We studied 52 patients, each with a lumbosacral
Introduction. The
Objectives. Up to 10% of fractures result in undesirable outcomes, for which female sex is a risk factor. Cellular sex differences have been implicated in these different healing processes. Better understanding of the mechanisms underlying bone healing and sex differences in this process is key to improved clinical outcomes. This study utilized a macrophage–mesenchymal stem cell (MSC) coculture system to determine: 1) the precise timing of proinflammatory (M1) to anti-inflammatory (M2) macrophage
Aims. Some patients presenting with hip pain and instability and underlying acetabular dysplasia (AD) do not experience resolution of symptoms after surgical management. Hip-spine syndrome is a possible underlying cause. We hypothesized that there is a higher frequency of radiological spine anomalies in patients with AD. We also assessed the relationship between radiological severity of AD and frequency of spine anomalies. Methods. In a retrospective analysis of registry data, 122 hips in 122 patients who presented with hip pain and and a final diagnosis of AD were studied. Two observers analyzed hip and spine variables using standard radiographs to assess AD. The frequency of lumbosacral
Aims. Bone metastasis ultimately occurs due to a complex multistep process, during which the interactions between cancer cells and bone microenvironment play important roles. Prior to colonization of the bone, cancer cells must succeed through a series of steps that will allow them to gain migratory and invasive properties; epithelial-to-mesenchymal
The coronavirus disease 2019 (COVID-19) pandemic has led to unprecedented challenges to healthcare systems worldwide. Orthopaedic departments have adopted business continuity models and guidelines for essential and non-essential surgeries to preserve hospital resources as well as protect patients and staff. These guidelines broadly encompass reduction of ambulatory care with a move towards telemedicine, redeployment of orthopaedic surgeons/residents to the frontline battle against COVID-19, continuation of education and research through web-based means, and cancellation of non-essential elective procedures. However, if containment of COVID-19 community spread is achieved, resumption of elective orthopaedic procedures and
BACKGROUND. Diffuse noxious inhibitory control (DNIC) is impaired in people with chronic pain such as knee osteoarthritis (KOA), which may predict the risk of acute-to-chronic pain
Bone tendon junction (BTJ) healing after injury is often slow, without restoration of fibrocartilage
Due to demographic changes patients >
80yrs (octogenarians) are a rapidly growing group in total hip arthroplasty (THA). Stem design, choice, sizing and surgical insertion are more important in these patients as complications such as fractures are critical. Age and gender driven differences regarding canal shape (flare index, CFI), cortical wall thickness (WT) and bone mineral density (BMD) have been studied before only in isolation. Using CT, this study aims to investigate these parameters in combination and in 3D with a focus on the very elderly, identifying the regions critical for THA. High-resolution CT-scans (1mm slices) of 168 femora (M/F=100/68) were analyzed in 3D (Mimics V12). Flaring indices were based on the dimensions measured 20mm proximal to the lesser trochanter (LT) and 60mm distal to LT: intramedullary surface area (3D-CFI), frontal/lateral planes (2D-CFI) and flaring of the 4 sides medial (med), lateral (lat), anterior (ant), posterior (post) (1D-CFI). WT was calculated subtracting periosteal and endosteal dimensions and BMD was measured in Hounsfield Units (HU). An octogenarian group (80+: n=117, mean age 84yrs [80–105]) was compared to a typical THA age group (80−: n=51, mean age 68yrs [39–79]). Age and gender had significant effects on several parameters but at different levels, e.g. 2D frontal CFI was more influenced by the small age difference (80+ vs 80−=12%, p<
0.01) than gender (F vs M=2%). However, regarding lateral canal width, gender (F vs M=7%, p<
0.01), was more influential than age (80+ vs 80−=3%). The age-related changes on the shape occurred in 3D (3D-CFI 80+ vs 80−=23%, p<
0.01), but were asymmetrical between the 4 sides (e.g. 1D-CFI 80+ vs 80−: med=11%, p<
0.01) vs ant=27%, p<
0.01). Age and gender did not only effect shape, but also cortical WT, e.g. proximally octogenarian females had 35% less WT than the typical THA age group while males only had 14% lower WT (p<
0.01). Age, gender and shape asymmetry was also reflected in BMD distribution. on the medial side, the BMD gender difference in the octogenarians was small (=1%, p=0.61) but high on the anterior side (12%, p<
0.01). The most critical configurations for the octogenarians were found proximally on the posterior side with the lowest WT, lowest BMD and largest gender difference. The complex
Summary Statement. Paraspinal muscle contain higher proportion of slow-twich fibers. The fixation of the rat tail induced
Background: It has been suggested that the
Anterior cruciate ligament reconstruction is a common procedure performed by orthopaedic surgeons. The procedure continues to evolve, with a trend towards more accurate reconstruction of the pre-existing anatomy. Single bundle reconstruction has been the gold standard, with good to excellent results returning many athletes to their chosen sports. Persisting functional instability and late degenerative changes are well described, encouraging several centres to attempt to improve upon the single bundle technique. This is a technical paper examining the first 15 cases in a single surgeon series. Technical challenges unique to double bundle reconstruction will be discussed with suggestions on how to minimise problems. Tourniquet time, early complications and KT1000 measures will be presented. The technical requirements of anatomic double bundle ACL reconstruction fall within the skill set of a competent arthroscopist. The
Introduction. It has been suggested that the
We present the first 12 consecutive patients, undergoing elective paediatric limb reconstruction with an external fixator, for the 12-month period October 2020-October 2021. This is a single surgeon series for a newly appointed Consultant with limited previous experience. Arrangements were made for mentoring by a senior surgeon recently retired from the NHS but still active in private practice. The average age of patients was 10.5years at the time of frame application (5—15 years). Four frames in three patients were for Blount's; two for sequelae of NF1; two for posteromedial tibial bow with shortening, two for fibula hemimelia; one congenital short femur, one for sequelae of neonatal sepsis and one for bone loss following tumour resection.Introduction
Materials and Methods
This is an outcome study of the use of plate fixation for treatment of comminuted fractures of the distal third of tibia to determine prognostic factors such as age, sex, type of fractures, soft tissue injury and type of implant on healing. Since 1999, a single surgeon (VP) has performed minimally invasive fixation in 18 patients for complex
There were 70000 people admitted to hospital with fractured hips in 2007 and the incidence is rising by 2% each year. Hip fractures represent significant morbidity and mortality to patients and cost the NHS £1.8 billion annually. In 2008 the British Orthopaedic Association Standards for Trauma (BOAST) issued a 14-point guideline to be followed for the management of hip fractures. The aim was to improve secondary prevention of osteoporosis, reduce the falls risk and further fractures. This aimed to provide better care to improve the outcomes for patients and reduce the burden of hip fractures on society. The aim of the audit was to see if the BOAST guidelines are met before and after the
Introduction. Femoral heads made from zirconia-toughened alumina (ZTA) are the most advanced bioceramic available for total hip arthroplasty. ZTA's superior mechanical properties result from the polymorphic transformation of its zirconia (ZrO. 2. ) phase in the presence of a propagating crack. In vitro derived activation energies predict that several human lifetimes are needed to reach a state of significant transformation;. 1. but in vivo confirmation of material stability is still lacking. This investigation determined if
Background: 70% of Breast Cancer patients develop metastatic bone deposits, predominantly spinal metasases. Adult Mesenchymal Stem Cells (MSCs) are multiprogenitor stem cells found within the bone marow which have the ability to self renew and differentiate into multiple cell types. MSCs home specifically to tumour sites, highlighting their potential as delivery vehicles for therapeutic agents. However studies show they may also increase tumour metastatic potential. Aims: The aim of this study was to investigate interactions between MSCs and breast cancer cells to further elucidate their role in the tumour microenvironment and hence understand factors involved in stimulating the formation of bone metastases. Methods: MSCs harvested from the iliac crest of healthy volunteers were grown for collection of conditioned medium (CM), containing all factors secreted by the cells. Breast cancer cell lines (T47D, SK-BR3) were then cultured in MSC CM +/− antibodies to TGFβ, VEGF, MCP-1 and CCL5 for 72hrs. Cell proliferation was assessed using an Apoglow. ®. assay and RNA harvested for analysis of changes in Epithelial Mesenchymal
Transitional vertebrae (TV) may be one of the risk factors for lumbar disc herniation. It is not clear, however, whether the presence of TV can affect the development of nerve-root symptoms. Our aim was to clarify this relationship. A total of 501 patients with lumbar degenerative disease and nerve-root symptoms was studied in respect of their level and the presence of TV. As a control group, 508 patients without low back pain or nerve-root symptoms were studied to establish the incidence of TV. In patients with disc herniation, the incidence was statistically higher and the mean age lower in patients with TV than in those without. In most patients, the symptomatic disc level was just above the TV. Similarly, in those with stenosis of the spinal canal without spondylolisthesis, the symptomatic disc level was most commonly just above the TV.
