Invasive electromagnetic field treatment in osteonecrosis of the femoral head: a prospective cohort study

The Effect of Doping on the Electrical and Dielectric Properties of Hydroxyapatite for Medical Applications: From Powders to Thin Films

Recently, the favorable electrical properties of biomaterials have been acknowledged as crucial for various medical applications, including both bone healing and growth processes. This review will specifically concentrate on calcium phosphate (CaP)-based bioceramics, with a notable emphasis on hydroxyapatite (HA), among the diverse range of synthetic biomaterials. HA is currently the subject of extensive research in the medical field, particularly in dentistry and orthopedics. The existing literature encompasses numerous studies exploring the physical-chemical, mechanical, and biological properties of HA-based materials produced in various forms (i.e., powders, pellets, and/or thin films) using various physical and chemical vapor deposition techniques. In comparison, there is a relative scarcity of research on the electrical and dielectric properties of HA, which have been demonstrated to be essential for understanding dipole polarization and surface charge. It is noteworthy that these electrical and dielectric properties also offer valuable insights into the structure and functioning of biological tissues and cells. In this respect, electrical impedance studies on living tissues have been performed to assess the condition of cell membranes and estimate cell shape and size. The need to fill the gap and correlate the physical-chemical, mechanical, and biological characteristics with the electrical and dielectric properties could represent a step forward in providing new avenues for the development of the next-generation of high-performance HA-doped biomaterials for future top medical applications. Therefore, this review focuses on the electrical and dielectric properties of HA-based biomaterials, covering a range from powders and pellets to thin films, with a particular emphasis on the impact of the various dopants used. Therefore, it will be revealed that each dopant possesses unique properties capable of enhancing the overall characteristics of the produced structures. Considering that the electrical and dielectric properties of HA-based biomaterials have not been extensively explored thus far, the aim of this review is to compile and thoroughly discuss the latest research findings in the field, with special attention given to biomedical applications.

Invasive electrical stimulation in the treatment of avascular osteonecrosis of the femoral head - mid-term results

The study aimed to evaluate the outcomes of osteonecrosis of the femoral head (ONFH) in adults after surgical treatment including invasive electromagnetic osteostimulation (E-Stim). Further, the influence of disease stage and several comorbidities on the joint preservation rate should be examined. Sixty patients (66 hip joints) with ONFH were included in this retrospective cross-sectional analysis (mean follow-up: 58 months, 19-110 months). Potential ONFH risk factors and comorbidities (ONFH stage, age, sex, alcohol, smoking, cortisone medication, chemotherapy) were recorded. The influence of specific parameters on the joint preservation rates was evaluated by a multivariate logistic regression analysis. Finally, patients with preserved hip joints underwent an assessment of their last available X-rays. The joint preservation rate depended on the initial ONFH Steinberg stage (I+II: 82.8%, III: 70.8%, ≥ IVa: 38.5%). Initially collapsed ONFH (p ≤ 0.001) and cortisone therapy (p = 0.004) significantly decreased the joint preservation rates. In case of progressed ONFH, the presence of ≥ 2 risk factors resulted in higher THA conversion rates (stage III: OR 18.8; stage ≥IVa: OR 12). In 94% of the available X-rays, the ONFH stage improved or did not progress. No complications could be attributed to the E-Stim device or procedure. The present surgical protocol including minimally invasive E-Stim revealed high joint preservation rates for non-collapsed ONFH after mid-term postoperative follow-up. Especially in progressed ONFH, the-risk profile seems to be crucial and hence, for joint preserving surgery, careful patient selection is recommended.

Core decompression vs. allogenic non-vascularized bone grafting in patients with osteonecrosis of the femoral head

Background

Core decompression and allogenic non-vascularized bone grafting are used in the early stage of osteonecrosis of the femoral head for a period. Since the comparison of the core decompression and allogenic non-vascularized bone grafting are less reported, the purpose of our study was to investigate the difference of two procedures in patients with the osteonecrosis of the femoral head.

Methods

Between January 2018 and January 2019, 59 patients (64 hips) were divided into core decompression group and non-vascularized bone grafting group according to their procedures. The primary outcomes are visual analog score (VAS) and Harris hip score. Survivorship was analyzed with the collapse of the femoral head or conversion to total hip arthroplasty (THA) as the endpoint.

