The most common variations of tenovaginitis (tendon sheath inflammation) in our Caribbean hand surgery clinic at Trinidad Institute of Plastic Surgery are trigger finger and de Quervain’s disease. They share the feature of compression of the affected tendon in a rigid tunnel. In the case of trigger finger or trigger thumb compression occurs at the entrance of the flexor sheath of the finger, the so called A1 pulley. De Quervain’s disease is characterized by narrowing of the first dorsal extensor compartment at the level of the wrist and compression of the abductor pollicis longus and extensor pollicis brevis. The symptoms of tenovaginits are tethering with painful motion, locking, swelling and occasionally crepitus.
There appears to be an innate tendency to develop this disease in association with carpal tunnel syndrome and arthritis of the first carpometacarpal joint – the “unhappy triad”, a term I owe to my teacher Dr. Belsole. An additional association exists with epicondylitis lateralis (“tennis elbow”) and subacromial bursitis. The diathesis and its manifestations are by far more common in women than in men.
Trigger finger and de Quervain’s disease are diseases of the tendon sheath. Histologic studies consistently demonstrate lack of inflammatory changes within the tendon itself and the tenosynovium, whereas fibrotic thickening, vascular proliferation and cartilaginous metaplasia are demonstrable in the retinacular sheath.
The association with occupational factors and trauma is not unambiguous. On the one hand the incidence is strikingly low in males, who more often have occupations requiring heavy manual labor and the age distribution with peak in the fifth to sixth decades has not appreciably changed despite the use of computer keyboards and other “repetitive” tasks.
Trigger digits are caused by a disproportion in size between the flexor tendons and their retinacular pulley at the level of the metacarpal head (A1 pulley). Flexion of the proximal phalanx at the metacarpophalangeal joint, particularly with power grip, causes high angular loads at the distal edge of the A1 pulley. Remodelling takes place at this edge leading to hypertrophy, fibrocartilaginous metaplasia and narrowing. Changes in the tendon itself are reactive and not causative and are not addressed in current treatment strategies.
Fritz de Quervain described stenosing tendovaginitis involving the sheaths of the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) at the radial styloid as a cause of wrist and hand pain. Activities requiring abduction of the thumb with simultaneous ulnar deviation of the wrist again increase the angular load at the proximal aspect of the extensor retinaculum inciting hypertrophy, inflammation and fibrocartilaginous metaplasia.
Both entities merit a trial of conservative therapy with antiinflammatories, activity modification, occasionally splinting (more successful in thumb) and steroid injection into the tendon sheath.
Failure of conservative treatment is not infrequent and represents an indication for surgery.
Trigger fingers are treated by vertical division of the A1 pulley under direct vision through a small incision in the palm. Release of the A1 pulley of the thumb is done through a small transverse excision in the proximal flexion crease. A somewhat larger transverse, J or W shaped incision proximal to the radial styloid gives access to the first dorsal compartment. Here anatomic variations may be possible and it is essential to release all subcompartments including the one for the extensor pollicis brevis.
In either case the main risk of the procedure is damage to sensory nerves. digital nerves may be injured during trigger finger release, the radial digital nerve of the thumb is at risk during trigger thumb release and branches of the dorsal sensory branch of the radial nerve overlie the first dorsal compartment in the immediate subcutaneous plane.
In our Caribbean hand surgery clinic at Trinidad Institute of Plastic Surgery we perform these procedures on an outpatient basis under regional or general anesthesia and torniquet control. A light dressing is applied. Immobilization of the affected digits or wrist is not considered necessary. Sutures may be removed in seven to ten days. Use of the hand for activities of daily living is permitted immediately. Return to manual labor is recommended once scars are stable, but is often dependent on patient motivation.
Trigger thumb, but very rarely tirgger finger, may occur as a congenital entity. In this instance, conservative treatment is uniformly unsuccessful and only used to maintain motion until decompression can be safely performed, usually prior to the child reaching one year of age, when increasing integration of the thumb into the prehensile patterns of hand use occurs.
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