Advanced core decompression, a new treatment option of avascular necrosis of the femoral head--a first follow-up

COVID-19-Associated Bilateral Avascular Necrosis of Femoral Head in a Young Male Without Corticosteroid Exposure: A Case Report

Avascular necrosis (AVN), also known as osteonecrosis, ischemic bone necrosis, or aseptic necrosis, is a progressive bone disease marked by the deterioration of bone tissue due to compromised blood flow in the subchondral region. AVN is typically caused by disruptions in vascular supply, intravascular blockages, or pressure on blood vessels, leading to diminished circulation. This condition predominantly affects the long-bone epiphysis in weight-bearing joints, particularly impacting the femoral head. The ongoing global health challenge posed by the novel coronavirus disease (COVID-19) has raised awareness of its diverse clinical manifestations. While pulmonary dysfunction remains a hallmark, reports of AVN of the hip have emerged in association with COVID-19 infection. Despite existing literature documenting cases of unilateral and bilateral femoral head necrosis associated with COVID-19 infection, it is noteworthy that corticosteroid use has been identified as a significant contributing factor to the development of this condition. Here, we present a case of bilateral AVN of the femoral head in a young individual linked solely to COVID-19 infection. Existing case records show only a handful of instances where COVID-19 has led to avascular necrosis, all involving either older individuals or those with notable risk factors. What sets our case apart is that the patient is young and lacks any significant risk factors. This report aims to propose a credible connection between COVID-19 infection and femoral head osteonecrosis in young patients not exposed to steroid treatment.

Prognostic factors in the management of osteonecrosis of the femoral head: A systematic review

BACKGROUND

Several hip preserving techniques have been described for the management of osteonecrosis of the femoral head (ONFH). This systematic review identified prognostic factors in the treatment of ONFH that are associated with treatment failure and conversion to total hip arthroplasty (THA).

MATERIAL AND METHODS

This study followed the PRISMA guidelines. The literature search was conducted in November 2021. All clinical trials comparing two or more treatments for femoral head osteonecrosis were accessed. A multivariate analysis was performed to investigate the association between baseline characteristics and the surgical outcome. A multiple linear model regression analysis through the Pearson Product-Moment Correlation Coefficient (r) was used.

RESULTS

Data from 88 articles (6112 procedures) were retrieved. Female gender was associated with increased time to THA (P = 0.03) and reduced rate of THA (P = 0.03). Longer symptom duration before treatment was associated with shorter time to failure (P = 0.03). Increased pre-treatment VAS was associated with reduced time to failure (P = 0.03) and time to THA (P = 0.04). Reduced pre-treatment hip function was associated with increased rate of THA (P = 0.02) and failure (P = 0.005). Patient age and BMI, aetiology, time from surgery to full weight bearing and the side did not show evidence of a statistically significant association with the surgical outcome.

CONCLUSION

Male gender, longer symptom duration before treatment, higher VAS scores, and lower HHS scores were negative prognostic factors after treatment for osteonecrosis of the femoral head.

Bone tissue engineering for treating osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a devastating and complicated disease with an unclear etiology. Femoral head-preserving surgeries have been devoted to delaying and hindering the collapse of the femoral head since their introduction in the last century. However, the isolated femoral head-preserving surgeries cannot prevent the natural progression of ONFH, and the combination of autogenous or allogeneic bone grafting often leads to many undesired complications. To tackle this dilemma, bone tissue engineering has been widely developed to compensate for the deficiencies of these surgeries. During the last decades, great progress has been made in ingenious bone tissue engineering for ONFH treatment. Herein, we comprehensively summarize the state-of-the-art progress made in bone tissue engineering for ONFH treatment. The definition, classification, etiology, diagnosis, and current treatments of ONFH are first described. Then, the recent progress in the development of various bone-repairing biomaterials, including bioceramics, natural polymers, synthetic polymers, and metals, for treating ONFH is presented. Thereafter, regenerative therapies for ONFH treatment are also discussed. Finally, we give some personal insights on the current challenges of these therapeutic strategies in the clinic and the future development of bone tissue engineering for ONFH treatment.

Optimal drilling at femoral head-neck junction for treatment of the femoral head necrosis: Experimental and numerical evaluation

BACKGROUND

Advanced core decompression (ACD) is a relative new technique for treatment of early stages of avascular femoral head necrosis. Although it is a promising treatment option, there is a need to modify this technique for achieving higher hip survival rates. An idea was to combine this technique with the lightbulb procedure in order to get a complete removal of the necrosis. This study aimed at evaluating the fracture risk of the femora treated by the combined Lightbulb-ACD technique as the basis for clinical application.

METHODS

Subject-specific models were generated from CT scan data of five intact femora. Several treated models were then created from each intact bone and simulated during normal walking activity. Biomechanical testing was additionally performed on 12 pairs of cadaver femora to confirm the simulation results.

FINDINGS

The finite element results revealed that the risk factor of the treated models with a 8 mm-drill increased, but was not significantly greater than that of their corresponding intact models. However, for the femur treated with a 10 mm-drill, the risk factor increased significantly. Fracture always initiated on the femoral neck, i.e. it was either subcapital or transcervical fracture. Our biomechanical testing results correlated well with the simulation data which confirmed the usefulness and effectiveness of the bone models.

INTERPRETATION

The combined Lightbulb-ACD technique using a 10 mm drill increased the fracture risk of femur postoperatively. A drill of up to 8 mm at the anterior head-neck junction did not however lead to the weakening of the femur so that full load bearing may be possible.

