Effect of hylan G-F 20 in Achilles' tendonitis: an experimental study in rats

Arch Phys Med Rehabil. 2004 Sep;85(9):1470-4. doi: 10.1016/j.apmr.2003.09.022.


Objective: To investigate the local effects of hylan G-F 20 on locally administered corticosteroid-induced experimental Achilles' tendonitis.

Design: Before-after trial.

Setting: Institutional practice.

Animals: Convenience sample of 18 male Wistar white rats (weight range, 322-375 g).

Interventions: After performing Achilles' degeneration with local corticosteroid injections, the rats were divided into 4 groups. The right Achilles' tendon of the rats served as the hylan injection group and the left tendon as the control group, which was injected with saline at 5-day intervals. The tendons and paratenons were excised at the end of 60 or 75 days and evaluated histopathologically and statistically.

Main outcome measure: Histopathologic changes, including staining affinity, nuclear appearance, fibrillar appearance for tendon and thickness, occurrence of fibrosis and edema, capillary changes, and inflammation for paratenon, were assessed according to a semiquantitative scoring system. The Mann-Whitney U test was used for statistical analysis, with a P value of.05 or less considered statistically significant.

Results: Semiquantitative scoring of histopathologic changes showed that histologic appearances differed between the hylan and saline groups and between 2 hylan groups. Hylan-injected tendons and paratenons demonstrated significantly lower scores, especially after 75 days.

Conclusions: Hylan G-F 20 has a promising curative effect on the tendon and paratenon and can be used in Achilles' tendonitis. This finding should be supported by biomechanical and biochemical studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Achilles Tendon* / pathology
  • Animals
  • Betamethasone / analogs & derivatives*
  • Chronic Disease
  • Disease Models, Animal*
  • Drug Administration Schedule
  • Drug Combinations
  • Drug Evaluation, Preclinical
  • Edema / etiology
  • Fibrosis
  • Hyaluronic Acid / analogs & derivatives*
  • Hyaluronic Acid / chemistry
  • Hyaluronic Acid / pharmacology
  • Hyaluronic Acid / therapeutic use*
  • Injections
  • Male
  • Rats
  • Rats, Wistar
  • Severity of Illness Index
  • Single-Blind Method
  • Sodium Chloride / therapeutic use
  • Statistics, Nonparametric
  • Tendinopathy / chemically induced
  • Tendinopathy / complications
  • Tendinopathy / drug therapy*
  • Tendinopathy / pathology


  • Drug Combinations
  • betamethasone dipropionate, betamethasone sodium phosphate drug combination
  • hylan
  • Sodium Chloride
  • Hyaluronic Acid
  • Betamethasone