Comparison of PFN (Proximal femoral nail) and DHS (Dynamic hip screw) in treatment of Intertrochanteric femur fractures

Introduction: Intertrochanteric femur fractures are common in the elderly people. The frequency of these fractures has increased primarily due to the increasing life span and more sedentary life style brought on by urbanization. The incidence of Intertrochanteric femur fractures is more in the female population compared to the male due to osteoporosis. Aim and ObjectiveTo compare outcome of intertrochanteric femur fractures treated with DHS and PFN. Methodology: comparative study of proximal femoral nail and dynamic hip screw in the treatment of 50 cases of intertrochanteric femur fractures in the Department of orthopedics, DY Patil Hospital Pune was done from July 2015 to July 2016. Result: Result were almost similar in both groups. Conclusion: It is most difficult task to assess and decide as to which technique is better out the two. Some studies reveal DHS to be better than PFN, while some studies show vice versa. Both the techniques are precise, time tested & require reasonable amount of surgical skill. Final decision depends on operative surgeon’s preference to specific technique.


Introduction
Intertrochanteric femur fractures are common in the old people. Incidence intertrochanteric femur fractures has been raised mainly because of increased in longevity and inactive life style due to advance technology. Cases of Intertrochanteric femur fractures is seen largely in females gender compared to counterpart because of more predisposition of female gender to osteoporosis.
Dynamic hip screw (DHS) or sliding hip screw (SHS) has been routinely use dim plant since long in treatment of Intertrochanteric fractures [1][2][3][4][5]. But, when comparing to intramedullary implants, its having biomechanical disadvantage of more space between the weight bearing axis and the implants [6]. The proximal femoral nail (PFN) introduced by the AO/ASIF group in 1998 is used increasingly to treat intertrochanteric fractures in recent period [7][8][9][10]. Thought

Methodology
This comparative study 50 cases of DHS vs PFN in treatment of intertrochanteric femur fractures was performed at Padmshree Dr D Y Patil medical college and hospital, Pimpri, Pune, and functional outcome was compared in both; DHS and PFN groups with evaluation of postoperative range of movements by Harris hip score.
Choice of Nail Used-Hollow tubular proximal femoral Nail was used which was made up of AISI 316 L stainless steel.
In current research study we utilized nails of same length of 25 mm in all 25 cases. Diameter of proximal portion of nail is 17 mm (proximal 8 cm of nail) and the distal part varying from 9 to 12 mm. Proximal femoral nail ranging from 130 & 135 degree with 10 degree of ante version was used in this study. Antero-posterior radius of this proximal femoral nail is 3000 mm in and 4 degree curve towards lateral. Proximal portion of the nail has slot for fixation for two screws, size of the lag screw 7.9 mm with availability ranging from 55 mm to 115 mm. Proximal one (P1) is of size 6.4 mm and its available in varying lengths ranging from 55mm to 115mm. This is the one which controls the rotation and also known as ANTI ROTATION SCREW. In view of preventing growth in the proximal part of the nail threaded cap is available. To fix distal screws in PFN distal part has two holes. Of these two proximal holes first one also known as derotation screw is for static locking and proximal second screw is for dynamic fixation.
Nail Length Measurement-Our study consisted of use of nails of same size length nail i.e 25 mm in all cases.

Figure-1: Proximal Femoral Nail
Measuring diameter of the nail-Uninvolved side femur radiograph was taken & diameter of canal at the isthmus between both cortexes was measured. We also took help of the ruler provision from the PACS system of x rays which is used in our hospital. By this technique direct measurement of diameter of bone can be made on the computer monitor. However, nails of all sizes were kept ready for operation i.e 9 mm to 12 mm size. Richards dynamic compression screw-Consisting of cannulated lag screw from 19 mm or 29 mm threaded distal portion of 12.7 mm diameter and a proximal no threaded portion (shaft) of 8.7 mm diameter. Richard screw comes in different lengths measuring from 50-110 mm. A 3.2 mm guide wire is used from which Richard screw can be passed. The lag screw is inserted into bone passing through barrel at which it can slide.
There is groove along with length of Richard screw, which guides direction of key in the barrel. This prevents the rotation. The side plate was available in 2-20 holes, which accommodate 4.5 mm cortical bone screws. Usually 4 or 5hole plate were used.

