What Is Subtalar Fusion?

Subtalar fusion — medically termed subtalar arthrodesis — is a surgical procedure that permanently fuses the talocalcaneal joint (the joint between the talus and calcaneus, comprising the posterior, middle, and anterior facets of the subtalar joint complex). By eliminating motion at this joint, the procedure eliminates the pain generated by an arthritic or unstable subtalar joint while preserving function in the surrounding ankle and midfoot joints.

At Balance Foot & Ankle, subtalar fusion is performed by our fellowship-trained surgeons as an isolated procedure for subtalar arthritis or as a component of a more extensive flatfoot reconstruction in patients with advanced deformity that cannot be adequately addressed by soft tissue and bony alignment procedures alone.

Indications for Subtalar Fusion

Subtalar Arthritis

Post-traumatic arthritis following calcaneal fractures is the most common indication for isolated subtalar fusion. Calcaneal fractures that violate the articular surfaces of the subtalar joint heal with cartilage damage and joint surface irregularity that progresses to symptomatic arthritis over months to years. The pain — located lateral and posterior to the ankle, worsened by walking on uneven ground, and associated with stiffness — is often initially attributed to residual fracture pain and may take one to three years to fully declare itself. Primary arthritis of the subtalar joint from other causes — systemic inflammatory arthritis, avascular necrosis, or idiopathic joint degeneration — is less common but managed with the same procedure.

Stage 3 Adult-Acquired Flatfoot Deformity

Adult-acquired flatfoot deformity from posterior tibial tendon dysfunction (PTTD) is graded from Stage 1 through Stage 4. In Stage 3, the subtalar joint has become rigid — the hindfoot valgus deformity cannot be passively corrected because of fixed deformity within the subtalar joint. Flexible reconstruction with calcaneal osteotomy and tendon reconstruction, which is appropriate for Stage 2 deformity, cannot achieve adequate correction when the joint is rigid. Subtalar fusion corrects the hindfoot valgus by fusing the joint in a neutral position, eliminating both the deformity and the arthritic pain.

Tarsal Coalition Revision

Talocalcaneal coalition resection that fails to provide adequate pain relief — particularly in patients with arthritic changes within the subtalar joint before resection — may be revised with subtalar fusion. Fusion addresses both the residual coalition and the arthritic joint surface, eliminating pain that cannot be resolved by resection alone.

Surgical Technique

Subtalar fusion is performed under general or spinal anesthesia in an outpatient or short-stay surgical setting. The patient is positioned laterally (on the non-operative side) with the operative foot accessible from both the lateral and medial approaches.

Joint Preparation

The subtalar joint is accessed through a lateral approach in the sinus tarsi region. The articular cartilage is completely removed from the posterior facet — and the middle and anterior facets when applicable — using osteotomes, curettes, and motorized burrs. The goal is to create flat, congruent, bleeding bone surfaces on both the talar and calcaneal sides of the joint that will unite into solid bone. Microfracture (multiple small perforations creating bleeding points) and bone grafting enhance healing in cases with bone loss or compromised healing biology.

Positioning and Fixation

The subtalar joint is positioned in slight valgus (2 to 5 degrees of heel valgus) — the physiologically optimal position that distributes load well and does not stress the adjacent ankle joint. Transverse plane rotation is adjusted to produce a plantigrade foot in the patient standing position. Guide wires placed under fluoroscopic guidance confirm correct positioning before definitive fixation.

Two large cannulated screws — typically 7.3 to 8.0 millimeter partially threaded screws — are placed from the inferior calcaneus into the talus, compressing the prepared joint surfaces together. The double-screw configuration provides superior rotational stability compared to a single screw. Supplementary fixation with a subtalar plate or staple is added in cases with significant bone loss or revision procedures where primary screw fixation alone may be insufficient.

Recovery After Subtalar Fusion

Weeks 0 to 6

Non-weight bearing in a splint or cast is maintained for the first six weeks while bone healing is established. Elevation is important for the first two weeks to minimize swelling. Toe exercises, knee and hip strengthening, and upper extremity conditioning maintain overall fitness during this period.

Weeks 6 to 12

Radiographic confirmation of early fusion healing at six weeks allows initiation of progressive weight bearing in a walking boot. Weight bearing increases from 25 percent to full over four to six weeks. Physical therapy begins to restore calf flexibility, ankle dorsiflexion, and gait mechanics.

Months 3 to 6

Transition to regular supportive footwear with custom orthotics at three to four months. Return to low-impact activities. CT scan at four to six months confirms solid bony fusion across the subtalar joint. Return to occupational activities depends on the physical demands of the job — sedentary workers return at two to three months, heavy manual laborers at four to six months.

Outcomes and Expectations

Subtalar fusion reliably eliminates subtalar joint pain in 80 to 90 percent of patients. The fused joint does not move — subtalar motion (the inward and outward tilt of the heel) is eliminated. This loss of motion is compensated to a significant degree by adjacent midtarsal joints, particularly the talonavicular joint. Most patients regain functional walking and are able to navigate uneven terrain with only mild limitation compared to before surgery.

Adjacent joint arthritis — particularly in the ankle and talonavicular joints — is a long-term concern after subtalar fusion. Proper fusion positioning and orthotic use minimize stress concentration at adjacent joints. Long-term follow-up studies show acceptable rates of adjacent joint arthritis development over 10 to 20 years in most patients, particularly when the fusion is positioned correctly and maintained in a custom orthotic.

Related Articles

• Ankle Pain Conditions Guide
• Custom Orthotics in Michigan
• Plantar Fasciitis Treatment Guide
• Heel Pain Causes and Treatment
• Bunion Treatment Guide

Frequently Asked Questions

How long does subtalar fusion surgery take?

The procedure typically takes 60 to 90 minutes depending on the complexity of the deformity and whether additional procedures such as tendon transfers or bone grafting are performed simultaneously. It is performed under general or regional anesthesia as an outpatient or short-stay procedure.

Can I walk normally after subtalar fusion?

Most patients walk with a normal or near-normal gait pattern after full recovery. The subtalar joint contributes to side-to-side motion rather than up-and-down ankle motion, so walking on flat surfaces is minimally affected. Walking on uneven terrain like gravel or hills requires more adaptation since the foot cannot tilt inward or outward at the fused joint.

What is the success rate of subtalar fusion?

Published studies report successful bone fusion in 90 to 95 percent of patients, with significant pain relief in over 85 percent. Factors that improve success include adequate joint preparation, rigid fixation with screws, compliance with non-weight-bearing instructions, and avoiding smoking during the healing period.

How long is recovery after subtalar fusion?

Recovery follows a structured timeline: 6 weeks in a non-weight-bearing cast or boot, 6 weeks transitioning to a walking boot with progressive weight-bearing, and 3 to 6 months for full return to activity. Most patients return to desk work at 2 to 3 weeks and physical work at 3 to 4 months, depending on job demands.

Your Board-Certified Podiatrists

Dr. Tom Biernacki, DPM

Board-Certified · FACFAS

Dr. Carl Jay, DPM

Board-Certified Podiatrist

Dr. Daria Gutkin, DPM

Podiatrist

Dr. Tom Biernacki, DPM

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Dr. Tom Biernacki, DPM is a double board-certified podiatrist and foot & ankle surgeon at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has reached over one million views.