Results

At the final follow-up, two hips underwent THA in the core decompression group and three hips in the allogenic non-vascularized bone grafting group. The radiographic survival rates were 76.9% and 77.3%, respectively, in both groups. The VAS of the core decompression group was 6.08 ± 1.164 and 3.30 ± 1.431 before and 2 years after operation (P < 0.05), respectively. The VAS of the allogenic non-vascularized bone grafting group was 6.00 ± 1.209 and 3.15 ± 1.537 before and 2 years after operation (P < 0.05), respectively. The Harris hip score of the core decompression group was 52.49 ± 6.496 before operation, and 2 years after operation, it increased by 81.14 ± 8.548 (P < 0.05); The Harris hip score of allogenic the non-vascularized bone grafting group was 53.56 ± 5.925 and 81.33 ± 7.243 before and 2 years after operation (P < 0.05), respectively. In the core decompression group, body mass index (BMI) >25 kg/m2 was correlated with the collapse of femoral head or conversion to THA [P < 0.05; 95% confidence interval (CI), 0.006-1.334], and Association Research Circulation Osseous (ARCO) III was correlated with the collapse of femoral head or conversion to THA (P < 0.05; 95% CI, 2.514-809.650). In the allogenic non-vascularized bone grafting group, age, BMI, and ARCO stage were significantly associated with the collapse of femoral head or conversion to THA (P > 0.05).

Conclusion

The clinical survival rate of the femoral head in the core decompression group was slightly better than that in the allogenic non-vascularized bone grafting group. There was no significant difference in the radiographic survival rate of the femoral head between the two groups. Both groups can alleviate pain and improve functional of patients, but there was no significant difference in the degree of improvement. In the core decompression group, BMI >25 kg/m2 and ARCO III correlated with the collapse of femoral head or conversion to THA. In the allogenic non-vascularized bone grafting group, no association was found between age, BMI, and ARCO stage and the collapse of femoral head or conversion to THA.

Level of evidence

III.

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.

Etiology of Femoral Head Avascular Necrosis in Patients: A Cross-Sectional Study

Background

Avascular necrosis (AVN), known as osteonecrosis, aseptic necrosis, or ischemic bone necrosis, results in the destruction of bone cells. In the present study, we aimed to report the most common causes of AVN in in patients referred to Isfahan educational and medical centers.

Materials and Methods

This study is a cross-sectional study that was performed on all patients with AVN in medical educational centers in Isfahan during 2019 and 2020. We included all patients diagnosed with AVN. Patients' information including age, sex, cause of femoral head necrosis, medical history, and drug usage were collected. Finally, reliable data from 99 patients were recorded.

Results

We collected data of 99 patients in this study. The most prevalent cause of ANV was corticosteroids use (32.3%), and it was more prevalent among women (51.4%); the second prevalent cause of AVN in our study sample was trauma (28.28%), and it was more prevalent among men (32.8%).

Conclusion

The most common cause of AVN was corticosteroids, which was consistent with previous studies. Other main causes of AVN were traumatic or idiopathic issues.

Performance of a Piezoelectric Energy Harvesting System for an Energy-Autonomous Instrumented Total Hip Replacement: Experimental and Numerical Evaluation

Instrumented implants can improve the clinical outcome of total hip replacements (THRs). To overcome the drawbacks of external energy supply and batteries, energy harvesting is a promising approach to power energy-autonomous implants. Therefore, we recently presented a new piezoelectric-based energy harvesting concept for THRs. In this study, the performance of the proposed energy harvesting system was numerically and experimentally investigated. First, we numerically reproduced our previous results for the physiologically based loading situation in a simplified setup. Thereafter, this configuration was experimentally realised by the implantation of a functional model of the energy harvesting concept into an artificial bone segment. Additionally, the piezoelectric element alone was investigated to analyse the predictive power of the numerical model. We measured the generated voltage for a load profile for walking and calculated the power output. The maximum power for the directly loaded piezoelectric element and the functional model were 28.6 and 10.2 µW, respectively. Numerically, 72.7 µW was calculated. The curve progressions were qualitatively in good accordance with the numerical data. The deviations were explained by sensitivity analysis and model simplifications, e.g., material data or lower acting force levels by malalignment and differences between virtual and experimental implantation. The findings verify the feasibility of the proposed energy harvesting concept and form the basis for design optimisations with increased power output.

