Implant-Related Complications Following Proximal Femoral Nail Antirotation (PFNA) in Unstable Intertrochanteric Fractures – Early Follow Up

INTRODUCTION: Intertrochanteric fractures present in a wide variety of patterns that range from simple to complex and may be minimally displaced or widely displaced. Unstable intertrochanteric fracture can fail due to mechanical problems, including loss of fixation, re fracture, or implant failure. PURPOSE: The aim of this study was to analyse the failures in patients with unstable intertrochanteric femur fractures treated with Proximal Femoral nail Antirotation (Synthes). METHODS: A retrospective analysis of 97 patients with unstable intertrochanteric factures (AO: 31A2: n = 65 / 67.01 %; 31A3: a Proximal femoral nail Antirotation (PFNA) a self-contained District general hospital was conducted. RESULTS: Study included 25 (26%) Males and 72 (74%) Females with mean age of 82 years. Study period over was 12 months with mean follow up 15 months (range 6 to 18 months). Intraoperative and Postoperative radiographs showed good reduction in 80, acceptable in 12 and 3 were deemed suboptimal. 20 patients had implant related complications. Consequently 10 patients (10.5 %) had to undergo revision surgery. Reasons of revision; Implant failures = 8 (8.4%) all were revised; Helical Blade backing out more than 1 cm = 9, only one ( 1.05 %) revised) and Greater trochanter splintering = 3 only 1 (1.05%) required revision. CONCLUSION: Implant related complications requiring revision occured in 10.5 % (10) in early term follow up. Of those requiring revision 6 patients had highly unstable 31 A2.3 type fracture. Our study reinforces high failures in unstable intertrochantric fractures. Though Ideal implant remains elusive but Optimum intraoperative reduction and use of augments should be considered to improve outcomes.


INTRODUCTION
Intertrochanteric account for approximately 50% of all fractures in the proximal femur. These fractures occur mainly in elderly patients with osteoporosis and are a result of low-energy trauma and cause severe disability in such patients [1] . Hagino et al. reported that individuals above 50 years of age have a lifetime risk of hip fractures and the incidence is 5.6% for men and 20% for women [2] . The challenging goal in management of Unstable trochanteric Fractures is to achieve anatomical reduction with a stable fracture fixation, with International Journal of Orthopaedics low morbidity and early mobilization. No implant is universally fit for these fractures and the best method of surgical fixation remains debatable.

Implant-Related Complications Following Proximal Femoral Nail Antirotation (PFNA) in Unstable Intertrochanteric Fractures -Early Follow Up
The Intramedullary nail (PFNA -Synthes ) provides an intramedullary construct with the advantages of a reduced level arm compared to extra medullary fixation. Several studies reported highfailure rates associated with this implant, such as implant failure, secondary. Varus collapse and screw cut-out. To prevent these complications, the importance of anatomical reduction and medial calcar support to prevent secondary Varus collapse and implant failure has been outlined [3][4][5][6][7][8][9][10] . Fixation of proximal femoral fractures especially in old with osteoporosis remains a challenge. The cervical, trochanteric, and sub trochanteric fractures at all three levels in proximal femur increase with age and are greater for women than men [11] .
The aim of this study was to assess the reasons of revision in unstable intertrochanteric fractures treated with PFNA.

MATERIALS AND METHODS
We conducted a retrospective analysis of patients who underwent Proximal femur Nail Anti-rotation (Synthes) fixation for an unstable intertrochanteric fracture in our centre over a twelve months period. Radiographs of 156 patients were analysed for the type of fracture, the time to union, mechanical failures and for any revision procedures. Fractures were classified according to Arbeitsgemeinschaft fu¨r Osteosynthesefragen (AO), Figure 1 [19] .
Fracture union was defined as radiological signs of fracture healing in three out of four cortices in conventional radiography or consolidation in computed tomography. Delayed-union was defined as missing radiological fracture healing after 6 months or no progressive signs of fracture healing in between the three-and 6-month controls. Other measurements were demographic data; age, gender and the grade of surgeon operating.
Inclusion criteria were the presence of unstable intertrochanteric fractures; 31 A2 and 31 A3 in patients over 65 years with no additional ipsilateral fracture. A sufficient follow-up was fulfilled when there were follow up radiographs available for review. Patients with stable Intertrochanteric fractures (AO 31 A1), pathological fractures, periprosthetic fractures (n = 44) were excluded from the study, figure 1, 17 patient with no follow up x rays were excluded as well. Total of 97 patients fulfilled the criteria and were included in the study. Patient's data were acquired from electronic patient's charting system. Mean follow-up was 15 months, ranging from 4 months to 18 months.

