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Transcript of DESIGN RATIONALE RADIUS OF Mobile/Synthes North... DESIGN RATIONALE This optimized fit was...

  • D E S I G N R A T I O N A L E

    RADIUS OF CURVATURE

  • D E S I G N R A T I O N A L E

    This optimized fit was determined by three anatomical studies which: 1. Characterized the native femoral anatomy 2. Validated the resulting fit of the nails in the distal femur

    NAIL FIT VALIDATION: TFNA SYSTEM AND FEMORAL RECON NAIL

    RESULTS

    Less Nail Protrusion Through the Inner Cortex

    The TFNA Nail had a 38% smaller mean total surface area of nail protrusion from the inner cortex surface than Gamma37*

    Improved Distal Fit

    • The distal nail tip was positioned in the far anterior cortex in 59% of Gamma3 samples (vs. 31% TFNA and 21% FRN)

    • The FRN and TFNA nails both had a considerably higher number of center positions than the Gamma3 nail (35% and 25% vs 14%)7,8*

    TFNA Nail and FRN: A Similar Fit in the Distal Femur

    Despite minor differences in proximal nail shape,there was no statistical difference detected in distal nail tip position between the FRN and TFNA Nail group indicating a similar fit and resulting position in the distal femur.8*

    GAMMA3† NAIL (1.5M ROC)

    Distal nail tip positioned in the far anterior cortex 59% of the time8*

    TFN-ADVANCED™ PROXIMAL FEMORAL NAILING SYSTEM (TFNA) & FEMORAL RECON NAIL (FRN)

    Anatomic 1.0m ROC is more centralized in the canal than Gamma3, designed to address complications related to anatomical fit7,8*

    Far Anterior Anterior Center Posterior Far Posterior

    70% 60% 50% 40% 30% 20% 10%

    0

    21%

    31%

    59%

    24%

    38%

    25%

    35%

    25%

    14% 17%

    4% 2% 4% 2% 0%

    A nt

    er io

    r Po

    st er

    io r

    Po si

    tio n

    (% )

    FRN TFN-ADVANCED™ Proximal Femoral Nail System (TFNA) Gamma3

    Despite decreases in nail radius of

    curvature (ROC) over the last decades,

    recent studies still report the existence

    of misfit between the curve of the natural

    femoral anatomy of some patients and

    the curve of the nail.1 This can lead to

    distal cortical impingement, which

    may occur in up to 25% of hip fracture

    repair cases.2-4 This complication may

    lead to a fracture at the distal nail tip,

    called anterior perforation, which

    requires revision surgery. 2,5,6

    COMPLICATIONS FROM NON- ANATOMIC FEMORAL NAIL FIT

    Prior to the development of the TFNA Nail, a comprehensive

    anatomical study of the femur was warranted to properly

    characterize the radius of curvature of the native anatomy

    and serve as the basis for a new nail design.

    Based on the results of the femoral anatomy characterization, both nails were designed with a 1.0m ROC.

    FEMORAL ANATOMY CHARACTERIZATION

    METHODOLOGY

    • 90 3D bone models were constructed from CT Data

    • A computer generated software was used to create the reference geometries for the proximal anatomy and the shaft antecurvature

    ETHNICITY SAMPLE SIZE AGE RANGE

    (YRS) RESULTING MEAN ROC

    Caucasian 47 (37 F, 10 M) 81 +/-9.1 974mm

    Japanese 38 (32 F, 6 M) 71 +/- 4.7 771mm

    Thai 5 (3 F, 2 M) 77 +/- 6.5 906mm

    OVERALL 885mm

    NAIL SYSTEM ROC

    Stryker Gamma 3† & T2

    1.5m, 2.0m

    S&N Trigen† Intertan

    1.5m, 2.0m

    S&N Trigen† TAN FAN

    1.5m-2.5m

    Zimmer† Natural Nail†

    1.27m-1.53m

    STUDY SAMPLE SIZE AGE RANGE (YRS)

    TFNA Nail Fit7* 63 65-103

    FRN Fit8* 82 21-85

    The results of the study indicated an overall ROC of 885mm, suggesting that an ROC of 1m would achieve an improved fit in the investigated population.1

    D E P U Y S Y N T H E S N A I L S A R E D E S I G N E D W I T H A

    1.0M ROC TO BETTER FIT PATIENT ANATOMY

    METHODOLOGY

    Two anatomical studies were conducted utilizing 3D computer modeling to determine fit of the nails in the distal femur.

