New tip-apex distance and calcar-referenced tip-apex distance cut-offs may be the best predictors for cut-out risk after intramedullary fixation of proximal femur fractures

Gaetano Caruso,Chiara Morotti,Nicola Corradi,Daniele Bottin,Vincenzo Lorusso,Giorgia Valpiani,Dario Lo Re,Antonio Caldaria,Leo Massari

doi:10.1038/s41598-021-04252-1

Gaetano Caruso, Chiara Morotti + Show 7 more

Open Access

https://doi.org/10.1038/s41598-021-04252-1

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Journal: Scientific Reports	Publication Date: Jan 10, 2022
Citations: 9	License type: open-access

Affiliation: University of Ferrara

Abstract

Cut-out is one of the most common mechanical failures in the internal fixation of trochanteric hip fractures. The tip-apex distance (TAD), and the calcar-referenced tip apex distance (CalTAD) are the radiographic parameters that most predict the risk of cut-out. The optimal CalTAD value has not yet been defined, but the optimal TAD value is reported as 25 mm or less. However, this cut-off is highly specific but poorly sensitive. The aim of this study was to determine highly specific and sensitive TAD and CalTAD values and shed light on the role of other clinical variables. A total of 604 patients were included in this retrospective cross-sectional study. For each patient the following data were recorded: number of cut-out, AO/OTA classification, quality of the reduction, type of nail, cervicodiaphyseal angle, type of distal locking, post-operative weight-bearing, TAD and CalTAD values, and the position of the screw head in the femoral head according to the Cleveland system. The incidence of cut-out across the sample was 3.1%. The median TAD in the cut-out group was 38.72, while in the no cut-out group it was 22.16. The median CalTAD in the cut-out group was 39.34, while in the no cut-out group it was 22.19. The cut-off values for TAD and CalTAD with highest value of sensitivity and specificity for the risk of cut-out were 34.8 and 35.2, respectively. The incidence of cut-out can be reduced by performing careful minimal reduction and ensuring stable fixation by avoiding TAD > 34.8 mm and CalTAD > 35.2 mm.

Highlights

Cut-out is one of the most common mechanical failures in the internal fixation of trochanteric hip fractures
The exclusion criteria were as follows: proximal femoral fracture involving femur diaphysis or subtrochanteric fractures; pertrochanteric femoral fracture treated with open reduction and internal fixation with long intramedullary nails, extramedullary fixation or other devices; patients without minimum follow-up period of 3 months; pathological fractures induced by tumours or metastatic lesions; and poor-quality x-rays
Limited to the results of our study, in order to reduce the incidence of cut-out, in 31-A2 fractures, it is advisable to perform careful, minimal reduction, and achieve stable synthesis, avoiding tip-apex distance (TAD) > 34.8 mm and calcar-referenced tip apex distance (CalTAD) > 35.2 mm

Summary

Introduction

Cut-out is one of the most common mechanical failures in the internal fixation of trochanteric hip fractures. The optimal CalTAD value has not yet been defined, but the optimal TAD value is reported as 25 mm or less This cut-off is highly specific but poorly sensitive. Several authors have pointed out the benefits of surgery, and early surgical treatment to reduce related mortality is strongly recommended[5,6,7] Nowadays, both extramedullary and intramedullary fixations are viable options[8], but due to its biomechanical and biological advantages, intramedullary nailing has become the most used fixation device in pertrochanteric fractures worldwide, especially in unstable fractures[9,10]. The most common cause of failure for this type of fixation is nail cut-out, which is defined as extrusion of the cephalic screw as a consequence of a varus collapse of the neck–shaft angle[11]. Several authors have reported that longer TADs and CalTADs do not, increase cut-out risk[18,19]

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