Access Keys:
Skip to content (Access Key - 0)

Pronator Syndrome

Introduction

Uncommon syndrome of pain, easy fatigability, and/or sensory deficits resulting from entrapment of the median nerve near the elbow.

Anatomy

Potential sites of impingement include:

  • lacertus fibrosus
  • between the two heads of a hypertrophied pronator teres muscle
  • intramuscular tendinous bands
  • fascial bands between the superficial and deep heads
  • vascular leashes
  • fibrous arch of the flexor digitorum superficialis.

Pathogenesis

Natural History

Common in weight lifting and occupations requiring repetitive pronation of the forearm

Patient History and Physical Findings

History:

  • forearm dysesthesias
  • dysesthesias in the palmar triangle and or thenar eminence
  • easy fatigability of forearm muscles
  • signs of median neuropathy localized to the forearm and hand
  • Numbness in median nerve distribution after repetitive pronation
  • nocturnal awakening due to pain/numbness is uncommon, in contrast to carpal tunnel syndrome

Physical Findings:

  • Provocative tests:
    • Resisted pronation with the elbow in extension
    • Resisted elbow flexion
    • Resisted contraction of the FDS to the long finger.
  • Anterior interosseous nerve function is typically spared, despite the fact this nerve branches from the median nerve near the sites of potential impingement.
  • Carpal tunnel provocative tests are negative
  • Tenderness in proximal portion of pronator teres muscle
  • Positive Tinel sign at proximal edge of pronator teres muscle

Imaging and Diagnostic Studies

Radiography:

Electrophysiologic testing:

  • Useful for distinguishing other peripheral nerve disorders with similar presentations
  • In 15-20% of patients with pronator teres syndrome, electrophysiologic testing will identify a non-localizable median nerve lesion. In fewer cases it will localize the site of the lesion
    .
  • If EMG ordered, request a needle placed in the flexor pollicus longus

Differential Diagnosis

  • cervical radiculopathy
  • thoracic outlet syndrome
  • brachial plexus neuritis (Parsonage Turner Syndrome)
  • overuse injury
  • carpal tunnel syndrome
  • Anterior interosseus syndrome (Kiloh-Nevin syndrome)

Treatment

Medical therapy:

Nonoperative treatment:

  • Surgery is usually not necessary as this condition can typically be treated with activity modification.

Operative treatment:

  • Surgical exploration and release of impinging structures. Potential sites of impingement include the lacertus fibrosus, between the two heads of a hypertrophied pronator teres muscle (requires release of the humeral head), intramuscular tendinous bands, fascial bands between the superficial and deep heads, vascular leashes, fibrous arch of the flexor digitorum superficialis.
  • One series of 36 patients treated surgically, 8 had excellent results, 20 had good results, 5 had fair results and 3 remained unchanged
    .

Pearls and Pitfalls

Postoperative Care

Outcome

Complications

References

JAAOS Articles

Resources on Pronator Syndrome from JAAOS. [Sign Up and build your orthopaedic network].

Refresh
The license could not be verified: License Certificate has expired!
Orthopaedic Web Links

Internet resources validated by OrthopaedicWebLinks.com

Refresh
The license could not be verified: License Certificate has expired!
Related Content

Resources on Pronator Syndrome and related topics in OrthopaedicsOne spaces.