Carpal tunnel syndrome in the foot causes symptoms and treatment

Ankle pain on the outer side may initially seem mild or feel like a simple strain after walking or exercising. However, over time, it can develop into a troublesome condition that affects daily movement and activities. One of the most important causes of this type of pain is Sinus Tarsi Syndrome, a condition that affects a small area within the ankle that plays a key role in stability and movement.The challenge is that its symptoms often resemble those of other conditions, such as ankle sprains or tendon inflammation, which can sometimes delay an accurate diagnosis. In this article by Dalili Medical, we will discuss the causes of Sinus Tarsi Syndrome, its most common symptoms, the potential complications that may arise if it is left untreated, and the most effective treatment options, including medications, physical therapy exercises, and surgery in severe cases.

What Is Sinus Tarsi Syndrome?

Sinus Tarsi Syndrome is a condition that causes pain on the outer side of the ankle. It results from inflammation or irritation of a small anatomical space called the sinus tarsi, located between the bones of the subtalar joint. This area plays an important role in maintaining foot stability and movement.

Is It a Serious Condition?

Sinus Tarsi Syndrome is generally not considered a serious condition. However, it can be uncomfortable and may affect a person's quality of life by causing:

Chronic ankle pain
Difficulty walking or performing daily activities
A feeling of ankle instability

How Can It Be Distinguished from an Ankle Sprain?

Ankle Sprain

Causes sudden, sharp pain following an injury
Symptoms usually improve gradually with rest and proper treatment

Sinus Tarsi Syndrome

Causes persistent or recurring pain
Often accompanied by a sensation of ankle instability
Pain typically worsens with walking, physical activity, or prolonged standing

Can It Occur Without a Previous Injury?

Yes. Sinus Tarsi Syndrome can develop even without a clear history of ankle sprain. Common contributing factors include:

Repetitive stress on the foot and ankle
Flat feet (pes planus)
Weakness of the ankle muscles and ligaments

Why Does the Pain Increase When Walking on Uneven Surfaces?

Pain tends to worsen on uneven ground because the ankle joint must work harder to maintain balance and stability. This increases stress on the inflamed sinus tarsi region, leading to greater discomfort.

Does Obesity Affect the Condition?

Yes. Excess body weight can negatively impact Sinus Tarsi Syndrome by:

Increasing the load and pressure on the ankle joint
Worsening pain symptoms
Slowing the recovery process

Is Heat or Ice Better?

The appropriate choice depends on the stage of the condition:

Ice Therapy

Recommended during the early stage or when active inflammation is present
Helps reduce pain and swelling

Heat Therapy

More suitable after the acute inflammation has improved
Helps reduce stiffness and improve joint flexibility

Types of Sinus Tarsi Syndrome

Sinus Tarsi Syndrome can be classified into several types based on its cause and pattern of development:

1. Acute Type

Occurs after a direct injury or severe ankle sprain
Causes sudden and noticeable pain
May be associated with rapid swelling
Commonly linked to sports injuries or falls

2. Chronic Type

Develops gradually over time
Usually results from recurrent ankle sprains or continuous stress
Causes persistent or intermittent pain
Often accompanied by a feeling of ankle instability

3. Instability-Related Type

Primarily caused by weakened ankle ligaments
Patients often feel that the foot is unstable while walking
Pain typically worsens on uneven surfaces

4. Inflammatory Type

Results from inflammation of the tissues within the sinus tarsi
May occur even without a previous injury
Pain increases with pressure on the area or with movement

Causes of Sinus Tarsi Syndrome

Sinus Tarsi Syndrome most commonly develops as a result of repetitive stress or recurrent injuries affecting the outer side of the ankle, particularly when there is reduced stability of the ankle joint.

Main Causes

1. Recurrent Ankle Sprains

The most common cause of Sinus Tarsi Syndrome.
Each sprain can increase inflammation within the sinus tarsi region.

2. Previous Ankle Injury

The condition may develop even after an earlier injury has healed.
Residual ligament weakness or chronic inflammation may persist and contribute to symptoms.

3. Ankle Joint Instability

Weak ankle ligaments can lead to excessive or abnormal movement during walking.
This increases friction and stress within the sinus tarsi.

