvinyl acetate foam (“white foam”) should be used. Another technique to prevent tissue desiccation is instillation therapy utilized with normal sterile saline or Prontosan (R. Braun Medical, Bethlehem, PA). Infected wounds must be debrided of necrotic tissues. Negative-pressure wound therapy with installation may be initiated with a number of agents (Table 13.1). The granulation potential must be assessed carefully: vascularity of the area being treated must be one that can provide rapid granulation ingrowth; otherwise early flap coverage must be considered. If granulation of the wound is rapid (within 1–2 weeks), tissue ingrowth substrates such as Integra Bilayer^® (Integra Life Science, Plainsboro, NJ) or PriMatrix may be placed over the defect and negative-pressure wound therapy continued. It cannot be stressed enough that wound inspection must be performed at a minimum of once or twice per week; any lack of progress in healing must be declared with a low threshold. At any time, when the author is utilizing negative-pressure wound therapy dressing and is entertaining the next level of care, soft-tissue flaps, hyperbaric oxygen therapy is incorporated into the management plan when feasible.

Table 13.1 Antibacterial solutions used by the authors that are effective agents with negative-pressure installation wound therapy

Local Soft-Tissue Flaps

The longitudinal anterior approach to the TAR posed some technical problems for flap coverage. Adjacent soft-tissue advancement flaps can help close small defects, with the donor region backfilled with a skin graft. Available regional flaps include the reversed sural flap, the lateral supramalleolar flap, and, for the very distal extent of the incision, an islandized pedicle plantar medial artery flap (Fig. 13.11). The extensor digitorum brevis muscle flap may be useful for small mid- to distal junction area of wound breakdown, but the size of the muscle belly is highly variable and adequate rotation may require sacrifice of the dorsalis pedis artery, making its use limited. Other muscle rotation flaps, such as the soleus and reverse peroneus brevis muscle flap (Fig. 13.12), have variable distal muscular perforator patterns and may be considered in proximal wound coverage, but may not always be reliable for anterior TAR wounds, especially the soleus. Tenodesis of the peroneus brevis tendon to the peroneus longus tendon must be preformed to preserve the importa nt eversion function of the peroneus brevis tendon insertion. The use of perforator-based posterior leg propeller flaps may be useful to cover TAR surgical wounds that have laterally based soft-tissue loss, with the advantage of less donor site morbidity than other local flaps (Fig. 13.13). Donor site morbidity with these flaps is a concern, but pre-lamination of the donor site PriMatrix in conjunction with flap delay techniques can help mitigate both flap complications and cosmetic issues at the donor site. These local flaps may be of great help in patients who otherwise are not medically fit to undergo a free flap procedure or when microsurgical services are not available. Large area wounds, especially with an exposed TAR, require free tissue transfer techniques.

Fig. 13.11

The reverse sural flap may cover large areas of the total ankle replacement incision (a). The plantar medial artery flap has limited reach to the distal anterior/medial ankle (b). The distally based lateral supramalleolar flap can transpose large area of tissue anteriorly but may expose anterior and lateral leg structures and has the worst potential flap donor site morbidity (c, d), and previous trauma or surgery to the sinus tarsi/subtalar joint area may render the distal pedicle (arrow) incompetent

Fig. 13.12

The reversed peroneus brevis muscle flap may provide limited proximal anterior wound fill. The soleus muscle flap, either as a standard flap or a distally based hemi-soleus variation, may not prove reliable coverage for distal one-third anterior tibia and ankle region coverage

Fig. 13.13

Sural artery skin perforator-based propeller flap (perforator, yellow arrow) for anterior total ankle replacement wound complication (white arrow, a). Propeller flap rotated (white dashed arrow), inset, and small residual donor defect backfilled with a split-thickness skin graft (b)

Free Tissue Transfers

Free flaps are the next step when local tissues are not available or suitable to cover the complex TAR wound. Free flaps may be described by their composite of tissue(s). In the past free muscle flaps were the workhorse for lower extremity coverage, such as the latissimus dorsi (Fig. 13.14), serratus anterior, rectus abdominis (Fig. 13.15), or the gracilis muscles (Fig. 13.16). Split-thickness skin grafting is performed on these pure muscle flaps. On occasion, in thin patients, these muscles may be harvested with a skin paddle (musculocutaneous free flaps), but bulk may require a secondary thinning procedure and placement of a final skin graft.