[The importance of removing osteonecrosis during treatment of femoral head osteonecrosis]

Atraumatic femoral head necrosis (aFHN) in adults is estimated to be the leading cause of approximately 10% of all hip prosthesis implantations. Due to the relatively frequent occurrence of aFHN at a young age, the possibility of a joint-preserving intervention should be examined. This includes the classic "core decompression" and modifications based on it. There are different data on the success rates of this method. Reasons for treatment failure could include a lack of clearance of the necrosis zone. The clearance of the necrosis zone is taken into account by alternative surgical procedures for the treatment of aFHN. These are the "trap-door procedure", the "light-bulb procedure" and "advanced core decompression". The current state of knowledge on these procedures is reviewed in this keynote article. It is shown that the extensive excision of femoral head necrosis is of particular importance. None of the procedures mentioned can currently be recommended in preference over the others.

Effectiveness of Calcium Sulfate and Hydroxyapatite Composite in Collapse Prevention in Osteonecrosis of Femoral Head

Introduction

Calcium-sulfate-hydroxyapatite bioceramics have been widely used as void fillers in bone. However, their effectiveness as void fillers in core decompression for osteonecrosis of the femoral head (ONFH) in preventing femoral head collapse prevention has limited evidence. The current study investigates the effectiveness of calcium-sulfate-hydroxyapatite bioceramics as a void filler in the core decompression procedure for ONFH.

Methods

We retrospectively reviewed the clinical and radiological records of ONFH patients that underwent core-decompression using either autologous iliac crest cancellous bone graft or calcium-sulfate-hydroxyapatite bioceramic paste as void fillers with at least one-year follow-up. The primary outcome of this study was the radiological progression of collapse in the last available standard anteroposterior (AP) radiographs of the hip. The collapse progression was compared between the two groups based on void fillers.

Results

This study included patient records with 44 hip joints that underwent core decompression. There were five female and 33 male patients. The mean age was 29.1±6.3 years. The mean follow-up duration was 21.4±3.4 months. No significant differences in collapse progression were observed between the two groups based on void fillers.

Conclusion

The use of calcium-sulfate-hydroxyapatite as a void filler in core decompress for ONFH is not superior to the autologous cancellous bone in terms of collapse prevention and mechanical support. Further modifications in the core decompression techniques and well-planned prospective studies would help establish sound recommendations.

Hip joint mechanics in patients with osteonecrosis of the femoral head following treatment by advanced core decompression

BACKGROUND

Osteonecrosis of the femoral head is a serious disease which, if left untreated, leads to destruction of the affected hip joint. For treatment of early stages of this disease, core decompression is the most common procedure. This study investigated the influence of the necrotic lesion and core decompression on the stress pattern in the hip joint using finite element analysis.

METHODS

Subject-specific models were generated from CT scan data of 5 intact hips. For each intact hip, twelve affected hip models were created by imposing a necrotic lesion in the femoral head, and four treated models were then created from four affected ones with central lesion, respectively. Treated models were created by supposing that the defect zone and the drill canal were filled with a bone substitute. Totally 105 hip models from three groups (intact, affected and treated) were simulated during normal walking activity.

FINDINGS

Necrotic lesion modified the stress distribution within the femoral head. Peak stress increased significantly up to 186% in mean in hips with a large lesion indicating an increased risk of femoral head collapse. Additionally, the presence of a medium to large necrosis altered significantly stress values (P < 0.05) and pattern in the articular cartilage. Our study revealed that advanced core decompression can recover normal cartilage stress values and pattern in treated joint.

INTERPRETATION

The presence of a large lesion increased the risk of femoral head collapse. Advanced core decompression with bone grafts can restore normal cartilage mechanics in hip postoperatively.

Corticosteroid induced avascular necrosis and COVID-19: The drug dilemma

The severe and life-threatening nature of the COVID-19 infection, the ARDS (acute respiratory distress syndrome) as well as the cytokine storm induced by the infection, commands lifesaving high doses of steroid therapy. As in all pharmacological therapies adverse effects are present. One such adverse effect which is being reported is corticosteroid induced avascular necrosis of the femoral head/ osteonecrosis of the femoral head. It must be noted that AVN principally affects the femoral head and most commonly the anterolateral aspect thereof as it is the crux of weight bearing.  Corticosteroids induce fat mobilization and this thus innately enhances the likelihood of fat emboli developing from the liver to occlude minor blood vessels in the femur, this thereby compromises the microvascular environment. Superadded to this the steroid therapy disrupts calcium metabolism and homeostasis which induces hypertrophy in the intramedullary fat cells, Gaucher cells and inflammatory cells; whilst increasing the activity of osteoclasts, thus increasing bone resorption and decreasing calcium uptake and deposition; ultimately leading to an insufficiency in the trabecular and cortical bone. This insufficiency thus equates to an increased intraosseous pressure which impedes intramedullary circulation and results in avascular necrosis.  It is evident that avascular necrosis is directly caused by high dose steroid therapy, however the case reports have very clearly indicated that the rapid onset of AVN post recovery from the COVID-19 infection cannot be solely attributed to steroid therapy and that another benefactor induced by the COVID-19 infection is at play. It is thus vital for treating physicians to take cognisance of this adverse effect post recovery and therefore should ensure that prophylactic bisphosphonate therapy is initiated timeously and congruently.

Concentric Circle Technique for Assessment of Femoral Head Deficiency in Osteonecrosis of Femoral Head

Introduction

There is a lack of standardized objective tools to assess collapse for osteonecrosis of the femoral head (ONFH) patients’ follow-up. We describe a quantitative technique of collapse assessment using a superimposed concentric circular ring matching the intact part of the femoral head in anteroposterior (AP) radiographs.

