Outcome after a new porous tantalum rod implantation for treatment of early-stage femoral head osteonecrosis

Progress of research on the surface functionalization of tantalum and porous tantalum in bone tissue engineering

Tantalum and porous tantalum are ideal materials for making orthopedic implants due to their stable chemical properties and excellent biocompatibility. However, their utilization is still affected by loosening, infection, and peripheral inflammatory reactions, which sometimes ultimately lead to implant removal. An ideal bone implant should have exceptional biological activity, which can improve the surrounding biological microenvironment to enhance bone repair. Recent advances in surface functionalization have produced various strategies for developing compatibility between either of the two materials and their respective microenvironments. This review provides a systematic overview of state-of-the-art strategies for conferring biological functions to tantalum and porous tantalum implants. Furthermore, the review describes methods for preparing active surfaces and different bioactive substances that are used, summarizing their functions. Finally, this review discusses current challenges in the development of optimal bone implant materials.

Preparation, modification, and clinical application of porous tantalum scaffolds

Porous tantalum (Ta) implants have been developed and clinically applied as high-quality implant biomaterials in the orthopedics field because of their excellent corrosion resistance, biocompatibility, osteointegration, and bone conductivity. Porous Ta allows fine bone ingrowth and new bone formation through the inner space because of its high porosity and interconnected pore structure. It contributes to rapid bone integration and long-term stability of osseointegrated implants. Porous Ta has excellent wetting properties and high surface energy, which facilitate the adhesion, proliferation, and mineralization of osteoblasts. Moreover, porous Ta is superior to classical metallic materials in avoiding the stress shielding effect, minimizing the loss of marginal bone, and improving primary stability because of its low elastic modulus and high friction coefficient. Accordingly, the excellent biological and mechanical properties of porous Ta are primarily responsible for its rising clinical translation trend. Over the past 2 decades, advanced fabrication strategies such as emerging manufacturing technologies, surface modification techniques, and patient-oriented designs have remarkably influenced the microstructural characteristic, bioactive performance, and clinical indications of porous Ta scaffolds. The present review offers an overview of the fabrication methods, modification techniques, and orthopedic applications of porous Ta implants.

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.

FEMORAL HEAD DECOMPRESSION AND GRAFT: TECHNIQUE WITH NEW INSTRUMENTS

INTRODUCTION

Osteonecrosis of the femoral head (ONFH) is a pathology that can be treated with many approaches by the hip surgeon. Advanced decompression is a technique that aims to prevent the collapse of the femoral head and the arthrosis process of the joint, a technique already widespread and used by hip surgeons. In this study, we performed the technique with a new retractable blade and a new bone substitute as graft for the femoral head.

OBJECTIVE

To evaluate the technique with new instruments (EasyCore Hip^®) and a calcium phosphate bone substitute (Graftys^® HBS).

METHODS

Patients with osteonecrosis of the femoral head without major degenerative changes, such as femoral head collapse, were selected. Femoral head decompression was performed using the EasyCore Hip^® retractable blade along with the calcium phosphate bone substitute as graft (Graftys^® HBS).

RESULTS

The instruments proved to be reliable and reproducible, and the bone substitute presented good mechanical resistance, maintaining its temperature during the surgery. The disposable retractable blade presents variation in size and angle, which is an advantage in the removal of necrotic bone. However, we must take some precautions in order to achieve a better result.

CONCLUSION

using EasyCore Hip^® instruments and a calcium phosphate bone substitute (Graftys^® HBS) is safe; however, some precautions must be taken during the use of the technique. Level of Evidence IV, Case Series.

