Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 2  |  Issue : 3  |  Page : 97-103

Efficacy and safety of cemented and cementless prostheses in the repair of unstable intertrochanteric fractures in the elderly: study protocol for a non-randomized controlled trial


1 Department of Orthopedics, Harrison International Peace Hospital, Hengshui, Hebei Province, China
2 Department of Physical Examination, Harrison International Peace Hospital, Hengshui, Hebei Province, China

Date of Web Publication31-Aug-2017

Correspondence Address:
Tie-miao Yu
Department of Orthopedics, Harrison International Peace Hospital, Hengshui, Hebei Province
China
Login to access the Email id

Source of Support: This study was supported by the Scientific and Technological Achievements of Hengshui City of China, No. 201440076-2., Conflict of Interest: None


DOI: 10.4103/2542-4157.213689

Rights and Permissions
  Abstract 

Background and Objectives: Patients with unstable intertrochanteric fractures are older, and body function gradually degrades with age. The reduction and fixation of these fractures are difficult. Total hip arthroplasty is one of the main surgical treatments for unstable intertrochanteric fractures in the elderly. This trial was designed to identify the differences between cemented and cementless prostheses in the repair of unstable intertrochanteric fractures in the elderly so as to provide a clinical basis for the selection of hip prostheses for treating unstable intertrochanteric fractures in elderly patients.
Design: A prospective, single-center, non-randomized, controlled, clinical trial.
Methods: Eighty-six elderly (> 65 years old) patients at the Harrison International Peace Hospital of China with unstable intertrochanteric fractures underwent total hip arthroplasty. Forty-four patients in the control group received a cemented SPII prosthesis (Link, Hamburg, Germany). Forty-two patients in the trial group received a cementless Wagner prosthesis (Zimmer, Spartanburg, SC, USA). All patients were followed for 6 months.
Outcome measures: The primary outcome was an excellent or good Harris hip score at 6 months postoperatively to evaluate the recovery of hip function. The secondary outcomes were the changes in Harris hip scores or morphological changes in the hip on X-ray preoperatively and 1, 3, and 6 months after surgery, intraoperative blood loss, operative time, postoperative blood transfusion volume, ambulation time, amount of drainage at the incision 1 month after surgery, and the incidence of adverse reactions at 6 months after surgery.
Results: Postoperative blood transfusion volume and the amount of drainage were higher in the trial group than in the control group (P < 0.05). The rate of excellent or good Harris hip scores was not significantly different between the trial and control groups (P > 0.05). Harris scores were lower in the trial group than in the control group at 1 and 3 months postoperatively (P < 0.05). The incidence of adverse reactions was not significantly different between the two groups at 6 months after surgery (P > 0.05), but bone cement poisoning was found in four patients in the control group.
Conclusion: Efficacy and safety of cemented and cementless prostheses for unstable intertrochanteric fractures in the elderly were good. However, the cemented prosthesis was associated with a risk of bone cement poisoning.
Trial registration: Clinical Trails.gov indentifier: NCT03193697.

Keywords: clinical trial; unstable intertrochanteric fractures; cemented prosthesis; cementless prosthesis; hip; elderly; Harris hip scores


How to cite this article:
Yu Tm, Miao Hl. Efficacy and safety of cemented and cementless prostheses in the repair of unstable intertrochanteric fractures in the elderly: study protocol for a non-randomized controlled trial. Clin Trials Orthop Disord 2017;2:97-103

How to cite this URL:
Yu Tm, Miao Hl. Efficacy and safety of cemented and cementless prostheses in the repair of unstable intertrochanteric fractures in the elderly: study protocol for a non-randomized controlled trial. Clin Trials Orthop Disord [serial online] 2017 [cited 2024 Mar 19];2:97-103. Available from: https://www.clinicalto.com/text.asp?2017/2/3/97/213689


  Introduction Top


Background

Intertrochanteric fractures are common types of hip fractures. [1],[2] With the growth of the global aging population, the number of elderly fracture patients with osteoporosis is increasing. Thus, the difficulty of treating intertrochanteric fractures had also increased. Unstable intertrochanteric fractures refer to fractures from the base of the femoral neck to the level of the lesser trochanter. [3],[4],[5],[6] Because the aging population in China is increasing gradually, the incidence of unstable intertrochanteric fractures is increasing year by year. [7],[8],[9] Clinically, more than 90% of intertrochanteric fractures occur in the elderly who are over 65 years of age, and the mortality rate for these patients is high. The reduction and fixation of these fractures are difficult. Therefore, it is of great significance to patients with unstable intertrochanteric fractures to find timely and effective treatments for their injuries.

