The aim of this study was to compare the initial fixation strength of tendon grafts between different sizes of bioabsorbable interference screws (BioScrew; Linvatec, Largo, FL) with bioabsorbable bead (EndoPearl; Linvatec) augmentation through biomechanical analysis of a porcine femoral bone model.
Forty pairs of porcine femurs and porcine flexor digitorum profundus tendons were divided into control and study groups. In the control group 8 × 30–mm BioScrews alone (n = 10) were inserted, whereas different sizes of BioScrews, measuring 7 × 30 mm (n = 10), 8 × 30 mm (n = 10), and 9 × 30 mm (n = 10), with 8–mm EndoPearl augmentation were inserted individually for fixation of tendon grafts in the study groups. All specimens were cyclically loaded with axial forces between 50 and 250 N at 1 Hz for 3,000 cycles and then incrementally loaded to failure at a rate of 150 mm/min.
BioScrews with EndoPearl augmentation had a significantly higher failure load than BioScrews alone (8–mm BioScrew alone v 8–mm BioScrew and EndoPearl, P < .05). There were no significant differences in the ultimate failure load (8 mm v 7 mm and 9 mm, P = .201 and P = .871, respectively), stiffness (8 mm v 7 mm and 9 mm, P = .789 and P = .823, respectively), displacement (8 mm v 7 mm and 9 mm, P = .695 and P = .781, respectively), and bone mineral density (P = .728 for all comparisons) except insertion torque (8 mm v 7 mm and 9 mm, P = .045 and P = .518, respectively) between study groups. Less tendon laceration by the screw thread was noted in the group in which smaller-sized BioScrews were used.
When EndoPearl augmentation was used, smaller-sized BioScrews (BioScrew size 1 mm smaller than bone tunnel) offered equivalent graft fixation strength to BioScrews of similar or larger sizes.
Smaller-sized BioScrews can be chosen if EndoPearl augmentation has been used, and EndoPearl augmentation may reduce the risk of tendon rupture while BioScrews are inserted.
To read this article in full you will need to make a payment
Purchase one-time access:Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
One-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:Subscribe to Arthroscopy
Already a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
- Biomechanical properties of quadruple tendon and patellar tendon femoral fixation techniques.Knee Surg Sports Traumatol Arthrosc. 2001; 9: 337-342
- Biomechanical analysis of femoral tunnel pull-out angles for anterior cruciate ligament reconstruction with bioabsorbable and metal interference screws.Am J Sports Med. 2007; 35: 637-642
- Interference screw fixation strength of a quadrupled hamstring tendon graft is directly related to bone mineral density and insertion torque.Am J Sports Med. 2000; 28: 705-710
- Graft laceration and pullout strength of soft-tissue anterior cruciate ligament reconstruction: In vitro study comparing titanium, poly-D, L-lactide, and poly-D, L-lactide-tricalcium phosphate screws.Arthroscopy. 2006; 22: 1204-1210
- Initial fixation strength of two bioabsorbable pins for the fixation of hamstring grafts compared to interference screw fixation.Am J Sports Med. 2004; 32: 641-649
- Primary stability of hamstring graft fixation with biodegradable suspension versus interference screws.Arthroscopy. 2005; 21: 266-274
- Initial and 6 weeks postoperative structural properties of soft tissue anterior cruciate ligament reconstructions with cross-pin or interference screw fixation: An in vivo study in sheep.Arthroscopy. 2007; 23: 14-20
- Observations on bone tunnel enlargement after double-bundle anterior cruciate ligament reconstruction.Arthroscopy. 2007; 23: 291-298
- The influence of screw geometry on hamstring tendon interference fit fixation.Am J Sports Med. 2000; 28: 356-359
- The EndoPearl device increases fixation strength and eliminates construct slippage of hamstring tendon grafts with interference screw fixation.Arthroscopy. 2001; 17: 353-359
- Augmentation of femoral fixation in hamstring anterior cruciate ligament reconstruction with a bioabsorbable bead.Am J Sports Med. 2004; 32: 159-163
- Anterior cruciate reconstruction using hamstring grafts fixed with BioScrews and augmented with the EndoPearl.Tech Orthop. 2005; 20: 264-271
- Anterior cruciate ligament reconstruction autograft choice: Bone-tendon-bone versus hamstring: Does it really matter?.Am J Sports Med. 2004; 32: 1986-1995
- Comparison of initial mechanical properties of 4 hamstring graft femoral fixation systems using nonpermanent hardware for anterior cruciate ligament reconstruction: An in vitro animal study.Arthroscopy. 2006; 22: 433-440
- Bone density and insertion torque as predictors of anterior cruciate ligament graft fixation strength.Am J Sports Med. 2004; 32: 1421-1429
- Hybrid femoral fixation of soft-tissue grafts in anterior cruciate ligament reconstruction using the EndoButton CL and bioabsorbable interference screws: A biomechanical study.Arthroscopy. 2006; 22: 1218-1224
Accepted: May 22, 2009
Received: March 25, 2008
The authors report no conflict of interest.
© 2009 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.