Pronator Teres Syndrome
- Description / Cause
- Compression of the median nerve at the ligament of Struthers, lacertus fibrosis (bicipital aponeurosis), pronator teres, and arch of the flexor digitorum superficialis
- The deep fascia of the superficial head of the pronator teres is the only anatomic structure that causes compression of the median nerve in the upper forearm
- Trauma to median nerve at proximal forearm
- C5-8, T1 involvement
- Insidious onset
- Delay in diagnosis typically by 9 months to 2 years
- Prevalence / Risk factors
- 5th decade of life
- 4x more common in women
- Signs / Symptoms
- Pain
- Proximal anterior aspect of forearm
- Repeated pronation
- Repeated supination
- Exertional grasp work
- Examples: assembly line workers, carpenters, weightlifters, and tennis players
- Paresthesia
- Thumb
- Index finger
- Long fingers
- Palm
- Absence of nocturnal symptoms
- Weakness
- Insidious onset of pain to radial side of palm
- Tenderness over pronator teres
- Symptoms initiated or aggravated by prolonged and/or repetitive wrist and forearm activities
- Objective / Special Test
- MMT
- Possible weak muscles
- Abductor pollicis brevis
- Opponens pollicis
- Flexor pollicis brevis/longus
- Flexor digitorum proudness of index and long finger
- Pronator quadratus
- Flexor carpi radialis
- Site of compression testing
- Pronator teres
- Reproduction of symptoms with resisted pronation, with the forearm in neutral, as the elbow is gradually extended
- Lacertus fibrosus
- Reproduction of symptoms with resisted elbow flexion at 120-130 degrees flexion with the forearm in maximal supination
- Flexor digitorum superficialis
- Reproduction of symptoms with resisted flexion of the proximal IP joint of the long finger
- Pronator compression test
- Positive test is indicated by reproduction of paresthesia in the lateral 3 1/2 digits in 30 seconds or less, while the uninvolved limb remains asymptomatic
- Tinel's sign
- May be positive but only if symptoms have existed for more than 4 months
- 70% sensitivity
- 98% specificity
- 35 LR+
- 0.31 LR-
- Phalen's test
- Should be negative if suspecting pronator teres syndrome
- Rarely electrodiagnostic testing completed
- Pronator sign test
- Upper Limb Tension Test
- Median nerve bias
- 50% sensitivity
- 86% specificity
- 3.5 LR+
- 0.58 LR-
- Treatment / Interventions
- With conservative care, 50% of patients report recovery in 4 months
- Rest/Immobilization
- Elbow at 90 degrees
- Slight forearm pronation
- Slight wrist flexion
- Worn for 2 weeks with removal for gentle ROM
- Activity modifications
- Patient education
- Modalities
- Ultrasound
- Electrical stimulation
- Iontophoresis
- Modalities have not been studied for direct use for pronator teres syndrome
- Tendon/nerve gliding techniques
- Surgical decompression
- After 8-12 weeks of conservative care with no significant change in symptoms
- Days 0-7: splinting, non-weightbearing
- Days 7-10: remove sutures, discontinue splinting as prescribed, start gentle ROM exercises
- Weeks 4-6: begin strengthening exercises
- 85-90% good to excellent recovery
- Differential diagnosis
- Carpal tunnel syndrome
- Cervical radiculitis
- Thoracic outlet syndrome
- Brachial plexus neuritis
References
- Fuss F, Wurzl G. Median nerve entrapment. Pronator teres syndrome. Surgical anatomy and correlation with symptom patterns. Surgical And Radiologic Anatomy: SRA [serial online]. 1990;12(4):267-271. Available from: MEDLINE, Ipswich, MA. Accessed July 8, 2015.
- Lee M, LaStayo P. Pronator syndrome and other nerve compressions that mimic carpal tunnel syndrome. Journal Of Orthopaedic & Sports Physical Therapy [serial online]. October 2004;34(10):601-609. Available from: CINAHL Plus with Full Text, Ipswich, MA. Accessed July 5, 2015.
- Rehak D. Pronator syndrome. Clinics In Sports Medicine [serial online]. January 1, 2001;20:531-540. Available from: ScienceDirect, Ipswich, MA. Accessed July 8, 2015.
- Robertson E, Reimche, D. Differential Diagnosis for Various Neuropathies at the Elbow. Accessed June 30, 2015.
- Zancolli I, Zancolli I, Perrotto C. Surgical technique: New Mini-invasive Decompression for Pronator Teres Syndrome. Journal Of Hand Surgery [serial online]. August 1, 2012;37:1706-1710. Available from: ScienceDirect, Ipswich, MA. Accessed July 7, 2015.
Acknowledgements:
David Funk, Student Physical Therapist at A.T. Still University
Ethan Hunke, Student Physical Therapist at A.T. Still University
Morgan Johnson, Student Physical Therapist at A.T. Still University
Ed Nheiu, Student Physical Therapist at A.T. Still University
Lindsay Walczak, Student Physical Therapist at A.T. Still University
Last edited: July 13, 2015