1 Introduction

Subtrochanteric fractures, which constitute 25% of proximal femur fractures, demonstrate bimodal distribution. They often appear as complicated fractures as a result of high-energy trauma in young male adults or as spiral fractures in the elderly and female patients. If compression, tensile, and torsional stresses are combined with decreased vascularity of the subtrochanteric region, malunion and nonunion can create difficulties for orthopedic surgeons.¹ Moreover, deterioration of lateral wall continuity seems to be an important factor of developing varus and abduction deformity. Both extramedullary and intramedullary fixation techniques have been used to manage subtrochanteric fractures.

Extramedullary fixation techniques have been used for more than 50 years. Extensive surgical dissection, and periosteal and soft tissue damage have led to the development of significant problems during the postoperative period.² However, in subtrochanteric fractures, it was predicted that the plate can provide a better control as it provides direct control of the lateral wall against stress loads.³

The development of intramedullary devices allow for reduction of complex fractures using less invasive methods. Although intramedullary devices allow for fixation with less blood loss using minimally invasive techniques, studies are underway to develop additional fixation methods. The difficulties experienced during anatomical reduction and the rate of complications encountered do not indicate guaranteed superiority over extramedullary fixation methods.⁴

In this study, we aimed to demonstrate the radiological and clinical outcomes of plate fixation and proximal femoral nails on varus deformity in the management of subtrochanteric femur region fractures.

2 Methods

We retrospectively analyzed 58 patients (34 males, 24 females; 33 right, 25 left; mean age, 65.1 ± 10.2 years) who underwent two different surgical techniques; extramedullary fixation technique with plate in 27 patients (group-1) and intramedullary fixation technique with PFN (proximal femoral nail) in 31 patients(group-2) for subtrochanteric femur fractures between 2011 and 2016.

The femoral neck shaft angles (NSA) of the non-injured sides were compared between the groups and the femoral neck shaft angles of the injured sides were compared between postoperative early period and the last follow up.

Inclusion criteria were the presence of a Subtrochanteric femoral fracture (Seinsheimer classification system I–V). Patients who underwent revision surgery after nonunion were excluded. Pathologic (Bi-phosponate-metastatic and primarily bone tumor), pediatric and open fractures were all excluded and osteoarthritis patients were also excluded from the study.

The fractures were classified based on the Seinsheimer classification system (Table 1). The American Society of Anesthesiologists (ASA) score of the patients was recorded during the preoperative period.

The operations were performed on a traction table under spinal anesthesia or general anesthesia with the guidance of fluoroscopy.

2.1

2.1 Surgical technique

The choice of fixation technique was based on surgeons preference. All the operations were carried out under control of C-armed fluoroscopy by using traction table. PFN was applied under fluoroscopy control by using guide wire after appropriate reduction was provided on the traction table to patients who had PFN preference. The plate (PF-LCP) was applied to the patients who underwent fluoroscopy control with minimally invasive technique after appropriate reduction on the traction table, a 6–8 cm incision was made to the patients whose fractures had not been adequately reduced and reduction was achieved with blunt dissection using reduction forceps without causing detachment of the periosteum. Osteosynthesis plates (PF-LCP 4.5/5.0; DePuy Synthes, Raynham, MA, USA) were used as extramedullary fixation material in 27 patients (Group 1) and A-PFNs (A-PFN® Antirotator Proximal Femoral Nail by TST Medical Devices) (Group 2) were used in 31 cases. Drains were not used for any patient.

Postoperatively, antibiotic prophylaxis was continued for 24 h after surgery. The same follow-up protocol was followed for both groups. The patients were mobilized and allowed to tolerated partial weight bearing on the postoperative first day with exercises of the active hip, knee and ankle.

Blood loss was calculated by summing the amount of blood before washing in the aspirator and after weighing the buffers used at the end of surgery. The quantity of erythrocyte (ERT) suspension transfused were evaluated. All of the patients received low-molecular-weight heparin for 20 days.

