Aseptic loosening of the option stemmed tibial tray in the Zimmer NexGen LPS total knee arthroplasty system.

BACKGROUND: We investigated the relationship between the backside deformation of polyethylene (PE) tibial inserts and aseptic loosening of the Option stemmed tibial tray used with Zimmer NexGen posterior-stabilised (PS) devices. We hypothesized that explanted inserts used in PS designs would exhibit greater extents of PE backside deformation than those used in equivalent cruciate retaining (CR) designs and that PE inserts retrieved from total knee arthroplasties (TKAs) revised for aseptic tibial tray loosening would exhibit greater extents of backside deformation than TKAs revised for other reasons. METHODS: A total of 73 explanted fixed-bearing TKAs (42 CR and 31 PS) were examined. PE components underwent geometric examination with a coordinate measuring machine using validated techniques. Multiple regression modelling was used to identify variables associated with revision secondary to aseptic loosing and to determine factors associated with increased PE backside deformation. RESULTS: PE inserts retrieved from TKAs with aseptic loosening had significantly greater backside deformation than those retrieved from TKAs revised for other reasons (p < 0.001). Greater PE backside deformation was significantly associated with larger tray/insert clearance heights (p < 0.001), thinner inserts (p < 0.001) and PS TKAs (p = 0.001). CONCLUSION: PE backside deformation was significantly greater in the PS TKAs. This may provide one explanation for the increased rate of aseptic loosening reported with the Option tibial tray used with the Legacy Posterior Stabilised (LPS) system.

Artificial Intelligence You Can Trust: What Matters Beyond Performance When Applying Artificial Intelligence to Renal Histopathology?

Although still in its infancy, artificial intelligence (AI) analysis of kidney biopsy images is anticipated to become an integral aspect of renal histopathology. As these systems are developed, the focus will understandably be on developing ever more accurate models, but successful translation to the clinic will also depend upon other characteristics of the system.In the extreme, deployment of highly performant but "black box" AI is fraught with risk, and high-profile errors could damage future trust in the technology. Furthermore, a major factor determining whether new systems are adopted in clinical settings is whether they are "trusted" by clinicians. Key to unlocking trust will be designing platforms optimized for intuitive human-AI interactions and ensuring that, where judgment is required to resolve ambiguous areas of assessment, the workings of the AI image classifier are understandable to the human observer. Therefore, determining the optimal design for AI systems depends on factors beyond performance, with considerations of goals, interpretability, and safety constraining many design and engineering choices.In this article, we explore challenges that arise in the application of AI to renal histopathology, and consider areas where choices around model architecture, training strategy, and workflow design may be influenced by factors beyond the final performance metrics of the system.

The feasibility and acceptability of assessing and managing sarcopenia and frailty among older people with upper limb fracture.

BACKGROUND: sarcopenia and frailty are associated with increased risk of falls and fractures. This study evaluated the feasibility of assessing sarcopenia and frailty among older people attending fracture clinics. METHODS: patients aged 65+ years with an arm fracture attending fracture clinics in one UK city were recruited. Sarcopenia was assessed using gait speed, grip strength, skeletal muscle mass index SMI, SARC-F questionnaire and the European Working Group on Sarcopenia in Older People (EWGSOP) I and II criteria. Frailty was assessed using Fried Frailty Phenotype (FFP), FRAIL scale, PRISMA-7, electronic Frailty Index (e-FI), Clinical Frailty Score (CFS) and Study of Osteoporotic Fracture. The sensitivity and specificity of each tool was calculated against the EWGSOP II criteria (sarcopenia) and FFP (frailty). Patients identified to have either condition were referred for Comprehensive Geriatric Assessment (CGA). Interviews with 13 patients and nine staff explored the acceptability of this process. RESULTS: hundred patients (Mean age 75 years) were recruited. Most sarcopenia and frailty assessments were quick with complete data collection and were acceptable to patients and staff. Sarcopenia was identified among 4-39% participants depending on the tool and frailty among 9-25%. Both conditions were more common among men than women with all tools. The SARC-F and PRISMA-7 had the best sensitivity (100 and 93%, respectively) and specificity (96 and 87%). CGA among 80% of referred participants led to three interventions per participant (e.g. medication changes and investigations). CONCLUSION: SARC-F and PRISMA-7 are recommended for use in fracture clinics to screen for sarcopenia and frailty.

