Subtalar arthrodesis is a surgical procedure designed to treat chronic pain and instability in the subtalar joint, which is located in the hindfoot between the talus and calcaneus bones. This joint is essential for walking on uneven surfaces, as it helps with side-to-side foot motion. When damaged due to conditions like arthritis, trauma, or deformities, it can lead to significant pain and mobility challenges. This procedure involves fusing the subtalar joint, eliminating painful motion while stabilizing the foot. Subtalar arthrodesis is highly effective for individuals who have not responded to conservative treatments like orthotics, physical therapy, or medications.
How Common It Is and Who Gets It? (Epidemiology)
Subtalar arthrodesis may be necessary for individuals who experience chronic pain due to post-traumatic arthritis, primary osteoarthritis, congenital deformities, inflammatory joint diseases, or posterior tibial tendon dysfunction (PTTD). It is commonly recommended for patients who have experienced trauma to the foot or those with long-standing degenerative conditions affecting the subtalar joint.
Why It Happens – Causes (Etiology and Pathophysiology)
Subtalar arthrodesis is typically performed for conditions such as:
- Post-traumatic arthritis from injuries like calcaneal fractures
- Primary subtalar arthritis caused by wear and tear on the joint
- Tarsal coalitions or flatfoot deformities
- Inflammatory joint diseases like rheumatoid arthritis
- Posterior tibial tendon dysfunction (PTTD) causing instability in the foot
How the Body Part Normally Works? (Relevant Anatomy)
The subtalar joint is located just below the ankle joint, allowing critical movements such as inversion and eversion (side-to-side motion of the foot). These movements are essential for walking and running on uneven surfaces. The talus and calcaneus bones make up the joint, with cartilage that provides smooth motion. When this cartilage deteriorates, it can lead to pain and loss of function.
What You Might Feel – Symptoms (Clinical Presentation)
Chronic pain in the foot, difficulty walking, and reduced mobility are the hallmark symptoms of subtalar joint issues. Patients may experience stiffness, swelling, and pain with weight-bearing activities. The foot may become unstable, particularly during walking or running on uneven terrain.
How Doctors Find the Problem? (Diagnosis and Imaging)
Diagnosis begins with a physical examination, followed by imaging studies like X-rays, CT scans, or MRIs to assess the severity of joint damage. These tests help evaluate bone alignment and determine the extent of the arthritis or deformity.
Classification
Subtalar joint issues are classified based on severity, from mild osteoarthritis to advanced degeneration or post-traumatic arthritis. Conditions like tarsal coalition or flatfoot deformities may also be classified by the degree of foot misalignment.
Other Problems That Can Feel Similar (Differential Diagnosis)
Other conditions that may cause similar symptoms include Achilles tendinopathy, plantar fasciitis, and midfoot arthritis. Accurate diagnosis is essential to distinguish subtalar joint problems from these other conditions.
Treatment Options
Non-Surgical Care:
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- Activity modification
- NSAIDs for pain relief
- Custom orthotics or ankle-foot orthoses (AFOs)
- Steroid injections
- Physical therapy for strength and mobility
Surgical Care:
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- Subtalar arthrodesis (fusion) is the surgical option when conservative treatments fail to provide relief. The procedure involves fusing the bones of the subtalar joint to eliminate motion and reduce pain.
Recovery and What to Expect After Treatment
Post-surgical recovery requires patience. Patients typically wear a cast or boot for up to 12 weeks and avoid weight-bearing for 6–8 weeks. After this period, weight-bearing activities are gradually reintroduced, and physical therapy is started once the joint has fused. Full recovery can take 6–12 months.
Possible Risks or Side Effects (Complications)
- Nonunion: Failure of the bones to fuse properly, requiring additional surgery
- Infection: Though rare, infections can occur and may require treatment
- Hardware Issues: Loose or irritating screws that may need removal
- Reduced Range of Motion: Loss of motion in the fused joint, but other foot parts may compensate
Long-Term Outlook (Prognosis)
The majority of patients experience significant pain relief and increased foot stability after subtalar arthrodesis. However, the fused joint will lose motion, particularly in inversion and eversion. Most patients can return to normal daily activities, but high-impact sports may be limited.
Out-of-Pocket Cost
Medicare
CPT Code 28725 – Subtalar Fusion (Fusion of the Subtalar Joint): $182.74
Medicare Part B generally covers 80% of the approved cost for this procedure once your annual deductible has been met, leaving you responsible for the remaining 20%. Supplemental Insurance plans such as Medigap, AARP, or Blue Cross Blue Shield usually cover the remaining 20%, significantly reducing or eliminating out-of-pocket expenses for Medicare-approved surgeries. These plans work alongside Medicare to fill the coverage gap and reduce your financial responsibility.