Clinically, internal fixation and artificial joint replacement are the primary methods of treating unstable intertrochanteric fractures. The surgical approach for internal fixation is affected by the bone quality of the patients. If the patient has osteoporosis, it may lead to the failure of the first operation, affecting the overall prognosis of the patient. Therefore, this method of treatment is becoming less popular in clinical practice. [10],[11] The efficacy of joint replacement for the treatment of intertrochanteric fracture is remarkable. It can help the patient obtain immediate stability and reduce complications, so it is popular with patients and physicians alike. [12],[13],[14] The most commonly used artificial joint replacement types include cemented and cementless prostheses, [15] but the differences in their efficacy and safety remain poorly understood.

Significance

This trial explored the use of different hip replacement materials in elderly patients with unstable intertrochanteric fractures, and aimed to provide the experience and basis for hip arthroplasty in elderly osteoporosis patients with unstable intertrochanteric fractures.




  Methods/Design Top


Study design

This study was a prospective, single-center, non-randomized, controlled, clinical trial.

Study setting

This study was performed at the Harrison International Peace Hospital of Hebei Province of China.

Study procedures

Eighty-six patients with unstable intertrochanteric fractures underwent total hip arthroplasty at the Harrison International Peace Hospital. The patients were voluntarily divided into two groups. Forty-four patients in the control group received a cemented prosthesis. Forty-two patients in the trial group received a cementless prosthesis. All patients were followed for 6 months.

The rate of excellent or good Harris hip scores was observed at 6 months postoperatively. Morphological changes in the hip joint on X-ray and the incidence of adverse reactions were observed to comprehensively evaluate the efficacy and safety of two kinds of prostheses in the treatment of unstable intertrochanteric fractures in elderly patients.

[Figure 1] shows the flow chart describing the study protocol.
Figure 1: Flow chart of trial protocol.

Click here to view


Ethical requirements

The study protocol was approved by the Ethics Committee of Harrison International Peace Hospital of China, approval number 2013-37.

All protocols were performed in accordance with the Ethical Principles for Medical Research Involving Human Subjects in the Declaration of Helsinki.

The writing and editing of the article were performed in accordance with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) (Additional file 1 [Additional file 1]).

Written informed consent was provided by each patient and their family members after they indicated that they fully understood the treatment plan and study protocol.

Inclusion criteria

Patients presenting with all of the following criteria were considered for study inclusion:

  • Unstable intertrochanteric fractures identified by imaging and laboratory examination [16]
  • Age greater than 65 years old
  • Males or females
  • Willing to participate in the study and provide informed consent


Exclusion criteria

Patients with one or more of the following conditions were excluded from this study:

  • Contraindications to joint replacement, such as acute myocardial infarction or other serious medical comorbidity
  • Obvious obstacles in language communication


Baseline analysis

The demographic data and general disease history of the included patients are shown in [Table 1].
Table 1: Baseline data and general disease history of patients

Click here to view


Sample size

Based on our experience, we hypothesized that the rate of excellent or good Harris hip scores would be 85% and 70% in the trial group and control group, respectively, at 6 months postoperatively. Taking β = 0.2 and Power = 80% with a significance level of α = 0.05, the sample size of n = 93 was calculated using PASS 11.0 software (PASS, Keysville, UT, USA). Assuming a patient loss rate of 20%, we required 112 patients per group. After screening based on the inclusion and exclusion criteria, 86 patients were included in the study (n = 42 in the trial group; n = 44 in the control group).

Recruitment

Recruitment information was posted on the official website of Harrison International Peace Hospital. The patients or their families obtained contact information of a researcher from the hospital's official website, contacted the research leader directly by sending an e-mail or making a telephone call, and specified the time to personally visit Harrison International Peace Hospital. The researchers informed them of the details of the study protocol. After providing informed consent, the potential participants were screened using the inclusion and exclusion criteria.

Randomization and blinding

This was an open-label trial. Patients, physicians, and assessors were not blinded to group information or therapeutic regimen. Randomization was not used.

Total hip arthroplasty

After conventional anesthesia (epidural anesthesia was preferred), all patients were placed in the lateral position. After disinfection and placement of surgical drapes, the operation was conducted using a posterolateral approach.

