Clinical Trials in Degenerative Diseases

RESEARCH ARTICLE
Year
: 2018  |  Volume : 3  |  Issue : 2  |  Page : 38--44

Fenestration and debridement combined with percutaneous minimally invasive fibula implantation in the treatment of senile degenerative osteonecrosis of the femoral head: A study protocol for a non-randomized, controlled, clinical trial


Di Qin1, Xiao-Bo Wu1, Hui-Jie Li1, Li-Ying He1, Tao Wu1, Wen-Hui Ma1, Li-Xun Li2, Yong-Tai Han1,  
1 Third Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, China
2 Hebei Provincial Youfu Hospital, Shijiazhuang, Hebei Province, China

Correspondence Address:
Di Qin
Third Hospital, Hebei Medical University, Shijiazhuang, Hebei Province
China

Abstract

Background and objectives: Osteonecrosis of the femoral head is one of the common forms of senile degenerative osteoarthropathy. The hip preservation surgery techniques that are currently commonly used include femoral head fenestration, debridement and bone grafting through an anterior approach, and debridement and impaction bone grafting with fibula support through a lateral approach with subtrochanter drilling. These two techniques cause great trauma to the patients, and surgery costs are high. Femoral head collapse occurs easily after surgery. The course inhibition of necrosis of the femoral head and repair effect are not ideal. Thus, we hope to develop a new repair method that can make up for the shortcomings of conventional hip preservation surgery. We will observe the therapeutic effect of fenestration and debridement combined with percutaneous minimally invasive fibula implantation. This low-cost procedure for senile osteonecrosis of the femoral head should have little intraoperative trauma. We will determine if it also prevents postoperative femoral head collapse. Design: This is a prospective, multicenter, non-randomized, controlled, clinical trial. Methods: Seventy patients (117 hips) with senile degenerative osteonecrosis of the femoral head will be recruited from the Hebei Provincial Youfu Hospital and the Third Hospital of Hebei Medical University, Shijiazhuang, China. The patients will be allocated into three groups according to the repair method. (1) Patients in the drilling debridement group will undergo conventional debridement and impaction bone grafting with fibula support through a lateral approach with subtrochanter drilling. (2) Patients in the fenestration debridement group will undergo conventional femoral head fenestration, debridement, and bone grafting through an anterior approach. (3) Patients in the combination repair group will undergo fenestration, debridement, and impaction bone grafting combined with percutaneous minimally invasive fibula implantation. Each group will include 39 hips. Follow-up will be conducted for 12 months. Outcome measures: The primary outcome measure is the incidence of femoral head collapse on the affected side at 12 months after surgery. The secondary outcome measures are intraoperative blood loss, operation time, hospital costs, and Harris hip score for hip function before surgery and 6 and 12 months after surgery and the incidence of adverse reactions at 6 and 12 months after surgery. Discussion: Our results can verify whether the effect of fenestration and debridement combined with percutaneous minimally invasive fibula implantation is better than those of the other two types of conventional hip preservation techniques in the treatment of senile osteonecrosis of the femoral head. In addition, we will validate whether the combined method clearly inhibits postoperative femoral head collapse and improves hip function. Ethics and dissemination: This trial has been approved by the Ethics Committee of Third Hospital of Hebei Medical University of China (approval number: KE2016-011-1). The study protocol will be conducted in accordance with the Declaration of Helsinki, formulated by the World Medical Association. Written informed consent will be obtained from all participants. This trial was designed in January 2014. Ethics approval was done in December 2014. The recruitment of subjects will begin in June 2018. Samples and data will be collected from June 2018 to June 2019. Outcome measures will be analyzed in August 2019. This trial will be completed in December 2019. The results of the trial will be reported in a scientific conference or disseminated in a peer-reviewed journal. Trial registration: This trial was registered in the Chinese Clinical Trial Registry (registration number: ChiCTR1800015124).



