Subtalar Arthrodesis



Subtalar Arthrodesis


Harold B. Kitaoka



Arthrodesis of the subtalar joint is an operation designed to address the pain and impairment associated with subtalar arthritis and/or instability (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12). Although joint replacement was attempted in the past, there are currently no effective arthroplasties for the subtalar joint. It may be accomplished arthroscopically, or open with medial or posterior approaches, but the standard technique is an arthrotomy through a lateral incision (1,2). The previous philosophy that the hindfoot joints function in concert and thus it is necessary to fuse all three joints with a triple arthrodesis is no longer standard. The patient’s sense of stiffness and the potential for adverse effects on adjacent joints such as the ankle are considerably less with the more limited subtalar arthrodesis. Routine use of supplemental iliac crest bone graft is not required, and internal fixation with a compression screw is effective (1,2).


INDICATIONS AND CONTRAINDICATIONS



Contraindications



  • Contraindications include patients who have multilevel disease, such as ankle and subtalar joint arthritis.


  • An unrecognized coexisting ankle disorder may be a source of patient dissatisfaction and persistent symptoms.


  • Arthritis of multiple hindfoot joints is common, such as posttraumatic arthritis of subtalar and calcaneocuboid joints after an intraarticular calcaneal fracture.


  • Widespread arthritis affecting the hindfoot and midfoot is unlikely to be successfully addressed with subtalar arthrodesis.


  • Other contraindications are local or general medical conditions, which may preclude a successful result such as dysvascular extremity, local or remote infection, or a patient who cannot comply with or tolerate the required postoperative management of cast immobilization and no weight bearing.



  • A relative contraindication is a significant sensory neuropathy or neuropathic arthropathy and neuropathic fractures.


  • Only rarely is arthrodesis indicated in severely deformed, unbraceable hindfoot with recurrent neuropathic ulceration.


  • Another relative contraindication is advanced age. Some experts think that tobacco use is a relative contraindication.


  • The limitations of the technique include more rigid, severe hindfoot deformities. Pathologic disorders involving the talonavicular and calcaneocuboid joint may require extension to a triple arthrodesis.


  • Patients who sustain severe trauma to the hindfoot resulting in late posttraumatic arthritis of the subtalar joint frequently have other problems not addressed by subtalar arthrodesis, such as a compartment syndrome and its sequelae, smashed heel pad syndrome, nerve injury, and trauma to the adjacent hindfoot or midfoot or ankle joints.


  • A severe bony deficiency, such as that after multiple debridement operations for septic arthritis of the subtalar joint, or a severely malunited and impacted calcaneal fracture may require supplemental bone graft.


  • Patients with symptomatic anterior ankle impingement due to severe malalignment from a calcaneal fracture may require subtalar distraction arthrodesis to restore the normal talar declination angle.


PREOPERATIVE PREPARATION



  • Patients with subtalar arthritis typically complain of “pain on the outside of the ankle.” Symptoms are mechanical in nature, increased with weight bearing, and relieved with rest.


  • Patients often complain of more difficulty ambulating on uneven terrain, such as the yard, gravel, or side of the road. There is often swelling about the hindfoot and ankle. Patients may notice an uneven wear pattern of the shoes, inability to fit into usual footwear, and improved symptoms with use of boots or high top shoes that limit hindfoot motion.


  • It is important to distinguish subtalar from ankle disorders. This may be accomplished by physical examination that reveals tenderness localized to the sinus tarsi, absence of tenderness in the joint line of the ankle, and absence of instability during ankle stress testing.


  • There is often painful and restricted hindfoot motion with or without crepitus and painless ankle movement. Passive motion of the hindfoot and deep palpation of the sinus tarsi may reproduce the patient’s characteristic symptoms.


  • It is important to distinguish subtalar from transverse tarsal joint disease (e.g., calcaneocuboid, talonavicular). Patients may have an antalgic gait and atrophy of the affected leg musculature. Hindfoot deformity may be quantitated clinically with a standing tibiocalcaneal angle and measured with a goniometer. Neurovascular examination must be documented along with the condition of the soft tissue envelop about the hindfoot.


  • Radiologic assessment includes standing anteroposterior, lateral, and oblique views of the foot and standing anteroposterior, lateral, and mortise views of the ankle. These may demonstrate findings typical for subtalar arthritis (e.g., osteophytes, joint space narrowing, subchondral cysts, subchondral sclerosis) and are useful for determining the presence of coexisting problems of the ankle, hindfoot, or midfoot. Weight-bearing views are also useful for assessing the alignment of the ankle and hindfoot. Special diagnostic studies, such as tomography of the hindfoot, computed tomography, magnetic resonance imaging, technetium bone scan, and stress views of the ankle or subtalar joint, are occasionally useful.

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Jun 14, 2016 | Posted by in ORTHOPEDIC | Comments Off on Subtalar Arthrodesis
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