Background. 70% of breast cancer patients develop metastatic bone deposits, predominantly spinal metasases. Adult Mesenchymal Stem Cells (MSCs) are multiprogenitor stem cells found within the bone marow which have the ability to self-renew and differentiate into multiple cell types. MSCs home specifically to tumour sites, highlighting their potential as delivery vehicles for therapeutic agents. However studies show they may also increase tumour metastatic potential. Aim. To investigate interactions between MSCs and breast cancer cells to further elucidate their role in the tumour microenvironment and hence understand factors involved in stimulating the formation of bone metastases. Methods. MSCs harvested from the iliac crest of healthy volunteers were grown for collection of conditioned medium (CM), containing all factors secreted by the cells. Breast cancer cell lines (T47D, SK-BR-3, MDA-MB-231) were then cultured in MSC CM +/− antibodies to TGFβ, VEGF, MCP-1 and CCL5 for 72hrs. Cell proliferation was assessed using an Apoglow. (r). assay and RNA harvested for analysis of changes in Epithelial Mesenchymal
Background. 70% of Breast Cancer patients develop metastatic bone deposits, predominantly spinal metasases. Adult Mesenchymal Stem Cells (MSCs) are multiprogenitor stem cells found within the bone marow which have the ability to self renew and differentiate into multiple cell types. MSCs home specifically to tumour sites, highlighting their potential as delivery vehicles for therapeutic agents. However studies show they may also increase tumour metastatic potential. Aims. The aim of this study was to investigate interactions between MSCs and breast cancer cells to further elucidate their role in the tumour microenvironment and hence understand factors involved in stimulating the formation of bone metastases. Methods. MSCs harvested from the iliac crest of healthy volunteers were grown for collection of conditioned medium (CM), containing all factors secreted by the cells. Breast cancer cell lines (T47D, SK-BR-3, MDA-MB-231) were then cultured in MSC CM +/− antibodies to TGFβ, VEGF, MCP-1 and CCL5 for 72hrs. Cell proliferation was assessed using an Apoglow(r) assay and RNA harvested for analysis of changes in Epithelial Mesenchymal
Most people experience low back pain (LBP) at least once in their lifetime. A minority goes on to develop persistent LBP causing significant socioeconomic costs. Aim of this study was to identify factors that influence the progression of acute to persistent LBP at an early stage (Hilfiker et al. 2007). Prospective inception cohort study of patients attending a health practitioner for their first episode of acute LBP or recurrent LBP after a pain free period of at least six months. Patients were assessed at baseline addressing occupational and psychological factors as well as pain, disability, quality of life and physical activity, and followed up over six months. Baseline and follow-up questionnaires were based on the recommendations of the Multinational Musculoskeletal Inception Cohort Study (MMICS) Statement (Pincus et al. 2008). Variables were combined to the three indices ‘working condition’, ‘depression and maladaptive cognitions’ and ‘pain and quality of life’. The index ‘depression and maladaptive cognitions’ comprising of depression, somatisation, a resigned attitude towards the job, fear-avoidance, catastrophizing and negative expectations on return to work was found to be a significant baseline predictor for persistent LBP up to six months (OR 5.1; 95%CI 1.04–25.1). The diagnostic accuracy of the predictor model had a sensitivity of 0.54 and a specificity of 0.90. Positive likelihood ratio was moderate with 5.3, negative likelihood ratio 0.5. Overall predictive accuracy of the model was 81%. The area under the curve in receiver operating characteristic (ROC) analysis of the index was 0.78 (CI95% 0.65–0.92), demonstrating a satisfactory quality of discrimination. Psychological factors in patients with acute LBP in a primary care setting correlated with a progression to persistent LBP up to six months. The benefit of including factors such as ‘depression and maladaptive cognition’ in screening tools is that these factors can be addressed in primary and secondary prevention.
The purpose of this study was to devise a simple
but reliable radiological method of identifying a lumbosacral transitional
vertebra (LSTV) with a solid bony bridge on sagittal MRI, which
could then be applied to a lateral radiograph. The vertical mid-vertebral angle (VMVA) and the vertical anterior
vertebral angle (VAVA) of the three most caudal segments of the
lumbar spine were measured on MRI and/or on a lateral radiograph
in 92 patients with a LSTV and 94 controls, and the differences
per segment (Diff-VMVA and Diff-VAVA) were calculated. The Diff-VMVA
of the two most caudal vertebrae was significantly higher in the
control group (25° ( Using this simple method (Diff-VMVA ≤ +10°), solid bony bridging
of the posterior elements of a LSTV, and therefore the first adjacent
mobile segment, can be easily identified without the need for additional
imaging. Cite this article:
Aims. To investigate the impact of consecutive perioperative care
Aims. Although lumbosacral
Introduction. Lumbosacral
Our unit historically performed total hip replacement (THR) through either posterior or anterolateral approaches. In November 2020 a group of 5 consultants
Intra-Discal Vacuum Phenomenon (IDVP) represents an intradiscal nitrogen gas accumulation where a cavity opens in a supine position, lowering intra-discal pressure and generating a bubble. IDVP has been observed in up to 20% of elderly patients and reported in almost 50% of chronic LBP patients. With a highly accurate detection on CT, its significance lacks clarity and consideration within normative data. IDVP occurs with patterns of lumbar and/or lumbopelvic morphology and associated diagnoses. Over-60s population based sample of 2020 unrelated CT abdomen scans without acute spinal presentations, with sagittal reconstructions, inclusive of T12 to femoral heads, were analyzed for IDVP and pelvic incidence (PI). Subjects with diagnostic morphological associations of the lumbar spine, including previous fracture, autofusion,
The June 2023 Spine Roundup. 360. looks at: Characteristics and comparative study of thoracolumbar spine injury and dislocation fracture due to tertiary trauma; Sublingual sufentanil for postoperative pain management after lumbar spinal fusion surgery; Minimally invasive bipolar technique for adult neuromuscular scoliosis; Predictive factors for degenerative lumbar spinal stenosis; Lumbosacral
Dysmorphic pelves are a known risk factor for malpositioned iliosacral screws. Improved understanding of pelvic morphology will minimise the risk of screw misplacement, neurovascular injuries and failed fixation. Existing classifications for sacral anatomy are complex and impractical for clinical use. We propose a CT-based classification using variations in pelvic anatomy to predict the availability of transosseous corridors across the sacrum. The classification aims to refine surgical planning which may reduce the risk of surgical complications. The authors postulated 4 types of pelves. The “superior most point of the sacroiliac joint” (sSIJ) typically corresponds with the mid-lower half of the L5 vertebral body. Hence, “the anterior cortex of L5” (L5. a. ) was divided to reference 3 distinct pelvic groups. A 4. th. group is required to represent pelves with a lumbosacral
Abstract. Patellofemoral Arthroplasty (PFA) is an alternative to TKA for patellofemoral osteoarthritis that preserves tibiofemoral compartments. It is unknown how implant positioning affects biomechanics, especially regarding the patella. This study analysed biomechanical effects of femoral and patellar component position, hypothesising femoral positioning is more important. Nine cadaveric knees were studied using a repeated-measures protocol. Knees were tested intact, then after PFA implanted in various positions: neutral (as-planned), patellar over/understuffing (±2mm), patellar tilt, patellar flexion, femoral rotation, and femoral tilt (all ±6°). Arthroplasties were implemented with CT-designed patient-specific instrumentation. Anterior femoral cuts referenced Whiteside's line and all femoral positions ensured smooth condyle-to-component
Microdiscectomy is the most commonly performed spine surgery in the world. Due to its technical simplicity and low complication rate, this was the first spine surgical procedure
Aims. The cemented Oxford unicompartmental knee arthroplasty (OUKA) features two variants: single and twin peg OUKA. The purpose of this study was to assess the stability of both variants in a worst-case scenario of bone defects and suboptimal cementation. Methods. Single and twin pegs were implanted randomly allocated in 12 pairs of human fresh-frozen femora. We generated 5° bone defects at the posterior condyle. Relative movement was simulated using a servohydraulic pulser, and analyzed at 70°/115° knee flexion. Relative movement was surveyed at seven points of measurement on implant and bone, using an optic system. Results. At the main fixation zone, the twin peg shows less relative movement at 70°/115°. At the
Abstract. Objectives. Neonatal motor development
Aims. Adenosine, lidocaine, and Mg. 2+. (ALM) therapy exerts differential immuno-inflammatory responses in males and females early after anterior cruciate ligament (ACL) reconstruction (ACLR). Our aim was to investigate sex-specific effects of ALM therapy on joint tissue repair and recovery 28 days after surgery. Methods. Male (n = 21) and female (n = 21) adult Sprague-Dawley rats were randomly divided into ALM or Saline control treatment groups. Three days after ACL rupture, animals underwent ACLR. An ALM or saline intravenous infusion was commenced prior to skin incision, and continued for one hour. An intra-articular bolus of ALM or saline was also administered prior to skin closure. Animals were monitored to 28 days, and joint function, pain, inflammatory markers, histopathology, and tissue repair markers were assessed. Results. Despite comparable knee function, ALM-treated males had reduced systemic inflammation, synovial fluid angiogenic and pro-inflammatory mediators, synovitis, and fat pad fibrotic changes, compared to controls. Within the ACL graft, ALM-treated males had increased expression of tissue repair markers, decreased inflammation, increased collagen organization, and improved graft-bone healing. In contrast to males, females had no evidence of persistent systemic inflammation. Compared to controls, ALM-treated females had improved knee extension, gait biomechanics, and elevated synovial macrophage inflammatory protein-1 alpha (MIP-1α). Within the ACL graft, ALM-treated females had decreased inflammation, increased collagen organization, and improved graft-bone healing. In articular cartilage of ALM-treated animals, matrix metalloproteinase (MMP)-13 expression was blunted in males, while in females repair markers were increased. Conclusion. At 28 days, ALM therapy reduces inflammation, augments tissue repair patterns, and improves joint function in a sex-specific manner. The study supports