How to cite this article:
Qin D, Wu XB, Li HJ, He LY, Wu T, Ma WH, Li LX, Han YT. Fenestration and debridement combined with percutaneous minimally invasive fibula implantation in the treatment of senile degenerative osteonecrosis of the femoral head: A study protocol for a non-randomized, controlled, clinical trial.Clin Trials Degener Dis 2018;3:38-44


How to cite this URL:
Qin D, Wu XB, Li HJ, He LY, Wu T, Ma WH, Li LX, Han YT. Fenestration and debridement combined with percutaneous minimally invasive fibula implantation in the treatment of senile degenerative osteonecrosis of the femoral head: A study protocol for a non-randomized, controlled, clinical trial. Clin Trials Degener Dis [serial online] 2018 [cited 2024 Mar 29 ];3:38-44
Available from: https://www.clinicaltdd.com/text.asp?2018/3/2/38/235146


Full Text

 Introduction



Research background

Osteonecrosis of the femoral head (ONFH) is a common bone and joint disease in adults older than 60 years. With the development of an aging society, the incidence of ONFH is increasing yearly owing to degeneration of the hip joint and slowed reactions of the muscle group surrounding the hip. Moreover, as these symptoms are prolonged, morbidity is increased.[1],[2],[3],[4],[5] Studies regarding surgical treatment of senile ONFH published from 2003 to 2012 are listed in [Table 1].[6],[7],[8]{Table 1}

Hip preservation surgery is commonly selected by physicians for treatment of ONFH. There are two types of hip preservation surgery. The first type aims at recovery and reconstruction of blood circulation of the femoral head, such as core decompression, transplantation of an iliac bone flap with a vascular pedicle, and fibula autograft with an anastomotic blood vessel. The therapeutic effects of these methods on joint surface collapse are poor.[9],[10],[11],[12],[13],[14] The second type aims at prevention of collapse with mechanical support, such as debridement and bone grafting, and impaction bone grafting and tantalum rods/allogeneic fibula implantation with subtrochanter drilling. However, the thoroughness and precision of debridement and the impaction effect are limited by subtrochanter drilling.[15],[16],[17] The efficacy of other repair methods remains to be verified, including interventional vascular recanalization, stem cell transplantation, and vascular growth factor introduction.

Novelty of this study

The proposed method, fenestration and debridement combined with percutaneous minimally invasive fibula implantation, is characterized by decompression, precise and complete debridement, maximum support of the joint surface, and elimination of focus by impaction bone grafting, and the fibula strengthens the joint surface and prevents further collapse. In addition, it is not necessary to remove the lesions through the femoral neck bone tunnel, so large incisions are not required. Simply implanting the fibula into the percutaneous canal can remarkably reduce the surgical trauma.

[INLINE:1]

Main objectives

The aim of this trial is to compare two conventional hip preservation surgeries with the fenestration and debridement combined with percutaneous minimally invasive fibula implantation in the treatment of senile degenerative ONFH, and to determine whether the combined method can effectively reduce trauma, prevent postoperative femoral head collapse, and restore hip function.

 Methods/Design



Study design

This is a prospective, multicenter, non-randomized, controlled, clinical trial.

Study setting

Hebei Provincial Youfu Hospital and Third Hospital of Hebei Medical University, Shijiazhuang, China.

Recruitment

Our recruitment notice contains details of the study and will be posted on the bulletin board of our institutions. Patients participating in this study will be partially exempted from imaging-related costs at follow-up. Patients or family members (will not participate) of patients who are interested in participating in the study can directly call the study leader. After screening, based on the inclusion and exclusion criteria and provision of informed consent, these patients will be enrolled in our study.

Participant selection

Seventy patients (117 hips) with senile degenerative ONFH will be recruited.

Inclusion criteria

Patients who meet all of the following criteria will be considered for study inclusion:

ONFH rated as Association Research Circulation Osseous (ARCO) stages 2–3. Stage 2: no crescent sign, X-ray revealed sclerosis, trabecular defect or regional cystic change; stage 3: crescent sign, flatten femoral head joint surface, with or without femoral head collapse[18] Age 60−80 years Muscle strength grade 5 in the affected limb using Lovett’s muscle testing, grade 0: no measurable muscle contraction; grade 1: slight contraction, but it does not cause joint movement; grade 2: full range motion of joints under weight loss; grade 3: can resist gravity for full range movement, but cannot resist resistance; grade 4: resists gravity and general resistance; grade 5: anti-gravity, anti-full resistance First ONFH surgery Provision of informed consent

Exclusion criteria

Patients who meet one or more of the following conditions will be excluded from the study:

History of hip trauma Pathological fracture of the hip Hip infection

Randomization and blinding

Limited by differences in each patient’s condition and economic status, this study will not select random groups. According to the patient’s condition and the wishes of the patient and family, 117 hips will be equally assigned to 3 groups (39 hips per group). No allocation concealment or blinding method will be used.