Observations and Results
The following observations were made from the data collected during this Comparison of PFN and DHS in treatment of intertrochanteric femur fractures of 50 cases in the Department of Orthopedics, DY Patil Hospital Pune, from July 2015 to July 2016.
There was almost similar involvement of both genders with maximum patients between 56-60 of age (24%

Discussion
Intertrochanteric femur treatment is challenging fracture by the orthopedic community, not for fixation only, but also for restoration of optimum alignment and function earliest minimizing complications. Surgical fixation permits early rehabilitation and better functional recovery compared to conservative.
Most of patients in present study were from age group of 5th to7th decade of life. Gallaghar et al (1980) reported an eight fold increase introchanteric fractures in men over 80 years and women over 50 years of age [17]. Its because of trochanteric region is the most common site of senile osteoporosis. As hip joint is major weight bearing joint; it gets weak due to continuous abnormal stress of body and trabecular space is enlarged and loaded with fat, and calcaris atrophied. Males to female ratio was 2:1 in both the groups. Higher incidence of trochanteric fractures in males were due to their more active lifestyles. David G. Lovelle found trochanteric fractures more common in women than men by a margin of three to one. Melton J.L., Ilistrup DM, Riggs BL et al reported a female to male ratio of 1.8:1 [18]. Helfenste in (1947) suggested that, by stimulation of osteoclasts due to post-menopausal deficiency of steroid hormone sis responsible for greater osteoporosis. St. Urnier K.M., Dresing K (1995) suggested that pertrochanteric fractures ordinarily appears to women10-15years later than to men [19]. Most of our patients were 50 years and above in them domestic fall (fall at home) and trivial trauma was main reason behind fracture while in road traffic accident (RTA) young patients were affected. This may be attributed to the following factors as enumerated by Cummings and Nevitt in 1994 [21]. Inadequate protective reflexes, to reduce energy off all below a certain critical threshold. Inadequate local shock absorbers e.g. muscle and fat around hip. Inadequate bone strength at the hip on account of osteoporosis or osteomalacia. Horn & Wang stated that mechanism of injury is not direct but due to failure of Stress resisting forces during sudden bending or twisting. A direct blow on the lateral side of thigh would result in contusion, comminution on the lateral surface of the greater trochanter and cause valgus deformity [22].

Original Research Article
External rotation of 15° was noticed in one case operated by proximal femoral nail (PFN) and varus deformity was noted in one case. It might be seen due to early backing out of screws. In 2 cases of varus deformity was seen in the cases operated by DHS. Due to the pull of the muscle the distal shaft fragment has the tendency to migrate upwards thus result in gin varus deformity.In the series by K.D Harrington, out of 72 cases there were 4 cases of coxa vara and 56 cases of limb shortening at an average of 1.5 cms [23].
In his series, shortening was noted in unstable fractures in which Dimon Hughston procedure was done. In the series by Juluru P. Rao of the 124 cases of intertrochanteric fractures, 5 cases of unstable fracture had limb shortening [24].
Average admission time was 21days (3Weeks). According to post-operative pain and general condition patients were made to stand up with walker on 4-5th post-operative day. And then gradually non-weight bearing walking was started within 2-3 days with Walker. In study by B. Mall (30 patients) average ambulation time was 14 days. In the series of Dr. G.S Kulkarni ambulation was usually started after 11-12 days after the stitch removal [25,26].
Average time of union in all our 50 patients was about 16 weeks Assessment of early call us formation at fracture site & its subsequent progress was done with the help of ultrasonography in few cases [27,28]. This was perform edatsubsequent intervalsof 14 th & 28 th post-operative days. Neo vascularization & soft call us in early phases & consolidation of call us was noted in follow up ultrasonographic study.  The patient who was operated by PFN had infection at distal site of suture line. While 2 cases operated by DHS had superficial wound infection at the suture site.It may be because of nutritional deficit and low socio-economic status of patient & mores of tissue exposure, which is more in cases operated by DHS. In the series of patients operated by DHS by Dr.G.S Kulkarni, there were two cases of deep infections which were treated by removal of implant. The infected sinuses thus healed after implant removal. There were 3 cases (15%) of shortening seen in the cases operated by DHS. This shortening ranged from 1-1.5 cms. Patients were given shoe raise which compensated for the necessary shortening. Patients did not have any difficulty later while walking.In the series by Juluru P. Raoof the 124 cases of intertrochanteric fractures, 5 cases of unstable fracture had limb shortening [24].

Original Research Article
The range of movement calculated by the Harris Hip Scoring system treated by both the implants i.e PFN and DHS was good and was almost the same. The range of movements namely flexion, extension, external and internal rotation was good in most cases. The poor result was attributed to associated factors namely along interval between trauma and surgery & development of post operative infection.These fr actures are more commonly seen in elderly people particularly in 5 th to 7 th decades of life [32,33]. Common mechanism of injury is trivial trauma due to fall [14], however in younger patients they are seen These fractures are more commonly seen in elderly people particularlyin5th to 7 th decades of life [32,33].