4. Excessive Stress on the Foot

Activities such as running or prolonged standing can place repeated strain on the ankle.
The risk is higher when walking or exercising on uneven surfaces.

5. Foot Structural Abnormalities

Conditions such as flat feet (pes planus) or high arches can alter weight distribution across the ankle.
This may increase pressure on the sinus tarsi region.

6. Sports-Related Injuries

Sports that involve jumping, pivoting, or rapid changes in direction increase the risk.
Examples include football, basketball, and running.

7. Chronic Inflammation of Joint Tissues

Inflammation of the synovial membrane or surrounding tissues within the joint may cause persistent pain.
Chronic inflammation can contribute to long-term symptoms.

Symptoms of Sinus Tarsi Syndrome

Symptoms typically occur on the outer side of the ankle and often worsen with movement or pressure on the foot.

1. Pain on the Outer Side of the Ankle

The pain may be constant or intermittent.
It often worsens with walking, running, or prolonged standing.

2. Feeling of Ankle Instability

Patients may feel that the ankle is unstable or unsteady.
It may feel as though the foot could easily twist during movement.
This sensation is often more noticeable on uneven surfaces.

3. Pain During Rapid Movements or Direction Changes

Symptoms may worsen while running, climbing stairs, or making sudden turns.
Twisting the foot may trigger discomfort.

4. Tenderness to Pressure

Pain is often reproduced by pressing on the outer side of the ankle.
Tenderness is usually localized to the sinus tarsi area.

5. Mild Swelling

Some patients may experience slight swelling around the affected region.
A feeling of fullness or discomfort may also be present.

6. Difficulty Walking for Long Periods

Pain tends to increase with prolonged use of the foot.
This can lead to fatigue and reduced mobility.

Diagnosis of Sinus Tarsi Syndrome

Diagnosis is based primarily on clinical evaluation while ruling out other causes of ankle pain.

First: Clinical Examination

1. Medical History

The healthcare provider may ask:

When did the pain begin?
Was there a previous ankle injury or sprain?
Does the pain worsen with walking, running, or physical activity?

2. Examination of the Pain Location

The outer side of the ankle is examined and gently pressed.
Localized tenderness within the sinus tarsi is considered a significant diagnostic finding.

3. Ankle Stability Testing

The foot is moved in different directions.
This helps assess ligament integrity and overall joint stability.

Second: Diagnostic Investigations

1. X-rays (X-ray)

Used primarily to rule out fractures, arthritis, or other bone abnormalities.
They usually do not show Sinus Tarsi Syndrome directly.

2. Magnetic Resonance Imaging (MRI)

Considered the most valuable imaging tool for diagnosis.
MRI can reveal:
- Inflammation within the sinus tarsi
- Ligament injuries
- Fluid accumulation or internal swelling

3. Diagnostic Injection

A local anesthetic is injected into the sinus tarsi region.
Temporary relief of pain following the injection strongly supports the diagnosis.

Potential Complications of Sinus Tarsi Syndrome

If the condition is left untreated or treatment is delayed, several complications may develop, primarily related to chronic pain and ankle instability.

1. Chronic Ankle Pain

Pain may persist for extended periods.
Symptoms may improve temporarily with rest but often return with activity.

2. Increased Ankle Instability

The ankle may become progressively weaker during walking and daily activities.
This increases the risk of future injuries.

3. Recurrent Ankle Sprains

Ongoing ligament weakness and inflammation make repeated sprains more likely.
Each new injury may worsen the condition.

4. Difficulty with Physical Activity

Running, sports participation, and long-distance walking may become painful.
This can reduce overall activity levels and quality of life.

5. Changes in Walking Pattern

Patients may alter their gait to avoid pain.
Over time, this may contribute to secondary pain in the knees, hips, or lower back.

6. Chronic Joint Inflammation

Persistent inflammation within the joint may gradually impair ankle function.
Long-term inflammation can contribute to ongoing discomfort and reduced mobility.

Medical Treatment for Sinus Tarsi Syndrome

The primary goals of medication therapy for Sinus Tarsi Syndrome are to relieve pain, reduce inflammation, and improve mobility. However, medications are typically used as part of a comprehensive treatment plan that also includes rest, physical therapy, and supportive measures.

1. Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

NSAIDs are considered the first-line medical treatment for Sinus Tarsi Syndrome.

Examples:

Ibuprofen
Diclofenac
Naproxen

Benefits:

Reduce inflammation within the sinus tarsi region
Relieve pain during walking and movement
Help minimize swelling when present

Note: These medications should generally be used for short periods and under medical supervision, especially in patients with stomach, kidney, or cardiovascular conditions.

2. Simple Analgesics

Example:

Paracetamol (Acetaminophen)

Benefits:

Effective for mild to moderate pain relief
May be used when NSAIDs are not suitable because of underlying health conditions

3. Topical Medications (Creams and Gels)

Examples:

Diclofenac gel
Other anti-inflammatory creams or ointments

Benefits:

Act directly at the site of pain
Help reduce localized inflammation
Suitable for mild cases or as an adjunct to other treatments

4. Corticosteroid Injections

Corticosteroid injections may be considered in moderate to severe cases and are administered directly into the sinus tarsi region.

Benefits:

Rapid reduction of inflammation
Longer-lasting pain relief compared with oral medications

Important Considerations:

Injections should not be repeated too frequently
They must be administered under the supervision of a qualified healthcare professional

5. Supportive Medications (Selected Cases)

Depending on the patient's symptoms, additional medications may be recommended, including:

Muscle relaxants for associated muscle tightness or spasms
Certain nerve-supporting vitamins when mild numbness or nerve irritation is present

Important Note

Medication alone is often insufficient because the underlying problem frequently involves:

Weakness of the ankle ligaments
Ankle joint instability

For this reason, medical treatment should be combined with:

✔ Relative rest

✔ Physical therapy and rehabilitation exercises

✔ Appropriate footwear or ankle support braces

Surgical Treatment of Sinus Tarsi Syndrome and Surgical Procedures

Surgery is not considered the first-line treatment for Sinus Tarsi Syndrome. It is generally reserved for patients who do not respond to conservative treatment—including medications, physical therapy, and bracing—or for those with significant ankle instability.

Primary Goals of Surgery

Remove the source of inflammation within the sinus tarsi
Improve ankle stability when ligament weakness is present
Reduce chronic pain and improve walking and overall function

Types of Surgical Procedures

1. Arthroscopic Surgery (Most Common)

Overview

This minimally invasive procedure uses a small camera and specialized instruments inserted through tiny incisions around the ankle.

Procedure Steps

Small incisions are made near the ankle
An arthroscope is inserted to visualize the sinus tarsi
Inflamed or scarred tissue is removed
Adhesions within the joint are released
The affected area is thoroughly cleaned
In some cases, joint surfaces are smoothed to improve movement

Advantages

Minimally invasive approach
Less postoperative pain
Faster recovery compared with open surgery

2. Open Surgery

Overview

An open surgical approach provides direct access to the sinus tarsi through a larger incision.

Procedure Steps

A surgical incision is made on the outer side of the ankle
The sinus tarsi region is exposed
Inflamed or damaged tissues are removed
The joint is thoroughly cleaned
Ligament repair is performed if necessary

Disadvantages

Longer recovery period
Greater postoperative discomfort compared with arthroscopy

3. Ligament Reconstruction

Overview

This procedure is recommended when ligament damage or weakness is responsible for ankle instability.

Procedure Steps

Damaged or weakened ligaments are identified
Ligaments are reinforced using strong sutures or tendon grafts
The ligaments are tightened and reconstructed to restore joint stability
The procedure may be combined with sinus tarsi debridement

4. Sinus Tarsi Decompression and Debridement

Overview

The goal is to reduce pressure within the inflamed area and improve joint function.

Procedure Steps

Removal of scar tissue and excess inflamed tissue
Reduction of inflammation within the sinus tarsi
Improvement of joint mobility and available space within the joint

5. Subtalar Joint Stabilization

Overview

This procedure is reserved for severe cases of subtalar joint instability.

Procedure Steps

Partial stabilization of the subtalar joint using surgical fixation techniques
Reduction of abnormal joint motion
Prevention of recurrent ankle sprains and instability episodes

Recovery After Surgery

Recovery Timeline

Rest is typically required for 2 to 6 weeks, depending on the type of procedure performed.
A splint, brace, or specialized orthopedic boot may be used during the recovery period.
Physical therapy is usually introduced gradually as healing progresses.
Return to normal activities and sports should occur gradually and under medical guidance.

