Safety of corticosteroid injection for carpal tunnel syndrome

The risks of corticosteroid injection for carpal tunnel syndrome, principally intraneural injection and tendon rupture, are known only from anecdotal reports. The literature does not allow an accurate estimate of their incidence or that of lesser side effects such as local pain. We have encountered only four serious complications in 9515 injections. We asked patients about possible side effects at routine follow-up, 6 weeks after 689 injections with 40mg triamcinolone. Possible side effects were reported after 33% of injections. The commonest was short-lived local pain, which occurred in 13% of injected limbs, all cases having resolved within 3 weeks. No cases of intraneural injection or tendon rupture occurred, even after repeated injection. Most adverse effects were transient, but 13 hands exhibited persistent skin depigmentation or subcutaneous atrophy. This data provides the best current estimate of the risks of carpal tunnel injection and may be used to inform patients considering this intervention. Level of evidence: IV