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Tsutomu Takizawa - One of the best experts on this subject based on the ideXlab platform.

  • Fixation of the nexgen ha tcp coated cementless screwless total knee arthroplasty comparison with conventional cementless total knee arthroplasty of the same type
    Journal of Arthroplasty, 2002
    Co-Authors: Ryuichi Gejo, Shaw Akizuki, Tsutomu Takizawa
    Abstract:

    We performed a 12-month prospective study on 59 patients (92 knees) who underwent NexGen (Zimmer Inc, Warsaw, IN) cruciate-retaining total knee arthroplasty. In the control group, uncoated components were fixed using screws, whereas the hydroxyapatite-tricalcium phosphate (HA-TCP) group underwent screwless Fixation of coated components. At 12 months postoperatively, there was a radiographic clear zone around the femoral and tibial components of 56.5% and 32.6% of the knees in the control group. The HA-TCP group showed a clear zone at the medial aspect of the tibial component in only 1 knee. These results suggested that HA-TCP-coated articular components show good Initial Fixation without using screws. The NexGen coated knee arthroplasty may be useful for solving the problems of cementless Fixation.

  • Fixation of the nexgen ha tcp coated cementless screwless total knee arthroplasty comparison with conventional cementless total knee arthroplasty of the same type
    Journal of Arthroplasty, 2002
    Co-Authors: Ryuichi Gejo, Shaw Akizuki, Tsutomu Takizawa
    Abstract:

    Abstract We performed a 12-month prospective study on 59 patients (92 knees) who underwent NexGen (Zimmer Inc, Warsaw, IN) cruciate-retaining total knee arthroplasty. In the control group, uncoated components were fixed using screws, whereas the hydroxyapatite–tricalcium phosphate (HA-TCP) group underwent screwless Fixation of coated components. At 12 months postoperatively, there was a radiographic clear zone around the femoral and tibial components of 56.5% and 32.6% of the knees in the control group. The HA-TCP group showed a clear zone at the medial aspect of the tibial component in only 1 knee. These results suggested that HA-TCP-coated articular components show good Initial Fixation without using screws. The NexGen coated knee arthroplasty may be useful for solving the problems of cementless Fixation. Copyright 2002, Elsevier Science (USA). All rights reserved.

Teppo L N Jarvinen - One of the best experts on this subject based on the ideXlab platform.

  • bone density and insertion torque as predictors of anterior cruciate ligament graft Fixation strength
    American Journal of Sports Medicine, 2004
    Co-Authors: Teppo L N Jarvinen, Janne T Nurmi, Harri Sievanen
    Abstract:

    Background: Bone mineral density and interference screw insertion torque are thought to be useful predictors of anterior cruciate ligament graft Fixation strength.Hypothesis: Bone mineral density and insertion torque are reliable predictors of anterior cruciate ligament graft Fixation strength.Study Design: Randomized experimental study.Methods: The volumetric bone mineral density, maximum insertion torque, and Initial Fixation strength (determined both as cyclic-loading-induced displacement and yield load) were recorded on 21 pairs of anterior cruciate ligament reconstructions. To assess the accuracy of bone mineral density and insertion torque in predicting the Fixation strength, half of the specimens were first used to determine the regression equations between the variables, and then the data from the remaining specimens were used to validate the prediction equations.Results: Despite the relatively high group correlations, the ability of bone mineral density and insertion torque to predict the strengt...

  • interference screw Fixation of soft tissue grafts in anterior cruciate ligament reconstruction part 1 effect of tunnel compaction by serial dilators versus extraction drilling on the Initial Fixation strength
    American Journal of Sports Medicine, 2004
    Co-Authors: Janne T Nurmi, Markku Järvinen, Pekka Kannus, Harri Sievanen, Timo Jarvela, Teppo L N Jarvinen
    Abstract:

