A Meta-analysis Comparing Lateral Decubitus with Supine Position for Surgery for Intertrochanteric Fractures

Purpose: There are few studies compares surgery with proximal femoral nail antirotation (PFNA) in lateral decubitus with that in supine position about their advantages and disadvantages for patients with intertrochanteric femoral fractures. Previous studies reported conflicting findings. This meta-analysis was to compare the efficacy and safety of surgery with PFNA in different surgical positions. Methods: Relevant randomized controlled trials comparing surgery with PFNA in lateral decubitus with surgery in supine position for intertrochanteric fractures patients were included into this meta-analysis. Inclusion criteria of this meta-analysis were: randomized controlled trials comparing lateral decubitus with supine position for surgery for intertrochanteric fractures and reporting at least one of the main outcomes, including blood loss, operating time, hospital stay, and length of incision, Harris values and union time. Results: Six randomized controlled trials were finally included into this meta-analysis. Pooled results showed that there were less blood loss, less operation time, smaller incision and higher Harris values score in lateral decubitus group. Sensitivity analysis by sequential omission of individual studies showed the significance of weighted mean difference was robust, which suggested this outcome was credible. Conclusions: Surgery with PFNA in lateral decubitus can benefit intertrochanteric fractures patients with less blood loss, less operation time, shorter incision and high Harris values scores compared with surgery in supine position according to our research. Citation: Liu F, Xie H, Liang W, Ye D, Yao Y (2016) A Meta-analysis Comparing Lateral Decubitus with Supine Position for Surgery for Intertrochanteric Fractures. J Arthritis 5: 211. doi: 10.4172/2167-7921.1000211


Introduction
Intertrochanteric femoral fracture has become increasingly common especially in elderly patients [1,2]. Treatment of intertrochanteric femoral fracture depends on medical condition, bone quality and biomechanics of the fracture configuration of the patient [2,3]. In the past few decades, Intertrochanteric Femoral Fractures could be treated by using several effective internal fixation such as dynamic hip screw (DHS), dynamic condylar screws (DCS), proximal femoral nail (PFN) and proximal femoral nail antirotation (PFNA). Among these internal fixations, proximal femoral nail antirotation shows its advantages compared with other internal fixations [4][5][6]. Surgery with PFNA can benefit patients with intertrochanteric femoral fracture with less blood loss, less operation time, fewer complications. In result, PFNA is used globally.
Proximal femoral nail antirotation is generally used in surgery with supine position. This surgery has a high require of operating bed and equipment of fluoroscopy, which limits it being used in more primary hospitals. Recently, more and more surgeons perform surgery with PFNA in lateral decubitus. Surgery with PFNA in lateral decubitus doesn't need an extension table, so it can be performed in primary hospitals. Additionally, some surgeons observe that surgery in lateral decubitus has some advantages, such as less blood less, less operation time, comparing with surgery in supine position. However, there are not so many studies compares surgery in lateral decubitus with that in supine position about their advantages and disadvantages. Thus, to provide the most comprehensive assessment of the lateral decubitus and supine position for surgery for intertrochanteric fractures, we performed this metaanalysis based on all relevant randomized controlled trials comparing lateral decubitus with supine position for surgery for intertrochanteric fractures.

Search strategy and eligibility criteria
We searched Pubmed, Embase, and China Knowledge Infrastructure (CNKI) databases for randomized controlled trials comparing lateral decubitus with supine position for surgery for intertrochanteric fractures. We used the following search iterms: ("PFNA" or "proximal femoral nail antirotation") and (("surgical position") or (("lateral decubitus") and ("supine position"))) and ("intertrochanteric fractures" or "peritrochanteric fractures" or "subtrochanteric fractures" or "pertrochanteric fractures" or "extracapsular hip fractures"). The references of the retrieved articles were also confirmed and language restriction wasn't imposed in our search.
Inclusion criteria of this meta-analysis were: randomized controlled trials comparing lateral decubitus with supine position for surgery for intertrochanteric fractures and reporting at least one of the main outcomes, including blood loss, operating time, hospital stay, and length of incision, Harris values and union time. Exclusion criteria were: cases series that investigated either lateral decubitus or supine position for surgery for intertrochanteric fractures, data were duplicated, demographic background of the patients and preoperative conditions were not similar, usable data were not reported and inconsistencies were resolved by reaching a consensus between all authors after discussion.

