From the Guidelines
Carpal tunnel syndrome and trigger finger are distinct hand conditions with different causes and symptoms, and the most recent evidence from 2024 supports the use of ultrasound (US) for diagnosis and treatment guidance 1.
Key Differences
- Carpal tunnel syndrome occurs when the median nerve is compressed as it passes through the carpal tunnel in the wrist, causing numbness, tingling, and weakness in the thumb, index, middle, and half of the ring finger.
- Trigger finger involves a finger or thumb getting stuck in a bent position due to inflammation of the tendon sheath, causing painful clicking or popping when straightening the digit.
Diagnosis and Treatment
- Carpal tunnel syndrome diagnosis can be confirmed using US, which is highly sensitive and specific for the diagnosis of CTS, especially when compared to clinical assessment and electrophysiologic studies 1.
- Treatment for carpal tunnel syndrome typically includes wrist splinting, anti-inflammatory medications like ibuprofen, corticosteroid injections, and in severe cases, surgery to release the transverse carpal ligament.
- Trigger finger treatment includes rest, NSAIDs like naproxen, steroid injections into the tendon sheath, and possibly surgery to release the A1 pulley if conservative measures fail.
Importance of Ultrasound
- US is a useful technique for examining extra-articular soft tissues, such as suspected ganglion cysts, and can also be used to diagnose abnormalities of the flexor and extensor tendons and tendon sheaths 1.
- US can identify synovitis, joint effusion, tenosynovitis, tendinopathy and tendon injury, CTS, metacarpophalangeal joint collateral ligament injury, extensor hood injury, and retained foreign body 1.
- The American College of Rheumatology has concluded that there is reasonable evidence to support the use of musculoskeletal US in patients without definitive diagnosis presenting with pain, swelling, or mechanical symptoms of the wrist 1.
From the Research
Difference between Carpal Tunnel Syndrome (CTS) and Trigger Finger (Stenosing Tenosynovitis)
- Carpal tunnel syndrome is characterized by numbness and tingling in the thumb and the index, middle, and radial ring fingers and by weakness of thumb opposition when severe 2.
- Trigger finger, on the other hand, involves abnormal resistance to smooth flexion and extension ("triggering") of the affected finger, affecting up to 20% of adults with diabetes and approximately 2% of the general population 2.
- The symptoms of CTS and trigger finger can be similar, but the key difference lies in the location and nature of the symptoms: CTS affects the median nerve in the wrist, while trigger finger affects the tendons in the fingers 3, 4.
Diagnosis and Treatment
- Diagnosis of CTS can be made through physical examination maneuvers such as the Durkan test, and electrodiagnostic testing can confirm the diagnosis 2, 3.
- Trigger finger can be diagnosed through clinical examination, and treatment options include steroid injection, splinting, and surgical release 2, 4.
- Both conditions can be treated with conservative therapies such as splinting and steroid injections, but surgical intervention may be necessary for severe or recurrent cases 2, 3, 4.
Association between CTS and Trigger Finger
- Studies have shown that CTS and trigger finger can occur together in the same patient, with a higher prevalence of CTS in patients with trigger finger than in the general population 5, 6.
- The exact mechanism of this association is unclear, but it is thought to be related to common pathophysiological factors such as tendon and nerve inflammation 6.
- Evaluation for both conditions is recommended at the time of presentation, as the symptoms of one condition may be more prominent than the other 5.