The tibialis tendon as a valuable anterior cruciate ligament allograft substitute: biomechanical properties.

The study evaluates the biomechanical properties of single-strand and single-loop tibialis (anterior and posterior) tendon allografts. A comparison was made with bone-patellar tendon-bone (BPTB) allografts. Sixty-four tendon allografts were evaluated in this study. Sixteen of these were single-strand tibialis anterior (TA) and 16 single-strand tibialis posterior (TP) tendons. Sixteen single-loop TA and TP tendons were also tested. The fourth group was composed of 16 BPTB allografts. The biomechanical properties determined were maximal load, stiffness, cross-sectional area and elongation. The results of this study showed that the maximal load of the single-loop tibialis tendons (1,553 +/- 62 N) was greater than of the BPTB (1,139 +/- 99 N), TA (776 +/- 43 N) and TP (888 +/- 64 N) tendons. The stiffness of the single-loop tibialis tendons (236 +/- 10 N/mm) was also greater than of the BPTB (168 +/- 13 N/mm), TA (60 +/- 2 N/mm) and TP (73 +/- 5 N/mm) tendons. The cross-sectional area of the BPTB tendons was 67 +/- 5 mm(2), of the single-loop tibialis tendons 36 +/- 2 mm(2), of the TA tendons 20 +/- 1 mm(2), and of the TP tendons 23 +/- 1 mm(2). The elongation of the single-loop tibialis tendons and of the BPTB tendons was almost similar (7 +/- 0.4 mm). The same applied to the TA and TP tendons (14 +/- 0.6 mm). The results of this in vitro mechanical study suggest that fresh-frozen single-loop TA and TP tendons, and BPTB allografts are an acceptable substitute for hamstrings in anterior cruciate ligament reconstruction.