Measurements were performed with the radiologist with the help of computer-mediated measurement software. The patients also underwent radiography examination on the post-operative first day and varus and valgus angulation (Fig. 1) were evaluated in comparison with the uninjured contralateral hip. Union of the fractures and angulation between the hips were assessed with control radiograms at follow-up visits and last follow-up.

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Fig. 1 Demonstration of neck-shaft angle, using A-PFN. Last follow-up, Demonstration of neck-shaft angle, using PF-LCP. Last follow-up.

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Harris hip scores were recorded for patients of both groups in the last follow-up. Radiographic healing was defined as callus bridging of three of four cortices on anteroposterior and lateral radiographs as well as painless weight bearing on the affected extremity. Radiological assessments were made in a comparative manner with the contralateral side.

3 Results

There were 34 male and 24 female patients. The mean age was 65.1 ± 10.2 years. In 33 patients the right hip was operated on and in 25 patients the left hip was operated on. There was no significant difference between two groups in terms of the distribution of fracture types according to the Seinsheimer classification (p = 0.078).

No statistically significant difference was observed in the demographic characteristics of the patients (Table 2). The patients were operated on an average of 3.61 ± 1.34 days after admission. The mean follow-up period was 23.3 ± 12.6 and 21.7 ± 10.5 months in Groups 1 and 2, respectively. The preop ASA score of the patients was 2.59 in group 1 and 2.29 in group 2, without a significant difference between groups (p = 0.189).

The mean volume of blood loss in Group 1 was 203.8 ± 151.1 mL, and it was 127.1 ± 107.9 mL in Group 2. Blood loss difference was statistically significant between the groups (p = 0.029). While 1 unit of RBC suspension replacement was required in 4 patients in Group 1, 1 unit of RBC suspension replacement was required in 1 patient in Group 2.

The femoral NSA of non-injured side was measured 133.22 ± 1.94 in group 1 and 133.45 ± 2.21 in group 2 (p = 0,50). In group 1, early post operative injured sides of femoral neck angle was measured 131,37 ± 1,95 and last follow-up angle was 127,33 ± 2,40. In group 1, statistically significant decrease of NSA was observed to between early and last follow-up control radiographs (p = 0,025). In group 2, early post operative injured sides of NSA was measured 132,58 ± 1,97 and last follow-up angle was 131,71 ± 1,67. In group 2, there was no statistically significant difference of NSA in early and last follow-up control radiographs. (p = 0,96) (Table 3).

The mean Harris hip score at last visit was 67.59 ± 17.74 in Group 1, and 63.29 ± 13.8 in Group 2. There was no statistically significant difference between the groups in terms of functional hip score (p = 0,406).

Loosening of fixation material was observed in two patients in both groups. These patients underwent revision surgery and were not included in the study. A superficial wound site infection was detected in 2 patients in Group 1. One of these patients underwent lavage and debridement, while the other patient received antibiotic therapy and was monitored closely. No new infections and complications were observed during the follow-up period.

An abduction deformity of lateral wall was observed on the proximal femur fracture line in 3 patients in Group 2. These patients were followed up closely and fractures were healed at 6-month follow-up and included the study.

4 Discussion

Subtrochanteric fractures present difficulties in terms of reduction of the fracture and potential complications. This region is exposed to strong compression forces exerted from medial and tensile forces from a lateral direction, which can lead to implant failure. The medial cortex of the proximal femur can resist a compressive force of 84 kg/cm², while the lateral cortex can tolerate a tensile strength of 63 kg/cm². Biomechanical studies have demonstrated that the femoral cortex in the posteromedial subtrochanteric region is exposed to extreme stress. The lateral trochanteric wall is believed to be an important factor in the stabilization of proximal femoral fractures. These tensile forces in the lateral cortex are one of the most important factors that can complicate reduction procedures.^3,5 In the present study, we observed lateral wall abduction as a complication in PFNA fixation, which allows only limited lateral stabilization of the lateral cortex. Although plate fixation seems to be a better choice on lateral wall continuity and abduction control, we observed that PFNA provide a better control at varus angulation. We presume that applying an over-correction through the valgus direction while fixing may be helpful to prevent increase in varus angulation after plate fixation, and further study is needed on this aspect.

