Research Topics
| Andrew Todd MaharSummaryAffiliation: Children's Hospital and Health Center Country: USA Publications
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Detail Information
Publications
Increasing the insertion depth of suture anchors for rotator cuff repair does not improve biomechanical stabilityAndrew T Mahar
Orthopedic Biomechanics Research Center, Children s Hospital, 3020 Children s Way, San Diego, CA 92123, USA
J Shoulder Elbow Surg 14:626-30. 2005..Cyclic testing showed significant displacement, regardless of anchor position, possibly leading to gap formation of the repair. Deep placement of suture anchors for increased purchase caused greater displacement and is not recommended...- Single-row suture anchor repair of the rotator cuff is biomechanically equivalent to double-row repair in a bovine modelAndrew Mahar
Department of Orthopaedic Surgery, University of California, San Diego, California, USA
Arthroscopy 23:1265-70. 2007..The purpose of this study was to determine biomechanical differences in cyclic elongation and ultimate strength between double-row rotator cuff repair and single-row repair for partial rotator cuff repairs... - A biomechanical and radiographic analysis of standard and intracortical suture anchors for arthroscopic rotator cuff repairAndrew Mahar
Orthopedic Biomechanics Research Center, Children s Hospital, San Diego, California, USA
Arthroscopy 22:130-5. 2006..To compare the fixation strength and radiographic motion of an anchor designed for intracortical (IC) fixation (FT Anchor, Arthrex, Naples, FL) with that of standard anchors used for rotator cuff repair... - Biomechanical comparison of different anchors (foundations) for the pediatric dual growing rod techniqueAndrew Todd Mahar
Department of Orthopedics, Rady Children s Hospital San Diego, San Diego, CA, USA
Spine J 8:933-9. 2008..The foundations that provide anchor points for the dual growing rods may incorporate hooks, screws, or a hybrid construct. It is unclear how stable different types of foundation constructs are with regard to pullout... - Comparison and performance characteristics of 3 different knots when tied with 2 suture materials used for shoulder arthroscopyAndrew T Mahar
Department of Orthopaedic Surgery, University of California San Diego, San Diego, California, USA
Arthroscopy 22:614.e1-2. 2006..To compare the performance of a standard suture material with that of a new material across several arthroscopic knot configurations... - A biomechanical analysis of a novel arthroscopic suture method compared to standard suture knots and materials for rotator cuff repairAndrew Mahar
Department of Orthopaedics, Children s Hospital, San Diego, California 92123, USA
Arthroscopy 23:1162-6. 2007..To biomechanically compare a novel suture welding method to 2 standard suture materials when tied with 3 types of arthroscopic knots... - Biomechanical comparison of stainless steel and titanium nails for fixation of simulated femoral fracturesAndrew T Mahar
Orthopedic Biomechanics Research Center, Department of Orthopedics, Children s Hospital, San Diego, San Diego, California 92123, USA
J Pediatr Orthop 24:638-41. 2004..Both materials stabilized simulated fractures at levels beyond physiologic non-weight-bearing loads without permanent deformation... - Biomechanical comparison of four different fixation techniques for pediatric tibial eminence avulsion fracturesAndrew T Mahar
Department of Orthopedic Surgery, Rady Children s Hospital San Diego, 3020 Children s Way, San Diego, CA 92123, USA
J Pediatr Orthop 28:159-62. 2008..The purpose of this study was to compare the biomechanical stability of tibial eminence avulsion fractures using suture, resorbable screw, resorbable nail, and metal screw techniques... - Differences in biomechanical stability of femur fracture fixation when using titanium nails of increasing diameterAndrew Mahar
Orthopedic Biomechanics Research Center, Department of Orthopedics, Rady Children s Hospital, San Diego, MC5054, 3020 Children s Way, San Diego, CA, 92123, USA
J Child Orthop 1:211-5. 2007..The purpose of this study was to compare the biomechanical stability generated when utilizing increasing sizes of titanium (Ti) flexible nails for fixation of simulated comminuted femur fractures... - Short-segment fixation of lumbar burst fractures using pedicle fixation at the level of the fractureAndrew Mahar