Antibiotic-loaded Bone Cement in the Management of Neosternal Osteomyelitis.

Antibiotic-loaded bone cement is an alternative treatment option that can be used in the surgical management of osteomyelitis requiring bone resection and reconstruction. Current literature provides a focus on its use within the orthopedic patient group with scarce literature surrounding the cardiothoracic patient demographic. We hereby demonstrate the use of an antibiotic-loaded bone cement in the definitive management of neosternal osteomyelitis and nonunion, avoiding the need for further complex autografting and internal fixation.

2019 EULAR points to consider for non-physician health professionals to prevent and manage fragility fractures in adults 50 years or older.

OBJECTIVE: To establish European League Against Rheumatism (EULAR) points to consider for non-physician health professionals to prevent and manage fragility fractures in adults 50 years or older. METHODS: Points to consider were developed in accordance with EULAR standard operating procedures for EULAR-endorsed recommendations, led by an international multidisciplinary task force, including patient research partners and different health professionals from 10 European countries. Level of evidence and strength of recommendation were determined for each point to consider, and the mean level of agreement among the task force members was calculated. RESULTS: Two overarching principles and seven points to consider were formulated based on scientific evidence and the expert opinion of the task force. The two overarching principles focus on shared decisions between patients and non-physician health professionals and involvement of different non-physician health professionals in prevention and management of fragility fractures. Four points to consider relate to prevention: identification of patients at risk of fracture, fall risk evaluation, multicomponent interventions to prevent primary fracture and discouragement of smoking and overuse of alcohol. The remaining three focus on management of fragility fractures: exercise and nutritional interventions, the organisation and coordination of multidisciplinary services for post-fracture models of care and adherence to anti-osteoporosis medicines. The mean level of agreement among the task force for the overarching principles and the points to consider ranged between 8.4 and 9.6. CONCLUSION: These first EULAR points to consider for non-physician health professionals to prevent and manage fragility fractures in adults 50 years or older serve to guide healthcare practice and education.

Delayed post-traumatic presentation of severe sternal osteomyelitis: A strong multidisciplinary effort and a novel reconstruction technique for a challenging case.

Sternal osteomyelitis is a morbid and challenging condition, which can rarely occur after trauma, with no established consensus over best therapeutic options. In this case, a 47-year-old man with history of intravenous drug use presented 11 weeks after a minor blunt chest trauma with a severe necrotizing osteomyelitis involving sternum, muscles, fascia and subcutaneous tissue and positive blood cultures for Methicillin Sensitive Staphylococcus aureus. Alongside tailored antibiotic therapy, extensive surgical debridement was performed, leaving a full thickness 3 × 4 cm sternal defect and a large skin defect. After 4 weeks of antibiotics and Vacuum-Assisted-Closure pump, a novel reconstruction technique was utilized, with full collaborations of thoracic surgeons, orthopaedic surgeons and plastic surgeons. An autologous tricortical iliac crest bone graft was harvested and shaped to fit the full-thickness sternal defect, while two titanium sigmoid-shaped clavicle plates were used for internal fixation of the autograft. The large skin defect was covered with a pedicled myocutaneous latissimus dorsi flap. Integrity and stability of the chest wall was fully restored, and infection was completely eradicated. No complications occurred and the patient was well at the 18 months follow-up. To the best of our knowledge, this is the first report on autologous iliac crest bone graft in the treatment of sternal osteomyelitis. In this case, it proved to be a viable therapeutic option, providing good long-term clinical and cosmetic results.

Prevention and management of osteoporotic fractures by non-physician health professionals: a systematic literature review to inform EULAR points to consider.