Fig. 13.14

Latissimus dorsi muscle free flap is quite large and has its greatest utility in massive wound coverage. This flap can be split based on its two main intramuscular coursing vessels to decrease bulk. It may also be taken with a small skin paddle and trimmed to fit smaller defects. A pedicled skin perforator flap based on the thoracodorsal artery (“TDAP” flap) may also be elevated, but a short pedicle length can limit its use in ankle coverage

Fig. 13.15

Appearance of a free rectus muscle flap with poor skin graft take. Bulk and a lack of subcutaneous padding are the relative disadvantages of free muscle flaps, unless a skin paddle is harvested. Nonetheless, free muscle flaps are still considered to be traditional reliable workhorse free flaps for myriad lower extremity reconstructions. The disadvantage of free muscle flaps is that elevation of the flap for secondary surgeries must be performed along the course of the pedicle (Photo courtesy of Benjamin Overly, DPM)

Fig. 13.16

Example of a gracilis muscle free flap for ankle coverage with lateral extension of the wound. Immediate split-thickness skin grafting is shown in right panel. Although significant flap atrophy will occur over the ensuing 6 months, shoe fit can be still difficult and de-bulking of the muscle may then be required

The use of free skin perforator flaps, such as the anterolateral thigh flap (ALT), the scapular and parascapular flaps, the radial and ulnar artery forearm flaps, and the thoracodorsal artery perforator flap, have revolutionized soft-tissue free flap surgery. A composite of flap containing skin/subcutaneous fat/fascia ± muscle, perforator skin flaps such as the ALT free flap have been demonstrated to provide equal coverage of traditional muscle flaps, but offer the advantage of offering a very supple, easily contoured flap that provides all the elements of the integument desired to cover lower extremity soft-tissue defects [6]. From a technical standpoint, to cover the anterior ankle, the ALT free flap possesses a vascular pedicle length and caliber that is well suited to the anterior tibial vessels, and the donor site can easily be closed primarily (Fig. 13.17a). Postoperative monitoring of the flap is facilitated by simple Doppler evaluation of the skin perforators. The ALT free flap has also found great utility in resurfacing anterior knee wounds prior to re-implanting total knee prosthesis. The same concept holds for the TAR; the ALT fasciocutaneous free flap provides full defect coverage with all desired tissue layers (skin/fat/fascia), and upon final flap “take” can be elevated easily or even incised through to gain access to the anterior ankle. The ALT free flap can even be placed to resurface an unstable anterior ankle soft-tissue envelope before the index primary TAR procedures. Although often a tedious dissection, for these reasons the ALT free flap has become our “go to” free flap to cover large anterior ankle defects or provide resurfacing prior to or after TAR (Figs. 13.16, 13.17, and 13.18). When soft-tissue coverage is needed along with a large amount of vascularized bone, the free osteocutaneous fibula flap (Fig. 13.19) can be quite useful. The free osteocutaneous deep circumflex iliac flap (Ruben’s osteocutaneous free flap , anterior iliac crest bone with skin free flap) and the parascapular osteocutaneous free flap can provide coverage accompanied with smaller amounts of vascularized bone.

Fig. 13.17

Free anterolateral thigh (ALT) flap (a). Note how thin and supple the ALT flap is; “x” marks the skin perforator; arrow marks the vascular pedicle. Example of free ALT flap used for soft-tissue coverage after an anterior ankle incision developed extensive distal central and medial wound necrosis . The advantage of skin perforator flaps is that once the flap is mature, future incisions may be placed anywhere within the flap. Clinical example of an acute wound breakdown that is negative for deep periprosthetic infection, with retention of total ankle replacement prosthetic components. Free ALT flap (left panel) has been placed to fill and resurface wound (right panel) (a). Clinical example of an infected total ankle replacement with a major wound complication. The total ankle replacement has been explanted, an antibiotic-loaded polymethylmethacrylate cement spacer placed and free ALT flap used for wound coverage in anticipation of possible late total ankle replacement re-implantation (b). Another clinical example of a catastrophic anterior ankle wound treated with free ALT flap coverage and external fixation to stabilize the ankle during soft-tissue healing (c)

Fig. 13.18

The free anterolateral thigh flap may be used both for acute anterior incision breakdown after total ankle replacement and to resurface a large area of chronically unstable, hostile soft-tissue envelope after multiple prior surgeries

Fig. 13.19

Free fibula osteocutaneous flap for limb salvage after severe distal tibial bone loss and anterior/medial soft-tissue loss after an infected total ankle replacement with massive wound complications. Intraoperative photograph of the harvested fibula osteocutaneous flap (a). Intraoperative image intensification view of free osteocutaneous flap in place (b). Lateral (c) and anterior (d) clinical photographs at 6 months postoperatively with external fixation system in place

Conclusions

Incision breakdown of the operative incision following total ankle replacement surgery is commonly encountered as a complication. Healing problems can progress from superficial wounds to full-thickness necrosis of the skin and deeper tissues jeopardizing the ultimate retention of the prosthetic components leading to compromised patient outcomes. A multidisciplinary approach should ensure once wound breakdown is identified to expedite soft-tissue coverage and preserve function of the total ankle replacement as well as maintain options for revision in the future.