Out-of-sheath corticosteroid injections through the dorsal webspace for trigger finger and trigger thumb. A prospective cohort study

BACKGROUND AND OBJECTIVE

Steroid injections are effective in the treatment of trigger digits but the pain during the injection is an always-present accompanying effect. The aim of this study was to assess the effectiveness and perceived pain during an out-of-sheath corticosteroid injection through the dorsal webspace in the treatment of trigger digits.

MATERIAL AND METHOD

A total of 126 consecutive patients were included. A subcutaneous (out-of-sheath) corticosteroid injection was performed through the dorsal webspace in all digits. In cases where signs or symptoms persisted, a second injection was offered. Visual analog scale for pain during the injection, DASH questionnaire, success rate and complications were collected.

RESULTS

There were 86 women and 40 men with a mean age of 61 years. The mean visual analog scale for pain during the injection was 3.8. Twelve patients were lost to follow-up. The overall success was 68% and success after a single injection was 54%. The best result was achieved on the ring finger. Patients who were not previously operated on carpal tunnel syndrome responded better. No complications were noted.

CONCLUSIONS

The extra-sheath corticosteroid injection through the dorsal webspace is effective and safe. It seems to be less painful than the reported scores for the palmar midline technique although it should be assessed in a comparative study.

Dorsal web injection technique in the treatment of trigger finger and trigger thumb. Anatomical study

BACKGROUND AND OBJECTIVE

Corticosteroid injection is an effective treatment for trigger digits but the pain during the injection is an ever-present side effect. Since the palmar skin has a high density of sensitive receptors, injecting through dorsal skin could be less painful. Our aim was to assess whether a dorsal technique through the dorsal web is safe for extra-sheath injection of trigger fingers and thumb.

MATERIAL AND METHOD

This is an anatomical study in sixteen cadaveric hands. An injection through the dorsal web was performed on each digit. After careful resection of the palmar skin, the distance between the needle and the main anatomical structures was measured. The risk of major injury was considered high when the mean distance from the needle to the neurovascular bundle was below 1mm.

RESULTS

The mean distance from the needle to the neurovascular bundle was 1.77mm. Two neurovascular injuries in 112 injections were observed, one nerve and one artery. The safest digit was the thumb while the most dangerous was the index finger. At the ring finger, the technique was safer when it was carried out from the dorso-radial.

CONCLUSIONS

A subcutaneous injection near the flexor tendon sheath can be carried out through the dorsal web with a low, but present, risk of neurovascular injury. It could be useful for injection in the treatment of trigger finger and trigger thumb but it should be assessed in a clinical study.