Vascularized Greater Trochanter Bone Flap Transfer for Treatment of ARCO Stage-IIB to IIIB Osteonecrosis of the Femoral Head

Background

The goal of a vascularized bone flap transfer is to replace the necrotic bone of the femoral head, restore the blood supply, and provide new bone and mechanical support for the femoral head.

Description

The major steps of the procedure that are demonstrated in this article are: (1) using the anterolateral approach to the hip, the incision is made; (2) the interval between the rectus femoris and vastus lateralis is split, the transverse branch of the lateral femoral circumflex artery is identified, and the pedicle is isolated and protected; (3) the vascularized bone flap is harvested from the greater trochanter; (4) necrotic bone is debrided through a bone window made at the junction of the femoral neck and head; (5) the cancellous bone from the greater trochanter is implanted, and the vascularized bone flap is positioned and fixed; and (6) the wound is closed in layers. Complications are rare, and full weight-bearing is allowed after 3 months postoperatively.

Alternatives

Free vascularized fibular graft.

Rationale

Compared with a free vascularized fibular grafting technique, vascularized bone-grafting of the greater trochanter has the advantages of being less invasive, incurring lower donor-site morbidity, and not requiring any microsurgical technique because there is no vascular anastomosis.

Vascularized Iliac Bone Flap Transfer for Early and Middle Stages of Osteonecrosis of the Femoral Head

Background

Osteonecrosis of the femoral head often affects young active adults and leads to destruction of the hip joint and severe arthritis^1-4. Despite improvements in hip arthroplasty design and techniques, it is unlikely that prosthetic replacements will endure for life. Alternatively, various head-preserving procedures have been used to avert or delay the need for a total hip arthroplasty^5-11. Vascularized iliac bone flap transfer is a joint-preserving procedure that can be considered for younger patients with early or middle-stage osteonecrosis of the femoral head.

Description

The major steps of the procedure include (1) an anterior approach to the affected hip, (2) creation of a bone flap from the iliac crest pedicled with the ascending branch of the lateral circumflex femoral artery, (3) obtaining cancellous bone from the iliac crest, (4) exposure of the anterior aspect of the femoral neck, (5) creation of a 2 × 2-cm window at the junction of the femoral head and neck, (6) debridement and removal of the necrotic bone, (7) implantation of the cancellous bone and vascularized bone flap, (8) fixation of the bone flap, and (9) layer-by-layer wound closure. Complications are rare, and full weight-bearing is allowed at 6 months postoperatively.

Alternatives

Alternatives to the procedure include core decompression, nonvascularized bone-grafting, free vascularized fibular grafting, and vascularized greater trochanter grafting.

Rationale

Various femoral head-preserving procedures have been reported. Core decompression is an effective femoral head-preserving procedure and is recommended as the first surgical treatment option for symptomatic small to medium-sized precollapse lesions. However, outcomes are poor when a patient has a large lesion or femoral head collapse. The advantage of vascularized iliac bone flap transfer is that it allows femoral head decompression, restores blood supply, and provides structural support. Thus, this procedure can be performed in patients with later osteonecrosis stages before hip osteoarthritis has progressed.

Effect of electric stimulation on human chondrocytes and mesenchymal stem cells under normoxia and hypoxia

During joint movement and mechanical loading, electric potentials occur within cartilage tissue guiding cell development and regeneration. Exposure of cartilage exogenous electric stimulation (ES) may imitate these endogenous electric fields and promote healing processes. Therefore, the present study investigated the influence of electric fields on human chondrocytes, mesenchymal stem cells and the co-culture of the two. Human chondrocytes isolated from articular cartilage obtained post-mortally and human mesenchymal stem cells derived from bone marrow (BM-MSCs) were seeded onto a collagen-based scaffold separately or as co-culture. Following incubation with the growth factors over 3 days, ES was performed using titanium electrodes applying an alternating electric field (700 mV, 1 kHz). Cells were exposed to an electric field over 7 days under either hypoxic or normoxic culture conditions. Following this, metabolic activity was investigated and synthesis rates of extracellular matrix proteins were analyzed. ES did not influence metabolic activity of chondrocytes or BM-MSCs. Gene expression analyses demonstrated that ES increased the expression of collagen type II mRNA and aggrecan mRNA in human chondrocytes under hypoxic culture conditions. Likewise, collagen type II synthesis was significantly increased following exposure to electric fields under hypoxia. BM-MSCs and the co-culture of chondrocytes and BM-MSCs revealed a similar though weaker response regarding the expression of cartilage matrix proteins. The electrode setup may be a valuable tool to investigate the influence of ES on human chondrocytes and BM-MSCs contributing to fundamental knowledge including future applications of ES in cartilage repair.

