BACKGROUND: We performed a randomized, blinded pilot study in 12 volunteers to assess the feasibility to reposition an intentionally displaced suture-method catheter for two different insertion techniques for adductor canal block.

METHODS: Each volunteer had an ultrasound-guided suture-method catheter placed in the adductor canal (AC) in both legs. The catheters were placed using a perpendicular technique in one leg and a parallel technique in the other leg, according to randomization. 15 mL lidocaine 1% (LA) was injected in each catheter. Successful primary placement was defined as combined LA spread within the AC and loss of cold sensation 15 min after injection. All catheters were intentionally displaced, and subsequently repositioned using ultrasound. Another dose of lidocaine (15 mL 1%) was injected through the catheters and assessed for successful repositioning.

RESULTS: Successful primary placement was achieved in 83% (95% CI 55-95%) of catheters placed perpendicular to the AC, and in 75% (95% CI 47-91%) of catheters placed parallel to the AC. Of those with successful primary placement, 100% (95% CI 72-100%) of catheters placed perpendicular to the AC, and 67% (95% CI 35-88%)) placed parallel to the AC could be repositioned.

CONCLUSIONS: Placement and secondary repositioning after displacement of a suture-method catheter within the adductor canal is achievable. A perpendicular technique seems more reliable.

TRIAL REGISTRATION: NCT03315481 clinicaltrials.gov . The study was submitted on March 1, 2017. Due to clerical error, the study was posted on October 20, 2017.