The Use of Tumor Prostheses for Primary or Revision Reverse Total Shoulder Arthroplasty With Proximal Humeral Bone Loss

Background During shoulder arthroplasty with substantial bone and soft tissue loss, reverse shoulder arthroplasty (RSA) with a tumor prosthesis may restore function, reduce pain, and improve implant fixation. Methods Thirteen adult patients undergoing RSA using a tumor prosthesis system were retrospectively reviewed. Preoperative visual analog score (VAS), single assessment numeric evaluation (SANE), American Shoulder and Elbow Surgeons (ASES) score, simple shoulder test (SST), and forward flexion were compared to latest follow up. Postoperative radiographs and complications were recorded. Results Mean age at surgery was 68.4 years. Eight patients had undergone at least 1 prior operation on the indicated shoulder. Six patients required wide excision of proximal humerus tumor. At mean of 34 months postoperatively, significant improvements were noted in VAS ( P = .03) and ASES score ( P = .04). Active forward elevation was 81.1 degrees. For all patients, postoperative radiographs demonstrated satisfactory alignment. Complications occurred in 38% of patients, with 31% requiring reoperation. Conclusion In cases of failed shoulder arthroplasty with excessive bone and soft tissue loss or substantial tumor burden, RSA with a tumor prosthesis can reduce pain levels and improve functional outcomes. However, forward elevation remains limited, and postoperative complications are a concern.

Studying the strength of the tibia during the replacement of a post-resection defect with a segmental allograft using locked intramedullary nailing (experimental clinical study)

Background. To achieve success in the incorporation of allografts and bone of the recipient, many factors are taken into account, which can be divided into two main groups: those related to sterilization and processing of the bone allograft and factors affecting the reliability of implant fixation in the bone of the recipient. The second important factor is the method for fixing the allografts and the bone of the recipient. The purpose was to determine the mechanical properties of bone after segmental bone alloplasty. Materials and methods. Female patient Sh., 30 years old, diagnosed with osteosarcoma of the left distal tibia T2N0M0 GIII, degree II, clinical group II, underwent polychemotherapy courses, surgical intervention according to the developed method. The tumor was removed en block, a post-resection defect was replaced with an articulating segmental bone allograft, fixed to the recipient’s bone through a stepped osteotomy and an intramedullary locked nail. Bone autografts were additionally placed into the area of the allograft contact with the recipient’s bone. After 2 years, the patient underwent surgery: amputation at the left third of the thigh. Radiographically, fusion of the allograft and the recipient’s bone was noted. An experimental study of the tensile strength of the tibia after segmental alloplasty of a post-resection defect was carried out using the developed surgical technique and a segmental allograft. Results. To compare the results of an experimental study of the tibia preparation after segmental bone alloplasty, data about the values of the ultimate strength of the bone tissue under compression and bending loads were selected. As shown by the experiment, the ultimate strength of the tibia preparation after its bone alloplasty was 51.82 MPa. This value corresponds to the minimum ultimate strength of a compact bone in bending — 51 MPa. Although this is twice as low as the maximum value of the ultimate strength of a compact bone in bending (133 MPa), it should be borne in mind that all the given reference values were obtained when testing intact preparations of a compact bone. Conclusions. The use of a segmental bone allograft to replace a post-resection defect in a long bone with its fixation to the recipient’s bone through a stepped osteotomy and locked intramedullary nailing with additional bone autoplasty in the area of the allograft contact with the recipient’s bone makes it possible to obtain in the osteotomy zone the bone, the ultimate strength of which corresponds to that of the intact tissue.

Enhanced osseointegration through direct energy deposition porous coating for cementless orthopedic implant fixation

Direct energy deposition (DED) is a newly developed 3D metal printing technique that can be utilized on a porous surface coating of joint implants, however there is still a lack of studies on what advantages DED has over conventional techniques. We conducted a systematic mechanical and biological comparative study of porous coatings prepared using the DED method and other commercially available technologies including titanium plasma spray (TPS), and powder bed fusion (PBF). DED showed higher porosity surface (48.54%) than TPS (21.4%) and PBF (35.91%) with comparable fatigue cycle. At initial cell adhesion, cells on DED and PBF surface appeared to spread well with distinct actin stress fibers through immunofluorescence study. It means that the osteoblasts bind more strongly to the DED and PBF surface. Also, DED surface showed higher cell proliferation (1.27 times higher than TPS and PBF) and osteoblast cell activity (1.28 times higher than PBF) for 2 weeks culture in vitro test. In addition, DED surface showed better bone to implant contact and new bone formation than TPS in in vivo study. DED surface also showed consistently good osseointegration performance throughout the early and late period of osseointegration. Collectively, these results show that the DED coating method is an innovative technology that can be utilized to make cementless joint implants.

On Measuring Implant Fixation Stability in ACL Reconstruction

Numerous methods and devices are available for implant fixation in anterior cruciate ligament (ACL) reconstruction. Biomechanical data indicate high variability in fixation stability across different devices. This study aims to provide a better insight into measuring the structural characteristics and mechanical behavior of ACL implant fixations. Fourteen human tibial specimens with reconstructed ACLs were subjected to progressively increasing dynamic loading until failure. The motions of the tibia, the proximal and distal graft ends, as well as the testing frame and actuator, were continuously recorded via a motion tracking system. Significantly higher displacements of the machine actuator (1.0 mm at graft slippage onset, and 12.2 mm at ultimate load) were measured compared to the displacements of the proximal (0.8 and 4.3 mm, respectively) and distal graft (0.1 and 3.4 mm, respectively) ends. The displacements measured at different sites showed significant correlations. The provided data suggest significant and systematic inaccuracies in the stiffness and slippage of the fixation when using machine displacement, as commonly reported in the literature. The assessment of the distal graft displacement excludes the artifactual graft elongation, and most accurately reflects the graft slippage onset indicating clinical failure. Considering the high displacement at the ultimate load, the ultimate load could be used as a standardized variable to compare different fixation methods. However, the ultimate load alone is not sufficient to qualitatively describe fixation stability.