The control group received a cemented prosthesis. The appropriate femoral stem prosthesis was selected according to the patient's specific situation. After reaming, the bone marrow cavity was flushed and bone cement was injected into the cavity. The femoral stem was then inserted. After the bone cement was completely cured, a suitable cemented SPII prosthesis (Link, Hamburg, Germany) was placed. The articular capsule was sutured and the incision was closed. The patients were reexamined at 1, 3, and 6 months after the operation.

The trial group received a cementless prosthesis. The skin and gluteus maximus were incised in order to ensure that the femoral stem implant could be placed in a good position in the medullary cavity, tightly pressed against the bone. According to the size of the femoral head, we selected and installed an appropriately sized double-acting femoral head model. The Wagner prosthesis (Zimmer, Spartanburg, SC, USA) was used in this trial. After closing the incision, a drainage tube connected to an autologous blood transfusion device was installed. The patients were reexamined at 1, 3, and 6 months after the operation.

Hip function evaluation: The patients were examined before the operation and 1, 3, and 6 months after the operation. In accordance with Harris hip scoring criteria, [17] hip function was assessed with regard to joint function, pain, and range of motion. The maximum possible score is 100, with 90-100 being excellent, 80-89 being good, 70-79 being average, and < 70 being poor.

Outcome measures

Primary outcome measure


The rate of excellent or good Harris hip scores at 6 months postoperatively was defined as the following: number of patients with excellent or good Harris hip scores/total number of patients × 100%. A high rate of excellent or good scores indicates good hip function.

Secondary outcome measures

Changes in Harris hip scores were recorded preoperatively and 1, 3, and 6 months postoperatively, with high Harris hip scores indicating good hip function.

Morphological changes in the hip on X-ray were observed preoperatively, and 1, 3, and 6 months after surgery, with the morphology of the hip being observed on anteroposterior and lateral images.

Heterotopic ossification was classified via the Brooker classification system. Grade 1: Ossification islands around the hip; Grade II: Bone projection of the pelvis or proximal femur at least 1 cm away from the opposite surface; Grade III: Bone projection of the pelvis or proximal femur reducing space less than 1 cm away from the opposite surface; Grade IV: Hip ankylosis. [18] The quality of bone cement was graded using Barrack's classification. [19] Grade A: Radiolucent zone is not found in the bone-cement interface, and the bone marrow cavity is completely filled with bone cement. Grade B: A few radiolucent zones are seen in the bone-cement interface.

Intraoperative blood loss was measured, with high blood loss indicating poor surgical quality.

Operative time was recorded, with a short operative time indicating an uneventful surgery.

Postoperative blood transfusion volume at 1 month after surgery was assessed, with a large blood transfusion volume indicating considerable blood loss.

Ambulation time at 1 month after surgery was measured, with a short ambulation time indicating fast recovery.

The amount of drainage 1 month after surgery was recorded, with a large amount of drainage indicating large blood loss.

The incidence of adverse events at 6 months after surgery was documented and presented using the following formula: number of patients with adverse events/total number of patients ×100%.

The schedule by which outcome measurements were taken is shown in [Table 2].
Table 2: Timing of outcome assessments

Click here to view


Adverse events

We recorded adverse events, including incisional pain, bone cement poisoning, pulmonary infection, mental disorders, and acute cerebral infarction.

If severe adverse events occurred, the investigators reported the details of the complications to the principle investigator and the institutional review board within 24 hours, including the dates of occurrence and measures taken to treat them.

Data collection, management, analysis, and open-access

The data collection and records of all cases reported in the trial were complete, clear, and true. The case reports were consistent with the patients' original data and the declared data. The collected data were inputted into a computer in the record room of Harrison International Peace Hospital.

Data were processed by a designated person, and aggregated once a month. During the clinical trial, hospital clinic visits were conducted periodically by the clinical ombudsman to ensure that all the contents of the protocols were strictly observed. Simultaneously, raw data were checked to ensure consistency with the case report forms.

Statistical analysis of the data was performed by professional statisticians. The statisticians wrote the research report and submitted it to the researcher for review.

Anonymized trial data will be open access and published at www.figshare.com.

Statistical analysis

Statistical analysis was performed using SPSS 19.0 software (IBM, Armonk, NY, USA) and followed the intention-to-treat principle.

