A prospective comparative study of functional outcome of surgical management of unstable intertrochanteric fractures of femur with dynamic hip screw (DHS) and proximal femoral nailing (PFN) at SMS hospital Jaipur, Rajasthan, India

Sudhir Kumar^1*, Raj Kumar Harshwal², Hemant Bhagat³, Monika Rathore⁴

{¹Associate Professor, ²Assistant Professor, ³Resident, Department of Orthopedics} {⁴Professor, Department of Community Medicine}

SMS Medical College, Jaipur-302004, Rajasthan, INDIA.

Email: drskyadav@rediffmail.com

Abstract         In the present study, we sought to determine outcome of surgical management of unstable intertrochanteric fractures with dynamic hip screw (DHS) and proximal femoral nailing (PFN). This prospective comparative study was carried out on patients admitted in SMS hospital Jaipur between April 2014 to February 2015. Total 80 patients with unstable intertrochanteric fractures were randomly allocated in two treatment groups. 40 patients were treated by DHS and 40 patients were treated by PFN. We looked for length of incision, blood loss, duration of surgery, fluoroscopy timing, union time, any complications and functional outcome. The smaller incision, shorter operative times, relatively less blood loss, less limb shortening and a better overall functional outcome with the PFN indicate that the PFN has advantage over the DHS. However PFN has disadvantage of having more fluoroscopy timing as compared to DHS. There was no statistically difference between union time of fractures in both groups.

Keywords: Intertrochanteric fractures, Dynamic hip screw, Proximal femoral nail.

INTRODUCTION

Trochanteric fractures are one of common injuries sustained in elderly population. Trivial fall being the most common mechanism of injury¹.The goal of treatment is the restoration of the patient to previous status as early as possible. This led to internal fixation of these fractures to reduce complications of prolonged recumbency². The type of implant used has an important influence on complications of fixation. Sliding devices like the dynamic hip screw have been most commonly used for fixation. However, if the patient bears weight early, especially in comminuted fractures, this may lead to implant failure. Intramedullary devices like the proximal femoral nail have been reported to have an advantage in unstable fractures as their placement allowed the implant to lie closure to the mechanical axis of bone, so decrease the lever arm and bending moment on the implant. They can be inserted faster, with less operative blood loss and allow early weight bearing with less resultant shortening on long term follow up. This study was carried out to compare the surgical treatment of unstable intertrochanteric fractures of the femur with the dynamic hip screw (DHS) and proximal femoral nail (PFN) devices, with respect to fluoroscopic time, duration of surgery, blood loss, fracture union and functional outcome.

MATERIAL AND METHODS

This study was conducted in the biggest government tertiary care centre of Rajasthan catering largest number of orthopedics cases. Patients of unstable intertrochanteric fractures admitted in SMS medical college hospital Jaipur between April 2014 to February 2015 were considered for the study. Total 80 patients who met the eligibility criteria out of all 173 patients reported during study period were randomly allocated into two groups using sealed envelope method. Blinding was not done as all the study variables were objective finding.

Inclusion Criteria            

All adult patients (above 18 years of age) with fresh unstable intertrochanteric fractures (type 3 and 4 as per Jensen and Michelson's modification³ of Evans classification) attending SMS medical college hospital and who were able to walk prior to the fracture were included in the study.

Exclusive Criteria

Patients with pathological fractures, patients with bilateral fractures, active infection, unstable medical illness and non-traumatic disorder were excluded from the study. Stable fractures (Type1 and type 2) and open fractures were also excluded. Patients who were unable to walk prior to the fracture were excluded. The patients were evaluated as per the history and mode of injury. Necessary investigations were done. Anterioposterior and lateral radiographs of the affected hip were taken. The patients were then put on skin traction. The fractures were classified as per Jensen and Michealsens³ modification of Evans classification of intertrochanteric fractures. Type 3 and 4 were included in study as these were unstable fractures. Patients were taken up for surgery as soon as possible in routine operation theatre. The fractures were fixed with dynamic hip screw fixation / proximal femoral nailing. Of the 80 patients in the study, 40 were treated with dynamic hip screw fixation (DHS) and 40 with proximal femoral nailing (PFN). Allocation of the fractures to each treatment group was done by random selection.

