Rewriting the tip apex distance for the proximal femoral nail anti-rotation

Yam, Michael; Chawla, Anuj; Kwek, Ernest Beng Kee

doi:10.1016/j.injury.2017.06.020

Cited by 29 publications

(16 citation statements)

References 22 publications

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“…The length of the main intramedullary nail and mode of distal locking were determined according to the patients’ condition. The location of the femoral neck guide pin was adjusted by axially rotating the main femoral intramedullary nail to alter the entry point and ensure the TAD not exceeding 25 mm [ 9 – 13 ]. The TAD was measured by three individual observers through C-arm x-ray intra-operatively.…”

Section: Methodsmentioning

confidence: 99%

“…It has been a consensus that measuring the tip–apex distance (TAD) on anteroposterior and lateral radiographs is a valuable tool to assist accurate placement of screws or nails for fixation of IFFs. The TAD should be less than 25 or 27 mm in order to reduce the complications of the cut-out and nail breakage, fracture non-union and poor functional outcomes [ 9 – 13 ]. However, intraoperative determination of TAD is difficult and can be hampered by the image quality, body habitus and image projection [ 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

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How to get better TAD? Relationship between anteversion angle of nail and position of femoral neck guide pin during nailing of intertrochanteric fractures

Wang

Liu

et al. 2020

BMC Musculoskelet Disord

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Background: To demonstrate the correlation between guide pin-shaft angle (PSA) at the anteroposterior film and anteversion angle of guide pin at the lateral film and investigate whether excellent tip-apex distance (TAD) can be obtained by changing the entry point via axial rotation of the main intramedullary nail. Methods: Fifty patients with intertrochanteric femoral fractures (IFFs) undergoing internal fixation with intramedullary nails under 2D fluoroscopy were retrospectively enrolled. Both of the PSA at the anteroposterior film and anteversion angle at the lateral film before and after adjustment of the guide pin were collected. Pearson correlation analysis was performed to investigate their correlation. Intraoperative and postoperative outcomes were recorded. Furthermore, the software of Mimics 10.0 and Pro/E were used to establish the 3D models of the proximal femur and main intramedullary nail/guide pin, respectively. Surgery was simulated on the Pro/E software platform and solid geometry analysis was conducted to calculate the correlation between the PSA and the anteversion angle. Results: Pearson correlation analysis indicated there was a positive correlation between PSA and anteversion angle, with the correlation coefficient of 0.902 (p < 0.01). By altering the PSA and anteversion angle, TAD was adjusted to be less than 25 mm in all patients. The mean operative time, fluoroscopy time and length of hospital stay were 65.82 ± 11.16 min, 2.03 ± 0.79 min and 6.66 ± 2.49 d. Thirty-one patients received blood transfusions (3.55 ± 1.95 U). Fracture reduction was considered to be good or acceptable in all patients. Complications occurred only in 6 patients (12.00%). At a 3-month follow-up, the mean Timed Up and Go was 31.54 ± 20.95 s and Harris Hip Score was 72.88 ± 8.79. The 3D surgery model also showed when the main intramedullary nail was externally rotated or internally rotated of 20°at the standard location, the PSA of guide pin at the anteroposterior position and anteversion angle of the guide pin at the lateral position were simultaneously increased or decreased. Conclusion: Our findings suggest altering the PSA and anteversion angle may be beneficial for obtaining excellent TAD and achieving superior outcomes.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

How to get better TAD? Relationship between anteversion angle of nail and position of femoral neck guide pin during nailing of intertrochanteric fractures

Wang

Liu

et al. 2020

BMC Musculoskelet Disord

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“…The PNFA implant model was assembled with the intertrochanteric fracture models according to the PNFA surgical guidelines. In brief, the Tip Apex Distance (TAD) on both the anteroposterior and lateral views, shall be not more than 27mm [7].…”

Section: Model Reconstruction and Mesh Creationmentioning

confidence: 99%

Risk of Proximal Femoral Nail Antirotation Implant Failure Upon Different Lateral Femoral Wall Thickness in Intertrochanteric Fracture :A Finite Element Analysis.