Normally distributed measurement data were expressed as means ± standard deviation and minimums and maximums. Non-normally distributed measurement data were expressed as the lower quartile (q1), median, and upper quartiles (q3). Count data were expressed as percentages. Two-sample t-tests were performed for comparison of Harris hip scores, operative time, intraoperative blood loss, postoperative blood transfusion volume, ambulation time, and postoperative drainage volume in both groups. Repeated measures analysis of variance was conducted for intragroup comparison of Harris hip scores at various time points. Pearson's chi-square test was carried out for comparison of the rate of excellent or good Harris hip scores and the incidence of adverse reactions in both groups.

The significance level was set at α = 0.05.


  Results Top


Trial Status: Patients were recruited in January 2014. Data analysis will be completed in December 2017. Partial results are presented in the following sections.

Baseline data

Eighty-six patients, including 45 females and 41 males, had a mean age of 72.76 ± 5.31 years. The cause of injury was a fall in 67 cases, a traffic accident in 12 cases, and a pathological fracture in 7 cases. All patients had a similar burden of chronic disease. Fractures were classified using the Evans-Jensen classification [20] : 10 cases were grade IIA, 24 cases were grade IIB, and 52 cases were grade III. Osteoporosis was classified using the Singh index [21] : 18 cases were grade IV, 24 cases were grade III, 34 cases were grade II, and 10 cases were grade I.

The control group contained 44 patients, including 20 males and 24 females, with a mean age of 72.25 ± 5.54 years. The cause of injury was a fall in 34 cases, a traffic accident in 6 cases, and a pathological fracture in 4 cases. Fractures were classified using the Evans-Jensen classification: 4 cases were grade IIA, 13 cases were grade IIB, and 27 cases were grade III. Osteoporosis was classified using the Singh index: 9 cases were grade IV, 12 cases were grade III, 17 cases were grade II, and 6 cases were grade I.

The trial group contained 42 patients, including 21 males and 21 females with a mean age of 73.34 ± 5.24 years. The cause of injury was a fall in 33 cases, a traffic accident in 6 cases, and a pathological fracture in 3 cases. Fractures were classified using the Evans-Jensen classification: 6 cases were grade IIA, 11 cases were grade IIB, and 25 cases were grade III. Osteoporosis was classified using the Singh index: 9 cases were grade IV, 12 cases were grade III, 17 cases were grade II, and 4 cases were grade I.

Comparison of relevant indexes during and after surgery

Postoperative blood transfusion volume and the amount of drainage were higher in the trial group than in the control group (P < 0.05; [Table 3]).
Table 3: Comparison of relevant indexes during and after surgery in both groups

Click here to view


Comparison of efficacy at 6 months after surgery

The rate of excellent or good Harris hip scores was not significantly different between the trial and control groups (P > 0.05; [Table 4]).
Table 4: Comparison of efficacy [n(%)] at 6 months postoperatively in patients of both groups

Click here to view


Comparison of hip function before and after treatment

Harris scores were lower in the trial group than in the control group at 1 and 3 months postoperatively (P < 0.05; [Table 5]).
Table 5: Comparison of Harris scores before and after treatment in patients of both groups

Click here to view


Results of X-ray evaluation of the hip

At 6 months postoperatively, Brooker II heterotopic ossification appeared in 2 patients in the control group. Brooker I heterotopic ossification was observed in 2 patients and Brooker II heterotopic ossification in 1 patient in the trial group. In the control group, the hips of 34 patients were classified as grade A on Barrack's classification and the hips of 2 patients were grade B. During follow-up, no loosening or dislocation of the prosthesis occurred in any patients. The prostheses were all stable.

Comparison of adverse events

The incidence of adverse events was not significantly different between the two groups at 6 months after surgery (P > 0.05), but bone cement poisoning was found in four patients in the control group [Table 6].
Table 6: Comparison of adverse reactions in patients of both groups

Click here to view



  Discussion Top


Analysis of test results

Our partial results demonstrated that postoperative blood transfusion volume and the amount of drainage in the cementless prosthesis group were large. This was possibly because the bone cement inhibited bleeding in the medullary cavity, [22] thereby reducing postoperative blood transfusion volume and the amount of drainage in patients receiving the cemented prosthesis. There were no significant differences in operative time, intraoperative blood loss, or ambulation time between the trial and control groups, suggesting that the efficacy was similar between the use of the cemented and cementless prostheses. These findings further indicate that the biotype lengthening handle can also achieve good initial stability so that patients can get out of bed soon after surgery, thereby reducing the incidence of complications. During follow-up, no loosening or dislocation of the prosthesis occurred in any patients. The prosthesis was stable in all cases. These results verified that the long-term efficacy was similar between the groups.

