Cyclic Loading Comparison Between Biodegradable Interference Screw Fixation and Biodegradable Double Cross-Pin Fixation of Human Bone-Patellar Tendon-Bone Grafts (original) (raw)
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Primary stability of bone-patellar tendon-bone graft fixation with biodegradable pins
Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2003
We evaluated the initial bone-patellar tendon-bone (BPTB) graft fixation strength of biodegradable pins compared with interference screws in anterior cruciate ligament reconstruction using bovine knees. Type of Study: Biomechanical in vitro study. Methods: Ten BPTB grafts from human donors fixed with 2 biodegradable 2.7-mm pins (Rigid Fix; Ethicon, Mitek Division, Norderstedt, Germany) crossing the bone block perpendicular and 10 BPTB grafts fixed with conventional biodegradable interference screws (Absolute Absorbable Interference Screw; Innovasive Devices, Marlborough, MA) underwent ultimate single-cycle failure loading at a rate of 200 mm/min. The grafts were fixed to bovine tibia to simulate young human femoral bone density. Failure mode, displacement before failure, and ultimate failure load were tested with a testing machine. The pullout force was in line with the bone tunnel to simulate a worst case scenario. Results: The failure mode for cross pins was either fracture of the bone block (5 specimens) or fracture of the articular pin (5 specimens). The failure mode for interference screws was slippage past the screw in all specimens. In the single cycle loading test, the mean yield load for the biodegradable pins was 400.2 (Ϯ 122.4) N, maximum load, 524.6 (Ϯ 136.6) N, with a mean stiffness of 155.2 (Ϯ 32.4) N/mm. The yield load at failure for the interference screw was 402.7 (Ϯ 143.9) N, maximum load 515.7 (Ϯ 168.5) N with a mean stiffness of 168 (Ϯ 42) N/mm. Conclusions: Fixation of a BPTB graft with 2 biodegradable 2.7-mm pins (Rigid Fix) leads to primary stability that is comparable to fixation with biodegradable interference screws.
Bioabsorbable Interference Screws for Graft Fixation in Anterior Cruciate Ligament Reconstruction
Arthroscopy: The Journal of Arthroscopic & Related Surgery, 1999
The central one third of the patellar tendon autograft is popular because the bone-tendon-bone (BTB) construct provides several graft fixation options, robust graft incorporation, and a mechanically sufficient substitute. Interference screw fixation is one method used to secure the graft. Bioabsorbable interference screws may offer advantages over metal interference screws. Bioabsorbable screws are made from poly L-lactic acid (PLLA) and are absorbed by the body. This prospective, randomized study compared the safety and efficacy of the PLLA screw with that of the metal cannulated interference screw for anterior cruciate ligament reconstruction. There were 204 patients randomly assigned to the Bioscrew (Linvatec, Largo, FL) (n ϭ 103) or the metal interference screw (n ϭ 101) groups at four sites. The mean age was 30 years. There were 66 women and 138 men. Mean follow-up was 30 months for Bioscrews and 28 months for metal screws; the average follow-up interval was 2.4 years. The Lysholm mean scores at 4 years for the 32 patients seen at this interval were 95.0 and 97.2 for the Bioscrew and metal screw group, respectively. Ligament laxity comparisons made with an instrumented arthrometer at manual maximum force resulted in side-to-side mean score differences of B ϭ 1.8mm and M ϭ 1.6mm. The Tegner activity level score means were B ϭ 6.1 and M ϭ 5.8. Other variables examined included pain, thigh size, meniscal tests, Lachman's test, range of motion, anterior drawer, pivot shift, patellofemoral crepitus and tenderness, and joint effusion. None of these variables showed a statistically significant difference between groups. No radiographic evidence of osteolytic change or bone resorption around the Bioscrews was observed. There were no complications related to loss of fixation, toxicity, allergenicity, or other evidence of osteolytic or inflammatory reaction. In every assessment between groups there was no difference found. There were 12 PLLA screws that broke during insertion without any adverse effects. The PLLA headless cannulated interference fit screws produce equal results to similarly designed metal screws.