Total ankle replacement

Introduction Total ankle replacement is definitely a tough issue for both orthopedic surgeons treating patients with ankle pathology and engineers who develop optimal implant constructs. Extreme short-time kinetic loads, complex motion biomechanics, anatomic features of the ankle result in high demands for ankle joint implants. In general, there is a positive tendency in an annual increase of the number of total ankle replacements. Alongside, a significant lagging in performing this procedure and the tendency for ankle arthrodesis has been observed in Russia. Aim To review the literature data about development and current status of total ankle replacement. To evaluate the use of modern implants for distal tibia replacement. Material and methods The given literature review includes analysis of foreign and domestic publications focused on issues of treatment of osteoarthritis of the ankle joint and tumors of the distal tibia. The information was searched for using GoogleScholar, PubMed, eLIBRARY, PubMedCentral in the Russian and English languages with the following keywords: total ankle replacement, ankle arthrodesis, ankle osteoarthritis, distal tibia replacement. Discussion Currently, there are controversies in selection of biomaterials and constructive parameters for ankle implants. Separately, there is an unsolved issue of selecting the optimal friction pair for bearing surfaces, as well as of operative technique features, such as implant fixation, surgical approach, modeling and restoration of the capsular-ligamentous complex. Conclusion Total ankle replacement is an effective alternative procedure to ankle arthrodesis and limb-sacrificing operations. To improve treatment results, optimal implant construction, fixation methods, selecting appropriate friction pair and capsular-ligamentous complex restoration should be further investigated in complex studies.

Incidence of Orthopedic Implant Removal, its Indications, and the Effect of the Covid-19 Pandemic

Aims & Objective. To assess the incidence and rate of implant removal among orthopedic patients, its indications, and the effect of COVID-19 pandemic. Material & Method: A retrospective study was done during the period from October 2017 to October 2020 included all patients admitted for removal of orthopedic implants. Results: One-hundred eleven patients with a mean age of 28 ± 10.9 years were included in this study. Most (83.8%) were males. The incidence rate of removal was 20.2%. The mean period between implant fixation and removal was 26 ± 20 months. Lower limb fractures constituted 85.6% of cases with about half of them as foot and ankle fractures. The most frequently presented fractures were femur and tibia (33.3% and 21.6%, respectively), while the most frequently removed implants were plate and screws (43.2%). Only 8.9% of surgeries were indicated for removal, and only 4.5% of all patients suffered post-removal complications. Conclusion: Non indicated implant removal occurs at a significantly high rate in Saudi Arabia. No real indications for such a procedure were found in the majority of patients. COVID-19 control strategies caused a significant decrease in this high rate. Keywords: COVID19; Orthopedics; Incidence Rate; Kingdom of Saudi Arabia; Bone Pins

Biomechanics in dental implants

Achieving primary stability in dental implants is crucial factor for accomplishing successful osteointegration with bone. Micro-motions higher than the threshold of 50 to 100 μm can lead to formation of fibrous tissue at the bone-to-implant interface. Therefore, osteointegration may be vitiated due to insufficient primary stability. Osseointegration is defined as a direct and functional connection between the implant biomaterial and the surrounding bone tissue. Osseointegration development requires an initial rigid implant fixation into the bone at the time of surgery and a secondary stage of new bone apposition directly onto the implant surface. Dental implants function to transfer the load to the surrounding biological tissues. Due to the absence of a periodontal ligament, its firm anchorage to bone, various forces acting on it and the presence of prosthetic components, they share a complex biomechanical relationship. The longevity of these osseointegrated implants depend on optimizing these complex interactions. Hence, the knowledge of forces acting on implant, design considerations of implant and bone mechanics is essential to fabricate an optimized implant supported prosthesis.

Management of chronic idiopathic pain in patients with dental implant without a clear pathological lesion: A retrospective study

Non-nociceptive, persistent idiopathic facial pain (PIFP) is a poorly localized, continuous dull pain that occurs even in the absence of apparent pathological lesions or clinical neurologic deficiency. This study aimed to investigate the disease characteristics of PIFP that developed after dental implant treatments. The clinical characteristics of pain as well as treatment method and outcomes were retrospectively analyzed in 20 patients diagnosed with PIFP. The patients developed pain either after implant fixation or prosthetic treatment. In most of the patients, the pain persisted not only around the implant region but also at a distant site from the related implant (13/20, 65%). Many patients desired removal of the implants to manage the pain although the pain was not considered to be related to the implant treatment itself. In 12 patients, the related implants were removed but 67% (n = 8/12) of the patients still experienced chronic pain after implant removal. Medication helped decrease the pain in most patients (n = 17). Pregabalin and clonazepam showed relatively higher efficiency than other medications for controlling the pain. The results showed that although the onset of PIFP was related to dental implant treatment, implant removal could not be considered a reliable option for the management of PIFP. Although medication controls the pain at least partially, complete pain control with medication should not be expected. These results demonstrate that an accurate diagnosis of PIFP is important for the selection of appropriate treatment.