Interventions

Fenestration and debridement combined with percutaneous minimally invasive fibula implantation

A longitudinal incision (approximately 5 cm) will be made approximately 2 cm below the anterior inferior iliac spine. The articular capsule will be isolated and exposed in the space between the sartorius and tensor fasciae latae and between the rectus femoris and gluteus medius. The articular capsule will be longitudinally incised. Fenestration will be performed at the junction of the head and neck (approximately 1.0 cm × 1.5 cm). In accordance with preoperative X-ray positioning, dead bone will be removed directionally using a curette or surgical drill. The surface of the collapsed joint will be supported by impaction. After flushing under pressure, allogenic cancellous bone (rehydration of freeze-dried cancellous bone without cortex using physiological saline before use) will be implanted and impacted. A guide pin will be percutaneously inserted at a 45º angle with the lower limb at approximately 7 cm below the greater trochanter. Using fluoroscopy, the direction of the guide pin will be adjusted, and the guide pin will reach the site of the bone graft. A specially made sleeve along the guide pin will be pushed into the working tunnel. The implanted cancellous bone will be impacted again with a beating device through the working tunnel. If necessary, bone mass will be increased. After measuring the depth of the bone tunnel, the allogeneic fibula will be trimmed and beaten into the bone tunnel. A bone block for fenestration will be put back in its original position. The precise surgical process is shown in [Figure 1].{Figure 1}

Key points in the repair: 1) During fenestration and debridement, dead bone will be thoroughly removed, and normal bone will be kept. 2) The strength and direction of support will be appropriate for the collapsed joint surface. It is necessary to provide adequate support and also prevent articular surface rupture. 3) The length of the fibula will be adjusted so that the fibula can be implanted firmly.

Fenestration, debridement, and bone grafting

The precise procedure is identical to that described in [Figure 1].

Debridement and impaction bone grafting with fibula support through a lateral approach with subtrochanter drilling

1) An approximately 10 cm incision will be made below the greater trochanter. The subcutaneous fascia latae will be incised in order. The vastus lateralis will be separated to expose the greater trochanter and adjacent femoral shaft. 2) A guide pin will be inserted in the femoral neck at a 45º angle with the femoral shaft from approximately 2 cm below the greater trochanter. 3) Using fluoroscopy, the direction of the guide pin will be adjusted, and the guide pin will point to the site approximately 0.5 cm below the articular cartilage in the necrotic area. The hole will be expanded to approximately 11-mm in diameter with a hollow drill and reamer. After scraping the dead bone with a curette, cancellous bone will be implanted and impacted. The fibula will be implanted as above. Finally, the incision will be sutured.

Processing after repair

Patients will perform self-functional exercise on the bed on day 2 after surgery. Partial weight bearing will be allowed at 3 months after surgery, and full weight bearing at 6 months.

Outcome measures

Primary outcome measure

The incidence of femoral head collapse on the affected side at 12 months after surgery is a primary outcome measure. Femoral head collapse refers to the summation of numerous small compression fractures in the necrotic site of the femoral head, as osteocytes begin to sink, and the ability to withstand the pressure declines after femoral head necrosis reaches a certain level. Subsidence of the femoral head necrosis implies that the mechanical properties of the subchondral bone plate will fail, eventually leading to impaired hip dysfunction. X-ray evaluation of post-operative collapse will be performed in accordance with a previous study.[19] Collapse will be graded from I to IV. Grade I: the shape of the femoral head remains round. According to the repair, there are two sub-classifications. Grade Ia: repair of the necrotic region, significant narrowing; grade Ib: no repair or progression of necrosis. Grade II: occurrence of femoral head collapse or the collapse height < 2 mm compared with before treatment, repair of necrotic region, no significant degeneration of the hip, and no significant narrowing of the joint space. Grade III: femoral head collapse height 2–4 mm compared with that before treatment; the repair is not dramatic; there is no obvious osteoarthritis. Grade IV: femoral head collapse height > 4 mm compared with before treatment, hip space narrowed. The standard of collapse occurrence: a collapse above grade II revealed by X-ray films in the anteroposterior frog position. The incidence of femoral head collapse is equal to the number of hips with femoral head collapse/the total number of operated hips in each group × 100%.