    BackgroundCompaction of the bone-tunnel walls by serial dilation is believed to enhance the interference screw Fixation strength of the soft tissue grafts in anterior cruciate ligament (ACL) reconstruction.HypothesisSerial dilation enhances the Fixation strength of soft tissue grafts in ACL reconstruction over extraction drilling.Study DesignRandomized experimental study.MethodsInitial Fixation strength of the doubled anterior tibialis tendon grafts (fixed with a bioabsorbable interference screw) was assessed in 21 pairs of human cadaver tibiae with either serially dilated or extraction-drilled bone tunnels. The specimens were subjected to a cyclic-loading test, and those surviving were then tested using the single-cycle load-to-failure test.ResultsDuring the cyclic-loading test, there were 3 Fixation failures in the serially dilated and 6 failures in the extraction-drilled specimens but no significant stiffness or displacement differences between the groups. In the subsequent load-to-failure test, the av...

  • the Fixation strength of six hamstring tendon graft Fixation devices in anterior cruciate ligament reconstruction part i femoral site
    American Journal of Sports Medicine, 2003
    Co-Authors: Petteri Kousa, Mika Vihavainen, Teppo L N Jarvinen, Markku Järvinen
    Abstract:

    Background:Strength of graft Fixation is the weakest link in anterior cruciate ligament reconstruction.Hypothesis:There is no difference in Initial Fixation strength between different hamstring tendon graft femoral Fixation devices.Study Design:Randomized experimental study.Methods:Each of six devices was used in the Fixation of 10 quadrupled human semitendinosus-gracilis tendon grafts in tunnels drilled in porcine femora and tested 10 times with a single-cycle load-to-failure test at a rate of 50 mm/min and 10 times with a 1500-cycle loading test between 50 and 200 N at one cycle every 2 seconds. The specimens that survived the cyclic loading were subjected to a single-cycle load-to-failure test.Results:The Bone Mulch Screw (1112 N) was strongest in the single-cycle load-to-failure test, followed by EndoButton CL (1086 N), RigidFix (868 N), SmartScrew ACL (794 N), BioScrew (589 N), and RCI screw (546 N). It also showed the lowest residual displacement (2.2 mm) and was strongest in the single-cycle load-t...

  • Initial Fixation strength of bioabsorbable and titanium interference screws in anterior cruciate ligament reconstruction biomechanical evaluation by single cycle and cyclic loading
    American Journal of Sports Medicine, 2001
    Co-Authors: Petteri Kousa, Teppo L N Jarvinen, Pekka Kannus, Markku Järvinen
    Abstract:

    We evaluated the Initial bone-patellar tendon-bone graft Fixation strength of bioabsorbable as compared with titanium interference screws in anterior cruciate ligament reconstruction using matched pairs of porcine knees. Ten pairs underwent single-cycle failure loading at a rate of 50 mm/min, and 10 pairs underwent cyclic loading at half-hertz frequency. The cyclic loading started with 100 load cycles between 50 and 150 N. We then progressively increased loads in 50-N increments after each set of 100 cycles. After 100 cycles at 850 N, the specimens were loaded to failure at a rate of 50 mm/min. In the single-cycle failure loading test, the mean ultimate failure loads (+/-SD) for the bioabsorbable (837 +/- 260 N) and titanium interference screws (863 +/- 192 N) were not significantly different, nor were the mean yield loads or the stiffness of the Fixation. In the cyclic loading test, the yield loads were 605 +/- 142 N and 585 +/- 103 N for the bioabsorbable and titanium interference screws, respectively (no significant difference). Although there was no significant difference in the ultimate failure load, more bone block fractures were found in the grafts fixed with a titanium interference screw. Bioabsorbable interference screw Fixation thus seems to provide a reasonable alternative to titanium screws.

Ryuichi Gejo - One of the best experts on this subject based on the ideXlab platform.

