Bioactivity Experimental Studies of Composite Materials Promising for Use in Traumatology and Orthopedics: Review

The aim of the study — to determine the properties of modern bioactive composite materials that have the greatest advantage for use in traumatology and orthopedics, particularly in spine surgery.Material and Methods. We performed a comprehensive literature search using PubMed, Medline, eLIBRARY and Semantic Scholar. The keywords “implants”, “biomaterials”, “composites”, “tissue engineering”, “scaffolds”, “graphene”, “hydrogels”, “3D bioprinting” were used to identify papers examining the topic of interest. We included comparative studies published from 2010 to 2020 in our review. The following properties were evaluated in papers: biotolerance, bioactivity, osteoconductivity, osteoinductivity, osteostimulation, mechanical strength.Results. Special attention is paid to the creation of composites. Composites are made by combining two or more materials to achieve biochemical and biomechanical properties. In composites production, a certain place is occupied by the technology of 3D bioprinting, thanks to which it is possible to develop an individual implant according to a given situation.Conclusion. The combination of composite materials properties indicating on their bioactivity and mechanical strength, as well as the use of 3D techniques to design the geometric forms of implants, provide a high potential for use in traumatology and orthopedics, particularly in spinal surgery.

How do 3D-printed primary uncemented acetabular components compare with established uncemented acetabular cups? The experience of the New Zealand National Joint Registry

Background: 3D-printed or additive manufactured acetabular implants are an exciting new technology being used in hip surgery with increasing frequency especially in complex acetabular reconstructions. However, the performance of acetabular components produced by this method for primary THR is unknown. Methods: 41,272 uncemented cups in primary THR for OA were identified in the NZJR for the purposed of this study. There were 39,080 uncemented cups in the control group (15,798 Pinnacle cups, 12,724 Trident cups and 10,558 RM Pressfit cups) compared to 2192 3D-printed uncemented implants (1397 Delta TT cups, 640 Ti Por and 155 Polymax cups). All-cause revision rates and reasons for revision were examined. Kaplan-Meier survival analysis was performed. Results: 3D-printed cups were inserted into younger, fitter patients with a higher mean BMI compared to those in the control group ( p < 0.001). The overall all-cause revision rate for 3D-printed cups was not significantly different to the controls: 0.77/100 cys (95% CI 0.59–1) compared to 0.55/100 cys (95% CI 0.52–0.58) in the control group ( p = 0.058, Hazards ratio 1.29, 95% CI 0.992–1.678). There was no difference in aseptic cup loosening or deep infection rates between either group or indeed individual implant designs. Conclusions: 3D-printed uncemented cups provide reliable survivorship and clinical results in primary THR comparable to established designs manufactured by traditional means. The theoretical concerns of increased rates of fatigue failure or deep infection are unsubstantiated.

A novel arthrodesis technique of the sacroiliac joint

Purpose The aim of the study was to develop an implant for fusion of the sacroiliac joint (SIJ) which, in contrast to known implant systems, can be used for isolated fusion of the SIJ as well as in combination with a lumbar instrumentation procedure or as an alternative to existing sacropelvic fixation (SPF) methods. Methods Following a comprehensive review of more than 200 high-resolution pelvic CT data sets, an implant body with high porosity and a large contact surface to the ilium and sacrum favoring integration was designed. Its shape was modeled based on the recess of the SIJ. A screw anchored in the ilium secures the position of the implant in the recess and allows connection to a lumbar instrumentation via an S1 screw. After receiving a detailed explanation and information about the novelty of the procedure, two patients with confirmed SIJ syndrome, who had undergone conservative treatment for more than 6 months without success, were operated on with a patient individual implant adapted to their anatomy. Results There were no intraoperative or postoperative complications. The postoperative CT and pelvic X-rays showed a good form fit of the implant body in the respective recess as well as correct positioning of the inserted screws. Conclusions The implant used first takes into account the special anatomy of the SIJ and also meets the requirements of a true arthrodesis of the joint. Clinical studies will now have to show whether the considerable theoretical advantages of the new implant system over existing SIJ implants and SPFs can be put into practice.

