Pulsed electromagnetic field therapy improves tendon-to-bone healing in a rat rotator cuff repair model.
Rotator cuff tears are common musculoskeletal injuries often requiring surgical intervention with high failure rates. Currently, pulsed electromagnetic fields (PEMFs) are used for treatment of long-bone fracture and lumbar and cervical spine fusion surgery. Clinical studies examining the effects of PEMF on soft tissue healing show promising results. Therefore, we investigated the role of PEMF on rotator cuff healing using a rat rotator cuff repair model. We hypothesized that PEMF exposure following rotator cuff repair would improve tendon mechanical properties, tissue morphology, and alter in vivo joint function. Seventy adult male Sprague-Dawley rats were assigned to three groups: bilateral repair with PEMF (n = 30), bilateral repair followed by cage activity (n = 30), and uninjured control with cage activity (n = 10). Rats in the surgical groups were sacrificed at 4, 8, and 16 weeks. Control group was sacrificed at 8 weeks. Passive joint mechanics and gait analysis were assessed over time. Biomechanical analysis and μCT was performed on left shoulders; histological analysis on right shoulders. Results indicate no differences in passive joint mechanics and ambulation. At 4 weeks the PEMF group had decreased cross-sectional area and increased modulus and maximum stress. At 8 weeks the PEMF group had increased modulus and more rounded cells in the midsubstance. At 16 weeks the PEMF group had improved bone quality. Therefore, results indicate that PEMF improves early tendon healing and does not alter joint function in a rat rotator cuff repair model. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:902-909, 2017.
McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104-6081.
Jennica J
JJ
Tucker
McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104-6081.
James M
JM
Cirone
McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104-6081.
Tyler R
TR
Morris
McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104-6081.
Courtney A
CA
Nuss
McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104-6081.
Julianne
J
Huegel
Department of Research and Clinical Affairs, Orthofix Inc., Lewisville, Texas.
Erik I
EI
Waldorff
Department of Research and Clinical Affairs, Orthofix Inc., Lewisville, Texas.
Nianli
N
Zhang
Department of Research and Clinical Affairs, Orthofix Inc., Lewisville, Texas.
James T
JT
Ryaby
McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, Pennsylvania, 19104-6081.
Louis J
LJ
Soslowsky
D000818:Animals; D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000473:pathology*; D003430:Cross-Sectional Studies; D004574:Electromagnetic Fields; D007596:Joints / Q000473:pathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017006:Rotator Cuff / Q000473:pathology*; D000070636:Rotator Cuff Injuries / Q000628:therapy*; D013314:Stress, Mechanical; D013708:Tendon Injuries / Q000503:physiopathology; D013710:Tendons / Q000473:pathology*; D014945:Wound Healing; D055114:X-Ray Microtomography
PEMF; animal model; supraspinatus repair