Total Ankle Arthroplasty: Complications and Results

Intraoperative complications

Acute perioperative complications

Late postoperative complications

Malleolar fracture (medial or lateral)

Prosthetic dislocation

Loosening and subsidence of talar or tibial component

Distal tibial shaft fracture

Wound dehiscence

Pain

Tibialis posterior nerve compression

Joint stiffness (arthrofibrosis)

Neuroma of deep peroneal nerve

Chronic infection

Malleolar nonunion

Acute infection

Occasionally, isolated cases of vascular lesions have been reported, such as iatrogenic arteriovenous fistulas or pseudoaneurysms of the posterior tibial artery [2]. Although they are not frequent complications in prosthetic ankle replacement, their probability is increased in revisions due to the exhaustive debridement and the alteration in the habitual anatomy.

Glazebrook et al. have proposed a classification that categorically divides complications of prosthetic ankle surgery into low, medium, and high grade [3]. Low-grade complications are very unlikely to lead to implant failure (0%), medium-grade complications lead to revision in 17%–45% of cases, and high-grade complications cause implant failure in 69%–81%. However, Gadd et al. later proposed a simplification of this classification. When they applied the Glazebrook classification to their series of ankle prostheses they observed that, except for intraoperative fractures and wound dehiscence, the remaining complications had an incidence of prosthetic failure greater than 50% [4]. Therefore, Gadd et al. proposed only two grades: low grade (intraoperative fractures and wound dehiscence) and high grade (the remaining complications).

Roukis and Simonson observed a complication rate of 25% (8 patients) in a series of 32 patients with the Agility or Agility LP ankle prosthesis in which a revision was performed [5]. Most (87.5%) were classified as low grade. The remaining complications (12.5%) were unclassifiable and were related to unsolved neuropathic symptoms. There were no complications considered high grade in this series. It is also worth noting in this series that 75% of the complications occurred in the initial phase of the learning curve whereas only 25% (minor healing problems) arose in the final phases of the learning curve. Roukis and Simmonson concluded that, when comparing these results with the complications of the Agility or Agility LP primary prosthesis, the revision of this specific ankle prosthesis system during the surgeon’s learning period can be carried out safely when performed by a foot and ankle specialist [5].

15.2.1 Low-Grade Complications

15.2.1.1 Intraoperative Bone Fractures

In general, this is a relatively common complication in prosthetic ankle surgery. In revision surgery, the likelihood of fracture of the malleoli is notable due to the decrease in bone stock, osteoporosis due to disuse, or simply due to removing prosthetic implants or placing the new prosthesis.

Malleolar fractures (Fig. 15.1) are more frequent than fractures of the tibial diaphysis. The postoperative evolution of cases in which there has been a fracture of the tibial malleolus or peroneus, as well as in the distal tibia, is similar to those patients who have not had intraoperative fractures [1].

../images/479782_1_En_15_Chapter/479782_1_En_15_Fig1_HTML.jpg — Fig. 15.1

Intraoperative fracture of the tibial malleolus during revision total ankle arthroplasty (RTAA) with INBONE II prosthesis. Reduction and bone fixation were performed with two percutaneous K wires. Two months after the intervention, bone healing of the fracture can be observed with the presence of bone callus

In a retrospective review, Cody et al. observed up to 16 periprosthetic fractures, of which 3.5% required revision of the prosthesis or removal of the components [6]. In addition, patients with a bone mineral density low in the tibia, measured in Hounsfield units (HUs) in the preoperative CT, was strongly associated with a risk of periprosthetic fractures. Therefore, they recommend that an internal prophylactic fixation of the tibial malleolus be performed in patients with less than 200 HU.

15.2.1.2 Problems with Surgical Wound Healing

An important risk factor is a poor previous condition of the soft parts in the anterior ankle area. We must assess previous scars and a history of wound dehiscence.

It is important to place an adequate compressive bandage after the intervention to avoid edema and excessive scarring, as recommended in detail by Hsu et al. in their article [7]. Roukis and Simonson recommend making a window over the anterior incision in the padding under the plaster, and then placing a Robert Jones compression bandage and a molded posterior splint [5]. In this way, contact pressure on the anterior incision is limited and the Robert Jones bandage helps to reduce edema during the postoperative period.

Even with this approach and with intra- and postoperative precautions to avoid soft tissue contusion, wound dehiscence might occur in the first 2–3 weeks.

In most cases, the problem is superficial and is resolved with local wound cleaning and oral antibiotics. Those cases with a torpid evolution and deeper involvement might require plastic surgery to create cover flaps.

15.2.2 High-Grade Complications

15.2.2.1 Acute or Chronic Deep Infection

Myerson et al. did not find any deep prosthetic infection after the revision of the ankle prosthesis in their series [8]. This result is unlike the 3.2% rate of deep infections observed after implanting the Agility and Agility LP primary prosthesis or the 0.7% rate of profound infections diagnosed after implanting the Salto Talaris primary prosthesis.

In any case, Roukis and Simonson present great concern in this regard, and they recommend increasing efforts to minimize infection using the following protocol [5]:

Minimize the traffic and the number of people in the operating room to the minimum.
One week prior to surgery, the patient should perform a 5-min wash of the lower limb daily with 4% chlorhexidine gluconate.
Validated surgical preparation:
- Perform 3-min foot, ankle, and leg wash with sponges impregnated with chlorhexidine gluconate 4%.
- Paint with topical alcohol solution and 1% iodine (1 gr iodine/100 ml ethyl alcohol).
- Cover the fingers with a waterproof barrier.
- Intermittently repaint exposed skin with 10% povidone iodine solution.
- Irrigate the surgical site with a pulsatile washing system impregnated with 50,000 IU of bacitracin solution.
- Ensure a laminar flow system in the operating room without ultraviolet lights.
- Ensure each member of the surgical team uses double surgical masks.

15.2.2.2 Prosthetic Dislocation

This complication is infrequent and requires surgical intervention for replacement or repositioning of poorly positioned prosthetic components. Alternatively, we can assess medial or lateral instability, which would require ligamentous rebalancing:

Reconstruction of the lateral ligament complex, performed in our case preferably with ipsilateral semitendinosus plasty.
In the case of an insufficiency of the deltoid ligament, we opt for a hemitendon reconstruction of the posterior tibial tendon through a hole in the tibial malleolus or a descent osteotomy of the tibial malleolus (Fig. 15.2).

../images/479782_1_En_15_Chapter/479782_1_En_15_Fig2_HTML.jpg — Fig. 15.2

Revision total ankle arthroplasty (RTAA) with medial instability. (a) A tibial malleolar descent osteotomy was performed to give stability to the prosthesis. (b) Note the descent of the tibial malleolus and the bone fixation performed with two 3.5-mm compression screws

In some cases it is also necessary to realign the ankle, perform osteotomies on both malleoli, and place a thicker component [1].

15.2.2.3 Loosening and Sinking of the Talar Component

The main concern in the prosthetic revision of the ankle is ensuring a good anchoring of the components on deficient bone stock. The flat components are able to accommodate the transmission of forces at the bone-implant interface although the contact area is often sparse. Filling the defects with cancellous bone and bone matrix can help improve bone growth on the prosthetic components (Fig. 15.3).