|Year : 2022 | Volume
| Issue : 1 | Page : 17-23
Proximal femoral nail versus proximal femoral nail Antirotation 2 in the fixation of intertrochanteric fractures: A prospective and comparative study of clinico-radiological outcomes
M Harisankar, Rajanish R Menon, P Gangadharan
Department of Orthopedics, Baby Memorial Hospital, Calicut, Kerala, India
|Date of Submission||23-Dec-2021|
|Date of Acceptance||08-Mar-2022|
|Date of Web Publication||26-Jun-2022|
Department of Orthopaedics, Baby Memorial Hospital, Calicut - 673 004, Kerala
Source of Support: None, Conflict of Interest: None
Intertrochanteric fractures of the femur is one of the most common fractures encountered by an orthopedician during his practice. Hence, it is considered highly relevant to compare the clinico-radiological outcome of intertrochanteric fractures treated with the two different intramedullary implants – proximal femoral nail (PFN) and PFN Antirotation2 (PFNA2) with a critical note on their efficacy. Source of Clinical Data: The clinical material for the present study consists of 78 cases of fresh trochanteric fracture of traumatic etiology meeting the inclusion and exclusion criteria. Study Design: This is a prospective, randomized comparative study. Conclusion: There was no significant difference between the two groups in terms of clinical or functional outcome. However, fluoroscopic exposure and the duration of surgery were significantly lower with PFNA2. Hence, we conclude that PFNA2 is a better option for the treatment of intertrochanteric fractures of hip.
Keywords: Comparison, intertrochanteric fractures, intramedullary implant, outcome, proximal femoral nail antirotation 2, proximal femoral nail
|How to cite this article:|
Harisankar M, Menon RR, Gangadharan P. Proximal femoral nail versus proximal femoral nail Antirotation 2 in the fixation of intertrochanteric fractures: A prospective and comparative study of clinico-radiological outcomes. J Orthop Assoc South Indian States 2022;19:17-23
|How to cite this URL:|
Harisankar M, Menon RR, Gangadharan P. Proximal femoral nail versus proximal femoral nail Antirotation 2 in the fixation of intertrochanteric fractures: A prospective and comparative study of clinico-radiological outcomes. J Orthop Assoc South Indian States [serial online] 2022 [cited 2022 Aug 16];19:17-23. Available from: https://www.joasis.org/text.asp?2022/19/1/17/348317
| Introduction|| |
Trochanteric fractures are common in elderly people. Though people of all age groups are affected, those in the 5th–7th decades of their life have been mostly prone to these fractures. The frequency of these fractures has increased considerably due to the increasing life span and more sedentary lifestyle. Older patients badly withstand their immobilization in bed; they are threatened with hypostatic pneumonia, catheter sepsis, cardiorespiratory failure, and decubitus. Moreover, nursing care is also difficult when the patient is bedridden. All these necessitate urgent surgical solution, because early rehabilitation and mobilization of the patient can only be possible in this way.
The role of the surgeon in operative treatment by internal fixation lies in selecting the appropriate fixation device and its proper application after adequate fracture reduction. There are a large number of devices available for operative treatment for the present-day surgeon. The extramedullary fixation devices for the fixation of intramedullary fractures have been slowly phased out, because biomechanical studies prove beyond any reasonable doubt that intramedullary nail devices are more stable under loading. Among the intramedullary devices, the two most commonly used cephalomedullary implants are the proximal femoral nail (PFN) and the PFN Antirotation 2 (PFNA2). They feature differences in implant design in the form of two head screws for proximal locking in PFN and a single helical blade for the proximal locking in PFNA2.
Hence, it is considered highly relevant to compare the clinico-radiological outcome of intertrochanteric fractures treated with the two different intramedullary implants – PFN and PFNA2 with a critical note on their efficacy.
| Materials and Methods|| |
Source of clinical data
The clinical material for the present study consists of 78 cases of fresh trochanteric fracture of traumatic etiology meeting the inclusion and exclusion criteria, attending outpatient department or Casualty of Baby Memorial Hospital, Calicut, between June 2018 and November 2018.
This is a prospective, randomized comparative study.
- Patients with closed intertrochanteric fractures
- Patients above 20 years and below 100 years of age.
