What is the recommended treatment for a patient with first extensor tenosynovitis?

Treatment of First Extensor Tenosynovitis (De Quervain's Tenosynovitis)

Begin with thumb spica splinting combined with corticosteroid injection, as this combination provides superior outcomes compared to either treatment alone. 1, 2, 3

First-Line Conservative Management

The initial treatment approach should include multiple modalities simultaneously:

Immobilization

• Apply thumb spica splinting immediately to immobilize the first dorsal compartment and rest the affected abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons 1, 2
• Continue splinting throughout the treatment course, not just initially 1
• Avoid complete immobilization; allow activities that don't worsen pain to prevent muscular atrophy 2

Pharmacologic Pain Management

• NSAIDs (oral or topical) should be started for pain relief, with topical formulations preferred to eliminate gastrointestinal hemorrhage risk while maintaining efficacy 1, 2
• Cryotherapy applied through a wet towel for 10-minute periods provides effective short-term pain relief 2

Corticosteroid Injection

• Corticosteroid injection is significantly more effective than immobilization alone (relative risk of treatment success: 1.61), and combining injection with splinting is even more effective (relative risk: 2.15 compared to immobilization alone) 3
• The FDA approves triamcinolone acetonide for acute nonspecific tenosynovitis, with initial doses of 2.5-5 mg for smaller areas 4
• Ultrasound guidance is recommended for injection accuracy 1
• Inject into the tendon sheath, NOT the tendon substance, as intratendinous injection may inhibit healing, reduce tensile strength, and predispose to spontaneous rupture 2, 4
• Limit to a maximum of 2-3 corticosteroid injections 1

Adjunctive Physical Therapy

Once acute inflammation subsides:

• Therapeutic ultrasound may decrease pain and increase collagen synthesis, though evidence of consistent benefit is weak 1, 2
• Phonophoresis may deliver topical medications to affected tissues, though high-quality evidence is limited 2

Expected Timeline and Prognosis

• Approximately 80% of patients fully recover within 3-6 months with conservative management 1, 2
• Continue conservative therapy for at least 3-6 months before considering surgical intervention 1, 2

Surgical Management

Reserve surgery for patients who fail 3-6 months of consistent conservative therapy 1, 2

Surgical indications include:

• Failure of conservative management after 3-6 months of treatment including splinting, NSAIDs, activity modification, and at least 2 corticosteroid injections 1
• Persistent pain and functional impairment despite maximal conservative therapy 5

Surgical technique considerations:

• Release of the first dorsal compartment is the standard procedure 5
• Ultrasound can detect subcompartmentalization within the first dorsal compartment, which may affect surgical planning as accessory tendons or septum within the compartment can lead to incomplete decompression if not addressed 1
• Both traditional dorsal and novel volar approaches have been described, with the volar approach potentially decreasing risk of iatrogenic sensory nerve injury 6

Critical Diagnostic Considerations

Before finalizing the diagnosis:

• Confirm diagnosis with ultrasound if clinical examination is equivocal, looking for thickened, hypoechoic tenosynovial sheath surrounding the APL and EPB tendons 1
• Rule out differential diagnoses including intersection syndrome, first carpometacarpal joint osteoarthritis, and scaphoid fracture 1
• If diffuse wrist swelling extends beyond the first dorsal compartment or multiple tendons are involved, evaluate for underlying inflammatory arthritis such as rheumatoid arthritis, as flexor/extensor tenosynovitis can be associated with systemic inflammatory conditions 7, 1

Common Pitfalls to Avoid

• Never inject corticosteroid into the tendon substance itself—always target the tendon sheath to prevent tendon rupture 2, 4
• Avoid mislabeling chronic cases as "tendinitis" when they represent degenerative tendinopathy ("tendinosis") 7
• Don't proceed to surgery prematurely; patience with conservative therapy is warranted given the 80% success rate 1, 2
• Be cautious injecting in the deltoid region to avoid tissue atrophy from peritendinous injection 4