Proportion of Protrusion of Proximal Femoral Nail Antirotation 2 Over the Greater Trochanter in Pertrochanteric Femur Fracture: A Cross-Sectional Study.

Introduction Pertrochanteric femur fractures comprise approximately half of all hip fractures. The proximal femoral nail anti-rotation 2 (PFNA2), designed by Arbeitsgemeinschaft fur Osteosynthesefragen (AO), is an intramedullary device with a helical blade rather than a screw for better purchase in the femoral head. This modification in the proximal femur nail (PFN) was done to adapt to the Asian population and reduce nail-related complications in the Asian population. Materials and methods The study was conducted in a tertiary health center from November 2022 to November 2024 and included 40 subjects with pertrochanteric fractures operated on with PFNA2. Patients were followed up at six weeks and six months. Parker's ratio, nail protrusion height, and Harris Hip Score (HHS) were calculated. Observations and results The majority of the patients in the study belonged to the age group of 60-75 years (37.5%). Nail protrusion height shows wide variability, ranging from 0.00 mm to 29.30 mm, with a mean of 6.01 mm and a considerable standard deviation (SD) of 10.39 mm. Parker's ratio, postoperatively, had a mean of 0.41 with SD of 0.88, ranging from 0.18 to 0.63. HHS was used to perform a clinical evaluation for these patients. The associated p-value for the correlation between Parker's ratio and HHS was 0.002 at six weeks, which is less than the significance level of 0.05, indicating that the correlation is statistically significant. The correlation between nail protrusion height and HHS was calculated by Pearson's correlation coefficient, which at six weeks was 𝑟=-0.210, indicating there was a negative correlation between nail protrusion height and HHS, so as the nail protrusion height increases, the HHS tends to decrease. Conclusion Pertrochanteric femur fracture is common in day-to-day life, with a bimodal age distribution. Our study concludes that PFNA2 is an excellent implant for the treatment of the pertrochanteric femur fracture. All the patients had an excellent follow-up score. A few patients, mainly female patients, had significant nail protrusion over the greater trochanter, with a higher Parker's ratio, and had mild lateral hip pain. The pain was not significant and did not affect the patient's day-to-day activities. This could be improved with the central placement of the helical blade. We do not recommend any changes in nail design; rather, we suggest proper helical blade placement to avoid nail protrusion. These variations due to sex and age should be studied further to establish any changes in implant design. Further studies with a bigger sample size and longer follow-up should be carried out for more definite results.