Subacromial Local Anesthetics Do Not Interfere With Rotator Cuff Healing After Arthroscopic Repair

Abstract

Background: Subacromial pain pumps are used for analgesia after arthroscopic rotator cuff surgery. However, there is controversy about myotoxic or tendinotoxic effects of local anesthetics. Hypothesis: Ropivacaine administered via a subacromial pain pump would have no adverse effect on rotator cuff tendon healing, fatty degeneration, strength, or functional outcomes after arthroscopic repair. Study Design: Cohort study; Level of evidence, 3. Methods: This study continues follow-up of patients enrolled in the authors’ 3 published prospective studies regarding pain control after arthroscopic rotator cuff repair. In total, 118 patients who underwent rotator cuff repair and returned for evaluation at least 1 year postoperatively were divided into 3 groups: patients who received continuous subacromial ropivacaine infusion (group 1, n = 33), those who received patient-controlled subacromial ropivacaine infusion (group 2, n = 30), and those who received other pain control modalities (intravenous patient-controlled analgesia and/or interscalene block; group 3, n = 55). At least 1 year postoperatively, tendon healing and changes in global fatty degeneration index (GFDI) were estimated through computed tomographic arthrography, magnetic resonance imaging, or ultrasonography. Changes in isokinetic muscle performance test (IMPT) were calculated and functional outcomes evaluated, including visual analog scales (VASs) for pain and satisfaction, American Shoulder and Elbow Surgeons score, and Constant score. Results: At final follow-up, there were no differences in pain VAS (group 1, 1.1 ± 2.3; group 2, 1.3 ± 1.9; group 3, 0.9 ± 1.7; P = .88), satisfaction VAS (group 1, 8.3 ± 2.4; group 2, 8.7 ± 1.5; group 3, 8.0 ± 2.1; P = .64), American Shoulder and Elbow Surgeons score (group 1, 79.5 ± 10.5; group 2, 81.1 ± 6.9; group 3, 75.7 ± 7.6; P = .34), or Constant score (group 1, 81.8 ± 8.7; group 2, 77.6 ± 9.3; group 3, 78.2 ± 8.4; P = .31). Among the 3 groups, there were no significant differences in healing rates (group 1, 72.7%; group 2, 73.3%; group 3, 70.9%; P = .83) and no differences in changes of GFDI (group 1, 0.45; group 2, 0.62; group 3, 0.41; P = .79), and IMPT (abduction: group 1, 113.0%; group 2, 121.5%; group 3, 120.1%; P = .73; external rotation: group 1, 112.1%; group 2, 121.6%; group 3, 111.7%; P = .71; internal rotation: group 1, 118.2%; group 2, 118.0%; group 3, 118.1%; P = .95). When data were reanalyzed with 2 groups (group 1 + 2 vs group 3), there were no significant differences in functional scores, healing rates, or changes in GFDI and IMPT (P > .05). Conclusion: Current data suggest that myotoxicity of subacromial ropivacaine administered via pain pump may be reversible or may not be so severe as to interfere with tendon healing and cause muscle degeneration and thus may not affect postoperative function.