Aims. We wanted to evaluate the effects of a bone anabolic agent (bone morphogenetic protein 2 (BMP-2)) on an anti-catabolic background (systemic or local zoledronate) on fixation of allografted revision implants. Methods. An established allografted revision protocol was implemented bilaterally into the stifle joints of 24 canines. At revision surgery, each animal received one BMP-2 (5 µg) functionalized implant, and one raw implant. One group (12 animals) received bone graft impregnated with zoledronate (0.005 mg/ml) before impaction. The other group (12 animals) received untreated bone graft and systemic zoledronate (0.1 mg/kg) ten and 20 days after revision surgery. Animals were observed for an additional four weeks before euthanasia. Results. No difference was detected on mechanical implant fixation (load to failure, stiffness, energy) between local or systemic zoledronate. Addition of BMP-2 had no effect on implant fixation. In the histomorphometric evaluation, implants with local zoledronate had more area of new bone on the
The development and pre-clinical evaluation of
nano-texturised, biomimetic, surfaces of titanium (Ti) implants treated
with titanium dioxide (TiO. 2. ) nanotube arrays is reviewed. In
vitro and in vivo evaluations show that
TiO. 2. nanotubes on Ti surfaces positively affect the osseointegration,
cell differentiation, mineralisation, and anti-microbial properties.
This surface treatment can be superimposed onto existing macro and
micro porous Ti implants creating a surface texture that also interacts
with cells at the nano level. Histology and mechanical pull-out testing
of specimens in rabbits indicate that TiO. 2. nanotubes
improves bone bonding nine-fold (p = 0.008). The rate of mineralisation
associated with TiO. 2. nanotube surfaces is about three
times that of non-treated Ti surfaces. In addition to improved osseointegration
properties, TiO. 2. nanotubes reduce the initial adhesion
and colonisation of Staphylococcus epidermidis.
Collectively, the properties of Ti
The aim of this study was to evaluate whether
coating titanium discs with selenium in the form of sodium selenite decreased
bacterial adhesion of In order to evaluate bacterial adhesion, sterile titanium discs
were coated with increasing concentrations of selenium and incubated
with bacterial solutions of The tested Selenium coating is a promising method to reduce bacterial attachment
on prosthetic material. Cite this article:
An experimental rabbit model was used to test the null hypothesis,
that there is no difference in new bone formation around uncoated
titanium discs compared with coated titanium discs when implanted
into the muscles of rabbits. A total of three titanium discs with different surface and coating
(1, porous coating; 2, porous coating + Bonemaster (Biomet); and
3, porous coating + plasma-sprayed hydroxyapatite) were implanted
in 12 female rabbits. Six animals were killed after six weeks and
the remaining six were killed after 12 weeks. The implants with
surrounding tissues were embedded in methyl methacrylate and grinded
sections were stained with Masson-Goldners trichrome and examined
by light microscopy of coded sections.Objectives
Methods
Aims. It is increasingly appreciated that coordinated regulation of angiogenesis and osteogenesis is needed for bone formation. How this regulation is achieved during peri-implant bone healing, such as osseointegration, is largely unclear. This study examined the relationship between angiogenesis and osteogenesis in a unique model of osseointegration of a mouse tibial implant by pharmacologically blocking the vascular endothelial growth factor (VEGF) pathway. Materials and Methods. An implant was inserted into the right tibia of 16-week-old female C57BL/6 mice (n = 38). Mice received anti-VEGF receptor-1 (VEGFR-1) antibody (25 mg/kg) and VEGF receptor-2 (VEGFR-2) antibody (25 mg/kg; n = 19) or an isotype control antibody (n = 19). Flow cytometric (n = 4/group) and immunofluorescent (n = 3/group) analyses were performed at two weeks post-implantation to detect the distribution and density of CD31. hi. EMCN. hi. endothelium. RNA sequencing analysis was performed using sorted CD31. hi. EMCN. hi. endothelial cells (n = 2/group). Osteoblast lineage cells expressing osterix (OSX) and osteopontin (OPN) were also detected with immunofluorescence. Mechanical pull-out testing (n = 12/group) was used at four weeks post-implantation to determine the strength of the bone-implant interface. After pull-out testing, the tissue attached to the
Periprosthetic joint infection (PJI) is one of the most dreaded complications after arthroplasty surgery; thus numerous approaches have been undertaken to equip metal surfaces with antibacterial properties. Due to its antimicrobial effects, silver is a promising coating for metallic surfaces, and several types of silver-coated arthroplasty implants are in clinical use today. However, silver can also exert toxic effects on eukaryotic cells both in the immediate vicinity of the coated implants and systemically. In most clinically-used implants, silver coatings are applied on bulk components that are not in direct contact with bone, such as in partial or total long bone arthroplasties used in tumour or complex revision surgery. These implants differ considerably in the coating method, total silver content, and silver release rates. Safety issues, such as the occurrence of argyria, have been a cause for concern, and the efficacy of silver coatings in terms of preventing PJI is also controversial. The application of silver coatings is uncommon on parts of implants intended for cementless fixation in host bone, but this option might be highly desirable since the modification of
Aims. Dual mobility implants in total hip arthroplasty are designed to increase the functional head size, thus decreasing the potential for dislocation. Modular dual mobility (MDM) implants incorporate a metal liner (e.g. cobalt-chromium alloy) in a metal shell (e.g. titanium alloy), raising concern for mechanically assisted crevice corrosion at the modular liner-shell connection. We sought to examine fretting and corrosion on MDM liners, to analyze the corrosion products, and to examine histologically the periprosthetic tissues. Methods. A total of 60 retrieved liners were subjectively scored for fretting and corrosion. The corrosion products from the three most severely corroded implants were removed from the
Aims. For cementless implants, stability is initially attained by an interference fit into the bone and osteo-integration may be encouraged by coating the implant with bioactive substances. Blood based autologous glue provides an easy, cost-effective way of obtaining high concentrations of growth factors for tissue healing and regeneration with the intention of spraying it onto the
Bacteriophages infect, replicate inside bacteria, and are released from the host through lysis. Here, we evaluate the effects of repetitive doses of the For the haematogenous infection, Aims
Methods
The December 2023 Knee Roundup360 looks at: Obesity is associated with greater improvement in patient-reported outcomes following primary total knee arthroplasty; Does mild flexion of the femoral prosthesis in total knee arthroplasty result in better early postoperative outcomes?; Robotic or manual total knee arthroplasty: a randomized controlled trial; Patient-relevant outcomes following first revision total knee arthroplasty, by diagnosis: an analysis of implant survivorship, mortality, serious medical complications, and patient-reported outcome measures using the National Joint Registry data set; Sagittal alignment in total knee arthroplasty: are there any discrepancies between robotic-assisted and manual axis orientation?; Tourniquet use does not impact recovery trajectory in total knee arthroplasty; Impact of proximal tibial varus anatomy on survivorship after medial unicondylar knee arthroplasty; Bone cement directly to the implant in primary total knee arthroplasty?; Maintaining joint line obliquity optimizes outcomes in patients with constitutionally varus knees.
Fracture-related infection (FRI) is commonly classified based on the time of onset of symptoms. Early infections (< two weeks) are treated with debridement, antibiotics, and implant retention (DAIR). For late infections (> ten weeks), guidelines recommend implant removal due to tolerant biofilms. For delayed infections (two to ten weeks), recommendations are unclear. In this study we compared infection clearance and bone healing in early and delayed FRI treated with DAIR in a rabbit model.
