Comparison of Second and Third-Generation Nails in the Treatment of Intertrochanteric Fracture : Screws versus Helical Blades

OBJECTIVE
The aim of this study was to compare the radiological and functional outcomes of anti-rotation trochanteric nails (ATNs) with proximal femoral nail anti-rotation (PFNA) in the treatment of intertrochanteric femur fractures in elderly patients.


MATERIALS AND METHODS
In total, 165 intertrochanteric fractures were treated between January 2007 and January 2010. One hundred forty patients were included. The operation time, amount of blood loss, fluoroscopy screening time, and length of hospitalization were recorded. The radiological position of the implant, quality of fracture reduction, and tip-apex distance were evaluated, and the postoperative complications as well as functional condition of the patients were assessed.


RESULTS
There were no significant differences between the ATN and PFNA groups for the presence of general complications, length of hospitalization, and functional capacity. The mean operation time, blood loss amount, and fluoroscopy screening time were more in the ATN group than in the PFNA group. Reoperation was needed for nine and two patients in the ATN and PFNA groups, respectively, because of implant-related complications.


CONCLUSION
Both ATNs and PFNA were suitable for the fixation of intertrochanteric fractures, but the risk of complication occurrence and need for reoperation were found to be higher in patients who were treated with ATNs.


Introduction
Pertrochanteric fractures are common seen in elderly patients, and the incidence of these fractures is expected to increase [1][2][3][4].For stable fracture types, dynamic hip screw systems provide stable fixation with low major complication rates [5].However, high failure rates with the usage of these implants for unstable fracture types have been reported [6][7][8].Intramedullary implants can provide early postoperative weight-bearing ability.A gamma nail was a prototype of cephalomedullary devices.Complications such as cut-out, implant breakage, femoral shaft fractures, and reduction loss have been reported with the use of this device [1,9].To overcome these kinds of mechanical complications, new designs such
as proximal femoral nails (PFNs; Synthes, Solothurn, Switzerland) and anti-rotation trochanteric nails (ATNs; dePuy, Warsaw, IN, USA) were developed.These intramedullary implants provide sliding head-neck screws.However, complications such as lateral migration of head-neck screw, cut-out from headneck fragment, cut-through of the anti-rotation screw into the joint still occurred [10].Proximal femoral nail anti-rotation (PFNA) (PFNA; Synthes, Solothurn, Switzerland) was designed by the AO/ASIF group for improving the rotational stability.It used a single headneck fixation device called a "helical blade".
Until 2008, pertrochanteric fractures were treated with ATNs at our clinic.Subsequently, PFNA was added as a new treatment option.The purpose of this study was to compare the radiological and functional outcomes of elderly patients with pertrochanteric fractures who were treated using PFNA or ATNs.

Material and Methods
The study group comprised 165 patients with low-energy pertrochanteric femoral fractures treated using either ATNs or PFNA between January 2008 and December 2011.Twentyfive patients were excluded due to loss to follow-up and/or death.Therefore, 140 patients were retrospectively evaluated, and patient data were collected from the electronic files of patients.This study ultimately included 71 patients treated using PFNA and 69 patients treated using ATNs.The inclusion criteria were patients who were older than 70 years, patients with a normal mental status (minimental state examination scores between 20 and 30), and patients who did not have associated injuries [11].Patients who had pathological fractures and/or accompanying injuries were not included.The ethics committee approved this study.The Arbeitgemeinschaft für osteosynthesefragen (AO) classification was used to classify fractures.Surgery was performed at the earliest time after the completion of anesthesia consultation.Procedures were performed on a conventional operating table, and patients were positioned in the lateral decubitus position.Reduction in quality and implant positions were confirmed by fluoroscopic images.The fractures were reduced by closed means.All patients were treated by the same three trauma surgeons.The operation time, fluoroscopy screening time, amount of blood loss, and amount of transfused blood units (if necessary) were recorded.Prophylaxis of infection was administered for 2 days and deep venous thrombosis prophylaxis were given postoperatively 35 days.
If the reduction was 5° within the boundaries of the normal collodiaphyseal and anteversion/ retroversion angle, it was classified as "anatomic".Reductions that were within 5°-10° were classified as "acceptable" and those that over than 10° were classified as "poor." The femoral head was divided into superior-central and inferior in the anteroposterior (AP) view and anterior-central and posterior in the lateral view [12].The position of the implants was assessed according to these quadrants.Central or inferior positioning in the AP view and central positioning in the lateral view were accepted as ideal.The tip-apex distance (TAD) was measured according to Baumgaertner et al. [13].Patients were mobilized as soon as possible with weight bearing as they could tolerate Clinical and radiological examinations were performed at the sixth, twelveth-twentyfourth, thirtysixth and fourtyeighth weeks postoperatively.At the final follow-up examination, the Salvati-Wilson scoring system was used to assess daily living activities, ability of self-care, and level of mobility [14].The presence of osteoporosis was evaluated by determining the Singh index of the contralateral hip [15].If this score was under 3, the patient' s hip was accepted as osteoporotic.Statistical Package for Social sciences version 15 (SPSS Inc., Chicago, IL, USA) was used for statistical analysis.Chi-squared test and Student' s t test were used to compare categorical and continuous variables, respectively.p values below 0.05 were accepted to be statistically significant.

