Quadrupled semitendinosus-gracilis autograft fixation in the femoral tunnel: a comparison between a metal and a bioabsorbable interference screw

Arthroscopy. 1998 Apr;14(3):241-5. doi: 10.1016/s0749-8063(98)70138-0.


Although semitendinosus-gracilis (SG) grafts for anterior cruciate ligament reconstruction have many potential benefits, effective fixation remains a challenge. This study assessed differences between the maximum pullout forces needed to detach a quadrupled SG graft from a femoral tunnel when secured by either a metal or a bioabsorbable interference screw. Sixteen paired fresh frozen quadrupled SG autografts (x, 8.4 mm; range, 7-10 mm) from 8 donors were anchored into cadaveric femoral tunnels by either a 7-mm metal or a 7-mm bioabsorbable screw after bone mineral density (BMD) assessment and before undergoing a longitudinal 20 mm/min traction force. Statistical analysis compared BMD (gm/cm2), insertional torque (N-m), and maximum load at pullout (N) between screw types. Insertional torques (.28-1.21, N-m range) did not correlate (P>.05) to BMD or maximum load at pullout (x +/- S.D.) 242 +/- 90.7 N (metal screw) and 341.1 +/- 162.9 N (bioabsorbable screw). Differences did not exist between the maximum load at pullout for bioabsorbable or metal screw fixation (P = .16). Careful graft preparation, sizing, and matched tunnel placement enables interference fit and fixation capable of reliably withstanding the low-level rehabilitation loads to which the graft is exposed until bony ingrowth occurs.

Publication types

  • Comparative Study

MeSH terms

  • Absorption
  • Aged
  • Anterior Cruciate Ligament / surgery*
  • Biomechanical Phenomena
  • Bone Density
  • Bone Screws*
  • Female
  • Femur / surgery*
  • Humans
  • In Vitro Techniques
  • Lactic Acid
  • Male
  • Middle Aged
  • Polyesters
  • Polymers
  • Tendons / transplantation*


  • Polyesters
  • Polymers
  • Lactic Acid
  • poly(lactide)