Aims
Methods
Periprosthetic fracture and implant loosening are two of the major reasons for revision surgery of cementless implants. Optimal implant fixation with minimal bone damage is challenging in this procedure. This pilot study investigates whether vibratory implant insertion is gentler compared to consecutive single blows for acetabular component implantation in a surrogate polyurethane (PU) model. Acetabular components (cups) were implanted into 1 mm nominal under-sized cavities in PU foams (15 and 30 per cubic foot (PCF)) using a vibratory implant insertion device and an automated impaction device for single blows. The impaction force, remaining polar gap, and lever-out moment were measured and compared between the impaction methods.Aims
Methods
The objective of this study was to compare the two-year migration and clinical outcomes of a new cementless hydroxyapatite (HA)-coated titanium acetabular shell with its previous version, which shared the same geometrical design but a different manufacturing process for applying the titanium surface. Overall, 87 patients undergoing total hip arthroplasty (THA) were randomized to either a Trident II HA or Trident HA shell, each cementless with clusterholes and HA-coating. All components were used in combination with a cemented Exeter V40 femoral stem. Implant migration was measured using radiostereometric analysis (RSA), with radiographs taken within two days of surgery (baseline), and at three, 12, and 24 months postoperatively. Proximal acetabular component migration was the primary outcome measure. Clinical scores and patient-reported outcome measures (PROMs) were collected at each follow-up.Aims
Methods
Several artificial bone grafts have been developed but fail to achieve anticipated osteogenesis due to their insufficient neovascularization capacity and periosteum support. This study aimed to develop a vascularized bone-periosteum construct (VBPC) to provide better angiogenesis and osteogenesis for bone regeneration. A total of 24 male New Zealand white rabbits were divided into four groups according to the experimental materials. Allogenic adipose-derived mesenchymal stem cells (AMSCs) were cultured and seeded evenly in the collagen/chitosan sheet to form cell sheet as periosteum. Simultaneously, allogenic AMSCs were seeded onto alginate beads and were cultured to differentiate to endothelial-like cells to form vascularized bone construct (VBC). The cell sheet was wrapped onto VBC to create a vascularized bone-periosteum construct (VBPC). Four different experimental materials – acellular construct, VBC, non-vascularized bone-periosteum construct, and VBPC – were then implanted in bilateral L4-L5 intertransverse space. At 12 weeks post-surgery, the bone-forming capacities were determined by CT, biomechanical testing, histology, and immunohistochemistry staining analyses.Aims
Methods
Temporary hemiepiphysiodesis (HED) is applied to children and adolescents to correct angular deformities (ADs) in long bones through guided growth. Traditional Blount staples or two-hole plates are mainly used for this indication. Despite precise surgical techniques and attentive postoperative follow-up, implant-associated complications are frequently described. To address these pitfalls, a flexible staple was developed to combine the advantages of the established implants. This study provides the first results of guided growth using the new implant and compares these with the established two-hole plates and Blount staples. Between January 2013 and December 2016, 138 patients (22 children, 116 adolescents) with genu valgum or genu varum were treated with 285 flexible staples. The minimum follow-up was 24 months. These results were compared with 98 patients treated with 205 two-hole plates and 92 patients treated with 535 Blount staples. In long-standing anteroposterior radiographs, mechanical axis deviations (MADs) were measured before and during treatment to analyze treatment efficiency. The evaluation of the new flexible staple was performed according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework (Stage 2a).Aims
Methods
A novel enhanced cement fixation (EF) tibial implant with deeper cement pockets and a more roughened bonding surface was released to market for an existing total knee arthroplasty (TKA) system.This randomized controlled trial assessed fixation of the both the EF (ATTUNE S+) and standard (Std; ATTUNE S) using radiostereometric analysis. Overall, 50 subjects were randomized (21 EF-TKA and 23 Std-TKA in the final analysis), and had follow-up visits at six weeks, and six, 12, and 24 months to assess migration of the tibial component. Low viscosity bone cement with tobramycin was used in a standardized fashion for all subjects. Patient-reported outcome measure data was captured at preoperative and all postoperative visits.Aims
Methods
Here we used a mature seven-day biofilm model of Mature biofilms of Aims
Methods
The management of periprosthetic joint infection (PJI) remains a major challenge in orthopaedic surgery. In this study, we aimed to characterize the local bone microstructure and metabolism in a clinical cohort of patients with chronic PJI. Periprosthetic femoral trabecular bone specimens were obtained from patients suffering from chronic PJI of the hip and knee (n = 20). Microbiological analysis was performed on preoperative joint aspirates and tissue specimens obtained during revision surgery. Microstructural and cellular bone parameters were analyzed in bone specimens by histomorphometry on undecalcified sections complemented by tartrate-resistant acid phosphatase immunohistochemistry. Data were compared with control specimens obtained during primary arthroplasty (n = 20) and aseptic revision (n = 20).Aims
Methods
Although low-intensity pulsed ultrasound (LIPUS) combined with disinfectants has been shown to effectively eliminate portions of biofilm in vitro, its efficacy in vivo remains uncertain. Our objective was to assess the antibiofilm potential and safety of LIPUS combined with 0.35% povidone-iodine (PI) in a rat debridement, antibiotics, and implant retention (DAIR) model of periprosthetic joint infection (PJI). A total of 56 male Sprague-Dawley rats were established in acute PJI models by intra-articular injection of bacteria. The rats were divided into four groups: a Control group, a 0.35% PI group, a LIPUS and saline group, and a LIPUS and 0.35% PI group. All rats underwent DAIR, except for Control, which underwent a sham procedure. General status, serum biochemical markers, weightbearing analysis, radiographs, micro-CT analysis, scanning electron microscopy of the prostheses, microbiological analysis, macroscope, and histopathology evaluation were performed 14 days after DAIR.Aims
Methods
Continuous local antibiotic perfusion (CLAP) has recently attracted attention as a new drug delivery system for orthopaedic infections. CLAP is a direct continuous infusion of high-concentration gentamicin (1,200 μg/ml) into the bone marrow. As it is a new system, its influence on the bone marrow is unknown. This study aimed to examine the effects of high-concentration antibiotics on human bone tissue-derived cells. Cells were isolated from the bone tissue grafts collected from six patients using the Reamer-Irrigator-Aspirator system, and exposed to different gentamicin concentrations. Live cells rate, apoptosis rate, alkaline phosphatase (ALP) activity, expression of osteoblast-related genes, mineralization potential, and restoration of cell viability and ALP activity were examined by in vitro studies.Aims
Methods
This aim of this study was to analyze the detection rate of rare pathogens in bone and joint infections (BJIs) using metagenomic next-generation sequencing (mNGS), and the impact of mNGS on clinical diagnosis and treatment. A retrospective analysis was conducted on 235 patients with BJIs who were treated at our hospital between January 2015 and December 2021. Patients were divided into the no-mNGS group (microbial culture only) and the mNGS group (mNGS testing and microbial culture) based on whether mNGS testing was used or not.Aims
Methods
Aims. Our intention was to investigate if the highly porous biological fixation surfaces of a new 3D-printed total knee arthroplasty (TKA) achieved adequate fixation of the tibial and patellar components to the underlying bone. Patients and Methods. A total of 29 patients undergoing primary TKA consented to participate in this prospective cohort study. All patients received a highly porous tibial baseplate and metal-backed patella. Patient-reported outcomes measures were recorded and implant migration was assessed using radiostereometric analysis. Results. Patient function significantly improved by three months postoperatively (p < 0.001). Mean difference in maximum total point motion between 12 and 24 months was 0.021 mm (-0.265 to 0.572) for the tibial implant and 0.089 mm (-0.337 to 0.758) for the patellar implant. The rate of tibial and patellar migration was largest over the first six postoperative weeks, with no changes in mean tibia migration occurring after six months, and no changes in mean patellar migration occurring after six weeks. One patellar component showed a rapid rate of migration between 12 and 24 months. Conclusion. Biological fixation appears to occur reliably on the highly porous
This study aimed to explore the role of small colony variants (SCVs) of A PJI diagnosis was made according to the MusculoSkeletal Infection Society (MSIS) for PJI. Bone and tissue samples were collected intraoperatively and the intracellular invasion and intraosseous colonization were detected. Transcriptomics of PJI samples were analyzed and verified by polymerase chain reaction (PCR).Aims
Methods
Micromotion of the polyethylene (PE) inlay may contribute to backside PE wear in addition to articulate wear of total knee arthroplasty (TKA). Using radiostereometric analysis (RSA) with tantalum beads in the PE inlay, we evaluated PE micromotion and its relationship to PE wear. A total of 23 patients with a mean age of 83 years (77 to 91), were available from a RSA study on cemented TKA with Maxim tibial components (Zimmer Biomet). PE inlay migration, PE wear, tibial component migration, and the anatomical knee axis were evaluated on weightbearing stereoradiographs. PE inlay wear was measured as the deepest penetration of the femoral component into the PE inlay.Aims
Methods