Archives of Orthopaedic and Trauma Surgery, 2010
Introduction The application of interference screws for the Wxation of bone-patellar tendon-bone (BPTB) grafts is a well-established technique in anterior-cruciate ligament reconstruction. Interference screws derived from bovine compact bone are a biological alternative to metallic or biodegradable polymer interference screws. Materials and methods In 60 porcine specimens, the tibial part of an anterior-cruciate ligament reconstruction was performed using a BPTB graft. To secure the graft, either an 8-mm titanium interference screw or a self-made bovine interference screw (BC), or a commercial bovine compact bone screw (TutoWx ® ) was used. The maximum failure load was determined by means of a universal testing machine with computer interface at a testing speed of 50 mm/min. In a second test series, cyclic sub-maximal load was applied to the test specimen from 40 to 400 N with a number of 1,000 load cycles and a frequency of 1 Hz. Subsequently, the maximum failure load was determined. The stiVness of the test specimen was investigated in both test series. Each type of interference screw was tested 10 times.
Arthroscopy-the Journal of Arthroscopic and Related Surgery, 2006
Purpose: To compare the initial mechanical characteristics of 4 systems used to fix tendons to the femur during anterior cruciate ligament reconstruction. Methods: A total of 32 porcine femurs were used to study the following fixation systems: Bioabsorbable interference screw (Stryker, Kalamazoo, MI), Bio-Transfix Cross-pin (Arthrex, Naples, FL), Biosteon Cross-pin (Stryker), and a fixation technique based on wrapping the graft around the femoral condyle itself, thus allowing it to be fixed in place without the use of any hardware. The mechanical characteristics of each system were obtained by a preconditioned failure tensile test. Results: The yield load values (990.9 ± 242.6 N for Bio-Transfix, 905.1 ± 158.8 N for Biosteon Cross-pin, 684.4 ± 119.7 N for the without-hardware system (WHS), and 369.4 ± 120.1 N for the interference screw) revealed significant differences between the techniques that used cross-pins and the other 2 techniques (P < .006) on the one hand, and between the without hardware technique and the interference screw (P < .004) on the other. The stiffness of the 2 cross-pin fixation systems (117.6 ± 22.5 N for Bio-Transfix and 112.6 ± 22.5 N for Biosteon) was greater (P < .01) than those of the other systems (79.4 ± 15.2 N for the WHS and 68.5 ± 13 N for the interference screw). Conclusions: The initial biomechanical properties of the 2 cross-pin fixation systems proved to be superior to those of the other 2 systems studied. The WHS fixation system exhibited better mechanical properties than its interference screw counterpart. Clinical Relevance: The better initial mechanical characteristics encountered using the Bio-Transfix and Biosteon Cross-pin systems indicate that these systems are better equipped to bear the loads generated by aggressive rehabilitation. The WHS fixation system provides an alternative to interference screw fixation.
Testing of prototype interference screw for ACL reconstruction in porcine femurs
2012
Multiple techniques for the reconstruction of anterior cruciate ligament (ACL) are available, most of which use implant made from metallic or bioabsorbable materials. Currently one of the most widely used fi xation methods for anterior cruciate ligament reconstruction with bone tendonbone graft is the interference screw. The aim of our work was to test custom design screw geometry, whether it is appropriate for ACL reconstruction. New screw was designed geometry for the work, so that screws with the same geometry could be produced for later work, from different materials. In this study injection molded biodegradable interference screws were tested on porcine femurs, with bone-patellar tendon-bone (BPTB) graft fi xation. The average failure load and the stiffness (772 ± 225 N and 109 ± 33.9 N/mm respectively) of the fi xation was higher than literature average, although within standard deviation. Test results showed that the designed screw geometry is adequate for BPTB graft fi xation.
Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2006
The purpose of this study was to evaluate the effect of hybrid femoral fixation with bioabsorbable interference screws (BioRCI; Smith & Nephew Endoscopy, Andover, MA) and EndoButton CL (Smith & Nephew Endoscopy) fixation. Methods: Biomechanical testing of 3 different fixation techniques was performed by use of porcine hind-limb distal femurs and mature bovine extremity common extensor tendons. Two independent testing sessions were examined. The first testing session (group A) compared femoral fixation via the EndoButton CL device (n ϭ 6) with femoral fixation via the EndoButton CL device with the addition of a BioRCI screw (n ϭ 6). The second testing session (group B) compared femoral fixation via BioRCI screws alone (n ϭ 6) with femoral fixation via the EndoButton CL device with the addition of a BioRCI screw (n ϭ 6). The femur-graft complex was cyclically loaded between 50 and 250 N at 1 Hz for 1,000 cycles. After cycling, the amount of graft slippage was determined by measuring the change in grip-to-grip distance. The complex was then loaded to failure at 1 mm/s, and the ultimate tensile strength, stiffness, and mode of failure were determined. Results: In group A the addition of an interference screw to the EndoButton CL fixation increased the ultimate tensile strength (1,364.7 Ϯ 102.4 N for EndoButton CL alone v 1,449.3 Ϯ 94.4 N for combined technique, P ϭ .035) and stiffness (195.5 Ϯ 12.1 N/mm for EndoButton CL alone v 307.3 Ϯ 54.9 N/mm for combined technique, P ϭ .004) and decreased the amount of graft slippage (2.6 Ϯ 0.5 mm for EndoButton CL alone v 2.0 Ϯ 0.3 mm for combined technique, P ϭ .017). In group B the addition of the EndoButton CL device to interference screw fixation significantly increased the ultimate tensile strength (643.5 Ϯ 148.4 N for BioRCI screws alone v 1,290.3 Ϯ 254.4 N for combined technique, P ϭ .004) but had no effect on stiffness (315.7 Ϯ 38.9 N/mm for BioRCI screws alone v 341.5 Ϯ 64.0 N/mm for combined technique, P ϭ .267) or graft slippage (2.7 Ϯ 1.0 mm for BioRCI screws alone v 2.0 Ϯ 0.6 mm for combined technique, P ϭ .087). Conclusions: Our study shows that hybrid femoral fixation of double-looped gracilis-semitendinosus grafts via the EndoButton CL device and a bioabsorbable interference screw is stronger than interference or EndoButton CL fixation alone with respect to ultimate tensile strength, stiffness, and slippage. The addition of an interference screw to suspensory fixation via the EndoButton CL device increased the ultimate tensile strength from 1,360 N to 1,450 N, improved reconstruction stiffness from 200 N/mm to 300 N/mm, and decreased the amount of graft slippage resulting from cyclic loading from 2.6 mm to 2.0 mm. Clinical Relevance: The hybrid fixation of the EndoButton CL device and an interference screw is a stronger and stiffer construct than either device alone and allows for aperture fixation, which may translate into better clinical results.
Archives of bone and joint surgery, 2015
Ligament reconstruction is a common procedure in orthopedic surgery. Although several popular techniques are currently in use, new methods are proposed for secure fixation of the tendon graft into the bone tunnel. We sought to introduce our new technique of Bashti bone plug for fixation of soft tissue graft in anterior cruciate ligament (ACL) reconstruction and to compare its biomechanical features with conventional absorbable interference screw technique in a bovine model. Twenty pairs of bovine knees were harvested after death. Soft tissue was removed and the Achilles tendon was harvested to be used as an ACL graft. It was secured into the bone tunnel on the tibial side via two different methods: Bashti Bone Plug technique and conventional screw method. Biomechanical strength was measured using 200 N and 300 N cyclic loading on the graft. Pull out strength was also tested until the graft fails. No graft failure was observed after 200 N and 300 N cyclic loading in either fixation m...