Zheng

Wong

Chen

et al. 2020

Preprint

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PurposePFNA has been commonly used to treat intertrochanteric fractures, despite the risk of implant failure. The integrity of the femur could influence the risk of implant failure. This study aims to evaluate the influence of lateral femoral wall thickness on potential implant failure using a computational modeling approach. MethodsFinite element model of the hip was reconstructed from the Computed Tomography of a female patient. Five intertrochanteric fracture models at different lateral femoral wall thickness (T1 = 27.6 mm, T2 = 25.4 mm, T3 = 23.4 mm, T4 = 21.4 mm, and T5 = 19.3 mm) were created and fixed with PFNA. A critical loading condition was simulated that mimicked a high loading scenario during walking. The implant failure condition, stress and displacement of the PFNA implant and fracture femur were predicted for analysis. ResultsImplant failure of PNFA occurred at the sides of the proximal nail canal especially for the thinner wall models (T4 and T5).The maximum von Mises stress of the nail for T4 changed abruptly to 298.1 MPa. However, thinner wall decreased the displacement of the PFNA implant. There was approximately opponent trend of stress and displacement on proximal and distal fragments with decreasing thickness possibly due to the adaptation after failure.ConclusionA thinner wall increased the risk of PFNA implant failure. Our prediction showed that complete failure occurred when the thickness was 21.4 mm which was close to the value suggested to determine the stability type.

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“…(12,13) It is also reported that these suggestions could not be valid to the fixation of intertrochanteric fractures with intramedullary systems due to the improvements in implant design and biomechanical differences. (14) Although the use of proximal femur nails (PFN) is increasing especially in unstable fractures (15), there is relative information's about predictors of PFN cut-outs. The most important predictors emphasized in the literature are fracture type, implant position, and success in surgical technique.…”

Section: Introductionmentioning

confidence: 99%

Predictors of Cut-Out after Fixation of Intertrochanteric Fractures with Two Cephalocervical Screwed Proximal Femur Nails

2021

GMJ

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Objective: To identify the factors of predicting cut-out development about implant position after fixation of proximal femoral fractures with two cephalocervical screwed femoral nails and to calculate the position-related failure risk. Methods: Retrospective analysis of clinical and radiographic data were performed on hospital records and 20 cases with implant cut-out were included in the study group. 31 cases from a similar epidemiological group who completed the second year without failure were included as a control group. Tip-apex distance (TADAP-TADL), calcar tip apex distance (CalTAD) were measured using radiographs, and Parker ratio was calculated for anteroposterior (ParkerAP) and lateral (ParkerLat) views. Advanced analysis was performed for each statistically significant variable to determine the cut-off point of the predictors for implant cut-out. Results: TADAP-L (p:<0.001), CalTAD (p:0.001) and ParkerLat ratio (p:0.001) calculated were found to have prognostic significance to estimate implant cutout. ParkerLat was found to be the most significant to estimate implant cut-out (p:0.001). The risk of implant cut-out development increased by 7.3 fold in TADAP, 5.7 in TADLat, and 8.6 in CalTAD, and the greatest risk was calculated in ParkerLat, and this increase was 11.5 fold (Cut-off:≥0.58, p:<0,001) Conclusion: Current study confirmed the significant relationship between implant cut-out and inadequate TAD and ParkerLat. The importance of predictors identified to prevent the development of this phenomenon has been demonstrated in this study for two cephalocervical screwed proximal femur nails. It has been shown that the central positioning of the proximal screw inserted while providing osteosynthesis in both anterior-posterior and lateral views was important in preventing cut-out development.

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Rewriting the tip apex distance for the proximal femoral nail anti-rotation

Cited by 29 publications

References 22 publications

How to get better TAD? Relationship between anteversion angle of nail and position of femoral neck guide pin during nailing of intertrochanteric fractures

How to get better TAD? Relationship between anteversion angle of nail and position of femoral neck guide pin during nailing of intertrochanteric fractures

Risk of Proximal Femoral Nail Antirotation Implant Failure Upon Different Lateral Femoral Wall Thickness in Intertrochanteric Fracture :A Finite Element Analysis.

Predictors of Cut-Out after Fixation of Intertrochanteric Fractures with Two Cephalocervical Screwed Proximal Femur Nails

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