Question: For patients with trigger thumb, is percutaneous release
with steroid injection (PRSI) better than steroid injection (SI) alone for
relieving symptoms?
Design: Randomized (unclear allocation concealment), unblinded,
controlled trial with 2-week and 6-month follow-up.
Setting: Bangkok, Thailand.
Patients: 115 adult patients who had idiopathic trigger thumb
(Quinnell grade 2, 3, or 4) and did not have a history of carpal tunnel
syndrome or trauma. Follow-up was 98% (mean age, 52 yr; 93% women).
Intervention: 127 thumbs in 115 patients were allocated to either
PRSI (66 thumbs in 60 patients) or SI alone (61 thumbs in 55 patients). One
patient from each group was lost to follow-up and was excluded, leaving 125
thumbs in 113 patients (65 thumbs in 59 patients in the PRSI group, and 60
thumbs in 54 patients in the SI-alone group) for analysis. In the PRSI group,
the point of triggering at the A1 pulley of the metacarpophalangeal joint was
located. After disinfecting the skin, 2.5 mL of 1% lidocaine hydrochloride
(without adrenaline) was injected into the subcutaneous tissue and the flexor
tendon. An 18-gauge needle was inserted at 1 to 2 mm distal to the
metacarpophalangeal joint crease, with the thumb hyperextended. The needle was
withdrawn slightly so that its tip lay in the A1 pulley, and its bevel was
moved longitudinally from proximal to distal to cut the A1 pulley until the
grating sensation stopped. Patients were asked to flex and extend the thumb to
confirm that it no longer triggered. The flexor tendon sheath within the
metacarpophalangeal flexion crease was then injected with 1 mL of
triamcinolone acetonide (10 mg/mL), with use of a 25-gauge needle. In the
SI-alone group, the flexor sheath was injected with 1 mL of triamcinolone
acetonide and 1 mL of
lidocaine.
Main outcome measures: Satisfactory response (pain score on visual
analog scale [0 (none) to 10 (severe)] of 1 or less and triggering grade
0).
Main results: More thumbs in the PRSI group than in the SI-alone
group (after 1 injection) were associated with a satisfactory response
(Table). After 6 patients in the SI-alone group had 2 injections and 4
patients had 3 injections, the difference in satisfactory response remained
the same (Table). Cellulitis occurred in 1 patient after the second steroid
injection. No digital nerve injury occurred in either group.
Conclusions: For patients with trigger thumb, percutaneous release
with steroid injection was better than steroid injection alone for reducing
pain and trigger thumb.
The authors of this study evaluated 113 patients with trigger thumb to test
their hypothesis that percutaneous release of the A1 pulley, when combined
with local injection of corticosteroid and local anesthetic, is superior to
injection of corticosteroid and local anesthetic alone. Although the authors'
results are significant (p = 0.001), percutaneous release of a trigger thumb
in the office setting is not a widely performed procedure.
The substantial amount of local anesthetic (2.5 mL of 1% lidocaine) that
was injected into the surgical field could possibly distort the local anatomy
and displace the radial digital nerve of the thumb. Since the subcutaneous
position of this nerve puts it at risk for injury in its normal location,
nerve displacement might prove disastrous. In this clinical setting, injury to
the radial digital nerve would not be appreciated until hours later.
How might this complication be avoided? The radial digital nerve, which
lies 2.19 mm beneath the
skin1 immediately
radial and adjacent to the fibrous flexor sheath and the A1 pulley, can be
palpated fairly readily in most individuals. Palpation of this nerve followed
by marking its location with indelible ink prior to surgical intervention
might lessen the possibility of either temporary or permanent nerve
injury.
The routine, nonoperative treatment of trigger thumb consists of oral
nonsteroidal anti-inflammatory agents, percutaneous injection of
corticosteroids, and the occasional use of a splint to keep the
interphalangeal joint of the thumb in extension. Should these nonoperative
modalities not lead to resolution of symptoms, an open release is performed.
For most surgeons, an open release of the A1 pulley is a safe, quick, and
straightforward procedure as long as the anatomy of the radial digital nerve
of the thumb is appreciated. Percutaneous release adds an unnecessary layer of
risk and complexity to a treatment that is straightforward and has withstood
the test of time.
Carrozzella J, Stern PJ, Von Kuster
LC. Transection of radial digital nerve of the thumb during trigger
release. J Hand Surg [Am].1989;14:2 Pt 1:
198-200.14198
1989
[PubMed][CrossRef]