The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Andrea Ferretti - One of the best experts on this subject based on the ideXlab platform.
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Anterior cruciate ligament reconstruction is associated with greater tibial tunnel widening when using a Bioabsorbable Screw compared to an all-inside technique with suspensory fixation
Knee Surgery Sports Traumatology Arthroscopy, 2019Co-Authors: Edoardo Monaco, Mattia Fabbri, Andrea Redler, Edoardo Gaj, Giuseppe Argento, Angelo De Carli, Adnan Saithna, Andrea FerrettiAbstract:PurposeTo compare clinical outcomes and tunnel widening following anterior cruciate ligament reconstruction (ACLR) performed with an all-inside technique (Group A) or with a Bioabsorbable tibial Screw and suspensory femoral fixation (Group B).MethodsTunnel widening was assessed using computed tomography (CT) and a previously validated analytical best fit cylinder technique at approximately 1-year following ACLR. Clinical follow-up comprised evaluation with IKDC, KSS, Tegner, Lysholm scores, and knee laxity assessment.ResultsThe study population comprised 22 patients in each group with a median clinical follow-up of 24 months (range 21–27 months). The median duration between ACLR and CT was 13 months (range 12–14 months). There were no significant differences in clinical outcome measures between groups. There were no differences between groups with respect to femoral tunnel widening. However, there was a significantly larger increase in tibial tunnel widening, at the middle portion, in Group B (2.4 ± 1.5 mm) compared to Group A (0.8 ± 0.4 mm) ( p = 0.027), and also at the articular portion in Group B (1.5 ± 0.8 mm) compared to Group A (0.8 ± 0.8 mm) ( p = 0.027).ConclusionTibial tunnel widening after ACLR using hamstring tendon autograft is significantly greater with suspensory femoral fixation and a Bioabsorbable tibial interference Screw when compared to an all-inside technique at a median follow-up of 2 years. The clinical relevance of this work lies in the rebuttal of concerns arising from biomechanical studies regarding the possibility of increased tunnel widening with an all-inside technique.Level of evidenceIII.
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anterior cruciate ligament reconstruction is associated with greater tibial tunnel widening when using a Bioabsorbable Screw compared to an all inside technique with suspensory fixation
Knee Surgery Sports Traumatology Arthroscopy, 2019Co-Authors: Edoardo Monaco, Mattia Fabbri, Andrea Redler, Giuseppe Argento, Angelo De Carli, Adnan Saithna, Andrea FerrettiAbstract:To compare clinical outcomes and tunnel widening following anterior cruciate ligament reconstruction (ACLR) performed with an all-inside technique (Group A) or with a Bioabsorbable tibial Screw and suspensory femoral fixation (Group B). Tunnel widening was assessed using computed tomography (CT) and a previously validated analytical best fit cylinder technique at approximately 1-year following ACLR. Clinical follow-up comprised evaluation with IKDC, KSS, Tegner, Lysholm scores, and knee laxity assessment. The study population comprised 22 patients in each group with a median clinical follow-up of 24 months (range 21–27 months). The median duration between ACLR and CT was 13 months (range 12–14 months). There were no significant differences in clinical outcome measures between groups. There were no differences between groups with respect to femoral tunnel widening. However, there was a significantly larger increase in tibial tunnel widening, at the middle portion, in Group B (2.4 ± 1.5 mm) compared to Group A (0.8 ± 0.4 mm) (p = 0.027), and also at the articular portion in Group B (1.5 ± 0.8 mm) compared to Group A (0.8 ± 0.8 mm) (p = 0.027). Tibial tunnel widening after ACLR using hamstring tendon autograft is significantly greater with suspensory femoral fixation and a Bioabsorbable tibial interference Screw when compared to an all-inside technique at a median follow-up of 2 years. The clinical relevance of this work lies in the rebuttal of concerns arising from biomechanical studies regarding the possibility of increased tunnel widening with an all-inside technique. III.
David N M Caborn - One of the best experts on this subject based on the ideXlab platform.