This study intended to investigate the effect of vericiguat (VIT) on titanium rod osseointegration in aged rats with iron overload, and also explore the role of VIT in osteoblast and osteoclast differentiation. In this study, 60 rats were included in a titanium rod implantation model and underwent subsequent guanylate cyclase treatment. Imaging, histology, and biomechanics were used to evaluate the osseointegration of rats in each group. First, the impact of VIT on bone integration in aged rats with iron overload was investigated. Subsequently, VIT was employed to modulate the differentiation of MC3T3-E1 cells and RAW264.7 cells under conditions of iron overload.Aims
Methods
The aims of this study were to identify and evaluate the current literature examining the prognostic factors which are associated with failure of total elbow arthroplasty (TEA). Electronic literature searches were conducted using MEDLINE, Embase, PubMed, and Cochrane. All studies reporting prognostic estimates for factors associated with the revision of a primary TEA were included. The risk of bias was assessed using the Quality In Prognosis Studies (QUIPS) tool, and the quality of evidence was assessed using the modified Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework. Due to low quality of the evidence and the heterogeneous nature of the studies, a narrative synthesis was used.Aims
Methods
Biofilm-related infection is a major complication that occurs in orthopaedic surgery. Various treatments are available but efficacy to eradicate infections varies significantly. A systematic review was performed to evaluate therapeutic interventions combating biofilm-related infections on in vivo animal models. Literature research was performed on PubMed and Embase databases. Keywords used for search criteria were “bone AND biofilm”. Information on the species of the animal model, bacterial strain, evaluation of biofilm and bone infection, complications, key findings on observations, prevention, and treatment of biofilm were extracted.Aims
Methods
Endoprosthetic reconstruction following distal femur tumour resection has been widely advocated. In this paper, we present the design of an uncemented endoprosthesis system featuring a short, curved stem, with the goal of enhancing long-term survivorship and functional outcomes. This study involved patients who underwent implantation of an uncemented distal femoral endoprosthesis with a short and curved stem between 2014 and 2019. Functional outcomes were assessed using the 1993 version of the Musculoskeletal Tumour Society (MSTS-93) score. Additionally, we quantified five types of complications and assessed osseointegration radiologically. The survivorship of the endoprosthesis was evaluated according to two endpoints. A total of 134 patients with a median age of 26 years (IQR 16 to 41) were included in our study. The median follow-up time was 61 months (IQR 56 to 76), and the median functional MSTS-93 was 83% (IQR 73 to 91) postoperatively.Aims
Methods
Objectives. Enhanced micromotions between the implant and surrounding bone can impair osseointegration, resulting in fibrous encapsulation and aseptic loosening of the implant. Since the effect of micromotions on human bone cells is sparsely investigated, an in vitro system, which allows application of micromotions on bone cells and subsequent investigation of bone cell activity, was developed. Methods. Micromotions ranging from 25 µm to 100 µm were applied as sine or triangle signal with 1 Hz frequency to human osteoblasts seeded on collagen scaffolds. Micromotions were applied for six hours per day over three days. During the micromotions, a static pressure of 527 Pa was exerted on the cells by Ti6Al4V cylinders. Osteoblasts loaded with Ti6Al4V cylinders and unloaded osteoblasts without micromotions served as controls. Subsequently, cell viability, expression of the osteogenic markers collagen type I, alkaline phosphatase, and osteocalcin, as well as gene expression of osteoprotegerin, receptor activator of NF-κB ligand, matrix metalloproteinase-1, and tissue inhibitor of metalloproteinase-1, were investigated. Results. Live and dead cell numbers were higher after 25 µm sine and 50 µm triangle micromotions compared with loaded controls. Collagen type I synthesis was downregulated in respective samples. The metabolic activity and osteocalcin expression level were higher in samples treated with 25 µm micromotions compared with the loaded controls. Furthermore, static loading and micromotions decreased the osteoprotegerin/receptor activator of NF-κB ligand ratio. Conclusion. Our system enables investigation of the behaviour of bone cells at the bone-implant interface under shear stress induced by micromotions. We could demonstrate that micromotions applied under static pressure conditions have a significant impact on the activity of osteoblasts seeded on collagen scaffolds. In future studies, higher mechanical stress will be applied and different
One of the main causes of tibial revision surgery for total knee arthroplasty is aseptic loosening. Therefore, stable fixation between the tibial component and the cement, and between the tibial component and the bone, is essential. A factor that could influence the implant stability is the implant design, with its different variations. In an existing implant system, the tibial component was modified by adding cement pockets. The aim of this experimental in vitro study was to investigate whether additional cement pockets on the underside of the tibial component could improve implant stability. The relative motion between implant and bone, the maximum pull-out force, the tibial cement mantle, and a possible path from the bone marrow to the metal-cement interface were determined. A tibial component with (group S: Attune S+) and without (group A: Attune) additional cement pockets was implanted in 15 fresh-frozen human leg pairs. The relative motion was determined under dynamic loading (extension-flexion 20° to 50°, load-level 1,200 to 2,100 N) with subsequent determination of the maximum pull-out force. In addition, the cement mantle was analyzed radiologically for possible defects, the tibia base cement adhesion, and preoperative bone mineral density (BMD).Aims
Methods
Although the short stem concept in hip arthroplasty procedure shows acceptable clinical performance, we sometimes get unexplainable radiological findings. The aim of this retrospective study was to evaluate changes of radiological findings up to three years postoperatively, and to assess any potential contributing factors on such radiological change in a Japanese population. This is a retrospective radiological study conducted in Japan. Radiological assessment was done in accordance with predetermined radiological review protocol. A total of 241 hips were included in the study and 118 hips (49.0%) revealed radiological change from immediately after surgery to one year postoperatively; these 118 hips were eligible for further analyses. Each investigator screened whether either radiolucent lines (RLLs), cortical hypertrophy (CH), or atrophy (AT) appeared or not on the one-year radiograph. Further, three-year radiographs of eligible cases were reviewed to determine changes such as, disappeared (D), improved (I), stable (S), and progression (P). Additionally, bone condensation (BC) was assessed on the three-year radiograph.Aims
Methods
Prior studies have identified that malseating of a modular dual mobility liner can occur, with previous reported incidences between 5.8% and 16.4%. The aim of this study was to determine the incidence of malseating in dual mobility implants at our institution, assess for risk factors for liner malseating, and investigate whether liner malseating has any impact on clinical outcomes after surgery. We retrospectively reviewed the radiographs of 239 primary and revision total hip arthroplasties with a modular dual mobility liner. Two independent reviewers assessed radiographs for each patient twice for evidence of malseating, with a third observer acting as a tiebreaker. Univariate analysis was conducted to determine risk factors for malseating with Youden’s index used to identify cut-off points. Cohen’s kappa test was used to measure interobserver and intraobserver reliability.Aims
Methods
The aims of this study were to develop an in vivo model of periprosthetic joint infection (PJI) in cemented hip hemiarthroplasty, and to monitor infection and biofilm formation in real-time. Sprague-Dawley rats underwent cemented hip hemiarthroplasty via the posterior approach with pre- and postoperative gait assessments. Infection with Aims
Methods
Four uncemented Symax hip stems were extracted at three weeks and nine, 13 and 32 months, respectively, for reasons other than loosening. The reasons for implant removal were infection in two cases, recurrent dislocation in one and acetabular fracture in one. They were analysed to assess the effect and behaviour of an electrochemically deposited, completely resorbable biomimetic BONIT-hydroxyapatite (HA) coating (proximal part) and a DOTIZE surface treatment (distal part) using qualitative histology, quantitative histomorphometry and scanning electron microscopy (SEM). Early and direct bone-implant bonding with signs of active remodelling of bone and the HA coating were demonstrated by histology and SEM. No loose BONIT-HA particles or delamination of the coating were observed, and there was no inflammation or fibrous interposition at the interface. Histomorphometry showed bone-implant contact varying between 26.5% at three weeks and 83.5% at 13 months at the HA-coated
Temporary epiphysiodesis (ED) is commonly applied in children and adolescents to treat leg length discrepancies (LLDs) and tall stature. Traditional Blount staples or modern two-hole plates are used in clinical practice. However, they require accurate planning, precise surgical techniques, and attentive follow-up to achieve the desired outcome without complications. This study reports the results of ED using a novel rigid staple (RigidTack) incorporating safety, as well as technical and procedural success according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework. A cohort of 56 patients, including 45 unilateral EDs for LLD and 11 bilateral EDs for tall stature, were prospectively analyzed. ED was performed with 222 rigid staples with a mean follow-up of 24.4 months (8 to 49). Patients with a predicted LLD of ≥ 2 cm at skeletal maturity were included. Mean age at surgery was 12.1 years (8 to 14). Correction and complication rates including implant-associated problems, and secondary deformities as well as perioperative parameters, were recorded (IDEAL stage 2a). These results were compared to historical cohorts treated for correction of LLD with two-hole plates or Blount staples.Aims
