Host Bone Research Articles

The use of bovine-derived hydroxyapatite xenograft for defect filling in opening-wedge high tibial osteotomy.

A retrospective study was performed on all patients who received OW-HTO at Prof. Dr R. Soeharso Orthopaedic Hospital from November 2019 to December 2022. A total of 21 patients (24 knees) were included in this study. Clinical dan radiological evaluation was performed on all patients preoperative and postoperatively. The mean of the follow-up period was 12.6 months with a minimum of 4 months follow-up. Primary medial uni-compartment knee osteoarthritis was the most common diagnosis, with 17 of 24 cases (70.8%). Mechanical axis deviation was changed from 31mm medial deviation (range: 8-52mm) to 0.45mm medial deviation (range: 13 - (-8) mm). The anatomic tibiofemoral angle was corrected from a preoperative mean of 4.7° of varus to a mean of 5.8° of valgus postoperatively. Bone defect height was mean 15.9mm with a range of 10-23mm. Bone defect width was mean 46.7mm (range: 34-60mm). Hydroxyapatite graft integration with the host bone was found in all patients during the final follow-up period. Bovine-derived hydroxyapatite graft is a safe and effective material for bone defect filling in OW-HTO procedures with a high bone union rate.

Clinical analysis of the usefulness of letermovir for prevention of cytomegalovirus infection after haploidentical hematopoietic stem cell transplantation

Objective: To analyze the efficacy and safety of letermovir in primary prophylaxis of cytomegalovirus (CMV) reactivation in patients receiving haploidentical hematopoietic stem cell transplantation. Methods: This retrospective, cohort study was conducted using data of patients who underwent haploidentical transplantation at Peking University Institute of Hematology and received letermovir for primary prophylaxis between May 1, 2022 and August 30, 2022. The inclusion criteria of the letermovir group were as follows: letermovir initiation within 30 days after transplantation and continuation for≥90 days after transplantation. Patients who underwent haploidentical transplantation within the same time period but did not receive letermovir prophylaxis were selected in a 1∶4 ratio as controls. The main outcomes were the incidence of CMV infection and CMV disease after transplantation as well as the possible effects of letermovir on acute graft versus host disease (aGVHD), non-relapse mortality (NRM), and bone marrow suppression. Categorical variables were analyzed by chi-square test, and continuous variables were analyzed by Mann-Whitney U test. The Kaplan-Meier method was used for evaluating incidence differences. Results: Seventeen patients were included in the letermovir prophylaxis group. The median patient age in the letermovir group was significantly greater than that in the control group (43 yr vs. 15 yr; Z=-4.28, P<0.001). The two groups showed no significant difference in sex distribution and primary diseases, etc. (all P>0.05). The proportion of CMV-seronegative donors was significantly higher in the letermovir prophylaxis group in comparison with the control group (8/17 vs. 0/68, χ2=35.32, P<0.001). Three out of the 17 patients in the letermovir group experienced CMV reactivation, which was significantly lower than the incidence of CMV reactivation in the control group (3/17 vs. 40/68, χ2=9.23, P=0.002), and no CMV disease development observed in the letermovir group. Letermovir showed no significant effects on platelet engraftment (P=0.105), aGVHD (P=0.348), and 100-day NRM (P=0.474). Conclusions: Preliminary data suggest that letermovir may effectively reduce the incidence of CMV infection after haploidentical transplantation without influencing aGVHD, NRM, and bone marrow suppression. Prospective randomized controlled studies are required to further verify these findings.

Outcome of Limb Salvaging Procedure for Bone Tumor Using Liquid Nitrogen Technique: A Case Series of 21 Patients