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Bioabsorbable Screw divergence angle not tunnel preparation method influences soft tissue tendon graft bone tunnel fixation in healthy bone
Knee Surgery Sports Traumatology Arthroscopy, 2007Co-Authors: Andrew R Duffee, John Nyland, Jeffrey A Brunelli, Robert Burden, Akbar Nawab, David N M CabornAbstract:Bone tunnel fixation of a soft tissue tendon graft is the weak link immediately following ACL reconstruction. This biomechanical study evaluated the influence of extraction drilled or step dilated bone tunnels and Bioabsorbable Screw divergence on soft tissue tendon graft fixation. From an initial group of 50 available specimens, similar apparent bone mineral density porcine tibiae (1.2 ± 0.24 g/cm2) were divided into two groups of ten specimens each. Group 1 (extraction drilled) received 9 mm diameter tunnels. Group 2 (step dilated) received 7 mm diameter tunnels that were dilated to 9 mm. Grafts were secured in tunnels using 10 mm diameter, 35 mm long tapered Screws. After high resolution CT scanning to evaluate Screw divergence, constructs were pretensioned on a servo hydraulic device between 10 and 50 N for 10 cycles, and isometric pretensioned at 50 N for 1 min, prior to 500 sub-maximal loading cycles (50–200 N) and load to failure testing at 20 mm/min. Wilcoxon Signed Rank tests and Mann–Whitney U-tests were used to evaluate group differences. Coefficient of determination values (r 2) were calculated to further delineate statistically significant relationships. Tunnel preparation method did not display statistically significant effects on insertion torque, displacement during cyclic testing, relative stiffness during cyclic testing, load at failure, stiffness during load to failure testing or displacement during load to failure testing. Screw divergence < 15° produced lower displacement and greater relative stiffness during cyclic testing and greater load at failure and stiffness during load to failure testing. Screw divergence angle displayed moderate relationships with construct displacement during cyclic testing (r 2 = 0.54), stiffness during load to failure testing (r 2 = 0.60), and load at failure (r 2 = 0.41). Tunnel dilation does not enhance soft tissue tendon graft fixation strength in healthy bone. Bioabsorbable Screw divergence of ≥ 15° significantly reduces soft tissue tendon graft-bone tunnel fixation.
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soft tissue interference fixation Bioabsorbable Screw versus metal Screw
Arthroscopy, 2005Co-Authors: Jeff C Brand, John Nyland, David N M Caborn, Darren L JohnsonAbstract:Purpose: To compare the biomechanical properties of eccentrically positioned Bioabsorbable and titanium interference Screws for quadrupled hamstring tendon graft (QHTG) fixation. Type of Study: In vitro, biomechanical study. Methods: In 10 paired cadaveric tibiae and femurs (mean age, 66.5 years; range, 53 to 81 years), QHTG fixation was performed in tunnels sized to within 0.5 mm of QHTG diameter using either a titanium (RCI; Smith & Nephew Donjoy, Carlsbad, CA) or a Bioabsorbable (BioScrew; Linvatec, Largo, FL) Screw of equal size. Constructs then underwent biomechanical load-to-failure testing on a servo-hydraulic device at 20 mm/min. Results: Load at failure was greater for femoral-side QHTG fixation using the Bioabsorbable Screw than the titanium Screw (486 ± 223.7 N v 246 ± 99.1 N, P = .006); however, displacement did not differ ( P = .81). There were no statistically significant differences between groups for tibial side load at failure ( P = .54), stiffness ( P = .44), or displacement ( P = .50). Screw thread-induced graft laceration was more frequently observed in the titanium Screw group (9 of 10 grafts during femoral-side testing, 0 of 10 grafts during tibial-side testing) than in the Bioabsorbable Screw group (0 of 10 grafts during femoral-side testing, 1 of 10 grafts during tibial-side testing). Conclusions: BioScrew interference Screw fixation was comparable or superior to RCI titanium interference Screw fixation. BioScrew interference Screw fixation also produced less Screw thread-induced laceration of the QHTG during load-to-failure testing. Clinical Relevance: Use of a biodegradable interference Screw positioned directly against a soft-tisse graft provides fixation properties similar to those of a metal interference Screw.