- Pathological fractures
- Patients who present to casualty after 7 days of trauma
- Patients with associated head injury or other system injuries.
Calculation of sample size:
The sample size was calculated based on the study by Kashid et al.
The sample size was determined using the following formula:
where SDp2= (SD12 + SD22)/2
SD1- Standard deviation of mean operative time in PFN taken as 8.20 min
SD2- Standard deviation of mean operative time in PFNA2 taken as 6.03 min
d- Clinically relevant mean difference between operative time in PFN and PFNA2 taken as 5
Based on assumption from the previous studies:
α = Significance level (5%)
1 − β = Power (80%)
n = No. of cases in each group
Minimum sample size needed in each group was taken as 32.
All the patients were evaluated completely, and routine investigation was done. Diagnosis was made based on clinical finding and radiological examination. X-ray pelvis with both hip antero-posterior view and lateral view of the affected hip was sufficient for diagnosis.
Patients with suspected trochanteric fracture satisfying the inclusion and exclusion criteria were included in our study. All the patients were evaluated for associated medical problems and necessary treatment were given. Associated injuries were evaluated and treated simultaneously. Local ethical committee approval was taken and a written informed consent from patients was obtained. All the patients were divided into two groups: Group A for PFN and Group B for PFNA2 by simple randomization. All the patients underwent preanesthetic checkup, and once they are fit, they were operated as early as possible, with either PFN or PFNA2.
Statistical analysis was done using SPSS software (IBM Corp., located in Armonk, N.Y., USA). Statistical difference between continuous variables was assessed using Student's t-test. Categorical variables were compared using Chi-square test. Statistical significance was set at P < 0.05.
| Results|| |
Our study consisted of 81 cases of intertrochanteric fractures of femur treated surgically by PFN in 39 cases and PFN-antirotation in 42 cases, of which 78 patients were available for follow-up. Only those who were available for follow-up were included in the study. All the patients selected in the study walked normally before the injury.
In our study, maximum age was 94 years and minimum was 45 years with a mean age of 73.9 ± 11.7 years. The mean age of the patients in the PFN group was 75.33 years and that in the PFNA2 group was 72.59 years [Table 1].
The difference was found to be not statistically significant (P = 0.182).
In the study, out of the 78 patients, in PFN, 14 (36.8%) were male and 24 (63.2%) were female, and in the case of PFNA2, 21 (52.5%) were male and 19 (47.5%) were female. There was no significant difference in the gender distribution among the two groups (P = 0.165).
In the study, out of 78 cases, 13 (13.7%) cases were due to road traffic accident (RTA) and the rest 65 (83.3%) were due to a trivial trauma [Table 2], thus making trivial trauma the most common cause.
Out of 78 patients, 40 (51.3%) had an injury of the right femur and the rest 38 (48.7%) had an injury to the left femur [Table 3]. There was no statistically significant side predilection for the injury (P = 0.816).
The fractures were classified as per Boyd and Griffin classification system and were grouped accordingly. Type 1 fractures were the most common in both groups, contributing to 50% of the patients in the PFN group and 65% of the patients in the PFNA2 group [Table 4]. The distribution of frequency of incidence of various fracture types among the two groups was found to have a P = 0.576 and was found to be statistically not significant.
The minimum duration of surgery in PFN was 80 min and the maximum duration of surgery was 120 min. The minimum duration of surgery in PFNA2 was 80 min and maximum duration of surgery was 110 min [Table 5]. PFNA2 group had a decreased operative time when compared to the PFN group, and the difference was found to be statistically significant with a P = 0.049.
|Table 5: Comparison between proximal femoral nail and proximal femoral nail antirotation2 with respect to different variables|
Click here to view
The minimum fluoroscopy time in PFN was 42 s and maximum was 62 s. The minimum fluoroscopy time in PFNA2 was 40 s and maximum was 62 s [Table 5]. There was a statistically significant difference in surgical time between the two groups with a P value significant at 1% level.
Majority of the patients (69, 88.5%) resumed full weight bearing mobilization in the 12th postoperative week [Table 6]. The difference between the two groups was statistically not significant with a P = 0.559.
