Effectiveness of Ultrasound-Guided Canal Adductor Blockade for Chronic Pain and Functioning in Knee Osteoarthritis: A Prospective Longitudinal Observational Study.

METHODS

Seventy-seven patients with chronic knee osteoarthritis pain received ultrasound-guided ACB with 14 ml 0.25% levobupivacaine and 100 mcg clonidine. At baseline and 1 month after the blockade, we assessed maximal and minimal pain intensity in the knee using a numeric rating scale (NRS) and the Knee Injury and Osteoarthritis Outcome Score (KOOS). The range of motion in extension and flexion (ROMext and ROMflex) and quadriceps muscle strength of both knees (QS), Timed Up and Go Test (TUG), and 30-Second Chair Stand Test (30CST) results were determined at baseline, 1 hour, 1 week, and 1 month after the blockade.

RESULTS

ACB with levobupivacaine and clonidine appeared to decrease pain severity (NRS 8.13 to 4.2, < 0.001 and NRS 3.32 to 1.40, < 0.001). Similarly, knee ROMext decreased from 3.90 preintervention to 2.89 postintervention at 1 month, < 0.001; ROMflex decreased from 5.70 to 3.29, < 0.001; TUG time decreased from 3.22 to 2.93, <0.001; QS increased from 18.43 to 22.77, < 0.001; CST increased from 8.23 to 10.74, < 0.001. The KOOS for pain (36.40 to 58.34), symptoms (52.55 to 64.32), activities of daily living functions (ADLs, 36.36 to 60.77), and quality of life (QoL, 17.87 to 30.97) also increased, all < 0.001.

CONCLUSION

ACB appeared to decrease pain and increase ambulation. If our preliminary results are reproducible in a planned randomized controlled trial, ACB could be a useful adjunctive pain therapy in patients with disabling pain due to knee OA.