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soft tissue tendon graft fixation in the tibial tunnel with a Bioabsorbable Screw endopearl combination in tibiae of low bone mineral density a biomechanical study
Acta Orthopaedica et Traumatologica Turcica, 2004Co-Authors: Yavuz Kocabey, John Nyland, Akbar Nawab, Erdem U Isikan, David N M CabornAbstract:Objectives: This biomechanical study evaluated soft tissue tendon graft fixation in the tibial tunnel using a Bioabsorbable interference Screw with or without supplemental EndoPearl device. Methods: Ten bovine tibiae were stripped of all soft tissues and bone tunnels 7 mm in diameter were drilled with dilation to 9 mm. Tibialis anterior allografts were fixed with a Screw (10 mm in diameter, 30 mm in length) in five tibiae of high bone mineral density (1.36 g/cm2), and with a Screw-EndoPearl combination in five tibiae of low bone mineral density (0.84 g/cm2). The specimens were cycled 10 times from 10 to 50 N, and 500 times from 50 to 200 N in a servo hydraulic test device prior to ultimate load-at-failure testing at a rate of 20 mm/min. Results: No statistically significant differences were found between the two fixation groups with respect to displacement and stiffness during cyclic testing, and with respect to load at failure, displacement, and stiffness during load-to-failure testing (p>0.05). Conclusion: The finding of similar results in both fixation groups with respect to displacement and stiffness during cyclic testing and during load-to-failure testing suggests that a Screw-EndoPearl combination in tibiae of low bone mineral density may be helpful in the prevention of graft slippage.
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quadrupled semitendinosus gracilis autograft fixation in the femoral tunnel a comparison between a metal and a Bioabsorbable interference Screw
Arthroscopy, 1998Co-Authors: David N M Caborn, John Nyland, Michael J Coen, R Neef, Doris Hamilton, Darren L JohnsonAbstract:Abstract Although semitendinosus-gracilis (SG) grafts for anterior cruciate ligament reconstruction have many potential benefits, effective fixation remains a challenge. This study assessed differences between the maximum pullout forces needed to detach a quadrupled SG graft from a femoral tunnel when secured by either a metal or a Bioabsorbable interference Screw. Sixteen paired fresh frozen quadrupled SG autografts (x, 8.4 mm; range, 7-10 mm) from 8 donors were anchored into cadaveric femoral tunnels by either a 7-mm metal or a 7-mm Bioabsorbable Screw after bone mineral density (BMD) assessment and before undergoing a longitudinal 20 mm/min traction force. Statistical analysis compared BMD (gm/cm2), insertional torque (N-m), and maximum load at pullout (N) between Screw types. Insertional torques (.28-1.21, N-m range) did not correlate ( P >.05) to BMD or maximum load at pullout (x ± S.D.) 242 ± 90.7 N (metal Screw) and 341.1 ± 162.9 N (Bioabsorbable Screw). Differences did not exist between the maximum load at pullout for Bioabsorbable or metal Screw fixation ( P = .16). Careful graft preparation, sizing, and matched tunnel placement enables interference fit and fixation capable of reliably withstanding the low- level rehabilitation loads to which the graft is exposed until bony ingrowth occurs. Arthroscopy 1998 Apr;14(3):241-5
Andrew R Duffee - One of the best experts on this subject based on the ideXlab platform.
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Bioabsorbable Screw divergence angle not tunnel preparation method influences soft tissue tendon graft bone tunnel fixation in healthy bone
Knee Surgery Sports Traumatology Arthroscopy, 2007Co-Authors: Andrew R Duffee, John Nyland, Jeffrey A Brunelli, Robert Burden, Akbar Nawab, David N M CabornAbstract:Bone tunnel fixation of a soft tissue tendon graft is the weak link immediately following ACL reconstruction. This biomechanical study evaluated the influence of extraction drilled or step dilated bone tunnels and Bioabsorbable Screw divergence on soft tissue tendon graft fixation. From an initial group of 50 available specimens, similar apparent bone mineral density porcine tibiae (1.2 ± 0.24 g/cm2) were divided into two groups of ten specimens each. Group 1 (extraction drilled) received 9 mm diameter tunnels. Group 2 (step dilated) received 7 mm diameter tunnels that were dilated to 9 mm. Grafts were secured in tunnels using 10 mm diameter, 35 mm long tapered Screws. After high resolution CT scanning to evaluate Screw divergence, constructs were pretensioned on a servo hydraulic device between 10 and 50 N for 10 cycles, and isometric pretensioned at 50 N for 1 min, prior to 500 sub-maximal loading cycles (50–200 N) and load to failure testing at 20 mm/min. Wilcoxon Signed Rank tests and Mann–Whitney U-tests were used to evaluate group differences. Coefficient of determination values (r 2) were calculated to further delineate statistically significant relationships. Tunnel preparation method did not display statistically significant effects on insertion torque, displacement during cyclic testing, relative stiffness during cyclic testing, load at failure, stiffness during load to failure testing or displacement during load to failure testing. Screw divergence < 15° produced lower displacement and greater relative stiffness during cyclic testing and greater load at failure and stiffness during load to failure testing. Screw divergence angle displayed moderate relationships with construct displacement during cyclic testing (r 2 = 0.54), stiffness during load to failure testing (r 2 = 0.60), and load at failure (r 2 = 0.41). Tunnel dilation does not enhance soft tissue tendon graft fixation strength in healthy bone. Bioabsorbable Screw divergence of ≥ 15° significantly reduces soft tissue tendon graft-bone tunnel fixation.