REHABILITATION OF THE ESTHETIC ZONE USING MULTIPLE ADJACENT INDIVIDUAL IMPLANT-SUPPORTED RESTORATIONS: WHERE ARE THE LIMITS?

Rehabilitation of the partially edentulous anterior maxilla is considered one of the most difficult challenges for the restorative dentist due to the esthetic, functional and psychological implications. Implant-supported restorations provide an appealing treatment alternative that responds to today’s patient expectations. The gold standard for this scenario has been the use of an implant-supported fixed partial denture with pontics that masks the soft tissue deficiencies, with acceptable esthetic results. However, nowadays patients are looking for individual single crowns since they believe that this type of restorations resemble the natural dentition, are easy to clean and floss. From the dentist perspective, they are easy to maintain and in case of prosthetic complications they can be repaired or changed without compromising the adjacent restorations. Three parameters have been identified that could guide the decision-making process when multiple adjacent implant supported restorations (MAISR) are selected as the treatment of choice: 1) Smile line 2) Inter-implant distance and tooth-implant distance 3) Patient's expectations and ability to clean.

Manipulation under Anesthesia: Does Polyethylene Thickness Matter?

Total knee arthroplasty (TKA) has been established as the most effective treatment for end-stage, symptomatic osteoarthritis of the knee. However, improper polyethylene size selection has been proposed to predispose patients to postoperative stiffness following TKA. The aim of this study is to evaluate if there is a correlation between the use of the thinnest tibial implant thickness and implant manufacturer with the likelihood of undergoing manipulation under anesthesia (MUA). A retrospective review of unilateral TKAs performed between January 2012 and November 2015 was performed. Each knee implant system was normalized by total tibial component thickness for each individual implant system (metal back plus polyethylene) and reaggregated to assess the difference in MUA rates when comparing the thinnest tibial component thickness against the next two sizes. Subset analysis was performed comparing the thinnest tibial component thickness for each individual implant system versus (1) all other tibial component sizes and (2) tibial components one and two sizes larger. A total of 2,728 patients were retrospectively evaluated, of which 71 (2.60%) underwent MUA. Combined tibial component thickness ranged from 8 to 21 mm. When aggregated together to compare the MUA rate between the thinnest liner and the next two sizes, no statistically significant difference was observed (p = 1). Subset analysis demonstrated inconsistent significant differences in MUA rates. Our results suggest that the polyethylene liner thickness alone is not a predictor of postoperative knee stiffness necessitating MUA. When selecting a polyethylene liner, a proper fit maximizing flexion/extension stability is the most crucial factor.

Adjacent Dental Implants Classification Based on Restorative Design

There is controversy in the literature regarding the indicated retentive mechanism for implant-supported crowns. When adjacent implants are restored, the restoration can be screw retained, cement retained, or a combination of cement and screw retained. Adjacent implant-supported crowns can be restored as individual implant supported crowns or can be splinted. A classification system is proposed when adjacent implants are restored. The classification system describes currently available options to restore adjacent implants. Six types of prosthetic design options are proposed as Class I through Class VI. In Class I design, individual cement-retained crowns are made. In Class II, individual screw-retained crowns are fabricated. Class III involves fabrication of individual screw-retrievable/cement-retained crowns. Class IV prosthetic design involves splinted cement-retained implant crowns. Class V prosthetic design involves splinted screw-retained crowns, and Class VI involves splinted screw-retrievable/cement-retained implant supported crowns.

Fabrication of Maxillofacial Implant Using CAD CAM System

We present an approach that combines Computer Tomography (CT), reverse engineering (RE) and rapid prototyping (RP) for individual implant production in maxillofacial surgery. 3D acquisition of the patient’s skull is performed, after acquisition of data; an individual computer-based 3D model of the bony defect is generated. These data are transferred into RE software to create the implant using a computer-aided design (CAD) model, which is directed into the RP machine for the production of the physical model. The implant is then directly used in investment casting such as “Quick Cast” pattern to produce the titanium model. In the clinical reports presented here, reconstructions of one patient with mandible bone defects were performed using this method. The custom prostheses perfectly fit the defects during the operations, and surgery time was reduced.