Results
The demographic data are shown in Table 1.The patients in the groups had similar mean ages and fracture types.Seventy-one patients (36 males and 35 females) were treated with PFNA, and the mean age of these patients was 80.8±6.4 years.Sixty-nine patients (40 males and 29 females) were treated with ATNs, and the mean age of these patients was 78.4±5.6 years.Perioperative data are shown in Table 2.The mean operation time was longer in the ATN group (51.9±9 min) than the PFNA group (44.7±8 min) (p=0.14).The mean intraoperative blood loss amount was lower in the PFNA group (126.8±49.5 ml) than in the ATN group (162.8±45.6 mL) (p=0.03).Furthermore, the mean fluoroscopy screening time was lower in the PFNA group (38.6±7 s) than in the ATN group (51.6±9 s) (p=0.02).
All fractures were evaluated as healed at the last examination.The mean consolidation time was 14 weeks in the PFNA group and 14.6 weeks in the ATN group (p=0.65).The mean Singh indexes in the PFNA and ATN groups were 2.94 and 2.67, respectively (p=0.07).
In the PFNA group, the quality of reductions was as follows: 54 patients (76.1%) were classified as having good reduction quality, 12 (16.9%)were classified as having acceptable reduction quality, and 5 (7%) were classified as having poor reduction quality.In the ATN group, 50 patients (72.5%)   3).
On average, the TAD in the PFNA group was 21.5 mm for spiral blades, whereas that in the ATN group was 24.5 mm for lag screws.
The Z-effect phenomenon was seen in six patients in the ATN group, four of these had protrusion of the hip pin through the femoral head and were managed with implant removal.The other patients did not have protrusion because the hip pins were quite short.Lateral sliding of the lag screw occurred in three patients.There were two patients with a reverse Z-effect; thus, the removal of antirotational screws was not necessary.Five reoperations were performed because of cut-out.
In three of these cases, revision surgery was performed by partially cemented arthroplasty; in another case, total hip arthroplasty was performed (Figure 1).In one patient, lag and hip screws were because the fracture was considered to be healed.
In the PFNA group, the lateral cortex of the proximal femur (n=3) and greater trochanter (n=1) were fractured during nail insertion but were observed to be healed at the follow-up examination.In this group, two patients needed reoperation.A cut-out was noted in one patient (superior positioning in the AP view).For this fracture, the patient was followed until healing, and the helical blade was removed at four months postoperatively.Follow-up examinations showed a good result for this patient.
In one patient, revision fixation was needed to correct the position of the helical blade.
Fracture shortening because of lateral subsidence of the helical blade was observed in 13 patients; fortunately, revision surgery was not needed for these patients.The overall complications are listed in Table 4.There was no statistically significant difference in the mean Salvati-Wilson hip scores at the final follow-up examination (31.6 and 30.5 for the PFNA and ATN groups, respectively; p=0.12).