Abstract Introduction and importance: Autologous bone graft treated with liquid nitrogen is an option for biological reconstruction of bone defects in patients receiving tumor resection. This is the first report in Hong Kong on the outcome of this biological reconstruction in terms of functional outcome, local recurrence rate, and prognosis. Case presentation: From 2015 to 2021, 21 patients with bone tumor resection and reconstruction using liquid nitrogen treated autologous bone graft were recruited. The medical records and radiological images were retrieved for retrospective review. After delivery of the specimen, all the soft tissue of the excised bone was removed at the back table before cryotherapy. The auto graft was immersed in liquid nitrogen for 20 minutes, and thawed at room temperature for 10 minutes. After that the autograft was immersed in distilled water for 15 minutes before being incorporated into the reconstruction. All of them were followed up for at least one year post-operation. Clinical discussion: The mean union time was 13.3 months (from 4 to 31 months). The mean Musculoskeletal Tumor Society (MSTS) score was 22.6 (from 12 to 30). The mean follow up time was 38.2 months (from 12 to 64 months). There were two local soft tissue recurrences and one local recurrence from host bone. Conclusion: Autologous bone graft treated with liquid nitrogen is a safe option for biological reconstruction of bone defects after tumor resection. It provides satisfactory outcomes with low local recurrence rate, as well as comparable complications with other reconstruction methods.

Biomechanical Performance of a Novel Implant Design in Simulated Extraction Sites and Sinuslift Procedures

With increasing experience and in an attempt to shorten overall treatment times, implant placement in combination with tooth extractions and sinus lift procedures has become popular. In both cases, primary stability has to be achieved by either engaging apical and oral regions of trabecular bone or by engaging residual host bone beneath the sinus cavity. Extraction sites were formed by pressing a root analog into homogeneous low density polyurethane foam which was used as bone surrogate while a 3 mm thick sheet of medium density foam was used for mimicking a sinus lift situation. Two types (n = 10) of bone level implants with a conventional tapered design and a cervical back taper (NobelActive; control) and a novel design characterized by a shift in core diameter and thread geometry (AlfaGate; test) were placed in these models following conventional osteotomy preparation. Insertion torque was measured using a surgical motor and primary stability was determined by resonance frequency analysis. Statistical analysis was based on Welch two sample t tests with the level of significance set at α = 0.05. In sinuslifting, NobelActive implants required significantly higher insertion torques as compared to AlfaGate (p = 0.000) but did not achieve greater implant stability (p = 0.076). In extraction sites, AlfaGate implants showed both, significantly higher insertion torques (p = 0.004) and significantly greater implant stability (p = 0.000). The novel implant design allowed for greater primary stability when being placed in simulated extraction sockets and sinuslift situations. While in extraction sockets the position of condensing threads in combination with an increase in core diameter is beneficial, the deep cervical threads of the novel implant lead to superior performance in sinuslift situations.

Mean 14-year Outcomes of Hybrid Total Hip Arthroplasty Using Bulk Femoral Head Autografts for Acetabular Reconstruction

BackgroundWe aimed to evaluate the mean 14-year outcomes of hybrid total hip arthroplasty (THA) with cementless acetabular cups using bulk femoral head autografts in acetabular reconstruction and specify the radiological characteristics of cementless acetabular cups using this technique. MethodsThis retrospective study included 98 patients (123 hips) who underwent hybrid THA with a cementless acetabular cup using bulk femoral head autografts for bone deficiency in acetabular dysplasia and who were followed-up for a mean of 14 years (range, 10 to 19.6). The percentage of bone coverage index (BCI) and cup center–edge (CE) angles were evaluation radiologically of acetabular host bone coverage. The survival rate of the cementless acetabular cup and autograft bone ingrowth were assessed. ResultsThe survival rate with all revisions of cementless acetabular cups was 97.1% (95% confidence interval: 91.2 to 99.1). The autograft bone was remodeled or reoriented in all cases except in 2 hips where the bulk femoral head autograft collapsed. Radiological evaluation revealed a mean cup CE angle of −17.8° (range, −52 to −7°) and a BCI of 44.4% (range, 10 to 75.4%). ConclusionCementless acetabular cups using bulk femoral head autografts for bone deficiency of the acetabular roof remained stable even if the average BCI was 44.4% and the average cup CE angle was −17.8°. Cementless acetabular cups using these techniques showed good 10-year to 19.6-year outcomes and viabilities of graft bones.

Stabilization of Bio-Oss® particulates using photocurable hydrogel to enhance bone regeneration by regulating macrophage polarization.

