Anterior Interosseous Syndrome – Causes, Symptoms & Best Physiotherapy Treatment at Physio360.

INTRODUCTION;

Anterior Interosseous Syndrome (AIS) is a rare but functionally limiting nerve condition affecting the forearm and hand. Though pain may be minimal or absent, patients often present with significant weakness, especially during fine motor activities like pinching, writing, or buttoning clothes. Early diagnosis and expert physiotherapy management are key to a fast and complete recovery.

At Physio360 Chennai, our experienced physiotherapists focus on root-cause diagnosis, nerve rehabilitation, and functional recovery, helping patients return to daily activities without surgery.

What is Anterior Interosseous Syndrome?

✔ Anterior Interosseous Syndrome is a pure motor neuropathy

✔ It involves compression or injury to the Anterior Interosseous Nerve (AIN)

✔ The AIN is a branch of the median nerve

✔ It supplies deep forearm muscles responsible for pinch and grip strength

Important note: Unlike carpal tunnel syndrome, there is NO sensory loss in AIS.

Muscles Affected in Anterior Interosseous Syndrome

The Anterior Interosseous Nerve innervates:

✅ Flexor Pollicis Longus (FPL) – thumb flexion

✅ Flexor Digitorum Profundus (Index & Middle finger) – finger tip bending

✅ Pronator Quadratus – forearm pronation

Weakness in these muscles leads to difficulty forming the “OK sign”.

Common Causes of Anterior Interosseous Syndrome

AIS may occur due to:

✔ Overuse injuries

✔ Repetitive forearm movements

✔ Prolonged computer or mobile use

✔ Trauma to the forearm or elbow

✔ Compression by fibrous bands or muscles

✔ Inflammatory neuritis

✔ Post-viral neuropathy

✔ Improper gym or sports techniques

At Physio360 Centre in Chennai, we carefully assess occupation, posture, activity level, and biomechanics to identify the exact cause.

Signs and Symptoms of Anterior Interosseous Syndrome

🔹 Inability to make a proper “OK sign”

🔹 Weak pinch grip

🔹 Difficulty holding small objects

🔹 Trouble writing or buttoning clothes

🔹 Weak thumb and index finger flexion

🔹 Forearm fatigue

🔹 Minimal or no pain

🔹 No numbness or tingling (pure motor nerve)

Red Flag: Sudden weakness without sensory loss should never be ignored.

Clinical Tests for Anterior Interosseous Syndrome

Physiotherapists at Physio360 perform specialised assessments such as:

✔ OK Sign Test

✔ Pinch Strength Test

✔ Manual Muscle Testing (FPL & FDP)

✔ Forearm Pronation Strength Test

✔ Functional Grip Assessment

✔ Differential diagnosis to rule out carpal tunnel syndrome and cervical radiculopathi

Diagnosis of Anterior Interosseous Syndrome

Diagnosis is based on:

Detailed clinical examination

Patient history

Nerve conduction studies (if required)

EMG (Electromyography)

MRI (in selected cases)

At Physio360 Chennai, we focus on clinical expertise, avoiding unnecessary investigations unless essential.

Best Physiotherapy Treatment for Anterior Interosseous Syndrome

Physiotherapy is the first-line and most effective treatment for AIS.

Physio360 Treatment Protocol Includes:

✅ Nerve mobilisation techniques

✅ Soft tissue release

✅ Myofascial release

✅ Forearm muscle activation

✅ Grip and pinch strengthening exercises

✅ Functional retraining

✅ Ergonomic correction

✅ Posture education

✅ Activity modification

✅ Home exercise program

Our goal is a fast recovery without surgery.

Exercise Rehabilitation at Physio360

🟢 Early Stage:

✔ Gentle nerve gliding exercises

✔ Pain-free range of motion

✔ Isometric muscle activation

🟢 Mid Stage:

✔ Strengthening of FPL & FDP

✔ Resistance exercises

✔ Hand function training

🟢 Advanced Stage:

✔ Grip endurance training

✔ Fine motor skill exercises

✔ Sport- or work-specific rehabilitation

All exercises are customised and supervised by the best physiotherapists at Physio360.

Do’s and Don’ts for Anterior Interosseous Syndrome

✅ Do’s

✔ Follow physiotherapist-guided exercises

✔ Maintain correct posture

✔ Take regular breaks during work

✔ Use ergonomic supports

✔ Attend regular physiotherapy sessions

❌ Don’ts

❌ Ignore weakness

❌ Continue repetitive strain activities

❌ Self-exercise without guidance

❌ Delay treatment

Recovery Time & Prognosis

✔ Most patients recover within 6–12 weeks

✔ Early physiotherapy leads to excellent outcomes

✔ Surgery is rarely required

✔ Compliance with exercises ensures long-term recovery

At Physio360 Centre in Chennai, we aim for complete nerve recovery and functional independence.

Why Choose Physio360 for Anterior Interosseous Syndrome?

⭐ Best physiotherapy clinic in Chennai

⭐ Experienced and skilled physiotherapists

⭐ Evidence-based treatment protocols

⭐ Advanced manual therapy techniques

⭐ Personalised rehabilitation programs

⭐ Fast recovery focus

⭐ Affordable and patient-friendly care

⭐ Trusted by athletes, professionals & families

When Should You See a Physiotherapist?

If you notice:

✔ Sudden hand weakness

✔ Difficulty pinching or gripping

✔ Trouble forming the OK sign

✔ Persistent forearm weakness

Consult early to avoid long-term disability.

Final Thoughts

Anterior Interosseous Syndrome may look minor, but untreated weakness can significantly affect daily activities and work performance. With early diagnosis and expert physiotherapy, recovery is smooth and complete.

Get Expert Treatment Today!

If you or your loved one is experiencing symptoms of Anterior Interosseous Syndrome, visit Physio360 Clinic, Chennai, for the best physiotherapy treatment, fast recovery, and long-term relief.

REFERENCE AND RESEARCH ARTICLE ;

1.Anterior interosseous nerve syndrome diagnosis and intraoperative findings: A case reporthttps://doi.org/10.1016/j.ijscr.2016.02.021.

2.Anterior Interosseous Syndromehttps://pubmed.ncbi.nlm.nih.gov/30247831/