At 1 and 3 months postoperatively (short term), hip function was good, the pain level was low, and the hip range of motion of the patients was considerable. However, no significant difference in the above indexes was found between the two groups at 6 months postoperatively, indicating similar efficacy between the cemented and cementless prostheses in the long term. Bone cement poisoning was seen in four patients in the control group. The changes in vital signs and biochemical indexes were strictly monitored before the operation. It was necessary to attempt prevention, early detection, and timely treatment of complications and medical comorbidities.

Limitations of the trial

The small sample size, short follow-up time, and single trial outcomes were a limitation of the study and may have affected the accuracy of the results, so our results need to be confirmed by future studies. [23],[24]

Evidence for contribution to future studies

The cemented and cementless prostheses were efficacious in elderly patients with unstable intertrochanteric fractures. Patients receiving the cemented prosthesis had a lower postoperative blood transfusion volume and less incisional drainage, but these patients also had an increased risk of bone cement poisoning.

 
  References Top

1.
Liang C, Peng R, Jiang N, Xie G, Wang L, Yu B. Intertrochanteric fracture: association between the coronal position of the lag screw and stress distribution. Asian J Surg. 2017 doi: 10.1016/j.asjsur.2017.02.003.  Back to cited text no. 1
    
2.
Kempegowda H, Richard R, Borade A, et al. Obesity is associated with high peri-operative complications among surgically treated intertrochanteric fracture of the femur. J Orthop Trauma. 2017 doi: 10.1097/BOT.0000000000000825.   Back to cited text no. 2
    
3.
Yoo JI, Ha YC, Lim JY, Kang H, Yoon BH, Kim H. Early rehabilitation in elderly after arthroplasty versus internal fixation for unstable intertrochanteric fractures of femur: systematic review and meta-analysis. J Korean Med Sci. 2017;32:858-867.   Back to cited text no. 3
    
4.
Yang S, Liu Y, Yang T, Zou J, Yang H. Early clinical efficacy comparison study of gamma3 nail, percutaneous compression plate (PCCP) and femoral head replacement (FHR) treatment on senile unstable intertrochanteric fractures. J Invest Surg. 2017 doi: 10.1080/08941939.2017.1282558.   Back to cited text no. 4
    
5.
Sun D, Park BS, Jang GI, Lee B. The fixation method according to the fracture type of the greater trochanter in unstable intertrochanteric fractures undergoing arthroplasty. Hip Pelvis. 2017;29(1):62-67.  Back to cited text no. 5
    
6.
Sonmez MM, Camur S, Erturer E, Ugurlar M, Kara A, Ozturk I. Strategies for proximal femoral nailing of unstable intertrochanteric fractures: lateral decubitus position or traction table. J Am Acad Orthop Surg. 2017 doi: 10.5435/JAAOS-D-15-00691.  Back to cited text no. 6
    
7.
Yoo JI, Ha YC, Lim JY, Kang H, Yoon BH, Kim H. Early rehabilitation in elderly after arthroplasty versus internal fixation for unstable intertrochanteric fractures of femur: systematic review and meta-analysis. J Korean Med Sci. 2017 doi: 10.3346/jkms.2017.32.5.858.  Back to cited text no. 7
    
8.
Wada K, Mikami H, Oba K, Yonezu H, Sairyo K. Cementless calcar-replacement stem with integrated greater trochanter plate for unstable intertrochanteric fracture in very elderly patients. J Orthop Surg (Hong Kong). 2017 doi: 10.1177/ 2309499016684749.  Back to cited text no. 8
    
9.
Arslan A, Utkan A, Koca TT. Results of a compression pin alongwith trochanteric external fixation in management of high risk elderly intertrochanteric fractures. Indian J Orthop. 2016;50:636-640.  Back to cited text no. 9
    
10.
Resch H, Krappinger D, Moroder P, Blauth M, Becker J. Treatment of periprosthetic acetabular fractures after previous hemi- or total hip arthroplasty: introduction of a new implant. Oper Orthop Traumatol. 2016;28:104-110.   Back to cited text no. 10
    