Bone substitutes are widely used in maxillofacial and oral surgeries. However, in clinical practice, bone substitutes with various forms, including separated particulates, powders, and blocks, have exhibited poor handling properties and space maintenance characteristics, resulting in long surgery procedures and unstable volume of the newly formed bone. Movable separated particulates with high stiffness have induced local inflammatory responses that hinder bone regeneration. The present study aimed to develop a new method to enhance the stability and operability of bone substitutes commonly used in dentistry by premixing with photocurable hydrogel GelMA. The GelMA-encapsulated particulate had a strong capacity to aggregate separated particulates and firmly attach to the host bone defect after photocuring compared to particulates alone. Additionally, macrophages at the surface of the GelMA-stabilized particulates tended to present a more M2-like phenotype than those at the surface of Bio-Oss®, leading to more MMR+ multinucleated giant cell formation and the induction of blood vessel invasion and new bone formation. In conclusion, this hydrogel-coated bone substitute strategy facilitates bone regeneration with increased operability, a stable volume of osteogenic space, and a favorable osteogenic microenvironment, indicating its potential value in the field of maxillofacial and oral surgeries when bone substitutes are needed.

Determining primary stability for adhesively stabilized dental implants

ObjectivesTo examine factors influencing the primary stability of dental implants when stabilized in over-sized osteotomies using a calcium phosphate-based adhesive cement was the objective.MethodsUsing implant removal torque measurements as a surrogate for primary stability, we examined the influence of implant design features (diameter, surface area, and thread design), along with cement gap size and curing time, on the resulting primary implant stability.ResultsRemoval torque values scaled with implant surface area and increasing implant diameters. Cement gap size did not alter the median removal torque values; however, larger gaps were associated with an increased spread of the measured values. Among the removal torque values measured, all were found to be above 32 Ncm which is an insertion torque threshold value commonly recommended for immediate loading protocols.ConclusionThe adhesive cement show potential for offering primary implant stability for different dental implant designs. In this study, the primary parameters influencing the measured removal torque values were the implant surface area and diameter. As the liquid cement prevents the use of insertion torque, considering the relationship between insertion and removal torque, removal torque can be considered a reliable surrogate for primary implant stability for bench and pre-clinical settings.Clinical relevanceAt present, the primary stability of dental implants is linked to the quality of the host bone, the drill protocol, and the specific implant design. The adhesive cement might find applications in future clinical settings for enhancing primary stability of implants under circumstances where this cannot be achieved conventionally.

Artroplastia total de cadera no cementada con techo armado en coxartrosis displásica, seguimiento medio de 7 años

Developmental dysplasia of the hip is the cause of approximately one third of secondary coxarthrosis. Anatomy alterations make it difficult to place a total hip prosthesis in its anatomical position and for it to be stable in the long term; there are several techniques to achieve this goal. In the present work, we used autograft of the femoral head (shelf graft or reinforced roof), to improve the coverage of the acetabular component with favorable results. Materials ad methodsSixteen cases were included in 14 patients with a diagnosis of developmental dysplasia of the hip (13 women and one man), the mean age was 44.3 years (range 35–68 years), with a mean follow-up of 7 years (range 1–15 years). All the cases were evaluated clinically and radiographically, to demonstrate the osseointegration of the graft and the functional results in the medium term. ResultsAll the acetabular components were placed in anatomical position (Ranawat technique), the mean percentage of host bone coverage was 54.53% (range 43.28–79.05%), obtaining additional coverage with the bone graft of 45.13%. Osseointegration of the graft of 100% at 12 weeks, resorption of the graft from the sixth month, stabilizing in the third postoperative year. Only one case of dislocation is reported, no cases of infection, loosening, heterotopic ossification or revision. ConclusionThis procedure has shown good functional results in the medium term with 100% osseointegration, despite cases of severe bone resorption of the graft that does not compromise the stability of the prosthesis.

Osteoimmunology: A Link between Gastrointestinal Diseases and Skeletal Health in Chickens.

