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Biomedical subjects

Michael J Voor

Publications and source records attributed to Michael J Voor.

18 recordsLinked to original sources
PubMed2006

Scapular thickness--implications for fracture fixation.

The purpose of this study was to measure and map scapula osseous thickness to identify the optimal areas for internal fixation. Eighteen (9 pairs) scapulae from 2 female and 7 male cadavers were used. After harvest and removal of all soft tissues, standardized measurement lines were made based on anatomic landmarks. For consistency among scapulae, measurements were taken at standard percentage intervals along each line approximating the distance between two consecutive reconstruction plate screw holes. Two-mm-diameter drill holes were made at each point, and a standard depth gauge was used to measure thickness. The glenoid fossa (25 mm) displayed the greatest mean osseous thickness, followed by the lateral scapular border (9.7 mm), the scapula spine (8.3 mm), and the central portion of the body of the scapula (3.0 mm). To optimize screw purchase and internal fixation strength, the lateral border, the lateral aspect of the base of the scapula spine, and the scapula spine itself should be used for anatomic sites of internal fixation of scapula fractures.

Aged↗
PubMed2005

A biomechanical comparison of Bosworth and poly-L lactic acid bioabsorbable screws for treatment of acromioclavicular separations.

PURPOSE: The purpose of this study was to determine the failure load of intact coracoclavicular ligaments and the pullout strength of a poly-L lactic acid screw (PLLA, Linvatec, Largo, FL) compared with a titanium screw (Bosworth, Stryker Howmedica Osteonics, Allendale, NJ) in the repair of fifth-degree acromioclavicular separations. TYPE OF STUDY: Biomechanical cadaveric study. METHODS: The ultimate tensile strength of coracoclavicular ligaments was determined using a servohydraulic testing machine (MTS, Eden Prairie, MN) by creating grade V acromioclavicular separations. Titanium Bosworth screws and Linvatec PLLA screws were placed across the reduced coracoclavicular joint and through the base of the coracoid process of right and left matched cadaveric shoulder specimens, respectively. The axial pullout strength was determined by MTS uniaxial tensile testing along the screw axis to determine the ultimate fixation failure load at a rate of 1 mm/second. RESULTS: Intact coracoclavicular ligaments required an axial load of 340.15 +/- 100.77 N to fail. The bioabsorbable PLLA screw provided fixation strength that was significantly less than the Bosworth screw fixation strength: 272.01 +/- 63.26 and 367.01 +/- 111.54 N, respectively (P < .05, paired t test). CONCLUSIONS: The titanium Bosworth screw restored strength to the acromioclavicular joint equivalent to the intact coracoclavicular ligament; however, the bioabsorbable PLLA screw fixation was significantly weaker than the intact ligaments and the Bosworth repair. CLINICAL RELEVANCE: Titanium Bosworth screws supply more strength of fixation in grade V acromioclavicular separations than the PLLA screw tested in this study.

Absorbable Implants↗
PubMed2005

The effect of transfixion wire crossing angle on the stiffness of fine wire external fixation: a biomechanical study.

To analyse the effect of transfixion wire-crossing angle on the stiffness of fine wire external fixation, a laboratory investigation using a fibreglass tibia fixed into an idealised fixator was performed with a servohydraulic test frame. Load-deformation behaviour was compared at the different wire-crossing angles (30 degrees -90 degrees ) under identical conditions of central axial compression, medial compression-bending, posterior compression-bending, posteromedial compression-bending, and torsion. Stiffness values were calculated from the load-deformation and torque-angle curves. The increase in wire-crossing angle led to an overall increase in the stiffness, except medial bending stiffness. The wire-crossing angle of 90 degrees provided significantly greater stiffness than all other angles in all load configurations (p<0.05) except medial bending. In medial bending, the wire-crossing angle of 30 degrees provided significantly greater stiffness than all the other angles (p<0.05). Increasing wire-crossing angle from 30 degrees to 90 degrees contributed to an overall increase of 75% in external fixation stiffness, which included axial, torsional, and bending stiffness, but bending stiffness was a function of the wire positioning with respect to the loading axis. Therefore, using the widest possible wire-crossing angle and placing wires as close to the loading plane as possible can increase the stiffness of external fixation.

Biomechanical Phenomena↗
PubMed2005

The effect of wire plane tilt and olive wires on proximal tibia fracture fragment stability and fracture site motion.