  • Fixation of the nexgen ha tcp coated cementless screwless total knee arthroplasty comparison with conventional cementless total knee arthroplasty of the same type
    Journal of Arthroplasty, 2002
    Co-Authors: Ryuichi Gejo, Shaw Akizuki, Tsutomu Takizawa
    Abstract:

    We performed a 12-month prospective study on 59 patients (92 knees) who underwent NexGen (Zimmer Inc, Warsaw, IN) cruciate-retaining total knee arthroplasty. In the control group, uncoated components were fixed using screws, whereas the hydroxyapatite-tricalcium phosphate (HA-TCP) group underwent screwless Fixation of coated components. At 12 months postoperatively, there was a radiographic clear zone around the femoral and tibial components of 56.5% and 32.6% of the knees in the control group. The HA-TCP group showed a clear zone at the medial aspect of the tibial component in only 1 knee. These results suggested that HA-TCP-coated articular components show good Initial Fixation without using screws. The NexGen coated knee arthroplasty may be useful for solving the problems of cementless Fixation.

  • Fixation of the nexgen ha tcp coated cementless screwless total knee arthroplasty comparison with conventional cementless total knee arthroplasty of the same type
    Journal of Arthroplasty, 2002
    Co-Authors: Ryuichi Gejo, Shaw Akizuki, Tsutomu Takizawa
    Abstract:

    Abstract We performed a 12-month prospective study on 59 patients (92 knees) who underwent NexGen (Zimmer Inc, Warsaw, IN) cruciate-retaining total knee arthroplasty. In the control group, uncoated components were fixed using screws, whereas the hydroxyapatite–tricalcium phosphate (HA-TCP) group underwent screwless Fixation of coated components. At 12 months postoperatively, there was a radiographic clear zone around the femoral and tibial components of 56.5% and 32.6% of the knees in the control group. The HA-TCP group showed a clear zone at the medial aspect of the tibial component in only 1 knee. These results suggested that HA-TCP-coated articular components show good Initial Fixation without using screws. The NexGen coated knee arthroplasty may be useful for solving the problems of cementless Fixation. Copyright 2002, Elsevier Science (USA). All rights reserved.

Markku Järvinen - One of the best experts on this subject based on the ideXlab platform.

  • interference screw Fixation of soft tissue grafts in anterior cruciate ligament reconstruction part 1 effect of tunnel compaction by serial dilators versus extraction drilling on the Initial Fixation strength
    American Journal of Sports Medicine, 2004
    Co-Authors: Janne T Nurmi, Markku Järvinen, Pekka Kannus, Harri Sievanen, Timo Jarvela, Teppo L N Jarvinen
    Abstract:

    BackgroundCompaction of the bone-tunnel walls by serial dilation is believed to enhance the interference screw Fixation strength of the soft tissue grafts in anterior cruciate ligament (ACL) reconstruction.HypothesisSerial dilation enhances the Fixation strength of soft tissue grafts in ACL reconstruction over extraction drilling.Study DesignRandomized experimental study.MethodsInitial Fixation strength of the doubled anterior tibialis tendon grafts (fixed with a bioabsorbable interference screw) was assessed in 21 pairs of human cadaver tibiae with either serially dilated or extraction-drilled bone tunnels. The specimens were subjected to a cyclic-loading test, and those surviving were then tested using the single-cycle load-to-failure test.ResultsDuring the cyclic-loading test, there were 3 Fixation failures in the serially dilated and 6 failures in the extraction-drilled specimens but no significant stiffness or displacement differences between the groups. In the subsequent load-to-failure test, the av...

  • the Fixation strength of six hamstring tendon graft Fixation devices in anterior cruciate ligament reconstruction part i femoral site
    American Journal of Sports Medicine, 2003
    Co-Authors: Petteri Kousa, Mika Vihavainen, Teppo L N Jarvinen, Markku Järvinen
    Abstract:

    Background:Strength of graft Fixation is the weakest link in anterior cruciate ligament reconstruction.Hypothesis:There is no difference in Initial Fixation strength between different hamstring tendon graft femoral Fixation devices.Study Design:Randomized experimental study.Methods:Each of six devices was used in the Fixation of 10 quadrupled human semitendinosus-gracilis tendon grafts in tunnels drilled in porcine femora and tested 10 times with a single-cycle load-to-failure test at a rate of 50 mm/min and 10 times with a 1500-cycle loading test between 50 and 200 N at one cycle every 2 seconds. The specimens that survived the cyclic loading were subjected to a single-cycle load-to-failure test.Results:The Bone Mulch Screw (1112 N) was strongest in the single-cycle load-to-failure test, followed by EndoButton CL (1086 N), RigidFix (868 N), SmartScrew ACL (794 N), BioScrew (589 N), and RCI screw (546 N). It also showed the lowest residual displacement (2.2 mm) and was strongest in the single-cycle load-t...