Methods
Periprosthetic joint infection (PJI) is a debilitating condition with a substantial socioeconomic burden. A novel autologous blood glue (ABG) has been developed, which can be prepared during surgery and sprayed onto prostheses at the time of implantation. The ABG can potentially provide an antimicrobial coating which will be effective in preventing PJI, not only by providing a physical barrier but also by eluting a well-known antibiotic. Hence, this study aimed to assess the antimicrobial effectiveness of ABG when impregnated with gentamicin and stem cells. Gentamicin elution from the ABG matrix was analyzed and quantified in a time-dependent manner. The combined efficiency of gentamicin and ABG as an anti-biofilm coating was investigated on titanium disks.Aims
Methods
Aseptic loosening is a leading cause of uncemented arthroplasty failure, often accompanied by fibrotic tissue at the bone-implant interface. A biological target, neutrophil extracellular traps (NETs), was investigated as a crucial connection between the innate immune system’s response to injury, fibrotic tissue development, and proper bone healing. Prevalence of NETs in peri-implant fibrotic tissue from aseptic loosening patients was assessed. A murine model of osseointegration failure was used to test the hypothesis that inhibition (through Patient peri-implant fibrotic tissue was analyzed for NETs biomarkers. To enhance osseointegration in loose implant conditions, an innate immune system pathway (NETs) was either inhibited (Aims
Methods
Hydroxyapatite (HA)-coated collars have been shown to reduce aseptic loosening of massive endoprostheses following primary surgery. Limited information exists about their effectiveness in revision surgery. The aim of this study was to radiologically assess osteointegration to HA-coated collars of cemented massive endoprostheses following revision surgery. Retrospective review of osseointegration frequency, pattern, and timing to a specific HA-coated collar on massive endoprostheses used in revision surgery at our tertiary referral centre between 2010 to 2017 was undertaken. Osseointegration was radiologically classified on cases with a minimum follow-up of six months.Aims
Methods
Periprosthetic joint infections (PJIs) and osteomyelitis are clinical challenges that are difficult to eradicate. Well-characterized large animal models necessary for testing and validating new treatment strategies for these conditions are lacking. The purpose of this study was to develop a rabbit model of chronic PJI in the distal femur. Fresh suspensions of Aims
Methods
We used an in vivo model to assess the use of an autogenous cancellous bone block and marrow graft for augmenting tendon reattachment to metallic implants. We hypothesised that augmentation of the tendon-implant interface with a bone block would enable retention of the graft on the
The use of 3D-printed titanium implant (DT) can effectively guide bone regeneration. DT triggers a continuous host immune reaction, including macrophage type 1 polarization, that resists osseointegration. Interleukin 4 (IL4) is a specific cytokine modulating osteogenic capability that switches macrophage polarization type 1 to type 2, and this switch favours bone regeneration. IL4 at concentrations of 0, 30, and 100 ng/ml was used at day 3 to create a biomimetic environment for bone marrow mesenchymal stromal cell (BMMSC) osteogenesis and macrophage polarization on the DT. The osteogenic and immune responses of BMMSCs and macrophages were evaluated respectively.Aims
Methods
Aims. Current treatments of prosthetic joint infection (PJI) are minimally effective against Staphylococcus aureus biofilm. A murine PJI model of debridement, antibiotics, and implant retention (DAIR) was used to test the hypothesis that PlySs2, a bacteriophage-derived lysin, can target S. aureus biofilm and address the unique challenges presented in this periprosthetic environment. Methods. The ability of PlySs2 and vancomycin to kill biofilm and colony-forming units (CFUs) on orthopaedic implants were compared using in vitro models. An in vivo murine PJI model of DAIR was used to assess the efficacy of a combination of PlySs2 and vancomycin on periprosthetic bacterial load. Results. PlySs2 treatment reduced 99% more CFUs and 75% more biofilm compared with vancomycin in vitro. A combination of PlySs2 and vancomycin in vivo reduced the number of CFUs on the
Biofilm formation is one of the primary reasons for the difficulty in treating implant-related infections (IRIs). Focused high-energy extracorporeal shockwave therapy (fhESWT), which is a treatment modality for fracture nonunions, has been shown to have a direct antibacterial effect on planktonic bacteria. The goal of the present study was to investigate the effect of fhESWT on
Aims
Methods
Cementless acetabular components rely on press-fit fixation for initial stability. In certain cases, initial stability is more difficult to obtain (such as during revision). No current study evaluates how a surgeon’s impaction technique (mallet mass, mallet velocity, and number of strikes) may affect component fixation. This study seeks to answer the following research questions: 1) how does impaction technique affect a) bone strain generation and deterioration (and hence implant stability) and b) seating in different density bones?; and 2) can an impaction technique be recommended to minimize risk of implant loosening while ensuring seating of the acetabular component? A custom drop tower was used to simulate surgical strikes seating acetabular components into synthetic bone. Strike velocity and drop mass were varied. Synthetic bone strain was measured using strain gauges and stability was assessed via push-out tests. Polar gap was measured using optical trackers.Aims
Methods
To compare the in vivo long-term fixation achieved by two acetabular components with different porous ingrowth surfaces using radiostereometric analysis (RSA). This was a minimum ten-year follow-up of a prospective randomized trial of 62 hips with two different porous ingrowth acetabular components. RSA exams had previously been acquired through two years of follow-up. Patients returned for RSA examination at a minimum of ten years. In addition, radiological appearance of these acetabular components was analyzed, and patient-reported outcome measures (PROMs) obtained.Aims
Methods
Limb salvage in bone tumour patients replaces the bone with massive segmental prostheses where achieving bone integration at the shoulder of the implant through extracortical bone growth has been shown to prevent loosening. This study investigates the effect of multidrug chemotherapy on extracortical bone growth and early radiological signs of aseptic loosening in patients with massive distal femoral prostheses. A retrospective radiological analysis was performed on adult patients with distal femoral arthroplasties. In all, 16 patients were included in the chemotherapy group with 18 patients in the non-chemotherapy control group. Annual radiographs were analyzed for three years postoperatively. Dimensions of the bony pedicle, osseointegration of the hydroxyapatite (HA) collar surface, bone resorption at the implant shoulder, and radiolucent line (RLL) formation around the cemented component were analyzed.Aims
Methods
This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys. Murine peritoneal macrophages were cultured and placed on stainless steel, CoCrMo, and Ti6Al4V discs into a 96-well plate. Cells were activated with interferon gamma and lipopolysaccharide. Macrophages on stainless steel discs produced significantly more nitric oxide (NO) compared to their control counterparts after eight to ten days and remained elevated for the duration of the experiment.Aims
Methods
Wear particles commonly used for experiments may carry adherent endotoxin on their surfaces, which may be responsible for the observed effects. In this study, we attached titanium plates to the tibiae of 20 rats. After osseointegration, endotoxin-contaminated or uncontaminated high-density-polyethylene (HDPE) particles were applied. Contaminated specimens showed a dramatic resorption of bone after seven days but new bone filled the site again at 21 days. Uncontaminated specimens showed no resorption. In 18 rats we implanted intramuscularly discs of ultra-high-molecular-weight polyethylene (UHMWPE) with baseline or excess contamination of endotoxin. Excess endotoxin disappeared within 24 hours and the amount of endotoxin remained at baseline level (contamination from production). Uncontaminated titanium discs did not adsorb endotoxin in vivo. The endotoxin was measured by analytical chemistry. Locally-applied endotoxin stimulated bone resorption similarly to that in experiments with wear particles. Endotoxin on the
We designed an in vivo study to determine if the superimposition of a microtexture on the surface of sintered titanium beads affected the extent of bone ingrowth. Cylindrical titanium intramedullary implants were coated with titanium beads to form a porous finish using commercial sintering techniques. A control group of implants was left in the as-sintered condition. The test group was etched in a boiling acidic solution to create an irregular surface over the entire porous coating. Six experimental dogs underwent simultaneous bilateral femoral intramedullary implantation of a control implant and an acid etched implant. At 12 weeks, the implants were harvested in situ and the femora processed for undecalcified, histological examination. Eight transverse serial sections for each implant were analysed by backscattered electron microscopy and the extent of bone ingrowth was quantified by computer-aided image analysis. The extent of bone ingrowth into the control implants was 15.8% while the extent of bone ingrowth into the etched implants was 25.3%, a difference of 60% that was statistically significant. These results are consistent with other research that documents the positive effect of microtextured surfaces on bone formation at an