Abstract. Objectives. The patella tendon (PT) is commonly used as a graft material for anterior cruciate ligament reconstruction (ACLR). The function of the graft is to restore the mechanical behaviour of the knee joint. Therefore, it is essential that a robust methodology be developed for the mechanical testing of the PT, as well as for the tissue engineered grafts derived from this tissue. Our objectives were to (1) survey the literature, in order to define the state-of-the-art in mechanical testing of the PT, highlighting the most commonly used testing protocols, and (2) conduct validation studies using porcine PT to compare the mechanical measurements obtained using different methodological approaches. Methods. A PubMed search was performed using a boolean search term to identify publications consisting of PT tensile testing, and limited to records published in the past ten years (2010–2020). This returned a total of 143 publications. A meta-analysis was undertaken to quantify the frequency of commonly used protocol variations (pre-conditioning regime, strain rates, maximum strain, etc.). Validation studies were performed on porcine PT (n=4) using Instron tensile testing apparatus to examine the effect of preconditioning on low-strain (toe-region) mechanical properties. Results. Ramp-to-failure testing was found to be most commonly performed (included in over 90 % of publications), followed by stress relaxation and cyclic testing (∼25 %). Preconditioning was most commonly cyclic (27 %), involving 10–100 cycles. Validation studies show the number of cycles and duration of preconditioning, has no significant effect on toe region
Imaging can provide valuable information about the function of tissues and organs. The capacity for detecting and measuring imaging biomarkers of biological activities, allows for a better understanding of the pathophysiology of any process in the human body, including the musculoskeletal system. This is of particular importance in oncologic, metabolic and rheumatologic diseases, but not limited to these. In the domain of the musculoskeletal system, functional imaging also means to be able to address biomechanical evaluations. Weight-bearing imaging and dynamic studies have a prominent role. All imaging techniques (X-rays, CT, MR, ultrasound) are in demand, and offer different applications, specific equipment and novel methods for addressing this. Functional imaging is also essential to drive minimally invasive treatments – i.e. interventional radiology, and new treatment approaches move together with the advances on imaging guidance methods. On both the diagnostic and the interventional side, the increasing availability of dedicated equipment and the development of specific imaging methods and protocols greatly helps the
The anterior cruciate ligament (ACL) is the connective tissue located at the end of long bones providing stability to the knee joint. After tear or rupture clinical reconstruction of the tissue remains a challenge due to the particular mechanical properties required for proper functioning of the tissue. The outstanding mechanical properties of the ACL are characterized by a viscoelastic behavior responsible of the dissipation of the loads that are transmitted to the bone. These mechanical properties are the result of a very specialized graded extracellular matrix that
Tryfonidou leads the Horizon 2020 consortium (iPSpine; 2019–2023) bringing a transdisciplinary team of 21 partners together to address the challenges and bottlenecks of iPS-based advanced therapies towards their
While pre-soaking grafts in vancomycin has demonstrated to be effective in observational studies for anterior cruciate ligament reconstruction (ACLR) infection prevention, the economic benefit of the technique is uncertain. The primary aim of this study was to determine the cost-effectiveness of vancomycin pre-soaking during primary ACLR to prevent post-operative joint infections. The secondary aims of the study were to establish the breakeven cost-effectiveness threshold of the technique. A Markov model was used to determine cost effectiveness and the incremental cost effectiveness ratio of additional vancomycin pre-soaking compared to intravenous antibiotic prophylaxis alone. A repeated meta-analysis of nine cohort studies (Level III evidence) was completed to determine the odds ratio of infection with vancomycin pre-soaking compared to intravenous antibiotics alone. Estimated costs and
Aims. Time to treatment initiation (TTI) is generally defined as the time from the histological diagnosis of malignancy to the initiation of first definitive treatment. There is no consensus on the impact of TTI on the overall survival in patients with a soft-tissue sarcoma. The purpose of this study was to determine if an increased TTI is associated with overall survival in patients with a soft-tissue sarcoma, and to identify the factors associated with a prolonged TTI. Methods. We identified 23,786 patients from the National Cancer Database who had undergone definitive surgery between 2004 and 2015 for a localized high-grade soft-tissue sarcoma of the limbs or trunk. A Cox proportional hazards model was used to examine the relationship between a number of factors and overall survival. We calculated the incidence rate ratio (IRR) using negative binomial regression models to identify the factors that affected TTI. Results. Patients in whom the time to treatment initiation was prolonged had poorer overall survival than those with a TTI of 0 to 30 days. These were: 31 to 60 days (hazard ratio (HR) 1.08, p = 0.011); 61 to 90 days (HR 1.11, p = 0.044); and 91 days (HR 1.22; p = 0.003). The restricted cubic spline showed that the hazard ratio increased substantially with a TTI longer than 50 days. Non-academic centres (vs academic centres; IRR ranging from 0.64 to 0.86; p < 0.001) had a shorter TTI. Those insured by Medicaid (vs private insurance; IRR 1.34), were uninsured (vs private insurance; IRR 1.17), or underwent a
The application of immune regenerative strategies to deal with unsolved pathologies, such as tendinopathies, is getting attention in the field of tissue engineering exploiting the innate immunomodulatory potential of stem cells [1]. In this context, Amniotic Epithelial Cells (AECs) represent an innovative immune regenerative strategy due to their teno-inductive and immunomodulatory properties [2], and because of their high paracrine activity, become a potential stem cell source for a cell-free treatment to overcome the limitations of traditional cell-based therapies. Nevertheless, these immunomodulatory mechanisms on AECs are still not fully known to date. In these studies, we explored standardized protocols [3] to better comprehend the different phenotypic behavior between epithelial AECs (eAECs) and mesenchymal AECs (mAECs), and to further produce an enhanced immunomodulatory AECs-derived secretome by exposing cells to different stimuli. Hence, in order to fulfill these aims, eAECs and mAECs at third passage were silenced for CIITA and Nrf2, respectively, to understand the role of these molecules in an inflammatory response. Furthermore, AECs at first passage were seeded under normal or GO-coated coverslips to study the effect of GO on AECs, and further exposed to LPS and/or IL17 priming to increase the anti-inflammatory paracrine activity. The obtained results demonstrated how CIITA and Nrf2 control the immune response of eAECs and mAECs, respectively, under standard or immune-activated conditions (LPS priming). Additionally, GO exposition led to a faster activation of the Epithelial-Mesenchymal
Abstract. Introduction. Mid-flexion instability may cause poor outcomes following TKA. Surgical technique, patient-specific factors, and implant design could all contribute to it, with modelling and fluoroscopy data suggesting the latter may be the root cause. However, current implants all pass the preclinical stability testing standards, making it difficult to understand the effects of implant design on instability. We hypothesized that a more physiological test, analysing functional stability across the range of knee flexion-extension, could delineate the effects of design, independent of surgical technique and patient-specific factors. Methods. Using a SIMvitro-controlled six-degree-of-freedom robot, a dynamic stability test was developed, including continuous flexion and reporting data in a trans-epicondylar axis system. 3 femoral geometries were tested: gradually reducing radius, multi-radius and single-radius, with their respective tibial inserts. 710N of compression force (body weight) was applied to the implants as they were flexed from 0–140° with three levels of anterior/posterior (AP) tibial force applied (−90N,0N,90N). Results. While in static tests, the implants performed similarly, functional stability testing revealed different paths of motion and AP laxities throughout the flexion cycle. Some designs exhibited mid-flexion instability, while others did not: the multi-radius design allowed increased AP laxity as it
Tendons mainly consist of collagen in order to withstand high tensile forces. Compared to other, high turnover tissues, cellularity and vascularity in tendons are low. Thus, the natural healing process of tendons takes long and can be problematic. In case of injury to the enthesis, the special
Complications after spinal fusion surgery are common, with implant loosening occurring in up to 50% of osteoporotic patients. Pedicle screw fixation strength reduces as a result of decreased trabecular bone density, whereas sublaminar wiring is less affected by these changes. Therefore, pedicle screw augmentation with radiopaque sublaminar wires (made with Dyneema Purity® Radiapque fibers, DSM Biomedical, Geleen, the Netherlands) may improve fixation strength. Furthermore, sublaminar tape could result in a gradual motion
Integrin α2β1 is one of the major transmembrane receptors for fibrillary collagen. In native bone we could show that the absence of this protein led to a protective effect against age-related osteoporosis. The objective of this study was to elucidate the effects of integrin α2β1 deficiency on fracture repair and its underlying mechanisms. Standardised femoral fractures were stabilised by an intramedullary nail in 12 week old female C57Bl/6J mice (wild type and integrin α2. -/-. ). After 7, 14 and 28 days mice were sacrificed. Dissected femura were subjected to µCT and histological analyses. To evaluate the biomechanical properties, 28-day-healed femura were tested in a torsional testing device. Masson goldner staining, Alizarin blue, IHC and IF staining were performed on paraffin slices. Blood serum of the animals were measured by ELISA for BMP-2. Primary osteoblasts were analysed by in/on-cell western technology and qRT-PCR. Integrin α2β1 deficient animals showed earlier
