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Introduction An intertrochanteric (IT) femur fracture is an extra-capsular fracture between greater and lesser trochanters. Unstable IT fractures are those where there is poor contact between fracture fragments (especially medial and posterior cortices), comminution, and fracture pattern, such that the weight-bearing forces tend to displace the fracture further or a reverse oblique type. Proximal femoral nailing (PFN) is one of the modalities for proximal femoral fractures. A newer modality for proximal femoral fracture is PFNA2, i.e., PFN anti-rotation, which makes use of a helical blade for a better compaction of bone. Both nail designs (PFN and PFNA2) are available in short and long sizes (so a total of four variants). Only a few studies have compared the treatment of IT femur fracture concerning fracture geometry, design, and length using either of the two nail types. In our study, we assessed the surgical and functional outcomes of PFN and PFNA2. Materials and methods This prospective observational study was carried out on 30 patients who had sustained IT fractures of the femur. All cases of IT femur fractures more than 18 years of age, closed injuries, and the patients who consented to participate in this program were included in the study. All open injuries, the patients who refused to participate in this program, patients who have associated injuries, patients with a subtrochanteric femur fracture, and patients with less than six months of follow-up were excluded. The patients were randomized into two types of implant groups. All patients were operated with a standard protocol. The study was conducted for 18 months from February 2021 to August 2022. The results were analyzed (of all four variants) by comparing patient demographics, implant size, implant type, locking methods, union time, and other parameters. Results Most of the patients were operated on with a 10 mm nail diameter (17/30 patients), 380 mm length (long-nail group) (five/11 patients), and 250 mm length (short-nail group). With the use of PFNA2, the overall duration of hospital stay was less. The overall operative time (incision to wound closure) with the use of the short PFNA2 was lesser than that with the use of other designs due to the use of the zig for distal screws. The use of a distal dynamic locking screw in a majority of the patients can get better compression at the fracture site once the patient starts weight bearing and decrease the chances of the Z-effect, reverse Z-effect, screw back-out, and screw cut-out. The union time was nearly the same in the majority of the patients, with an early union seen with the use of PFNA2 nails. The overall modified Harris hip score (HHS) at the final follow-up was nearly the same with slightly better results with the use of PFNA2. Conclusions PFNA2 is the implant of choice in elderly patients with osteoporotic bone. It has less operative time, which is required in such patients with medical comorbidities; hence, it has marginal superiority over PFN. Short-nail design results in less operative time and less blood loss.
RESUMO
BACKGROUND: The femoral component is generally aligned perpendicularly to the distal femoral intramedullary axis with conventional instruments. Various aids like computer navigation, patient-specific instrumentation and robotic surgery use the mechanical axis as the reference for the femoral component alignment. We studied the flexion of the distal femoral intramedullary axis compared to the mechanical axis using an interactive 3D tool in 407 Indian osteoarthritic knees undergoing total knee replacement to better understand optimal flexion alignment. MATERIALS AND METHODS: 407 knees (301-Female, 106-Male) in Indian patients undergoing total knee replacement underwent CT scans. A 3D interactive knee system was used for 3D reconstruction and planning. Distal femoral flexion angle (DFFA) was calculated between the anatomic distal femoral (intramedullary) axis and the mechanical axis. Statistical analysis was performed using ANOVA test and Chi-square test using a data analysis tool pack (Analysis ToolPak by Excel Easy) additionally installed in Microsoft Excel 2010. RESULTS: The mean DFFA was found to be 2.54 with a standard deviation of 1.38. The maximum and minimum values noted were 7.5 and 0.5 respectively. There was no correlation found between sex, age, height or weight (p > 0.05). CONCLUSIONS: While taking the distal femur cut with systems other than an intramedullary rod, in Indian osteoarthritic knees, it would be safer to take the distal femoral cut between 2 and 3 degrees of flexion to mechanical axis, as it would ensure that the cut is within 3 degrees from the anatomic axis for 98% patients. Most surgeons routinely using navigation or similar aids take the cut at 0 degrees of flexion to the mechanical axis. This will lead to more than 3 degrees of extension with reference to the intramedullary axis in more than 39% patients. This would result in either an increase in femoral component sizing or an increased risk of notching.