Article Text

Download PDFPDF
MRI and muscle enzymes do not support the diagnosis of local anesthetic myotoxicity: a descriptive case series


Background The presence of thigh muscle edema as characterized by increased signal intensity on MRI has been used to support the diagnosis of presumed local anesthetic-induced myotoxicity reported after total knee arthroplasty (TKA) with continuous adductor canal block (CACB). However, neither postoperative baseline imaging appearance nor muscle enzyme values have been described in conjunction with this clinical scenario. Thus, the usefulness of MRI or enzymatic biomarkers of muscle injury for supporting the diagnosis of local anesthetic myotoxicity is unknown.

Methods This descriptive case series documents postoperative MRI appearance of the ipsilateral upper leg, plus preoperative and postoperative creatine phosphokinase and aldolase values in volunteer patients who underwent uncomplicated TKA with CACB.

Results In 27 volunteer patients with no postsurgical evidence of clinically relevant myotoxicity, anterior thigh muscle edema was universally evident on imaging (n=12) and muscle enzyme values (n=19) were normal or only slightly elevated.

Conclusions The non-specificity of these findings suggests that MRI and near normal muscle enzyme levels are of limited diagnostic value when there is clinical suspicion of local anesthetic myotoxicity in the setting of TKA with CACB.

Trial registration number NCT04821245.

  • anesthesia
  • local
  • pain
  • postoperative
  • postoperative complications
  • lower extremity

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information. Deidentified raw data provided as supplementary information with this article.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.