Comparison of Pull-out Strength for Different Bone Block Length in a Porcine Anterior Cruciate Ligament Model

Background: Bone and site hold tendon inside (BASHTI) is an implant-less technique that can solve some of the problems associated with other anterior cruciate ligament (ACL) reconstructive methods. This study aims to investigate the effect of core bone diameter variation on the biomechanical properties of a reconstructed ACL using BASHTI technique. Methods: A number of 15 laboratory samples of reconstructed ACL were built using bovine digital tendons and Sawbones blocks. Samples were divided into three groups with different core bone diameters of 8 mm, 8.5 mm, and 9 mm. The double-stranded tendon size and bone tunnel diameter were 8 mm and 10 mm, respectively. A loading scenario consisting of two cyclic loadings followed by a single cycle pull-out loading was applied to the samples simulating the after-surgery loading conditions to observe the fixation strength. Results: Results showed that the core bone diameter had a significant effect on the failure mode of the samples (P = 0.006) and their fixation strength (P < 0.001). Also, it was observed that the engaging length and the average cyclic stiffness (ACS) of them were influenced by the core bone diameter significantly (engaging length: P = 0.001, ACS: P = 0.007), but its effect on the average pull-out stiffness was not significant (P = 0.053). Conclusions: It was concluded that core bone diameter variation has a significant impact on the mechanical properties of ACL reconstruction when BASHTI technique is used, and it should be noted for surgeons who use BASHTI technique.

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Metal vs bioabsorbable interference screws: Initial fixation

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/095441103762597746 ◽

2003 ◽

Vol 217 (1) ◽

pp. 59-75 ◽

Cited By ~ 34

Author(s):

D J Beevers

Keyword(s):

Anterior Cruciate Ligament ◽

Cruciate Ligament ◽

Uniaxial Tensile ◽

Uniaxial Tensile Test ◽

Graft Material ◽

Interference Screws ◽

Pull Out ◽

Initial Fixation ◽

Anterior Cruciate ◽

Bioabsorbable Screws

Interference screws are used for graft fixation in anterior cruciate ligament reconstruction. There is current debate as to whether metal or bioabsorbable varieties provide the optimal results. This paper provides a critique of the single load-to-failure uniaxial tensile test data available in the literature, which provide the initial postoperative characteristics. Both metal and bioabsorbable screws were found to give similar levels of pull-out force and stiffness when used on similar types of graft material. Screws with bone-patellar tendon-bone grafts provided the greatest values, exceeding the forces transmitted through the native anterior cruciate ligament during normal daily activities. Hamstring grafts provided lower values, only being comparable with the forces of daily living. Consequently, this raises the question as to whether the rehabilitation regime of the hamstring patient must not be aggressive in the early postoperative stages when using either metal or bioabsorbable screws. This would ensure that the graft will not fail in the initial postoperative period before biological fixation occurs, which will then boost the strength to an acceptable level.

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