To analyze the effect of the tilt angle relationship between the crossed wire plane and the bone axis on the stiffness of fine wire external fixation, load-deformation behavior was compared across different tilt angles (0 degree, 10 degrees, and 20 degrees) of the plane containing crossed smooth or olive wires under identical conditions of central axial compression, medial compression-bending, posterior compression-bending, posteromedial compression-bending, and torsion. Stiffness values were calculated from the load-deformation and torque-angle curves. A tilt angle of 20 degrees with olive wires provided significantly greater stiffness compared to smooth wires at any angle in any loading condition (p < 0.05). A tilt angle of 20 degrees with olive wires was also significantly more stiff than a tilt angle of 0 degree with olive wires in any loading condition. In torsion, olive wires with 10 degrees and 20 degrees tilt were not significantly different, while in posterior bending olive wires with 10 degrees tilt were significantly stiffer than olive wires with 0 degree or 20 degrees tilt. With smooth wires, tilting the wire plane caused a decrease in stiffness in posterior bending, posteromedial bending, and torsion. Overall, the use of olive wires in conjunction with tilting the wire plane enhances the fixation stiffness for proximal tibia fractures while allowing more options for wire configurations that avoid neurovascular and musculotendinous structures, and wounds.

External Fixators↗
PubMed2005

The effect of transfixion wire number and spacing between two levels of fixation on the stiffness of proximal tibial external fixation.

OBJECTIVES: Anatomic constraints about the proximal tibia limit the ability to insert wires at the biomechanically optimum angle of 90 degrees, thus diminishing the potential stability of external fixators used for proximal tibial fractures. To overcome this problem, surgeons use more than 2 wires at a single level of fixation or a second level of fixation. This study evaluated the effect of transfixion wire number and placement of a second level of fixation on the stiffness of proximal tibial external fixation. METHODS: A fiberglass tibia fixed into an idealized ring external frame was tested. Load-deformation behavior was compared among the different wire numbers (1 level with 2, 3, 4, and 5 wires) and placement of a second level of fixation (2 wires first level and 1 wire second level, and 2 wires first level and 2 wires second level) at 2, 3, 4, 5, 6, 7, 8, 9, and 10 cm distance from the first level of fixation. Identical loading conditions of central axial compression, medial compression-bending, posterior compression-bending, posteromedial compression-bending, and torsion were used. Stiffness values were calculated from the load-displacement and the torque-angle curves. RESULTS: An increase in wire number at 1 level led to an overall increase in stiffness, whereas the addition of a second level of fixation and increased spread between these 2 levels increased bending stiffness. CONCLUSIONS: The addition of a second level of external fixation of the proximal tibia fragment with maximum possible distance between the 2 levels increases bending stiffness, whereas increasing the number of transfixion wires increases overall stiffness. Axial and torsional stiffness is proportional to the total number of wires regardless of the number of levels of fixation.

Biomechanical Phenomena↗
PubMed2005

Bone quality and healing in a swine vascularized bone allotransplantation model using cyclosporine-based immunosuppression therapy.

Although vascularized bone and joint allotransplantation is a promising new treatment option for reconstructing large bone defects, the need for immunosuppressive agents to prevent rejection in these procedures poses a major problem. This problem stems from the fact that several of these agents can cause harmful side effects, such as alterations in bone quality and healing. Therefore, the purpose of this study was to determine what effect the commonly used immunosuppressant regimen cyclosporine A-based combination therapy has on bone quality and healing. In 10 pigs, vascularized bone allografts with skin and muscle components (osteomyocutaneous free flaps) were transplanted from size-matched donor animals. Recipient animals received oral cyclosporine A/mycophenolate mofetil/prednisone therapy for 90 days. Bone quality was studied before and after transplantation by measuring the bone's acoustic velocity and density and calculating the bone's elastic coefficient. Bone healing was assessed using radiographic analysis. Four animals were lost as a result of graft rejection or immunosuppression-related complications before the 90-day endpoint of the study. Although bone specimens taken from the six animals that completed the 90-day protocol had histological signs of rejection, they all seemed to have normal bone healing. Posttransplant bone density values were significantly decreased (p < 0.05) (1544.7 +/- 47.5 kg/m3) as compared with pretransplant values (1722.7 +/- 44.1 kg/m3). Results of the acoustic velocity and elastic coefficients measurements showed a significant decrease (p < 0.05) in posttransplant values (from 3503.0 +/- 165.1 meters/sec to 2963.0 +/- 54.6 meters/sec and from 21.6 +/- 2.2 GPa to 13.6 +/- 0.5 GPa, respectively), indicating diminished bone quality. The findings indicate that cyclosporine A/mycophenolate mofetil/prednisone combination therapy is ineffective in preventing bone rejection, that it decreases bone quality, and that it is associated with systemic toxicity, suggesting that this immunosuppressive regimen at the doses used in this study is not ideal for vascularized bone allotransplantation procedures.