  • Initial Fixation strength of bioabsorbable and titanium interference screws in anterior cruciate ligament reconstruction biomechanical evaluation by single cycle and cyclic loading
    American Journal of Sports Medicine, 2001
    Co-Authors: Petteri Kousa, Teppo L N Jarvinen, Pekka Kannus, Markku Järvinen
    Abstract:

    We evaluated the Initial bone-patellar tendon-bone graft Fixation strength of bioabsorbable as compared with titanium interference screws in anterior cruciate ligament reconstruction using matched pairs of porcine knees. Ten pairs underwent single-cycle failure loading at a rate of 50 mm/min, and 10 pairs underwent cyclic loading at half-hertz frequency. The cyclic loading started with 100 load cycles between 50 and 150 N. We then progressively increased loads in 50-N increments after each set of 100 cycles. After 100 cycles at 850 N, the specimens were loaded to failure at a rate of 50 mm/min. In the single-cycle failure loading test, the mean ultimate failure loads (+/-SD) for the bioabsorbable (837 +/- 260 N) and titanium interference screws (863 +/- 192 N) were not significantly different, nor were the mean yield loads or the stiffness of the Fixation. In the cyclic loading test, the yield loads were 605 +/- 142 N and 585 +/- 103 N for the bioabsorbable and titanium interference screws, respectively (no significant difference). Although there was no significant difference in the ultimate failure load, more bone block fractures were found in the grafts fixed with a titanium interference screw. Bioabsorbable interference screw Fixation thus seems to provide a reasonable alternative to titanium screws.

Shaw Akizuki - One of the best experts on this subject based on the ideXlab platform.

  • Fixation of the nexgen ha tcp coated cementless screwless total knee arthroplasty comparison with conventional cementless total knee arthroplasty of the same type
    Journal of Arthroplasty, 2002
    Co-Authors: Ryuichi Gejo, Shaw Akizuki, Tsutomu Takizawa
    Abstract:

    We performed a 12-month prospective study on 59 patients (92 knees) who underwent NexGen (Zimmer Inc, Warsaw, IN) cruciate-retaining total knee arthroplasty. In the control group, uncoated components were fixed using screws, whereas the hydroxyapatite-tricalcium phosphate (HA-TCP) group underwent screwless Fixation of coated components. At 12 months postoperatively, there was a radiographic clear zone around the femoral and tibial components of 56.5% and 32.6% of the knees in the control group. The HA-TCP group showed a clear zone at the medial aspect of the tibial component in only 1 knee. These results suggested that HA-TCP-coated articular components show good Initial Fixation without using screws. The NexGen coated knee arthroplasty may be useful for solving the problems of cementless Fixation.

  • Fixation of the nexgen ha tcp coated cementless screwless total knee arthroplasty comparison with conventional cementless total knee arthroplasty of the same type
    Journal of Arthroplasty, 2002
    Co-Authors: Ryuichi Gejo, Shaw Akizuki, Tsutomu Takizawa
    Abstract:

    Abstract We performed a 12-month prospective study on 59 patients (92 knees) who underwent NexGen (Zimmer Inc, Warsaw, IN) cruciate-retaining total knee arthroplasty. In the control group, uncoated components were fixed using screws, whereas the hydroxyapatite–tricalcium phosphate (HA-TCP) group underwent screwless Fixation of coated components. At 12 months postoperatively, there was a radiographic clear zone around the femoral and tibial components of 56.5% and 32.6% of the knees in the control group. The HA-TCP group showed a clear zone at the medial aspect of the tibial component in only 1 knee. These results suggested that HA-TCP-coated articular components show good Initial Fixation without using screws. The NexGen coated knee arthroplasty may be useful for solving the problems of cementless Fixation. Copyright 2002, Elsevier Science (USA). All rights reserved.