Aims. Arthroplasty surgery of the knee and hip is performed in two to three million patients annually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiotics, and implant retention (DAIR) surgery aimed at cleaning the infected prosthesis often fails, subsequently requiring invasive revision of the complete prosthetic reconstruction. Infection-specific imaging may help to guide DAIR. In this study, we evaluated a bacteria-specific hybrid tracer (. 99m. Tc-UBI. 29-41. -Cy5) and its ability to visualize the bacterial load on femoral implants using clinical-grade image guidance methods. Methods. 99m. Tc-UBI. 29-41. -Cy5 specificity for Stapylococcus aureus was assessed in vitro using fluorescence confocal imaging. Topical administration was used to highlight the location of S. aureus cultured on femoral prostheses using fluorescence imaging and freehand single photon emission CT (fhSPECT) scans. Gamma counting and fhSPECT were used to quantify the bacterial load and monitor cleaning with chlorhexidine. Microbiological culturing helped to relate the imaging findings with the number of (remaining) bacteria. Results. Bacteria could be effectively stained in vitro and on prostheses, irrespective of the presence of biofilm. Infected prostheses revealed bacterial presence on the
To detect early signs of infection infrared thermography has been suggested to provide quantitative information. Our vision is to invent a pin site infection thermographic surveillance tool for patients at home. A preliminary step to this goal is the aim of this study, to automate the process of locating the pin and detecting the pin sites in thermal images efficiently, exactly, and reliably for extracting pin site temperatures. A total of 1708 pin sites was investigated with Thermography and augmented by 9 different methods in to totally 10.409 images. The dataset was divided into a training set (n=8325), a validation set (n=1040), and a test set (n=1044) of images. The Pin Detection Model (PDM) was developed as follows: A You Only Look Once (YOLOv5) based object detection model with a Complete Detection Intersection over Union (CDIoU), it was pre-trained and finetuned by the through transfer learning. The basic performance of the YOLOv5 with CDIoU model was compared with other conventional models (FCOS and YOLOv4) for deep and
Variations in pelvic anatomy are a major risk factor for misplaced percutaneous sacroiliac screws used to treat unstable posterior pelvic ring injuries. A better understanding of pelvic morphology improves preoperative planning and therefore minimises the risk of malpositioned screws, neurological or vascular injuries, failed fixation or malreduction. Hence a classification system which identifies the clinically important anatomical variations of the sacrum would improve communication among pelvic surgeons and inform treatment strategy. 300 Pelvic CT scans from skeletally mature trauma patients that did not have pre-existing posterior pelvic pathology were identified. Axial and coronal transosseous corridor widths at both S1 and S2 were recorded. Additionally, the S1 lateral mass angle were also calculated. Pelvises were classified based upon the sacroiliac joint (SIJ) height using the midpoint of the anterior cortex of L5 as a reference point. Four distinct types could be identified:. Type-A – SIJ height is above the midpoint of the anterior cortex of the L5 vertebra. Type-B – SIJ height is between the midpoint and the lowest point of the anterior cortex of the L5 vertebra. Type-C – SIJ height is below the lowest point of the anterior cortex of the L5 vertebra. Type-D – a subgroup for those with a lumbosacral
The presence of hip osteoarthritis is associated with abnormal spinopelvic characteristics. This study aims to determine whether the pre-operative, pathological spinopelvic characteristics “normalize” at 1-year post-THA. This is a prospective, longitudinal, case-control matched cohort study. Forty-seven patients underwent pre- and post- (at one-year) THA assessments. This group was matched (age, sex, BMI) with 47 controls/volunteers with well-functioning hips. All participants underwent clinical and radiographic assessments including lateral radiographs in standing, upright-seated and deep-flexed-seated positions. Spinopelvic characteristics included change in lumbar lordosis (ΔLL), pelvic tilt (ΔPT) and hip flexion (pelvic-femoral angle, ΔPFA) when moving from the standing to each of the seated positions. Spinopelvic hypermobility was defined as ΔPT>30° between standing and upright-seated positions. Pre-THA, patients illustrated less hip flexion (ΔPFA −54.8°±17.1° vs. −68.5°± 9.5°, p<0.001), greater pelvic tilt (ΔPT 22.0°±13.5° vs. 12.7°±8.1°, p<0.001) and greater lumbar movements (ΔLL −22.7°±15.5° vs. −15.4°±10.9°, p=0.015)
According to the latest report from the German Arthroplasty Registry, aseptic loosening is the primary cause of implant failure following primary hip arthroplasty. Osteolysis of the proximal femur due to the stress-shielding of the bone by the implant causes loss of fixation of the proximal femoral stem, while the distal stem remains fixed. Removing a fixed stem is a challenging process. Current removal methods rely on manual tools such as chisels, burrs, osteotomes, drills and mills, which pose the risk of bone fracture and cortical perforation. Others such as ultrasound and laser, generate temperatures that could cause thermal injury to the surrounding tissues and bone. It is crucial to develop techniques that preserve the host bone, as its quality after implant removal affects the outcome of a revision surgery. A gentler removal method based on the transcutaneous heating of the implant by induction is proposed. By reaching the glass
3D printing is rapidly being adopted by manufacturers to produce orthopaedic implants. There is a risk however of structural defects which may impact mechanical integrity. There are also no established standards to guide the design of bone-facing porous structures, meaning that manufacturers may employ different approaches to this. Characterisation of these variables in final-production implants will help understanding of the impact of these on their clinical performance. We analysed 12 unused, final-production custom-made 3D printed acetabular cups that had been produced by 6 orthopaedic manufacturers. We performed high resolution micro-CT imaging of each cup to characterise the morphometric features of the porous layers: (1) the level of porosity, (2) pore size, (3) thickness of porous struts and (4) the depth of the porous layers. We then examined the internal cup structures to identify the presence of any defects and to characterise: (1) their total number, (2) volume, (3) sphericity, (4) size and (5) location. There was a variability between designs in the level of porosity (34% to 85%), pore size (0.74 to 1.87mm), strut thickness (0.28 to 0.65mm), and porous layer depth (0.57 to 11.51mm). One manufacturer printed different porous structures between the cup body and flanges; another manufacturer printed two differing porous regions within the cup body. 5 cups contained a median (range) of 90 (58–101) defects. The median defect volume was 5.17 (1.05–17.33) mm3. The median defect sphericity and size were 0.47 (0.19–0.65) and 0.64 (0.27–8.82) mm respectively. The defects were predominantly located adjacent to screw holes, within flanges and at the
In the context of regenerative medicine for the treatment of musculoskeletal pathologies mesenchymal stromal cells (MSCs) have shown good results thanks to secretion of therapeutic factors, both free and conveyed within the extracellular vesicles (EV), which in their totality constitute the “secretome”. The portfolio and biological activity of these molecules can be modulated by both in vitro and in vivo conditions, thus making the analysis of these activities very complex. A deep knowledge of the targets regulated by the secretome has become a matter of fundamental importance and a homogeneous and complete molecular characterization is still lacking in the field of applications for the musculoskeletal system. Therefore, the aim of this work was to characterize the secretome obtained from adipose-derived MSCs (ASCs), and its modulation after pre-conditioning of the ASCs. Pre-conditioning was done by culturing cells in the presence of i) high levels of IFNγ, as proposed for the production of clinical grade secretome with enhanced regenerative potential, ii) low levels of inflammatory stimuli, mimicking conditions found in the osteoarthritis (OA) synovial fluid. Furthermore, EVs ability to migrate within cartilage, chondrocyte and synoviocytes obtained from OA patients was evaluated. The data showed that more than 50 cytokines / chemokines and more than 200 EV-microRNAs are detectable at various intensity levels in ASCs secretomes. The majority of the most abundantly present molecules are involved in the remodelling of the extracellular matrix and in the homeostasis and chemotaxis of inflammatory cells including macrophages, which in OA are often characterized by an M1 inflammatory polarization, promoting their
The current study aims to find the role of Enhance Recovery Pathway (ERP) as a multidisciplinary approach aimed to expedite rapid recovery, reduce LOS, and minimize morbidity associated with Non Fusion Anterior Scoliosis Correction (NFASC) surgery. A retrospective analysis of 35 AIS patients who underwent NFASC with Lenke 1 and Lenke 5 curves with a minimum of 1 year of follow-up was done. Patient demographics, surgical details, postoperative analgesia, mobilization, length of stay (LOS), patient satisfaction survey score with respect to information and care, and 90 days complications were collected. The cohort included 34 females and 1 male with a mean age of 15.2 years at the time of surgery. There were 16 Lenke 1 and 19 Lenke 5 in the study. Mean preoperative major thoracic and thoracolumbar/lumbar Cobb's angle were 52˚±7.6˚ and 51˚±4.5˚ respectively. Average blood loss and surgical time were 102 ±6.4 ml and 168 ± 10.2 mins respectively. Average time to commencing solid food was 6.5±1.5 hrs. Average time to mobilization following surgery was 15.5± 4.3 hrs. The average duration to the stopping of the epidural was 42.5±3.5 hrs. The average dose of opioid consumption intraoperatively was 600.5±100.5 mcg of fentanyl i.v. and 12.5±4.5 mg morphine i.v. Postoperatively opioids were administered via an epidural catheter at a dose of 2 mg of morphine every 24 hours up to 2 days and an infusion of 2mcg/hr of fentanyl along with 0.12-0.15% ropivacaine. The average duration to