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Bioabsorbable Screw divergence angle, not tunnel preparation method influences soft tissue tendon graft-bone tunnel fixation in healthy bone
Knee Surgery Sports Traumatology Arthroscopy, 2007Co-Authors: Andrew R Duffee, John Nyland, Jeffrey A Brunelli, Robert Burden, Akbar Nawab, David CabornAbstract:Bone tunnel fixation of a soft tissue tendon graft is the weak link immediately following ACL reconstruction. This biomechanical study evaluated the influence of extraction drilled or step dilated bone tunnels and Bioabsorbable Screw divergence on soft tissue tendon graft fixation. From an initial group of 50 available specimens, similar apparent bone mineral density porcine tibiae (1.2 ± 0.24 g/cm^2) were divided into two groups of ten specimens each. Group 1 (extraction drilled) received 9 mm diameter tunnels. Group 2 (step dilated) received 7 mm diameter tunnels that were dilated to 9 mm. Grafts were secured in tunnels using 10 mm diameter, 35 mm long tapered Screws. After high resolution CT scanning to evaluate Screw divergence, constructs were pretensioned on a servo hydraulic device between 10 and 50 N for 10 cycles, and isometric pretensioned at 50 N for 1 min, prior to 500 sub-maximal loading cycles (50–200 N) and load to failure testing at 20 mm/min. Wilcoxon Signed Rank tests and Mann–Whitney U -tests were used to evaluate group differences. Coefficient of determination values ( r ^2) were calculated to further delineate statistically significant relationships. Tunnel preparation method did not display statistically significant effects on insertion torque, displacement during cyclic testing, relative stiffness during cyclic testing, load at failure, stiffness during load to failure testing or displacement during load to failure testing. Screw divergence
John Nyland - One of the best experts on this subject based on the ideXlab platform.
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Bioabsorbable Screw divergence angle, not tunnel preparation method influences soft tissue tendon graft-bone tunnel fixation in healthy bone
Knee Surgery Sports Traumatology Arthroscopy, 2007Co-Authors: Andrew R Duffee, John Nyland, Jeffrey A Brunelli, Robert Burden, Akbar Nawab, David CabornAbstract:Bone tunnel fixation of a soft tissue tendon graft is the weak link immediately following ACL reconstruction. This biomechanical study evaluated the influence of extraction drilled or step dilated bone tunnels and Bioabsorbable Screw divergence on soft tissue tendon graft fixation. From an initial group of 50 available specimens, similar apparent bone mineral density porcine tibiae (1.2 ± 0.24 g/cm^2) were divided into two groups of ten specimens each. Group 1 (extraction drilled) received 9 mm diameter tunnels. Group 2 (step dilated) received 7 mm diameter tunnels that were dilated to 9 mm. Grafts were secured in tunnels using 10 mm diameter, 35 mm long tapered Screws. After high resolution CT scanning to evaluate Screw divergence, constructs were pretensioned on a servo hydraulic device between 10 and 50 N for 10 cycles, and isometric pretensioned at 50 N for 1 min, prior to 500 sub-maximal loading cycles (50–200 N) and load to failure testing at 20 mm/min. Wilcoxon Signed Rank tests and Mann–Whitney U -tests were used to evaluate group differences. Coefficient of determination values ( r ^2) were calculated to further delineate statistically significant relationships. Tunnel preparation method did not display statistically significant effects on insertion torque, displacement during cyclic testing, relative stiffness during cyclic testing, load at failure, stiffness during load to failure testing or displacement during load to failure testing. Screw divergence
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Bioabsorbable Screw divergence angle not tunnel preparation method influences soft tissue tendon graft bone tunnel fixation in healthy bone
