scholarly journals Biomechanical properties of a novel biodegradable magnesium-based interference screw

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
Marco Ezechieli ◽  
Hanna Meyer ◽  
Arne Lucas ◽  
Patrick Helmecke ◽  
Christoph Becher ◽  
...  

Magnesium-based interference screws may be an alternative in anterior/posterior cruciate ligament reconstruction. The well-known osteoconductive effects of biodegradable magnesium alloys may be useful. It was the purpose of this study to evaluate the biomechanical properties of a magnesium based interference screw and compare it to a standard implant. A MgYREZr-alloy interference screw and a standard implant (Milagro®; De Puy Mitek, Raynham, MA, USA) were used for graft fixation. Specimens were placed into a tensile loading fixation of a servohydraulic testing machine. Biomechanical analysis included pretensioning of the constructs at 20 N for 1 min following cyclic pretensioning of 20 cycles between 20 and 60 N. Biomechanical elongation was evaluated with cyclic loading of 1000 cycles between 50 and 200 N at 0.5 Hz. Maximum load to failure was 511.3±66.5 N for the Milagro® screw and 529.0±63.3 N for magnesium-based screw (ns, P=0.57). Elongations after preload, during cyclical loading and during failure load were not different between the groups (ns, P>0.05). Stiffness was 121.1±13.8 N/mm for the magnesiumbased screw and 144.1±18.4 for the Milagro® screw (ns, P=0.32). MgYREZr alloy interference screws show comparable results in biomechanical testing to standard implants and may be an alternative for anterior cruciate reconstruction in the future.

2018 ◽  
Vol 46 (8) ◽  
pp. 1857-1862 ◽  
Author(s):  
Dayne T. Mickelson ◽  
Thomas Lefebvre ◽  
Ken Gall ◽  
Jonathan C. Riboh

Background: Adjustable-loop cortical buttons for femoral fixation of bone-tendon-bone grafts have potential advantages over interference screw fixation; however, these devices have not been benchmarked biomechanically against interference screws. Purpose/Hypothesis: The purpose was to compare the time zero biomechanical properties of commercially available, adjustable-loop cortical button and metallic interference screws for femoral fixation of bone-tendon-bone grafts. It was hypothesized that no significant differences would be found in biomechanical properties between fixation techniques. Study Design: Controlled laboratory study. Methods: Adjustable-loop cortical buttons (n = 8) and metallic interference screws (n = 8) were used to fix matched pairs of human bone-tendon-bone allografts in porcine distal femurs. These constructs were preconditioned (10 N to 50 N at 1 Hz, 10 cycles), subjected to cyclic loading (50 N to 250 N at 1 Hz, 500 cycles), and then pulled to failure at 20 mm/min. Results: The loads to failure (mean ± SD, 700 ± 256 N vs 688 ± 215 N, P = .92) and linear stiffnesses (219 ± 48 N/mm vs 218 ± 49 N/mm, P = .97) for the adjustable-loop cortical button and metallic interference screws, respectively, were not significantly different. Cyclic displacement was higher in the adjustable-loop cortical button group (2.1 ± 0.6 mm vs 1.3 ± 0.4 mm, P = .01). The mechanism of failure was different between groups, with bone block slippage occurring most commonly in the interference screw group (n = 5) and fracture of the bone block through the suture hole occurring most commonly in the adjustable-loop cortical button group (n = 6). Conclusion: Adjustable-loop cortical buttons and interference screws have similar time zero failure loads, although cyclic displacement was higher with the adjustable-loop cortical buttons. The mean difference in displacement was less than 1 mm compared with the interference screw. Clinical Relevance: Adjustable-loop cortical buttons may be an acceptable alternative to an interference screw for femoral fixation of bone-tendon-bone grafts in anterior cruciate ligament reconstruction. The clinical relevance of the observed differences in cyclic displacement is unknown and should be evaluated in future studies.


2018 ◽  
Vol 6 (8) ◽  
pp. 232596711878881 ◽  
Author(s):  
Mark E. Steiner ◽  
David Wing ◽  
Kempland C. Walley ◽  
Ohan Manoukian ◽  
Miguel Perez-Viloria ◽  
...  