Femoral revision component subsidence has been identified as predicting early failure in revision hip surgery. This comparative cohort study assessed the potential risk factors of subsidence in two commonly used femoral implant designs. A comparative cohort study was undertaken, analyzing a consecutive series of patients following revision total hip arthroplasties using either a tapered-modular (TM) fluted titanium or a porous-coated cylindrical modular (PCM) titanium femoral component, between April 2006 and May 2018. Clinical and radiological assessment was compared for both treatment cohorts. Risk factors for subsidence were assessed and compared.Aims
Methods
The aims of this study were to determine the effect of osteophyte excision on deformity correction and soft tissue gap balance in varus knees undergoing computer-assisted total knee arthroplasty (TKA). A total of 492 consecutive, cemented, cruciate-substituting TKAs performed for varus osteoarthritis were studied. After exposure and excision of both cruciates and menisci, it was noted from operative records the corrective interventions performed in each case. Knees in which no releases after the initial exposure, those which had only osteophyte excision, and those in which further interventions were performed were identified. From recorded navigation data, coronal and sagittal limb alignment, knee flexion range, and medial and lateral gap distances in maximum knee extension and 90° knee flexion with maximal varus and valgus stresses, were established, initially after exposure and excision of both cruciate ligaments, and then also at trialling. Knees were defined as ‘aligned’ if the hip-knee-ankle axis was between 177° and 180°, (0° to 3° varus) and ‘balanced’ if medial and lateral gaps in extension and at 90° flexion were within 2 mm of each other.Aims
Methods
Two acetabula which contained large bone allografts introduced at revision arthroplasty were obtained at post-mortem. The allografts had been placed in superior defects to support cementless acetabular components, and both hips were functioning well at the time of death. Clinical radiographs demonstrated apparent healing of graft to host bone, no graft collapse and stability of the acetabular components. Microscopic examination of sections through these specimens showed that the bulk allografts were encapsulated in fibrous tissue. Vascularity was increased at the host-graft interface, but there was limited evidence of bone union between the graft and the host. In the few areas where union had occurred, revascularisation extended no more than 2 mm beyond the graft-host interface. Within the body of the graft, the acellular matrix of trabecular bone maintained structural integrity up to 48 months after surgery. In areas where the allograft was adjacent to an implant, there was fibrous tissue orientated parallel to the
Biofilm formation is intrinsic to prosthetic joint infection (PJI). In the current study, we evaluated the effects of silver-containing hydroxyapatite (Ag-HA) coating and vancomycin (VCM) on methicillin-resistant Pure titanium discs (Ti discs), Ti discs coated with HA (HA discs), and 3% Ag-HA discs developed using a thermal spraying were inoculated with MRSA suspensions containing a mean in vitro 4.3 (SD 0.8) x 106 or 43.0 (SD 8.4) x 105 colony-forming units (CFUs). Immediately after MRSA inoculation, sterile phosphate-buffered saline or VCM (20 µg/ml) was added, and the discs were incubated for 24 hours at 37°C. Viable cell counting, 3D confocal laser scanning microscopy with Airyscan, and scanning electron microscopy were then performed. HA discs and Ag HA discs were implanted subcutaneously in vivo in the dorsum of rats, and MRSA suspensions containing a mean in vivo 7.2 (SD 0.4) x 106 or 72.0 (SD 4.2) x 105 CFUs were inoculated on the discs. VCM was injected subcutaneously daily every 12 hours followed by viable cell counting.Aims
Methods
Induction heating is a noninvasive, nonantibiotic treatment modality that can potentially be used to cause thermal damage to the bacterial biofilm on the metal implant surface. The purpose of this study was to determine the effectiveness of induction heating on killing
Aims
Methods
During revision procedures for aseptic reasons, there remains a suspicion that failure may have been the result of an undetected subclinical infection. However, there is little evidence available in the literature about unexpected positive results in presumed aseptic revision spine surgery. The aims of our study were to estimate the prevalence of unexpected positive culture using sonication and to evaluate clinical characteristics of these patients. All patients who underwent a revision surgery after instrumented spinal surgery at our institution between July 2014 and August 2016 with spinal implants submitted for sonication were retrospectively analyzed. Only revisions presumed as aseptic are included in the study. During the study period, 204 spinal revisions were performed for diagnoses other than infection. In 38 cases, sonication cultures were not obtained, leaving a study cohort of 166 cases. The mean age of the cohort was 61.5 years (Aims
Patients and Methods
The purpose of this study was to evaluate the biological fixation of a 3D printed porous implant, with and without different hydroxyapatite (HA) coatings, in a canine model. A canine transcortical model was used to evaluate the characteristics of bone ingrowth of Ti6Al4V cylindrical implants fabricated using laser rapid manufacturing (LRM). At four and 12 weeks post-implantation, we performed histological analysis and mechanical push-out testing on three groups of implants: a HA-free control (LRM), LRM with precipitated HA (LRM-PA), and LRM with plasma-sprayed HA (LRM-PSHA).Aims
Materials and Methods
Implant-related infection is one of the leading reasons for failure in orthopaedics and trauma, and results in high social and economic costs. Various antibacterial coating technologies have proven to be safe and effective both in preclinical and clinical studies, with post-surgical implant-related infections reduced by 90% in some cases, depending on the type of coating and experimental setup used. Economic assessment may enable the cost-to-benefit profile of any given antibacterial coating to be defined, based on the expected infection rate with and without the coating, the cost of the infection management, and the cost of the coating. After reviewing the latest evidence on the available antibacterial coatings, we quantified the impact caused by delaying their large-scale application. Considering only joint arthroplasties, our calculations indicated that for an antibacterial coating, with a final user’s cost price of €600 and able to reduce post-surgical infection by 80%, each year of delay to its large-scale application would cause an estimated 35 200 new cases of post-surgical infection in Europe, equating to additional hospital costs of approximately €440 million per year. An adequate reimbursement policy for antibacterial coatings may benefit patients, healthcare systems, and related research, as could faster and more affordable regulatory pathways for the technologies still in the pipeline. This could significantly reduce the social and economic burden of implant-related infections in orthopaedics and trauma.
Periprosthetic joint infection (PJI) is a serious complication
of total hip arthroplasty (THA). Different bearing surface materials
have different surface properties and it has been suggested that
the choice of bearing surface may influence the risk of PJI after
THA. The objective of this meta-analysis was to compare the rate
of PJI between metal-on-polyethylene (MoP), ceramic-on-polyethylene
(CoP), and ceramic-on-ceramic (CoC) bearings. Electronic databases (Medline, Embase, Cochrane library, Web
of Science, and Cumulative Index of Nursing and Allied Health Literature)
were searched for comparative randomized and observational studies
that reported the incidence of PJI for different bearing surfaces.
Two investigators independently reviewed studies for eligibility, evaluated
risk of bias, and performed data extraction. Meta-analysis was performed
using the Mantel–Haenzel method and random-effects model in accordance
with methods of the Cochrane group.Aims
Patients and Methods
Ultraviolet (UV) light-mediated photofunctionalisation is known to improve osseointegration of pure titanium (Ti). However, histological examination of titanium alloy (Ti6Al4V), which is frequently applied in orthopaedic and dental surgery, has not yet been performed. This study examined the osseointegration of photofunctionalised Ti6Al4V implants. Ti and Ti6Al4V implants were treated with UV light, and the chemical composition and contact angle on the surfaces were evaluated to confirm photofunctionalisation. The implants were inserted into femurs in rats, and the rats were killed two or four weeks after the surgery. For histomorphometric analysis, both the bone–implant contact (BIC) ratio and the bone volume (BV) ratio were calculated from histological analysis and microcomputed tomography data.Objectives
Methods
During the last decades, several research groups have used bisphosphonates for local application to counteract secondary bone resorption after bone grafting, to improve implant fixation or to control bone resorption caused by bone morphogenetic proteins (BMPs). We focused on zoledronate (a bisphosphonate) due to its greater antiresorptive potential over other bisphosphonates. Recently, it has become obvious that the carrier is of importance to modulate the concentration and elution profile of the zoledronic acid locally. Incorporating one fifth of the recommended systemic dose of zoledronate with different apatite matrices and types of bone defects has been shown to enhance bone regeneration significantly
The Intraosseous Transcutaneous Amputation Prosthesis (ITAP)
may improve quality of life for amputees by avoiding soft-tissue
complications associated with socket prostheses and by improving
sensory feedback and function. It relies on the formation of a seal
between the soft tissues and the implant and currently has a flange
with drilled holes to promote dermal attachment. Despite this, infection
remains a significant risk. This study explored alternative strategies
to enhance soft-tissue integration. The effect of ITAP pins with a fully porous titanium alloy flange
with interconnected pores on soft-tissue integration was investigated.
