How does trigger finger (stenosing tenosynovitis) of the thumb affect thumb mobility?

From the Guidelines

Trigger finger of the thumb significantly restricts thumb mobility, causing pain, catching, locking, or sticking when attempting to bend or straighten the thumb, and if left untreated, can lead to greater mobility restrictions and potentially permanent stiffness. The condition occurs when inflammation narrows the space within the tendon sheath, creating a mismatch between the tendon and its surrounding sheath, as a result, the thumb may become stuck in a bent position and then suddenly pop straight (triggering), or it may become locked in a bent position entirely 1.

Key Points to Consider

• The restricted mobility affects everyday activities requiring thumb dexterity, such as gripping objects, writing, typing, or manipulating small items.
• Treatment options include rest, splinting, anti-inflammatory medications, corticosteroid injections into the tendon sheath, and in severe cases, surgery to release the constricted tendon sheath.
• According to the EULAR recommendations for the management of hand osteoarthritis, exercises to improve function and muscle strength, as well as to reduce pain, should be considered for every patient, and orthoses should be considered for symptom relief in patients with thumb base OA 1.
• The EULAR recommendations also suggest that topical treatments are preferred over systemic treatments because of safety reasons, and oral analgesics, particularly NSAIDs, should be considered for a limited duration for relief of symptoms 1.

Management and Treatment

• The goal of treatment is to reduce pain and improve mobility, and the choice of treatment depends on the severity of the condition and the patient's individual needs.
• In some cases, surgery may be necessary to release the constricted tendon sheath and improve mobility, as recommended by the EULAR guidelines for patients with structural abnormalities when other treatment modalities have not been sufficiently effective in relieving pain 1.

From the Research

Trigger Finger of Thumb and Thumb Mobility

• Trigger finger of the thumb is a condition that affects the mobility of the thumb, causing pain and restricted movement 2, 3, 4, 5.
• The condition occurs when the movement of the flexor tendon through the first annular (A1) pulley is impaired, leading to degeneration, inflammation, and swelling 2.
• Studies have shown that trigger finger of the thumb can result in a limited range of motion, with patients complaining of pain on motion or triggering 3.

Comparison of Trigger Finger and Trigger Thumb

• A study comparing the surgical outcomes of trigger finger and trigger thumb found that trigger fingers had a significantly longer duration before surgery and took longer for symptoms to subside 3.
• The same study found that trigger fingers had a higher incidence of flexion contracture of the PIP joint, which may contribute to poorer surgical outcomes compared to trigger thumb 3.

Treatment Options and Thumb Mobility

• Various treatment options are available for trigger finger of the thumb, including non-steroidal anti-inflammatory drugs (NSAIDs), steroid injections, and surgery 2, 4, 5.
• A study comparing the efficacy of steroid injection and NSAID injection found that both treatments were effective in reducing symptoms, with no significant difference in success rate between the two treatments at 3 months 5.
• Another study found that surgical treatment had significantly better efficacy in success rate compared to steroid injection at all follow-ups 4.

Effect of Treatment on Thumb Mobility

• The effect of treatment on thumb mobility is not explicitly stated in the studies, but it can be inferred that successful treatment of trigger finger of the thumb can improve thumb mobility by reducing pain and inflammation 2, 3, 4, 5.
• A study found that there was little to no difference between groups in mean total active motion at 24 weeks, suggesting that treatment may not have a significant impact on thumb mobility in the short term 2.