Group I (DHS): 40 Patients were treated by dynamic hip screw (DHS) by standard technique.

Figure 1: Dynamic hip screw (DHS)

Group II (PFN): 40 Patients were treated by proximal femoral nail (PFN) by standard technique.

Figure 2: Proximal Femoral Nail (PFN)

Adequate blood transfusion and supportive measures were given depending on the preoperative condition of the patient and blood loss during surgery. Type of surgery and detail were noted. Primary study outcomes such as length of incision, duration of surgery, blood loss and fluoroscopy time were recorded during operation. The immediate post-operative x-rays were evaluated. All patients received injectable antibiotics (cephalosporin’s) given one hour before surgery and continued post operatively for 3 days. Oral cephalosporins were continued for next 7 days. Analgesic was initially given in intravenous/intramuscular route for two post-operative days and then orally till pain subsides. Patients were allowed to sit up in bed on the second post-operative day. Static quadriceps exercises were started on the second post-operative day. Sutures were removed after 10 days. Patients were mobilized non-weight bearing as soon as the pain or general condition permitted. Weight bearing was commenced depending upon the stability of the fracture and adequacy of fixation. All the cases were again evaluated through clinical and radiological methods at 6 weeks, 12 weeks, 6 months and 1 year. Check x-rays were taken at every visit to assess fracture union. The fracture union was considered as malunion if varus angulations was greater than 10 degrees.

Evaluation at the final follow up for functional outcome

The final functional outcome was assessed based on Harris Hip Score⁴ (HHS) Modified as follows:

Excellent: HHS between 90-100, Good: HHS between 80-89, Fair: HHS between 70-79, Poor: HHS less than 70

Statistical Analysis

Continuous data were summarized in form of mean and standard deviation, difference in means of two groups were analysed using student's 't' test. Continuous data were expressed in form of percentage. Difference in proportions were analyzed using chi-square test. Level of significance was kept 95% for all statistical analysis.

OBSERVATIONS AND RESULTS

The age of patients ranged from 32-86 years with average being 62.6 years. The most common age group was 61-70 years. 62.5% of the patients were female in this series. Left side is involved in 60% of the patient. The most common mode of injury was trivial fall in 60(75%) patients.

Table 1: Preoperative variables

Table 2: Length of Incision (cm)

Test applied: Unpaired t test, Patient treated with PFN required a significantly smaller skin incision.

Table 3: Duration of surgery (minutes)

Test applied: Unpaired t test, Proximal Femoral Nailing required mean 17 minutes less operative time compared the Dynamic Hip Screw fixation.

Table 4: Blood loss (ml)

Test applied: Unpaired t test, Proximal femoral nail fixation had significantly less intraoperative blood loss as compared Dynamic hip screw.

Table 5: Fluroscopy time (sec)

Test applied: Unpaired t test, Dynamic hip screw fixation required significantly less fluoroscopic time as compared to proximal femoral nail fixation.

Table 6: Complications

*One patient may have more than one complications.

PFN had significantly less complications. Malunion was seen in 25% of the patients in DHS group while there was 5% malunion in the PFN group. Wound infection was seen in 4 (10%) patients in the DHS group and in 2 (5%) patients in the PFN group. 2 (5%) screw back out was seen in DHS.

Table 7: Range of motion of hip joint

Test applied Unpaired t test, There was significantly better mean post operative range of motion in PFN than DHS with 84.25 degree mean in DHS group and 98.75 degree mean in PFN group.

Table 8: Shortening (cm)

Test applied: Unpaired t test, Significantly less limb shortening was seen in the PFN group as compared to the DHS group with a mean of 1.25 cms in the DHS group and 0.57 cms in the PFN group.