Animals↗
PubMed2005

A biomechanical comparison of four extensor tendon repair techniques in zone IV.

BACKGROUND: This study was designed to evaluate the biomechanical parameters of four different suture techniques specifically designed for zone IV extensor tendon injuries: the double figure of eight, the double modified Kessler, the six-strand double-loop, and the modified Becker suturing techniques. Ease of repair, tendon shortening, strength to 1-mm gap, strength to 2-mm gap, ultimate strength, and mode of repair failure were evaluated. METHODS: Twelve fresh-frozen cadaver hand-forearm units (48 fingers) were randomly assigned to the four suture repair treatments. The speed of tendon repair as performed by two matched-hand surgeons was recorded. Prerepair and postrepair tendon lengths were measured to document tendon shortening. The repair was stressed by linear distraction at 2.0 mm/minute using a servohydraulic frame. Video recordings of each distraction were independently reviewed for biomechanical parameters by three physician-observers in a double-blind setup. A one-way analysis of variance and t test analysis was performed. RESULTS: Results show that the double figure-of-eight technique and the double modified Kessler were significantly (p < 0.05) easier to perform at 7 minutes 31 seconds and 7 minutes 58 seconds, respectively, than the other two techniques. Tendon shortening ranged from 1.9 to 2.4 mm. There was no statistically significant difference in tendon shortening among the four techniques. Strength to 1-mm gap was significantly higher with the modified Becker technique, with a mean 28.8 +/- 8.0 N. This was followed by the six-strand double-loop technique, with 21.0 +/- 6.6 N, the double modified Kessler at 17.7 +/- 4.5 N, and the figure-of-eight technique at 17.5 +/- 2.4 N. Strength to 2-mm gap was significantly (p < 0.05) greater for the modified Becker technique and the modified Kessler technique at 56.0 +/- 9.2 N and 48.6 +/- 12.6 N, respectively, as compared with the other two suture methods. The modified Becker technique showed the highest ultimate strength at maximal loading at 63.3 +/- 7.8 N, followed by the double modified Kessler technique with strength of 56.8 +/- 14.8 N. Both were significantly stronger than the other two techniques. CONCLUSIONS: This study shows that the modified Becker suture technique, although not easily performed, proved to be the strongest repair, with a significantly greater resistance to 1-mm and 2-mm gap and the greatest ultimate strength on maximal loading.

Biomechanical Phenomena↗
PubMed2005

Histologic and mechanical evaluation of impaction grafting for femoral component revision in a goat model.

A goat model of revision hip arthroplasty was used to examine the histology and mechanical performance of impaction grafting using two femoral stems varying in stem surface finish. There were no significant mechanical or qualitative histologic differences between smooth, tapered, polished stems and step-cut, grit-blasted stems. Allograft distribution, bone incorporation, and cement mantle thickness were not uniform within the femoral canal. Efforts to improve the impaction grafting technique may be more important than stem design.

Animals↗
PubMed2004

The accuracy of fine wire tensioners: a comparison of five tensioners used in hybrid and ring external fixation.

OBJECTIVES: To compare the accuracy of 5 commonly available fine wire tensioners used in hybrid and ring external fixation. DESIGN: A laboratory investigation. SETTING: The testing of 5 commonly available tensioners was performed with a servohydraulic test frame (MTS Bionix 858, Minneapolis, MN). MAIN OUTCOME MEASUREMENT: The real wire tension data of each tensioner provided by the MTS were compared with corresponding nominal values. The percent error for each tensioner was calculated. Clinical ease of usage of the wire tensioners was also evaluated. RESULTS: The EBI tensioner was the most accurate (-0.17% to 0.09% error). The Smith and Nephew tensioner had a -13.97% to -8.61% error, the How medica tensioner a -12.48% to -10.86% error, and the Synthes tensioner a -0.2% to 24.28% error. The DePuyACE tensioner was the least accurate, with errors ranging from -36.76% to -30.92%. The Howmedica tensioner was the easiest to use, followed by the Smith and Nephew tensioner, the DePuyACE tensioner, the Synthes tensioner, and the EBI tensioner. CONCLUSIONS: Most commonly available tensioners tend to undertension. Future efforts should focus on the development of wire tensioners that combine accuracy and ease of usage.