Department of Orthopedic Surgery, University of California San Diego, San Diego, CA, USA
Spine (Phila Pa 1976) 32:1503-7. 2007..Cadaveric biomechanical study and retrospective chart review... - Biomechanics of cantilever "plow" during anterior thoracic scoliosis correctionAndrew T Mahar
Children s Hospital, San Diego, MC5054, 3020 Children s Way, San Diego, CA 92123, USA
Spine J 6:572-6. 2006..Loss of spinal correction may occur after failure at the bone-implant interface, and forces on the bone-implant interface during scoliosis correction remain unclear... - Biomechanical comparison of a novel percutaneous transfacet device and a traditional posterior system for single level fusionAndrew Mahar
Department of Orthopaedic Surgery, University of California, San Diego, CA, USA
J Spinal Disord Tech 19:591-4. 2006..The length adjustability of the device may alleviate concerns for precise device placement and the biomechanical stability may produce similar rates and quality of posterior spinal fusions... - Biomechanical evaluation of a new technique for rotator cuff repairCharles J Petit
Orthopaedic Biomechanics Research Center, Children's Hospital, San Diego, California, USA
Am J Sports Med 31:849-53. 2003..Clinical Relevance: This is a time-zero study of implant performance. The results indicate that the implant may decrease clinical failures in the early postoperative period under standard rehabilitation protocols... - Biomechanical comparison of bioabsorbable sutureless screw anchor versus suture anchor fixation for rotator cuff repairSteve Lee
Department of Orthopaedics, University of California San Diego, San Diego, California, USA
Arthroscopy 21:43-7. 2005..CLINICAL RELEVANCE: This bioabsorbable anchor may not provide sufficient fixation for rotator cuff repair in humans... - Unilateral and bilateral sacropelvic fixation result in similar construct biomechanicsTucker Tomlinson
Orthopedic Biomechanics Research Center, Department of Orthopedics, Rady Children s Hospital San Diego, San Diego, CA 92123, USA
Spine (Phila Pa 1976) 33:2127-33. 2008..In vitro biomechanical investigation of lumbosacropelvic spinal instrumentation... - Biomechanical comparison of fully and partially threaded screws for fixation of slipped capital femoral epiphysisFiroz Miyanji
Department of Orthopedics, Rady Children s Hospital, University of California, San Diego, CA, USA
J Pediatr Orthop 28:49-52. 2008..The purpose of the current study was to determine if a fully threaded cancellous screw provides greater stability compared with a partially threaded screw in a porcine model... - Biomechanical comparison of the screw-bone interface: optimization of 1 and 2 screw constructs by varying screw diameterFazir Mohamad
Department of Orthopedic Surgery, Children's Hospital, San Diego, CA, USA
Spine 31:E535-9. 2006..CONCLUSIONS: Failure modes for 1-screw constructs almost entirely (89%) showed gradual plowing through the bone, whereas acute fracture through the vertebral body or pedicles were common forms of failure (85%) for 2-screw constructs... - Biomechanical stability of single-screw versus two-screw fixation of an unstable slipped capital femoral epiphysis model: effect of screw position in the femoral neckShyam Kishan
Department of Orthopaedics, Children's Hospital, San Diego, CA, USA
J Pediatr Orthop 26:601-5. 2006..The biomechanical benefit of 2 screws needs to be considered in the face of greater potential for inadvertent penetration into the joint with an increased number of screws... - The mechanical properties of the ligamentum teres: a pilot study to assess its potential for improving stability in children's hip surgeryDennis Wenger
Department of Orthopedics, Rady Children s Hospital San Diego, CA 92123, USA
J Pediatr Orthop 27:408-10. 2007..In the setting of dysplasia, the preservation and the transfer of the ligamentum teres to augment stability should be considered as an adjunct to open reduction... - Residual motion on flexion-extension radiographs after simulated lumbar arthrodesis in human cadaversChristopher M Bono
Department of Orthopaedic Surgery, Harvard Medical School, Brigham and Women s Hospital, Boston, MA 02115, USA