Knee Surgery Sports Traumatology Arthroscopy, 2007Co-Authors: Andrew R Duffee, John Nyland, Jeffrey A Brunelli, Robert Burden, Akbar Nawab, David N M CabornAbstract:Bone tunnel fixation of a soft tissue tendon graft is the weak link immediately following ACL reconstruction. This biomechanical study evaluated the influence of extraction drilled or step dilated bone tunnels and Bioabsorbable Screw divergence on soft tissue tendon graft fixation. From an initial group of 50 available specimens, similar apparent bone mineral density porcine tibiae (1.2 ± 0.24 g/cm2) were divided into two groups of ten specimens each. Group 1 (extraction drilled) received 9 mm diameter tunnels. Group 2 (step dilated) received 7 mm diameter tunnels that were dilated to 9 mm. Grafts were secured in tunnels using 10 mm diameter, 35 mm long tapered Screws. After high resolution CT scanning to evaluate Screw divergence, constructs were pretensioned on a servo hydraulic device between 10 and 50 N for 10 cycles, and isometric pretensioned at 50 N for 1 min, prior to 500 sub-maximal loading cycles (50–200 N) and load to failure testing at 20 mm/min. Wilcoxon Signed Rank tests and Mann–Whitney U-tests were used to evaluate group differences. Coefficient of determination values (r 2) were calculated to further delineate statistically significant relationships. Tunnel preparation method did not display statistically significant effects on insertion torque, displacement during cyclic testing, relative stiffness during cyclic testing, load at failure, stiffness during load to failure testing or displacement during load to failure testing. Screw divergence < 15° produced lower displacement and greater relative stiffness during cyclic testing and greater load at failure and stiffness during load to failure testing. Screw divergence angle displayed moderate relationships with construct displacement during cyclic testing (r 2 = 0.54), stiffness during load to failure testing (r 2 = 0.60), and load at failure (r 2 = 0.41). Tunnel dilation does not enhance soft tissue tendon graft fixation strength in healthy bone. Bioabsorbable Screw divergence of ≥ 15° significantly reduces soft tissue tendon graft-bone tunnel fixation.
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soft tissue interference fixation Bioabsorbable Screw versus metal Screw
Arthroscopy, 2005Co-Authors: Jeff C Brand, John Nyland, David N M Caborn, Darren L JohnsonAbstract:Purpose: To compare the biomechanical properties of eccentrically positioned Bioabsorbable and titanium interference Screws for quadrupled hamstring tendon graft (QHTG) fixation. Type of Study: In vitro, biomechanical study. Methods: In 10 paired cadaveric tibiae and femurs (mean age, 66.5 years; range, 53 to 81 years), QHTG fixation was performed in tunnels sized to within 0.5 mm of QHTG diameter using either a titanium (RCI; Smith & Nephew Donjoy, Carlsbad, CA) or a Bioabsorbable (BioScrew; Linvatec, Largo, FL) Screw of equal size. Constructs then underwent biomechanical load-to-failure testing on a servo-hydraulic device at 20 mm/min. Results: Load at failure was greater for femoral-side QHTG fixation using the Bioabsorbable Screw than the titanium Screw (486 ± 223.7 N v 246 ± 99.1 N, P = .006); however, displacement did not differ ( P = .81). There were no statistically significant differences between groups for tibial side load at failure ( P = .54), stiffness ( P = .44), or displacement ( P = .50). Screw thread-induced graft laceration was more frequently observed in the titanium Screw group (9 of 10 grafts during femoral-side testing, 0 of 10 grafts during tibial-side testing) than in the Bioabsorbable Screw group (0 of 10 grafts during femoral-side testing, 1 of 10 grafts during tibial-side testing). Conclusions: BioScrew interference Screw fixation was comparable or superior to RCI titanium interference Screw fixation. BioScrew interference Screw fixation also produced less Screw thread-induced laceration of the QHTG during load-to-failure testing. Clinical Relevance: Use of a biodegradable interference Screw positioned directly against a soft-tisse graft provides fixation properties similar to those of a metal interference Screw.