Title. Longitudinal Intravital Imaging to Quantify the “Race for the Surface” Between Host Immune Cell and Bacteria for Orthopaedic Implants with S. aureus Colonization in a Murine Model. Aim. To assess S. aureus vs. host cell colonization of contaminated implants vis intravital multiphoton laser scanning microscopy (IV-MLSM) in a murine model. Method. All animal experiments were approved by IACUC. A flat stainless steel or titanium L-shaped pin was contaminated with 10. 5. CFU of a red fluorescent protein (RFP) expressing strain of USA300LAC, and surgically implanted through the femur of global GFP-transgenic mice. IV-MLSM was performed at 2, 4, and 6 hours post-op. Parallel cross-sectional CFU studies were performed to quantify the bacteria load on the implant at 2,4,6,12,18 and 24 hours. Results. 1) We developed a high-fidelity reproducible IV-MLSM system to quantify S. aureus and host cell colonization of a bone implant in the mouse femur. Proper placement of all implants were confirmed with in vivo X-rays, and ex vivo photos. We empirically derive the ROI during each imaging session by aggregating the imaged volume which ranges from (636.4um × 636.4um × 151um) = 0.625 +/- 0.014 mm. 3. of bone marrow in a global GFP-transgenic mouse. 2) IV-MLSM imaging acquisition of the “race for the surface”.In vitro MPLSM images of implants partially coated with USA300LAC (RFP-MRSA) were verified by SEM image. Results from IV-MLSM of RFP-MRSA and GFP. +. host cell colonization of the contaminated implants illustrated the mutually exclusive surface coating at 3hrs, which to our knowledge is the first demonstration of “the race for the surface” between bacteria and host cells via intravital microscopy. 3) Quantifying the “race for the surface” with CFU verification of S. aureus on the implant. 3D volumetric rendering of the GFP. +. voxels and RFP+ voxels within the ROI were generated in Imaris. The voxel numbers suggeste that the fight for the surface concludes ∼3hrs post-infection, and then
Aims. Fibrinolysis plays a key
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 implant surface, imaged using scanning electron microscopy, and analyzed using Fourier-transform infrared spectroscopy. Results. Fretting was present on 88% (53/60) of the retrieved liners, and corrosion was present on 97% (58/60). Fretting was most often found on the lip of the taper at the
Abstract. Objectives. Young patients receiving metallic bone implants after surgical resection of bone cancer require implants that last into adulthood, and ideally life-long. Porous implants with similar stiffness to bone can promote bone ingrowth and thus beneficial clinical outcomes. A mechanical remodelling stimulus, strain energy density (SED), is thought to be the primary control variable of the process of bone growth into porous implants. The sequential process of bone growth needs to be taken into account to develop an accurate and validated bone remodelling algorithm, which can be employed to improve porous implant design and achieve better clinical outcomes. Methods. A bone remodelling algorithm was developed, incorporating the concept of bone connectivity (sequential growth of bone from existing bone) to make the algorithm more physiologically relevant. The algorithm includes adaptive elastic modulus based on apparent bone density, using a node-based model to simulate local remodelling variations while alleviating numerical checkerboard problems. Strain energy density (SED) incorporating stress and strain effects in all directions was used as the primary stimulus for bone remodelling. The simulations were developed to run in MATLAB interfacing with the commercial FEA software ABAQUS and Python. The algorithm was applied to predict bone ingrowth into a porous implant for comparison against data from a sheep model. Results. The accuracy of the predicted bone remodelling was verified for standard loading cases (bending, torsion) against analytical calculations. Good convergence was achieved. The algorithm predicted good bone remodelling and growth into the investigated porous implant. Using the standard algorithm without connectivity, bone started to remodel at locations unconnected to any bone, which is physiologically implausible. The implementation of bone connectivity ensures the gradual process of bone growth into the implant pores from the sides. The bone connectivity algorithm predicted that the full remodelling required more time (approximately 50% longer), which should be considered when developing post-surgical rehabilitation strategies for patients. Both algorithms with and without bone connectivity implementation converged to same final stiffness (less than 0.01% difference). Almost all nodes reached the same density value, with only a limited number of nodes (less than 1%) in
Introduction. Routine radiographs in the follow-up of circular frames is commonplace, however the effect on clinical decision making is unclear. Previous work locally has suggested that >95% of radiographs, particularly at early time points, do not affect clinical management. This study was conducted to assess the impact of a
Previous studies revealed the close relation of anxiety and low back pain. Among people with chronic low back pain, anxiety is the most commonly reported mental disorder. Thus, in the literature, there are several studies considering the anxiety as a risk factor for chronic low back pain. The authors also documented a significant differences between sexes in anxiety and quality of life due to low back pain. US National Institute of Mental Health reports that the lifetime prevalence of an anxiety disorder is 60 % higher in women than in men and that the onset, severity, clinical course, and treatment response of anxiety disorders differ significantly in women. In addition, literature has showed that women may have a worse quality of life when they have low back pain. University students may undergo an undue amount of stress, with negative outcomes in terms of academic resuşts and personal, emotional or health, consequences. Moreover, stress can be experienced at different time periods, not only during university life, but also before, during the
Introduction. Patellar crepitus and clunk are tendofemoral-related complications predominantly associated with posterior-stabilizing (PS) total knee arthroplasty (TKA) designs [1]. Contact between the quadriceps tendon and the femoral component can cause irritation, pain, and catching of soft-tissue within the intercondylar notch (ICN). While the incidence of tendofemoral-related pathologies has been documented for some primary TKA designs, literature describing revision TKA is sparse. Revision components require a larger boss resection to accommodate a constrained post-cam and stem/sleeve attachments, which elevates the entrance to the ICN, potentially increasing the risk of crepitus. The objective of this study was to evaluate tendofemoral contact in primary and revision TKA designs, including designs susceptible to crepitus, and newer designs which aim to address design features associated with crepitus. Methods. Six PS TKA designs were evaluated during deep knee bend using a computational model of the Kansas knee simulator (Figure 1). Prior work has demonstrated that tendofemoral contact predictions from this model can differentiate between TKA patients with patellar crepitus and matched controls [2]. Incidence of crepitus of up to 14% has been reported in Insall-Burstein® II and PFC® Sigma® designs [3]. These designs, in addition to PFC® Sigma® TC3 (revision component), were included in the analyses. Primary and revision components of newer generation designs (NexGen®, Attune® and Attune® Revision) were also included. Designs were evaluated in a patient model with normal Insall-Salvati ratio and a modified model with patellar tendon length reduced by two standard deviations (13mm) to assess worst-case patient anatomy. Results. During simulations with normal patellar tendon length, only PFC® Sigma® and PFC® Sigma® TC3 showed tendofemoral contact within the trochlea, and no design showed contact at the
Adverse spinopelvic characteristics (ASC) have been associated with increased dislocation risk following primary total hip arthroplasty (THA). A stiff lumbar spine, a large posterior standing tilt when standing and severe sagittal spinal deformity have been identified as key risk factors for instability. It has been reported that the rate of dislocation in patients with such ASC may be increased and some authors have recommended the use of dual mobility bearings or robotics to reduce instability to within acceptable rates (<2%). The aims of the prospective study were to 1: Describe the true incidence of ASC in patients presenting for a THA 2. Assess whether such characteristics are associated with greater symptoms pre-THA due to the concomitant dual pathology of hip and spine and 3. Describe the early term dislocation rate with the use of ≤36mm bearings. This is an IRB-approved, two-center, multi-surgeon, prospective, consecutive, cohort study of 220 patients undergoing THA through anterolateral- (n=103; 46.8%), direct anterior- (n=104; 27.3%) or posterior- approaches (n=13; 5.9%). The mean age was 63.8±12.0 years (range: 27.7-89.0 years) and the mean BMI 28.0±5.0 kg/m. 2. (range: 19.4-44.4 kg/m. 2. ). There were 44 males (47.8%) and 48 females (52.2%). The mean follow-up was 1.6±0.5 years. Overall, 54% of femoral heads was 32 mm, and 46% was 36mm. All participants underwent lateral spinopelvic radiographs in the standing and deep-flexed seated positions were taken to determine lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic-femoral angle (PFA) and pelvic incidence (PI) in both positions. Spinal stiffness was defined as lumbar flexion <20° when
Aims. The rate of dislocation when traditional single bearing implants are used in revision total hip arthroplasty (THA) has been reported to be between 8% and 10%. The use of dual mobility bearings can reduce this risk to between 0.5% and 2%. Dual mobility bearings are more expensive, and it is not clear if the additional clinical benefits constitute value for money for the payers. We aimed to estimate the cost-effectiveness of dual mobility compared with single bearings for patients undergoing revision THA. Methods. We developed a Markov model to estimate the expected cost and benefits of dual mobility compared with single bearing implants in patients undergoing revision THA. The rates of revision and further revision were calculated from the National Joint Registry of England and Wales, while rates of
Aims. Tibial plateau fractures (TPFs) are complex injuries around the knee caused by high- or low-energy trauma. In the present study, we aimed to define the distribution and frequency of TPF lines using a 3D mapping technique and analyze the rationalization of divisions employed by frequently used classifications. Methods. In total, 759 adult patients with 766 affected knees were retrospectively reviewed. The TPF fragments on CT were multiplanar reconstructed, and virtually reduced to match a 3D model of the proximal tibia. 3D heat mapping was subsequently created by graphically superimposing all fracture lines onto a tibia template. Results. The cohort included 405 (53.4%) cases with left knee injuries, 347 (45.7%) cases with right knee injuries, and seven (0.9%) cases with bilateral injuries. On mapping, the hot zones of the fracture lines were mainly concentrated around the anterior cruciate ligament insertion, posterior cruciate ligament insertion, and the inner part of the lateral condyle that extended to the junctional zone between Gerdy’s tubercle and the tibial tubercle. Moreover, the cold zones were scattered in the posteromedial fragment, superior tibiofibular syndesmosis, Gerdy’s tubercle, and tibial tubercle. TPFs with different Orthopaedic Trauma Association/AO Foundation (OTA/AO) subtypes showed peculiar characteristics. Conclusion. TPFs occurred more frequently in the lateral and intermedial column than in the medial column. Fracture lines of tibial plateau occur frequently in the