OBJECTIVE: To perform a systematic literature review (SLR) about the effect of non-pharmacological interventions delivered by non-physician health professionals to prevent and manage osteoporotic fractures. METHODS: Eight clinical questions based on two criteria guided the SLR: (1) adults≥50 years at high risk of osteoporotic fracture and (2) interventions delivered by non-physician health professionals to prevent and manage osteoporotic fractures. Interventions focused on diagnostic procedures to identify risk of falling, therapeutic approaches and implementation strategies. Outcomes included fractures, falls, risk of falling and change in bone mineral density. Systematic reviews and randomised controlled trials were preferentially selected. Data were synthesised using a qualitative descriptive approach. RESULTS: Of 15 917 records, 43 articles were included. Studies were clinically and methodologically diverse. We identified sufficient evidence that structured exercise, incorporating progressive resistance training delivered to people who had undergone hip fracture surgery, and multicomponent exercise, delivered to people at risk of primary fracture, reduced risk of falling. The effectiveness of multidisciplinary fracture liaison services in reducing refracture rate was confirmed. There was insufficient evidence found to support the effectiveness of nutrients and falls prevention programmes in this patient population. CONCLUSION: Despite study heterogeneity, our SLR showed beneficial effects of some interventions delivered by non-physician health professionals and the positive impact of multidisciplinary team working and patient educational approaches to prevent and manage osteoporotic fractures. These results informed a EULAR taskforce that developed points to consider for non-physician health professionals to prevent and manage osteoporotic fractures.

A National Survey of Undergraduate Suture and Local Anesthetic Training in the United Kingdom.

BACKGROUND: Suturing is a skill expected to be attained by all medical students on graduation, according to the General Medical Council's (GMC) Tomorrow's Doctors. There are no GMC recommendations for the amount of suture training required at medical school nor the level of competence to be achieved. This study examines the state of undergraduate suture training by surveying a sample of medical students across the United Kingdom. METHODS: We distributed a survey to 17 medical schools to be completed by undergraduates who have undergone curricular suture training. The survey included questions relating to career intention, hours of curricular suture training, hours of additional paid training, confidence in performing various suture techniques and knowledge of their indications. We also asked about the students' perceived proficiency at injecting local anesthetic and their overall opinion of medical school suture training. RESULTS: We received responses from 705 medical students at 16 UK medical schools. A total of 607 (86.1%) medical students had completed their scheduled curricular suture training. Among them, 526 (86.5%) students reported inadequate suture training in medical school and 133 (21.9%) students had paid for additional training. Results for all competence markers were significantly lower than the required GMC standards (p < 0.001). Students who had paid for additional training were significantly more confident across all areas examined (p < 0.001). CONCLUSIONS: Our study identified a deficiency in the curricular suture training provided to the medical students surveyed. These findings suggest that medical schools should provide more opportunities for students to develop their suturing skills to achieve the GMC standard.

Pseudotumour formation due to tribocorrosion at the taper interface of large diameter metal on polymer modular total hip replacements.

We present an in-depth failure analysis of two large diameter bearing metal-on-polymer (MoP) modular total hip replacements, which have required revision surgery due to pseudotumour formation. The failure analysis showed a discrete pattern of material loss from the distal end of the head taper/stem trunnion interface. We postulate that the use of a proximal contacting taper design had provided insufficient mechanical locking between the head and the stem, enabling the head to toggle on the trunnion. In addition, the difference in angle between the taper and the trunnion formed a crevice between the two components. Through a combination of crevice environment, mechanically assisted corrosion, mechanical wear and erosion; debris and metal-ions have been released resulting in the adverse local tissue reactions (ALTR).

Taking tissue engineering principles into theatre: retrieval analysis from a clinically translated case.