There were no postoperative complications such as infection, screw cut out or cut through, or fracture shaft distal to the implant at the end of 24 weeks follow-up in either PFN or PFNA2 group.
Functional outcome was assessed at the end of 6 months based on Harris Hip Score, and it was classified according to the score attained into 5 groups ranging from excellent to failed. The Harris Hip score among the patients ranged from 30 to 91 with a mean score of 80.9 ± 11.7. The mean Harris hip score in the PFN group was 81.4+/‒10.1, and that among the PFNA2 group was 80.6+/‒13.2. The difference was statistically not significant with a P = 0.767 [Table 5].
The Harris hip score was further graded in to 5 groups [Table 7], with results ranging from excellent to failed. The difference in functional outcome in both the groups was statistically not significant with a P = 0.546.
The RUSH score, was calculated at the end of 6 months and among the patients it ranged from 10 to 30 with a mean score of 27.69 ± 4.2. The mean RUSH score in the PFN group was 27.8+/‒3.9 and that in the PFNA2 group was 27.6+/‒4.6 [Table 5]. The difference between the two groups was found to be statistically not significant with a P = 0.845. The score was comparable among the two groups.
Fracture is said to be in nonunion when the score is <18. The number of patients that had failure of union was 2 each from both groups. The results on statistical analysis gave a P = 1.000, thus making the difference not significant [Table 8]. The rate of nonunion in this study was comparable between the two groups.
Majority of the patients (64, 82.1%) had some comorbidities. The difference in the incidence of comorbidities among both the groups revealed a P = 0.096, thus making it statistically not relevant.
When the type of fracture was plotted against the Harris hip score achieved at the end of 6 months follow-up [Table 9], it gave the following result. Type 1 and 2 fractures on treatment gives good postoperative functional outcomes when compared to more comminuted fracture types (Type 3 and 4), with P = 0.011 making it statistically significant at 1%.
| Discussion|| |
Intertrochanteric fractures of the femur are relatively common injuries among the elderly individuals. Sometimes the associated geriatric problems make it a terminal event in their lives. In order to reduce the morbidity and mortality associated with conservative management of intertrochanteric fractures, surgical management is advocated as the best modality of management of these fractures.
The present study was conducted on 78 adult patients with trochanteric fractures managed surgically using either PFN or PFNA2. The patients' age ranged from 45 years to 94 years with a mean age of 73.9 years. The mean age of the PFN group was 75.33 years and that of the PFNA2 group was 72.59 years. This is in par with the general finding that the intertrochanteric fracture is usually a fracture of the elderly. In a similar study by Kashid et al., the mean age for the PFN group was 64.36, and the mean age of PFNA2 group was 65.36. In a study by Saudan et al., the average age of incidence of peritrochanteric fracture was 83. Nuber et al. in their study had the average age of incidence to be 81.5. Age distribution in some similar studies is tabulated in [Table 10]. This has been generally attributed to the higher incidence of osteoporosis with advancing age that leads to fractures even with trivial falls.
|Table 10: Patient demographics of the present study and the patient demographics of other similar studies reported earlier - A comparison|
Click here to view
Out of the 78 patients in the present study, 35 were male and 43 were female. In a study by Saudan et al., 77.6% of the patients were female and 22.4% were male. In a study by Pajarinen et al., 75.9% of the affected patients were female and 24% were male. These studies showed a clear female predilection for intertrochanteric fractures. Accordingly, in our study, 55% were female and 45% were male.
Most of the cases (65, 83.3%) were due to trivial low energy falls, making it the most common mechanism of injury in the present study. The rest of the cases were due to RTAs. This finding is consistent with the study by Pajarinen et al. which in 2005 reported that 89.8% of the injuries were due to trivial fall. All the fractures that occurred in younger individuals, <55 years of age, were due to high-energy injuries in the form of RTAs. This supports the view that bone stock plays an important role in the causation of fractures in the elderly. No attempt was made to measure the degree of osteoporosis by Singh's index as it involves great interobserver variability.
