Management of subtrochanteric femur fractures: is open reduction associated with poor outcomes?

Subtrochanteric fractures are defined as those encountered between the inferior border of lesser trochanter and 5 cm distal to it [1]. They generally account for 5–34% of all proximal femoral fractures [2‐4], and the ‘gold standard’ of their treatment is intramedullary (IM) nailing. Their management can be very challenging because of their unique biomechanical and anatomical features (moderate vascularity and high concentration of biomechanical stresses) [5‐9]. Furthermore, the multiple deforming forces acting on the fracture fragments make their reduction difficult. Consequently, it is not surprising that a 4.7% reoperation rate has been reported related to fracture non-union and metalwork failure [3, 10].

When closed reduction fails to improve fracture alignment, open reduction has been recommended [11‐13]. However, open reduction has been associated with such complications as infection, non-union, prolonged surgical time and blood loss requiring blood transfusion [11‐13]. Interestingly, published evidence remains conflicting, with some studies reporting an increased incidence of non-union and infection [14, 15], whilst other studies report no difference with regard to non-union, infection, transfusion rates and fracture vascularity [12, 13]. Overall, there appears to be lack of strong evidence comparing the outcomes of open versus closed reduction in the management of subtrochanteric femoral fractures treated with cephalomedullary nailing.

Therefore, the aim of our study was to report on the factors associated with the need for open reduction and to investigate whether open reduction is associated with a higher risk for complications. Moreover, to assess if cerclage wiring has an impact on the development of fracture non-union. Our hypothesis was that open reduction is associated with an increased risk of infection and non-union, whilst the use of cerclage wires further increases this risk.

Following institutional board approval (LTH#2591), we conducted a retrospective analysis of all consecutive eligible patients presenting in a Level I Trauma Centre over a period of eight years (2009–2016). We included all skeletally mature patients presenting with a fracture extending through the subtrochanteric region that was subsequently treated with an IM nail. Exclusion criteria included the following: pathological fractures (secondary to malignancy or atypical fractures), patients receiving prophylactic nailing for tumours (without a fracture) or incomplete fractures and patients who had their primary operation in other institutions.

Information collected included demographics and comorbidities, operation details, complications and outcomes. Fractures were classified according to the Russell Taylor classification system [16, 17]. Radiographic features were also analysed, with all radiographic measurements being performed independently by MP and JV, with any disagreements resolved by the senior author (PVG).

All patients were managed by the multidisciplinary team, under a set protocol. All patients were positioned supine on a traction table, with post in the perineal area and with the contralateral leg held into lithotomy position. Closed reduction was first attempted and if unsuccessful, open reduction was performed. The use of clamp assisted reduction and cerclage wires was left to the discretion of the operating surgeon. Post-operatively, patients followed a strict physiotherapy regime aiming for early mobilisation and were closely monitored for complications. Superficial infection was defined as erythema, pain, swelling, discharge and delayed wound healing, along with raised inflammatory markers in the early post-operative period [18]. Deep infection was defined as infection involving the fascial, muscular layers and beyond, surrounding the metalwork and necessitating further surgical interventions [19]. Superficial infections were generally treated with oral antibiotics, as compared to deep infections that were treated with a combination of intravenous (IV) antibiotics, wound debridement and removal/revision of implants, as deemed appropriate.

Subtrochanteric fractures have been previously associated with a high risk of complications, some of which could be potentially preventable [22‐24]. In the literature, there is still a lack of evidence comparing the outcomes of open versus closed reduction [22, 25‐28]. Most of these studies are small in sample size [22, 25, 27], whilst some assess the elderly age group only [27], but no study reports on the associations of open reduction. Our study, therefore, represents the first study reporting on the associations of open reduction in subtrochanteric femur fractures and related complications.

Open reduction has traditionally been met with some reluctance. This is due to the misbelief that open reduction may compromise the local fracture biology and vascularity [5], thereby reducing the threshold of what could be deemed as an ‘acceptable’ suboptimal reduction. Similarly, cerclage wiring was believed to cause strangulation of the bone, risking necrosis and ultimately failure of healing [29]. Recent studies have, however,, challenged this school of thought. Histological and anatomical studies by Nather et al. [30] and Pazzaglia et al. [31] have both described the periosteal blood supply as circumferential. Lenz et al.’s ex-vivo study using human diaphyseal bone further confirmed this, whereby they found no periosteal compression when using a cerclage wire or a cable [32, 33]. Additionally, in a systematic review by Förch et al. on the effect on cerclage wiring to periosteal perfusion, the group reported no significant evidence to support this [34]. Furthermore, biomechanical studies have also demonstrated how the use of cerclage wire is advantageous, as it stabilises the medial hinge and raises the threshold of cyclical compressive loading tolerated by the femur before reaching plastic deformation [35]—factors found to significantly decrease the rate of implant failure following IM nailing [35].