Background: In anatomic anterior cruciate ligament (ACL) reconstructions produced with flexible reamers and no knee hyperflexion, it is unknown whether knee hyperflexion is necessary for femoral interference screw insertion. Purpose: To compare femoral screw-graft divergence in anatomic ACL reconstructions with endoscopic interference screws placed without knee hyperflexion and with the use of flexible versus rigid screwdrivers. Study Design: Controlled laboratory study. Methods: Ten matched pairs of cadaveric knees had bone-tendon-bone graft ACL reconstructions with anatomic femoral tunnels. The knees were flexed to 90°. Femoral interference screws (7 × 20 mm) were placed in pairs of knees: in 1 knee with a flexible screwdriver and in the opposite knee with a rigid screwdriver. Graft-screw divergence was imaged with computed tomography scans and tested with cyclic and static biomechanical tests. Results: The mean screw-graft divergence was 12.07° ± 4.04° with the rigid screwdriver and 10.68° ± 3.23° with the flexible screwdriver ( P = .35). The cyclic tests with screws placed by a rigid screwdriver had a mean increase in displacement of 0.56 ± 0.20 mm. For screws placed with the flexible screwdriver, the mean increase in displacement was 0.58 ± 0.32 mm ( P = .66). Yield load was 393.3 ± 95.1 N for screws placed by a rigid screwdriver and 408.2 ± 119.0 N for screws inserted with the flexible screwdriver ( P = .78). Maximum load was 523.1 ± 88.7 N for screws placed by a rigid screwdriver and 467.1 ± 107.3 N for screws inserted with the flexible screwdriver ( P = .09). Conclusion: With either a rigid or a flexible screwdriver, there were no significant effects on screw divergence or fixation strength. Clinical Relevance: Knees can be kept at 90° during endoscopic femoral interference screw insertion. The use of a traditional rigid or flexible screwdriver will not affect screw-graft divergence or fixation strength.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yuanjun Teng ◽  
Xiaohui Zhang ◽  
Lijun Da ◽  
Jie Hu ◽  
Hong Wang ◽  
...  

Abstract Background Interference screw is commonly used for graft fixation in anterior cruciate ligament (ACL) reconstruction. However, previous studies had reported that the insertion of interference screws significantly caused graft laceration. The purposes of this study were to (1) quantitatively evaluate the graft laceration from one single insertion of PEEK interference screws; and (2) determine whether different types of sutures reduced the graft laceration after one single insertion of interference screws in ACL reconstruction. Methods The in-vitro ACL reconstruction model was created using porcine tibias and bovine extensor digitorum tendons of bovine hind limbs. The ends of grafts were sutured using three different sutures, including the bioabsorbable, Ethibond and ultra-high molecular weight polyethylene (UHMWPE) sutures. Poly-ether-ether-ketone (PEEK) interference screws were used for tibial fixation. This study was divided into five groups (n = 10 in each group): the non-fixed group, the non-sutured group, the absorbable suture group, the Ethibond suture group and the UHMWPE suture group. Biomechanical tests were performed using the mode of pull-to-failure loading tests at 10 mm/min. Tensile stiffness (newtons per millimeter), energy absorbed to failure (in joules) and ultimate load (newtons) were recorded for analysis. Results All prepared tendons and bone specimens showed similar characteristics (length, weight, and pre-tension of the tendons, tibial bone mineral density) among all groups (P > 0.05). The biomechanical tests demonstrated that PEEK interference screws significantly caused the graft laceration (P < 0.05). However, all sutures (the bioabsorbable, Ethibond and UHMWPE sutures) did not reduce the graft laceration in ACL reconstruction (P > 0.05). Conclusions Our biomechanical study suggested that the ultimate failure load of grafts was reduced of approximately 25 % after one single insertion of a PEEK interference screw in ACL reconstruction. Suturing the ends of the grafts using different sutures (absorbable, Ethibond and UHMWPE sutures) did not decrease the graft laceration caused by interference screws.


2020 ◽  
Vol 45 (10) ◽  
pp. 1061-1065
Author(s):  
Eivind Strandenes ◽  
Peter Ellison ◽  
Anders O. Mølster ◽  
Nils R. Gjerdet ◽  
Irene O. Moldestad ◽  
...  

The aim of the study was to compare side-to-side with step-cut repairs to determine how much of the width it is possible to remove and still keep the repair strong enough to start active mobilization. Porcine flexor tendons were used to create side-to-side, one-third step-cut and half step-cut repairs. There were 15 repairs in each group. The tensile properties of the constructs were measured in a biomechanical testing machine. All repairs failed by the sutures splitting the tendon longitudinally. The maximum load and stiffness were highest in the side-to-side group. Our findings suggest that the half step-cut repair can withstand the forces exerted during active unrestricted movement of the digits in tendons of this size. The advantage of the step-cut repair is reduced bulkiness and less friction, which might compensate for the difference in strength.


2021 ◽  
Author(s):  
Yuanjun Teng ◽  
Lijun Da ◽  
Xiaohui Zhang ◽  
Hong Wang ◽  
Hua Han ◽  
...  