In the present study, the fractures were classified according to Boyd and Griffin classification. Most of the fractures (45, 57.7%) belonged to Boyd and Griffin Type 1 fracture pattern, followed by Type 2 (20, 25.6%). Type 3 (6, 7.7%), and Type 4 (7, 9%) fractures, and the more comminuted types were lower in incidence. More comminuted fractures occur in high-energy injuries. This might be the reason for simpler fracture types being more common as the most common injury that causes an intertrochanteric fracture is a low-energy injury such as slip and fall at home. This finding is consistent with the study of Kashid et al., where simple fracture types made up 64% of the cases in the first group and 76% of the cases in the second group. Similarly, a study by Schwab et al. showed AO type Group A2 to be the most common type (60.7%) of peritrochanteric fractures. Schipper et al. in 2004 in a study had a similar distribution of fracture types, with Group A2 being the most common fracture type (73.9%) among peritrochanteric fractures.
The mean duration of surgery was significantly lower (P = 0.049*, significant at 5% level) in the PFNA2 group as compared to the PFN group. This was believed to be due to the difference in the implant design. PFNA2 uses a single helical blade for fracture stabilization as compared to two screws in PFN. The PFNA2 involves gentle tapping of the helical blade over a guide pin, thereby avoiding the steps involved in reaming of canals for lag screw and de-rotation screw as required in a PFN. The positioning of the guide wire for insertion of helical blade is also easier as compared to two guide wires for PFN. This finding is in accordance with the findings from other similar studies by Kashid et al., Mallya et al., and Mohan et al., as shown in [Table 11].
|Table 11: Flouroscopic exposure and duration of surgery in the present study and in some studies that were reported earlier – A comparison|
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In our study, exposure to X-rays, as determined by the intraoperative fluoroscopic exposure time, showed significantly lower scores (P < 0.001**, significant at 1% level) for PFNA2 as compared to PFN. According to Zeng et al., PFNA2 use was associated with a significant reduction in the duration of surgery, overall complication rate, postoperative fixation failure rate, and intraoperative blood loss as compared to PFN. Takigami et al. also reported lower surgical time and intraoperative blood loss with the use of PFNA2 as compared to PFN. Kashid et al. reported that fluoroscopy time, duration of surgery, and intraoperative blood loss were less in the PFNA2 group when compared with the PFN group. The lesser fluoroscopy time and hence lower radiation exposure in PFNA2 group has been attributed to the use of a single helical blade in the place of two neck screws as is used in the PFN group. Correct place ment of neck screws/blade demands visualization using C Arm and hence, the more the number of screws/helical blade needed to be placed in the neck, the more will be the radiation exposure.
Postoperative mobilization protocols were the same for both the groups. Mobilization of the hip and knee was started between 2nd and 4th postoperative days for both PFN and PFNA2 groups. Though all patients were encouraged to start the full weight bearing walk in the 12th postoperative week, some patients were unable to do so due to pain. In those patients, weight bearing was delayed by a few weeks. However, the difference in the time to start full weight bearing walk between the two groups was found to be statistically not significant. This is comparable to a study by Mohan and Shivaprakash in which all the patients in both PFN and PFNA2 groups started full weight bearing mobilization by the end of 10th postoperative week.
There were no postoperative complications like infections, or fracture shaft of femur distal to the implant at the end of 24 weeks follow up in 78 cases treated with either PFN or PFNA2. There were no cases of screw cut out or screw cut through in the present study after 24-month follow-up. Nikoloski et al. in their study recommended a (tip apex distance [TAD]) of 20–30 mm in the case of helical blade devices as compared to conventional compression screw devices and observed bimodal incidence of cut out/cut through when the TAD was >30 mm or <20 mm. Mora et al. recommended PFNA for the treatment of trochanteric femoral fractures in the elderly as PFNA's blade demonstrated a lower incidence of cut out in their study. They argued that the blade improved fixation stability, decreased bone loss of the remaining bone stock, increased the contact area between the implant and the femoral head, and compacted the cancellous bone. However, the present study did not show any significant difference in terms of cut out/cut through between the two groups.