Data extraction and quality assessment
We extracted following information from every study: Year of publication, study design, number of patients, fracture classification, average follow-up time, blood loss, operating time, hospital stay, length of incision, Harris values and union time. Quality of randomized controlled trials included in this meta-analysis was assessed by the Jadad score [7], which was as follows: was the study described as randomized, was the study described as double blind, was there a description of withdrawals and dropouts [7]. Randomized controlled trails with scores no less than three points were defined as high quality, while with scores less than three points were defined as lesser quality randomized controlled trails [7].

Statistical analysis
In each study the pooled odds ratio (OR) with a 95% confidence interval (CI) was calculated for dichotomous outcomes, and weighted mean difference (WMD) with a 95% confidence interval (CI) was calculated for continuous outcomes. To assess the betweenstudy heterogeneity more precisely, both the Chi 2 based Q statistic test (Cochran's Q statistic [8]) to test for heterogeneity and the I 2 statistic to quantify the proportion of the total variation attributable to heterogeneity were calculated [9]. A significance level of less than 0.10 for the Chi 2 test was interpreted as evidence of heterogeneity. When there was no statistical evidence of heterogeneity, a fixed effect model was adopted [10]; otherwise, a random effect model was chosen [11]. Besides, to validate the credibility of outcomes in this metaanalysis, a sensitivity analysis was performed by sequential omission of individual studies [12]. Publication bias was investigated by funnel plot and an asymmetric plot suggested possible publication bias [13]. Statistical analyses were performed with the software program RevMan (Version 5.0, Copenhagen: The Nordic Cochrane Centre, the Cochrane Collaboration). All P-values were two-sided and a P-value of less than 0.05 was deemed statistically significant.

Study characteristics
There were 67 initial record identified. A total of 57 of these records were excluded, leaving 10 potentially relevant studies. Then we excluded 2 non-random studies and 2 studies for no available data. Six randomized controlled trials were included into this meta-analysis [14][15][16][17][18][19]. Table 1 summarized the main characteristics of the included studies. Table 2 showed the methodological quality of included studies in this meta-analysis. The quality of randomized controlled trials included was assessed using the Jadad scoring system, and three trials were high quality randomized controlled trials with scores no less than three points ( Figure 1).

Blood loss and operation time
Data for blood loss were reported in 6 trials (Table 3 and Figure  2). There was significant heterogeneity among these trials (I 2 =95%, P<0.00001). The random effects model was used to pool the results. It was showed in this meta-analysis that surgery in lateral decubitus was marginally associated with less blood loss compared with surgery in supine position (WMD Blood loss =-52.12 ml, 95%CI -87.61 to -16.63, P=0.004) ( Figure 2). Besides, sensitivity analysis by sequential omission of individual studies showed the significance of WMD Blood loss was robust, which suggested this outcome was credible.
Data for operation time were reported in 5 trials (Table 3 and Figure 2). There was no significant heterogeneity among these trials (I 2 =0%, P=0.66). The fixed effects model was used to pool the results. It was showed in this meta-analysis that surgery in lateral decubitus was marginally associated with less operation time compared with surgery in supine position (WMD Operation time = -14.77 min, 95%CI -16.55 to -12.99, P<0.00001) ( Figure 2). Besides, sensitivity analysis by sequential omission of individual studies showed the significance of WMD Operation time was robust, which suggested this outcome was credible.

Length of incision
Data for length of incision were reported in 3 trials (Table 3 and Figure 3). There was no significant heterogeneity among these trials (I 2 =24%, P=0.27). The fixed effects model was used to pool the results.   It was showed in this meta-analysis that surgery in lateral decubitus was marginally associated with smaller incision compared with surgery in supine position (WMD Length of incision =-2.47 cm, 95%CI -2.64 to -2.30, P<0.00001) (Figure 3). Besides, sensitivity analysis by sequential omission of individual studies showed the significance of WMD Length of incision was robust, which suggested this outcome was credible.