Bone Wires↗
PubMed2003

Optimal entry point for retrograde femoral nailing.

OBJECTIVE: The purpose of this study is to identify the optimum entry point for retrograde femoral nailing, defined as that point which will provide adequate fracture alignment while minimizing soft-tissue and articular cartilage injury. DESIGN: Cadaveric study. SETTING: Biomechanics laboratory. MAIN OUTCOME MEASURE: Anatomic relationships and fracture reduction. METHODS Eleven cadaveric femori with attached knee joints underwent retrograde femoral nailing with a Synthes femoral nail (Synthes, Paoli, PA, U.S.A.). After placement of the nail, the specimens underwent an osteotomy 3 inches proximal to the articular surface. Multiple entry points were tested to determine fracture alignment and extent of articular cartilage injury. Medial-lateral and anterior-posterior displacements, in addition to any soft-tissue or articular surface trauma, were recorded for these various points of entry. RESULTS: An entry point of 1.2 cm anterior to the femoral origin of the posterior cruciate ligament resulted in the least anterior-posterior displacement of the femoral shaft following fracture. In the coronal plane, an entry point at the midpoint of the intercondylar sulcus was identified as minimizing the displacement following fracture. This ideal position allows for proper seating of the nail within the intercondylar sulcus, resulting in minimal damage to the articular cartilage and posterior cruciate ligament and minimal disruption of the patella femoral joint. CONCLUSION: Retrograde femoral nailing should be used cautiously in select patients, when conventional antegrade nailing cannot be used, due to the unavoidable injury to the knee articular surface associated with this technique. The optimum entry point of 1.2 cm anterior to the femoral posterior cruciate ligament origin and centered in the intercondylar sulcus provides the optimal balance of fracture reduction and knee joint sparing. It may be difficult to target this site with a percutaneous technique and may require direct visualization of the intercondylar sulcus for ideal nail placement.

Anterior Cruciate Ligament↗
PubMed2003

Hybrid external fixation of the proximal tibia: strategies to improve frame stability.

OBJECTIVE: To determine the specific frame construction strategies that can increase the stability of hybrid (ring with tensioned wires proximally connected by bars to half-pins distally) external fixation of proximal tibia fractures. DESIGN Repeated measures biomechanical testing. SETTING: Laboratory. SPECIMENS: Composite fiberglass tibias. METHODS: Using the Heidelberg and Ilizarov systems, external fixators were tested on composite fiberglass tibias with a 1-cm proximal osteotomy (OTA fracture classification 41-A3.3) in seven frame configurations: unilateral frames with 5-mm diameter half-pins and 6-mm diameter half-pins; hybrid (as described above), with and without a 6-mm anterior proximal half-pin; a "box" hybrid (additional ring group distal to the fracture connected by symmetrically spaced bars to the proximal rings) with and without an anterior, proximal half-pin; and a full, four-ring configuration. Each configuration was loaded in four positions (central, medial, posterior, and posteromedial). MAIN OUTCOME MEASUREMENTS: Displacement at point of loading of proximal fragment. RESULTS: The "box" hybrid was stiffer than the standard hybrid for all loading positions. The addition of an anterior half-pin stiffened the standard hybrid and the "box" hybrid. CONCLUSIONS: The most dramatic improvements in the stability of hybrid frames used for proximal tibial fractures result from addition of an anterior, proximal half-pin.

Biomechanical Phenomena↗
PubMed2002

Second generation intramedullary nailing of subtrochanteric femur fractures: a biomechanical study of fracture site motion.

