|Year : 2015 | Volume
| Issue : 1 | Page : 21-26
Comparison of outcome of management of unstable pertrochanteric femoral fractures with dynamic hip screw and proximal femoral nail
Hemant Sharma, Deepinder Singh Loomba
Department of Orthopaedics, Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar, Punjab, India
|Date of Web Publication||19-Nov-2015|
Dr. Hemant Sharma
390, Shastri Nagar, Back Side Police Lines, Amritsar, Punjab
Source of Support: None, Conflict of Interest: None
Context: Pertrochanteric fractures of the proximal femur are a common occurrence among elderly patients. The two types of implants most commonly used for internal fixation of these fractures are dynamic hip screw (DHS) and proximal femoral nail (PFN). However, limited data exist showing comparison between these implants for the treatment of unstable pertrochanteric fractures which are more difficult to manage than the stable ones.
Aims: The purpose of this study was to compare the outcome of management between both implants in the treatment of pertrochanteric fractures.
Settings and Design: It is a prospective study done at Sri Guru Ram Das Institute of Medical Sciences. Amritsar (Punjab), India.
Materials and Methods: Totally, 30 cases of unstable pertrochanteric fractures (Arbeitsgemeinschaft für Osteosynthesefragen [AO] type 31A2 and 31A3) were included and treated using PFN and DHS (15 cases each) from July 2011 to June 2013. Alternate allocation to each implant group was done. Follow-up was for about 6 months. Results were obtained with regard to operation time, blood loss, fluoroscopy, time to union, time to full weight bearing, and the requirement for revision surgery. Functional scoring was done using the Salvati and Wilson hip score.
Statistical Analysis Used: Clinical and radiological data were analyzed using the statistical software epi-info version 3.5.1 released in August 2008.
Results: Patients who underwent fixation by PFN had a shorter operation time, lesser blood loss, and returned to full weight bearing earlier than those who had DHS. However, more fluoroscopic exposure was recorded in PFN than DHS. Time to union was more or less the same. Patients who underwent PFN fixation had better Salvati and Wilson hip scores than those with DHS.
Conclusions: In unstable pertrochanteric fractures, PFN definitely holds an edge over DHS.
Keywords: Dynamic hip screw, pertrochanteric fractures, proximal femoral nail, unstable
|How to cite this article:|
Sharma H, Loomba DS. Comparison of outcome of management of unstable pertrochanteric femoral fractures with dynamic hip screw and proximal femoral nail. Afr J Trauma 2015;4:21-6
|How to cite this URL:|
Sharma H, Loomba DS. Comparison of outcome of management of unstable pertrochanteric femoral fractures with dynamic hip screw and proximal femoral nail. Afr J Trauma [serial online] 2015 [cited 2020 Jun 5];4:21-6. Available from: http://www.afrjtrauma.com/text.asp?2015/4/1/21/162236
| Introduction|| |
Pertrochanteric area includes the part of the femur from the extracapsular part of the neck to a point 5 cm distal to the lesser trochanter. It can be divided into the intertrochanteric area which is between the greater and lesser trochanter of the femur and the subtrochanteric area which is below the lesser trochanter. Weight-bearing stress is an unequally distributed force throughout this area. Koch determined that the weight bearing force is 1200 pounds per square inch in the femur (in a 200 pound man) and is more in the medial cortex than in the lateral cortex. Medial communition therefore influences stability of fracture fragments and treatment outcomes.
Pertrochanteric fractures are one of the most commonly encountered fractures in clinical practice and can account for nearly 40% of admissions in most orthopedic wards. These fractures occur predominantly in people over 60 years of age and are 3–4 times more common in women than in men.
Evans made an important contribution to knowledge about stability of these fractures. According to them, in stable fracture patterns, the posteromedial cortex remains intact or has minimal communition making it possible to obtain stable reduction. Unstable fractures, on the other hand, are characterized by a greater communition of the posteromedial cortex.,
Most surgeons prefer classifying these fractures simply as stable and unstable.
ArbeitsgemeinschaftfürOsteosynthesefragen (AO)/Orthopaedic Trauma Association (OTA) classification of proximal femoral fractures is best describes the stability of the fractures.
About 50% of these fractures are unstable. The results of management of unstable fractures are less reliable and have a high failure rate of 8–25%. One goal of operative treatment is strong, stable fixation of the fracture fragments. Unstable fractures are technically much more challenging to manage than stable fractures. A stable reduction of this type of fractures requires providing medial and posterior cortical contact between the major proximal and distal fragments to resist varus and posterior displacing forces.
Hence, surgeons must understand implant options available and should strive to achieve accurate realignment and proper implant placement.