The flanges were coated with fibronectin-functionalised hydroxyapatite
and silver coatings, which have been shown to have an antibacterial
effect, while also promoting viable fibroblast growth Aims
Materials and Methods
The optimal method of tibial component fixation remains uncertain
in total knee arthroplasty (TKA). Hydroxyapatite coatings have been
applied to improve bone ingrowth in uncemented designs, but may
only coat the directly accessible surface. As peri-apatite (PA)
is solution deposited, this may increase the coverage of the implant
surface and thereby fixation. We assessed the tibial component fixation
of uncemented PA-coated TKAs Patients were randomised to PA-coated or cemented TKAs. In 60
patients (30 in each group), radiostereometric analysis of tibial
component migration was evaluated as the primary outcome at baseline,
three months post-operatively and at one, two and five years. A
linear mixed-effects model was used to analyse the repeated measurements.Aims
Patients and Methods
In order to address acetabular defects, porous metal revision acetabular components and augments have been developed, which require fixation to each other. The fixation technique that results in the smallest relative movement between the components, as well as its influence on the primary stability with the host bone, have not previously been determined. A total of 18 composite hemipelvises with a Paprosky IIB defect were implanted using a porous titanium 56 mm multihole acetabular component and 1 cm augment. Each acetabular component and augment was affixed to the bone using two screws, while the method of fixation between the acetabular component and augment varied for the three groups of six hemipelvises: group S, screw fixation only; group SC, screw plus cement fixation; group C, cement fixation only. The implanted hemipelvises were cyclically loaded to three different loading maxima (0.5 kN, 0.9 kN, and 1.8 kN).Objectives
Methods
Implant-related infection is one of the most devastating complications in orthopaedic surgery. Many surface and/or material modifications have been developed in order to minimise this problem; however, most of the We describe a method for the study of bacterial adherence in the presence of preosteoblastic cells. For this purpose we mixed different concentrations of bacterial cells from collection and clinical strains of staphylococci isolated from implant-related infections with preosteoblastic cells, and analysed the minimal concentration of bacteria able to colonise the surface of the material with image analysis.Objectives
Methods
Objectives. The surface of pure titanium (Ti) shows decreased histocompatibility over time; this phenomenon is known as biological ageing. UV irradiation enables the reversal of biological ageing through photofunctionalisation, a physicochemical alteration of the titanium
Osteosynthesis of anterior pubic ramus fractures using one large-diameter screw can be challenging in terms of both surgical procedure and fixation stability. Small-fragment screws have the advantage of following the pelvic cortex and being more flexible. The aim of the present study was to biomechanically compare retrograde intramedullary fixation of the superior pubic ramus using either one large- or two small-diameter screws. A total of 12 human cadaveric hemipelvises were analysed in a matched pair study design. Bone mineral density of the specimens was 68 mgHA/cm3 (standard deviation (Objectives
Materials and Methods
To assess the extent of osteointegration in two designs of shoulder
resurfacing implants. Bony integration to the Copeland cylindrical
central stem design and the Epoca RH conical-crown design were compared. Implants retrieved from six patients in each group were pair-matched.
Mean time to revision surgery of Copeland implants was 37 months
(standard deviation (Aims
Patients and Methods
We wished to investigate the influence of metal debris exposure
on the subsequent immune response and resulting soft-tissue injury
following metal-on-metal (MoM) hip arthroplasty. Some reports have
suggested that debris generated from the head-neck taper junction
is more destructive than equivalent doses from metal bearing surfaces. We investigated the influence of the source and volume of metal
debris on chromium (Cr) and cobalt (Co) concentrations in corresponding
blood and hip synovial fluid samples and the observed agglomerated
particle sizes in excised tissues using multiple regression analysis
of prospectively collected data. A total of 199 explanted MoM hips
(177 patients; 132 hips female) were analysed to determine rates
of volumetric wear at the bearing surfaces and taper junctions. Aims
Patients and Methods
Pathological assessment of periprosthetic tissues is important, not only for diagnosis, but also for understanding the pathobiology of implant failure. The host response to wear particle deposition in periprosthetic tissues is characterised by cell and tissue injury, and a reparative and inflammatory response in which there is an innate and adaptive immune response to the material components of implant wear. Physical and chemical characteristics of implant wear influence the nature of the response in periprosthetic tissues and account for the development of particular complications that lead to implant failure, such as osteolysis which leads to aseptic loosening, and soft-tissue necrosis/inflammation, which can result in pseudotumour formation. The innate response involves phagocytosis of implant-derived wear particles by macrophages; this is determined by pattern recognition receptors and results in expression of cytokines, chemokines and growth factors promoting inflammation and osteoclastogenesis; phagocytosed particles can also be cytotoxic and cause cell and tissue necrosis. The adaptive immune response to wear debris is characterised by the presence of lymphoid cells and most likely occurs as a result of a cell-mediated hypersensitivity reaction to cell and tissue components altered by interaction with the material components of particulate wear, particularly metal ions released from cobalt-chrome wear particles. Cite this article: Professor N. A. Athanasou. The pathobiology and pathology of aseptic implant failure.
Throughout the 20th Century, it has been postulated that the knee moves on the basis of a four-bar link mechanism composed of the cruciate ligaments, the femur and the tibia. As a consequence, the femur has been thought to roll back with flexion, and total knee arthroplasty (TKA) prostheses have been designed on this basis. Recent work, however, has proposed that at a position of between 0° and 120° the medial femoral condyle does not move anteroposteriorly whereas the lateral femoral condyle tends, but is not obliged, to roll back – a combination of movements which equates to tibial internal/ femoral external rotation with flexion. The aim of this paper was to assess if the articular geometry of the GMK Sphere TKA could recreate the natural knee movements The pattern of knee movement was studied in 15 patients (six male: nine female; one male with bilateral TKAs) with 16 GMK Sphere implants, at a mean age of 66 years (53 to 76) with a mean BMI of 30 kg/m2 (20 to 35). The motions of all 16 knees were observed using pulsed fluoroscopy during a number of weight-bearing and non-weight-bearing static and dynamic activities.Objectives
Methods
Nanotechnology is the study, production and controlled
manipulation of materials with a grain size <
100 nm. At this
level, the laws of classical mechanics fall away and those of quantum
mechanics take over, resulting in unique behaviour of matter in
terms of melting point, conductivity and reactivity. Additionally,
and likely more significant, as grain size decreases, the ratio
of surface area to volume drastically increases, allowing for greater interaction
between implants and the surrounding cellular environment. This
favourable increase in surface area plays an important role in mesenchymal
cell differentiation and ultimately bone–implant interactions. Basic science and translational research have revealed important
potential applications for nanotechnology in orthopaedic surgery,
particularly with regard to improving the interaction between implants
and host bone. Nanophase materials more closely match the architecture
of native trabecular bone, thereby greatly improving the osseo-integration
of orthopaedic implants. Nanophase-coated prostheses can also reduce
bacterial adhesion more than conventionally surfaced prostheses.
Nanophase selenium has shown great promise when used for tumour
reconstructions, as has nanophase silver in the management of traumatic
wounds. Nanophase silver may significantly improve healing of peripheral
nerve injuries, and nanophase gold has powerful anti-inflammatory
effects on tendon inflammation. Considerable advances must be made in our understanding of the
potential health risks of production, implantation and wear patterns
of nanophase devices before they are approved for clinical use.
Their potential, however, is considerable, and is likely to benefit
us all in the future. Cite this article:
Bactericidal levels of antibiotics are difficult
to achieve in infected total joint arthroplasty when intravenous antibiotics
or antibiotic-loaded cement spacers are used, but intra-articular
(IA) delivery of antibiotics has been effective in several studies.
This paper describes a protocol for IA delivery of antibiotics in
infected knee arthroplasty, and summarises the results of a pharmacokinetic
study and two clinical follow-up studies of especially difficult
groups: methicillin-resistant Cite this article:
A retrospective review was performed of patients
undergoing primary cementless total knee replacement (TKR) using
porous tantalum performed by a group of surgical trainees. Clinical
and radiological follow-up involved 79 females and 26 males encompassing
115 knees. The mean age was 66.9 years (36 to 85). Mean follow-up
was 7 years (2 to 11). Tibial and patellar components were porous
tantalum monoblock implants, and femoral components were posterior
stabilised (PS) in design with cobalt–chromium fibre mesh. Radiological
assessments were made for implant positioning, alignment, radiolucencies,
lysis, and loosening. There was 95.7% survival of implants. There
was no radiological evidence of loosening and no osteolysis found.