Table 9: Time of union

Test applied: Unpaired t test, All the fracture united at a mean of 12.075 weeks. There was no significant difference in time taken to unite the fracture.

Table 10: Final results

Test applied: Chi-square test, χ² = 21.247 with 3 degree of freedom p= 0.000 (S), Excellent to good results were seen in 95% of patient in PFN group and 50% of the patients in DHS group.

DISCUSSION

The goal of the study was to compare the functional outcome of patient with unstable intertrochanteric fractures treated by two different fixation devices, dynamic hip screw (DHS) and proximal femoral nail (PFN). Our study consist of 80 patient with unstable intertrochanteric fractures out of which 40 patient was treated with DHS and 40 with PFN. The age of the patient ranged from 32 to 86 years with an average of 62.6 years. Commonest mode of injury is trivial fall which was noted in 60 (75%) patients. In our study there were 30 (37.5%) males and 50 (62.5%) female showing female are more prone to this fractures. Sex distribution in our study correlated with that of other studies such as Dahl and colleagues⁵, in their study 67% of patients were females, explained by the fact that female are more prone for the osteoporosis after menopause. The mean length of incision in the DHS group was16.15 cm as compared to mean of only 8.1 cm in the PFN group. The smaller incision in the PFN group means that there was less intra operative blood loss. This was comparable to the study conducted by Baumgaertner et al.⁶ The mean duration of surgery in the DHS group was 87.25 minutes. The mean duration of surgery in the PFN group was 69.5 minutes. The difference in the operative time in both groups was found to be highly significant and we attributed this difference to the smaller incisions in the PFN group. Baumgaertner et al⁶ also found that the surgical times were 23% less in PFN group in their series. Saudan and colleagues⁷ found that there was no significant difference between the operative times in the two groups in their series. The fluoroscopy time in the PFN group (average 73.37 seconds) was significantly higher as compared to that of the DHS group (average 57.37 seconds). This was similar to the series by Baumgaertner and associates⁶ who also found a significant difference in the fluoroscopic times in their series, with 70% higher times for the PFN group. However in their study Sauden et al⁷ found no difference between the fluoroscopy times in both the groups. The DHS patients had significantly more blood loss intra-operative compared to PFN group (average 375 /140ml). This is similar to the series by Baumgaertner and associates⁶ who also found a significant difference in the intra operative blood loss in their series, with 44% less blood loss in PFN. There was no significant difference between the two groups with regards to time of fracture union as fracture united at mean 12 weeks in case of DHS and 12.15 weeks in case of PFN. There was statistically significant difference between the two groups regarding malunion. 10 patients (25%) in the DHS group had malunion whereas 2 patient (5%) in the PFN group had malunion. In our series 4 patients of the DHS group had wound infection as compared to 2 patients in the PFN group, which was not statistically significant. In this study the average limb shortening of patient in DHS group was1.25cm as compared to 0.57cm in PFN group which was statistically significant. This could be due to sliding of the lag screw in the DHS group, allowing greater fracture impaction, as compared to the PFN⁸. The average range of motion the hip joint was 84.25 degree in the DHS group and 98.75 degree in the PFN group at final follow up. Hence in our study the patients in the PFN group regained a significantly better range of motion as compared to those in the DHS group (p=0.001). This is contrary to the results put forth by Saudan and colleagues⁷ as they found no statistically difference between the two groups. The overall functional outcome of patient treated with PFN was significantly better compared to DHS (p=0.000). In PFN group 95 % were with excellent and good results as compared with the DHS group which has 50% with excellent and good result. This suggests that use of PFN may be favoured in unstable intertrochanteric fractures when compared to DHS.

CONCLUSION

The smaller incision, shorter operative times, relatively less blood loss, less limb shortening, and a better overall functional outcome with the PFN indicate that the PFN has advantage over the DHS. However PFN has disadvantage of having more fluoroscopy timing as compared to DHS. There was no statistical difference between two methods regarding time of fracture union.

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