ระยะ Tip-Apex และปัจจัยทำนายอื่นต่อผลลัพธ์ทางคลินิกของการรักษากระดูกต้นขาหักส่วน Intertrochanteric ด้วยการยึดตรึงแบบ Proximal Femur Nail Antirotation (PFNA)

Phannakij Wanaseangsagul

doi:10.64960/srimedj.v41i5.272197

Authors

Phannakij Wanaseangsagul Department of Orthopaedic Surgery, Surin Hospital, Surin Province, Thailand 32000

DOI:

https://doi.org/10.64960/srimedj.v41i5.272197

Keywords:

intertrochanteric fracture, Proximal Femoral Nail Antirotation (PFNA), screw cutout, Tip-Apex Distance (TAD), bone mineral density, screw-neck ratio

Abstract

Backgroundand objective: Intertrochanteric femoral fractures are a significant public health issue among the elderly. While Proximal Femoral Nail Antirotation (PFNA) is the standard treatment, screw cutout remains a major complication. Traditionally, Tip-Apex Distance (TAD) is used to predict failure, but its predictive value for modern PFNA implants remains controversial. This study aimed to investigate the association between TAD and other clinical and radiological predictors with the incidence of screw cutout in patients treated with PFNA.

Methods: A retrospective cohort study was conducted at Surin Hospital (2019–2023). 163 patients aged ≥ 55 years treated with PFNA were analyzed. Risk factors were identified using univariable and multivariable logistic regression.

Results: Among 163 patients included, screw cutout occurred in 10 cases (6.1%). The mean age was 80.0 years. There was no statistically significant association between TAD and screw cutout (p=0.389). However, univariable analysis indicated that the cutout group had significantly lower hip bone mineral density (BMD) (p=0.005), higher screw-neck ratios (p=0.0006), and a higher prevalence of superior screw positioning (p=0.012) compared to the success group. Penalized Multivariable analysis identified a higher screw-neck ratio as the only independent predictor for screw cutout (p=0.0050).

Conclusion: TAD alone was not a reliable predictor of PFNA failure in this study.Fixation failure appears to be more closely related to poor bone quality and technical factors, specifically superior screw placement and high screw-neck ratios.

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