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soft tissue tendon graft fixation in the tibial tunnel with a Bioabsorbable Screw endopearl combination in tibiae of low bone mineral density a biomechanical study
Acta Orthopaedica et Traumatologica Turcica, 2004Co-Authors: Yavuz Kocabey, John Nyland, Akbar Nawab, Erdem U Isikan, David N M CabornAbstract:Objectives: This biomechanical study evaluated soft tissue tendon graft fixation in the tibial tunnel using a Bioabsorbable interference Screw with or without supplemental EndoPearl device. Methods: Ten bovine tibiae were stripped of all soft tissues and bone tunnels 7 mm in diameter were drilled with dilation to 9 mm. Tibialis anterior allografts were fixed with a Screw (10 mm in diameter, 30 mm in length) in five tibiae of high bone mineral density (1.36 g/cm2), and with a Screw-EndoPearl combination in five tibiae of low bone mineral density (0.84 g/cm2). The specimens were cycled 10 times from 10 to 50 N, and 500 times from 50 to 200 N in a servo hydraulic test device prior to ultimate load-at-failure testing at a rate of 20 mm/min. Results: No statistically significant differences were found between the two fixation groups with respect to displacement and stiffness during cyclic testing, and with respect to load at failure, displacement, and stiffness during load-to-failure testing (p>0.05). Conclusion: The finding of similar results in both fixation groups with respect to displacement and stiffness during cyclic testing and during load-to-failure testing suggests that a Screw-EndoPearl combination in tibiae of low bone mineral density may be helpful in the prevention of graft slippage.
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quadrupled semitendinosus gracilis autograft fixation in the femoral tunnel a comparison between a metal and a Bioabsorbable interference Screw
Arthroscopy, 1998Co-Authors: David N M Caborn, John Nyland, Michael J Coen, R Neef, Doris Hamilton, Darren L JohnsonAbstract:Abstract Although semitendinosus-gracilis (SG) grafts for anterior cruciate ligament reconstruction have many potential benefits, effective fixation remains a challenge. This study assessed differences between the maximum pullout forces needed to detach a quadrupled SG graft from a femoral tunnel when secured by either a metal or a Bioabsorbable interference Screw. Sixteen paired fresh frozen quadrupled SG autografts (x, 8.4 mm; range, 7-10 mm) from 8 donors were anchored into cadaveric femoral tunnels by either a 7-mm metal or a 7-mm Bioabsorbable Screw after bone mineral density (BMD) assessment and before undergoing a longitudinal 20 mm/min traction force. Statistical analysis compared BMD (gm/cm2), insertional torque (N-m), and maximum load at pullout (N) between Screw types. Insertional torques (.28-1.21, N-m range) did not correlate ( P >.05) to BMD or maximum load at pullout (x ± S.D.) 242 ± 90.7 N (metal Screw) and 341.1 ± 162.9 N (Bioabsorbable Screw). Differences did not exist between the maximum load at pullout for Bioabsorbable or metal Screw fixation ( P = .16). Careful graft preparation, sizing, and matched tunnel placement enables interference fit and fixation capable of reliably withstanding the low- level rehabilitation loads to which the graft is exposed until bony ingrowth occurs. Arthroscopy 1998 Apr;14(3):241-5
Akbar Nawab - One of the best experts on this subject based on the ideXlab platform.
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Bioabsorbable Screw divergence angle not tunnel preparation method influences soft tissue tendon graft bone tunnel fixation in healthy bone
Knee Surgery Sports Traumatology Arthroscopy, 2007Co-Authors: Andrew R Duffee, John Nyland, Jeffrey A Brunelli, Robert Burden, Akbar Nawab, David N M CabornAbstract:Bone tunnel fixation of a soft tissue tendon graft is the weak link immediately following ACL reconstruction. This biomechanical study evaluated the influence of extraction drilled or step dilated bone tunnels and Bioabsorbable Screw divergence on soft tissue tendon graft fixation. From an initial group of 50 available specimens, similar apparent bone mineral density porcine tibiae (1.2 ± 0.24 g/cm2) were divided into two groups of ten specimens each. Group 1 (extraction drilled) received 9 mm diameter tunnels. Group 2 (step dilated) received 7 mm diameter tunnels that were dilated to 9 mm. Grafts were secured in tunnels using 10 mm diameter, 35 mm long tapered Screws. After high resolution CT scanning to evaluate Screw divergence, constructs were pretensioned on a servo hydraulic device between 10 and 50 N for 10 cycles, and isometric pretensioned at 50 N for 1 min, prior to 500 sub-maximal loading cycles (50–200 N) and load to failure testing at 20 mm/min. Wilcoxon Signed Rank tests and Mann–Whitney U-tests were used to evaluate group differences. Coefficient of determination values (r 2) were calculated to further delineate statistically significant relationships. Tunnel preparation method did not display statistically significant effects on insertion torque, displacement during cyclic testing, relative stiffness during cyclic testing, load at failure, stiffness during load to failure testing or displacement during load to failure testing. Screw divergence < 15° produced lower displacement and greater relative stiffness during cyclic testing and greater load at failure and stiffness during load to failure testing. Screw divergence angle displayed moderate relationships with construct displacement during cyclic testing (r 2 = 0.54), stiffness during load to failure testing (r 2 = 0.60), and load at failure (r 2 = 0.41). Tunnel dilation does not enhance soft tissue tendon graft fixation strength in healthy bone. Bioabsorbable Screw divergence of ≥ 15° significantly reduces soft tissue tendon graft-bone tunnel fixation.