Until recently, most of these fractures were treated by a sliding hip screw system also known as the dynamic hip screw (DHS). Since this device did not perform so well in unstable trochanteric fractures, proximal femoral nails (PFNs) were developed combining the features of an unreamed intramedullary femoral nail with a sliding, load-bearing, femoral neck screw.
The essence of the study is to find out whether the newer implant (PFN) holds any advantage over the classical one (DHS) through comparison of various intraoperative, postoperative, and functional variables.
Aims and objectives
To assess and compare the functional outcome of DHS and PFN for fixation of unstable pertrochanteric fractures (AO/OTA type 31-A2 or type 31-A3).
| Materials and Methods|| |
The present study was conducted on 30 patients with unstable pertrochanteric fractures who were managed during the study period. These unstable femoral fractures as per AO/OTA classification  were treated with DHS or PFN (fifteen with each implant). Of the 30 patients, 19 were AO/OTA type 31-A2 and 11 were AO/OTA type 31-A3. Randomization was done by alternate allocation to each fixation method as the patients presented. Eventually, of the 19 patients with 31-A2 fractures, 10 had DHS, and nine had PFN while for the 11 patients with 31-A3 fractures, five had DHS, and six had PFN. Patients of all age groups with unstable pertrochanteric fractures of the femur were included in the study after institutional ethical clearance. Patients who were unable to walk before injury; those with pathological fractures; those with previous ipsilateral hip or femur surgery and those with fracture extension past the subtrochanteric area were all excluded from the study. Informed consent was taken from all patients.
Type of anesthesia to be used was decided by the anesthesiologist. All cases were done under spinal anesthesia with 2 cases having additional epidural top-ups. Following standard operative procedure for skin preparation and draping of the patient, DHS or PFN was applied as per standard method done by surgeons with similar qualification (Masters' degree) and seniority in the same institute. Proper placement of the implant was guided by C-arm image intensifier. The results were evaluated taking into consideration the preoperative variables which included age, sex, mode of injury and type of fracture and operative variables which included the type of anesthesia, the duration of the procedure, the amount of fluoroscopy, and the mean number of blood units transfused to the patients.
Follow-up was done every 2 months for 6 months. On each visit, clinical, radiological, and functional outcome of the patient was assessed using the Salvati and Wilson hip scoring system [Table 1].
|Table 1: Salvati and Wilson hip function scoring system (maximum score=40)|
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Clinical and radiological data were analyzed using the statistical software epi-info version 3.5.1 (STEPS) released in August 2008 using arithmetic means, standard deviations, and confidence interval. P values were evaluated (P < 0.05 was considered significant). Fisher test and t-test were used to compare the data of the two groups.
| Results|| |
Of the 30 cases which were divided into two groups of fifteen each no statistical difference was found between them in terms of age (range between 50 and 70 years), sex distribution (15 male and 16 female) and type of fracture (whether intertrochanteric or subtrochanteric). Mode of trauma was most commonly found to be fall (80%) or road traffic accident (20%).
Time interval from day of injury to day of surgery was also similar (about 6–8 days). One patient from the PFN group and two from the DHS group had a head injury for which computed tomography scan was done and was found to be normal, and the patient recovered without any complication.
One patient from the PFN group had carcinoma breast with no evidence of metastasis which was treated adequately by chemotherapy after surgery.
Intraoperative complications were mainly due to instrumentation in the PFN group, an ill-fitting jig was found in 2 cases which caused the problem in lag screw insertion. Whereas in the DHS group, 2 patients had iatrogenic fractures of the lateral cortex during surgery and difficulty of reduction was faced in 1 case.
Surgery time was significantly lower in the PFN group than the DHS group (mean 44.53 vs. 59.67 min) P < 0.05 [Figure 1]a. Fluoroscopy time was significantly more in the PFN group than the DHS group (mean 1.26 vs. 0.86 min) P < 0.05 [Figure 1]b. Postoperative complications were more common in the DHS group (30% showed complications) with 2 patients having a lag screw cut out, and one having varus hip deformity whereas 2 patients had wound infections. In the PFN group, only 1 patient had urinary tract infection (not related to the procedure) which was adequately treated [Figure 1]c.
|Figure 1: (a) Duration of surgery. (b) Duration of fluoroscopy. (c) Postoperative complications. (d) Time to full weight bearing. (e) Salvati and Wilson hip function scoring|
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There was no significant difference in time to union between the two groups (mean 16.71 vs. 17.27 weeks) P > 0.05. Full weight bearing was started when the patient felt comfortable and this was found to occur at a significantly earlier stage in PFN group than the DHS group (mean 12 vs. 14.71 weeks) P < 0.05 [Figure 1]d. Blood loss was also higher in DHS fixation as patients required more units (66.6% patients had transfusion with 26.7% requiring 2 units) of blood transfused postoperatively than PFN (40% required transfusion with none requiring more than 1 unit) P > 0.05. Functional results according to the Salvati and Wilson scores showed significantly better results in the PFN group than DHS group (mean 31.47 vs. 27.6) P < 0.05 [Figure 1]e.
| Discussion|| |
In this study of 30 cases of pertrochanteric fractures of the femur, most patients were found to be elderly which is understandable as bones became osteoporotic with increasing age and patients tend to have pertrochanteric fractures even on trivial trauma like a domestic fall. Studies suggest these fractures are more common in females due to postmenopausal changes as found out by David  but in our study we found an equal number of male and female patients probably because males might have had an increased incidence due to more outdoor activities in our rural set up.