Methods

We retrospectively analyzed 30 normal femoral heads and 30 ONFH (15 pre-collapse,15 post-collapse) in anteroposterior hip radiographs. A best-fitting circle was superimposed on articular margins of the femoral head and the maximum width of the deficient zone of the femoral head (not matching the circle) was measured. The width (pW) was measured as percentage-width in proportion to the circle’s diameter. The findings were compared among normal and ONFH radiographs. Intraclass correlation coefficients were calculated for intraobserver and interobserver reliability of the measurements.

Results

The mean femoral head deficiencies predicted by pW were 0.2±0.5% for normal hip, 2.8±1.1% for pre-collapse, and 8.9±3.8% for post-collapse radiographs. We observed significant differences in the measurements of pW among the control group, pre-collapse and post-collapse groups. Interobserver and intraobserver reliabilities for the measurements were high.

Conclusion

The described concentric circle technique is a simple and reliable method for objective assessment of subtle alterations in the sphericity of the femoral head and can be helpful for the radiographic follow-up of ONFH patients.

Combining autologous bone marrow buffy coat and angioconductive bioceramic rod grafting with advanced core decompression improves short-term outcomes in early avascular necrosis of the femoral head: a prospective, randomized, comparative study

Background

Treatment of avascular necrosis of the femoral head (ANFH) in young patients remains a clinical challenge. A current controversy is whether hip-preserving surgery results in better outcomes. The adverse effects of hip-preserving surgery are associated with the fill material for the necrotic areas. This study aims to evaluate the early effects of autologous bone marrow buffy coat (BBC) and angioconductive bioceramic rod (ABR) grafting with advanced core decompression (ACD) on early ANFH.

Methods

Forty-four (57 hips) patients with early ANFH from 2015 to 2020 were recruited for this study. They were randomized into two groups: group A received ACD, BBC, and ABR grafting; group B received treatment of ACD with β-tricalcium phosphate (β-TCP) granules and ABR grafting. The outcomes were assessed using the Harris Hip Scores (HHS) and survival rate analysis. The follow-up endpoint was defined as conversion to total hip arthroplasty (THA).

Results

Forty patients (51 hips) were ultimately included in this study for analysis. Compared with group B, patients in group A had higher postoperative function score (P = 0.032) and postoperative Harris Hip Scores (HHS) (P = 0.041). Kaplan-Meier analysis showed a trend that the survivorship of the femoral head was higher in group A than in group B.

Conclusion

The short-term follow-up results showed that the autologous bone marrow buffy coat and angioconductive bioceramic rod grafting with advanced core decompression is effective in the treatment of early ANFH.

Trial registration

Chictr.org.cn, ChiCTR2000039595. Retrospectively registered on 11 February 2015.

Multiple drilling is not effective in reducing the rate of conversion to Total hip Arthroplasty in early-stage nontraumatic osteonecrosis of the femoral head: a case-control comparative study with a natural course

BACKGROUND

To determine whether multiple drilling is effective in postponing the need for total hip arthroplasty (THA) in early-stage nontraumatic osteonecrosis of the femoral head (ONFH).

METHODS

We identified 514 patients who were diagnosed with early-stage ONFH between January 2008 and December 2018. One hundred ninety-six patients underwent multiple drilling, and 318 patients had a natural course of progression. One hundred fifty-nine patients were selected for each group after case-control matching for preoperative demographics and modified Ficat and Arlet stage. The rates of THA conversion were compared. We also performed Cox regression to identify risk factors associated with THA conversion in patients who underwent multiple drilling.

RESULTS

Kaplan-Meier survivorship with an endpoint of THA for nontraumatic reasons were not significantly different between the multiple drilling group (75.6, 95% confidence interval 67.8-83.4%) and the natural course group (72.2, 95% confidence interval 64.8-79.6%) at 5 years (log-rank, P = .191). In the Cox regression model, a larger extent of necrotic lesion, bone marrow edema (BME), and higher postoperative work intensity significantly increased the risk of THA conversion (P < .05). Among patients treated with autogenous bone grafting, there was a lower risk of failure in patients with necrotic lesion less than 15% (P < .05).

CONCLUSIONS

Multiple drilling is not effective in reducing the rate of THA conversion in early-stage nontraumatic ONFH. The risk of conversion to THA after multiple drilling is increased by a larger extent of necrotic lesion, presence of BME, and higher postoperative work intensity in patients with early-stage ONFH.

TRIAL REGISTRATION

The trial was registered in the Chinese Clinical Trial Registry ( ChiCTR2000035180 ) dated 2 August 2020.

Implantation of autologous Expanded Mesenchymal Stromal Cells in Hip Osteonecrosis through Percutaneous Forage: Evaluation of the Operative Technique