In biomechanical study performed on cadavers fracture models with subtrochanteric femoral gap by Forward et al.,⁶ the authors reported that the resistance to varus angulation PFN was superior to the PF-LCP. In our study, we have also clinically proven the superiority of A-PFN in preventing varus angulation. In another biomechanical study on cadavers, Wang et al.⁷ reported that subtrochanteric fractures type had become more complex, PFNA provides a more stable fixation than the plate. In terms of varus stabilization continuity, PFNA is a better option.

The main problem using intramedullary nails in the management of these fractures is revealed in cases with a shorter proximal fragment with a flexion, abduction, and external rotation deformity. This may result in an increase in nonunion rate (7%). Lateralization of the nail's entry point in subtrochanteric femoral fractures may result in varus angulation.⁸ Some authors recommend cerclage for adequate reduction of the fracture.⁹ However, there are still unanswered questions about potential bone devascularization, periosteal injury and infection caused by cerclage. Cerclage was not performed in the patient group that underwent intramedullary fixation in our study. Although we observed abduction deformity in 3 patients, we achieved fracture healing. As a result, we believe that delayed healing with deformity will cause less clinical problems.

Subtrochanteric fractures may cause more blood loss than femoral neck or intertrochanteric femur fractures. Compared with femoral neck fractures, patients with intertrochanteric fractures and subtrochanteric fractures required blood transfusions 2.37 and 4.03 times more frequently.¹⁰ In studies conducted, a longer incision, more blood loss, prolonged operative time, and a longer hospitalization period were detected for extramedullary fixation procedures.¹¹ Consistent with the literature, we found a statistically significant greater volume of blood loss in the extramedullary fixation group, though only 1 unit of RBC suspension replacement was needed in both the extramedullary and the intramedullary fixation groups.

In a review of 52 trials performed with 291.413 hip fracture patients, surgical treatment performed within the first 48 h was shown to reduce complications and mortality. Early fixation of femoral subtrochanteric fractures within the first 48 h after trauma is preferred whenever possible.¹² In our study, the patients were operated on an average of 3.61 days after admission due to a prolongation of the pre-anesthesia preparatory phase as a result of additional medical problems. Contrary to accounts in the literature, we did not observe mortality in cases operated on 3 days after the traumatic incident. However, the fact that we didn't evaluate whether a significant difference existed in terms of complications between the patients who were operated earlier and later is one of the limitations of our study.

In a meta-analysis evaluating intramedullary and extramedullary fixation methods for the management of subtrochanteric fractures, no significant difference was demonstrated between these 2 methods in terms of intraoperative data, postoperative complications, wound site infection, duration of hospital stay, or final outcome measures.¹³ In another meta-analysis of more than 3500 patients, no significant difference was found between the 2 fixation methods in an evaluation of postoperative complications, wound site infection rates, length of hospital stay, and follow-up outcome measures.¹⁴ In our study, contrary to literature findings, at the postoperative sixth month, comparisons between the final measurements of postoperative femoral neck-diaphysis angles of the affected and intact sides revealed greater postoperative varus angulation in the extramedullary fixation group. There was no significant difference between these 2 fixation methods in the postoperative sixth month Harris hip scores. Although femoral neck angulation caused serious problems in biomechanical load distribution, we could not observe this clearly reflected in the clinic outcome. However, we believe that it would be better to support it with larger series and prospective studies. In this context, we can describe our study as a guiding clinical study.

5 Conclusions

In intramedullary fixation subtrochanteric fractures, the protective effect on varus angulation is superior to the extramedular fixation method. However, we did not observe the superiority of both methods clinically over each other and we believe that both methods are good alternatives for each other.

Funding

We declare that there is no funding source.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This article does not contain any studies with human participants or animals performed by any of the authors.