Introduction

Fractures around the trochanteric region of femur are one of the commonest fractures encountered in orthopaedics and also the most devastating injuries of the elderly. The incidence of this fracture increases with advancing age.

These pertrochanteric femoral fractures especially in elderly have the high postoperative fatality rate and have become a serious health resource issue because of the high cost of care, prolonged morbidity and extensive disability unless the treatment is appropriate [1].

Better understanding of the biomechanics and the development of better implants have led to radical changes in treatment modalities of pertrochanteric fracture femur which can be treated with either a sliding hip screw or a trochanteric nail.

A problem with sliding hip screws is collapse of the femoral neck, leading to loss of hip offset and shortening of the leg. Although some such sliding is expected, too much shortening is detrimental to hip function. Therefore, Proximal Femoral Nail was designed in 1996 which gives a further advantage of minimally invasive surgery [1].

This study was therefore undertaken for evaluating the results of Proximal Femoral Nail in the management of pertrochanteric fractures by analysing the factors which influence the post-operative mobility, associated complications and functional outcome.

Material and Methods

This prospective study was done at our centre in 50 cases of pertrochanteric fracture treated with PFN between 2014 to 2016 after written informed consent and clearance from institutional ethical committee.

Patients with pertrochanteric fractures, with age more than 20 years and fit for surgery were included in the study, whereas skeletally immature individual, open or pathological fractures were excluded from the study.

After obtained medical clearance, all patients were operated under the same spinal anesthesia on fracture table. Primarily closed reduction was obtained and under c arm reduction was checked in AP and lateral views on the fracture table.

except for 5 patients, in which manipulation / elevation or compression with help of the bone spike was done. The mean surgical time was 71 min (range 63 to 110 min).

The mean blood loss in surgery was 180 ml (range 150 to 300 ml). Union was achieved in all patients in mean 12.02 weeks (range 10 to 14 weeks).

The mean Harris Hip Score at final follow up of 6 months in 47 patients was 84.32 ± 5.55. 32 (68%) patients had good outcome, 7 (14%) reported with excellent outcome and 5 (10%) had a fair outcome. Only 4 (8%) patient had poor outcome (Figure 1).

There was an statistically significant improving trend in the Harris hip score from 1 month, 3 months to 6 months which was 37.68 ± 5.42, 70.83 ± 5.06 and 84.32 ± 5.55 respectively.

Majority of the patients (74.46%) had either no pain or slight pain which did not affect their activities.Only one patient had severe pain and 19.1% (9) of patients had mild to moderate pain which was relieved with analgesics.

41 patients (86 %) had no or slight limp that did not affect their activities. 6 patient (12.8%) had moderate limp which was mainly due to shortening.

51% patients did not require any support for walking and 25.5% of patients used cane for only long walks, whereas only 2 patients was mobilizing with the help of crutch. 87.2% patient was able to walk outdoor. Only 10.6 % patients walk in indoor area. One patient was not able to walk and stay in bed & chair. 38.29% of patients could climb stairs without any support but 46.8% required the support of railing.

3 patients were unable to climb the stairs. Squatting was possible in 29.8% with ease and with difficulty in 48.9%. 10 patients were not able to squat. Cross leg sitting was possible in 78.7% of the patients, but 48.9% of these patients had some difficulty while doing so.

10 elderly patients were unable to sit cross legged. This restriction of motion was primarily due to osteoarthritis. Of the 47 patients in this series, 1 patient had shortening of more than 2 cm which required shoe raise. 3 patients had less than 2 cm of shortening and it did not require any treatment, whereas rest had no LLD.

Most common complications was shortening seen in 4 (8% cases), whereas varus, superficial infection and screw cut out was seen in one patients respectively, while Z effect and abductor lurch was seen in two patients each (table 1).

Discussion

The successful treatment of Pertrochanteric fractures depends on many factors like age of the patient, patient’s general health and comorbidities, time from fracture to treatment, adequacy of treatment and stability of the fixation.

Current recommendations suggest that all pertrochanteric fractures should be internally fixed to reduce the morbidity and the mortality of the patient. But the appropriate method and the ideal implant by which to fix the pertrochanteric fracture is still in debate [1].

Several fixation devices have been developed to overcome the difficulties encountered in the treatment of unstable trochanteric fractures. Until recently most of these fractures were treated by sliding hip screw.

Since these devices performed less well in unstable trochanteric fractures with high rates of failure, intra medullary devices have become increasingly popular.

The proximal femoral nail is an effective load sharing device that incorporates the principles and theoretical advantages of all the intra medullary devices [3].

Biomechanically, PFN is better as it is stiffer; it has a shorter lever arm (i.e. from the tip of the lag screw to the center of the femoral canal) whereas the DHS has a longer lever arm (i.e. from the tip of the lag screw to the lateral cortex).

The DHS with a longer lever arm undergoes significant stress on weight bearing and hence higher incidence of lag screw cut out and varus malunion [4].

PFN can be done closed, which provided advantages of minimal blood loss, shorter operative time and early weight. PFN provides a dynamic femoral neck screw and splints whole of the femer [5].

We evaluated the outcome of PFN in 50 patients of pertrochanteric fracture and found excellent to good outcome in 39 (78%) cases, whereas poor outcome in 4 (8%) cases with mean Harris Hip Score at final follow up of 84.32 ± 5.55.

whereas Saudan et al concluded no advantage of intramedullary nail over sliding compression hip screw for low-energy pertrochanteric fractures [8].

Kumar et al and Bhakatet et al concluded that DHS was tolerated better by young patients with stable fracture while PFN had a better outcome with osteoporotic patients and weak bone mass and reverse oblique fractures.

PFN group has less blood loss and less operating time compared to DHS group. In the long term both the implant had almost similar functional outcomes [10,11].

Whereas Huang et al in his meta-analysis concluded that PFN fixation shows the same effectiveness as DHS fixation with respect to operation time, blood transfusion, hospital stay, wound complications, number of reoperation, and mortality rate [12].

We found proximal femoral nail to be more useful in unstable and reverse oblique patterns due to the fact that it has better axial telescoping and rotational stability. It has shown to be more biomechanically stronger because they can withstand higher static and several fold higher cyclical loading.

So the fracture heals without the primary restoration of the medial support. The implant compensates for the function of the medial column. Intramedullary proximal femoral nail also acts as a buttress in preventing the medialization of the shaft.

Also, proximal femoral nail is long and it has smaller diameter at the tip which reduces the stress concentration at the tip. Hip screw and the anti-rotation cervical screw of the Proximal femoral nail adequately compress the fracture, leaving between them adequate bone block for further revision, if need arise.

We in our study found success of Proximal femoral nail depends on good surgical technique, proper instrumentation and good C-arm visualization and it had advantages of easy reduction with traction, lesser assistance, easy patient manipulation and better C arm visibility.

Proximal femoral nail is costly than the dynamic hip screw, but it provided advantages like less operative time, lower blood loss, lesser hospital stay and lesser medications as minimal invasive, thus reducing the overall cost and early return to daily activities.