Secondary outcome measures

Intraoperative blood loss: The total amount of bleeding during surgery will be assessed. The greater the amount of bleeding, the worse the quality of the operation. Operation time: The time needed for the three kinds of hip preservation surgeries will be evaluated. The longer the operation time, the worse the quality of the operation. Hospital costs: The total cost of treatment from admission to discharge will be assessed. Harris hip score for hip function will be assessed before surgery and at 6 and 12 months after surgery: A maximum Harris score is 100: a score > 90 is considered excellent, 80-89 is good, 70–79 is average, and < 70 is poor. A high score indicates good hip function. The incidence of adverse reactions will be evaluated at 6 and 12 months after surgery and is equal to the number of patients with adverse reactions/total number of patients × 100%.

The schedule of outcome measurement assessments is shown in [Table 2].{Table 2}

Adverse events

Adverse reactions, including incisional pain, hip pain, infection, mental disorders, and femoral head collapse, will be recorded. If severe adverse reactions occur, the investigators will report the details, including the date and type of occurrence and the measures taken to treat the adverse events, to the trial leader and the ethics committee within 24 hours.

Trial procedure

This trial aims to compare postoperative hip function and femoral head collapse indexes using three types of hip preservation surgeries. A novel method of hip preservation for the treatment of femoral head necrosis will be evaluated to determine if it has a better effect, is a simpler operation, and creates less trauma. [Figure 2] shows the flow chart of the study protocol.{Figure 2}

Sample size

In accordance with our experience, we hypothesize that the incidence of femoral head collapse at postoperative 12 months will be 10% in the combination repair group and 40% in the drilling debridement group and fenestration debridement group. Taking β = 0.1 and power = 90% with a significance level of α = 0.05, the final effective sample size of n = 32 hips per group will be calculated using PASS 11.0 software (PASS, Kaysville, UT, USA). If we assume a loss rate of 20%, we will totally require 117 hips (n = 39 hips per group). After screening according to the inclusion and exclusion criteria, we will include 70 patients (117 hips).

Statistical considerations

Data description

All data will be analyzed using SPSS 19.0 software (IBM, Armonk, NY, USA) according to the intention-to-treat principle. Normally distributed measurement data will be expressed as the mean ± SD, minimum and maximum. Non-normally distributed measurement data will be expressed as the lower quartile (q1) and median and upper quartiles (q3). Enumeration data will be presented as percentages.

Selection of statistical methods

The incidences of femoral head collapse and adverse reactions will be analyzed with Pearson’s chi-square test. Intraoperative blood loss, operation time, and Harris score among multiple groups at the same time point will be compared using one-way analysis of variance and Student-Newman-Keuls test. Intraoperative blood loss, operation time, and Harris score in each group at various time points will be compared using repeated measures analysis of variance. The significance level will be α = 0.05.

Data sets

Included subjects will be assigned to the full analysis set and per protocol set.

Full analysis set: as per the intention-to-treat principle, this will be the data set consisting of all patients. The test requires a complete follow-up of for all randomized subjects. For subjects whose baseline data for the primary outcome measure are missing, or have poor compliance, and those who do not have any follow-up evaluations, their data will be eliminated from the full analysis set. When the full analysis set is selected for statistical analysis and for the estimation of missing values for the primary outcome measure, the last observation-carried-forward principle will be used for data conversion.

Per protocol set: as per the per protocol principle, all subjects who completely accorded with the study design will be included. Case data will be excluded from the study if any of the following are found: 1) Subjects do not meet the inclusion criteria or do meet exclusion criteria; 2) the main curative effect measure was determined beyond the time window and is considered a violation of the test program.

Data collection and management

Data collection

Case report forms will be recorded, collected, and summarized. Above data will be processed using Epidata software and then recorded electronically using a double-data entry strategy.

Data management

The electronic database will be accessible and locked only by the project manager. This arrangement will not be altered. The Third Hospital of Hebei Medical University of China will preserve all of the data regarding this trial.

Audits

Data monitoring committee composition

The data monitoring committee is responsible for periodically evaluating the research progress, safety data, and effectiveness endpoint and makes recommendations to the sponsor on whether to continue, adjust, or stop the trial.

Investigator qualification

All surgeons participating in this study have a wealth of hip replacement experience. Surgeons should fully understand the structural features of implant products and the use of the supporting tools. Surgeons who conduct Harris score and imaging evaluation should have received professional training and have extensive experience in evaluation. The researchers should have unified data recording methods and judgment criteria. Experimental data processing and statistical calculations will be performed by statisticians.