Bone forage to treat early osteonecrosis of the femoral head (ONFH) has evolved as the channel to percutaneously deliver cell therapy into the femoral head. However, its efficacy is variable and the drivers towards higher efficacy are currently unknown. The aim of this study was to evaluate the forage technique and correlate it with the efficacy to heal ONFH in a multicentric, multinational clinical trial to implant autologous mesenchymal stromal cells expanded from bone marrow (BM-hMSCs). Methods: In the context of EudraCT 2012-002010-39, patients with small and medium-sized (mean volume = 13.3%, range: 5.4 to 32.2) ONFH stage II (Ficat, ARCO, Steinberg) C1 and C2 (Japanese Investigation Committee (JIC)) were treated with percutaneous forage and implantation of 140 million BM-hMSCs in a standardized manner. Postoperative hip radiographs (AP—anteroposterior and lateral), and MRI sections (coronal and transverse) were retrospectively evaluated in 22 patients to assess the femoral head drilling orientation in both planes, and its relation to the necrotic area. Results: Treatment efficacy was similar in C1 and C2 (coronal plane) and in anterior to posterior (transverse plane) osteonecrotic lesions. The drill crossed the sclerotic rim in all cases. The forage was placed slightly valgus, at 139.3 ± 8.4 grades (range, 125.5–159.3) with higher dispersion (f = 2.6; p = 0.034) than the anatomical cervicodiaphyseal angle. Bonferroni’s correlation between both angles was 0.50 (p = 0.028). More failures were seen with a varus drill positioning, aiming at the central area of the femoral head, outside the weight-bearing area (WBA) (p = 0.049). In the transverse plane, the anterior positioning of the drill did not result in better outcomes (p = 0.477). Conclusion: The forage drilling to deliver cells should be positioned within the WBA in the coronal plane, avoiding varus positioning, and central to anterior in the transverse plane. The efficacy of delivered MSCs to regenerate bone in ONFH could be influenced by the drilling direction. Standardization of this surgical technique is desirable.

Arthroscopic assessment of concomitant intraarticular pathologies in patients with osteonecrosis of the femoral head

This study's purpose is to arthroscopically assess the occurrence of intraarticular pathologies in patients with osteonecrosis of the femoral head (OFNH) and to compare arthroscopic with radiologic findings. In a retrospective cohort analysis of ONFH patients undergoing combined core decompression (CD) and hip arthroscopy, concomitant intraarticular pathologies were qualitatively and quantitatively assessed by means of arthroscopy. Intraoperative findings were compared with preoperative radiodiagnostics. Descriptive statistics were performed with results displaying type, degree and prevalence of co-pathologies. Based on a cohort of 27 hips with ONFH at ARCO stages II and III, 26 (96.3%) presented with concomitant intraarticular findings. Cam-deformity (n = 22; 81.5%), labral defects (n = 23; 85.2%) and chondral defects (n = 20; 74.1%) were the most frequent. Four hips (14.8%) had foveal ligament anomalies. Intraoperative detection of cam-deformity positively correlated with radiologically assessed pathologic α angles (p = 0.09). Radiologic evaluation of the acetabular labrum distinctly differed from arthroscopic findings. Reliable statements concerning the cartilage status were not possible due to the great difference in quality of the magnetic resonance imaging (MRIs). The results of this study revealed an arthroscopically proven prevalence of co-pathologies in >95% of patients with ONFH. Cam-type deformity, labral anomalies and chondral defects were the most frequent. Comparison of arthroscopic and radiologic findings showed coherent results regarding cam-deformity but revealed distinct difficulties in the assessment of the labral and chondral status emphasizing the need for standardization of preoperative radiodiagnostics. Moreover, it still has to be evaluated whether combined CD and arthroscopy can improve on the overall outcomes achieved by performance of CD only.

10-year follow-up results of the prospective, double-blinded, randomized, controlled study on autologous bone marrow buffy coat grafting combined with core decompression in patients with avascular necrosis of the femoral head

Background

Avascular necrosis of the femoral head (ANFH) is a severely disabling disease of the hip. Several clinical trials have shown promising outcomes on the use of mesenchymal stem cells for the treatment of ANFH, but long-term clinical assessments are lacking. Previously, we reported the 2-year follow-up results of a prospective, double-blinded, randomized, controlled study on autologous bone marrow buffy coat grafting combined with core decompression in patients with ANFH. Here, we report the 10-year follow-up results of this study.

Methods

We recruited 43 (53 hips) patients from 2009 to 2010. The hips were randomly allocated to code decompression (CD) with or without bone marrow buffy coat (BBC) grafting. Participants underwent follow-up at 24, 60, and 120 months postoperatively. The visual analogue scale (VAS), Lequesne algofunctional index, and Western Ontario and McMaster Universities Arthritis Index (WOMAC) osteoarthritis scores were recorded. Survival rate analysis and prognostic factor analysis were performed. The endpoint was defined as progression to Ficat stage IV or conversion to hip arthroplasty.

Results

A total of 31 patients (41 hips) were included in the final analysis. The CD + BBC group had better subjective assessment scores than the CD group. The average survival times were 102.3 months and 78.1 months in the CD + BBC group and CD group, respectively (log-rank test, P = 0.029). In the univariate Cox proportional hazards regression model, age [hazard ratio (HR) = 1.079, P = 0.047] and preoperative Ficat stage (HR = 3.283, P = 0.028) indicated a high risk for progression, while the use of BBC (HR = 0.332, P = 0.042) indicated a low risk. Preoperative Ficat stage III was isolated as an independent risk factor for clinical failure in the multivariate model (HR = 3.743, P = 0.018).

Conclusion

The 10-year follow-up results of this prospective, double-blinded, randomized, controlled study showed that the use of autologous BBC in combination with core decompression was more effective than the use of core decompression alone.

Trial registration

ClinicalTrials.gov, NCT01613612. Registered on 13 December 2011—retrospectively registered

Modified technique of advanced core decompression for treatment of femoral head osteonecrosis

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a destructive condition most commonly affecting young and middle-aged patients. The leading consequence of ONFH is often a significant articular disability. Effective joint-preserving surgical treatments are urgently needed for patients with early stage ONFH when outcomes of treatment are in general better than the advanced stage disease.

AIM

To introduce a new surgery procedure called percutaneous expanded core decompression and mixed bone graft technique, which is a new way of joint-preserving surgical treatments.

METHODS

The clinical data of 6 patients with ONFH diagnosed and treated with the procedure called percutaneous expanded core decompression and mixed bone graft technique at The First Hospital of Qiqihar from March 2013 to August 2019 were retrospectively analyzed; the follow-up ended in December 2019.