J Spinal Disord Tech 21:364-71. 2008..However, as the degrees of motion seemed to be high, future studies should use a fusion simulation other than metallic implants that more closely resembles bony arthrodesis... - Biomechanical analysis of single screw fixation for slipped capital femoral epiphysis: are more threads across the physis necessary for stability?Vidyadhar Upasani
Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, USA
J Pediatr Orthop 26:474-8. 2006..To evaluate single screw fixation stability, in the treatment of slipped capital femoral epiphysis, as a function of screw thread distribution across the physis... - Biomechanical comparison of lumbosacral fixation using Luque-Galveston and Colorado II sacropelvic fixation: advantage of using locked proximal fixationSean Early
Division of Orthopaedic Surgery, Children's Hospital-Los Angeles, Los Angeles, CA, USA
Spine 30:1396-401. 2005..The addition of a pair of L1 pedicle screws increased the construct stiffness for both constructs by approximately 50%... - Titanium versus stainless steel for anterior spinal fusions: an analysis of rod stress as a predictor of rod breakage during physiologic loading in a bovine modelMichelle Wedemeyer
Department of Orthopedics, Children s Hospital, San Diego, San Diego, CA, USA
Spine (Phila Pa 1976) 32:42-8. 2007..In vitro biomechanical evaluation of rod stress during physiologic loading of anterior scoliosis instrumentation... - Biomechanical and radiographic analysis of a novel, minimally invasive, extension-limiting device for the lumbar spineSylvain Palmer
Mission Hospital and Regional Medical Center, University of California, Irvine, California, USA
Neurosurg Focus 22:E4. 2007..It is a titanium screw-based system with a polycarbonate-urethane bumper that lies against the inferior articular process and is anchored into the pedicle by the screw for posterior dynamic stabilization (PDS)... - Biomechanical comparison of two different periarticular plating systems for stabilization of complex distal humerus fracturesAlexandra Schwartz
Department of Orthopaedic Surgery, University of California, San Diego, San Diego, CA 92123-4282, United States
Clin Biomech (Bristol, Avon) 21:950-5. 2006..Plate strain differences may affect fragment position, but it is unclear how much plate loading occurs in vivo. Surgeon experience and preference may dictate the choice of a plate construct for this fracture configuration... - A biomechanical evaluation of three surgical techniques for subscapularis repairGregory R Van den Berghe
Shiley Center for Orthopaedic Research and Education at Scripps Clinic, La Jolla, CA, USA
J Shoulder Elbow Surg 17:156-61. 2008..The bone-to-bone repair exhibited the best combination of repair strength and restoration of subscapularis length... - Biomechanical analysis of femoral tunnel pull-out angles for anterior cruciate ligament reconstruction with bioabsorbable and metal interference screwsAlan L Zhang
Department of Orthopaedic Surgery, University of California at San Diego, California, USA
Am J Sports Med 35:637-42. 2007..Fixation strength of metal and bioabsorbable interference screws has not been evaluated while varying the anterior cruciate ligament graft tension angle... - Biomechanical evaluation of clavicle fracture plating techniques: does a locking plate provide improved stability?Paul Celestre
Department of Orthopaedic Surgery, University of California San Diego, San Diego, California, USA
J Orthop Trauma 22:241-7. 2008..5 mm Universal Locking System Contourable Dual Compression Plate (Locked CDCP) in a synthetic midshaft transverse clavicle fracture model... - Biomechanical evaluation of an injectable radiopaque polypropylene fumarate cement for kyphoplasty in a cadaveric osteoporotic vertebral compression fracture modelCholl Kim
Department of Orthopaedic Surgery, University of California, San Diego, CA, USA
J Spinal Disord Tech 20:604-9. 2007..The biopolymer PPF-30 exhibits mechanical properties similar to PMMA in a cadaveric kyphoplasty model. PPF biopolymer may be a suitable alternative for kyphoplasty... - Biomechanical evaluation of kyphoplasty with calcium sulfate cement in a cadaveric osteoporotic vertebral compression fracture modelAndrew Perry
Veterans Administration and University of California, San Diego, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