Bone serves as a multifunctional organ in avian species, giving structural integrity to the body, aiding locomotion and flight, regulating mineral homeostasis, and supplementing calcium for eggshell formation. Furthermore, immune cells originate and reside in the bone marrow, sharing a milieu with bone cells, indicating a potential interaction in functions. In avian species, the prevalence of gastrointestinal diseases can alter the growth and the immune response, which costs a great fortune to the poultry industry. Previous studies have shown that coccidiosis and necrotic enteritis can dramatically reduce bone quality as well. However, possible mechanisms on how bone quality is influenced by these disease conditions have not yet been completely understood, other than the reduced feed intake. On the other hand, several mediators of the immune response, such as chemokines and cytokines, play a vital role in the differentiation and activation of osteoclasts responsible for bone resorption and osteoblasts for bone formation. In the case of Eimeria spp./Clostridium perfringens coinfection, these mediators are upregulated. One possible mechanism for accelerated bone loss after gastrointestinal illnesses might be immune-mediated osteoclastogenesis via cytokines-RANKL-mediated pathways. This review article thus focuses on osteoimmunological pathways and the interaction between host immune responses and bone biology in gastrointestinal diseases like coccidiosis and necrotic enteritis affecting skeletal health.

Ultraviolet Light-Based Micropattern Printing on Titanium Surfaces to Promote Early Osseointegration.

Patterned interfaces are widely used for surface modification of biomaterials because of a morphological unit similar to that of native tissue. However, engineering fast and cost-effective high-resolution micropatterns directly onto titanium surfaces remains a grand challenge. Herein, a simply designed ultraviolet (UV) light-based micropattern printing to obtain geometrical patterns on implant interfaces is fabricated by utilizing customized photomasks and titanium dioxide (TiO2 ) nanorods as a photo-responsive platform. The technique manipulates the cytoskeleton of micropatterning cells on the surface of TiO2 nanorods. The linear pattern surface shows the elongated morphology and parallel linear arrangements of human mesenchymal stem cells (hMSCs), significantly enhancing their osteogenic differentiation. In addition to the upregulated expression of key osteo-specific function genes in vitro, the accelerated osseointegration between the implant and the host bone is obtained in vivo. Further investigation indicates that the developed linear pattern surface has an outstanding effect on the cytoskeletal system, and finally activates Yes-Associated Protein (YAP)-mediated mechanotransduction pathways, initiating hMSCs osteogenic differentiation. This study not only offers a microfabrication method that can be extended to fabricate various shape- and size-controlled micropatterns on titanium surfaces, but also provides insight into the surface structure design for enhanced bone regeneration.

Bone Regeneration Using Mesenchymal Stromal Cells and Biocompatible Scaffolds: A Concise Review of the Current Clinical Trials.

Bone regenerative medicine is a clinical approach combining live osteoblast progenitors, such as mesenchymal stromal cells (MSCs), with a biocompatible scaffold that can integrate into host bone tissue and restore its structural integrity. Over the last few years, many tissue engineering strategies have been developed and thoroughly investigated; however, limited approaches have been translated to clinical application. Consequently, the development and clinical validation of regenerative approaches remain a centerpiece of investigational efforts towards the clinical translation of advanced bioengineered scaffolds. The aim of this review was to identify the latest clinical trials related to the use of scaffolds with or without MSCs to regenerate bone defects. A revision of the literature was performed in PubMed, Embase, and Clinicaltrials.gov from 2018 up to 2023. Nine clinical trials were analyzed according to the inclusion criteria: six presented in the literature and three reported in Clinicaltrials.gov. Data were extracted covering background trial information. Six of the clinical trials added cells to scaffolds, while three used scaffolds alone. The majority of scaffolds were composed of calcium phosphate ceramic alone, such as β-tricalcium phosphate (TCP) (two clinical trials), biphasic calcium phosphate bioceramic granules (three clinical trials), and anorganic bovine bone (two clinical trials), while bone marrow was the primary source of the MSCs (five clinical trials). The MSC expansion was performed in GMP facilities, using human platelet lysate (PL) as a supplement without osteogenic factors. Only one trial reported minor adverse events. Overall, these findings highlight the importance and efficacy of cell-scaffold constructs in regenerative medicine under different conditions. Despite the encouraging clinical results obtained, further studies are needed to assess their clinical efficacy in treating bone diseases to optimize their application.