No revisions were performed for aseptic loosening. Average tibial
component alignment was 1.4° of varus (4°of valgus to 9° varus),
and 6.2° (3° anterior to 15° posterior) of posterior slope. Mean
femoral component alignment was 6.6° (1° to 11°) of valgus. Mean tibiofemoral
alignment was 5.6° of valgus (7° varus to 16° valgus). Patellar
tilt was a mean of 2.4° lateral (5° medial to 28° lateral). Patient
satisfaction with improvement in pain was 91%. Cementless TKR incorporating
porous tantalum yielded good clinical and radiological outcomes
at a mean of follow-up of seven-years. Cite this article:
We have assessed the different adhesive properties
of some of the most common bacteria associated with periprosthetic
joint infection on various types of ultra high molecular Weight
Polyethylene (UHMWPE). Quantitative Cite this article:
Our aim was to compare polylevolactic acid screws
with titanium screws when used for fixation of the distal tibiofibular
syndesmosis at mid-term follow-up. A total of 168 patients, with
a mean age of 38.5 years (18 to 72) who were randomly allocated
to receive either polylevolactic acid (n = 86) or metallic (n =
82) screws were included. The Baird scoring system was used to assess
the overall satisfaction and functional recovery post-operatively.
The demographic details and characteristics of the injury were similar
in the two groups. The mean follow-up was 55.8 months (48 to 66).
The Baird scores were similar in the two groups at the final follow-up.
Patients in the polylevolactic acid group had a greater mean dorsiflexion
(p = 0.011) and plantar-flexion of the injured ankles (p <
0.001).
In the same group, 18 patients had a mild and eight patients had
a moderate foreign body reaction. In the metallic groups eight had
mild and none had a moderate foreign body reaction (p <
0.001).
In total, three patients in the polylevolactic acid group and none
in the metallic group had heterotopic ossification (p = 0.246). We conclude that both screws provide adequate fixation and functional
recovery, but polylevolactic acid screws are associated with a higher
incidence of foreign body reactions. Cite this article:
This review examines the future of total hip arthroplasty, aiming to avoid past mistakes
The increasing need for total hip replacement
(THR) in an ageing population will inevitably generate a larger number
of revision procedures. The difficulties encountered in dealing
with the bone deficient acetabulum are amongst the greatest challenges
in hip surgery. The failed acetabular component requires reconstruction
to restore the hip centre and improve joint biomechanics. Impaction
bone grafting is successful in achieving acetabular reconstruction
using both cemented and cementless techniques. Bone graft incorporation
restores bone stock whilst providing good component stability. We
provide a summary of the evidence and current literature regarding impaction
bone grafting using both cemented and cementless techniques in revision
THR. Cite this article:
Impaction allograft is an established method of securing initial stability of an implant in arthroplasty. Subsequent bone integration can be prolonged, and the volume of allograft may not be maintained. Intermittent administration of parathyroid hormone has an anabolic effect on bone and may therefore improve integration of an implant. Using a canine implant model we tested the hypothesis that administration of parathyroid hormone may improve osseointegration of implants surrounded by bone graft. In 20 dogs a cylindrical porous-coated titanium alloy implant was inserted into normal cancellous bone in the proximal humerus and surrounded by a circumferential gap of 2.5 mm. Morsellised allograft was impacted around the implant. Half of the animals were given daily injections of human parathyroid hormone (1–34) 5 μg/kg for four weeks and half received control injections. The two groups were compared by mechanical testing and histomorphometry. We observed a significant increase in new bone formation within the bone graft in the parathyroid hormone group. There were no significant differences in the volume of allograft, bone-implant contact or in the mechanical parameters. These findings suggest that parathyroid hormone improves new bone formation in impacted morsellised allograft around an implant and retains the graft volume without significant resorption. Fixation of the implant was neither improved nor compromised at the final follow-up of four weeks.
We report the results at a mean of 24.3 years
(20 to 32) of 61 previously reported consecutive total hip replacements carried
out on 44 patients with severe congenital hip disease, performed
with reconstruction of the acetabulum with an impaction grafting
technique known as cotyloplasty. The mean age of the patients at
operation was 46.7 years (23 to 68) and all were women. The patients
were followed post-operatively for a mean of 24.3 years (20 to 32), using
the Merle d’Aubigné and Postel scoring system as modified by Charnley,
and with serial radiographs. At the time of the latest follow-up,
28 acetabular components had been revised because of aseptic loosening
at a mean of 15.9 years (6 to 26), and one at 40 days after surgery
because of repeated dislocations. The overall survival rate for aseptic
failure of the acetabular component at ten years was 93.1% (95%
confidence interval (CI) 86.5 to 96.7) when 53 hips were at risk,
and at 23 years was 56.1% (95% CI 49.4 to 62.8), when 22 hips remained
at risk. These long-term results are considered satisfactory for
the reconstruction of an acetabulum presenting with inadequate bone
stock and circumferential segmental defects. Cite this article:
We examined the mechanical properties of Vicryl (polyglactin 910) mesh Mesh fibres were visible at six weeks but had been completely resorbed by 12 weeks, with no evidence of chronic inflammation. The tendon-implant neoenthesis was predominantly an indirect type, with tendon attached to the bone-hydroxyapatite surface by perforating collagen fibres.
Impacted bone allograft is often used in revision joint replacement. Hydroxyapatite granules have been suggested as a substitute or to enhance morcellised bone allograft. We hypothesised that adding osteogenic protein-1 to a composite of bone allograft and non-resorbable hydroxyapatite granules (ProOsteon) would improve the incorporation of bone and implant fixation. We also compared the response to using ProOsteon alone against bone allograft used in isolation. We implanted two non-weight-bearing hydroxyapatite-coated implants into each proximal humerus of six dogs, with each implant surrounded by a concentric 3 mm gap. These gaps were randomly allocated to four different procedures in each dog: 1) bone allograft used on its own; 2) ProOsteon used on its own; 3) allograft and ProOsteon used together; or 4) allograft and ProOsteon with the addition of osteogenic protein-1. After three weeks osteogenic protein-1 increased bone formation and the energy absorption of implants grafted with allograft and ProOsteon. A composite of allograft, ProOsteon and osteogenic protein-1 was comparable, but not superior to, allograft used on its own. ProOsteon alone cannot be recommended as a substitute for allograft around non-cemented implants, but should be used to extend the volume of the graft, preferably with the addition of a growth factor.
The April 2012 Research Roundup360 looks at who is capable of being an arthroscopist, bupivacaine, triamcinolone and chondrotoxicity, reducing scarring in injured skeletal muscle, horny Goat Weed and the repair of osseous defects, platelet-derived growth factor and fracture healing, the importance of the reserve zone in a child’s growth plate, coping with advanced arthritis, hydroxyapatite and platelet-rich plasma for bone defects, and calcium phosphate and bone regeneration
The success of long-term transcutaneous implants
depends on dermal attachment to prevent downgrowth of the epithelium
and infection. Hydroxyapatite (HA) coatings and fibronectin (Fn)
have independently been shown to regulate fibroblast activity and
improve attachment. In an attempt to enhance this phenomenon we
adsorbed Fn onto HA-coated substrates. Our study was designed to
test the hypothesis that adsorption of Fn onto HA produces a surface
that will increase the attachment of dermal fibroblasts better than
HA alone or titanium alloy controls. Iodinated Fn was used to investigate the durability of the protein
coating and a bioassay using human dermal fibroblasts was performed
to assess the effects of the coating on cell attachment. Cell attachment
data were compared with those for HA alone and titanium alloy controls
at one, four and 24 hours. Protein attachment peaked within one
hour of incubation and the maximum binding efficiency was achieved
with an initial droplet of 1000 ng. We showed that after 24 hours
one-fifth of the initial Fn coating remained on the substrates,
and this resulted in a significant, three-, four-, and sevenfold
increase in dermal fibroblast attachment strength compared to uncoated controls
at one, four and 24 hours, respectively.
Platelet-derived growth factor (PDGF) is known
to stimulate osteoblast or osteoprogenitor cell activity. We investigated
the effect of locally applied PDGF from poly- These results indicate that local application of PDGF from biodegradable
PDLLA-coated implants significantly accelerates fracture healing
in experimental animals. Further development may help fracture healing
in the clinical situation.
