Management of complex intertrochanteric fractures of the femur in elderly patients – dynamic hip screws or proximal femoral nails or arthroplasty

INTRODUCTION

Fractures around hip joint are one of the commonest injuries sustained by the aged, predominantly in patients over 60 years of age. The goal of treatment of an intertrochanteric fracture must be restoration of the patient to his or her pre-injury status at the earliest possible time. 45% of all hip fractures are intertrochanteric fractures and 35–40% of these fractures is unstable three or four part fractures and associated with high rates of morbidity and mortality. Due to difficulty in obtaining anatomical reduction, management of the unstable intertrochanteric fractures in elderly patients is challenging and controversial. Osteoporosis and instability are the most important factors preventing early weight bearing and leading to unsatisfactory results in these cases. Complications such as excessive sliding (leading to shortening), varus displacement, nail pull-out, and/or screw breakage are some of the problems commonly seen in these osteoporotic patients who had been treated by dynamic hip screw (DHS).^1,2 Although this implant is the standard treatment for unstable intertrochanteric fractures, it is associated with high rate of complications and morbidity, and therefore primary hip arthroplasty was also suggested as an alternative treatment by some authors.^2-4 In addition, DHS is not usually recommended in unstable reverse oblique fractures.^2,5,6

Intramedullary devices like the proximal femoral nail have been reported to have an advantage in such fractures as their placement allowed the implant to lie closer to the mechanical axis of the extremity, thereby decrease the lever arm and bending moment on the implant. They can also be inserted faster, with less operative blood loss and allow early weight bearing with less resultant shortening on long term follow up.

Biomechanical studies have shown that intramedullary devices are more stable under loading, although associated with more reoperation rates as shown in few studies. Furthermore, the tip of the nail was redesigned to decrease the risk of intra and post-operative fractures of the femoral shaft by a significant reduction in bone stress.

Hence the present study was done at our tertiary care centre to compare the functional outcome of unstable intertrochanteric fractures treated randomly with proximal femoral nail (PFN) v/s dynamic hip screw (DHS) v/s bipolar hemiarthroplsty using Harris hip score (HHS) and to evaluate the advantages, disadvantages and complications associated with fixation of unstable intertrochanteric fractures with proximal femur nailing and dynamic hip screw.

METHODS

The prospective study was conducted in a tertiary institute by collecting data of 90 cases of unstable and complex intertrochanteric fracture who have undergone proximal femur nail and dynamic hip screw randomly at tertiary hospital from December 2014 to April 2016 and followed up till next 6 months postoperatively. The study started after Institutional Ethics Committee approval.

Surgically fit post-traumatic patients more than 70 years of age who has been diagnosed as having complex/unstable intertrochanteric fractures which include postero medial large separate fragmentation, basicervical patterns, reverse obliquity, displaced greater trochanteric fractures and failure to reduce fracture before fixation or with sub-trochanteric extension were included in study. Patients with following conditions were excluded viz., patients who had less than 6 months of follow-up, bilateral fractures, pathological or compound fractures, fractures associated with polytrauma, pre-existing femoral deformity preventing hip screw osteosynthesis or intra-medullary nailing and sub-trochanteric fractures, fractures extending 5 cm distal to the inferior border of the lesser trochanter.

Clinical and radiological assessment as per the patient proforma done for comparison in terms of

• • Union defined as appearance of bridging callus and disappearance of fracture line.
• • On postop follow-up neck-shaft angle will be calculated and variations will be noted after same post op mobility protocol was followed for both group of patients.
• • Limb length discrepancy will be measured.
• • Any intraoperative or postoperative blood transfusion will be noted.
• • Any complications if any arise during follow up will be noted viz., early- intraoperative blood loss, immediate postoperative blood transfusions, infection, late infection, hip pain, readmission, screw cut out, varus collapse.

Statistical analysis

After the data regarding mentioned variables was procured preoperatively and postoperatively, it was tabulated and analyzed. Data were statistically described in terms of mean (±SD), frequencies (number of cases) and percentages when appropriate. Pre and post comparison of ordinal data was done using Wilcoxon’s sign rank test while Fisher’s exact test, chi-square test were used for comparing qualitative variables. A probability value (p value) less than 0.05 was considered statistically significant. All statistical calculations were done using SPSS (Statistical Package for the Social Science; SPSS Inc., chicago, IL, USA) version 20.