An evidence-based guide to the treatment of osteonecrosis of the femoral head

Non-traumatic osteonecrosis of the femoral head is a potentially devastating condition, the prevalence of which is increasing. Many joint-preserving forms of treatment, both medical and surgical, have been developed in an attempt to slow or reverse its progression, as it usually affects young patients. However, it is important to evaluate the best evidence that is available for the many forms of treatment considering the variation in the demographics of the patients, the methodology and the outcomes in the studies that have been published, so that it can be used effectively. The purpose of this review, therefore, was to provide an up-to-date, evidence-based guide to the management, both non-operative and operative, of non-traumatic osteonecrosis of the femoral head. Cite this article: Bone Joint J 2017;99-B:1267-79.

The role of electrical stimulation in the management of avascular necrosis of the femoral head in adults: a systematic review

BACKGROUND

Avascular necrosis of the femoral head causes significant morbidity and occurs in up to 20,000 people per year. A variety of nonoperative and operative measures have been trialled however a definitive treatment algorithm is yet to be established. Young adults in many cases have undergone multiple surgical procedures in their lifetime with increasing risks of complications. Less invasive techniques may help reduce the number of operations required and positively influence the natural history of the disease process. Our aim was to navigate the literature and examine the results of electrical stimulation of the femoral head in avascular necrosis.

METHODS

The following defined search strategy was used to perform a systematic review using MEDLINE and Google Scholar databases: ((avascular necrosis) OR (osteonecrosis)) AND (femoral head) AND ((electrical stimulation) OR (capacitive coupling) OR (pulsed electromagnetic fields)). Articles were reviewed and data compiled into tables for analysis.

RESULTS

Fourty six articles were identified with a total of 10 articles meeting the inclusion criteria. 8 articles were prospective studies and 2 were retrospective. Early Ficat stages showed the best responses to treatment via pulsed electromagnetic fields with improvements in both clinical and radiographic parameters. Direct current and capacitative coupling have had a more ambiguous outcome.

CONCLUSIONS

Pulsed electromagnetic fields may have a role in the management of early avascular necrosis. The paucity of clinical studies into this technique indicates a need for further studies.

PTH[1-34] improves the effects of core decompression in early-stage steroid-associated osteonecrosis model by enhancing bone repair and revascularization

Steroid-associated osteonecrosis (SAON) might induce bone collapse and subsequently lead to joint arthroplasty. Core decompression (CD) is regarded as an effective therapy for early-stage SAON, but the prognosis is unsatisfactory due to incomplete bone repair. Parathyroid hormone[1–34] (PTH[1–34]) has demonstrated positive efficacy in promoting bone formation. We therefore evaluated the effects of PTH on improving the effects of CD in Early-Stage SAON. Distal femoral CD was performed two weeks after osteonecrosis induction or vehicle injection, with ten of the ON-induced rabbits being subjected to six-week PTH[1–34] treatment and the others, including ON-induced and non-induced rabbits, being treated with vehicle. MRI confirmed that intermittent PTH administration improved SAON after CD therapy. Micro-CT showed increased bone formation within the tunnel. Bone repair was enhanced with decreased empty osteocyte lacunae and necrosis foci area, resulting in enhanced peak load and stiffness of the tunnel. Additionally, PTH enlarged the mean diameter of vessels in the marrow and increased the number of vessels within the tunnels, as well as elevated the expression of BMP-2, RUNX2, IGF-1, bFGF and VEGF, together with serum OCN and VEGF levels. Therefore, PTH[1–34] enhances the efficacy of CD on osteogenesis and neovascularization, thus promoting bone and blood vessels repair in the SAON model.

A Novel In Vitro System for Comparative Analyses of Bone Cells and Bacteria under Electrical Stimulation

Electrical stimulation is a promising approach to enhance bone regeneration while having potential to inhibit bacterial growth. To investigate effects of alternating electric field stimulation on both human osteoblasts and bacteria, a novel in vitro system was designed. Electric field distribution was simulated numerically and proved by experimental validation. Cells were stimulated on Ti6Al4V electrodes and in short distance to electrodes. Bacterial growth was enumerated in supernatant and on the electrode surface and biofilm formation was quantified. Electrical stimulation modulated gene expression of osteoblastic differentiation markers in a voltage-dependent manner, resulting in significantly enhanced osteocalcin mRNA synthesis rate on electrodes after stimulation with 1.4V_RMS. While collagen type I synthesis increased when stimulated with 0.2V_RMS, it decreased after stimulation with 1.4V_RMS. Only slight and infrequent influence on bacterial growth was observed following stimulations with 0.2V_RMS and 1.4V_RMS after 48 and 72 h, respectively. In summary this novel test system is applicable for extended in vitro studies concerning definition of appropriate stimulation parameters for bone cell growth and differentiation, bacterial growth suppression, and investigation of general effects of electrical stimulation.

