Intertrochanteric fractures are among the most common fractures involving the proximal femur and constitute a major health concern because of their high morbidity, mortality, functional disability, and economic burden. Their incidence continues to increase worldwide owing to population aging and the rising prevalence of osteoporosis. Nearly half of all hip fractures are intertrochanteric fractures, and the annual incidence is projected to increase substantially over the coming decades. While elderly individuals usually sustain these fractures following low-energy falls secondary to osteoporotic bone, younger adults are more commonly affected following high-energy trauma such as road traffic accidents or falls from height.[1,2]

Unstable intertrochanteric fractures, corresponding predominantly to AO/OTA 31-A2 and 31-A3 fracture patterns, are characterized by posteromedial comminution, disruption of the lateral femoral wall, reverse obliquity, or subtrochanteric extension. These features significantly compromise fracture stability and increase the likelihood of varus collapse, excessive shortening, implant failure, delayed rehabilitation, and poor functional outcomes if stable fixation is not achieved. Consequently, early operative intervention has become the standard of care to facilitate anatomical reduction, stable fixation, rapid mobilization, and restoration of pre-injury functional status while minimizing complications associated with prolonged immobilization.[3]

Historically, the Dynamic Hip Screw (DHS) served as the preferred implant for most intertrochanteric fractures. Although DHS provides satisfactory results in stable fracture configurations, its mechanical limitations become evident in unstable fractures where excessive collapse, dependence on lateral wall integrity, increased bending forces, and implant failure are more frequently encountered. These shortcomings encouraged the development and widespread acceptance of intramedullary fixation devices, which provide superior biomechanical advantages by positioning the implant closer to the weight-bearing axis of the femur. This reduces the bending moment across the fracture, improves load sharing, and enhances construct stability in unstable fracture patterns.[4,5]

The Proximal Femoral Nail (PFN), introduced by the AO/ASIF group, has become one of the most commonly used intramedullary devices for unstable intertrochanteric fractures. The implant incorporates a lag screw and an anti-rotation screw to achieve controlled fracture impaction and rotational stability. Numerous clinical studies have demonstrated satisfactory fracture union, reduced operative blood loss, shorter hospitalization, and earlier rehabilitation with PFN fixation. Nevertheless, complications such as screw cut-out, screw back-out, the Z-effect, reverse Z-effect, implant migration, and technical difficulties associated with placement of two proximal screws continue to be reported, particularly in osteoporotic bone.[5,6]

To overcome these limitations, the Proximal Femoral Nail Antirotation-II (PFNA2) was developed. PFNA2 replaces the dual screw configuration with a single helical blade that compacts cancellous bone during insertion rather than removing it. This design improves the bone–implant interface, enhances rotational stability, provides greater resistance to varus collapse, and reduces the risk of implant cut-out, particularly in osteoporotic patients. Furthermore, PFNA2 incorporates anatomical modifications specifically intended for Asian populations, including a reduced mediolateral angle, a smaller proximal diameter, and a flattened lateral surface, thereby improving implant fit while reducing lateral cortex impingement and postoperative trochanteric pain.[7,8]

Several comparative studies have demonstrated favourable operative parameters, satisfactory fracture union, and improved functional outcomes with PFNA2 compared with conventional fixation techniques. However, evidence directly comparing PFN and PFNA2 remains inconsistent because differences in implant design, fixation mechanism, fracture configuration, surgeon experience, and patient characteristics may influence postoperative outcomes. Although both implants are widely accepted for unstable intertrochanteric fractures, there is no universal consensus regarding the superior implant for routine clinical practice.[9]

Considering these uncertainties, the present prospective comparative study was undertaken to evaluate and compare PFN and PFNA2 in adults with unstable intertrochanteric fractures. The study specifically assessed operative duration, intraoperative blood loss, functional recovery, fracture union, and implant-related complications to determine whether one implant offers superior clinical and functional outcomes over the other in the management of unstable intertrochanteric fractures.[10]