Discussion
The incidence of intertrochanteric hip fractures increases as the population ages.Elderly patients have a high risk of developing postoperative complications such as wound infections, pneu-monia, urinary tract infections, and cardiovascular disease [1][2][3].Due to poor bone quality, fracture fixation remains a challenging task in the elderly.Despite the various implants suitable for fixation, the best implant in the treatment of peritrochanteric fractures is not yet clear [16,17].Our study revealed that both ATNs and PFNA are reliable devices for the surgical management of intertrochanteric fractures in elderly patients with high union rate, less blood loss, and fewer postoperative complication rates.Additionally, complication rates and the risk of secondary operation were higher in patients treated using ATNs.
The literature suggests that PFN is a reliable method for the treatment of peritrochanteric femur fractures.However, technical complications such as cut-out and the Z effect of locking screws of proximal fixation have been reported in the literature [10].PFNA was designed to simplify the technique and decrease these kind of technical complications.The replacement of column screws with a helical blade augments the contact surface area between the purchaseholding device and the cancellous bone of the femoral head [18][19][20][21].Stability increase in fracture fixation and remarkably higher rotation torques have been shown in biomechanical studies with the helical blade system [22][23][24][25].
For the implantation of ATNs, drilling in the femoral head is required, and this procedure results in the loss of useful bone tissue.In contrast, for PFNA, less drilling is required for the blade, and there are fewer bone defects as the blade only needs to be impacted into the cancellous bone.
Gardenbroek et al. [26] surprisingly concluded that the PFNA system was not advantageous for achieving rotational stability of the head-neck fragment compared with PFN.However, the authors reported that secondary complication rates were higher in the PFN group.Park et al. [27] showed that PFNA yielded better outcomes than screw proximal nails with regard to functionality and complications.Lenich et al.
[10] compared second-and third-generation intramedullary devices in trochanteric fractures and reported an advantage of third-generation implants (PFNA, Gleitnagel, and TFNs) over second-generation PFN implants, in terms of complication rates and suitability for osteoporotic bone tissue.In our study, we detected no remarkable differences between the ATN and PFNA groups based on general complications such as length of hospitalization and functional capacity.However, the mean operation time, blood loss amount, and fluoroscopy time were noticed to be longer in the ATN group.The lateral decubitus position, in which nail insertion is easier, was our preferred position in these patients.Reduction was maintained by applying traction to the long axis of the injured limb, which was applied by an assistant surgeon.
A major disadvantage of the lateral decubitus position is the risk of the loss of reduction during fluoroscopic imaging, particularly in severe osteoporotic unstable fractures.This is because a single guidewire cannot achieve sufficient temporary fixation while changing the hip position from the AP view to the frog leg position.Alternatively, with ATNs, double guidewires are more stable for reduction safety while moving the hip between the AP view and frog leg position.
A femoral fracture which is located around the tip of the nail is a reported complication, particularly in shorter patients [28].Yaozeng et al. [28] reported this complication in six patients (5.6%).However, we did not observe any typical femoral shaft fracture perioperatively in the ATN and PFNA groups.
Zhang et al. [29] compared the clinical results of second-and third-generation implants in the treatment of intertrochanteric fractures, and they claimed that no significant difference existed in final functional outcomes.In our study, the mean functional scores and ability to return to preinjury functional levels were similar in both groups.Regardless of the choice of implant, the fracture type and patient' s general condition may influence the functional outcomes.
In our study, 72% of the patients had thigh or hip pain, but this did not affect the functional outcomes.Yaozeng et al. [28] showed that 90.1% of patients complained of hip and thigh pain; they claimed that the gluteus medius tendon can be damaged during nail insertion and that this could be a potential cause of postoperative hip and thigh pain.
There were no substantial differences in the position of the blade/screw between the two groups in terms of the quadrant of the headneck fixation device.When we analyzed our five cutout cases, we noticed that all these patients had unstable trochanteric fractures with comminution of the medial cortex.In two cases, screws were in the anterior-superior position, whereas in the other three cases, they were in ideal positions.The cutout rate of ATN was 7%, and this is not above the average shown in other studies.In contrast to ATNs, the complication rate of PFNA was lower (2%).
The present study has several limitations.First, the design of the study was retrospective; therefore, follow-up with control X-rays after a period of time was not possible in all patients.
Another limitation was the relatively small patient groups.
Both ATNs and PFNA are reliable devices for the treatment of intertrochanteric fractures in elderly patients; they both have high union rates, less blood loss, and lower postoperative complication rates.However, the complication rates and risk of secondary operations were higher in patients treated using ATNs.An important point in achieving good results and avoiding cutout complications in trochanteric fractures is to avoid varus reduction and anterior-superior blade or screw position.

Figure 1 .
Figure 1.a-e.(a) Preoperative AP view displaying an AO/ASIF type 31-A2.2intertrochanteric fracture, (b, c) early postoperative AP and lateral views, early postoperative AP and lateral views, (d) X-ray showing the protrusion of hip pin and anti-rotation screw into the hip joint, (e) total hip arthroplasty performed as a salvage procedure.

Table 1 .
Demographic data

Table 3 .
Comparison of radiographic evaluation results between the two groups

Table 4 .
Complications between the two groups