Auditing

After the experiments, the results of the provisional safety analysis test will be obtained by the independent ethics committee of the Third Hospital of Hebei Medical University to confirm the integrity and authenticity of all the data records.

Compensation to study participants

During the clinical trial, patients can learn about and obtain the most recent treatment information and will be followed up closely by the professional medical team for free. There will be no test or registration fees at follow-up.

Compensation to study participants with adverse events

A compensation agreement will be assigned before the start of the clinical trial at the discretion of the sponsor and investigators after thorough consideration, and will be used if the study participants require economic compensation. If drug-related adverse reactions occur, study participants will be eligible for economic compensation as per the assigned economic compensation agreement.

Ethics and dissemination

This trial has been approved by the Ethics Committee of Third Hospital of Hebei Medical University of China (approval number: KE2016-011-1). The study protocol will be conducted in accordance with the Declaration of Helsinki, formulated by the World Medical Association and will be reported in line with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) checklist[20] (Additional file 1 [SUPPORTING:1]). Written informed consent will be obtained from all participants. One staff member will transcribe, date, and upload the trial outcomes to a dedicated computer. An investigator will schedule, check, and lock up the data. The data will be password-protected and not altered for future reference. No person, other than an authorized researcher, may be in contact with it. The results of the trial will be reported in a scientific conference or disseminated in a peer-reviewed journal.

 Trial Status



This study protocol has been designed, and the recruitment of subjects will begin in June 2018.

 Discussion



Contributions and problems of previous studies in this field

In China, the lack of medical facilities, the economic conditions in some areas, the unreasonable use of hormone drugs, delays in diagnosis, alcoholism, and poor living conditions lead to several patients developing ONFH every year. Hip replacement as an end treatment, owing to the high cost and high technical requirements, is difficult to carry out in the primary hospitals. Combined treatments, if effective, have a low cost and minimize trauma and would be suitable for hip preservation surgery in primary hospitals. Therefore, the combined method has the vast majority of the actual needs of primary health care institutions and good prospects.

Characteristics of this study protocol

This prospective, randomized, controlled clinical trial will have a sufficient sample size. Two conventional hip preservation surgeries will be used as controls. Our data can objectively verify the credibility of the therapeutic effect of the combined treatment for senile degenerative ONFH.

Limitations of this study

A standard scheme of fenestration and debridement combined with percutaneous minimally invasive fibula implantation still needs to be further strengthened. Randomization is not used, and the follow-up time is short. The long-term effects need to be observed. This is a single-center study, which will affect the universality of the test results.

Significance of this study

Fenestration and debridement combined with percutaneous minimally invasive fibula implantation for senile degenerative ONFH minimizes trauma, is a simple and safe operation, has no special requirements for medical devices, and is easily conducted in primary hospitals. The repair effect is good. This method can effectively delay or avoid changing hips, saving medical expenses. The authors believe that it will have a good clinical application prospect.

Additional file

Additional file 1: SPIRIT checklist.

Author contributions

Study design: LXL. Subject recruitment, data collection and analysis, and manuscript writing: LXL and DQ. All authors approve the final version of the manuscript.

Conflicts of interest

The authors declare that the research is conducted in the absence of any commercial or financial relationships that can be construed as a potential conflict of interest.

Financial support

None.

Institutional review board statement

This trial has been approved by the Ethics Committee of Third Hospital of Hebei Medical University of China (approval number: KE2016-011-1). The study follows international and national regulations in accordance with the Declaration of Helsinki and relevant ethical principles.

Declaration of patient consent

The authors certify that they will obtain patient consent forms. In the form, patients will give their consent for their images and other clinical information to be reported in the journal. The patients will 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.

Reporting statement

This study was reported in line with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) checklist.

Biostatistics statement

The statistical methods of this study were reviewed by the biostatisticians of the Third Hospital of Hebei Medical University, China.

Copyright transfer agreement

The Copyright License Agreement has been signed by all authors before publication.

Data sharing statement

Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures, and appendices) will be in particular shared. Study protocol and informed consent form will be available. The data will be available immediately following publication without end date. Results will be disseminated through presentations at scientific meetings and/or by publication in a peer-reviewed journal. Anonymized trial data will be available indefinitely at www.figshare.com.

Plagiarism check

Checked twice by iThenticate.

Peer review

Externally peer reviewed.