RESULTS

There were 6 male patients with an average age of 43 years in our study. Gratifying results have been obtained from the comparison of Harris hip score, visual analogue scale, and imaging examination before and after operation.

CONCLUSION

This new modified technique is simple, safe, and reliable. No serious perioperative complications were observed in our cases. Advantages of the single blade expandable reamer are obvious. The adjuvant substance is inexpensive and easy to obtain. Thus, this technique is an effective joint-preserving surgical treatment for patients with early stage of ONFH.

Results of advanced core decompression in patients with osteonecrosis of the femoral head depending on age and sex-a prospective cohort study

Background

Core decompression is a common surgical technique to treat osteonecrosis of the femoral head. The aim of this study is to evaluate the effect of the parameters “age” and “sex” on the outcome of this type of treatment.

Methods

A prospective cohort study was performed. Eighty-six osteonecrotic hips with a mean follow-up of 32.5 months (± 24.8) after advanced core decompression were analysed regarding age- and sex-dependent treatment failure. Additionally, the modified Harris Hip Score and Numeric Rating Scale were compared regarding the parameters age and sex.

Results

The mean hip survival of the male participants was 51.3 months (39.4% treatment failure), whereas females presented a longer, thus not significant, mean survival of 61.4 months (30% therapy failure; p = 0.48). The further evaluation revealed significantly better survival in the patients aged < 40 years (mean survival 66.09 months, 16% treatment failure) in comparison to those aged ≥ 40 years (mean survival 50.14 months, 46% therapy failure; p = 0.03). The modified Harris Hip Score and Numeric Rating Scale results of patients whose treatment did not fail during the study period were similar, irrespective of the patient’s sex or age.

Conclusions

The study shows that the number of therapy failures is significantly higher in older patients, with 40 years of age marking the borderline. Patients’ sex does not seem to affect the outcome of treatment, and postoperative clinical scores appear to be identical with individuals not affected by therapy failure. Since age and sex are unalterable parameters, the study helps to provide valuable predictions regarding the chances of long-term hip survival after treatment of osteonecrosis.

[Modified advanced core decompression (mACD)]

OBJECTIVE

The modified advanced core decompression (mACD) combines the advantages of a low invasive core decompression with maximal removal of osteonecrotic bone and a biologic reconstruction of the resulting bone defect.

INDICATIONS

Avascular (atraumatic) osteonecrosis of the femoral head (ARCO stage II).

CONTRAINDICATIONS

Subchondral fractures (ARCO stage III); advanced osteoarthritis (e.g., ACRO stage IV); persisting risk factors such as high-dose corticoid therapy, chemotherapy, alcohol abuse; open growth plates; history of side effects or intolerance to components of the applied bone substitute; lack of patient compliance; osteomyelitis or other septic conditions.

SURGICAL TECHNIQUE

Supine positioning on the operation table, skin disinfection, and sterile draping. Skin incision and core decompression using a 3.2 mm guide wire. Removal of a bone cylinder from a nonaffected area of the femoral neck using a hollow trephine. Drilling of the osteonecrotic area over the applied wire up to 5 mm to the subchondral bone under fluoroscopy, insertion of an expandable bone knife and removal of the osteonecrotic bone supported by a curette. Bone grafting of the autologous bone into the subchondral defect zone and filling of the drill canal by resorbable bone substitute.

POSTOPERATIVE MANAGEMENT

Bed rest for 24 h, then partial weight bearing (20 kg) on crutches for 2-6 weeks depending on the bone quality in the defect zone and the applied bone substitute.

RESULTS

Midterm superiority (2 years) in hip survival of the mACD over advanced core depression and core depression, especially in ARCO stage II.

[Update of the German S3 guideline on atraumatic femoral head necrosis in adults]

The update of the German S3 guideline on atraumatic femoral head necrosis in adults aims to provide an overview of diagnosis and treatment. All clinical studies, systematic reviews, and meta-analyses published in German or English between 01.05.2013 and 30.04.2017 were included. Of 427 studies, 28 were suitable for analysis. Risk factors are corticosteroids, chemotherapy, kidney transplants, hemoglobinopathies, and alcoholism. Differential diagnoses are for example bone marrow edema, insufficiency fracture, and destructive arthropathy. Radiography should be performed upon clinical suspicion. In patients with normal radiography findings but persistent complaints, magnetic resonance imaging (ARCO classification) is the method of choice. Computed tomography (CT) can be used to confirm/exclude articular surface collapse. A subchondral sclerosis zone >30% in CT indicates a better prognosis. Left untreated, a subchondral fracture will develop within 2 years. The risk of disease development in the opposite side is high during the first 2 years, but unlikely thereafter. In conservative therapy, iloprost and alendronate can be used in a curative approach, the latter for small, primarily medial necrosis. Conservative therapy alone as well as other drug-based and physical approaches are not suitable for treatment. No particular joint-preserving surgery can currently be recommended. Core decompression should be performed in early stages with <30% necrosis. From ARCO stage IIIc or in stage IV, the indication for total hip arthroplasty should be checked. Results after total hip arthroplasty are comparable with those after coxarthrosis, although the revision rate is higher due to the relatively young age of patients. Statements on the effectiveness of cell-based therapies such as expanded stem cells or bone marrow aspirates cannot currently be made.