OBJECTIVES: To compare fracture site motion between different second-generation intramedullary nails used to fix subtrochanteric fractures of the proximal femur with and without femoral neck fractures. DESIGN: Nondestructive mechanical testing of four types of femoral intramedullary nails was undertaken to evaluate fracture site motion using a model that simulated single-leg and double-leg stance. METHODS: Three types of reconstruction nails (the Russell-Taylor Delta [Smith & Nephew, Memphis, TN], the Uniflex [Biomet, Warsaw, IN], Alta CFX [Howmedica-Osteonics, Rutherford, NJ]) and the Long Gamma nail (Howmedica-Osteonics, Rutherford, NJ), each measuring 11 x 380 mm, were inserted in fiberglass composite femurs. Four fracture patterns were studied (transverse subtrochanteric, subtrochanteric with posteromedial wedge comminution, subtrochanteric with one-centimeter gap, and a one-centimeter gap with a subcapital neck fracture). Single-and double-leg stance loading was simulated using a servohydraulic load frame (MTS, Eden Prairie, MN). Two-way analysis of variance and post hoc t tests were used to determine any statistically significant differences between groups. RESULTS: In single-leg stance there were significant differences in coronal plane rotation, shear, and axial translation across the subtrochanteric fracture site between the different nail types and the different fracture patterns (p < 0.001). In double-leg stance there were significant differences in coronal plane rotation and femoral head vertical motion between the different nail types and the different fracture patterns (p < 0.001), and there were significant differences in shear and axial translation between the different fracture patterns (p < 0.001) but not the different nail types (p > 0.05). CONCLUSIONS: For simple, well-reduced fractures the choice of implant is not critical. As fracture severity increased (comminution, gap, and combined neck fracture), the choice of implant, particularly with reference to proximal nail dimensions and implant materials, was a significant factor in reducing fracture site motion. Therefore, our laboratory data suggest that when subtrochanteric fractures are unstable (e.g., comminution, segmental bone loss) and early weight bearing is desirable, the choice of implant is critical and should be restricted to implants that allow minimal fracture site motion (Long Gamma and Russell-Taylor).

Biomechanical Phenomena↗
PubMed2002

Evaluation of the fixation and strength of a "rescue" revision pedicle screw.

One potential complication of pedicle screw instrumentation is long-term nerve root irritation, most commonly resulting from medial or inferior screw malpositioning. This study evaluated the pullout strength and fatigue strength properties of a novel "rescue" revision screw designed to reduce the sequelae of medial screw malpositioning by eliminating threads along the section of the screw corresponding to the pedicular region. The results of this study revealed that a rescue screw with threads eliminated from one half of its circumference provided comparable pullout strength to fully threaded pedicle screws in cadaveric specimens. In addition, mechanical testing of the rescue screw did not show a decrease in fatigue strength characteristics compared with controls. These results suggest that the rescue screw may offer a way to decrease nerve root irritation caused by canal impingement without jeopardizing the overall strength of the spinal construct.

Aged↗
PubMedDate not supplied

Biomechanics of external fixation of distal tibial extra-articular fractures: is spanning the ankle with a foot plate desirable?

OBJECTIVES: To compare the mechanical stability of external fixation with and without spanning of the ankle joint with a foot plate in an in vitro model of extra-articular distal tibia fractures. DESIGN: A laboratory investigation was performed to evaluate the mechanical behavior of external fixation of extra-articular distal tibia fractures using a fixator with and without a foot plate. Ten fresh-frozen lower extremities (5 pairs) with a simulated OTA 43-A3.3 fracture were stabilized with an Ilizarov hybrid fixator with and without a foot plate. SETTING: All mechanical testing was performed with a servohydraulic test frame (MTS Bionix 858, Minneapolis, MN). MAIN OUTCOME MEASUREMENT: Deformation characteristics as a function of load were compared for an Ilizarov fixator with and without a foot plate under identical conditions of forefoot loading from 0 to 100 N. Relative interfragmentary motions (vertical and horizontal translations and rotation) were measured. RESULTS: There was significantly more vertical translation (2.57 +/- 0.97 mm vs. -0.83 +/- 0.64 mm) and angular displacement (4.49 +/- 0.45 degrees vs. -1.15 +/- 0.61 degrees ) of the distal fragment in the arrangement without a foot plate compared with the construct with a foot plate. The anterior translation of the distal fragment was similar with (1.12 +/- 0.98 mm) and without a foot plate (1.19 +/- 1.23 mm). CONCLUSIONS: This study supports the mechanical importance of spanning of the ankle with a foot plate in most cases of external fixation for unstable extra-articular and periarticular distal tibia fractures. Further studies are needed to validate these results before widespread changes in clinical treatment can be recommended.

