Comparison of radiological and functional outcome of unstable intertrochanteric femur fractures treated using PFN and PFNA-2 in patients with osteoporosis

Abstract

Introduction: Presently, unstable intertrochanteric femur fractures are treated commonly with intramedullary nailing devices. Various designs of intramedullary nail are introduced. The conventional Proximal Femoral Nail has given diverse outcome. Complications have also been noted with this implant. Newer designs like Proximal Femoral Nail Antirotation-2 have been introduced for Asian population. The aim of our study was to compare the radiological and functional outcome of unstable intertrochanteric femur fracture treated with conventional Proximal Femoral Nail and Proximal Femoral Nail Antirotation-2 in osteoporotic patients.

Materials and methods: Patients presenting with unstable intertrochanteric femur fracture (AO classification) and Singh's index ≤ 3 were included. Patients were assigned to the groups based on the implant used for treatment (PFN and PFNA2 group). Post-operative radiographs were used to assess the quality of reduction, by calculating neck shaft angle. The quality of fixation was assessed, by calculating tip apex distance and Cleveland index. The duration of surgery, blood loss, number of fluoroscopic images taken and length of hospital stay were noted. Patients were followed up for 6 months, and complications were noted. The functional outcome was compared using modified Harris hip score. The data analysis was done using Student's unpaired t test/Mann-Whitney U test and Chi-square test/Fisher's exact test. A p value less than 0.05 was considered significant.

Results: Seventy-eight patients with unstable intertrochanteric fractures and Singh's index < 3 were included. Thirty-seven were treated with PFNA2 and 41 with PFN. The average age in PFNA2 group was 69.51, and PFN group was 70.804. Nine patients in PFNA2 group and 10 patients in PFN group had tip apex distance more than 25 mm. Twelve patients in PFNA2 group and 14 Patients in PFN group had sub-optimal implant position as per Cleveland index. The difference in neck shaft angle between uninjured and operated side was more than 10° in four patients of PFNA2 group and seven patients of PFN group. The average Harris hip score was 74.55 for PFNA2 group and 69.88 for PFN group. Four complications were seen in PFNA2 group and 5 in PFN group.

Conclusion: The functional outcome (p = 0.102) achieved with both the implants was similar. Good functional outcome can be achieved, when the radiological parameters are restored, i.e. TAD < 25 mm, Cleveland index in centre-centre position and neck shaft angle difference < 5°. The overall complications, in the set-up of osteoporosis, seen with both the implants were similar (p = 0.44). PFNA2 group showed better results in terms of perioperative morbidity.

Keywords: Cleveland index; Intramedullary nailing; Neck shaft angle; Singh’s index; Tip apex distance.