References

1Onyemaechi NO, Enweani UN, Maduka CO. Musculoskeletal complications of sickle cell disease in Enugu, Nigeria. Niger J Med. 2011;20:456-461.
2Roposch A, Liu LQ, Offiah AC, Wedge JH. Functional outcomes in children with osteonecrosis secondary to treatment of developmental dysplasia of the hip. J Bone Joint Surg Am. 2011;93:e145.
3Mukisi-Mukaza M, Saint Martin C, Etienne-Julan M, Donkerwolcke M, Burny ME, Burny F. Risk factors and impact of orthopaedic monitoring on the outcome of avascular necrosis of the femoral head in adults with sickle cell disease: 215 patients case study with control group. Orthop Traumatol Surg Res. 2011;97:814-820.
4Tan A, Smulders YC, Zöphel OT. Use of remodeled femoral head allograft for tarsal reconstruction in the treatment of müller-weiss disease. J Foot Ankle Surg. 2011;50:721-726.
5Xu M, Peng D. Mesenchymal stem cells cultured on tantalum used in early-stage avascular necrosis of the femoral head. Med Hypotheses. 2011;76:199-200.
6Fuchs B, Knothe U, Hertel R, Ganz R. Femoral osteotomy and iliac graft vascularization for femoral head osteonecrosis. Clin Orthop Relat Res. 2003 DOI: 10.1097/01.blo. 0000071756.07450.76.
7Yang S, Wu X, Xu W, et al. Structural augmentation with biomaterial-loaded allograft threaded cage for the treatment of femoral head osteonecrosis. J Arthroplasty. 2010;25:1223-1230.
8Sen RK, Tripathy SK, Aggarwal S, et al. Early results of core decompression and autologous bone marrow mononuclear cells instillation in femoral head osteonecrosis: a randomized control study. J Arthroplasty. 2012;27:679-686.
9Aimaiti A, Wufuer M, Wang YH, Saiyiti M, Cui L, Yusufu A. Can bisphenol A diglycidyl ether (BADGE) administration prevent steroid-induced femoral head osteonecrosis in the early stage? Med Hypotheses. 2011;77:282-285.
10Liu Y, Zhao D, Wang WM, Wang BJ, Zhang Y, Li ZG. Hemodynamic changes in osteonecrosis treatment of the femoral head with iliac bone flaps pedicled with the lateral femoral circumflex artery ascending branch: a 10-year report. Technol Health Care. 2016;24 Suppl 2:S493-498.
11Zeng YR, He S, Feng WJ, et al. Vascularised greater trochanter bone graft, combined free iliac flap and impaction bone grafting for osteonecrosis of the femoral head. Int Orthop. 2013;37:391-398.
12Zhao DW, Wang BJ. Treatment of osteonecrosis of femoral head with minimally invasive vascularized bone grafting. Zhonghua Yi Xue Za Zhi. 2007;87:2036-2040.
13Gaskill TR, Urbaniak JR, Aldridge JM 3rd. Free vascularized fibular transfer for femoral head osteonecrosis: donor and graft site morbidity. J Bone Joint Surg Am. 2009;91:1861-1867.
14Vail TP, Urbaniak JR. Donor-site morbidity with use of vascularized autogenous fibular grafts. J Bone Joint Surg Am. 1996;78:204-211.
15Cilla M, Checa S, Preininger B, et al. Femoral head necrosis: A finite element analysis of common and novel surgical techniques. Clin Biomech (Bristol, Avon). 2017;48:49-56.
16Tran TN, Warwas S, Haversath M, et al. Experimental and computational studies on the femoral fracture risk for advanced core decompression. Clin Biomech (Bristol, Avon). 2014;29:412-417.
17Song WS, Yoo JJ, Kim YM, Kim HJ. Results of multiple drilling compared with those of conventional methods of core decompression. Clin Orthop Relat Res. 2007;454:139-146.
18Chinese Medical Association Orthopaedics Branch microscopic repair Section. Guidelines for clinical diagnosis and treatment of adult osteonecrosis of femoral head (2016). Zhonghua Guke Zazhi. 2016;36:945-954.
19Zhang Y, Liu YW, Feng LZ, He W. Comparison of effects of tantalum rod and allogeneic fibula transplantation in treatment of patients with early non-traumatic osteonecrosis of femoral head during hip-preserving surgery. Shandong Yiyao. 2015;55:5-7.
20Chan AW, Tetzlaff JM, Altman DG, et al. SPIRIT 2013 statement: defining standard protocol items for clinical trials. Ann Intern Med. 2013;158:200-207.