Electron microscopy of the remodelling process in hamstring tendon used as ACL graft

Knee Surg Sports Traumatol Arthrosc. 2010 Aug;18(8):1052-8. doi: 10.1007/s00167-009-0925-7. Epub 2009 Sep 29.


The purpose of the present study was to make a histological analysis of the remodelling process of hamstring tendon graft used as Anterior Cruciate Ligament (ACL). The hamstring graft of eight patients was biopsied at different follow-up times from 1 to 10 years. The specimens were analysed with transmission electron microscopy (TEM) at ultrastructural level comparing them with a native ACL and a native hamstring graft. The hamstring graft was found to undergo ultrastructural changes in terms of number and diameter of fibrils with the major changes occurring in the first 2 years. At longer times after surgery (48 and 120 months) no important further changes were evident and the ultrastructure did not vary substantially from 2 to 10 years. In conclusion, the hamstring tendon used as ACL graft undergoes a transformation process but does not match the ultrastructure pattern of a normal ACL up to 10 years.

MeSH terms

  • Adult
  • Anterior Cruciate Ligament / surgery*
  • Anterior Cruciate Ligament / ultrastructure
  • Anterior Cruciate Ligament Injuries
  • Arthroscopy
  • Biopsy
  • Case-Control Studies
  • Collagen / ultrastructure
  • Follow-Up Studies
  • Humans
  • Male
  • Microscopy, Electron, Transmission
  • Tendons / transplantation*
  • Tendons / ultrastructure*


  • Collagen