Aged↗
PubMedDate not supplied

Mechanical study of the safe distance between distal femoral fracture site and distal locking screws in antegrade intramedullary nailing.

OBJECTIVE: To determine the safe distance for distal femoral fractures relative to the distal locking screws in antegrade intramedullary femoral nailing using a currently available titanium alloy nail design. DESIGN: Cyclic (fatigue) mechanical testing study. SETTING: Biomechanics laboratory. INTERVENTION: Intramedullary nailing of left synthetic fiberglass composite femora with type 32/33-C fractures at 1, 2, 3, and 4 cm from the more proximal of the distal locking screws. MAIN OUTCOME MEASUREMENT: The number of loading cycles to failure of the nail. RESULTS: A load level of 700 N through the femoral mechanical axis was validated as adequate to cause fatigue failure within 200,000 cycles in slotted stainless- steel nails. In the nonslotted titanium alloy nails, this load level caused failure in only 1 of 3 nails with a fracture at 2 cm from the more proximal of the 2 distal locking screws and in 2 of 3 nails with a fracture at 1 cm from the more proximal of the 2 distal locking screws. All of the other nails did not fail >1 million cycles. CONCLUSIONS: Under laboratory conditions, it is safe to assume that an antegrade titanium alloy nail will survive 1 million compression/bending cycles when the fracture is > or = 3 cm from the more proximal of the 2 distal locking screws.

Biomechanical Phenomena↗
PubMedDate not supplied

Biomechanics of olive wire positioning and tensioning characteristics.

The effect of the olive wire on the stiffness of external fixation has been studied previously, but there are limited data on the effect of the olive wire positioning and tensioning characteristics on the stiffness of external fixation. This study evaluated the influence of olive wire positioning (medially, laterally, posteriorly, and anteriorly) and tensioning characteristics (tensioning one end or both ends) on the stiffness of ring external fixation. A fiberglass composite tibia fixed into an idealized ring external frame was tested. All mechanical testing was performed with a servohydraulic test frame (MTS Bionix 858, Minneapolis, MN). Load-deformation behavior was compared among different wire design and olive wire positioning and tensioning characteristics under central axial compression, medial compression-bending, posterior compression-bending, posteromedial compression-bending, and torsion. The differences between tension values on opposite ends of the wire during different modalities of olive wire tensioning were also investigated. Olive wires tensioned on both ends provided significantly greater bending stiffness compared with smooth wires and olive wires tensioned only on the end opposite to the olive (P < 0.05). There was a significant difference between the tension values on opposite ends of the olive wire during tensioning (P < 0.05). Tensioning both ends of the olive wires and positioning the olives on the side of bending significantly increase the bending stiffness of ring external fixation. This work provides a rationale for clinical decision-making about the use of tensioned olive wires opposed to smooth wires in ring external fixation.

Biomechanical Phenomena↗
PubMedDate not supplied

Transfixion wire positioning within the bone: an option to control proximal tibia external fixation stiffness.

PURPOSE: The greatest angle that can be formed by the crossing wires at the proximal tibia level without altering safe corridors approaches only 60 degrees. Consequently, the wires are positioned more in the coronal than the sagittal plane. Looking for an increase in sagittal bending stiffness, we evaluated different wire positioning within the proximal tibia and their effect on the stiffness of external fixation of proximal tibia. STUDY DESIGN: A fiberglass composite tibia fixed into an idealized ring external frame was tested with a servohydraulic test frame. Load-deformation behavior was compared among the different wire positioning within the proximal tibia under identical conditions of central axial compression, medial compression-bending, posterior compression-bending, posteromedial compression-bending, and torsion. Stiffness values were calculated from the load-deformation and the torque-angle curves. RESULTS: The sample with 3 wires positioned within the bone-2 wires crossed 1 cm posteriorly from the center of the tibia and the third wire placed in coronal plane 1 cm anteriorly from the center of the tibia-was significantly (P < 0.05) stiffer in posterior, posteromedial, and torsional loading configurations compared with all other wire positions within the bone. CONCLUSIONS: This new wire positioning within the proximal tibia-2 wires crossed 1 cm posteriorly from the center of the tibia and the third wire placed in coronal plane 1 cm anteriorly from the center of the tibia-increased overall stiffness of external fixation, predominantly in sagittal plane. CLINICAL RELEVANCE: This work provides a rationale to control proximal tibia external fixation stiffness in sagittal plane.

Bone Wires↗