RESULTS

In the study of total 90 cases of unstable and comminuted peritrochanteric fractures, according to AO classification, 15 patients were 31A2.2 type while number of 53 and 22 patients was included in 31A2.3 and 31A3.1 type (Table 1). Each group included 30 patients. Among them, 3 cases (3%) showed failure of union among them 2 patients underwent DHS while one underwent PFN fixation. 73 cases went well without any complication while 5 cases with DHS screw cut-out among them 2 underwent non-union, 3 cases with Z-effect in PFN fixation (Figure 1-4). Total number of 6 cases (6.6) had infection, 3 of them underwent DHS fixation while 3 patients underwent bipolar hemiarthroplasty (Table 2).

Complications and their distribution including shortening and need for blood transfusion in each group is mentioned below (Table 3-5). It suggest that DHS fixation has more rate of complications (26.6%) than other two while requirement of blood transfusion is most in bipolar group.

Fisher’s exact value p=0.244 (non-significant).

Chi sq =10.769; df =1; p=0.002 (highly significant)

At 6 weeks-mean score in PFN was higher 45.4 as compared to 39.5 in DHS group and 76.8 in bipolar group. At 6 months-mean score in PFN, DHS, bipolar groups were 90.3, 81.6, 92.4 respectively (Table 6 and 7).

Fisher’s exact value p=0.356 (non-significant).

t =10.972; df =68.

t =7.702; df =68

DISCUSSION

Majority of these fractures were caused by domestic fall. We have used AO classification in series because it appears to be more descriptive. In our study in DHS group maximum patients were of AO type 31-2.3 which was 58.8% of the total (Table 1). In our study there was 1 case of fixation failure in PFN group due to poor technical performance. 3 cases of Z effect due to longer proximal cannulated cancellous screws. Cases of Z effect were managed conservatively with protected weight bearing and fracture united. In DHS group there were 5 cases screw cut out, all were revised with hemiarthroplasty as they were of >65 years old. Hence failure rate seen more with DHS as compared to PFN requiring revision surgeries.

Several authors reported on the complication of femoral shaft fracture with intramedullary nail and recommended against its use but in our study no such complication occurred. Complication rate is seen to be higher in DHS then PFN and bipolar but is not statistically significant.

In this study shortening was found in 11.5% patients in DHS group and in 2.86% patients in PFN group. Considering the fact that additional surgical exposure can theoretically prolong the operative time and thus the blood loss in DHS than PFN it can also be noted that in our study, history of blood transfusion post operatively in DHS group the p value for which was significant according to Pearson’s chi-square test with p value 0.004.

All the patients were subjected to Harris hip score at 6 weeks and 6 months. At 6 weeks, HHS mean score is considerable high bipolar group suggestive of excellent early pain relief with bipolar compared to fixation methods. At 6 months-mean score in PFN, DHS, bipolar groups were 90.3, 81.6, 92.4 respectively. This suggested long-term HHS-score is equivocal in all methods with highest in bipolar group.

Bridle and associates prospectively compared fixation of 100 intertrochanteric fractures treated randomly by either dynamic hip screw or intra medullary device like the proximal femoral nail and found no difference in operating time, blood loss, wound complications and final mobility.⁷ In their study cut-out occurred in 3 cases with DHS and in 2 cases with intramedullary device. However 4 cases of fracture femur occurred close to the tip of the intramedullary device.

No difference was found in the outcomes comparing stable and unstable fracture patterns in a series by Adams et al and they reported that only 21% of their 197 patients regained their pre-fracture independence. ⁸

Sudan and associates showed that there was no statistically significant difference intraoperatively, radiologically or clinically between patients treated with dynamic hip screw or intramedullary hip screw in their study of 206 patients as shown in Table 8.⁹

According to Ahrengart and associates, intramedullary device more frequently preserved the fracture position obtained pre-operatively.¹¹ They also concluded that in the less communited fractures the compression hip screw method was the preferred method of treatment whereas the intramedullary nail was an alternative treatment for more communited fractures.

In 2010 a study by Sancheti et al, concluded that hemiarthroplasty for unstable osteoporotic inter-trochanteric fractures in elderly results in early ambulation and good functional results.¹² Findings in our study supports bipolar hemiarthroplasty as good alternative in elderly patients.

CONCLUSION

The PFN group and bipolar group in our study performed much better in view of union rates, complications, blood transfusion and functional outcome based on HHS than the DHS group. Our conclusion from our study supports the use of PFN for unstable and complex intertrochanteric fracture femur with lesser failure rates, lesser blood loss, less shortening, early union, less revision surgery and better functional outcome. However, during implantation of PFN a more precise technical performance is required for better outcome. However, extremely osteoporotic patients or extreme comminution at fracture site favours bipolar hemiarthroplasty in elderly patients.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: The study was approved by the institutional ethics committee

REFERENCES

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