AIM: Tissue engineering has enormous potential for the regeneration of bone defects. Approximately 4 years ago we reported on a 62 year old patient who underwent treatment of a benign cyst in the proximal femur by impaction bone grafting supplemented with autologous bone marrow. The cyst and symptoms subsequently recurred and this patient has now required a total hip replacement. This has provided a rare opportunity for ex vivo analysis of clinically applied tissue engineered bone. MATERIALS & METHODS: The femoral head was retrieved at surgery and the structural and functional characteristics of the tissue engineered bone were analyzed by micro-computed tomography, histology and mechanical testing. RESULTS: The impacted bone demonstrated a trabecular structure that contained islands of nonincorporated graft. The graft was denser than the patient's trabecular bone with comparable strength. The cyst material had penetrated along the channel of bone and an increased number of osteoclasts were observed. DISCUSSION: This study has provided detailed ex vivo analysis of retrieved human tissue engineered bone and possible reasons for the observed construct failure are discussed in this article. The impacted bone displayed some evidence of remodeled trabecular structure, although the bone marrow aspirate that was initially combined with the allograft contained a relatively low concentration of osteoprogenitor cells. Cellular augmentation was insufficient to overcome the osteoclastic process associated with renewed cyst formation. Concentration or culture expansion of osteoprogenitor cells from aspirated bone marrow is recommended for biological augmentation of bone graft.

Expansion of human bone marrow stromal cells on poly-(DL-lactide-co-glycolide) (PDL LGA) hollow fibres designed for use in skeletal tissue engineering.

Strategies to expand human bone marrow stromal cells (HBMSC) for bone tissue engineering are a key to revolutionising the processes involved in three-dimensional skeletal tissue reconstruction. To facilitate this process we believe the use of biodegradable porous poly(DL-lactide-co-glycolide) (PDL LGA) hollow fibres as a scaffold used in combination with HBMSC to initiate natural bone repair and regeneration offers a potential solution. In this study, the biocompatibility of 75:25 PDL LGA fibres with HBMSC and the capacity of a PDL LGA fibre-associated HBMSC-monolayer to establish an osteogenic phenotype in vivo was examined. A high proportion of HBMSC survived when expanded on PDL LGA fibres for 6 days, with only 10% of the propidium iodide (pI)-labelled population represented in the sub-G1 DNA peak on analysis by flow cytometry. Tracking carboxy-fluorescein diacetate, succinimidyl ester (CFSE)-labelled HBMSC by flow cytometry indicated that HBMSC attachment to the P(DL)LGA fibres does not interfere with their rate of proliferation. Furthermore, in response to osteogenic stimuli, HBMSC expanded on PDL LGA fibres can differentiate, as expected, along the osteogenic lineage with associated alkaline phosphatase activity. Following implantation into SCID mice, osteogenic-conditioned PDL LGA fibre-HBMSC graft resulted in type I collagen deposition and associated bone mineralisation and osteoid formation, as evidenced by immunohistochemistry and histology. These studies provide evidence that porous PDL LGA hollow fibre-HBMSC graft is an innovative biomaterial that offers new approaches to mesenchymal cell expansion, which could be utilised as a scaffold for skeletal tissue generation.

Adult mesenchymal stem cells and impaction grafting: a new clinical paradigm shift.

The demographic challenges of an increasingly aging population emphasize the need for innovative approaches to skeletal reconstruction to augment and repair skeletal tissue lost as a consequence of implant loosening, trauma, degeneration or in situations involving revision surgery requiring bone stock. These clinical imperatives to augment skeletal tissue loss have brought mesenchymal stem cells to the fore in combination with the emerging discipline of tissue engineering. To date, impaction bone grafting for revision hip surgery is a recognized technique to reconstitute bone utilizing morselized allograft to provide a good mechanical scaffold, although with little osteoinductive biological potential. This review details laboratory and clinical examples of a paradigm shift in the application of mesenchymal stem cells with allograft to produce a living composite using the principles of tissue engineering. This step change creates a composite that offers a biological and mechanical advantage over the current gold standard of allograft alone. This translation of tissue engineering concepts into clinical practice offers enormous input into the field of bone regeneration and has implications for translation and future change in skeletal orthopedic practice in an increasingly aging population.

