Tenosynovitis is inflammation of the synovial sheath that surrounds a tendon. Most tendons in the hand and wrist pass through synovial sheaths that produce lubricating fluid, allowing tendons to glide smoothly during movement. When these sheaths become inflamed, the resulting swelling and friction cause pain, stiffness, and impaired movement.
Tenosynovitis is closely related to tendinopathy and tendon tears — in many cases both the tendon and its sheath are affected simultaneously. Inflammation of the extensor carpi ulnaris (ECU) tendon sheath on the ulnar side of the wrist can occur alongside ulnar abutment syndrome or TFCC tears, and MRI is often needed to distinguish which structure is the primary pain generator.
Causes
- Overuse and repetitive motion: The most common cause — particularly for De Quervain's tenosynovitis and trigger finger. Repetitive gripping, pinching, typing, texting, or tool use irritates tendon sheaths over time.
- De Quervain's tenosynovitis: Inflammation of the sheath surrounding the abductor pollicis longus and extensor pollicis brevis tendons on the thumb side of the wrist. Common in new mothers lifting babies ("mommy thumb"), frequent texters, and certain occupational groups.
- Trigger finger (stenosing tenosynovitis): Thickening of the flexor tendon sheath at the A1 pulley in the palm, causing the tendon to catch as it moves through the narrowed opening.
- Infection (septic tenosynovitis): Bacterial infection of a tendon sheath, typically from a puncture wound or bite to the hand. This is a surgical emergency.
- Inflammatory conditions: Rheumatoid arthritis, psoriatic arthritis, and other autoimmune conditions frequently cause tenosynovitis affecting multiple sheaths.
- Diabetes: Patients with diabetes have a significantly higher risk of trigger finger and other forms of tenosynovitis.
- Hormonal factors: Pregnancy and postpartum hormonal changes increase the risk of De Quervain's tenosynovitis.
- Thyroid disease and amyloidosis: Both conditions predispose to tenosynovitis.
- Trauma: Direct injury to a tendon sheath — including crush injuries and lacerations — can trigger acute tenosynovitis.
- Anatomic factors: An unusually narrow first dorsal compartment or an intracompartmental septum may predispose to De Quervain's tenosynovitis.
Symptoms
Symptoms vary depending on which tendon sheath is affected:
- Pain: Along the course of the affected tendon, worsened by movement or activity.
- Swelling and tenderness: Visible or palpable swelling with tenderness to touch over the inflamed sheath.
- Stiffness: Difficulty moving the affected finger or thumb, especially after periods of rest.
- Crepitus: A creaking or grating sensation as the tendon moves through the inflamed sheath.
- Triggering or locking: In trigger finger, the affected finger catches or locks in a bent position, requiring force to straighten — often with a painful snap or click. A tender nodule may be felt in the palm.
- Reduced range of motion and weakness: Limitation in normal movement with reduced grip or pinch strength.
- De Quervain's specific signs: Pain on the thumb side of the wrist radiating into the thumb or up the forearm, worsened by pinching or grasping. Positive Finkelstein test — sharp pain when the thumb is tucked into the palm and the wrist bent toward the little finger — is the hallmark clinical finding.
- Kanavel's signs (septic tenosynovitis): Fusiform (sausage-shaped) swelling of the finger; finger held in slight flexion; severe tenderness along the entire flexor tendon sheath; severe pain with passive extension of the finger. These four signs indicate a serious infection requiring emergency treatment.
Diagnosis
Physical examination includes inspection for swelling, palpation for tenderness along the tendon sheath, range of motion assessment, and specific provocative tests. The Finkelstein test is the primary clinical test for De Quervain's tenosynovitis. Kanavel's four signs should be assessed whenever infectious tenosynovitis is suspected — their presence mandates urgent surgical referral.
When the diagnosis is uncertain, when multiple structures may be involved, or when surgical planning is needed, a dedicated wrist MRI or hand MRI is the most informative imaging study. MRI provides detailed images of the tendon, its sheath, and surrounding soft tissues — identifying sheath thickening, fluid accumulation within the sheath, and any associated tendon tears or adjacent pathology such as TFCC injury. Ultrasound is a useful adjunct, particularly for real-time sheath evaluation and guiding injection treatments. Laboratory tests — including CBC, ESR, CRP, and culture of aspirated sheath fluid — are important when infection or systemic inflammatory disease is suspected.
Classification
Common forms of hand and wrist tenosynovitis include:
- De Quervain's tenosynovitis: First dorsal compartment — abductor pollicis longus and extensor pollicis brevis tendons on the thumb side of the wrist.
- Trigger finger (stenosing flexor tenosynovitis): Flexor tendons at the A1 pulley in the palm.
- Intersection syndrome: Inflammation where the first dorsal compartment tendons cross over the second dorsal compartment tendons on the back of the forearm.
- Extensor carpi ulnaris (ECU) tenosynovitis: Sixth dorsal compartment — ulnar side of the wrist, often associated with ulnar abutment or TFCC pathology.
- Flexor carpi radialis (FCR) tenosynovitis: Radial (thumb) side of the wrist at the wrist crease.
- Septic tenosynovitis: Bacterial infection of a tendon sheath — most commonly the flexor tendons of the fingers. Surgical emergency.
- Rheumatoid tenosynovitis: Associated with rheumatoid arthritis — can affect multiple tendon sheaths simultaneously and lead to tendon rupture if untreated.
Treatments
Treatment varies based on the type of tenosynovitis, severity, and underlying cause.
Conservative treatment: Rest and activity modification to reduce sheath irritation, splinting (thumb spica splint for De Quervain's, finger extension splint for trigger finger), ice for acute inflammation, NSAIDs for pain and swelling, and hand therapy with stretching and ergonomic advice. Corticosteroid injection into the affected tendon sheath is highly effective for De Quervain's and trigger finger — many patients experience significant and lasting relief from one or two injections.
Treatment of underlying conditions
For tenosynovitis associated with rheumatoid arthritis or other systemic disease, treatment of the underlying condition with appropriate disease-modifying medications is essential. Optimizing diabetes control can reduce trigger finger recurrence and improve response to treatment.
Emergency treatment for septic tenosynovitis
Septic tenosynovitis requires urgent surgical drainage and irrigation of the infected tendon sheath — delay risks irreversible tendon damage and permanent loss of hand function. Intravenous antibiotics are initiated immediately and continued based on culture results.
Surgical treatment when conservative measures fail
- De Quervain's release: Surgical division of the first dorsal compartment roof to decompress the affected tendons. Outpatient procedure with excellent outcomes.
- Trigger finger release: Division of the A1 pulley to allow free tendon gliding — performed open or percutaneously with high success rates.
- Tenosynovectomy: Removal of diseased or thickened tendon sheath — particularly for rheumatoid tenosynovitis or chronic cases unresponsive to other treatment.
Recovery
After surgical release, most patients resume normal activities within a few weeks. Hand therapy restores range of motion and strength. Ergonomic modifications and stretching programs help reduce the risk of recurrence.
Get an MRI to Confirm Your Diagnosis
Before surgical planning or starting treatment, a clear MRI diagnosis ensures the right path forward. First Look MRI offers self-pay Wrist MRI scans — no doctor's order or insurance required — at our locations in Georgia, Texas, and Colorado.