Effect of Geometry on the Fixation Strength of Anterior Cruciate Ligament Reconstruction Using BASHTI Technique

Abstract

The goal of this study is to investigate the effects of tendon and cannulated drill bit diameter on the strength of the bone and site hold tendon inside (BASHTI) fixation technique for an anterior cruciate ligament (ACL) reconstruction. Bovine digital tendons and Sawbones blocks were used to mimic the ACL reconstruction. Mechanical strength of the specimens was measured using a cyclic loading continued by a single cycle pullout load until failure to simulate the real postsurgical loading conditions. Finally, failure modes of specimens and ultimate failure load were recorded. The maximum possible tendon surface strain (i.e., tendon compression [TC]) for tendon diameters of 6, 7, 8, and 9 mm were 0.73, 0.8, 0.7, and 0.65, respectively. Eighty per cent of the specimens with tendon diameter of 6 mm and 20% of specimens with tendon diameter of 7 mm failed on the torn tendon. All samples with larger tendon diameters (i.e., 8 and 9 mm) failed on the fixation slippage. The maximum fixation strength according to the most suitable core bones for 6, 7, 8, and 9 mm tendons were 148 ± 47 N (core 9.5 mm), 258 ± 66 N (core 9.5 mm), 386 ± 128 N (core 8.5 mm), and 348 ± 146 N (core 8.5 mm), respectively. The mode of tendon failure was significantly influenced by the tendon diameter. Also, an increase in TC raised the fixation strength for all tendon diameters; however, tendon over compression decreased the fixation strength for the 8 mm tendon group. Finally, an empirical equation was proposed to predict BASHTI fixation strength.

Core bone diameter in an organic implant-less technique affecting the biomechanical properties of the anterior cruciate ligament fixation; an in-vitro study

“…So, some specimens failed in the cyclic loading step. It is in agreement with the results of previous studies on this method 14 . Also, it was observed that the core bone diameter had a significant effect on the maximum strength of the reconstructed ACL (P-value = 0.000).…”

“…So, some specimens failed in the cyclic loading step. It is in agreement with the results of previous studies on this method 14 .…”

“…The tunnel diameter and double-stranded tendon size were considered to be 10 mm and 8 mm, respectively. These values proved to have the best mechanical properties for BASHTI technique in previous studies 14 .…”

“…The tendons were kept moist by spraying water during preparation and testing procedures maintain their mechanical properties 18 . Moreover, Sawbones Polyurethane blocks (1522-03, Sawbones Europe AB, Malmo, Sweden) with a density of 320 Kg/m 3 (20 lb/ft 3 ) were used as the artificial bone to represent young human tibia bone 14,19 (Fig. 1 c).…”

“…Recently, it was observed that this parameter significantly affects the strength of BASHTI fixation with an experimental study using bovine digital tendons and artificial bones. It was showed that increasing the tendon compression up to an optimum value could improve the fixation strength 14 .…”