Taking tissue-engineering principles into theater: augmentation of impacted allograft with human bone marrow stromal cells.

Human bone marrow contains bone progenitor cells that arise from multipotent mesenchymal stem cells. Seeding bone progenitor cells onto a scaffold can produce a 3D living composite with significant mechanical and biological potential. This article details laboratory and clinical findings from two clinical cases, where different proximal femoral conditions were treated using impacted allograft augmented with marrow-derived autogenous progenitor cells. Autologous bone marrow was seeded onto highly washed morselized allograft and impacted. Samples of the impacted graft were also taken for ex vivo analysis. Both patients made an uncomplicated clinical recovery. Imaging confirmed defect filling with encouraging initial graft incorporation. Histochemical and alkaline phosphatase staining demonstrated that a live composite graft with osteogenic activity had been introduced into the defects. These studies demonstrate that marrow-derived cells can adhere to highly washed morselized allograft, survive the impaction process and proliferate with an osteoblastic phenotype, thus creating a living composite.

Biological and mechanical enhancement of impacted allograft seeded with human bone marrow stromal cells: potential clinical role in impaction bone grafting.

With the demographics of an aging population the incidence of revision surgery is rapidly increasing. Clinical imperatives to augment skeletal tissue loss have brought mesenchymal stem cells to the fore in combination with the emerging discipline of tissue engineering. Impaction bone grafting for revision hip surgery is a recognized technique to reconstitute bone, the success of which relies on a combination of mechanical and biological factors. The use of morsellized allograft is currently the accepted clinical standard providing a good mechanical scaffold with little osteoinductive biological potential. We propose that applying the principles of a tissue engineering paradigm, the combination of human bone marrow stromal cells (hBMSCs) with allograft to produce a living composite, offers a biological and mechanical advantage over the current gold standard of allograft alone. This study demonstrates that hBMSCs combined with allograft can withstand the forces equivalent to a standard femoral impaction and continue to differentiate and proliferate along the bony lineage. In addition, the living composite provides a biomechanical advantage, with increased interparticulate cohesion and shear strength when compared with allograft alone.

Association between the abnormal expression of matrix-degrading enzymes by human osteoarthritic chondrocytes and demethylation of specific CpG sites in the promoter regions.

OBJECTIVE: To investigate whether the abnormal expression of matrix metalloproteinases (MMPs) 3, 9, and 13 and ADAMTS-4 by human osteoarthritic (OA) chondrocytes is associated with epigenetic "unsilencing." METHODS: Cartilage was obtained from the femoral heads of 16 patients with OA and 10 control patients with femoral neck fracture. Chondrocytes with abnormal enzyme expression were immunolocalized. DNA was extracted, and the methylation status of the promoter regions of MMPs 3, 9, and 13 and ADAMTS-4 was analyzed with methylation-sensitive restriction enzymes, followed by polymerase chain reaction amplification. RESULTS: Very few chondrocytes from control cartilage expressed the degrading enzymes, whereas all clonal chondrocytes from late-stage OA cartilage were immunopositive. The overall percentage of non-methylated sites was increased in OA patients (48.6%) compared with controls (20.1%): 20% versus 4% for MMP-13, 81% versus 47% for MMP-9, 57% versus 30% for MMP-3, and 48% versus 0% for ADAMTS-4. Not all CpG sites were equally susceptible to loss of methylation. Some sites were uniformly methylated, whereas in others, methylation was generally absent. For each enzyme, there was 1 specific CpG site where the demethylation in OA patients was significantly higher than that in controls: at -110 for MMP-13, -36 for MMP-9, -635 for MMP-3, and -753 for ADAMTS-4. CONCLUSION: This study provides the first evidence that altered synthesis of cartilage-degrading enzymes by late-stage OA chondrocytes may have resulted from epigenetic changes in the methylation status of CpG sites in the promoter regions of these enzymes. These changes, which are clonally transmitted to daughter cells, may contribute to the development of OA.