Harris values
Data for Harris values were reported in 3 trials (Table 3 and Figure 4). There was no significant heterogeneity among these trials (I 2 =0%, P=0.83). The fixed effects model was used to pool the results. It was showed in this meta-analysis that surgery in lateral decubitus was marginally associated with higher score compared with surgery      (Figure 4). Besides, sensitivity analysis by sequential omission of individual studies showed the significance of WMD Harris values was robust, which suggested this outcome was credible.

Hospital stay and union time
Data for hospital stay were reported in 3 trials (Table 3 and Figure  5). There was significant heterogeneity among these trials (I 2 =79%, P=0.009). The random effects model was used to pool the results. Metaanalysis showed that there was no different in term of the hospital stay between these two groups (WMD Hospital stay =-0.89 days, 95%CI -2.34 to -0.55, P=0.23) ( Figure 5). Besides, sensitivity analysis by sequential omission of individual studies showed the significance of WMD Hospital stay was robust, which suggested this outcome was credible.
Data for union time were reported in 4 trials (Table 3 and Figure  5). There was significant heterogeneity among these trials (I 2 =94%, P<0.00001). The random effects model was used to pool the results. Meta-analysis showed that there was no different in term of the union time between these two groups (WMD Union time =-1.00 weeks, 95%CI -3.20 to -1.19, P=0.37) ( Figure 5). Besides, sensitivity analysis by sequential omission of individual studies showed the significance of WMD Union time was robust, which suggested this outcome was credible.

Discussion
Proximal femoral nail antirotation is widely used in surgery for intertrochanteric fractures [2,3]. Surgeons can finish the surgery with PFNA either in lateral decubitus or in supine position. There are some studies comparing the outcomes of lateral dicubitus and supine      position for surgery for intertrochanteric fractures, but there is obvious inconsistency of effects of those studies [14][15][16][17][18][19][20][21]. The better surgical position of surgery with PFNA remains controversial. Therefore, we performed this meta-analysis by including 6 randomized controlled trials to provide the most comprehensive assessment of lateral decubitus or supine position for surgery for intertrochanteric fractures. This metaanalysis showed the result that there were less blood loss (WMD Blood loss =-52. 12  The PFNA, which have been widely adopted for patients with intertrochanteric fractures, is an intramedullary device with a helical blade rather than a screw for better purchase in the femoral head [4][5][6]22,23]. Surgery with PFNA in supine position has a high require of operating bed and equipment of fluoroscopy, which limits it being used in more primary hospitals. On the contrary, Surgery with PFNA in lateral decubitus doesn't need an extension table, so it can be performed in primary hospitals [18,19]. According to our meta-analysis, surgery with PFNA in lateral decubitus can benefit intertrochanteric fractures patients with less blood loss, less operation time, shorter incision and high Harris values scores. Thus, we should improve surgical technique with PFNA in lateral decubitus and generalize it to primary hospitals so that it can benefit more and more patients with intertrochanteric fractures.
Significant heterogeneity was observed between the included trials for intraoperative blood loss, hospital stay and union time. This heterogeneity may be attributable to variation in the skills of the surgeons and the different types of intertrochanteric fractures. The eligibility criteria for inclusion of intertrochanteric fractures patients were different from each other. The difference may have an influence on the obvious consistency of effects across those included studies and result in the heterogeneity. Besides, samples in trials included in this meta-analysis are not quite large, which may influence the heterogeneity. An individual patient data meta-analysis is necessary to ensure uniformity in either defining patients' characteristics for intertrochanteric fractures or defining outcome measures [24,25]. More randomized controlled trials with large samples are needed to decrease heterogeneity and make the outcome more meaningful.
In conclusion, surgery with PFNA in lateral decubitus can benefit intertrochanteric fractures patients with less blood loss, less operation time, shorter incision and high Harris values scores compared with surgery in supine position. In term of hospital stay and union time, there is no difference in these two surgical positions. However, more powered randomized studies are needed to identify the outcomes from this meta-analysis. Long-term period effects also need further studies.