Spine J 5:489-93. 2005..It may be a useful alternative bone cement for kyphoplasty. Further studies are required to assess the bioabsorption of CSCs after kyphoplasty in vivo... - Abductor length alterations in hips with SCFE deformityRyan C Goodwin
Department of Orthopaedic Surgery, The Cleveland Clinic Foundation, Cleveland, OH, USA
Clin Orthop Relat Res 454:163-8. 2007..The femoral neck base osteotomy restored the hip abductor relationship better than an osteotomy performed below the greater trochanter. We did not address the question of whether this improved relationship directly influenced function... - Evaluation of 5 knots and 2 suture materials for arthroscopic rotator cuff repair: very strong sutures can still slipGaurav Abbi
Department of Orthopaedic Surgery, University of California San Diego, San Diego, California, USA
Arthroscopy 22:38-43. 2006..CLINICAL RELEVANCE: Surgeons should understand the impact of handling characteristics, frictional properties, and ultimate failure load when selecting suture materials and knots for arthroscopic repair... - Mechanical and structural characteristics of the new BONE-LOK cortical-cancellous internal fixation deviceVictor V Cachia
Aestheticare Podiatric Surgical Residency Program, San Juan Capistrano, California, USA
J Foot Ankle Surg 42:15-20. 2003..7-mm helical compression anchor as compared with the 3.0-mm titanium cancellous screws in these testing models. This difference represents a distinct advantage in the new device that warrants further in vivo testing... - A computational evaluation of the effect of intramedullary nail material properties on the stabilization of simulated femoral shaft fracturesAngel Perez
Department of Mechanical Engineering and Computational Sciences Research Center, San Diego State University, and Department of Orthopedics, Rady Children s Hospital San Diego, San Diego, CA 92182 1323, USA
Med Eng Phys 30:755-60. 2008..Additionally, stainless steel nails had higher curve apex von Mises stresses, potentially inducing a stress-shielding effect which could hamper remodeling and consequently increase risk of re-fracture... - A comparison of the fixation stability of multiple screw constructs for two types of pelvic osteotomiesWalid Yassir
Orthopedic Biomechanics Research Center, Children's Hospital San Diego, California, USA
J Pediatr Orthop 25:14-7. 2005..Because the Ganz procedure violates the triradiate cartilage, it is not feasible in the immature patient. Thus, an understanding of fixation requirements in other available osteotomies to maintain fragment position is necessary... - Intramedullary flexible nail fixation of unstable pediatric tibial diaphyseal fracturesRyan C Goodwin
Department of Orthopedics, The Cleveland Clinic Foundation, Cleveland, OH, USA
J Pediatr Orthop 25:570-6. 2005..While the C and S construct was superior in biomechanical testing, the double C construct is more reliable and straightforward and remains by far the authors' preferred technique... - Freedom of acetabular fragment rotation following three surgical techniques for correction of congenital deformities of the hipAfshin Aminian
Orthopedic Biomechanics Research Center, Children's Hospital San Diego, California, USA
J Pediatr Orthop 25:10-3. 2005..The Tonnis osteotomy allowed freedom of motion similar to the Ganz osteotomy without coupled motion... - Biomechanical analysis of anterior instrumentation for lumbar corpectomyFrances D Faro
University of California San Diego, San Diego, USA
Spine 28:E468-71. 2003..Both systems provided secure initial fixation following lumbar corpectomy; however, the Antares system may increase the likelihood of graft incorporation in cases with greater instability and higher load demands... - Displaced olecranon fractures in children: a biomechanical analysis of fixation methodsStefan Parent
Hospital St Justine, Montreal, Quebec, Canada
J Pediatr Orthop 28:147-51. 2008.... - Spinal growth modulation with an anterolateral flexible tether in an immature bovine model: disc health and motion preservationPeter O Newton
Rady Children s Hospital, San Diego, Children s Way, San Diego, California 92123, USA
Spine (Phila Pa 1976) 33:724-33. 2008..An immature bovine model was used to evaluate multilevel anterolateral flexible tethering in a growing spine... - Biomechanical evaluation of retrograde intramedullary stabilization for femoral fractures: the effect of fracture levelRyan Goodwin
