Novel 3D printed integral customized acetabular prosthesis for anatomical rotation center restoration in hip arthroplasty for developmental dysplasia of the hip crowe type III: A Case Report

Biomechanical analysis and clinical observation of 3D-printed acetabular prosthesis for the acetabular reconstruction of total hip arthroplasty in Crowe III hip dysplasia

Objective: This study aimed to evaluate the biomechanical effectiveness of 3D-printed integrated acetabular prosthesis (IAP) and modular acetabular prosthesis (MAP) in reconstructing the acetabulum for patients with Crowe III developmental dysplasia of the hip (DDH). The results of this study can provide a theoretical foundation for the treatment of Crowe III DDH in total hip arthroplasty (THA). Methods: Finite element (FE) analysis models were created to reconstruct Crowe III DDH acetabular defects using IAP and MAP. The contact stress and relative micromotion between the acetabular prosthesis and the host bone were analyzed by gradually loading in three increments (210 N, 2100 N, and 4200 N). In addition, five patients with Crowe III DDH who underwent IAP acetabular reconstruction were observed. Results: At the same load, the peak values of IAP contact stress and relative micromotion were lower than those of MAP acetabular reconstruction. Under jogging load, the MAP metal augment's peak stress exceeded porous tantalum yield strength, and the risk of prosthesis fracture was higher. The peak stress in the bone interface in contact with the MAP during walking and jogging was higher than that in the cancellous bone, while that of IAP was higher than that of the cancellous bone only under jogging load, so the risk of MAP cancellous bone failure was greater. Under jogging load, the relative micromotion of the MAP reconstruction acetabular implant was 45.2 μm, which was not conducive to bone growth, while under three different loads, the relative micromotion of the IAP acetabular implant was 1.5-11.2 μm, all <40 μm, which was beneficial to bone growth. Five patients with IAP acetabular reconstruction were followed up for 11.8 ± 3.4 months, and the Harris score of the last follow-up was 85.4 ± 5.5. The imaging results showed good stability of all prostheses with no adverse conditions observed. Conclusion: Compared with acetabular reconstruction with MAP, IAP has a lower risk of loosening and fracture, as well as a better long-term stability. The application of IAP is an ideal acetabular reconstruction method for Crowe III DDH.

A systematic review of follow-up results of additively manufactured customized implants for the pelvic area

INTRODUCTION

While 3D printing of bone models for preoperative planning or customized surgical templating has been successfully implemented, the use of patient-specific additively manufactured (AM) implants is a newer application not yet well established. To fully evaluate the advantages and shortcomings of such implants, their follow-up results need to be evaluated.

AREA COVERED

This systematic review provides a survey of the reported follow-ups on AM implants used for oncologic reconstruction, total hip arthroplasty both primary and revision, acetabular fracture, and sacrum defects.

EXPERT OPINION

The review shows that Titanium alloy (Ti4AL6V) is the most common type of material system used due to its excellent biomechanical properties. Electron beam melting (EBM) is the predominant AM process for manufacturing implants. In almost all cases, porosity at the contact surface is implemented through the design of lattice or porous structures to enhance osseointegration. The follow-up evaluations show promising results, with only a small number of patients suffering from aseptic loosening, wear, or malalignment. The longest reported follow-up length was 120 months for acetabular cages and 96 months for acetabular cups. The AM implants have proven to serve as an excellent option to restore premorbid skeletal anatomy of the pelvis.

3D-printed individualized navigation template versus the fluoroscopic guide to defining the femoral tunnel for medial patellofemoral ligament reconstruction: A retrospective study

During medial patellofemoral ligament (MPFL) reconstruction, fluoroscopic determination of the femoral tunnel point is the most common method. However, there is a decrease in tunnel position accuracy due to rotation of the femur during fluoroscopy, as well as the damage to the operator from multiple fluoroscopies, whereas the 3D-printed individualized navigation template is not affected by this factor. This study focuses on the accuracy and early clinical efficacy of 2 different ways to determine the femoral tunnel (Schöttle point) for double-bundle isometric MPFL reconstruction. This is a retrospective study, conducted between 2016 and 2019, in which 60 patients with recurrent patellar dislocation were divided into 2 groups: 30 with MPFL reconstruction at the Schöttle point determined by 3D-printed individualized navigation template (group A) and 30 with MPFL reconstruction at the Schöttle point determined by fluoroscopic guidance (group B). The changes in patella congruence angle and patella tilt angle before and after surgery were assessed using computed tomography scans of the knee, knee function was assessed using the Kujala knee score and the international knee documentation committee (IKDC) score, and the 2 approaches were compared for the intraoperative establishment of the femoral tunnel position at a distance from Schöttle point. At a minimum of 3 years follow-up, patella tilt angle and patella congruence angle returned to normal levels and were statistically different from the preoperative range, with no significant differences between the 2 groups at the same period, and Kujala and IKDC scores of knee function were significantly improved in both groups after surgery. The mean Kujala and IKDC scores were statistically different between groups A and B at 3 and 6 months postoperatively. No statistically significant differences were seen between the 2 groups at the final follow-up. Both femoral tunnel localization approaches for double-bundle isometric MPFL reconstruction resulted in good knee function. At no < 3 years of follow-up, the use of a 3D-printed individualized navigation template did result in more accurate isometric points and higher knee function scores in the early postoperative period.