Abstract Background: Interference screw is commonly used for graft fixation in anterior cruciate ligament (ACL) reconstruction However, previous studies h a d reported that the insertion of interference screws significantly caused graft laceration . The purpose of this study was to determine whether sutures reduce d the graft laceration from the insertion of interference screws in ACL reconstruction. Methods: Porcine tibias and bovine extensor tendons were used for establishing a knee model of ACL reconstruction in vitro . The ends of grafts were sutured using three different sutures, including the bioabsorbable, Ethibond and ultra high molecular weight polyethylene (UHMWPE) sutures Poly ether ether ketone (PEEK) interference screw s w ere used fortibial fixation Biomechanical tests were performed to investigate the protective effects of different sutures on grafts Results : All prepared tendons and bone specimens showed similar characteristics (length, weight, and pre tension of the tendons, tibial bone mineral density) among all groups ( P 0.05). The biomechanical test s demonstrated that PEEK interference screw s significantly caused the graft laceration P 0.05). However, all sutures (the bioabsorbable, Ethibond and UHMWPE sutures) did not reduce the graft laceration in ACL reconstruction P 0.05). Conclusions : PEEK interference screw s significantly weakened the biomechanical properties of grafts during tibial fixation in ACL reconstruction. Absorbable Ethibond and UHMWPE sutures did not provide protective effects on grafts during ACL reconstruction.


2019 ◽  
Vol 32 (02) ◽  
pp. 112-116
Author(s):  
Brian Bufkin ◽  
Alan Litsky ◽  
Matthew Barnhart

Objective The aim of this study was to compare the biomechanical properties of four different methods of artificial cranial cruciate ligament fixation in canine cadaveric tibias and femurs. Methods Femurs and tibias from skeletally mature large breed canine cadavers were assigned into four fixation groups: group 1, 4.5-mm interference screw (IS); group 2, 4.5-mm IS and 4.0-mm screw and spiked washer (SW); group 3, 5.0-mm IS; group 4, 5.0-mm IS + SW. Results The mean ultimate load was significantly greater for femur fixations than for tibias, when a SW was added, and for 5.0-mm IS compared with 4.5-mm sizes. There was also a significant interaction between SW and IS size. A SW significantly increased stiffness, a 5.0-mm IS in femurs provided more stiffness than 4.5-mm IS and was greater than 5.0-mm IS in tibias. In tibias, a 4.5-mm IS was stiffer than a 5.0-mm IS and a 4.5 IS + SW had greater stiffness than a 5.0-mm IS + SW. Groups 1 to 3 and tibias in group 4 failed by artificial ligament pullout. Nine femurs in group 4 failed by fracture, 5 by artificial ligament pullout, and 1 by artificial ligament tearing. Clinical Significance A 5.0-mm IS + SW provided superior artificial ligament fixation strength in femurs and tibias compared with a 4.5-mm IS without SW. Overall, artificial ligament fixation with 5.0-mm IS in femurs had the mechanical characteristics that most closely matched those reported in normal canine cranial cruciate ligaments.


2005 ◽  
Vol 33 (4) ◽  
pp. 574-582 ◽  
Author(s):  
Andrea Ferretti ◽  
Fabio Conteduca ◽  
Luca Labianca ◽  
Edoardo Monaco ◽  
Angelo De Carli

Background The weakest points in hamstrings anterior cruciate ligament reconstruction are its points of fixation, especially on the tibial side. Methods for graft fixation to bone should be strong enough to avoid failure, stiff enough to restore load-displacement response, and secure enough to resist slippage under cyclic loading. Hypothesis Biomechanical properties of the interference screw can be improved by reinforcing the walls of the tunnel with a metal spiral (Evolgate fixation). Study Design Controlled laboratory study. Methods Three paired tests were performed using common digital extensor bovine tendons fixed to porcine tibias with interference screw, Intrafix, and Evolgate; critical graft fixation conditions were simulated by applying subsequent cycles to the graft before loading the graft until failure. Results The strength, stiffness, and resistance to slippage of the Evolgate were significantly higher than those of the interference screw; the ultimate failure load of the Evolgate was significantly higher than that of the Intrafix (1058 ± 130 N and 832 ± 156 N, respectively; P =. 02). No statistically significant differences were found between Evolgate and Intrafix regarding the stiffness and slippage under cyclic load. Conclusion Evolgate fixation seems to be stronger, stiffer, and more resistant to slippage than is interference screw fixation of similar length, and it is stronger but not stiffer than Intrafix. Clinical Relevance The Evolgate provides structural properties that seem to be appropriate for an intensive rehabilitation after anterior cruciate ligament reconstruction using a doubled semitendinosus and gracilis graft.