Department of Orthopedic Surgery, The Cleveland Clinic Foundation, Cleveland, OH, USA
J Pediatr Orthop 27:873-6. 2007..The purpose of this study was to evaluate the biomechanical stability of retrograde and antegrade nailing for mid-diaphyseal and distal diaphysis femoral fractures... - Screw head impingement after in situ fixation in moderate and severe slipped capital femoral epiphysisRyan C Goodwin
Department of Orthopaedic Surgery, The Cleveland Clinic Foundation, Cleveland, OH, USA
J Pediatr Orthop 27:319-25. 2007..Alternative in situ fixation techniques (screw head resting lateral to the intertrochanteric line on the anteroposterior radiograph) may decrease the rate of screw head impingement in moderate and severe SCFEs... - Biomechanical analysis of anterior scoliosis instrumentation: differences between single and dual rod systems with and without interbody structural supportKevin B Fricka
Children's Hospital and Health Center, San Diego, California, USA
Spine 27:702-6. 2002..The use of structural support in dual rod constructs may be helpful in "setting" the desired lordosis, but adds little to construct stiffness... - Displaced pediatric supracondylar humerus fractures: biomechanical analysis of percutaneous pinning techniquesSteven S Lee
Children's Hospital and Health Center, San Diego, California 92123, USA
J Pediatr Orthop 22:440-3. 2002.... - Thoracoscopic multilevel anterior instrumented fusion in a goat modelPeter O Newton
Children s Hospital and Health Center, San Diego, CA, USA
Spine (Phila Pa 1976) 28:1614-9; discussion 1620. 2003..A survival study in a caprine model for evaluation of a thoracoscopic anterior scoliosis instrumentation construct for fusion... - Biomechanical analysis of antegrade and retrograde flexible intramedullary nail fixation of pediatric femoral fractures using a synthetic bone modelKevin B Fricka
Department of Orthopaedic Surgery, Children's Hospital, San Diego, California, USA
J Pediatr Orthop 24:167-71. 2004..However, there appeared to be a biomechanical trend of greater resistance to shortening for antegrade nails... - Strut allograft union and remodeling using rhBMP-2 in a spinal corpectomy modelKlane K White
Department of Orthopaedic Surgery, University of California San Diego, San Diego, CA, USA
Spine 30:1386-95. 2005..CONCLUSIONS: Large cortical strut allografts (after lumbar corpectomy) supplemented with rhBMP-2 had incorporation and fusion strength comparable to allografts enhanced with cancellous autograft... - Thoracic vertebral screw impingement on the aorta in an in vivo bovine modelFran D Faro
University of California, San Diego, CA, USA
Spine 30:2406-13. 2005..This model represents a severe form of vessel penetration by a screw that confirms such a "worst case" scenario results in marked compromise of the vessel wall integrity. The sequelae of less severe impingement are unknown... - Pullout strength of thoracic pedicle screw instrumentation: comparison of the transpedicular and extrapedicular techniquesKlane K White
Department of Orthopaedic Surgery, University of California, San Diego, CA, USA
Spine 31:E355-8. 2006..This difference is small, however, and we think that extrapedicular screws offer an excellent alternative when anatomy dictates their use with other screws in segmental spinal constructs... - Effects of a novel sterilization process on soft tissue mechanical properties for anterior cruciate ligament allograftsAimee Schimizzi
Department of Orthopaedic Surgery, University of California at San Diego, San Diego, California, USA
Am J Sports Med 35:612-6. 2007..Allograft anterior cruciate ligament reconstruction provides benefits such as earlier return to activities and less pain, but concerns remain regarding potential infection and biomechanical stability... - Biomechanical stability of bioabsorbable screws for fixation of acetabular osteotomiesMark J Adamczyk
Akron Children s Hospital, Akron, OH, USA
J Pediatr Orthop 27:314-8. 2007..Confirmation of biocompatibility should be completed before widespread clinical application... - Asymmetrical flexible tethering of spine growth in an immature bovine modelPeter O Newton
Children s Hospital San Diego, USA
Spine (Phila Pa 1976) 27:689-93. 2002..A 12-week bovine survival study of tethering anterior spine growth that included untethered control subjects...