FIVE YEAR OUTCOMES OF CERAMIC-ОN-CERAMIC AND CERAMIC-ОN-POLYETHYLENE BEARINGS IN HIP JOINT REPLACEMENT

In view of the increasing number of hip joint replacement volume there remains the key issue of improving prosthesis survivorship which directly depends on the friction couple. Material and methods. The authors have analyzed five year outcomes of two bearing types (head and insert) used in hip replacement: ceramic-on-ceramic (CoC) in 324 patients and ceramic-on-polyethylene (CoP) in 300 patients. Totally 550 patients were operated in the period starting 2010 till 2014, including 74 patients underwent bilateral hip replacement. The authors divided patients based on gender and also into three age groups: 20-40, 41-60 and 61-80 years old. The largest group comprised 156 women aged 41-60 years (28.4%). Additional grouping of patients was made based on gender, age and bearing diameter.36 mm diameter bearing was characterized of the most frequent use. Functional outcomes were assessed by Harris Hip Score. Statistical analysis was made with Statistica 10 software. Statistical significant was observed at p<0.05.Results.28 mm diameter bearing were rarely (19.5%) applied and mainly in women which is related to need for use of smaller acetabulum components and inability to implant a larger insert.36 mm diameter bearing were used most frequently, CoC articulation of36 mm was used in men in 34% of cases and in women – in 18.12% of cases.40 mm articulations were implanted in women two times less than in men which is related to a smaller diameter of acetabulum in women. Generally, CoC bearings were implanted more often in men which can be explained by a bigger social demand as well as a higher anti-luxation stability of large diameter bearings. Dislocations of implants occurred in 5 (0.91%) patients: in 4 patients with CoP bearingand in one patient with CoC articulation. Four revision procedures (0.64%) were made due to deep periprosthetic infection: two surgeries in each group. Harris Hip Score evaluation in CoC group demonstrated excellent and good outcomes in 99.2% of cases, and in CoP group – in 97.5% of cases.Conclusion. The authors observed no ceramic fractures or acoustic effects during 60 months follow up. It’s reasonable to increase CoC bearing diameter to achieve a better anti-luxation effect. CoC bearing selection should depend on patient’s activity and social demands but not only on the age. Based on study observations the authors forecast a higher survivorship of CoC couple within 15-20 years and expect to prove this conclusion in further studies

Comparative Evaluation of Custom-Made Components and Standard Implants for Acetabular Reconstruction in Revision Total Hip Arthroplasty

Background.The use of custom-made acetabular components is one of the promising methods for reconstruction of the acetabulum in cases of significant defects, including those associated with pelvic bone dissociation. It allows achieving stable fixation and restoring the biomechanics of the hip joint. Aimofthestudy to compare the results of using individually designed components, supportive antiprotrusion rings, augments, and hemispherical components in revision total hip arthroplasty for type IIIB bone defects according to Paprosky classification. Methods.The study analyzed the treatment outcomes of 90 patients with type IIIB bone defects who underwent revision total hip arthroplasty between 2017 and 2022. Patients were divided into three groups: the first group received individually designed acetabular components, the second group received augments with hemispheres, and the third group had antiprotrusion cages implanted. The analysis included the reasons for revision surgery, operation duration, blood loss volume, and type of revision procedure. Pain and functional outcomes were assessed with WOMAC, Harris Hip Score, and VAS scales. Results.3D-printed constructs were more frequently implanted in patients with pelvic bone dissociation. The first group showed a significantly positive dynamic in functional outcomes. Complications were diagnosed in 27 (30%) cases: joint instability (dislocation) in 10 (11.1%) patients, periprosthetic infection in 8 (8.8%), aseptic loosening in 4 (4.4%), and sciatic nerve neuropathy in 5 (5.5%) patients. The number of these complications was higher in the second and third groups of patients. Conclusion.Custom-made implants using 3D technologies are a preferable option for revision total hip arthroplasty in patients with type IIIB defects according to Paprosky classification, especially in cases of pelvic bone dissociation

Three-dimensional printing versus conventional machining in the creation of a meatal urethral dilator: Development and mechanical testing