RESULTS
20 patients had implant related complications. Consequently 10 patients ( 10.5 %) had to undergo revision surgery. 8 patients (8.4%) had Implant related failures (Table 1); Helical blade cut out in three, Helical blade backed out more than 1 cm one, Implant fracture one, Migration of nail one, Peri prosthetic fracture one, and distal screw breakage broke in one. In 9 cases Helical Blade backed out more than 1 cm; only one (1.05% ) was revised for impingement symptoms. 3 patients had Greater trochanter splintering and only 1 (1.05%) required revision, the splintering of greater trochanter was present pre operatively. One patient was revised due to malposition of the implant purely due to deficient technique. All implant failure had reoperations between 3 days to 4 months post index operation. The most common mechanical complication was the backing out or lateral migration of the helical blade, however only one patient is this  group had to be revised.
There was no case of non-union in our series, but three cases showed delayed union with Varus collapse.
All the revised cases had suboptimal intraop reduction of fracture and or suboptimal placement of the Helical blade. There was no difference in revision rate whether the index procedure was carried CONCLUSIONS When fixing fractures with intramedullary nailing systems, achieving anatomic reduction and a perfect implant positioning is key to allow immediate full weight bearing and minimise risk of cutout, non-union and implant failure 8in unstable intertrochanteric fractures. Cerclage wires as an augmentation may be considered to get anatomical reduction and support to posteromedial and greater trochanteric comminution.

DISCUSSION
Unstable trochanteric fractures are considered to have one or more of the following configurations; posteromedial comminution, reverse obliquity, sub trochanteric extension, IT fractures with avulsed greater trochanter and lateral wall breach. Intramedullary devices have an advantage of load sharing with smaller bending moments allowing early weight bearing and preventing excessive collapse [12] . The medial and posteromedial fracture fragments have been considered to be important elements in determining the severity of intertrochanteric hip fracture [13] . unstable intertrochanteric fractures usually accompanied by poor bone quality have high failure rates, ranging from 18% to 56% [14][15] The ideal implant to choose to fix unstable trochanteric fractures remains elusive and is a topic of debate with proponents of the various implants, each claiming advantages over the other methods [16] . The failure rates of these unstable fractures fixed with sliding hip screws averages approximately 6-32% [6][7][8][9][10] . Intramedullary devices, such as the gamma nail (GN) and proximal femoral nail (PFN) have some theoretical advantage over the DHS. However, gamma nail (GN) has a failure rate ranging from 12.7% to 15% in various studies [17][18][19][20][21][22] . As for PFN, Fogagnolo et al. found that the intraoperative technical or mechanical complication rate is as high as 23.4% [23] . In unstable intertrochanteric fractures CMN demonstrated significantly reduced failure and collapse rates when compared to SHS [24] .
Apel et al. showed that in unstable intertrochanteric femoral fractures, the fixation of large and small posteromedial bone fragments increased the mechanical stability by 57% and 17%, respectively while there was no general consensus regarding when to use cerclage wires or screws [25] .
In our study, we evaluated the outcome of the patients, and the fracture healing and related complications arising from the intramedullary construct in unstable introchanteric fractures. Our results showed 20 patients had implant related complications. Consequently 10 patients (10.5%) had to undergo revision surgery. The revised cases had suboptimal intraop reduction of fracture and or suboptimal placement of the Helical blade. To maintain the reduction achieved intraoperatively, the decision to use an adjunct like cerclage wiring or loop may be considered. A better implant does not compensate for an inadequate surgical approach or deficient surgical techniques which are paramount for successful treatment There was no difference in revision rate whether the index procedure was carried out by consultant or middle grade surgeon.
The mechanical complication following unstable intertrochanteric fracture remains high. Our findings are corroborated by The (AO -PFNA study group) leading to (8.8%) unplanned re-operation [26] .