Complex geometry and integrated macro-porosity: Clinical applications of electron beam melting to fabricate bespoke bone-anchored implants

The last decade has witnessed rapid advancements in manufacturing technologies for biomedical implants. Additive manufacturing (or 3D printing) has broken down major barriers in the way of producing complex 3D geometries. Electron beam melting (EBM) is one such 3D printing process applicable to metals and alloys. EBM offers build rates up to two orders of magnitude greater than comparable laser-based technologies and a high vacuum environment to prevent accumulation of trace elements. These features make EBM particularly advantageous for materials susceptible to spontaneous oxidation and nitrogen pick-up when exposed to air (e.g., titanium and titanium-based alloys). For skeletal reconstruction(s), anatomical mimickry and integrated macro-porous architecture to facilitate bone ingrowth are undoubtedly the key features of EBM manufactured implants. Using finite element modelling of physiological loading conditions, the design of a prosthesis may be further personalised. This review looks at the many unique clinical applications of EBM in skeletal repair and the ground-breaking innovations in prosthetic rehabilitation. From a simple acetabular cup to the fifth toe, from the hand-wrist complex to the shoulder, and from vertebral replacement to cranio-maxillofacial reconstruction, EBM has experienced it all. While sternocostal reconstructions might be rare, the repair of long bones using EBM manufactured implants is becoming exceedingly frequent. Despite the various merits, several challenges remain yet untackled. Nevertheless, with the capability to produce osseointegrating implants of any conceivable shape/size, and permissive of bone ingrowth and functional loading, EBM can pave the way for numerous fascinating and novel applications in skeletal repair, regeneration, and rehabilitation. STATEMENT OF SIGNIFICANCE: Electron beam melting (EBM) offers unparalleled possibilities in producing contaminant-free, complex and intricate geometries from alloys of biomedical interest, including Ti6Al4V and CoCr. We review the diverse range of clinical applications of EBM in skeletal repair, both as mass produced off-the-shelf implants and personalised, patient-specific prostheses. From replacing large volumes of disease-affected bone to complex, multi-material reconstructions, almost every part of the human skeleton has been replaced with an EBM manufactured analog to achieve macroscopic anatomical-mimickry. However, various questions regarding long-term performance of patient-specific implants remain unaddressed. Directions for further development include designing personalised implants and prostheses based on simulated loading conditions and accounting for trabecular bone microstructure with respect to physiological factors such as patient's age and disease status.

Material parameters identification of 3D printed titanium alloy prosthesis stem based on response surface method

3D printed Titanium alloy is widely used as a material of artificial joints and its mechanical properties is a key factor for improving operation results. Because the elastic modulus of the 3 D printed titanium alloy specimen was related to the size of the metal blank. It is very difficult to identify mechanical parameters by traditional mechanics experiments. In this paper, according to the inverse analysis principle of the parameter estimation, a response surface methodology (RSM) was proposed to identify the mechanical parameters, based on finite element inverse analysis. The finite element models of femoral prosthesis stem were established in line with compression experiments. The material parameters were combined by central composite design (CCD), and the response surface (RS) models were constructed using a quadratic polynomial with cross terms and optimized using a genetic algorithm (GA). Finally, the best mechanical parameter combination of the femoral prosthesis was calculated. The calculated elastic modulus and Poisson's ratio of a 3 D printed titanium alloy femoral prosthesis stem were 109.07 GPa and 0.29, respectively, with the elastic modulus error being very small. The proposed method is effective and can be extended for the identification of mechanical parameters in other 3 D printed models.

Application of three-dimensional printing technology in peripheral hip diseases

The incidence of peripheral hip diseases is increasing every year, and its treatment is always tricky due to the complexity of hip joint anatomy and a variety of surgical methods. This paper summarizes the application research and progress of three-dimensional (3D) printing technology in different peripheral hip diseases in recent years published by PubMed from January 2017 to July 2021 with the search terms including “3D or three-dimensional, print*, and hip*. In general, the application of 3D printing technology is mainly to print bone models of patients, make surgical plans, and simulate pre-operation, customized surgical navigation templates for precise positioning or targeted resection of tissue or bone, and customized patient-specific instruments (PSI) fully conforms to the patient’s anatomical morphology. It mainly reduces operative time, intraoperative blood loss, and improves joint function. Consequently, 3D printing technology can be customized according to the patient’s disease condition, which provides a new option for treating complex hip diseases and has excellent application and development potential.

Impact of the COVID-19 pandemic on orthopedic fracture characteristics in three hospitals in Turkey: A multi-center epidemiological study

Objectives

In this study, we present the use of case specific three- dimensional (3D) printed plastic models and custom-made acetabular implants in orthopedic surgery.

Materials and methods

Between March 2018 and September 2020, surgeries were simulated using plastic models manufactured by 3D printers on the two patients with pilon fractures. Also, custom-made acetabular implants were used on two patients with an acetabular bone defect for the revision of total hip arthroplasty (THA).

Results

More comfortable surgeries were experienced in pilon fractures using preoperative plastic models. Similarly, during the follow-up period, the patients that applied custom-made acetabular implants showed a fixed and well-positioning in radiographic examination. These patients did not experience any surgical complications and achieved an excellent recovery.

Conclusion

Preoperative surgical simulation with 3D printed models can increase the comfort of fracture surgeries. Also, custom-made 3D printed acetabular implants can perform an important task in patients treated with revision THA surgery due to severe acetabular defects.