The Norwegian Arthroplasty Register has shown that several designs of uncemented femoral stems give good or excellent survivorship. The overall findings for uncemented total hip replacement however, have been disappointing because of poor results with the use of metal-backed acetabular components. In this study, we exclusively investigated the medium-to long-term performance of primary uncemented metal-backed acetabular components. A total of 9113 primary uncemented acetabular components were implanted in 7937 patients between 1987 and 2007. These were included in a prospective, population-based observational study. All the implants were modular and metal-backed with ultra-high-molecular-weight polyethylene liners. The femoral heads were made of stainless steel, cobalt-chrome (CoCr) alloy or alumina ceramic. In all, seven different designs of acetabular component were evaluated by the Kaplan-Meier survivorship method and Cox regression analysis. Most acetabular components performed well up to seven years. When the endpoint was revision of the acetabular component because of aseptic loosening, the survival ranged between 87% and 100% at ten years. However, when the endpoint was revision for any reason, the survival estimates were 81% to 92% for the same implants at ten years. Aseptic loosening, wear, osteolysis and dislocation were the main reasons for the relatively poor overall performance of the acetabular components. Prostheses with alumina heads performed slightly better than those with stainless steel or CoCr alloy in subgroups. Whereas most acetabular components performed well at seven years, the survivorship declined with longer follow-up. Fixation was generally good. None of the metal-backed uncemented acetabular components with ultra-high-molecular-weight polyethylene liners in our study had satisfactory long-term results because of high rates of wear, osteolysis, aseptic loosening and dislocation.
We used demineralised bone matrix (DBM) to augment re-attachment of tendon to a metal prosthesis in an A significant increase of 23.5% was observed in functional weight-bearing at six weeks in the DBM-augmented group compared with non-augmented controls (p = 0.004). By 12 weeks augmentation with DBM resulted in regeneration of a more direct-type enthesis, with regions of fibrocartilage, mineralised fibrocartilage and bone. In the controls the interface was predominantly indirect, with the tendon attached to the bone graft-hydroxyapatite base plate by perforating collagen fibres.
Carbonate-substituted hydroxyapatite (CHA) is more osteoconductive and more resorbable than hydroxyapatite (HA), but the underlying mode of its action is unclear. We hypothesised that increased resorption of the ceramic by osteoclasts might subsequently upregulate osteoblasts by a coupling mechanism, and sought to test this in a large animal model. Defects were created in both the lateral femoral condyles of 12 adult sheep. Six were implanted with CHA granules bilaterally, and six with HA. Six of the animals in each group received the bisphosphonate zoledronate (0.05 mg/kg), which inhibits the function of osteoclasts, intra-operatively. After six weeks bony ingrowth was greater in the CHA implants than in HA, but not in the animals given zoledronate. Functional osteoclasts are necessary for the enhanced osteoconduction seen in CHA compared with HA.
Bone surface strains were measured in cadaver femora during loading prior to and after resurfacing of the hip and total hip replacement using an uncemented, tapered femoral component. In vitro loading simulated the single-leg stance phase during walking. Strains were measured on the medial and the lateral sides of the proximal aspect and the mid-diaphysis of the femur. Bone surface strains following femoral resurfacing were similar to those in the native femur, except for proximal shear strains, which were significantly less than those in the native femur. Proximomedial strains following total hip replacement were significantly less than those in the native and the resurfaced femur. These results are consistent with previous clinical evidence of bone loss after total hip replacement, and provide support for claims of bone preservation after resurfacing arthroplasty of the hip.
We have managed 27 patients (16 women and 11 men) with a mean age of 68.4 years (50 to 84), with failed total hip replacement and severe proximal femoral bone loss by revision using a distal fix/proximal wrap prosthesis. The mean follow-up was for 55.3 months (25 to 126). The mean number of previous operations was 2.2 (1 to 4). The mean Oxford hip score decreased from 46.2 (38 to 60) to 28.5 (17 to 42) (paired t-test, p <
0.001) and the mean Harris Hip score increased from 30.4 (3 to 57.7) to 71.7 (44 to 99.7) (paired t-test, p <
0.001). There were two dislocations, and in three patients we failed to eradicate previous infection. None required revision of the femoral stem. This technique allows instant distal fixation while promoting biological integration and restoration of bone stock. In the short term, the functional outcome is encouraging and the complication rates acceptable in this difficult group of patients.
Despite advances in the prevention and treatment of osteoporotic fractures, their prevalence continues to increase. Their operative treatment remains a challenge for the surgeon, often with unpredictable outcomes. This review highlights the current aspects of management of these fractures and focuses on advances in implant design and surgical technique.
This study describes 146 primary total knee replacements, either fully or partially coated with hydroxyapatite of which 74 knees in 68 patients were available for clinical and radiological assessment at a mean of 11.2 years (10 to 15). The global failure rate was 1.37% and survival rate with mechanical failure as the end-point was 98.14%. Radiological assessment indicated intimate contact between bone and the hydroxyapatite coating. Over time the hydroxyapatite coating appears to encourage filling of interface gaps remaining after surgery. Our results compare favourably with those of series describing cemented or porous-coated knee replacements, and suggest that fixation with hydroxyapatite is a reliable option in primary total knee replacement.
When performing the Scandinavian Total Ankle Replacement (STAR), the positioning of the talar component and the selection of mobile-bearing thickness are critical. A biomechanical experiment was undertaken to establish the effects of these variables on the range of movement (ROM) of the ankle. Six cadaver ankles containing a specially-modified STAR prosthesis were subjected to ROM determination, under weight-bearing conditions, while monitoring the strain in the peri-ankle ligaments. Each specimen was tested with the talar component positions in neutral, as well as 3 and 6 mm of anterior and posterior displacement. The sequence was repeated with an anatomical bearing thickness, as well as at 2 mm reduced and increased thicknesses. The movement limits were defined as 10% strain in any ligament, bearing lift-off from the talar component or limitations of the hardware. Both anterior talar component displacement and bearing thickness reduction caused a decrease in plantar flexion, which was associated with bearing lift-off. With increased bearing thickness, posterior displacement of the talar component decreased plantar flexion, whereas anterior displacement decreased dorsiflexion.
We investigated the effect of stimulation with a pulsed electromagnetic field on the osseointegration of hydroxyapatite in cortical bone in rabbits. Implants were inserted into femoral cortical bone and were stimulated for six hours per day for three weeks. Electromagnetic stimulation improved osseointegration of hydroxyapatite compared with animals which did not receive this treatment in terms of direct contact with the bone, the maturity of the bone and mechanical fixation. The highest values of maximum push-out force (Fmax) and ultimate shear strength (σu) were observed in the treated group and differed significantly from those of the control group at three weeks (Fmax; p <
0.0001; σu, p <
0.0005).
The Morscher-Spotorno (MS-30) femoral stem is a stainless-steel, straight, three-dimensionally tapered, collarless implant for cemented fixation in total hip replacement. We report the results at ten years of a consecutive series of 124 total hip replacements in 121 patients with the matt-surfaced MS-30 stem and an alumina ceramic head of 28-mm diameter. All the stems were fixed with Palacos bone cement with gentamicin using a modern cementing technique. They were combined with an uncemented, press-fit cup. The mean period of observation was 10.2 years (8.3 to 12.1) and no patient was lost to follow-up. Twenty-seven patients (22%) died with the implant None of the stems or cups had been revised. The Harris hip score was excellent or good in 97% (85 hips) and moderate in 3% (three hips). Radiologically, six hips (6.8%) had osteolysis adjacent to the stem, mostly in Gruen zone 7. Twenty (22.7%) showed one or more radiolucent lines. Twenty-two stems (25%) had subsided by 2 mm to 5 mm. In these cases two showed osteolysis (9.1%) with subsidence and four without (6.1%). Radiolucent lines were seen in seven with migration (31.8%) and in 13 without (19.7%). No infections and no acetabular osteolysis were observed. The clinical results were excellent with survivorship after ten years of 100% and only a slightly statistically non-significant higher rate of osteolysis and radiolucency in cases of subsidence.
Autologous chondrocyte implantation (ACI) is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes. We have performed a prospective, randomised comparison of ACI-C and MACI for the treatment of symptomatic chondral defects of the knee in 91 patients, of whom 44 received ACI-C and 47 MACI grafts. Both treatments resulted in improvement of the clinical score after one year. The mean modified Cincinnati knee score increased by 17.6 in the ACI-C group and 19.6 in the MACI group (p = 0.32). Arthroscopic assessments performed after one year showed a good to excellent International Cartilage Repair Society score in 79.2% of ACI-C and 66.6% of MACI grafts. Hyaline-like cartilage or hyaline-like cartilage with fibrocartilage was found in the biopsies of 43.9% of the ACI-C and 36.4% of the MACI grafts after one year. The rate of hypertrophy of the graft was 9% (4 of 44) in the ACI-C group and 6% (3 of 47) in the MACI group. The frequency of re-operation was 9% in each group. We conclude that the clinical, arthroscopic and histological outcomes are comparable for both ACI-C and MACI. While MACI is technically attractive, further long-term studies are required before the technique is widely adopted.