Adductor Canal Blocks May Result in Long-Term Neuropathy After Total Knee Arthroplasty

Background The aims of this study were to determine the incidence of block-related complications after adductor canal blocks (ACB) in total knee arthroplasty (TKA), identify associated risk factors, and investigate if there were any differences in clinical outcomes. Methods 368 consecutive patients underwent primary TKA from January 2017 to December 2019, of which 207 had an ACB. Patient demography, comorbidities, intraoperative details, complications, and clinical outcomes were retrospectively reviewed. The relationship between these variables and block-related complications was investigated. Results At 6 weeks after surgery, 8.7% of patients who received an ACB reported symptoms over the saphenous nerve distribution while 6.3% and 4.8% had persistent symptoms at 1 year and 5 years respectively. 55.6% of these patients were treated for neuropathic pain in the early postoperative period. Significant association was found between neuropathy after an ACB and the presence of spine pathology, use of dexmedetomidine, administration of spinal anaesthesia (SA)-only and volume of local anaesthetic. Multivariate logistic regression analysis identified spine pathology and the administration of SA-only as significant contributors to the presence of neuropathy after an ACB. There were differences in early clinical outcomes between groups but not at 6 months and 1 year postoperatively. Conclusion Adductor canal blocks may result in persistent neuropathy and problematic symptoms after total knee arthroplasty.