Study Design This prospective comparative clinical study was conducted to evaluate and compare the clinical, functional, and radiological outcomes of Proximal Femoral Nail (PFN) and Proximal Femoral Nail Antirotation-II (PFNA2) in the surgical management of unstable intertrochanteric fractures in adults. The study was carried out at the Department of Orthopaedics, King George Hospital, Visakhapatnam, Andhra Pradesh, a tertiary care teaching institution. Study Duration The study was conducted over 24 months, from May 2024 to April 2026. Sample Size The sample size was calculated using the standard formula for estimating proportions at a 95% confidence level, considering an expected prevalence of 12.9% and an absolute precision of 9%. The calculated minimum sample size was 53. After accounting for approximately 5% non-participation, the required sample size became 56, which was rounded to 60 participants for convenience and equal allocation between the two study groups. Study Population Sixty adult patients diagnosed with unstable intertrochanteric fractures of the femur and requiring operative fixation were enrolled. Participants were managed with either PFN (n = 30) or PFNA2 (n = 30) according to the treating surgeon's operative protocol. Inclusion Criteria • Adults aged 18–90 years • Both male and female patients • Patients with traumatic intertrochanteric fractures of the femur • Patients willing to participate and providing written informed consent Exclusion Criteria • Age below 20 years • Compound (open) fractures • Pathological fractures • Pre-existing deformity of the affected femur • Subtrochanteric fractures • Patients medically unfit for surgery • Patients unwilling to participate in the study Study Methodology After admission, all eligible patients underwent detailed clinical evaluation, demographic assessment, routine laboratory investigations, and radiographic examination. Fractures were classified using standard radiological classification systems before surgery. Following pre-anaesthetic assessment, patients underwent fixation using either PFN or PFNA2 under appropriate anaesthesia according to standard operative techniques. Operative parameters including duration of surgery and estimated intraoperative blood loss were documented intraoperatively. Standard postoperative management consisting of antibiotics, analgesics, thromboprophylaxis, physiotherapy, and early mobilisation was instituted for all patients. Outcome Measures Patients were followed clinically and radiologically on postoperative day 2, at 6 weeks, 3 months, and between 6 and 12 months. The primary outcome measures included: • Functional outcome using the Modified Harris Hip Score (MHHS) • Radiological union using the Modified Radiographic Union Score for Hip (Modified RUSH Score) • Duration of surgery • Intraoperative blood loss • Implant-related and postoperative complications Ethical Considerations The study protocol received prior approval from the Institutional Human Ethics Committee before commencement. Written informed consent was obtained from every participant. Patient confidentiality was maintained throughout the study, and all collected data were used exclusively for research purposes.

A total of 60 adult patients with unstable intertrochanteric fractures were included in the study, with 30 patients managed using Proximal Femoral Nail (PFN) and 30 patients managed using Proximal Femoral Nail Antirotation-II (PFNA2). Baseline demographic characteristics, fracture patterns, operative parameters, functional recovery, radiological union, and postoperative complications were analysed and compared between the two groups.

Table 1. Baseline Characteristics of the Study Population

Narrative

The demographic characteristics were well balanced between the two treatment groups. Most patients were older than 60 years, with the highest frequency occurring in the 60–69-year age group. Male patients predominated in both groups. Trivial fall was the commonest mechanism of injury, reflecting the predominance of osteoporotic fractures. AO type A2 represented the most frequent fracture configuration, while right-sided fractures were marginally more common than left-sided fractures.

Figure 1: Age Distribution

Table 2. Comparison of Operative Parameters

Narrative

PFNA2 demonstrated consistently favourable intraoperative and early postoperative parameters. A larger proportion of PFNA2 procedures were completed within 55 minutes, were associated with lower intraoperative blood loss, and required fewer fluoroscopic exposures. Patients treated with PFNA2 also achieved earlier postoperative mobilisation and experienced shorter hospital stays than those managed with PFN, suggesting greater operative efficiency and faster postoperative recovery.

Table 3. Functional Outcome According to Modified Harris Hip Score at 12 Months

Narrative

Functional recovery improved progressively throughout follow-up in both treatment groups. At the final 12-month assessment, excellent Modified Harris Hip Scores predominated, particularly among patients treated with PFNA2, where two-thirds achieved excellent outcomes. Poor functional outcomes were uncommon in both groups, although they occurred less frequently following PFNA2 fixation, indicating slightly superior long-term hip function.