Background: Three-dimensional (3D) printing is a promising technology, but the limitations are often poorly understood. We compare different 3D printing methods with conventional machining techniques in manufacturing meatal urethral dilators which were recently removed from the Australian market. Methods: A prototype dilator was 3D printed vertically orientated on a low-cost fused deposition modelling (FDM) 3D printer in polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS). It was also 3D printed horizontally orientated in ABS on a high-end FDM 3D printer with soluble support material, as well as on an SLS 3D printer in medical nylon. The dilator was also machined in stainless steel using a lathe. All dilators were tested mechanically in a custom rig by hanging calibrated weights from the handle until the dilator snapped. Results: The horizontally printed ABS dilator experienced failure at a greater load than the vertically printed PLA and ABS dilators, respectively (503 g vs 283 g vs 163 g, p < 0.001). The SLS nylon dilator and machined steel dilator did not fail. The steel dilator is the most expensive with a quantity of five at 98 USD each, but this decreases to 30 USD each for a quantity of 1000. In contrast, the cost for the SLS dilator is 33 USD each for five and 27 USD each for 1000. Conclusions: Low-cost FDM 3D printing is not a replacement for conventional manufacturing. 3D printing is best used for patient-specific parts, prototyping or manufacturing complex parts that have additional functionality that cannot otherwise be achieved

Periprosthetic infection diagnosis. Part 1: serology

Periprosthetic joint infection continues to be a challenging problem. The demand for total joint arthroplasty is increasing, and the burden of such infections is increasing even more rapidly, and they pose a great problem due to economic reasons and poor outcomes. This review describes the current knowledge regarding diagnosis of periprosthetic joint infection with testing erythrocyte sedimentation rate, serum C-reactive protein, Interleukin-6 and some other novel approaches

Variability in accuracy of prostate cancer segmentation among radiologists, urologists, and scientists

BackgroundThere is increasing research in using segmentation of prostate cancer to create a digital 3D model from magnetic resonance imaging (MRI) scans for purposes of education or surgical planning. However, the variation in segmentation of prostate cancer among users and potential inaccuracy has not been studied.MethodsFour consultant radiologists, four consultant urologists, four urology trainees, and four nonclinician segmentation scientists were asked to segment a single slice of a lateral T3 prostate tumor on MRI (“Prostate 1”), an anterior zone prostate tumor MRI (“Prostate 2”), and a kidney tumor computed tomography (CT) scan (“Kidney”). Time taken and self‐rated subjective accuracy out of a maximum score of 10 were recorded. Root mean square error, Dice coefficient, Matthews correlation coefficient, Jaccard index, specificity, and sensitivity were calculated using the radiologists as the ground truth.ResultsThere was high variance among the radiologists in segmentation of Prostate 1 and 2 tumors with mean Dice coefficients of 0.81 and 0.58, respectively, compared to 0.96 for the kidney tumor. Urologists and urology trainees had similar accuracy, while nonclinicians had the lowest accuracy scores for Prostate 1 and 2 tumors (0.60 and 0.47) but similar for kidney tumor (0.95). Mean sensitivity in Prostate 1 (0.63) and Prostate 2 (0.61) was lower than specificity (0.92 and 0.93) suggesting under‐segmentation of tumors in the non‐radiologist groups. Participants spent less time on the kidney tumor segmentation and self‐rated accuracy was higher than both prostate tumors.ConclusionSegmentation of prostate cancers is more difficult than other anatomy such as kidney tumors. Less experienced participants appear to under‐segment models and underestimate the size of prostate tumors. Segmentation of prostate cancer is highly variable even among radiologists, and 3D modeling for clinical use must be performed with caution. Further work to develop a methodology to maximize segmentation accuracy is needed.<br/