11.
Kashigar A, Vincent A, Gunton MJ, et al. Predictors of failure for cephalomedullary nailing of proximal femoral fractures. Bone Joint J. 2014;96-B:1029-1034.   Back to cited text no. 11
    
12.
Hoff P, Maschmeyer P, Gaber T, et al. Human immune cells' behavior and survival under bioenergetically restricted conditions in an in vitro fracture hematoma model. Cell Mol Immunol. 2013;10:151-158.  Back to cited text no. 12
    
13.
Renken F, Renken S, Paech A, Wenzl M, Unger A, Schulz AP. Early functional results after hemiarthroplasty for femoral neck fracture: a randomized comparison between a minimal invasive and a conventional approach. BMC Musculoskelet Disord. 2012;13:141.   Back to cited text no. 13
    
14.
Chen DW, Lin CL, Hu CC, Wu JW, Lee MS. Finite element analysis of different repair methods of Vancouver B1 periprosthetic fractures after total hip arthroplasty. Injury. 2012;43:1061-1065.   Back to cited text no. 14
    
15.
Yan M, Wang B, Li Y, Wang H, Lu Q, Zhou Y. Analysis of prosthesis-related complications after extensible semi-joint prosthesis replacement for lower limbs osteosarcoma in children. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2015;29:1194-1198.  Back to cited text no. 15
    
16.
Lv L, Niu XB, Zhang JJ, et al. Treatment of intertrochanteric fracture by hemiarthroplasty using long-stem cementless implant in aged patients. Zhonghua Guke Zazhi. 2012;32:637-641.  Back to cited text no. 16
    
17.
Castilian P, Bartra A, Vallro G, et al. Hip arthroplasty with conventional stem as rescue treatment after failed treatment of intertrochanteric hip fractures. Rev Esp Cir Ortop Tranmatol. 2013;57:194-200.  Back to cited text no. 17
    
18.
Barrack RL, Mulroy RD, Harris WH. Improved cementing techniques and femoral component loosening in young patients with hip arthroplasty. A 12-year radiographic review. J Bone Joint Surg Br. 1992;74:385-389.  Back to cited text no. 18
    
19.
Brooker AF, Bowerman JW, Robinson RA, et al. Ectopic ossiflcation following total hip replacement. J Bone Joint Surg (Br). 1973;55:1629-1632.  Back to cited text no. 19
    
20.
Jensen JS, Michaelsen M. Trochanteric femoral fractures treated with McLaughlin osteosynthesis. Acta Orthop Scand. 1975;46:795-803.  Back to cited text no. 20
    
21.
Singh M, Nagrath AR, Malni PS. Changes in trabecular pattern of the upper end of the femuran index of osteoporosis. J Bone Joint Surg Am. 1970;52:457-467.  Back to cited text no. 21
    
22.
Cheng SG, Wang WC, Xiao Y, et al. Cemented artificial femoral head arthroplasty treats elderly unstable intertrochanteric fracture. Zhongguo Zuzhi Gongcheng Yanjiu. 2015;19:8373-8378.  Back to cited text no. 22
    
23.
Liu GB, Zhang GP, Ren QY, et al. Classification of ankle injury on radiography and magnetic resonance imaging: study protocol for a retrospective, self-controlled, clinical trial with 3-month followup. Clin Transl Orthop. 2016;1:170-176.  Back to cited text no. 23
    
24.
Chen Y, Qu S, Ma G, Meng JH, Ni XL. Femoral nerve block prevents deep venous thrombosis of the lower extremity after knee arthroplasty: a single-center randomized controlled trial. Clin Transl Orthop. 2016;1:1-5.  Back to cited text no. 24
    

Author contributions
Study concept and design, manuscript writing, reading and checking: TMY. Experiment assistant: HLM. Both authors approved the final version of this paper.
Conflicts of interest
None declared.
Research ethics
The study protocol was approved by the Ethics Committee of Harrison International Peace Hospital of China (Approval number: 2013-37). The study was conducted in accordance with principles of the Declaration of Helsinki and Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidance for protocol reporting.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Plagiarism check
Checked twice by iThenticate.
Peer review
Externally peer reviewed.
Open access statement
This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
Additional file
Additional file 1: SPIRIT checklist (PDF136 kb).


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Methods/Design
Results
Discussion
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed9981    
    Printed895    
    Emailed0    
    PDF Downloaded754    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]