Jay T. Bridgeman and Sanjiv Naidu
DEFINITION
Synovium lines the joint spaces and tendon sheaths.
It secretes lubricant (synovial fluid) needed for tendon gliding and reduces friction in synovial joint motion.
Tendons may be both extraand intrasynovial.
Flexor tendons in the carpal tunnel have the added feature of subsynovial connective tissue, which can become inflamed.
Tenosynovitis is inflammation of the tendon sheath in extrasynovial tendons, and inflammation of the synovial lining in intrasynovial tendons.3
ANATOMY
The extensor tendons lie under the dorsal retinaculum in six separate compartments. These may be divided into the extensor tendon zones. The portion of the extensor tendon that lies under the dorsal retinaculum is lined with a synovial sheath (FIG 1A).
The first extensor tendons originate as outcropper muscles from the distal third of the forearm and cross over the second extensor compartment tendons—the extensor carpi radialis longus (ECRL) and the extensor carpi radialis brevis—distally at the level of the wrist about 4 cm proximal to the radial styloid.
The extensor pollicis longus (EPL) in the third extensor compartment makes an acute angle at the Lister's tubercle at the level of the wrist.
The fourth extensor compartment tendons—the extensor digitorum communis and the extensor indicis proprius—lie under a broad retinaculum. The deep branch of the posterior interosseous nerve courses deep to the fourth extensor compartment.
The extensor digitorum quinti in the fifth extensor compartment often is the only tendon to motor the small finger metacarpophalangeal (MCP) joint in the act of extension.
The extensor carpi ulnaris (ECU) tendon in the sixth compartment lies in a fibro-osseous tunnel and is intimately held in the ulnar groove by a subsheath that is critical for distal radioulnar joint stability.
The wrist flexor tendons—the flexor carpi radialis (FCR), the palmaris longus, and the flexor carpi ulnaris—are extrasynovial tendons.
The FCR passes through a tight fibro-osseous tunnel in the trapezium before inserting on the base of the second metacarpal (FIG 1B,C).
The digital flexor tendons lie under the transverse carpal ligament in the carpal tunnel. Unlike digital extensor tendons, flexor tendons are almost entirely intrasynovial.
The flexor tendons in the digits lie in a fibro-osseous canal formed by the annular and cruciate ligaments.2
PATHOGENESIS
Rheumatoid arthritis is a disease of synovial tissue that can lead to inflammatory tensosynovitis.
Flexor and extensor tenosynovitis is most commonly a sequlae of rheumatoid arthritis.
Rheumatoid arthritis causes formation of hypertrophic synovium in the joint spaces, thereby destabilizing joints. The hypertrophic synovium invades the tendon sheaths and synovial lining of all tendons.3
NATURAL HISTORY
Inflammatory tenosynovitis usually is painless and can be the first sign of rheumatoid arthritis.
The dorsal and volar wrist, as well as the volar digits, are most commonly affected.
FIG 1 • A. Extensor compartments of the hand. B. Flexor tendons. C. Carpal tunnel.
The synovial tissue proliferates in the tendon sheath and eventually may invade the tendon.
The end result is weakening and rupture of the tendon.3
PATIENT HISTORY AND PHYSICAL FINDINGS
Tenosynovitis of the first extensor compartment reveals thickening of the extensor pollicis brevis and abductor pollicis longus tendon sheaths at the radial styloid.
This thickening can produce a positive Finkelstein's test: ulnar wrist abduction of a hand in a fist position, causing pain along the first extensor compartment.
Second compartment extensor tenosynovitis presents with painless swelling of the dorsum of the wrist 4 cm proximal to the radial styloid. There is focal tenderness to palpation with swelling and positive Tinel sign of the sensory branch of the radial nerve.
Third extensor compartment tenosynovitis usually presents with rupture of the EPL tendon.
This results in inability to raise the thumb when the hand is placed flat on a table.
Fourth extensor compartment tenosynovitis presents with focal swelling in extensor zone 7 along with multiple tendon ruptures (FIG 2).
