Anbu Suresh Rao, C (2007) Assessment of the biomechanical properties of anterior cruciate ligament reconstruction using different techniques of fixation in a bovine knee model. Masters thesis, Christian Medical College, Vellore.
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Abstract
INTRODUCTION: Intra-articular reconstruction with a biologic tendon graft is the procedure of choice for restoring stability of a knee after rupture of the anterior cruciate ligament (ACL). Rigid fixation of the bone block in the tunnel is crucial for initial strength of the graft. Fixation with the help of an Interference screw is considered as the gold standard. Indirect fixation using polyester suture tied to a screw fixation post, and SS (Stainless Steel) wire tied to staples placed inferior to the bone tunnel outlet are other alternative techniques. This study was performed to evaluate the primary biomechanical parameters of three different fixation techniques – a) Staple fixation with SS wire, b) Polyester suture tied onto a screw fixation post, c) Interference screw. AIM: To evaluate the biomechanical properties of bone patellar tendon bone graft ( BPTB) fixation with different techniques in a bovine model. METHODS: Fifteen fresh bovine knees and bovine patellar tendons were used for the study. The BPTB graft was fixed to the tibia using the three different fixation techniques mentioned above. The patella was fixed to a load cell, and forces generated in the graft were recorded. In the first part of the study, the BPTB was pretensioned to an initial tension (or initial load) of 40N. The graft was then fixed using the three different methods, and the changes in tension (load) in the graft during fixation were recorded. The residual load in the graft after fixation was recorded and compared to the initial load (i.e. 40N in all instances). In the second part of this study, the graft was subjected to a single load-tofailure test, and the following parameters were recorded - ultimate failure load (the pullout strength), stiffness, and mode of failure. RESULT: Though the BPTB graft was fixed with an initial load of 40N, the graft tension at completion of fixation (residual load) with staple and SS wire, screw post with polyester suture and Interference screw was 94.00N, 72.80N, and 44.00 N respectively. In the single load-to-failure biomechanical testing, the ultimate failure load (pullout strength) and stiffness for Staple with SS wire was 726.40N and 61.9N respectively, for the Screw fixation post and polyester suture - 733.20N and 53.22N, and for Interference screw -594.00N and 79.50 N. There was no statistically significant difference in the stiffness and ultimate failure load using the three fixation techniques. In 4 specimens, the Staple with SS wire fixation failed when the SS wire cutting through the bone. In the fifth specimen, the SS wire untwisted during loading. With the screw fixation post, the polyester suture broke in all 5 specimens. With the interference screw, all failed by bone block pull out. CONCLUSION: There was a significant difference in the initial and residual load with use of staple fixation with SS wire and screw fixation post with polyester suture. When interference screw was used for fixation, initial load was similar to the residual load. The pullout strength of staple fixation with SS wire and screw fixation post with polyester suture was higher than when interference screw was used. Stiffness was higher with use of interference screw. However, the differences between three techniques was not statistically significant.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | biomechanical properties ; anterior cruciate ligament reconstruction ; fixation ; bovine knee model. |
| Subjects: | MEDICAL > Orthopaedics |
| Depositing User: | Subramani R |
| Date Deposited: | 21 Sep 2017 02:15 |
| Last Modified: | 21 Sep 2017 02:15 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/3031 |
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