Prevalence of CAM deformity and its influence on therapy success in patients with osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) and CAM-type femoroacetabular impingement (FAI) present two different pathologies of the hip joint. The aim of this study is to describe the prevalence of CAM-FAI in a collective of ONFH hips and to evaluate its influence on ONFH therapy outcome. A cohort of 86 ONFH hips with a mean follow-up of 46.7 months (±20.5) after advanced core decompression (ACD) was evaluated regarding CAM deformity by measuring the alpha angle (α) and head-neck offset. The influence of CAM-type FAI was investigated using the Kaplan-Meier estimator and the Cox regression model. The mean α was 60.4° (±13.8) with 41 hips (47.7%) being ≥60°. The mean head-neck offset was 4.5 mm (±3.2), with 78 hips (90.7%) being ≤9 mm. Survival analysis indicated noticeably better ACD results for α < 60° versus α ≥ 60° (p = 0.07). Treatment failure within the first 2 years was statistically estimated as 27.7% for α < 60° versus 40.7% for α ≥ 60°: The hazard ratio for α ≥ 60° was 1.94. Head-neck offset-dependent survival showed better, though not significant, results for offset >9 mm (p = 0.38, hazard ratio 1.89 for offsets ≤9 mm). The prevalence of CAM-type deformity is greatly increased in patients with concomitant ONFH. There is a strong indication that CAM-type FAI has a negative influence on ONFH therapy outcome. The risk that ONFH treatment will fail seems to be twice as high for α ≥ 60° as for α < 60°. We recommend cotreatment of pathological head-neck offset in patients with ONFH.

Core decompression, lesion clearance and bone graft in combination with Tongluo Shenggu decoction for the treatment of osteonecrosis of the femoral head: A retrospective cohort study

The aim of this study was to evaluate the clinical effect of core decompression (CD), lesion clearance, and bone graft in combination with Tongluo Shenggu decoction for the treatment of osteonecrosis of the femoral head (ONFH).A total of 75 patients (92 hips), with ONFH at Association Research Circulation Osseous (ARCO) stages II to IIIA, were studied and divided into treatment group and control group. In control group, patients were treated with the CD in combination with autologous or artificial ceramic bone graft. In treatment group, patients were treated with the above method combined with Tongluo Shenggu decoction. Patients were followed-up at 1 month, 6 months, and 24 months after surgery. The visual analogue scale (VAS) scores, Harris Hip Score (HSS), and total effective rates were measured and recorded.The total effective rate of the treatment group was significantly higher than that of the control group (97.2% vs. 89.9%, P < .05). Compared with preoperative, the VAS and HSS scores were both improved at final follow-up, and there was significant difference between 2 groups (P < .01).The combination of CD, lesion clearance, and the bone graft with Tongluo Shenggu decoction is safe and effective for the treatment of ONFH, owing to which it can provide higher postoperative functional outcomes, reduce pain, and achieve smaller osteonecrosis area and better bone changes.

Minimally invasive treatment for osteonecrosis of the femoral head with angioconductive bioceramic rod

PURPOSE

To describe the rationale, the surgical technique, and the short-term follow-up results of a new minimally invasive treatment of osteonecrosis of the femoral head (ONFH) with an angioconductive bioceramic rod (ABR) implant.

METHODS

Sixty-two patients (72 hips) with ARCO stage IIA-IIIC ONFH treated with the minimally invasive ABR from January 2012 to December 2016 were reviewed (17 females, 45 males, mean age 44.49). This technique used the angioconductive properties of the porous implant to repair the necrosis by driving vascularization from the trochanter to the necrotic area. Patients had a mean follow-up period of 26.74 months. The outcomes were evaluated by hip joint survival, radiograph, and the Harris Hip Score (HHS). The complications occurred during the treatment period were recorded.

RESULTS

No serious post-operative complications occurred during the treatment. The overall joint survival rate was 90.27%, with seven conversions to THA. Improvements were observed in 23 (31.95%) hips, 24 (33.33%) hips remained stable, and 25 (34.72%) hips had worse results according to the radiographic evaluation. The mean HHS at the end follow-up significantly improved compared to the pre-operative mean HHS (82.27 vs 58.14, p < 0.001). In both radiographic evaluation and HHS, the treatment was more effective on patients beneath 44 years old (p < 0.05); ARCO stage II compared to stage III (p < 0.05); and China-Japan Friendship Hospital (CJFH) type C compared to CJFH type L (p < 0.05).

CONCLUSIONS

The minimally invasive treatment of ONFH with ABR showed promising results in delaying or even terminating the progression of the necrosis and improving hip function, especially in younger patients and in the early stages of the disease.

Modifications to advanced Core decompression for treatment of Avascular necrosis of the femoral head

BACKGROUND

"Advanced Core Decompression" (ACD) is a new technique for treatment of osteonecrosis of the femoral head (ONFH) that includes removal of the necrotic tissue using a percutaneous expandable reamer followed by refilling of the drill hole and the defect with an injectable, hard-setting, composite calcium sulphate (CaSO4)-calcium phosphate (CaPO4) bone graft substitute. As autologous bone has been shown to be superior to all other types of bone grafts, the aim of the study is to present and evaluate a modified technique of ACD with impaction of autologous bone derived from the femoral neck into the necrotic defect.

METHODS

A cohort of patients with an average follow-up of 30.06 months (minimum 12 months) was evaluated for potential collapse of the femoral head and any reasons that led to replacement of the operated hip. Only patients in stages 2a to 2c according to the Steinberg classification were included in the study.

RESULTS

In 75.9% the treatment was successful with no collapse of the femoral head or conversion to a total hip replacement. Analysis of the results of the different subgroups showed that the success rate was 100% for stage 2a lesions and 84.6% respectively 61.5% for stages 2b and 2c lesions.