CUSTOMIZED ACETABULAR COMPONENTS IN REVISION HIP ARTHROPLASTY

In recent years, there is a trend of increasing demand for revision hip arthroplasty. Among these patients there are many with complex acetabular defects, including patients with pelvic discontinuity. To ensure stability for revised acetabular components in such cases becomes a challenging or unachievable task. Such defects give indications for printing customized tri-flange acetabular component. The authors analysed own experience of creating and applying custom made acetabular components in 3 patients with complex acetabular defects. Material and methods. Among the patients there were 2 women and 1 man. Average age was 60,3±19,4 years (38 to 78 years). Two patients had III B defects with pelvic discontinuity and one patient had III A defect by Paprosky classification. As the first step, the authors in collaboration with engineers printed a plaster full size pelvic 3D model, as the second step a customized tri-flange acetabular component was designed and printed. Harris Hip Score was evaluated preoperatively and 3 months postoperatively. Results. Average follow-up period was 5,3±2,5 months (3 to 8 months). The authors observed no cases of implant loosening, dislocation or deep periprosthetic infection. Average Harris Hip Score before surgery was 27,13 and after surgery – 74,1 indicating a significant improvement in 3 months postoperatively. Conclusion. Indications for use of individual acetabular components in reported patients correspond to indications formulated by Berasi et al. The authors obtained encouraging early follow-up outcomes that correspond to data of other authors. In one patient certain difficulties were reported due to insufficient pelvic distraction. Component’s flanges prevented achieving adequate pelvic distraction. Nevertheless, good primary stability was achieved. Modern software and 3D metal printers can significantly reduce the production cost of customized acetabular components. Application of this technology can be widened to various orthopaedic centres and will undoubtedly improve the quality of treatment for such patients

3D Printing Improved Testicular Prostheses : Using Lattice Infill Structure to Modify Mechanical Properties

Patients often opt for implantation of testicular prostheses following orchidectomy for cancer or torsion. Recipients of testicular prostheses report issues regarding firmness, shape, size, and position, aspects of which relate to current limitations of silicone materials used and manufacturing methods for soft prostheses. We aim to create a 3D printable testicular prosthesis which mimics the natural shape and stiffness of a human testicle using a lattice infill structure. Porous testicular prostheses were engineered with relative densities from 0.1 to 0.9 using a repeating cubic unit cell lattice inside an anatomically accurate testicle 3D model. These models were printed using a multi-jetting process with an elastomeric material and compared with current market prostheses using shore hardness tests. Additionally, standard sized porous specimens were printed for compression testing to verify and match the stiffness to human testicle elastic modulus (E-modulus) values from literature. The resulting 3D printed testicular prosthesis of relative density between 0.3 and 0.4 successfully achieved a reduction of its bulk compressive E-modulus from 360 KPa to a human testicle at 28 Kpa. Additionally, this is the first study to quantitatively show that current commercial testicular prostheses are too firm compared to native tissue. 3D printing allows us to create metamaterials that match the properties of human tissue to create customisable patient specific prostheses. This method expands the use cases for existing biomaterials by tuning their properties and could be applied to other implants mimicking native tissues.</p

2D planning for hip arthroplasty

Hip arthroplasty is a common surgery, the success of which largely depends on its planning. Traditionally, arthroplasty planning performed on X-ray film, but this method has many shortcomings, including the well-known systematic repression for analogue X-ray systems to digital. The wide range of implant templates for the planning available in numerous of foreign special planning programs for arthroplasty, but all of them are very expensive. A team of authors from Sechenov First Moscow State Medical University, Lomonosov Moscow State University and Petrovsky National Research Centre of Surgery developed an original computer program for hip arthroplasty planning that allows to plan not only in the DICOM format, but also in photographs of traditional X-ray film. In the process of their work, it has been proved that the projection distortion when photographing X-ray applied to the X-ray viewer without a tripod is 1.95%. Practical testing of the planning program was carried out with 316 total hip arthroplasty surgeries. It turned out that for acetabular component the number of matches was 301 (95.3%), and for femoral components - 304 (96.2%). There were no cases of changing the type of components during surgeries. Thus, the created domestic import-substituting planning program allows working with a variety of image formats and making it possible to digitize X-ray film

Current applications of three-dimensional printing in urology

Three-dimensional (3D) printing or additive manufacturing is a new technology that has seen rapid development in recent years with decreasing costs. 3D printing allows the creation of customised, finely detailed constructs. Technological improvements, increased printer availability, decreasing costs, improved cell culture techniques, and biomaterials have enabled complex, novel and individualised medical treatments to be developed. Although the long-term goal of printing biocompatible organs has not yet been achieved, major advances have been made utilising 3D printing in biomedical engineering. In this literature review, we discuss the role of 3D printing in relation to urological surgery. We highlight the common printing methods employed and show examples of clinical urological uses. Currently, 3D printing can be used in urology for education of trainees and patients, surgical planning, creation of urological equipment, and bioprinting. In this review, we summarise the current applications of 3D-printing technology in these areas of urology.</p