Versatility of Transport Distraction Osteogenesis for Reconstruction of Lateral Mandibular Ablative Defects.

The reconstitution of form and function after maxillofacial tumor resection or traumatic bony defects is a challenge when considering reconstructive options. The reconstructive options will depend upon whether the tissues to be replaced included bone alone or both bone and soft tissue (composite resection). This study was carried out on nine patients who with benign tumors or cysts of the mandible that required segmental resection. Mandibular reconstruction using mandibular transport distraction osteogenesis was performed for all the cases. Depending on whether the condyle was spared or sacrificed, the type of mandibular transport distractor either fixed on the remnant condyle-ramus unit or had a condylar component replacing the resected condyles. Depending on the location of the defect, transport distraction was carried our anterior to posterior or posterior to anterior. A total of nine cases of benign mandibular pathologies were operated. Segmental resection with condylar preservation was carried out in seven cases, segmental resection with condylar resection was carried out in two cases. In cases with condylar resection, the reconstruction plate of the distractor device had a condylar component. Anterior to posterior transport distraction was carried out in seven cases, and posterior to anterior transport distraction carried out in two cases. The amount of distracted bone ranged from 38 to 46mm. Mandibular transport distraction osteogenesis offers a modality of reconstruction where the patient's native host bone is osteotomized and gradually distracted to induce the formation of regenerated osseous structure and soft tissue. Being cost-effective, not requiring a steep learning curve/long operative time, and not technically demanding as vascularized bone grafts/flaps, it is feasible in the Indian setup as a practical reconstructive option for benign jaw tumors.

Hierarchical helical carbon nanotube fibre as a bone-integrating anterior cruciate ligament replacement.

High rates of ligament damage require replacements; however, current synthetic materials have issues with bone integration leading to implant failure. Here we introduce an artificial ligament that has the required mechanical properties and can integrate with the host bone and restore movement in animals. The ligament is assembled from aligned carbon nanotubes formed into hierarchical helical fibres bearing nanometre and micrometre channels. Osseointegration of the artificial ligament is observed in an anterior cruciate ligament replacement model where clinical polymer controls showed bone resorption. A higher pull-out force is found after a 13-week implantation in rabbit and ovine models, and animals can run and jump normally. The long-term safety of the artificial ligament is demonstrated, and the pathways involved in integration are studied.

Design of a functionally graded porous uncemented acetabular component: Influence of polar gradation.

The functionally graded porous metal-backed (FGPMB) acetabular component has the potential to minimize strain-shielding induced bone resorption, caused by stiffness mismatch of implant and host bone. This study is aimed at a novel design of FGPMB acetabular component, which is based on numerical investigations of the mechanical behavior of acetabular components with regard to common failure scenarios, considering various daily activities and implant-bone interface conditions. Both radial and polar functional gradations were implemented, and the effects of the polar gradation exponent on the failure criteria were evaluated. The relationships between porosity and orthotropic mechanical properties of a tetrahedron-based unit cell were obtained using a numerical homogenization method. Strain-shielding in cancellous bone was relatively lesser for the FGPMB than solid metal-backing. Few nodes around the rim were susceptible to implant-bone interfacial debonding, irrespective of the polar gradation exponent. Although the most favorable bone remodeling predictions were obtained for a polar gradation exponent of 0.1, a sudden change in the porosity was observed near the rim of FGPMB. Bone remodeling patterns were similar for polar gradation exponent of 5.0 and solid metal-backing. Moreover, the volumetric wear was maximum and minimum for polar gradation exponents of 0.1 and 5, respectively. Furthermore, the micromotions of different polar gradation exponents were within a range (20-40 μm) that might facilitate bone ingrowth. Considering common failure mechanisms, the FGPMB having polar gradation exponents in the range of 0.1-0.5 appeared to be a viable alternative to the solid acetabular component, within which a gradation exponent of 0.25 seemed the most appropriate design parameter.