    • Both studies included samples from Caucasian and Asian decent

    • The results of the FRN Fit Study were compared to the results of the previously completed TFNA Nail Fit Study

    FRN PF

    FRN GT

    TFNA

    Piriformas Fossa (PF) Entry

    Greater Trochanter (GT) Entry

    Gamma3

    RESULTS

    3D Implantation Comparison

    59% of the time, the Gamma3 was FAR ANTERIOR

    IN CENTRAL REGION

    76%

    67% FRN

    TFNA IN CENTRAL REGION 41%GAMMA3

    ROC 2.0m, Straighter Nail

    ROC 1.5m, Bowed Nail

    *Bench test results may not be indicative of clinical performance *Bench test results may not be indicative of clinical performance

  • 1. Schmutz B, Kmiec S Jr, Wullschleger M, Altmann M, Schuetz M. 3D Computer graphical study of the femur: a basis for a new nail design. Archives of Orthopedic Trauma Surgery. 2017 Mar;137(3):321-331.

    2. Roberts JW, Libet A, Wolinsky PR. Who is in danger? Impingement and penetration of the anterior cortex of the distal femur during intramedullary nailing of proximal femur fractures: preoperatively measurable risk factors. J Trauma Acute Care Surg. 2012;73(1):249-254.

    3. Egol KA, Chang EY, Cvitkovic J, Kummer FJ, Koval KJ. Mismatch of current intramedullary nails with the anterior bow of the femur. Journal of Orthopedic Trauma. 2004;18(7):410-415.

    4. Collinge CA, Beltran CP. Does modern nail geometry affect positioning in the distal femur of elderly patients with hip fractures? A comparison of otherwise identical intramedullary nails with a 200 versus 150cm radius of curvature. Journal of Orthopedic Trauma. 2013;27(6):299-302.

    5. Parker MJ, Bowers TR, Pryor GA. Sliding hip screw versus the Targon PF nail in the treatment of trochanteric fractures of the hip: a randomized trial of 600 fractures. The Journal of Bone and Joint Surgery. British volume. 2012;94(3):391-397.

    6. Miedel R, Ponzer S, Tornkvist H, Soderqvist A, Tidermark J. The standard Gamma nail or the Medoff sliding plate for unstable trochanteric and subtrochanteric fractures. A randomized, controlled trial. The Journal of Bone and Joint Surgery. British volume. 2005;87(1):68-75.

    7. Schmutz, B., Amarathunga J, Kmiec S, Jr., Yarlagadda P, Schuetz M. Quantification of cephalomedullary nail fit in the femur using 3D computer modelling: a comparison between 1.0 and 1.5m bow designs. Journal of orthopedic surery and research. 2016; 11(1):53.

    8. DePuy Synthes Trauma. Analysis – FRN Anatomical Study. #0000271671, 2017.

    † Third party trademarks used herein are trademarks of their respective owners.

    Please also refer to the package insert(s) or other labeling associated with the devices identified in this brochure for additional safety information.

    Not all products are currently available in all markets.

    Limited Warranty and Disclaimer: DePuy Synthes products are sold with a limited warranty to the original purchaser against defects in workmanship and materials. Any other express or implied warranties, including warranties of merchantability or fitness, are hereby disclaimed.

    © DePuy Synthes 2019. All rights reserved. 108612-190301 DSUS/EM 05/19

    Manufactured by:

    Synthes GmbH Eimattstrasse 3 4436 Oberdorf Switzerland Tel: +41 32 720 40 60 Fax: +41 32 720 66 00

    Synthes USA Products, LLC 1101 Synthes Avenue Monument, CO 80132

    To order (USA): 800-523-0322 To order (Canada): 844-243-4321

    www.depuysynthes.com