CONCLUSIONS

Previous studies with a comparable follow-up reported less favourable results for ACD without autologous bone. Especially in stages 2b and 2c the additional use of autologous bone has a positive effect. In comparison to other hip-preserving techniques, the modified ACD technique is a very promising and minimally invasive method for treatment of ONFH.

TRIAL REGISTRATION

German clinical trials register ( DRKS00011269 , retrospectively registered).

The kinetics of remodeling of a calcium sulfate/calcium phosphate bioceramic

In the last years considerable research and development activity have been expended to find new ceramic bone substitutes for the treatment of bone defects. However in many cases the drawback of synthethic bone substitutes are the slow graft incorporation and remodelling into the host bone. The purpose of this study was to analyze the kinetics of resorption and new bone formation of new calcium sulfate (CaSO₄)/calcium phosphate (CaPO₄) bioceramic engineered to enhance its bone forming properties. We prospectively evaluated the results of a series of 15 hips with osteonecrosis of the femoral head (ONFH) treated at with core decompression and injection of the CaSO₄/CaPO₄ composite. In all hips, a quantitative computed tomography (QTC) scan was taken within one week after the surgery, at 12 months, 2 years and finally with a minimum of 4 years follow-up. The mean HU in the immediate post-operative period was 1445 (Range 1388-1602); At one year the mean HU strongly decrease at 556.6 HU (P < 0.01); The mean HU at 2 years follow-up further decreased to 475.1. The mean HU at 4 years was unchanged. The quantitative and qualitative CT scan data of this series indicates that the CaSO₄-CaPO₄ ceramic composite resorbs over a narrow timeframe and the gradual resorption of the graft within the defect provides an ideal environment for the direct new bone growth that propagates across the defect.

Operative Technique and Clinical Outcome in Endoscopic Core Decompression of Osteochondral Lesions of the Talus: A Pilot Study

BACKGROUND Revitalizing the necrotic subchondral bone and preserving the intact cartilage layer by retrograde drilling is the preferred option for treatment of undetached osteochondral lesions of the talus (OLT). We assessed the effectiveness of Endoscopic Core Decompression (ECD) in treatment of OLT. MATERIAL AND METHODS Seven patients with an undetached OLT of the medial talar dome underwent surgical treatment using an arthroscopically-guided transtalar drill meatus for core decompression of the lesion. Under endoscopic visualization the OLT was completely debrided while preserving the cartilage layer covering the defect. The drill tunnel and debrided OLT were filled using an injectable bone graft substitute. Various clinical scores, radiographic imaging, and MRI were evaluated after a mean follow-up of 24.1 months. RESULTS The American Orthopedic Foot and Ankle Society Score significantly improved from 71.0±2.4 to 90.3±5.9, and the Foot and Ankle Disability Index improved from 71.8±11.1 to 91.7±4.8. Radiographically, we observed good bone remodelling of the medial talar dome contour within 3 months. In MRI, an alteration of the bony signal of the drill tunnel and the excised OLT remained for more than 12 months. CONCLUSIONS First follow-up results for the surgical technique described in this study are highly promising for treatment of undetached stable OLT grade II or transitional stage II-III according to the Pritsch classification. Even lesions larger than 150 mm2 showed good clinical scores, with full restoration of the medial talar dome contour in radiographic imaging.

Effect of the stiffness of bone substitutes on the biomechanical behaviour of femur for core decompression

Core decompression is the most common procedure for treatment of the early stages of osteonecrosis of the femoral head. The purpose of this study was to compare the biomechanical performance of four different bone graft substitutes combined with core decompression. Subject-specific finite element models generated from computed tomography (CT) scan data were used for a comprehensive analysis. Two different contact conditions were simulated representing states of osseointegration at the interface. Our results showed that the use of a low-stiffness bone substitute did not increase the risk of femoral fracture in the early postoperative phase, but resulted in less micromotion and interfacial stresses than high-stiffness bone substitutes.

Nontraumatic Osteonecrosis of the Femoral Head: Where Do We Stand Today? A Ten-Year Update

➤ Although multiple theories have been proposed, no one pathophysiologic mechanism has been identified as the etiology for the development of osteonecrosis of the femoral head. However, the basic mechanism involves impaired circulation to a specific area that ultimately becomes necrotic.➤ A variety of nonoperative treatment regimens have been evaluated for the treatment of precollapse disease, with varying success. Prospective, multicenter, randomized trials are needed to evaluate the efficacy of these regimens in altering the natural history of the disease.➤ Joint-preserving procedures are indicated in the treatment of precollapse disease, with several studies showing successful outcomes at mid-term and long-term follow-up.➤ Studies of total joint arthroplasty, once femoral head collapse is present, have described excellent outcomes at greater than ten years of follow-up, which is a major advance and has led to a paradigm shift in treating these patients.➤ The results of hemiresurfacing and total resurfacing arthroplasty have been suboptimal, and these procedures have restricted indications in patients with osteonecrosis of the femoral head.

Geometric analysis of an expandable reamer for treatment of avascular necrosis of the femoral head

"Advanced core decompression" (ACD) is a treatment option for osteonecrosis of the femoral head (ONFH) that aims at complete removal of the necrotic tissue using a percutaneous expandable reamer and refilling of the head with an osteoconductive bone-graft substitute. The objective of this study was to evaluate if the success of ACD depends on the amount of necrotic tissue remaining after the procedure and how efficiently the necrotic tissue can be removed with the current reamer. Three-dimensional models of proximal femora including ONFH were generated from the preoperative MRIs of 50 patients who underwent ACD. Best-case removal was calculated by geometrical analysis. In 28 of 50 cases, postoperative MRI was used to determine how much necrotic tissue had been removed. Prognostic values and correlations were evaluated in order to assess success or failure of the treatment. The amount of preoperative and remaining necrosis correlates significantly with treatment failure. The larger both volumes are, the more likely it is that treatment will fail. In patients with remaining necrosis of less than 1000 mm(3), no treatment failure was observed. The amount of necrosis actually removed differed significantly from the amount calculated as the best possible result. Simulation of the removal procedure showed that complete removal is not possible. These results led to the conclusion that the success of ACD depends on the amount of necrotic tissue remaining in the femoral head after the procedure. Modifications to the instrument are necessary to increase the amount of necrotic tissue that can be removed.