Core decompression versus other joint preserving treatments for osteonecrosis of the femoral head: a meta-analysis

INTRODUCTION

Osteonecrosis of femoral head (ONFH) leads to hip osteoarthritis (HOA); among joint preserving treatments (JPT), the role of core decompression (CD) is still debated. We assessed the efficacy of CD compared with all other JPT in delaying the natural osteonecrosis evolution to HOA.

SOURCES OF DATA

Following the PRISMA checklist, the Medline and Scopus databases were searched. Fifteen- to 70-year-old subjects with ONFH with a minimum follow-up of 24 months were considered. The outcomes evaluated were patient clinical status, radiographic progression and total hip arthroplasty (THA) or further surgery (FS) need. Risk ratio (RR) was calculated for every outcome reported. RCT, CCT and prospective studies were included.

AREAS OF AGREEMENT

A total of 12 studies (776 patients) met the inclusion criteria. Clinical outcome (RR = 1.14; 95% CI 0.58-2.32; P = 0.05), radiographic progression (RR = 1.64; 95% CI 1.14-2.35; P = 0.05) and the need for THA/FS (RR = 1.52; 95% CI 0.95-2.45; P = 0.05) suggested a slight superiority of other JPT compared with CD.

AREAS OF CONTROVERSY

High heterogeneity of the primary investigations was the main limitation of our study.

GROWING POINTS

The efficacy and effectiveness of core decompression for ONFH are, at best, no better than other joint preserving strategies. The more recent scientific evidence seems to suggest that such procedure is less successful than other joint preserving strategies.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further studies are needed to identify the best therapeutic approach to the ONFH.

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.

A current review of non-vascularized bone grafting in osteonecrosis of the femoral head

Over the past three decades, non-vascularized bone grafts have been demonstrated to be viable treatments for pre- and early post-collapse osteonecrosis of the femoral head; however, there are limited reviews on this topic. Therefore, the purposes of this review are to (1) provide a summary of the different surgical techniques and their respective clinical outcomes and (2) evaluate new adjunct therapies. Originally, non-vascularized bone grafting was performed using the Phemister technique with varying results. More recently, newer techniques such as the lightbulb and trapdoor are used to place non-vascularized bone grafts with excellent results. The addition of various biological agents has demonstrated positive results; however, further studies are needed to confirm the best appropriate indications and to elucidate long-term results.

Midterm results of treating femoral head osteonecrosis with autogenous corticocancellous bone grafting

BACKGROUND

Appropriate treatment of osteonecrosis of femoral head (ONFH) remains challenging.

OBJECTIVES

Here, we report the results of treating these patients with auto-corticocancellous bone graft from iliac crest to overcome the need for early total hip arthroplasty (THA).

PATIENTS AND METHODS

There were 132 hips (96 patients) with ONFH. Association Research Circulation Osseous (ARCO) type II and III underwent auto-corticocancellous bone grafting from the iliac crest in the current prospective study. Before the operation and in the final postoperative visit, the pain intensity using visual analogue scale (VAS), range of hip motions and Harris hip score (HHS) were determined and compared. Patients were followed for 48.5 ± 17.9 months.

RESULTS

The shape of head and the joint space were preserved in 120 hips (90.9%). There were 12 hips in which the disease progressed to grade IV and resulted in THA in 10 of them. The pain intensity significantly decreased (6.3 ± 4.1 vs. 1.4 ± 2) and HHS (35.8 ± 15.3 vs. 79.5 ± 16.2) and range of motion (ROM) significantly improved after the operation (P < 0.001).

CONCLUSIONS

Necrotic bone removal and filling the femoral head cavity with auto-corticocancellous bone graft from iliac crest is an effective femoral head preserving method in treating patients with precollapse stages of ONFH and preventing the need for early THA, especially in young active populations.