Possible Complications (Rare)

Mild ankle joint stiffness
Temporary pain or swelling following surgery
Recurrence of symptoms if the underlying cause, such as ligament weakness or ankle instability, is not adequately addressed

Exercise Therapy for Sinus Tarsi Syndrome

Exercise therapy aims to do more than simply relieve pain. Its primary goals are to strengthen the ankle joint, improve balance, and reduce instability, which is often a major contributor to persistent symptoms.

Ankle Strengthening Exercises

1. Ankle Circles

How to Perform:

Sit comfortably and lift the foot off the ground.
Slowly move the ankle in circular motions.
Perform 10 repetitions in each direction.

Benefits:

Improves joint mobility
Reduces stiffness

2. Resistance Band Exercises

How to Perform:

Secure a resistance band around the foot.
Move the foot forward, backward, inward, and outward against resistance.

Benefits:

Strengthens ankle muscles
Improves joint stability

3. Calf Raises

How to Perform:

Stand on both feet.
Rise onto the toes and slowly lower back down.

Benefits:

Strengthens the calf and ankle muscles
Enhances balance and stability

Balance Exercises (Most Important)

4. Single-Leg Stand

How to Perform:

Stand on the affected foot.
Maintain balance for 20–30 seconds.
Use a wall or chair for support if needed.

Benefits:

Improves balance
Reduces the risk of recurrent ankle sprains

5. Standing on an Unstable Surface

How to Perform:

Stand on a cushion, balance pad, or other soft surface.
Practice balancing on one foot.

Benefits:

Trains the ankle to adapt to instability
Improves proprioception and joint control

Stretching Exercises

6. Calf Muscle Stretch

How to Perform:

Keep the foot flat on the ground.
Lean the body forward while keeping the heel in contact with the floor.

Benefits:

Reduces stress on the ankle joint

7. Achilles Tendon Stretch

How to Perform:

Use the same position as the calf stretch.
Increase the forward lean slightly.
Hold the stretch for 20–30 seconds.

Benefits:

Improves flexibility
May help reduce pain and stiffness

Important Exercise Guidelines

Reduce exercise intensity if pain increases significantly.
Progress gradually and consistently.
Perform exercises daily or at least 4–5 times per week.
In severe cases, exercises should ideally be supervised by a physical therapist.

Recovery Time for Sinus Tarsi Syndrome

Recovery varies depending on the severity of the condition, its underlying cause, and adherence to treatment recommendations.

Mild to Moderate Cases

Typical Cause:

Overuse injury
Mild ankle sprain

Treatment:

Rest
Medications
Exercise therapy

Recovery Time:

Approximately 2–6 weeks

Most patients begin to notice improvement within the first two weeks.

Moderate Cases with Mild Instability

Characteristics:

Recurrent ankle sprains
Mild ligament weakness

Treatment:

Physical therapy
Ankle support braces

Recovery Time:

Approximately 6–12 weeks

Improvement is usually gradual.

Chronic or Severe Cases

Characteristics:

Persistent pain
Significant ankle instability
Chronic inflammation

Recovery Time:

Approximately 3–6 months

Recovery may take longer if treatment recommendations are not followed consistently.

Recovery After Injections or Surgery

After Corticosteroid Injection:

Improvement may occur within a few days to several weeks.

After Surgery:

Initial recovery generally occurs within 2–6 weeks.
Full return to activity may require 2–3 months or longer, depending on the procedure and rehabilitation progress.

Factors That Promote Faster Recovery

Consistent participation in physical therapy
Wearing supportive footwear
Reducing stress on the affected foot and ankle
Using an ankle brace when recommended
Preventing recurrent ankle sprains

Factors That May Delay Recovery

Neglecting rehabilitation exercises
Continuing activities that overload the ankle
Returning to sports too early
Failure to address ligament weakness or ankle instability

Tips for Managing Sinus Tarsi Syndrome

Successful management focuses on reducing stress on the ankle joint, preventing recurrent injuries, and supporting the joint while inflammation resolves.