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

Tie-miao yu, Hui-ling Miao

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

INTRODUCTION

Background

Intertrochanteric fractures are common types of hip fractures.1,2With 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.3-6Because the aging population in China is increasing gradually, the incidence of unstable intertrochanteric fractures is increasing year by year.7-9Clinically, 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.10,11The 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.12-14The most commonly used artificial joint replacement types include cemented and cementless prostheses,15but 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

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 eff icacy and safety of two kinds of prostheses in the treatment of unstable intertrochanteric fractures in elderly patients.

Figure 1shows the flow chart describing the study protocol.

Strengths and limitations

? 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.

? The small sample size.

? Short follow-up time.

? Single trial outcomes.

Figure 1: Flow chart of trial protocol.

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 theDeclaration 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).

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 examination16

? 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 inTable 1.

Table 1: Baseline data and general disease history of patients

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. Takingβ= 0.2 and Power = 80%with a significance level ofα= 0.05, the sample size ofn= 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 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,17hip 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 classifiedviathe 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.18The quality of bone cement was graded using Barrack’s classification.19Grade 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 inTable 2.

Table 2: Timing of outcome assessments

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-totreat 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-samplettests 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 atα= 0.05.

RESULTS

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 classification20: 10 cases were grade IIA, 24 cases were grade IIB, and 52 cases were grade III. Osteoporosis was classified using the Singh index21:18 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).

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 3: Comparison of relevant indexes during and after surgery in both groups

Table 4: Comparison of efficacy [n(%)] at 6 months postoperatively in patients of both groups

Table 5: Comparison of Harris scores before and after treatment in patients of both groups

Table 6: Comparison of adverse reactions in patients of both groups

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).

Results of X-ray evaluation of the hip

At 6 months postoperatively, Brooker II heterotopic ossif ication 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).

DISCUSSION

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,22thereby 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.

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 theDeclaration of Helsinkiand 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 patientconsent 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).

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