If you have Secondary Insurance such as TRICARE, an Employer-Based Plan, or Veterans Health Administration coverage, it acts as a secondary payer. These plans typically cover any remaining coinsurance or small deductibles, which usually range from $100 to $300, depending on your plan and provider network.
Workers’ Compensation
If your subtalar fusion is required due to a work-related injury, Workers’ Compensation will cover all associated medical expenses, including surgery, postoperative care, and rehabilitation. You will not have any out-of-pocket costs, as the employer’s insurance carrier pays directly for all approved treatments.
No-Fault Insurance
If your subtalar joint fusion is needed due to an automobile accident, No-Fault Insurance will typically cover the entire cost of your treatment, including surgery and follow-up care. The only potential out-of-pocket cost may be a small deductible or co-payment depending on your insurance policy.
Example
Samantha Edwards required a subtalar fusion (CPT 28725) to treat severe arthritis in her foot. Her estimated Medicare out-of-pocket cost was $182.74. Since Samantha had supplemental coverage through Blue Cross Blue Shield, her remaining balance was fully covered, leaving her with no out-of-pocket expenses for the surgery.
Frequently Asked Questions (FAQ)
Q. What is Subtalar Arthrodesis?
A. Subtalar arthrodesis is a surgery where the subtalar joint is fused to eliminate pain caused by arthritis, injury, or deformity.
Q. When is Subtalar Arthrodesis recommended?
A. It is recommended when conservative treatments fail, and the patient suffers from chronic pain or instability in the subtalar joint.
Q. How is Subtalar Arthrodesis performed?
A. The surgery involves making an incision, removing damaged cartilage, and fusing the talus and calcaneus bones with screws or bone grafts.
Q. What is the recovery time?
A. Recovery typically requires 6–12 months, with 6–8 weeks of non-weight-bearing and gradual return to activity.
Q. What are the risks?
A. Risks include nonunion, infection, hardware issues, and reduced range of motion in the fused joint.
Summary and Takeaway
Subtalar arthrodesis is an effective treatment for individuals suffering from chronic pain and instability in the subtalar joint. By fusing the talus and calcaneus bones, the procedure eliminates painful motion and improves foot stability. While recovery can take several months, most patients experience significant pain relief and functional improvement. The procedure is especially beneficial for those who have not found relief with conservative treatments like physical therapy and orthotics. If you’re experiencing persistent pain or instability, subtalar arthrodesis may be a valuable option to improve your quality of life.
Clinical Insight & Recent Findings
A recent study published in Foot & Ankle International examined how GLP-1 receptor agonists—medications commonly used for diabetes and weight loss—affect healing after foot and ankle fusion surgeries.
Using data from over 1,500 diabetic patients who underwent tibiotalar, subtalar, or triple arthrodesis, researchers found that those taking GLP-1 medications (like semaglutide or tirzepatide) had significantly lower rates of pseudarthrosis (failed fusion), particularly after subtalar and triple arthrodesis procedures, without an increased risk of postoperative infection.
The findings suggest that GLP-1 agonists may enhance bone healing and fusion success in diabetic patients, possibly due to improved glucose control and positive effects on bone metabolism. Further clinical studies are encouraged to confirm these benefits. (“Study on GLP-1 medications and bone fusion success – see PubMed.”)
Who Performs This Treatment? (Specialists and Team Involved)
Orthopedic surgeons specializing in foot and ankle surgery typically perform subtalar arthrodesis. In some cases, a multidisciplinary team, including physical therapists and pain management specialists, may be involved in the preoperative and postoperative care.
When to See a Specialist?
If you have persistent pain in the foot or ankle that does not improve with conservative treatments, it’s important to consult a specialist. They can evaluate the severity of the condition and determine if surgical intervention is necessary.
When to Go to the Emergency Room?
You should seek emergency care if you experience severe pain, swelling, or an inability to move the foot following an injury, as this could indicate a fracture or dislocation.
What Recovery Really Looks Like?
Initially, you will need to keep weight off the foot for several weeks. Gradual movement and physical therapy will be necessary to regain function. Full recovery, including returning to normal activities, may take up to 6 months.
What Happens If You Ignore It?
Ignoring subtalar joint problems can lead to worsening pain, reduced mobility, and further joint damage. Without treatment, these conditions can significantly impact quality of life.
How to Prevent It?
While some causes of subtalar joint degeneration are unavoidable, using proper footwear, managing conditions like arthritis early, and avoiding excessive stress on the joints can help prevent the need for surgery.
Nutrition and Bone or Joint Health
Maintaining bone health is crucial for recovery. A diet rich in calcium and vitamin D, along with maintaining a healthy weight, can support joint function and promote healing after surgery.
Activity and Lifestyle Modifications
After surgery, you may need to modify certain activities to accommodate the loss of motion in the subtalar joint. Low-impact activities like swimming or cycling may be recommended to maintain fitness without stressing the joint.
Dr. Mo Athar