The functional outcome was assessed with the help of Harris hip score. The hip score was calculated at the end of 24-week follow-up. The mean Harris hip score in the PFN group was 81.4+/‒10.1 and that in the PFNA2 group was 80.6+/‒13.2. This difference on statistical analysis revealed a P = 0.767, thus rendering the difference statistically not significant. Further, the Harris hip score was graded into 5 groups, with the results graded as excellent (Harris hip score 90–100), good (80–89), fair (70–79), poor (60–69), and failed (<60). There was no statistically significant difference between the two implant groups regarding functional outcome. This is in accordance with the study published by Kashid et al. and by Mallya et al. Both these studies showed no statistically significant difference in functional outcome between the two implants. This has been tabulated in [Table 12].
|Table 12: Radiological and functional outcome of the present study and those that were reported earlier - A comparison|
Click here to view
The functional outcome at the end of 6 months obtained with both PFN and PFNA2 groups in this study was comparable and was in accordance with other previously published articles.
The radiological outcome of the patients in this study was assessed by means of RUSH score., The RUSH score of the 78 patients calculated 6 months after the surgery in this study ranged from 10 to 30 with a mean score of 27.69+/‒4.2. The mean RUSH score of the PFN group was 27.8+/‒3.9 and that for the PFNA2 group was 27.6+/‒4.6. This difference on statistical analysis revealed a P = 0.845, thus rendering this difference statistically not significant. Further, the assessment of nonunion with a reference score of 18, below which it was termed a nonunion was done. However, these data were statistically analyzed and was found to have a P = 1.000, thus rendering the difference in radiological union at the end of 6 months between the two groups statistically not significant. This is in accordance with similar studies published in the literature by Kashid et al., Mohan and Shivaprakash, and Mallya et al., which showed no significant difference in radiological union between the two implants [Table 12].
Analysis of the 6 months' postoperative Harris hip score against the fracture types according to Boyd and Griffin revealed simpler fracture types (Type 1 and 2) to have a better functional outcome than the more complex fracture types (Type 3 and 4). This difference on statistical analysis showed a P value of 0.011, making the observation statistically significant at 1%. This finding can be explained as simpler fracture types are by definition less comminuted fractures when compared to more complex fracture patterns in Type 3 and 4. Not only does this makes the fracture reduction more troublesome in Boyd and Griffin Types 3 and 4, but also the comminution also paves way for an undesirable varus collapse in the postoperative period. This finding is in accordance with similar studies by Kashid et al. and Mallya et al., which also showed better functional and radiological outcomes in patients with simpler fracture patterns. Kashid et al. and Mallya et al. in their studies followed the AO classification system, whereas in this study, we followed the Boyd and Griffin classification system. Regardless, both the reference studies and the present study showed better functional outcome with simpler fracture patterns irrespective of the type of implant used.
Limitations of the study
As the study was time bound, the patients were followed up for a period of 6 months only and the long-term effects of these interventions have to be assessed in future.
In this study, the radiological union of fractures was assessed only at the end of 6 months. Hence, the comparison as to which implant provides earlier fracture union cannot be commented from this study. Also, further follow-up of patients with fractures that remain ununited at the end of 6 months was not possible in this study due to the time constraint. A longer follow-up study would shed light in this matter.
Another handicap relates to the scoring system used for assessing the clinical results. Though the scoring system employed in the present study is used widely all over the world, it is inadequately described.
| Conclusion|| |
The present study compared the clinico-radiological outcome of two intramedullary implants–PFN and PFNA2 in closed surgical treatment of trochanteric fractures.
- The incidence of intertrochanteric fracture of the femur is common in elder age group
- Trivial trauma was the most common mechanism of injury
- The fracture was more common in females than in males
- Operative treatment by internal fixation allows for early mobilization of patients
- The fluoroscopic exposure time was significantly lower in PFNA2 group
- The duration of surgery was significantly lower in the PFNA2 group
- Radiological union of fractures assessed by the RUSH score at the end of 6 months showed no significant difference between the two groups
- The functional outcome assessed by Harris hip score at the end of 6 months showed no significant difference between the two groups
- Simpler fracture patterns and those with lesser amount of comminution gave better outcomes on treatment.
There was no significant difference between the two groups in terms of clinical or functional outcome. However, fluoroscopic exposure and the duration of surgery were significantly lower with PFNA2. Hence, we conclude that PFNA2 is a better option for the treatment of intertrochanteric fractures of hip.
Ethical clearance was obtained from the institutional ethics committee.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11], [Table 12]