Indications: end-stage ankle arthritis

Contraindications: an active infection or a history of one, peripheral vascular disease, osteomyelitis, a current infection or a history of one, inadequate neuromuscular status, sepsis, skeletal immaturity, neuropathy, severe ankle instability or severe malalignment that cannot be corrected, insufficient bone stock, excessive loads due to patient weight or activity, pregnancy, uncooperative patient or neurologic disorders resulting in noncompliance, and osteonecrosis of the talus.

Physical examination

Radiographs:

The patient is supine on the operating room table with all extremities well padded.

A bump is placed underneath the ipsilateral hip to bring the foot into a neutral position or into slight internal rotation.

A nonsterile tourniquet should be placed on the operative thigh.

The lower extremity is prepped and draped in a normal sterile manner.

Exsanguinate the lower extremity using an Esmarch bandage and inflate the tourniquet.

The incision is made one fingerbreadth lateral to the tibial crest and extends distally to the level of the talonavicular joint (Figure 10-1).

Dissect through the subcutaneous tissue to identify the superficial peroneal nerve. Often, a medial branch of the nerve at the level of the tibiotalar joint may need to be sacrificed to sufficiently mobilize the nerve to protect it throughout the remainder of the case.

The extensor retinaculum is incised over the extensor hallucis longus tendon (Figure 10-2).

The deep neurovascular bundle is mobilized and retracted laterally, and the tibialis anterior is retracted medially. Make every attempt to preserve the tibialis anterior into its own sheath to prevent postoperative adhesions (Figure 10-3).

A midline capsulotomy is performed to protect the neurovascular bundle. Once distal to the tibiotalar joint, the capsulotomy may be angled slightly medially to avoid the deep bundle (Figure 10-4).

Excess soft tissue is removed from the anterior aspect of the distal tibia. Any loose osteophytes may be removed as indicated by the preoperative plan. Stable osteophytes must be preserved to ensure proper fit of the tibial cutting guide.

The alignment guide is placed against the anterior aspect of the distal tibia. The fit of the alignment guide with respect to the patient’s tibia may be compared to that of the preprinted distal tibial model to ensure that the guide is positioned correctly in the patient. The guide is pinned to the tibia (Figures 10-5 and 10-6).

Confirm correct positioning of the alignment guide with an anteroposterior (AP) fluoroscopic imagine (Figure 10-7).

Once the alignment is confirmed, two additional pins are placed through the alignment guide. All pins should be bicortical to ensure proper fixation.

The coronal sizing guide is placed over the pins and secured to the distal tibia (Figure 10-8).

The sizing guide is placed over the pins and secured to the tibia (Figure 10-9).

Intraoperative fluoroscopy is utilized to confirm appropriate sizing of the tibial cut, as well as correct position of the cut guide with respect to its medial/lateral position. Care must be taken not to oversize the component because of concern about violating the malleoli. The corners of the tibial cut should match the medial and lateral gutters. In addition, the implant should be centered with respect to the distal tibia.

Once the correct position is confirmed, the corners of the tibial cut are reamed (Figure 10-10).

Remove the coronal sizing guide and replace with the resection guide by sliding it over the two distal pins. Additional fixation can be achieved with a more central pin through the cutting guide, placed from medial to lateral to avoid the neurovascular bundle posterior to the medial malleolus.