MODELLING OSTEOCHONDRAL GRAFT BEHAVIOUR IN TIBIOFEMORAL JOINTS

Autologous osteochondral grafting has demonstrated positive outcomes for treating articular cartilage defects by replacing the damaged region with a cylindrical graft consisting of bone with a layer of cartilage, taken from a non-loadbearing region of the knee. Despite positive clinical use, factors that cause graft subsidence or poor integration are relatively unknown. The aim of this study was to develop finite element (FE) models of osteochondral grafts within a tibiofemoral joint and to investigate parameters affecting osteochondral graft stability.Initial experimental tests on cadaveric femurs were performed to calibrate the bone properties and graft-bone frictional forces for use in corresponding FE models, generated from µCT scan data. The effects of cartilage defects and osteochondral graft repair were measured by examining contact pressure changes using in vitro tests on a single cadaveric human tibiofemoral joint. Six defects were created in the femoral condyles which were subsequently treated with osteochondral autografts or metal pins. Matching µCT scan-based FE models were created, and the contact patches were compared. Sensitivity to graft bone properties was investigated.The bone material properties and graft-bone frictional forces were successfully calibrated from the initial tests with good resulting levels of agreement (CCC=0.87). The tibiofemoral joint experiment provided a range of cases to model. These cases were well captured experimentally and represented accurately in the FE models. Graft properties relative to host bone had large effects on immediate graft stability despite limited changes to resultant cartilage contact pressure.Model confidence was built through extensive validation and sensitivity testing, and demonstrated that specimen-specific properties were required to accurately represent graft behaviour. The results indicate that graft bone properties affect the immediate stability, which is important for the selection of allografts and design of future synthetic grafts.AcknowledgementsSupported by the EPSRC-EP/P001076.

Substance P aggravates ligature-induced periodontitis in mice.

Periodontitis is one of the most common oral diseases in humans, affecting over 40% of adult Americans. Pain-sensing nerves, or nociceptors, sense local environmental changes and often contain neuropeptides. Recent studies have suggested that nociceptors magnify host response and regulate bone loss in the periodontium. A subset of nociceptors projected to periodontium contains neuropeptides, such as calcitonin gene-related peptide (CGRP) or substance P (SP). However, the specific roles of neuropeptides from nociceptive neural terminals in periodontitis remain to be determined. In this study, we investigated the roles of neuropeptides on host responses and bone loss in ligature-induced periodontitis. Deletion of tachykinin precursor 1 (Tac1), a gene that encodes SP, or treatment of gingiva with SP antagonist significantly reduced bone loss in ligature-induced periodontitis, whereas deletion of calcitonin related polypeptide alpha (Calca), a gene that encodes CGRP, showed a marginal role on bone loss. Ligature-induced recruitment of leukocytes, including neutrophils, and increase in cytokines leading to bone loss in periodontium was significantly less in Tac1 knockout mice. Furthermore, intra-gingival injection of SP, but not neurokinin A, induced a vigorous inflammatory response and osteoclast activation in alveolar bone and facilitated bone loss in ligature-induced periodontitis. Altogether, our data suggest that SP plays significant roles in regulating host responses and bone resorption in ligature-induced periodontitis.