The most common mode of trauma falls in the older age group and road traffic accidents in younger patients.
In the study, we found that the surgery time was considerably lower in the PFN group primarily because it is a relatively closed procedure, and less dissection is required as compared to DHS fixation. In a study by Klinger et al. similar results were obtained with mean surgical time of 43 versus 61 min in PFN and DHS group, respectively.
Probably due to more soft tissue dissection, 13.3% of cases presented with wound infection in DHS group, compared to none in the PFN group. This may be attributed to low immune status of the patients as most of them were of asthenic build and belonged to low socioeconomic status. However, the closed nature of the procedure in PFN caused a significantly increased fluoroscopic exposure during surgery. Xu et al. reported similar results in their comparative study, that is, exposure time more in the PFN group. The amount of exposure, however, significantly reduced as the surgeon gains experience in the procedure.
Two patients with DHS implant had lag screw cut through leading to implant failure. This was associated with varus collapse of the neck-shaft angle and nonunion at the fracture site. Baumagaertner and Chrostowski (1992) reported the incidence of fixation failure to be as high as 20% in unstable fracture patterns. Osteoporosis was found to be the most important predisposing factor for this complication. One case with a screw cutout underwent revision surgery with bipolar femoral prosthesis [Figure 2], [Figure 3], [Figure 4].
|Figure 2: Unstable intertrochanteric fracture of a 65-year-old female patient suffering from a domestic fall involving the right hip joint|
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|Figure 3: A 4-month postoperative X-ray of the same patient fixation done by a dynamic hip screw having a lag screw cutout after bearing weight|
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|Figure 4: Hemiarthroplasty done on the same patient after implant failure|
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No significant difference was found between union time of the two groups, but the PFN group united slightly earlier (mean 16.24 weeks) [Figure 5] and [Figure 6] than the DHS group (mean 17.54 weeks). This might be because patients in the PFN group were able to commence mobilization earlier which improved microcirculation at the fracture site.
|Figure 5: Unstable intertrochanteric fracture of a 63-year-old female suffering from a domestic fall involving the right hip joint|
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|Figure 6: A 6 months postoperative X-ray of the same patient with proximal femoral nail in situ and union occurring|
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Range of stay of the patient in our hospital was 2–3 weeks. In the postoperative period, depending on the pain and tolerance of the patient, they were made to stand with support on the 4th or 5th postoperative day. They were gradually mobilized over the next 2–3 days until they could do the nonweight bearing ambulation with a walking frame.
The patients with PFN had earlier full weight bearing (without support) than DHS patients which was commenced according to general condition of the patient and his tolerability as well as the assessment of the intraoperative stability of the implant. The result concurred with studies by Klinger et al. and Xu YZ et al. who also advocated immediate weight bearing on the 1st postoperative day. This was not possible in our series because none of the patients had stable fracture patterns. Earlier weight bearing was possible in the PFN group mainly due to it being an intramedullary device which acts as a load sharing rather than a load-bearing device and counteracts the varus force of hip adductors by abutting to the lateral cortex of femur. Moreover, there was also lesser soft tissue dissection during operative period which led to earlier healing.
As the surgical wound in fractures treated by PFN is smaller, the mean blood loss was relatively small compared to those treated by DHS. On average, less postoperative transfusion was required in patients operated with PFN (mean 0.4) rather than DHS (mean. 8). Taeger et al. showed a 43% increased blood loss in a reduction of complex unstable fractures compared to stable ones.
The functional hip score was significantly better in the PFN group (mean 31.47) than with the DHS group (mean 27.6). The better PFN scores could be attributed to lesser postoperative pain in the patients due to lesser soft tissue dissection and early resumption of mobilization. The poor result in DHS group could also be attributed to other associated factors namely a long interval between trauma and surgery, development of postoperative infection and instability of the fixation leading to cutouts.
| Conclusion|| |
For the management of unstable pertrochanteric femoral fractures, PFN produces better results than DHS in terms of shorter surgery time, earlier weight bearing, lower infection rates, and less blood loss [Table 2].
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]