Table 4. Radiological Union and Postoperative Complications

Narrative

Radiological union progressed steadily in both treatment groups during follow-up. By 12 months, complete fracture union (Modified RUSH score ≥30) was observed more frequently in the PFNA2 group than in the PFN group. Implant-related complications occurred less frequently following PFNA2 fixation. Notably, Z-effect was observed only among PFN-treated patients, while the overall complication rate remained lower with PFNA2, suggesting improved implant stability.

Figure 2: RUSH score at 12 months

Figure 3. Operative Time Distribution between PFN and PFNA2

The operative duration was generally shorter in the PFNA2 group. Approximately three-quarters of PFNA2 procedures were completed within 55 minutes, whereas PFN procedures more frequently required operative times exceeding 55 minutes. These findings indicate that PFNA2 implantation was technically less time-consuming in the present study.

Post-operative Hospital Stay (Days)

A higher proportion of PFNA2 patients were discharged within 7 days compared to PFN patients. Prolonged hospital stay was more common in the PFN group.

Figure 4: Post-operative Hospital Stay (Days)

FIGURE 5: PRE OPE & POST OPE X RAY

The present prospective comparative study evaluated operative efficiency, postoperative recovery, functional outcome, radiological union, and implant-related complications following PFN and PFNA2 fixation in adults with unstable intertrochanteric fractures. Both implants provided satisfactory fracture stabilization and progressive functional and radiological recovery. However, PFNA2 demonstrated descriptively favourable outcomes in several domains, including operative duration, blood loss, fluoroscopic exposure, early weight bearing, functional recovery, radiological union, and overall complication frequency. Since inferential statistics and corresponding p-values were not reported for these comparisons in the thesis results, the observed differences should be interpreted as descriptive rather than statistically confirmed. Most patients in both groups were in the sixth to eighth decades of life, and trivial falls were the predominant mechanism of injury. This pattern reflects the recognized association between advancing age, osteoporosis, impaired balance, and low-energy hip fractures. Simmermacher et al. similarly reported that unstable proximal femoral fractures predominantly affect older individuals and emphasized that intramedullary fixation provides biomechanical advantages in these patients by reducing the lever arm and improving load transmission.[11] Male predominance was observed in the present study, which may reflect differences in trauma exposure and the hospital population from which the sample was recruited. AO type A2 fractures constituted the largest subgroup in both groups, followed by A3 fractures. The comparable distribution of age, sex, fracture side, mechanism of injury, and AO classification permitted a clinically meaningful comparison between the two implants. Intramedullary devices are particularly suited to unstable configurations because their position close to the mechanical axis decreases bending stress and limits excessive fracture collapse. Gardenbroek et al. reported that cephalomedullary fixation using an antirotation device provided reliable stabilization in unstable pertrochanteric fractures, although outcomes remained dependent on fracture reduction and implant positioning.[12] (FIGURE 5) PFNA2 was associated with a relatively shorter operative duration. Approximately 76.6% of PFNA2 procedures were completed within 55 minutes compared with 66.7% of PFN procedures. This difference may be explained by the single helical blade configuration of PFNA2, which eliminates the need for separate placement of lag and derotation screws. Brunner et al. reported that PFNA fixation allowed efficient stabilization of unstable intertrochanteric fractures, although technical accuracy remained essential to avoid blade-related complications.[13] Similarly, Mereddy et al. described the PFNA design as being adapted to proximal femoral morphology in Asian patients, potentially reducing technical difficulty, lateral cortical impingement, and problems related to implant fit.[14] Intraoperative blood loss also appeared lower with PFNA2. Blood loss of 50–70 mL was recorded in 43.3% of the PFNA2 group compared with 23.3% of the PFN group. Furthermore, 76.7% of PFNA2 procedures required no more than 35 C-arm shots compared with 46.6% of PFN procedures. These findings indicate a potentially simpler insertion technique and reduced need for repeated fluoroscopic confirmation. Liu et al. reported favourable operative and intermediate-term outcomes with anatomically modified PFNA devices in elderly patients, supporting their use where reduced operative trauma and secure fixation are priorities.