Combined ultrasound, electrical stimulation, and laser promote collagen synthesis with moderate changes in tendon biomechanics

Steven L. Gum, G. Kesava Reddy, Lisa Stehno-Bittel, Chukuka S. Enwemeka

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)


The biomechanical, biochemical, and ultrastructural effects of a multitherapeutic protocol were studied using regenerating rabbit Achilles tendons. The multitherapeutic protocol was composed of low-intensity Ga:As laser photostimulation, low intensity ultrasound, and electrical stimulation. Achilles tendons of 63 male New Zealand rabbits were tenotomized, sutured, immobilized, and subjected to the multitherapeutic protocol for five days, after which casts were removed and the therapy was continued for nine more days without electrical stimulation. The tendons were excised and compared with control tendons. Multitherapy treatment produced a 14% increase in maximal strength, a 42% increase in load-at-break, a 20% increase in maximal stress, a 45% increase in stress-at-break, a 21% increase in maximal strain, and a 14% increase in strain-at-break. Similarly, multitherapy treatment was associated with an increase in Young's modulus of elasticity of 31%, an increase in energy absorption at maximum load of 9%, and an increase in energy absorption at load-at-break of 11%. Biochemical analysis of the tendons showed an increase of 23% in the total amount of collagen in the multitherapy-treated tendons, with fewer mature crosslinks (decrease of 6%). Electron micrographs revealed no ultrastructural or morphologic changes in the tendon fibroblasts or in the extracellular matrix. The improvements measured in tendons receiving multitherapy were consistent but less remarkable compared with our earlier works with single modality protocols. The results warrant the hypothesis that the beneficial effects of ultrasound and laser photostimulation on tendon healing may counteract one another when applied simultaneously.

Original languageEnglish
Pages (from-to)288-296
Number of pages9
JournalAmerican Journal of Physical Medicine and Rehabilitation
Issue number4
Publication statusPublished - Jul 1997
Externally publishedYes


  • Collagen Synthesis
  • Electrical Stimulation
  • Laser Therapy
  • Tendon Healing
  • Therapeutic Ultrasound

ASJC Scopus subject areas

  • General Medicine


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