title: Biomechanical and histological effects of intra-articular hyaluronic acid on anterior cruciate ligament in rats.
abstract: BACKGROUND
  The histologic and biomechanical effects of intra-articular hyaluronic acid on the anterior cruciate ligaments of rats were investigated.
  
  
  METHODS
  Thirty rats were divided into three groups, i.e., the hyaluronic acid group, saline group, and control group. The hyaluronic acid and saline groups received a total of four intra-articular injections, whereas no injection was administered to the control group. The hyaluronic acid group was injected with 50 microg (0.05 cc) hyaluronic acid, and the saline group was injected with 50 microl (0.05 cc) of 0.9% sodium chloride solution. All of the rats were sacrificed on day 29 and the femur-anterior cruciate ligament-tibia complexes from the right knees were prepared, tested mechanically, and evaluated histologically.
  
  
  RESULTS
  The mode of failure involved the midsubstance of the anterior cruciate ligament in all the specimens. There were no statistically significant differences in the stiffness and ultimate load to failure values between the three groups (P>0.05). The energy to failure values were evaluated and there was no statistically significant difference between the groups (P=0.064, chi-square=3.43). In the histologic analyses, there was a significant difference in the hyalinization values between the hyaluronic acid and saline groups (P=0.029) and between the hyaluronic acid group and control groups (P=0.029).
  
  
  CONCLUSIONS
  The present study shows that intra-articularly delivered hyaluronic acid has no statistically significant effect on the tensile strength of the rat anterior cruciate ligament. Although hyalinization was increased, no difference was found on the other markers for degenerative changes. We conclude that intra-articular hyaluronic acid injections can be performed safely, although the use of a precise injection technique is recommended.
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, University of Duzce, Duzce, Turkey. istemiyucel@yahoo.com
authors.forename: Istemi
authors.initials: I
authors.lastname: Yucel
authors.forename: Erkut
authors.initials: E
authors.lastname: Karaca
authors.forename: Kutay
authors.initials: K
authors.lastname: Ozturan
authors.forename: Umran
authors.initials: U
authors.lastname: Yildirim
authors.forename: Seckin
authors.initials: S
authors.lastname: Duman
authors.forename: Erdem
authors.initials: E
authors.lastname: Degirmenci
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000033:anatomy & histology* / Q000502:physiology*; D019245:Compressive Strength / Q000187:drug effects / Q000502:physiology; D055119:Elastic Modulus / Q000187:drug effects / Q000502:physiology; D006820:Hyaluronic Acid / Q000008:administration & dosage*; D007270:Injections, Intra-Articular; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013718:Tensile Strength / Q000187:drug effects / Q000502:physiology
chemical_list: D006820:Hyaluronic Acid