Aspects of postoperative magnetic resonance imaging of patients with avascular necrosis of the femoral head, treated by advanced core decompression

OBJECTIVE

To analyze remodeling processes after advanced core decompression (ACD) in patients with avascular femoral head necrosis by means of 3T MRI and to identify indicators for clinical outcome considering the defect size and characteristics of the bone graft and of the neighboring regeneration tissue.

MATERIALS AND METHODS

Thirty-four hips, with preexisting preoperative MRIs in 21 cases, were examined 1-34 months (mean 12.7) postoperatively by 3T MRI. The volume of necrosis was measured manually pre- and postoperatively to calculate absolute as well as percentage necrosis reduction. The signal intensity of the bone graft was quantified using a 4-point scale. Border phenomena between the bone graft and bone were described and classified into groups. Wilcoxon sign-rank test was used to identify correlations between the analyzed items and clinical signs of femoral head collapse after a mean follow-up time of 28.6 months (10.4-46.8).

RESULTS

Mean percentage reduction of necrosis was significantly higher in asymptomatic patients (59.36%) compared to patients with signs of femoral head collapse (28.78%, p = 0.008). Signal intensity of the bone graft increased in T1w and T2w TIRM sequences over time after surgery and was significantly higher in asymptomatic patients. Five border phenomena between the bone graft and healthy bone were identified. Among them, the so-called "rail sign" representing three layers of remodeling tissue correlated with the histological observations.

CONCLUSION

A variety of border phenomena representing remodeling processes have been described using 3T MRI. Beneath the percentage amount of necrosis reduction, we identified the signal intensity of the bone graft as an indicator for clinical outcome.

Two-year follow-up after advanced core decompression

The so-called "Advanced Core Decompression" (ACD) is a new option that tries to remove the necrotic tissue in patients with osteonecrosis of the femoral head (AVN) in a minimally invasive way by the use of a percutaneous expandable reamer and refilling with a resorbable and osteoinductive bone-graft substitute. Seventy-two hips of sixty patients with a mean follow-up of 29.14 months after ACD have been included in this study. Patients underwent physical examination preoperatively and six weeks after surgery as well as at two further follow-ups. Certain phases in disease progression and size of the necrotic lesion were differentiated on the basis of the classification of osteonecrosis of the femoral head by Steinberg.The femoral heads had collapsed in 24 cases (33%). Analysis of the survival rates with regard to defect size revealed that the largest defects had a significantly higher rate of femoral head collapse than the smaller defects. Clinical scores were also depending on defect size but also on disease stage. The current ACD technique has not yet achieved any significant improvement in the success rate of core decompression procedures. It can be concluded that the success of ACD depends especially on the defect size. Copyright © 2015 John Wiley & Sons, Ltd.

Hip imaging of avascular necrosis at 7 Tesla compared with 3 Tesla

OBJECTIVES

To compare ultra-high field, high-resolution bilateral magnetic resonance imaging (MRI) of the hips at 7 Tesla (T) with 3 T MRI in patients with avascular necrosis (AVN) of the femoral head by subjective image evaluations, contrast measurements, and evaluation of the appearance of imaging abnormalities.

MATERIALS AND METHODS

Thirteen subjects with avascular necrosis treated using advanced core decompression underwent MRI at both 7 T and 3 T. Sequence parameters as well as resolution were kept identical for both field strengths. All MR images (MEDIC, DESS, PD/T2w TSE, T1w TSE, and STIR) were evaluated by two radiologists with regard to subjective image quality, soft tissue contrasts, B1 homogeneity (four-point scale, higher values indicating better image quality) and depiction of imaging abnormalities of the femoral heads (three-point scale, higher values indicating the superiority of 7 T). Contrast ratios of soft tissues were calculated and compared with subjective data.

RESULTS

7-T imaging of the femoral joints, as well as 3-T imaging, achieved "good" to "very good" quality in all sequences. 7 T showed significantly higher soft tissue contrasts for T2w and MEDIC compared with 3 T (cartilage/fluid: 2.9 vs 2.2 and 3.6 vs 2.6), better detailed resolution for cartilage defects (PDw, T2w, T1w, MEDIC, DESS > 2.5) and better visibility of joint effusions (MEDIC 2.6; PDw/T2w 2.4; DESS 2.2). Image homogeneity compared with 3 T (3.9-4.0 for all sequences) was degraded, especially in TSE sequences at 7 T through signal variations (7 T: 2.1-2.9); to a lesser extent also GRE sequences (7 T: 2.9-3.5). Imaging findings related to untreated or treated AVN were better delineated at 3 T (≤1.8), while joint effusions (2.2-2.6) and cartilage defects (2.5-3.0) were better visualized at 7 T. STIR performed much more poorly at 7 T, generating large contrast variations (1.5).

CONCLUSIONS

7-T hip MRI showed comparable results in hip joint imaging compared with 3 T with slight advantages in contrast detail (cartilage defects) and fluid detection at 7 T when accepting image degradation medially.