Influence of porous tantalum scaffold pore size on osteogenesis and osteointegration: A comprehensive study based on 3D-printing technology

The emerging role of porous tantalum (Ta) scaffold for bone tissue engineering is noticed due to its outstanding biological properties. However, it is controversial which pore size and porosity are more conducive for bone defect repair. In the present work, porous tantalum scaffolds with pore sizes of 100-200, 200-400, 400-600 and 600-800 μm and corresponding porosities of 25%, 55%, 75%, and 85% were constructed, using computer aided design and 3D printing technologies, then comprehensively studied by in vitro and in vivo studies. We found that Ta scaffold with pore size of 400-600 μm showed stronger ability in facilitating cell adhesion, proliferation, and osteogenic differentiation in vitro. In vivo tests identified that porous tantalum scaffolds with pore size of 400-600 μm showed better performance of bone ingrowth and integration. In mechanism, computational fluid dynamics analysis proved porous tantalum scaffolds with pore size of 400-600 μm hold appropriate permeability and surface area, which facilitated cell adhesion and proliferation. Our results strongly indicate that pore size and porosity are essential for further applications of porous tantalum scaffolds, and porous tantalum scaffolds with pore size 400-600 μm are conducive to osteogenesis and osseointegration. These findings provide new evidence for further application of porous tantalum scaffolds for bone defect repair.

Failure and progression to total hip arthroplasty among the treatments for femoral head osteonecrosis: a Bayesian network meta-analysis

INTRODUCTION

Osteonecrosis of the femoral head (ONFH) often leads to secondary osteoarthritis and total hip arthroplasty.

SOURCE OF DATA

Recent published literatures.

AREAS OF AGREEMENT

There has been increasing focus on the early intervention in ONFH patients to preserve the native hip articulation, reduce pain and improve function.

AREAS OF CONTROVERSY

Efficacy of surgical strategies for ONFH is debated. Several clinical studies showed controversial results, and the best treatment has not yet been clarified.

GROWING POINTS

To provide an overview over current treatment options for ONFH compares their failure rates and conversion to total hip arthroplasty (THA) rates.

AREAS TIMELY FOR DEVELOPING RESEARCH

Core decompression (CD) augmented with autologous bone grafting plus the implantation of bone marrow concentrate can decrease the rate of failure and progression to THA rates compared to CD alone.

Outcome of tantalum rod insertion in the treatment of osteonecrosis of the femoral head with minimum follow-up of 1 year: a meta-analysis and systematic review

Osteonecrosis of the femoral head (ONFH) is a debilitating disease that can cause deformity and collapse of the femoral head, thus leading to the development of degenerative joint disease that can incapacitate the patient with pain and reduction in hip mobility. This study aims to determine the safety and efficacy of tantalum rod insertion in the treatment of ONFH with a minimum follow-up period of 1 year. A multi-database search was performed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Data from studies assessing the clinical and radiological outcomes as well as complications of tantalum rod insertion in the treatment of ONFH with a minimum follow-up period of 1 year were extracted and analyzed. Ten studies were included in this meta-analysis, consisting of 550 hips. There was a statistically significant increase in HHS (MD = 30.35, 95% CI: 20.60-40.10, P < 0.001) at final follow-up versus pre-operative scores. The weighted pooled proportion (PP) of radiographic progression of ONFH was 0.221 (95% CI: 0.148-0.316), while that of progression into femoral head collapse was 0.102 (95% CI: 0.062-0.162). Conversion to total hip arthroplasty (THA) had a PP of 0.158 (95% CI: 0.107-0.227) with a mean weighted period of 32.4 months (95% CI: 24.9-39.9 months). Subgroup analysis of conversion to THA when tantalum rods were used in conjunction with bone grafting (PP = 0.150, 95% CI: 0.092-0.235) showed a marginal risk reduction than when compared with subgroup analysis of tantalum rods being used alone (PP = 0.154, 95% CI: 0.078-0.282). Tantalum rod is a safe alternative option to the current joint-preserving procedures available in the treatment of ONFH. However, more studies are needed to investigate and identify the most appropriate patients who would benefit most and the synergistic effect brought on by the use of complementary biological augmentation of bone grafting or stem cells with tantalum rods.