Fifth extensor compartment tenosynovitis usually is accompanied by dorsal distal ulna instability and tendon rupture.
Sixth extensor compartment tenosynovitis is manifested as ECU instability in addition to significant intrasynovial inflammation at the level of the ulnar styloid.
Pain at the wrist indicates that the radiocarpal or radioulnar joint is affected.
Flexor tenosynovitis at the wrist can cause median nerve compression in the carpal tunnel, as well as decreased active and passive range of motion of the fingers.
Flexor tenosynovitis of the digits can cause triggering.2
The flexor tendon that most commonly ruptures due to rheumatoid arthritis is the flexor pollicis longus. This is termed the Mannerfelt lesion and results in loss of thumb interphalangeal joint flexion.
The following examinations, all of which may detect weakness or rupture, are graded on a scale of 0 to 5:
First dorsal compartment (abductor pollicis longus and extensor pollicis brevis): abduct the thumb radially.
FIG 2 • Dorsal swelling secondary to extensor tenosynovitis
Second extensor compartment (extensor carpi radialis longus and extensor carpi radialis brevis): extend and radially deviate the wrist.
Third extensor compartment (EPL): with the hand flat on table surface, extend the thumb.
Fourth extensor compartment
Extensor digitorum communis: extend the fingers at the MCP joints.
Extensor indicis proprius: extend index finger at the MCP joint with other fingers flexed.
Fifth extensor compartment (extensor digitorum quinti): extend the small finger at the MCP joints with other fingers flexed.
Sixth extensor compartment (ECU): extend and ulnarly deviate the wrist.
FCR: wrist flexion and radial deviation
Flexor carpi ulnaris: wrist flexion and ulnar deviation
Flexor digitorum superficialis: flex the proximal interphalangeal joint while holding adjacent fingers extended.
Flexor digitorum profundus: block the proximal interphalangeal joint in extension and flex the distal interphalangeal joint.
Flexor pollicis longus: flex the thumb interphalangeal joint against resistance.
IMAGING AND OTHER DIAGNOSTIC STUDIES
MRI may be useful to evaluate low-grade tenosynovitis and mechanical dysfunction of the fibro-osseous digital pulley system.
In general, flexor or extensor tenosynovitis is a clinical diagnosis made on physical findings.
DIFFERENTIAL DIAGNOSIS
Extensor tendon weakness
Rupture of sagittal bands
Posterior interosseous nerve palsy
Intrinsic muscle tightness or contracture
Extensor tendon rupture
Flexor tendon weakness
Flexor tendon rupture
Nerve palsy (median nerve, anterior interosseous nerve, ulnar nerve)
NONOPERATIVE MANAGEMENT
Medical control of rheumatoid arthritis
Splinting
Cortisone injections are only very rarely indicated due to the risk of tendon rupture.
FIG 3 • A. Dorsal extensor tenosynovitis. B. Volar flexor tenosynovitis. C. Zigzag (Brunner) approach to digital flexor tendons.
SURGICAL MANAGEMENT
Tenosynovectomy is indicated if no improvement is observed after 4 to 6 months of adequate medical treatment or if tendon ruptures are detected.3
Flexor tenosynovectomy is relatively indicated if active digit motion becomes worse than passive motion.3
Preoperative Planning
Consider withholding rheumatoid medications (eg, methotrexate, Etanercept, Imuran) 1 week before and 1 week after surgery.3
Positioning
The patient is positioned supine with an armboard.
Approach
For an extensor tenosynovectomy, the wrist dorsal midline approach is used (FIG 3A).
For a flexor tenosynovectomy, the wrist volar approach to the carpal tunnel is chosen (FIG 3B).
A digital tenosynovectomy is done using the volar zigzag approach to the digits (FIG 3C).
TECHNIQUES
EXTENSOR TENOSYNOVECTOMY
A straight longitudinal incision is made.
Full-thickness skin flaps are created, exposing the extensor retinaculum (TECH FIG 1A).
A straight longitudinal incision is made of the extensor retinaculum over the third compartment.
