Salvage of Failed Total Ankle Arthroplasty

While the patient is standing, perform a thorough clinical investigation of both lower extremities to assess

• Alignment

• Deformities

• Foot position

• Muscular atrophy

• Soft tissue condition (e.g., existing scars)

While the patient is sitting with free-hanging feet, perform an assessment of

• Extent to which a present deformity is correctable

• Preserved joint motion of the ankle and subtalar joints

• Ligament stability of the ankle and subtalar joints with anterior drawer and tilt tests

• Supination and eversion power (e.g., function of posterior tibial and peroneus brevis muscles)

Plain weight-bearing radiographs, including anteroposterior (AP) views of foot and ankle and lateral view of the foot, to determine/rule out

• Component position

• Lucency zone beneath component

• Extent of destruction of underlying bone stock (e.g., tibia, talus, fibula)

• Status of neighboring joints (e.g., associated degenerative disease)

• Deformities of the foot and ankle complex (e.g., heel alignment, foot arch, talonavicular alignment)

• Bony condition (e.g., avascular necrosis, bony defects, osteoporosis)

• Fig. 59.1 shows a 67-year-old male patient, 5.8 years after primary arthroplasty, evidencing cyst formation on AP ( Fig. 59.1A ) and lateral ( Fig. 59.1B ) plain radiographs.

  

Computed tomography scan may be obtained for assessment of

• Bone-implant interface

• Bony defects

• Cyst formation

• Avascular necrosis

• Fig. 59.2 shows coronal ( Fig. 59.2A ) and sagittal ( Fig. 59.2B ) views of the same patient as in Fig. 59.1 .

  

Single-photon emission computed tomography with superimposed bone scan may be used to visualize

• Bone-implant interface

• Stress reaction (e.g., medial malleolus, fibula)

• Bony impingement

• Morphologic pathologies and associated activity process

Usually, the scar from the previous incision is used.

The scarred extensor retinaculum is exposed through a 10–12-cm incision.

The retinaculum is dissected along the lateral border of the anterior tibial tendon, and the anterior aspect of the distal tibia is exposed.

While the soft tissue mantle is dissected with the periosteum from the bone, attention is paid to the neurovascular bundle that lies behind the long extensor hallucis tendon.

A capsulotomy and capsulectomy are made, and a self-retaining retractor is inserted to carefully keep the soft tissue mantle away.

The prosthesis is exposed and explored with regard to instability, dysfunction, loosening, bony impingement, and wear. The components are then removed.

• In most instances, the polyethylene insert is removed first.

• The tibial component is removed next, taking care not to damage the bone stock ( Fig. 59.5A ).

  

• The talar component is then removed, again taking care not to damage the bone stock ( Fig. 59.5B ).

The remaining bone surfaces are carefully débrided from any soft tissue formation and avascular bone. Fig. 59.5C shows the talar surface after débridement, and Fig. 59.5D shows excised cyst material from the same patient as in Fig. 59.1 .

The medial and lateral compartments are also débrided.

While the foot is held in a neutral position, the overall defect is measured.