Contrary to the bimodal age and gender distribution [2], and unimodal older male and female distribution reported in the literature [36‐38], we identified a bimodal male, unimodal older female age distribution in our cohort. The majority of subtrochanteric fractures (82.4%) in our adult population had comminution or distal diaphyseal extension—all characteristics of an unstable fracture pattern. This, therefore, explains the high rate of open reduction demonstrated in our study population (48%), which is in keeping with that reported by other studies (range: 33.3–82.2%) [25‐27]. To reduce the bias of our outcomes, we matched the two groups as per age, gender and mechanism of injury. Only distal fracture extension to the diaphysis was found to be different (p < 0.001), whilst the rest of the fracture characteristics were comparable in the two groups. Furthermore, our regression analysis confirmed that open reduction was associated with a longer surgical time (OR: 3.09), which suggests a more challenging fracture reduction mandating open reduction in the first place.

Kilinc et al. reported a 5.8% superficial and 3.9% of deep infection in their study on 52 patients with cerclage wiring of subtrochanteric fractures treated with IM nailing [39]. Studies comparing open and closed reduction of subtrochanteric fractures treated with cephalomedullary nailing reported similar infection rates between the two groups, which range between 0 and 1.7% [25‐28, 40]. These studies, however, are limited by their small sample size and restricted age groups. Having overcome the aforementioned limitations, our study has conclusively revealed that there is a statistically significant higher risk of developing superficial wound infection in the open reduction group (OR: 7.88). Contrary to common belief, deep infection was not statistically increased amongst the open reduction group.

There is a paucity of studies in the literature which compared the blood transfusion requirement between subtrochanteric fractures requiring open versus closed reduction. Codesido et al. reported no difference in transfusion requirements between the two groups [26], whereas Shukla et al. reported higher transfusion requirement in the open reduction group [27]. We found that open reduction poses a higher risk of requiring blood transfusion within the initial 48-h postoperative period (OR: 2.44). The higher transfusion risk could be explained by our findings wherein open reduction was performed in fractures requiring a prolonged surgical time, more extensive surgical dissection and, therefore, soft tissue damage—all contributory factors towards a higher bleeding risk.

With regard to the non-union rates, these have been reported to be lower in open reduction group [25, 26]. Karayiannis et al. reported rates of symptomatic non-union to be 5.8% and 6.3% in the open reduction and closed reduction group, respectively [25]. Codesido reported no non-unions amongst subtrochanteric fractures requiring open reduction, whilst 8.3% of the closed reduction group developed non-union [26]. Kilinc et al. (cerclage wire reduction) and Mingo-Robinet et al. (clamp assisted reduction only) both reported no non-unions in their cohorts of patients [28, 39]. Out of the three main operative factors, Krappinger et al. found that the lack of medial cortical support and varus malalignment as significant risk factors for non-union in subtrochanteric fractures treated by IM nailing [3]. Even though our study has demonstrated no difference in the non-union rates between subtrochanteric fractures treated with closed or open reduction, we did identify that open anatomical reduction achieved by cerclage wire/cable to have a lower non-union rate (OR: 0.20), when compared to ‘clamp assisted only’ open reduction. One could assume that higher non-union rates seen in open reduction group were secondary to suboptimal exposure and reduction. Interestingly, the use of cerclage wires/cables seems to reduce the risk of non-union. Possible mechanisms behind this could be a better reduction of the fracture with smaller fracture gaps and restoration of the medial buttress.

To our knowledge, our study is the largest cohort series reported in the literature to date comparing the outcomes of closed versus open reduction of subtrochanteric femur fractures treated with IM nailing. With no exclusion criteria posed upon age or comorbidity, our study provides a better overview of the overall fracture demographics and epidemiology of subtrochanteric femur fractures encountered in a Level 1 Trauma Centre serving a metropolitan population. By matching the two groups with respect to age, gender and mechanism of injury, we reduced bias that could result from baseline differences between the two populations. The retrospective nature of our study on the other hand meant certain data may be subjected to bias. Although redness, swelling and mild discharge in the first few post-operative days are signs of physiological inflammation of wound healing, this could easily be clinically over-diagnosed as ‘superficial wound infection’ by non-orthopaedic physicians, junior doctors, district nurses or advance nursing practitioners who are less experienced in assessing surgical wounds. Therefore, we may have overestimated this risk, with an inherent bias of superficial infection towards open reduction. We also accept that the assessment of fracture pattern is subject to intra- and inter-observer reliability. We did, however, attempt to overcome this weakness by having two independent assessors for the analysis of fracture pattern and radiological measurements. Of note, fractures requiring an open reduction are generally more difficult to reduce and, therefore, are subjected to a higher risk of complications including non-union, hence a potential bias against this group.