Definition
Stenosing Tenosynovitis of 1st dorsal compartment of wrist
Aetiology
- Repetitive thumb abduction with wrist ulnar deviation
- Postpartum and lactating women, linked to lifting an infant
- Direct trauma to the radial styloid
- Inflammatory arthritis
- Separate EPB subcompartment predisposes to stenosis
Epidemiology
- Most are middle-aged women
- Can develop in any with repetitive thumb abduction & extension combined with RD & UD movements
- Results from any mechanical irritation of foreign body, prominent bony surface, restricted fascial comp or abnormal muscle insertion to epitenon
Associated Conditions
- DM
- Pregnancy
- Hypothyroidism
- Gout
- Pseudogout
- RA
- Osteoarthritis
- PostTrauma
- TB
- Vascular disease
Anatomy
- 1st dorsal compartment runs over styloid process
- Runs in osteoligamentous tunnel of shallow groove in styloid & roofed by dorsal ligament attached by fibrous septa to bone
- Tunnel ~ 1cm long
- 1x APL & 1x EPB in only 20%
- 20-30% divided by vertical septa into 2 comps
- Ulnar for EPB
- Other for one or more slips of APL
- EPB phylogenetically young muscle
- Found only in humans & gorillas as separate from APL
- EPB absent 5-7%
- Larger APL has (up to 75%) 2-3 or more tendinous slips inserting variously into
- Base of 1st MC
- Trapezium
- Volar carpal ligament
- Opponens pollicis
- APB
Pathology
- Thickening of the extensor retinaculum over the first dorsal compartment
- Stenosis of the APL and EPB tendon sheath
- Myxoid degeneration and fibrocartilaginous metaplasia with little inflammatory infiltrate
Classification
- No accepted severity classification in clinical use
- Anatomical variants relevant to treatment include a separate EPB subcompartment
- Multiple APL tendon slips
History
- Radial wrist pain over the radial styloid with thumb use
- Pain with gripping, pinching and lifting
- Swelling over the first dorsal compartment
- Middle aged and postpartum women
- Occupation and hobbies with repetitive thumb movement
Examination
- Pain & swelling over styloid
- May radiate proximal & distal
- Finkelstein’s test +ve
- Crepitus
- Occasionally see triggering
- RD posture
- May have Bone Scan +ve
Investigations

- Clinical diagnosis
- X-rays exclude thumb CMC arthritis, scaphoid pathology and radial styloid lesions
- Ultrasound shows retinacular thickening, sheath fluid and intracompartmental septum
- Ultrasound guides injection into each subcompartment
Differential Diagnosis
- Basilar thumb arthrosis
- Scaphoid nonunion
- Intersection syndrome (ECRL/B crossed by APL & EPB)
- Wartenberg’s Syndrome (compression superficial branch radial n)
Treatment
Non-op
- Rest & Splint
- HCLA
- Harvey 71% relief with 1x injection
- Only 11% need surgery
- Prolonged conservative Treatment if condition involves pregnancy, DM etc
Operative
- Transverse or Longitudinal incision
- Blunt dissection to expose Superficial Radial Nerve
- Divide Annular Ligament » ensure all compartments decompressed
Complications
- Very Common
- 2 papers ~ 100%
- Radial n neuroma/ division
- Hypertrophic scar from longitudinal incision
- Volar subluxation of tendon if remove too much sheath
Prognosis
- Most resolve after one or two corticosteroid injections
- Separate EPB subcompartment is linked to injection failure
- Surgical release gives high rates of symptom relief
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.