gms | German Medical Science

Joint German Congress of Orthopaedics and Trauma Surgery

02. - 06.10.2006, Berlin

Tibial press fit fixation of the hamstring tendons for ACL-reconstruction

Meeting Abstract

  • M. Jagodzinski - Unfallchirurgische Klinik, Medizinische Hochschule Hannover (MHH), Hannover, Germany
  • K. Scheunemann - Unfallchirurgische Klinik, Medizinische Hochschule Hannover (MHH), Hannover, Germany
  • K. Knobloch - Unfallchirurgische Klinik, Medizinische Hochschule Hannover (MHH), Hannover, Germany
  • C. Krettek - Unfallchirurgische Klinik, Medizinische Hochschule Hannover (MHH), Hannover, Germany
  • C. Hurschler - Labor für Biomechanik und Experimentelle Orthopädie, Medizinische Hochschule Hannover (MHH), Hannover, Germany
  • J. Zeichen - Unfallchirurgische Klinik, Medizinische Hochschule Hannover (MHH), Hannover, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie. 70. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 92. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie und 47. Tagung des Berufsverbandes der Fachärzte für Orthopädie. Berlin, 02.-06.10.2006. Düsseldorf, Köln: German Medical Science; 2006. DocW.4.1.5-1157

The electronic version of this article is the complete one and can be found online at:

Published: September 28, 2006

© 2006 Jagodzinski et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Purpose: The purpose of this study was thus to develop and mechanically characterize a tibial press fit technique using the hamstrings tendons that does not rely on hardware or interference screw fixation.

Methods: 21 hamstring tendons were explanted from the knees of 15 human cadavers for use in this study. A bone block was harvested from the tibia medial of the tibial tuberosity (30x9mm). Thirty fully grown German landrace pigs were used as a model for the tibial drill holes. Interference screw fixation (I; Sysorb®, Centerpulse Medical AG, Winterthur, Switzerland) was compared with press-fit tape fixation (T; Mersilene, Ethicon Inc., Somerville, New Jersey) and suture fixation (S). In both groups T and S, a cortical bone block was introduced into the medial side of the tibial tunnel and advanced with a pusher until it came to rest at the proximal tunnel outlet. The bone tunnel-force direction angle was 0°. The constructs were pre-tensioned with 50N for 30s prior to testing. Subsequently, 1500 cycles of sinusoidal loading ranging from 50N and 200N were applied at a repetition rate of 0.5Hz. The increase in construct length was recorded during cyclical loading. Length changes were reported between first and 5th, 5th and 20th, 20th and 50th, and 50th to 1500th cycle. After cyclical loading, loading of the specimens was ramped down to 10N for 30s after which the constructs were tested to failure at an actuator speed of 1mm/s.

Results: Maximum pull out forces observed were 970±83N (range: 853-1087N) for the T-fixation, 402±78N (303-485N) for the S-fixation, and 544±109N (440-756N) for the I-fixation, with all groups being significantly different from another (ANOVA, p<0.001). The stiffness of T-fixation group was lower (78±13N/mm; range: 59-95N/mm) than the S-fixation group (108±18N/mm; 88-145N/mm). The interference screw fixation demonstrated the highest stiffness (162±27N/mm; 129-207N/mm), again with all differences being significant (p<0.03). Cyclical loading elongation between the 1st and 5th loading cycle was 2.0±0.6mm (range: 1.5-3.1mm) for T-fixation, 3.3±1.1mm (2.1-5.4mm) for S-fixation, and 1.4±0.5mm (0.4-2.6mm) for I-fixation constructs. Cyclical loading elongation of S fixation was significantly larger than the other observed techniques (p<0.05). From the 5th to the 20th loading cycle, length changes were significantly less than over the first five cycles in all groups, being reduced to 0.15±0.04mm (0.08-0.2mm) for T-fixation, 0.33±0.06mm (0.27-0.42mm) for S-fixation, and 0.14±0.06mm (0.06-0.2mm) for the I-fixation constructs. Elongation of the S-fixation group was still larger than the other groups (p<0.01). Between the 20th and 1500th cycle, elongation for T-fixation (2.2±0.07mm (1.4-3.5mm)) was significantly less than for the other constructs (p<0.001, S-fixation 4.8±0.7mm, range 3.7-5.8mm; I-fixation 4.1±2.7mm, range 2.0-9.9mm).

Conclusion: The results of this study suggest that the implant free T-fixation technique provides comparable mechanical properties to interference screw fixation. Further studies of the healing process of this fixation technique are necessary before clinical application could be considered. These studies must include a careful analysis of bone tunnel enlargement.

Figure 1 [Fig. 1]