DESIGN RATIONALE RADIUS OF Mobile/Synthes North... DESIGN RATIONALE This optimized fit was...
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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
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%
4% 2% 4% 2% 0%
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
• 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
NAIL SYSTEM ROC
Stryker Gamma 3† & T2
S&N Trigen† Intertan
S&N Trigen† TAN FAN
Zimmer† Natural Nail†
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
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
Piriformas Fossa (PF) Entry
Greater Trochanter (GT) Entry
3D Implantation Comparison
59% of the time, the Gamma3 was FAR ANTERIOR
IN CENTRAL REGION
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.
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© DePuy Synthes 2019. All rights reserved. 108612-190301 DSUS/EM 05/19
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