Stenosing tenosynovitis

Stenosing tenosynovitis (often called trigger finger, trigger thumb, stenosing tenovaginitis) is a painful condition caused by the inflammation (tenosynovitis) and progressive restriction of the superficial and deep flexors fibrous tendon sheath adjacent to A1 pulley at a metacarpal head. Repetitive forceful compression, tensile stress, and resistive flexion, causes inflammation, swelling, and microtrauma, that results in thickening and stenosis (commonly a nodular formation) of the tendon distal to the pulley leading to a painful digital base, limitation of finger movements, triggering, snapping, locking, and deformity progressively.

Patients report a popping sound (at the PIP joint), morning stiffness with/without triggering, delayed and sometimes painful extension of the digit, and when more advanced, a locking position that requires manipulation to extends the affected finger. This condition more commonly affects the middle and ring fingers (occasionally the thumb), and the flexor rather than extensor tendons in the hand.^[1]

In rheumatic trigger finger (or in diabetes), more than one finger may be involved. Cases of stenosing peroneal tenosynovitis, have been reported where the patient presents with pain over the lateral malleolus, both with active and passive range of motion and no physical of radiographic evidence of instability.^[2][3]

Two common diagnoses fall into this category

• DeQuervain's Syndrome (affecting the first dorsal compartment of the wrist)^[4]
• Trigger finger (Occurs when a fibrous nodule develops in the digital flexor tendon) ^[5]

Causes

Most common cause is overuse from chronic repetitive activities using the hand or the involved finger. Examples include work activities (e.g., computer use, materials handling, hand surgeons) or recreational activities (e.g., knitting, golf, racket sports). Recently notable, the repetitive movements while using the controller of video games, has coned the name "Game-Boy Thumb" or from texting "texting tendonitis" when the thumb if affected.^{[citation needed]} Carpenters who use hammers suffer from this as well as those who continuously grip wood or other materials when cutting them due to having to use your hands as a clamp to hold things in place.

Primary stenosing tenosynovitis can be idiopathic, occurring in middle age women more frequently than in men, but can present also in infancy.

Secondary stenosing tenosynovitis, can be caused by disease or entities that causes connective tissue disorders such as:

• Rheumatoid arthritis & psoriatic arthritis, therefore the clinician must assess the hands for rheumatologic deformities and malalignment.
• Gout
• Diabetes Mellitus
• Amyloidosis
• Systemic Lupus Erythematosus

Others:

• Direct trauma to the site
• During postpartum period ^[6]
• Congenital

Clinical presentation

• More commonly presents in the 3rd and 4th hand digit, less commonly the thumb
• Produces a painful clicking as the inflamed tendon glides (by finger flexion and extension) through the thickened and stenosed sheath
• The digit may "lock" in flexion, extension, or in the middle range
• Determine if there is normal passive range of motion in the MP, PIP, and DIP joints (with true triggering there should be locking as the digit is passively taken through its range of movement)
• With chronic triggering, a proximal intrphalangeal flexion contracture (or interphalangeal flexion joint contracture) may develop
• Palpation may reveal a mobile, often tender, nodule within a tendon sheath of a finger or palm (which may imply a better prognosis with nonoperative treatment)
• Determine if the patient can flex and extend the digit past the triggering point without assistance

Differential Diagnosis

• Triggering at decussation of superficial flexor over the deep flexor
• MP joint locking
• Flexor digitorium profundus avulsion/rupture
• Extensor tendon rupture
• Failure of digit extension from chronic dislocation of the metacarphophalangeal
• Posterior interosseous nerve syndrome

Work up

No specific work up is defined. Stenosing tenosynovitis is a clinical diagnosis. However, if rheumatoid arthritis is suspected, laboratory evaluation of is granted (e.g. rheumatoid factor).

Imaging

As a rule, no imaging studies are needed to diagnose the condition. However, they can be valuable adjuvants to achieve a diagnosis. An ultrasound or MRI (most reliable study) can show increase thickness of the tendons involved. Thickening and hyper-vascularization of the pulley are the hallmarks of trigger fingers on sonography^[7]

Management

Occupational therapy is based on relieving the symptoms and reducing the inflammation. Overall cure rate, for dutifully applied non-operative treatment, is over 95%. Several modalities of treatment exists, depending on the chronicity and severity of the condition.

• Modification of hand activities
• Exercise & stretching
• Local heat
• Oral non-steroidal anti inflammatory drugs (NSAIDs) (e.g. Ibuprofen, Diclofenac topical)
• Extension splinting during sleep (custom metacarpophalangeal (MCP) joint blocking splint, which has reported better patient's symptomatic relief and functionality^[8] and a distal interphalangeal (DIP) joint blocking splint)
• Corticosteroid injections (very effective in approximately 70-75% of the cases ^[9] ) Treatment consists of injection of methylprednisolone often combined with anesthetic (lidocaine) at the site of maximal inflammation or tenderness. The infiltration of the affected site can be performed blinded or sonographycally guided, and often needs to be repeated 2 or three times to achieve remission. An irreducibly locked trigger, often associted with a flexion contracture of the PIP joint, should not be treated by injections.^[10]
• Transection of the fibrous annular pulley of the sheath

For symptoms that has been persistent or recurrent more than 6 months and/or unresponsive to conservative treatment, surgical release of the pulley may be indicated. Two approaches exists, open and percutaneous. The precutaneous approach, is preferred in some centers due to its reported shorter time of recuperation of motor function, less complications, and less painful.^[11] Complication of the surgical management include, persistent trigger finger, bowstringing, digital nerve injury, and continued triggering.^[12]

Of note, diabetes seems to be poor prognostic indicator for nonoperative treatment and may develop stiffness after surgical release.

There has been some anecdotal reports the use of tinctures containing cannabis extract results in anti-inflammatory relief, allowing the digits to extend in a normal fashion with minimal pain.^[13]

See also

• repetitive stress injury

References