Complex Ankle, Subtalar, and Triple Fusions

Published on 10/03/2015 by admin

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CHAPTER 19 Complex Ankle, Subtalar, and Triple Fusions

Arthroscopy allows surgeons to perform foot and ankle procedures that would otherwise be contraindicated because of the risks of an open approach. Although early in their development and more time-consuming than their open counterparts, combined arthroscopic subtalar and ankle fusion and arthroscopic triple arthrodesis have increasing roles to play in treating complex conditions in patients who are not candidates for an open procedure.

Arthroscopic ankle arthrodesis can be extended to include cases with some bone deformity or extensive osteophyte formation if the surgeon is patient and experienced with simpler cases.1 These cases should be performed after the surgeon has achieved proficiency with arthroscopic ankle and subtalar fusion. When the soft tissue envelope is compromised, the additional time required for the more complex operation may be justified by the prevention of soft tissue complications.

NORMAL AND PATHOLOGIC ANATOMY

Anatomic considerations are addressed in Chapter 17. Talonavicular arthritis with deformity or subtalar arthritis is a clear indication for triple arthrodesis. Isolated talonavicular arthritis may be amenable to isolated talonavicular fusion. However, an isolated talonavicular fusion is more likely to progress to a nonunion because there may be motion across the joint despite two screws being used for fixation. Because no significant gain in motion is achieved with an isolated talonavicular fusion compared with a full triple arthrodesis, a triple arthrodesis may be preferable because a larger fusion mass is obtained and better stabilization performed.

Usually, these procedures are performed open. However, for patients with bleeding problems (e.g., hemophilia), poor wound healing, or preexisting scar, a less invasive procedure may be preferable. For patients with anticipated wound-healing problems who are not candidates for an open procedure, an arthroscopic fusion is an ideal alternative.

PATIENT EVALUATION

History and Physical Examination

Physical Examination

Both extremities should be exposed to the knee. While standing, alignment of the hindfoot and forefoot is assessed from behind and in front of the patient.

Gait is observed, concentrating on stance and swing phases. Pain is associated with a reduced stance phase on the painful side and failure to toe-off. On inspection, the location and size of scars, calluses, and ulcers are recorded.

Palpation is used to determine the area of maximum tenderness. In ankle arthritis, this is localized on the anterior and posterior joint margins between the malleoli. For the subtalar joint, the pain is under the fibula, toward the sinus tarsi, behind and inferior to the ankle, and under the medial malleolus. For the talonavicular joint, tenderness is localized medially behind and above the navicular tubercle and just anterior to the ankle joint.

Assessing range-of-motion deficits may assist in determining the painful joints. To isolate the ankle, the examiner should move the talus on the tibia and palpate the joint margin at the same time. For the subtalar joint, the calcaneus is moved on the talus, and for the talonavicular joint, the navicular is moved on the talus. Absolute motion is difficult to measure, but pain and loss of motion (i.e., normal, mild, moderate, or severe restriction) is more instructive than the actual degree of motion.

Special tests include a single-leg heel raise to determine the integrity of the tibialis posterior tendon and the foot’s ability to act as a lever arm. Pulses and sensation should be assessed and recorded.

TREATMENT

Complex Arthroscopic Ankle Fusion