Introduction. Background: Trochanteric bursitis is a common and poorly understood complication following total hip arthroplasty (THA). The purpose of this study was to evaluate the incidence of symptomatic trochanteric bursitis and the change in hip offset among THA patients before and after the introduction of robotic assistance. Methods. Retrospective chart review of THAs performed by a single over a 3-year period between 1/5/2013 and 6/28/2016. Between 1/5/2013 and 11/11/2014 101 consecutive patients were identified that underwent manual posterior-lateral THA that utilized traditional cup positioning method based on AP Pelvis radiograph. The subsequent six-month period during a complete
Introduction. This study sought to evaluate the patient experience and short-term clinical outcomes associated with the hospital stay of patients who underwent robotic arm-assisted total knee arthroplasty (TKA). These results were compared to a cohort of patients who underwent TKA without robotic assistance performed by the same surgeon. Methods. A cohort of consecutive patients undergoing primary TKA for the diagnosis of osteoarthritis by a single fellowship trained orthopaedic surgeon over a 39-month period was identified. Patients who underwent TKA during the year this surgeon
Introduction. The aim of this study is to report the 30 day COVID-19 related morbidity and mortality of patients assessed as SARS-CoV-2 negative who underwent emergency or urgent orthopaedic surgery in the NHS during the peak of the COVID-19 pandemic. Method. A retrospective, single centre, observational cohort study of all patients undergoing surgery between 17 March 2020 and 3May 2020 was performed. Outcomes were stratified by British Orthopaedic Association COVID-19 Patient Risk Assessment Tool. Patients who were SARS-CoV-2 positive at the time of surgery were excluded. Results. Overall, 96 patients assessed as negative for SARS-CoV-2 at the time of surgery underwent 100 emergency or urgent orthopaedic procedures during the study period. Within 30 days of surgery 9.4% of patients (n = 9) were found to be SARS-CoV-2 positive by nasopharyngeal swab. The overall 30 day mortality rate across the whole cohort of patients during this period was 3% (n = 3). Of those testing positive for SARS-CoV-2 66% (n = 6) developed significant COVID-19 related complications and there was a 33% 30-day mortality rate (n = 3). Overall, the 30-day mortality in patients classified as BOA low or medium risk (n = 69) was 0%, whereas in those classified as high or very high risk (n = 27) it was 11.1%. Conclusion. Orthopaedic surgery in SARS-CoV-2 negative patients who
Introduction and Objective. Total knee arthroplasty (TKA) is a frequently and increasingly performed surgery in the treatment of disabling knee osteoarthritis. The rising number of procedures and related revisions pose an increasing economic burden on health care systems. In an attempt to lower the revision rate due to component malalignment and soft tissue imbalance in TKA, robotic assistance (RA) has been introduced in the operating theatre. The primary objective of this study is to provide the results of a theoretical, preliminary cost-effectiveness analysis of RA TKA. Materials and Methods. A Markov state-transition model was designed to model the health status of sixty-seven-year-old patients in need of TKA due to primary osteoarthritis over a twenty-year period following their knee joint replacement. Transitional probabilities and independent variables were extracted from existing literature. Patients’ state in the
Aims. Recent improvements in surgical technique and perioperative blood management after total joint replacement (TJR) have decreased rates of transfusion. However, as many surgeons
Introduction. It is well accepted that larger heads provide more stability in total hip arthroplasty. This is due to an increase in jump height providing increased resistance to subluxation. However, other implant parameters also contribute to the bearing's stability. Specifically, the liner's rim design and the centre of rotation relative to the liner's face. Both these features contribute to define the Cup Articular Arc Angle (CAAA). The CAAA describes the degree of dysplasia of the acetabular liner, and plays an important role in defining the jump height. The aim of this study was to determine the difference in jump height between bearing materials with a commonly used acetabular implant system. Methods. From 3D models of the Trinity acetabular implant system (Corin, UK), the CAAA was measured in CAD software (SolidWorks, Dassault Systems, France) for the ceramic, poly and modular dual mobility (DM) liners, for cup sizes 46mm to 64mm. The most commonly used bearing size was used in the analysis of each cup size. For the ceramic and poly liners, a 36mm bearing was used for cups 50mm and above. For the 46mm and 48mm cups, a 32mm bearing was used. The DM liners were modelled with the largest head size possible. Using a published equation, the jump height was calculated for each of the three bearing materials and each cup size. Cup inclination and anteversion were kept constant. Results. CAAA varied substantially between cup sizes and bearing materials. The mean CAAA for the ceramic, poly and DM bearings were 166°, 175° and 186°, respectively. Consequently, over the entire size range, the ceramic liners had the lowest mean jump height of 12.9mm. In comparison to the ceramic liner, there was a mean 10% increase in jump height when
Introduction and Objective. Gait variability is the amplitude of the fluctuations in the time series with respect to the mean of kinematic (e.g., joint angles) or kinetic (e.g., joint moments) measurements. Although gait variability increases with normal ageing or pathological mechanisms, such as knee osteoarthritis (OA). The purpose was to determine if a patient who underwent a total knee arthroplasty (TKA) can reduce gait variability. Materials and Methods. Twenty-five patients awaiting TKA were randomly assigned to receive either medial pivot (MP, m=7/f=6, age=62.4±6.2 years) or posterior stabilized (PS, m=7/f=5, age=63.7±8.9 years) implants, and were compared to 13 controls (CTRL, m=7/f=6, age=63.9±4.3 years). All patients completed a gait analysis within one month prior and 12 months following surgery, CTRLs completed the protocol once. A waveform F-Test Method (WFM) was used to compare the variance in knee biomechanics variables at each interval of the gait cycle. Results. Preoperatively, the PS group had greater sagittal knee angle variability compared to the MP (32–58% gait cycle) and CTRL (21–53% gait cycle) groups. Postoperatively, no difference in sagittal knee angle variability existed between any of the groups. Preoperatively, sagittal knee moment variability was greater in the MP (2–39% gait cycle) and PS (5–19% and 42–57% gait cycle) groups compared to the CTRL. Postoperatively, sagittal knee moment was lower in the MP (49–55% gait cycle) and greater in the PS (23–36% gait cycle) compared to the CTRL. Knee power variability was greater preoperatively in the MP (52–61% gait cycle) and PS (52–62% gait cycle) compared to the CTRL. Postoperatively, knee power variability was lower in the MP (17–22% and 45–50% gait cycle) and PS (6–23%, 34–41% and 45–49% gait cycle) compared to the CTRL group. Conclusions. Preoperatively, knee OA patients have greater variability in knee moments than CTRLs during the
Introduction. In 2015, the healthcare system
Introduction. Stand to sit pelvis kinematics is commonly considered as a rotation around the bicoxofemoral axis. However, abnormal kinematics could occur for patients with musculoskeletal disorders affecting the hip-spine complex. The aim of this study is to perform a quantitative analysis of the stand to sit pelvis kinematics using 3D reconstruction from bi-planar x-rays. Materials and Methods. Thirty healthy volunteers as a control group (C), 30 patients with hip pathology (Hip) and 30 patients with spine pathology (Spine) were evaluated. All subjects underwent standing and sitting full-body bi-planar x-rays. 3D reconstruction was performed in each configuration and then translated such as the middle of the line joining the center of each acetabulum corresponds to the origin. Rigid registration quantified the finite helical axis (FHA) describing the
We have developed a decellularised porcine superflexor tendon (pSFT), which has shown promising regenerative capacity in an ovine model of anterior cruciate ligament (ACL) repair. This study investigated the strain rate dependent and dynamic mechanical properties of native and decellularised pSFTs. Decellularisation was carried out using a previously established procedure, including antibiotic washes, low concentration detergent (0.1% sodium dodecyl sulphate) washes and nuclease treatments. Three different strain rates were employed: 1, 10 & 100%s-1 (n=6 for all groups). Toe-region modulus (E0), linear-region modulus (E1),
The responsiveness of the Manchester–Oxford Foot
Questionnaire (MOXFQ) was compared with foot/ankle-specific and
generic outcome measures used to assess all surgery of the foot
and ankle. We recruited 671 consecutive adult patients awaiting
foot or ankle surgery, of whom 427 (63.6%) were female, with a mean
age of 52.8 years (18 to 89). They independently completed the MOXFQ,
Short-Form 36 (SF-36) and EuroQol (EQ-5D) questionnaires pre-operatively
and at a mean of nine months (3.8 to 14.4) post-operatively. Foot/ankle
surgeons assessed American Orthopaedic Foot and Ankle Society (AOFAS)
scores corresponding to four foot/ankle regions. A
Introduction and Objective. Found in bone-associated prosthesis, Cutibacterium acnes (C. acnes) is isolated in more than 50% of osteoarticular prosthesis infections, particularly those involving shoulder prostheses. Ongoing controversies exist concerning the origin of C. acnes infection. Few reports construct a reasonable hypothesis about probable contaminant displaced from the superficial skin into the surgical wound. Indeed, despite strict aseptic procedures, transecting the sebaceous glands after incision might result in C. acnes leakage into the surgical wound. More recently, the presence of commensal C. acnes in deep intra-articular tissues was reported. C. acnes was thus detected in the intracellular compartment of macrophages and stromal cells in 62.5% of the tested patients who did not undergo skin penetration. Among bone stromal cells, mesenchymal stem cells (MSCs) are predominantly found in bone marrow and periosteum. MSCs are the source of osteogenic lines of cells capable of forming bone matter. In this study, the pathogenicity of C. acnes in bone repair context was investigated. Materials and Methods. Human bone marrow derived MSCs were challenged with C. acnes clinical strains harvested from non-infected bone site (Cb). The behaviour of Cb strain was compared to C. acnes took from orthopaedic implant-associated infection (Ci). The infective capabilities of both strains was determined following gentamicin-based antibiotic protection assay. The morphology and ultrastructural analysis of infected MSCs was performed respectively through CLSM pictures of Phalloidin. ®. stained MSCs cytoskeleton and DAPI labelled Cb, and transmission and scanning electron microscopies. The virulence of intracellular Ci and Cb (Ci-MSCs and Cb-MSCs) was investigated by biofilm formation on non-living bone materials; and the immunomodulatory response of infected MSCs was investigated (PGE-2 and IDO secretion detected by ELISA). Bone cells (osteoblasts and PMA differentiated macrophages) were then challenged with Cb-MSCs and Ci-MSCs. Intracellular accumulation of ROS within infected macrophages was assessed by flow cytometry after 2 h of infection and the catalase production by Cb-MSC and Ci-MSC was evaluated. Statistical analyses were performed using Mann & Whitney test. Results. Following MSCs infection by C. acnes, the rate of viable bacteria inside MSCs was about 4% and 6% for Cb and Ci, respectively. Cb showed however a lower invasiveness in comparison to Ci (0.6-fold, p=0.01), confirming the higher pathogenicity of Ci. The ultrastructural and morphology analysis of infected MSCs confirmed the presence of bacteria free in MSCs cytoplasm, localized between F-actin fibers of MSCs, which preserved their elongated morphology. Considering the high level of secreted immunomodulatory mediators (PGE-2 and IDO), our results suggest that Cb-infected MSCs could promote a