A NOVEL 3D-PRINTED HYDROXYAPATITE/ARAGONITE BIODEGRADABLE BONE GRAFT SUBSTITUTE FOR BONE REGENERATION

Bone defects require implantable graft substitutes, especially porous and biodegradable biomaterial for tissue regeneration. The aim of this study was to fabricate and assess a 3D-printed biodegradable hydroxyapatite/calcium carbonate scaffold for bone regeneration.Materials and methods:A 3D-printed biodegradable biomaterial containing calcium phosphate and aragonite (calcium carbonate) was fabricated using a Bioplotter. The physicochemical properties of the material were characterised. The materials were assessed in vitro for cytotoxicity and ostegenic potential and in vivo in rat intercondylar Φ3mm bone defect model for 3 months and Φ5mm of mini pig femoral bone defects for 6 months.The results showed that the materials contained hydroxyapatite and calcium carbonate, with the compression strength of 2.49± 0.2 MPa, pore size of 300.00 ± 41mm, and porosity of 40.±3%. The hydroxyapatite/aragonite was not cytotoxic and it promoted osteogenic differentiation of human umbilical cord matrix mesenchymal stem cells in vitro. After implantation, the bone defects were healed in the treatment group whereas the defect of controlled group with gelatin sponge implantation remained non-union. hydroxyapatite/aragonite fully integrated with host bone tissue and bridged the defects in 2 months, and significant biodegradation was followed by host new bone formation. After implantation into Φ5mm femoral defects in mini pigs hydroxyapatite/aragonite were completed degraded in 6 months and fully replaced by host bone formation, which matched the healing and degradation of porcine allogenic bone graft.In conclusion, hydroxyapatite/aragonite is a suitable new scaffold for bone regeneration. The calcium carbonate in the materials may have played an important role in osteogenesis and material biodegradation.

THE IMPORTANCE OF PRESS-FIT AND THREE-POINT FIXATION IN TREATING LARGE ACETABULAR DEFECTS WITH POROUS TANTALUM COMPONENTS

First-time revision acetabular components have a 36% re-revision rate at 10 years in Australia, with subsequent revisions known to have even worse results. Acetabular component migration &gt;1mm at two years following revision THA is a surrogate for long term loosening. This study aimed to measure the migration of porous tantalum components used at revision surgery and investigate the effect of achieving press-fit and/or three-point fixation within acetabular bone.Between May 2011 and March 2018, 55 patients (56 hips; 30 female, 25 male) underwent acetabular revision THR with a porous tantalum component, with a post-operative CT scan to assess implant to host bone contact achieved and Radiostereometric Analysis (RSA) examinations on day 2, 3 months, 1 and 2 years. A porous tantalum component was used because the defects treated (Paprosky IIa:IIb:IIc:IIIa:IIIb; 2:6:8:22:18; 13 with pelvic discontinuity) were either deemed too large or in a position preventing screw fixation of an implant with low coefficient of friction. Press-fit and three-point fixation of the implant was assessed intra-operatively and on postoperative imaging.Three-point acetabular fixation was achieved in 51 hips (92%), 34 (62%) of which were press-fit. The mean implant to host bone contact achieved was 36% (range 9-71%). The majority (52/56, 93%) of components demonstrated acceptable early stability. Four components migrated &gt;1mm proximally at two years (1.1, 3.2, 3.6 and 16.4mm). Three of these were in hips with Paprosky IIIB defects, including 2 with pelvic discontinuity. Neither press-fit nor three-point fixation was achieved for these three components and the cup to host bone contact achieved was low (30, 32 and 59%).The majority of porous tantalum components had acceptable stability at two years following revision surgery despite treating large acetabular defects and poor bone quality. Components without press-fit or three-point fixation were associated with unacceptable amounts of early migration.

Study on the Friction and Wear Properties of PEEK Against Cortical Bone Tissue Under Different Lubricating Conditions.

The tribological behavior between orthopedic implants and cortical bone is important but usually neglected. Poly(ether-ether-ketone) (PEEK) is a promising material for orthopedic applications. To further understand and improve the interfacial tribological properties between PEEK implant and host bone tissue, a PEEK-cortical bone tribo-pair is designed and fabricated. The frictional and wear performance of such tribo-pair wasinvestigated under different lubricants, i.e., simulated body fluid (SBF), calf serum (CS), hyaluronic acid (HA), and mucin (MUC). The results suggest that MUC solution can be utilized as an artificial natural synovial fluid to improve the tribological properties of PEEK-based implants. This article is protected by copyright. All rights reserved.

Acetabular Component Removal Systems

As primary total hip arthroplasty procedures continue to rise, acetabular revision surgery will be in increasing demand. Treatment of acetabular component failure and associated bone defects depends on patient characteristics, the degree and location of bone loss, the ability of the columns to support biologic fixation, and the presence of pelvic discontinuity. In revision total hip arthroplasty, technological advances have been made to address limitations of acetabular cup removal while preserving host bone stock. The goal of acetabular revision reconstruction should be to obtain stable fixation and restore the hip center. The various acetabular cup removal systems are discussed.