[15] Takigami et al. also observed acceptable operative parameters and fracture healing with PFNA, while emphasizing the importance of correct entry point, reduction, and blade placement.[16] Postoperative recovery favoured PFNA2, with 46.7% of patients discharged within seven days compared with 30.0% of PFN patients. Early weight bearing within five days was achieved in 40.0% and 20.0% of the PFNA2 and PFN groups, respectively. The helical blade compacts cancellous bone during insertion and provides axial and rotational stability without removing substantial bone. This may improve fixation in osteoporotic femoral heads and increase surgeon confidence when initiating mobilization. Soucanye de Landevoisin et al. reported reliable union after PFNA fixation in elderly patients, although recovery of mobility remained variable because it was also influenced by age, comorbidities, and pre-fracture functional status.[17] Functional outcomes improved progressively in both groups. At six months, excellent Modified Harris Hip Scores were recorded in 40.0% of PFN patients and 53.3% of PFNA2 patients. At 12 months, these proportions increased to 53.3% and 66.7%, respectively. Poor outcomes at final follow-up were uncommon. Singh and Singh highlighted the value of intramedullary fixation in unstable and osteoporotic fracture patterns, where improved mechanical stability may facilitate early rehabilitation.[18] Gupta et al. likewise reported that PFN provides better maintenance of reduction in unstable fractures than extramedullary fixation, confirming the broader advantages of cephalomedullary constructs.[19] The present findings suggest that the design refinements of PFNA2 may provide an additional functional advantage over conventional PFN, although statistical confirmation is required. Radiological healing followed a similar pattern. At 12 months, a Modified RUSH score of ≥30 was observed in 70.0% of PFN patients and 80.0% of PFNA2 patients. These findings indicate satisfactory union with both implants, with somewhat more advanced healing in the PFNA2 group. The improved cancellous bone compaction and rotational control achieved by the helical blade may reduce micromotion and maintain fracture reduction during healing. The overall complication frequency was 33.3% with PFN and 20.0% with PFNA2. Z-effect occurred only in the PFN group, while screw cut-out and residual thigh pain were less frequent with PFNA2. The absence of Z-effect with PFNA2 is consistent with elimination of the dual-screw mechanism responsible for differential screw migration. Nevertheless, malunion and implant breakage occurred in both groups, demonstrating that implant design cannot compensate for inadequate reduction, suboptimal implant placement, poor bone quality, or inappropriate rehabilitation. Comparative work on proximal femoral nails has similarly shown that operative advantages may vary by nail design, whereas final functional outcomes also depend on patient and fracture characteristics.[20] The principal limitations were the single-centre design, modest sample size, absence of reported random allocation, and lack of inferential statistics with confidence intervals. Bone mineral density, reduction quality, tip–apex distance, blade or screw position, comorbidity burden, and time to definite union were not incorporated into the comparative analysis. Despite these limitations, the consistent descriptive trends across operative, functional, radiological, and complication outcomes support PFNA2 as a useful fixation option for unstable intertrochanteric fractures, particularly in elderly patients with potentially osteoporotic bone.

Both Proximal Femoral Nail and Proximal Femoral Nail Antirotation-II provided satisfactory stabilization, progressive fracture union, and functional recovery in adults with unstable intertrochanteric fractures. However, PFNA2 demonstrated more favourable descriptive outcomes across several clinically relevant parameters. Patients treated with PFNA2 had shorter operative durations, lower intraoperative blood loss, fewer fluoroscopic exposures, earlier weight bearing, and shorter postoperative hospital stays. Functional recovery assessed using the Modified Harris Hip Score and radiological healing assessed using the Modified RUSH score were also comparatively better in the PFNA2 group at later follow-up. Implant-related complications, particularly Z-effect and screw cut-out, occurred less frequently with PFNA2. These advantages may be attributed to the single helical blade design, improved rotational control, cancellous bone compaction, and anatomical compatibility with Asian proximal femoral morphology. Nevertheless, because the thesis did not report inferential statistical comparisons, the apparent superiority of PFNA2 should be interpreted cautiously. Larger randomized studies with standardized radiological and functional assessment are required to confirm these findings.

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