The
Abstract. OBJECTIVES. Staphylococcus aureus is one of the most common pathogens in orthopaedic biomaterial-associated infections. The
Abstract. Objectives. Assess and characterise the suitability of a novel silk reinforced biphasic 3D printed scaffold for osteochondral tissue regeneration. Methods. Biphasic hybrid scaffolds consisted of 3D printed poly(ethylene glycol)-terephthalate-poly(butylene terephthalate)(PEGT/PBT) scaffold frame work (pore size 0.75mm), which has been infilled with a cast and freeze dried porous silk scaffold (5×5×2mm. 3. ), in addition to a seamless silk top layer (1mm). Silk scaffolds alone were used as controls. Both the biphasic and control scaffolds were characterised via uniaxial compression testing (strain rate 0.1mm/min), and the potential biocompatibility of the scaffolds was tested via in vitro culture of seeded bone marrow stromal cells post fabrication. Results. Uniaxial compression testing showed that the biphasic scaffolds (N=4) initially demonstrated similar behaviour on a stress-strain curve to a silk scaffold alone control group (N=6), until a strain of 30% was reached. After 30% strain, load was
Mesoporous bioactive glasses (MBGs) have been widely studied as bone regeneration systems, due to their bioactivity and ability to store and release therapeutic agents with specific biological functions. The incorporation of these nanomaterials into a thermosensitive hydrogel (TSH), in which a solution undergoes a sol-gel
The fibrocartilaginous enthesis displays a complex interface between two mechanically dissimilar tissues, namely tendon and bone. This graded
Cell sheets are manufactured from a high-density cell layer stabilized by its own freshly produced extracellular matrix (ECM). They could serve as versatile scaffolds for tissue repair. Unfortunately, their production often remains time-consuming requiring weeks of culturing. Ligament cell sheets are so far barely available. Regarding musculoskeletal tissues exposed to high repetitive biomechanical forces, the stability of cell sheets is insufficient. It could help to combine them with a biomechanical competent scaffold e.g. produced by an embroidering technique. Hence, we wanted to (1) develop a very rapid strategy to produce ACL ligamentocyte sheets within 24 h by using a thermoresponsive polymer surface, (2) use the sheets for scaffold seeding and (3) reflect the fibrocartilaginous
Bone tissue engineering is a promising strategy to treat the huge number of bone fractures caused by progressive population ageing and diseases i.e., osteoporosis. The bioactive and biomimetic materials design modulating cell behaviour can support healthy bone tissue regeneration. In this frame, type I collagen and hydroxyapatite (HA) have been often combined to produce biomimetic scaffolds. In addition, mesoporous bioactive glasses (MBGs) are known for their ability to promote the deposition of HA nanocrystals and their potential to incorporate and release therapeutic ions. Furthermore, the use of 3D printing technologies enables the effective design of scaffolds reproducing the natural bone architecture. This study aims to design biomimetic and bioactive 3D printed scaffolds that mimic healthy bone tissue natural features in terms of chemical composition, topography and biochemical cues. Optimised collagenous hybrid systems will be processed by means of extrusion 3D printing technologies to obtain high resolution bone-like structures. Protocols of human co-cultures of osteoblasts and osteoclasts will be developed and used to test the 3D scaffolds. Type I collagen has been combined with rod-like nano-HA and strontium containing MBGs (micro- and nano-sized particles) in order to obtain hybrid systems resembling the composition of native bone tissue. A comprehensive rheological study has been performed to investigate the potential use of the hybrid systems as biomaterial inks. Mesh-like structures have been obtained by means of extrusion-based technologies exploiting the freeform reversible embedding of suspended hydrogels (FRESH) approach. Different crosslinking methods have been tested to improve final constructs mechanical properties. Both crosslinked and non-crosslinked biomaterials were cultured with human osteoblasts and osteoclasts to assay the hybrid matrix biocompatibility as well as its influence on cell behaviour. Homogeneous hybrid systems have been successfully developed and characterised, proving their suitability as biomaterial inks for 3D printing technologies. Mesh-like structures have been extruded in a thermo-reversible gelatine slurry, exploiting the sol-gel
During OA the homeostasis of healthy articular chondrocytes is dysregulated, which leads to a phenotypical
Tendon-to-bone multi-tissue
To assess healing pattern of Achilles tendons across the gap created by a percutaneous tenotomy and maintained by cast in club feet. Twenty-one tenotomies in 16 patients (Age range 12 weeks-36 months) were monitored with dynamic and static ultrasonographic studies. Ultrasounds were performed before and immediately after tenotomy and at approximately 3, 6 and 12 weeks post tenotomy. Cast removal was done at three weeks. Two patients above age of two were casted for 6 weeks. The healing pattern went through different phases although they were not distinctively exclusive from each other and did show considerable overlap. First phase showed formation of a bulbous mass with some continuity of scar tissue across tendon gap. The
Introduction: In total hip arthroplasty (THA) an optimal fit and fill of the stem is essential for stable fixation. Thus femur morphology must be studied during pre-op planning (implant choice, sizing, positioning) or when a new stem is to be designed. Using plain AP x-ray analysis and the definition of a simple two-level parameter (canal flare index, CFI), Noble et al. identified an age related
Aim: Assess healing pattern of Achilles tendons across gap created by percutaneous tenotomy and maintained by cast in club feet. Methods and Results: 21 tenotomies in 16 patients (Age range 12 weeks–36 months) were monitored with dynamic and static ultrasonographic studies. Ultrasounds performed before, immediately after and at approximately 3, 6, 12 weeks post tenotomy. Cast removal was done at 3 weeks. Two patients above age of two were casted for 6 weeks. The healing pattern went through different phases although they were not distinctively exclusive from each other and did show considerable overlap. First phase showed formation of bulbous mass with some continuity of scar tissue across tendon gap. The
Aim: To assess the healing pattern of Achilles tendons across the gap created by a percutaneous tenotomy and maintained by cast in club feet. Methods and Results: 21 tenotomies in 16 patients (Age range 12 weeks-36 months) were monitored with dynamic and static ultrasonographic studies Ultrasounds were performed before and immediately after tenotomy and at approximately 3, 6 and 12 weeks post tenotomy. Cast removal was done at three weeks. Two patients above age of two were casted for 6 weeks. The healing pattern went through different phases although they were not distinctively exclusive from each other and did show considerable overlap. First phase showed formation of a bulbous mass with some continuity of scar tissue across tendon gap. The
Aims. Our study aimed to 1) Describe the changes in spinopelvic mobility when
The unparalleled events of the year 2020 continue to evolve and challenge the worldwide community on a daily basis. The COVID-19 pandemic has had a major impact on all aspects of our lives, and has caused major morbidity and mortality around the globe. The impact of COVID-19 on the practice of orthopedic surgery has been substantial with practice shutdowns, elective surgery restrictions, heightened utilization of telemedicine platforms and implementation of precautionary measures for in-person clinic visits. During this
Background. To complement subjective patient-reported outcome measures, objective assessments are needed. Activity is an objective clinical outcome which can be measured with wearable activity monitors (AM). AM's have been validated and used in joint arthroplasty patients to count postures, walking or transfers. However, for demanding patients such as after sports injury, running is an important activity to quantify. A new AM algorithm to distinguish walking from running is trialed in this validation study. Methods. Test subjects (n=9) performed walking and running bouts of 30s duration on a treadmill at fixed speeds (walking: 3, 4, 5, 7km/h, running: 5, 7, 9, 12, 15km/h) and individually preferred speeds (slow, normal, fast, maximum, walk/run transition). Flat and inclined surfaces (8%, 16%), different footwear (soft, hard, barefoot) and running styles (hind/fore-foot) were tested. An AM (3D accelerometer) was worn on the lateral thigh. Previously validated algorithms to classify all gait as walking were adapted to differentiate running from walking, the main criterium being vertical acceleration peaks exceeding 2g within each subsequent 2s-interval. Independently annotated video observation served as reference. Results. A total of 312 events had to be classified. Walking bouts (162) were correctly identified in 158 cases resulting in 97.5% detection accuracy. Running bouts (150) were correctly identified in 146 cases (97.3%). In 8 walking bouts (5.0%), an additional running event was falsely detected. These happened at 7km/h and maximum (>8.6km/h) walking speed and during continuous walk/run
Objectives. After an injury, the biological reattachment of tendon to bone is a challenge because healing takes place between a soft (tendon) and a hard (bone) tissue. Even after healing, the
Aims. Patellofemoral arthroplasty (PFA) has experienced significant
improvements in implant survivorship with second generation designs.