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Bioabsorbable Screw divergence angle, not tunnel preparation method influences soft tissue tendon graft-bone tunnel fixation in healthy bone
Knee Surgery Sports Traumatology Arthroscopy, 2007Co-Authors: Andrew R Duffee, John Nyland, Jeffrey A Brunelli, Robert Burden, Akbar Nawab, David CabornAbstract:Bone tunnel fixation of a soft tissue tendon graft is the weak link immediately following ACL reconstruction. This biomechanical study evaluated the influence of extraction drilled or step dilated bone tunnels and Bioabsorbable Screw divergence on soft tissue tendon graft fixation. From an initial group of 50 available specimens, similar apparent bone mineral density porcine tibiae (1.2 ± 0.24 g/cm^2) were divided into two groups of ten specimens each. Group 1 (extraction drilled) received 9 mm diameter tunnels. Group 2 (step dilated) received 7 mm diameter tunnels that were dilated to 9 mm. Grafts were secured in tunnels using 10 mm diameter, 35 mm long tapered Screws. After high resolution CT scanning to evaluate Screw divergence, constructs were pretensioned on a servo hydraulic device between 10 and 50 N for 10 cycles, and isometric pretensioned at 50 N for 1 min, prior to 500 sub-maximal loading cycles (50–200 N) and load to failure testing at 20 mm/min. Wilcoxon Signed Rank tests and Mann–Whitney U -tests were used to evaluate group differences. Coefficient of determination values ( r ^2) were calculated to further delineate statistically significant relationships. Tunnel preparation method did not display statistically significant effects on insertion torque, displacement during cyclic testing, relative stiffness during cyclic testing, load at failure, stiffness during load to failure testing or displacement during load to failure testing. Screw divergence
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soft tissue tendon graft fixation in the tibial tunnel with a Bioabsorbable Screw endopearl combination in tibiae of low bone mineral density a biomechanical study
Acta Orthopaedica et Traumatologica Turcica, 2004Co-Authors: Yavuz Kocabey, John Nyland, Akbar Nawab, Erdem U Isikan, David N M CabornAbstract:Objectives: This biomechanical study evaluated soft tissue tendon graft fixation in the tibial tunnel using a Bioabsorbable interference Screw with or without supplemental EndoPearl device. Methods: Ten bovine tibiae were stripped of all soft tissues and bone tunnels 7 mm in diameter were drilled with dilation to 9 mm. Tibialis anterior allografts were fixed with a Screw (10 mm in diameter, 30 mm in length) in five tibiae of high bone mineral density (1.36 g/cm2), and with a Screw-EndoPearl combination in five tibiae of low bone mineral density (0.84 g/cm2). The specimens were cycled 10 times from 10 to 50 N, and 500 times from 50 to 200 N in a servo hydraulic test device prior to ultimate load-at-failure testing at a rate of 20 mm/min. Results: No statistically significant differences were found between the two fixation groups with respect to displacement and stiffness during cyclic testing, and with respect to load at failure, displacement, and stiffness during load-to-failure testing (p>0.05). Conclusion: The finding of similar results in both fixation groups with respect to displacement and stiffness during cyclic testing and during load-to-failure testing suggests that a Screw-EndoPearl combination in tibiae of low bone mineral density may be helpful in the prevention of graft slippage.