2021 ◽  
Vol 8 (18) ◽  
pp. 1258-1263
Author(s):  
Vishal Singh ◽  
Alokeshwar Sharma ◽  
Avinash Gundavarapu ◽  
Tejas Patel ◽  
Santosh Kumar M

BACKGROUND Traditionally, metallic interference screws were considered to have increased resistance to load than bio absorbable screws in anterior cruciate ligament (ACL) reconstruction. We did a comparative evaluation of biodegradable and metallic interference screws for tibial sided ACL reconstruction and also analysed complications, compared clinical outcome, did imaging study of ACL single bundle reconstruction by using titanium & newer poly–L-lactic acid (PLLA) bio absorbable screws to determine as to whether bio absorbable screw which costs double the metallic screw, is functionally better than standard metallic screws. METHODS This is a prospective comparative study conducted among 50 patients aged between 15 and 55 years with clinical and MRI confirmation of complete ACL tear, treated arthroscopically with ACL reconstruction with either bio absorbable (group 1) or metallic (group 2) interference screw and both the groups were compared on follow up for an average duration of 12 months. Lysholm and Gillquist Knee Scoring Scale were used and outcome scores were divided into excellent, good, fair and poor. RESULTS In our study 41 patients were males and 9 were females. Bio screw was used in 24 males and 6 female patients. Metallic screw was used in 17 males and 3 females. Outcome score was excellent in 26 (52 %) cases, good in 18 (36 %) cases, fair in 4 (8 %) cases, poor in 2 (4 %) cases. The mean Lysholm score in bio absorbable group was 93.13 and in metallic group was 89.70. Knee effusion was higher in bio screw group and infection rate was higher in metallic group. CONCLUSIONS In our study, the difference between bio absorbable screw group and metallic screw group was insignificant with regard to final patient outcome. Final osseointegration was better with bio absorbable screw, but increased cost of implant and almost same results compared to metallic screw does not make the bio absorbable screw superior to its counterpart. KEYWORDS ACL, Bio Absorbable Interference Screws, Metallic Interference Screws


2018 ◽  
Vol 6 (6) ◽  
pp. 232596711877695
Author(s):  
Alex G. Dukas ◽  
Kevin G. Shea ◽  
Carl W. Nissen ◽  
Elifho Obopilwe ◽  
Peter D. Fabricant ◽  
...  

Background: Anterior cruciate ligament (ACL) ruptures have become increasingly common in pediatric and adolescent athletes. While multiple methods exist, all-epiphyseal ACL reconstruction is a popular technique in the skeletally immature patient. Given the high rate of reruptures in this population and the increasing number of commercially available fixation devices, biomechanical testing is crucial to understand the performance of these devices in pediatric epiphyseal bone. To our knowledge, there has not been a biomechanical analysis of ACL fixation devices in skeletally immature bone. Purpose: To compare cortically based button fixation with interference screw and sheath fixation in skeletally immature femoral epiphyseal cadaveric bone. Our hypothesis was that there would be no difference in peak load to failure, stiffness, or cyclic displacement between these 2 fixation constructs. Study Design: Controlled laboratory study. Methods: Fresh-frozen matched-pair knees from 3 pediatric cadaveric specimens were obtained. A synthetic graft was fixed in an all-epiphyseal femoral tunnel. Both the lateral and medial condyles were utilized to increase the sample size. Specimens were randomized and assigned to receive either an interference screw and sheath construct designed for pediatric patients or an adjustable loop cortical button. Biomechanical testing was performed to obtain ultimate load to failure, stiffness, total displacement after 500 cycles, and the failure mode for each condyle. Results: Each medial and lateral condyle in 3 pairs of skeletally immature cadaveric knees (ages 7, 9, and 11 years) was utilized for testing. One specimen was excluded after it failed by having a transphyseal fracture. The median peak load to failure was 769.80 N (interquartile range [IQR], 628.50-930.41 N) for the screw and sheath group and 862.80 N (IQR, 692.34-872.65 N) for the button group ( P = .893). The median displacement after 500 cycles for the screw and sheath group was 0.65 mm (IQR, 0.47-1.03 mm) and 1.13 mm (IQR, 0.96-1.25 mm) for the button group ( P = .08). The median stiffness of the screw and sheath group was significantly higher than that of the button group (31.47 N/mm [IQR, 26.40-43.00 N/mm] vs 25.22 N/mm [IQR, 21.18-27.07 N/mm], respectively) ( P = .043). Conclusion: When comparing femoral fixation with a screw and sheath construct developed for pediatric patients to an adjustable loop cortical button in skeletally immature bone, our results showed that fixation did not significantly differ with respect to cyclic displacement or peak load to failure. While the screw and sheath construct was significantly stiffer, its effect on clinical outcomes is not yet known. Clinical Relevance: With regard to femoral fixation, there is no significant biomechanical difference between the use of cortically based button fixation or interference screw and sheath fixation in pediatric epiphyseal cadaveric bone.


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