This has renewed interest in PFA as an alternative to total knee
arthroplasty (TKA) for younger active patients with isolated patellofemoral
osteoarthritis (PF OA). We analysed the cost-effectiveness of PFA versus TKA
for the management of isolated PF OA in the United States-based
population. Patients and Methods. We used a Markov
Previously, we reported impaired biomechanical bone properties and inferior bone matrix quality in tachykinin1 (Tac1)-deficient mice lacking the sensory neuropeptide substance P (SP). Additionally, fracture callus development is affected by the absence of SP indicating a critical effect of sensory nerve fibers on bone health and regeneration. For α-calcitonin gene-related peptide (α-CGRP)-deficient mice, a profound distortion of bone microarchitecture has also been described. We hypothesize that SP and α-CGRP modulate inflammatory as well as pain-related processes and positively affect bone regeneration during impaired fracture healing under osteoporotic conditions. Therefore, this study investigates the effects of SP and α-CGRP on fracture healing and fracture-related pain processes under conditions of experimental osteoporosis using SP- and α-CGRP-deficient mice and WT controls. We ovariectomized female WT, Tac1−/− and α-CGRP−/− mice (age 10 weeks, all strains on C57Bl/6J background) and set intramedullary fixed femoral fractures in the left femora 28 days later. We analyzed pain threshold (Dynamic Plantar Aesthesiometer Test) and locomotion (recorded at day and night, each for 1 hour, EthoVision®XT, Noldus) at 5, 9, 13, 16 and 21 days after fracture. At each time point, fractured femora were prepared for histochemical analysis of callus tissue composition (alcian blue/sirius red staining). Pain threshold is significantly higher in Tac1−/− mice 13 days after fracture and tends to be higher after 21 days compared to WT controls. In contrast, touch sensibility was similar in α-CGRP−/− mice and WT controls but compared to Tac1−/− mice pain threshold was significantly lower in α-CGRP−/− mice 13 and 16 days and tends to be lower 21 days after fracture. Locomotion of Tac1−/− mice during daylight was by trend higher 9 days after fracture and significantly higher 16 days after fracture whereas nightly locomotion is reduced compared to WT mice. Analysis of locomotion during daylight or night revealed no differences between α-CGRP−/− and WT mice. During early fracture healing phase, 5 and 9 days after fracture,
Introduction. Post op cup anatomical and functional orientation is a key point in THP patients regarding instability and wear. Recently literature has been focused on the consequences of the
Introduction. In order to achieve good clinical results in TKA, soft tissue balance is important. Soft tissue balance is closely related to knee kinematics which affects clinical results. Modified gap balancing technique is one of the standard techniques for posterior stabilized (PS) TKA. On the other hand, appropriate load for the measurement of gap balance has not been established. The purpose of the present study is to measure the mechanical properties of soft tissue structure of knee sleeve in flexion and extension during PS TKA using newly developed balancer. The understanding of the mechanical properties is crucial. In particular if these properties are used as input for surgical procedures, standard technique for many surgeons will be established. Materials and Methods. Medial compartmental osteoarthrosis (OA) patients (13 female and 7 male) were evaluated. Average age, BMI, and Varus deformity were 72.1 years, 26.9, and 12 degrees, respectively. The newly developed center paddle balancer consists of a built-in spring (Fig. 1). Figure 2 shows the sequence of surgery and measurements. In the surgery, we measured the balance (degrees in Figure 1, A) and distance (mm in Figure 1, B) in extension with a load (Figure 1,C) at
At our tertiary, large, academic healthcare system, we have access to an academic medical center (AMC), a community based, orthopedic friendly, efficient hospital (CBH) and several ambulatory care centers (ASC) which are being prepared to provide same day discharge (SDD) TJA and UKA. We had a near-capacity AMC with an excellent ability to care for medically and technically complicated TJA patients. However, efficiency was less than desired regardless of case complexity with an average effective case time of 4 hours. Concurrently, the orthopaedically, under-utilized community-based hospital (CBH) wanted to increase volume, improve margins, and become a TJA Center of Excellence with the ability to provide an efficient Hospital Outpatient Department (HOPD) and SDD TJA surgery experience. Methods. The CBH had a main operating floor and a separate floor of four OR suites which were repurposed with the goal of utilizing these rooms for TJA four days per week with an average of 3.5 cases per room per day. We preferentially performed primary, uncomplicated TJA, UKA, and minimally invasive TJA at the CBH. Revision surgeries, patients with extensive medical comorbidities, and complex primary surgeries would be performed at the AMC. Our goals were to decrease costs, readmissions, length of stay, and increase margins at the CBH while increasing efficiency, revenue and volume. Protocols were developed to facilitate SDD UKA and THA at both hospitals as well as rapid recovery protocols for TKA at both hospitals with the understanding that the CBH would perform more of these cases but the efficiency could also be implemented at the AMC when possible. We also needed a strategy to deal with TKA and eventually THA being removed from the Inpatient Only (IPO) list. CMS has utilized the “Two-Midnight Rule” to define outpatient status for both THA and TKA. This has distinct financial implications for the facility's reimbursement with outpatient being $10,123 on average versus $12,380 for inpatient status. A protocol-based system was put in place to make both hospitals compliant with the removal of TKA from the IPO List in order to avoid Quality Improvement Organization (QIO) and Recovery Audit Contractor (RAC) after implementation. Results. Comparing FY 2018 to FY 2019, volume increased 26.4% at the CBH. Outpatient case volume rose substantially from 14 cases to 243. Volumes were slightly decreased at the AMC (−4.57%) resulting in a substantial increase in margin contribution for the parent enterprise. Quality metrics at the CBH (surgical site infections (SSI), length of stay (LOS), readmissions, and mortality) were improved. LOS improved from 52% to 71% discharge before 48 hours. The LOS decreased 12% for THA and 8.1% for TKA. CBH readmission rates decreased from 1.38% to 0.9% with no deaths. Surgeon satisfaction is greatly improved as their volume, efficiency, quality metrics, and finances were enhanced. Financial performance was improved in aggregate and per case for the CBH. Although the CBH per-case revenue was 80.3% and 74.4% of the AMC for THA and TKA: the net margins were 3.6% and 18.8% higher for THA and TKA, respectively. The increased efficiency, lower hospital cost and higher volume at the CBH allowed for an increase in revenue despite lower reimbursement per case. Conclusions. A shifting reimbursement landscape, value-based payment initiatives, and increasing volume have challenged traditional TJA delivery systems. This demonstrates one strategy to help hospital systems improve net margins while improving patient care despite lower net revenue per TJA episode. These strategies will become increasingly important going forward with the
Introduction. Musculoskeletal diseases are the biggest cause of morbidity worldwide, with low back pain (LBP) being the leading cause. Forty percent of LBP cases are caused by disease of shock absorbers in the spine known as intervertebral discs (IVDs). The IVDs enable the spine to twist and bend, whilst absorbing load during normal daily activities. The durability of this tissue is sustained by the cells of the spine and so during disease or mechanical damage these cells can behave abnormally further damaging the disc and stimulating local nerves causing extreme pain. Degradation of the intervertebral disc (IVD) currently has no preventative treatment; an injectable hydrogel biomaterial could reinforce disc mechanical properties and promote tissue regeneration. Methods and Results. We present an injectable range of hydrogel biomaterials made from water, clay and polymer that set at 37°C. The materials were made at 80°C polymerised in water and stored at 70°C to remain liquid. The physical properties of the materials were assessed using various methods, including mechanical assessment using temperature-controlled rheometry to monitor the liquid-hydrogel
Summary. Both endogenous lubricin and injectable hyaluronic acid reduced cartilage friction coefficients, but by distinct mechanisms. Lubricin operated in boundary mode and hyaluronic acid shifted lubrication to mixed or hydrodynamic mode. Introduction. Intra-articular injections of viscous agents and boundary lubricants have been presented as options to mitigate the progression of articular cartilage damage after the onset of osteoarthritis. 1,2. Mechanically, these injections are predicted to lower the friction coefficient within a load bearing joint and consequently slow the propagation of damage at the articular surface. Tribologically, boundary lubricants and viscous agents are hypothesised to be effective through different mechanisms affecting boundary-mode lubrication and