Transverse incisions are made over the proximal and distal borders of the retinaculum, creating a radially based flap.
Divide the vertical septum, opening each extensor compartment.
Remove hypetrophic synovium from each tendon sheath with a rongeur or by sharp dissection (TECH FIG 1B).
Frayed tendons are repaired with fine interrupted sutures.
Tendons at risk for rupture are sutured to adjacent tendons.
If synovitis of the wrist is encountered, wrist synovectomy is performed, and, if possible, the capsule is closed.
The distal ulna is resected if it is prominent dorsally or if significant distal radioulnar joint arthrosis is noted.
The retinaculum is passed deep to the extensor tendons and sutured (TECH FIG 1C,D).
Suturing a portion of the retinaculum over the extensor tendons prevents bowstringing.2
TECH FIG 1 • A. Dorsal midline approach. B. Débridement of dorsal tenosynovitis.C. Sharply elevating the dorsal retinaculum. D. Closing the dorsal retinaculum.
FLEXOR TENOSYNOVECTOMY
Use a standard carpal tunnel approach with a mid-palm incision parallel to the thenar crease in line with the long finger.
Extend the incision proximally 4 cm in a zigzag fashion when crossing the wrist crease.
Protect the palmar cutaneous branch of the median nerve at the wrist flexion crease.
Divide the volar antebrachial fascia and protect the median nerve in the forearm.
Divide the palmar fascia and transverse carpal ligament longitudinally.
Excise hypertrophic synovium surrounding the flexor tendons (TECH FIG 2).
A complete synovectomy is not required when the excess synovium involves more than half of the tendon diameter. Synovectomy in this case would lead to loss in function.
Inspect the floor of the carpal tunnel. Any bony spicules (commonly originating from the scaphoid) are removed with a rongeur.
Check flexor tendons for decreased excursion, indicating digit tenosynovitis.2
TECH FIG 2 • Carpal tunnel approach to flexor tendons.
DIGITAL FLEXOR TENOSYNOVECTOMY
Use a volar zigzag incision to explore the flexor tendons in the digit.
Extend the incision proximally and distally for more exposure.
Excise all hypertrophic synovium (TECH FIG 3).
Carefully preserve the annular second and fourth pulleys to prevent bowstringing.
Excise nodules in the tendon and close defects with fine suture.
Check tendon excursion for smooth gliding.
Passive flexion of the finger should equal the flexion obtained when pulling on the tendon (simulating active flexion).
If passive and active flexion are not equal, additional synovectomy is required.2
TECH FIG 3 • Débridement of digit flexor tenosynovitis.
POSTOPERATIVE CARE
Splint the wrist in neutral position.
Early (within 48 hours) active and passive digit range of motion exercise is key to maintaining motion.1
OUTCOMES
Long-term studies show less than 10% tendon rupture and recurrent tenosynovitis at 5 years.
COMPLICATIONS
Wound dehiscence
Tendon adhesions
Tendon rupture1
REFERENCES
1. Brown FE, Brown ML. Long-term results after tenosynovectomy to treat the rheumatoid hand. J Hand Surg Am 1998;13:704–708.
2. Feldon P, Terrano A, Nalebuff E, et al: Rheumatoid arthritis and other connective tissue disease. In Green DP, Hotchkiss R, Pederson WC, eds. Green's Operative Hand Surgery, ed 5. New York: Churchill Livingstone, 2005:2060–2068.
3. Millender L, Nalebuff E, Albin R, et al. Dorsal tenosynovectomy and tendon transfer in the rheumatoid hand. J Bone Joint Surg Am 1974;56A:601–610.
4. Ryu J, Patel S. Rheumatoid arthritis: Soft tissue reconstruction. In: Trumble T, ed: Hand Surgery Update 3. Rosemont, IL: American Society for Surgery of the Hand, 2003:535–536.
5. Thirupathi R, Ferlic D, Clayton M. Dorsal wrist synovectomy in rheumatoid arthritis: A long-term study. J Hand Surg Am 1983;8:848–856.