CHAPTER SYNOPSIS:
The use of total ankle arthroplasty is seeing a resurgence, and with an increase in the number of these procedures being performed, there will inevitably be an increase in failures. The techniques, pitfalls, and potential complications of salvaging an ankle replacement with an arthrodesis are discussed in this chapter.
HISTORY/INTRODUCTION/SCOPE OF THE PROBLEM
Ankle arthroplasty has been an option for treating ankle arthritis for over 30 years. While early results were not very promising, new designs, good long-term results, and an aging population have been responsible for a resurgence in popularity of the ankle replacement. In 2006, 1400 ankle replacements were performed in the United States. As the number of total ankle arthroplasties (TAAs) increases each year, the foot and ankle specialist will be faced with a new problem of dealing with the failed ankle replacement. When an ankle replacement fails, the surgeon is left with a difficult challenge, and the choices are limited to revision, fusion, or amputation. This chapter will concentrate on strategies and techniques for treating a failed ankle replacement with ankle arthrodesis.
INDICATION/CONTRAINDICATIONS
Failure of a TAA often presents as pain and swelling. Patients may complain of start-up pain and walk with an antalgic gait. There may be a change in the hindfoot alignment, which can be seen on clinical examination. Weight-bearing radiographs should be inspected and compared with those from previous examinations. Often radiographs will demonstrate osteolysis, loosening, syndesmosis failure, or subsidence. If the radiographic findings are not conclusive, a bone scan can be useful for identifying a loose component. A computed tomography scan can also be invaluable to determine the extent of bone cysts, mode of failure, and involvement of the subtalar joint ( Fig. 23-1 ).
It is always important to rule out the presence of infection. If an infection is suspected, the erythrocyte sedimentation rate and C-reactive protein should be measured. Some authors advocate a labeled white blood cell indium-labeled bone scan. Aspirate of the ankle joint specifically looking for white blood cell count, Gram stain, and culture may be useful; however, a negative finding does not exclude infection. If one still suspects the presence of infection at the time of surgery, an analysis of tissue by a pathologist can be undertaken to look at the polymorphonuclear leukocytes per high-power field. Extrapolating data from the hip and knee arthroplasty literature, greater than 10 polymorphonuclear leukocytes per high-power field would represent an infection. If infection is identified, then a two-stage procedure is recommended with the first stage involving removal of the components and placement of an antibiotic spacer.
CLASSIFICATION OF MODES OF FAILURE OF TOTAL ANKLE REPLACEMENTS
See Box 23-1 .
Type 1: Simple failures with minimal bone loss, no soft tissue compromise, no compromise of the subtalar joint
Type 2: Minimal bone loss, no subtalar involvement, but significant soft tissue compromise precluding the use of an anterior approach to the ankle
Type 3a: Major bone loss on tibial side, normal soft tissue envelope
Type 3b: Major bone loss on tibial side as well as anterior soft tissue compromise.
Type 4: Any mode of failure with talar collapse or subsidence that include the subtalar joint
SURGICAL TECHNIQUE
There are several ankle replacement designs that are approved for use in the United States by the U.S. Food and Drug Administration. Worldwide, there are 21 ankle replacement types in use. The mode of failure is not that different with the different designs. Tibial component subsidence is more common than talar component subsidence, except for the first-generation Agility talus, which had a small triangular shape covering less than half of the talar cut surface.
The modes of failure are no different than those in hip and knee replacements.
Early Failures Are Due to
- 1
Inappropriate bone cuts—too much tibia, leaving the component in soft cancellous bone with minimal support to axial load
- 2
Components too small–—no cortical weight-bearing anterior and/or posterior where the strongest bone is located
- 3
Asymmetric load due to malalignment or ligamentous instability
- 4
Infection
- 5
Avascular necrosis of the talus secondary to preparation of the talar cuts
- 6
Syndesmosis nonunion—unique to the Agility ankle
Late Failure Causes
- 1
Particle wear with bone cysts and weakening of the bone structure
- 2
Asymmetric load due to component or ankle/leg misalignment
- 3
Ligamentous instability with increased load and wear
- 4
Syndesmosis nonunion—unique to the Agility ankle
Surgical Options
A failed total ankle replacement can be salvaged with a revision replacement or a conversion to a fusion.
Indications for a Revision Replacement:
- 1
Failure with minimal bone loss
- 2
Adequate bone stock, especially on the talar side
- 3
Adequate/normal ligamentous balance
- 4
Good revision options available to the surgeon. (Most revisions at this point require custom components.)
- 5
No medical contraindications
Indications for a Conversion of a Failed Total Ankle Arthroplasty to a Fusion
- 1
Substantial bone loss
- 2
Inadequate revision component options
- 3
Inexperience with revision replacements
- 4
Ligamentous insufficiency
- 5
Infection
Options for an Ankle Fusion after a Failed Total Ankle Replacement
Several issues come into play when considering a conversion of a failed TAA to a fusion. These include the soft tissue envelope, as well as the mode of failure (see Box 23-1 ; Table 23-1 ).
| Failure | Mode | Surgical Approach |
|---|---|---|
| Type 1 |
| Anterior. Peri-articular plate. Leave malleoli intact |
| Type 2 | Major soft tissue compromise. Minimal bone loss. No subtalar involvement. |
|
| Type 3a | Major tibial bone loss. Normal soft tissue envelope | Anterior periarticular/blade plate or transfibular lateral or posterolateral blade plate |
| Type 3b | Major tibial bone loss, as well as anterior soft tissue compromise. | Transfibular lateral or posterolateral approach with blade plate fixation |
| Type 4 | Any mode of failure that also includes the subtalar joint | Intramuscular rod fixation with removal of the components through an anterior approach, or blade plate through a transfibular approach |
Related posts:
Allograft Resurfacing of the Tibiotalar Joint
Recognition and Salvage of the Failed Ankle Replacement Arthroplasty
Infection Following Total Ankle Arthroplasty
Diagnosis and Classification of Bone Defects: The Effect on Total Ankle Arthroplasty
Tendon Transfers for Acquired Posterior Tibial Tendon Deficiency
Midfoot Arthritis: Nonoperative Treatment and Arthrodesis
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
