Biofilm formation by bacteria isolated from retrieved failed prosthetic hip implants in an in vitro model of hip arthroplasty antibiotic prophylaxis

Bacterial infection primarily with Staphylococcus spp. and Propionibacterium acnes remains a significant complication following total hip replacement. In this in vitro study, we investigated the efficacy of gentamicin loading of bone cement and pre- and postoperative administration of cefuroxime in the prevention of biofilm formation by clinical isolates. High and low initial inocula, representative of the number of bacteria that may be present at the operative site as a result of overt infection and skin contamination, respectively, were used. When a high initial inoculum was used, gentamicin loading of the cement did not prevent biofilm formation by the 10 Staphylococcus spp. and the 10 P. acnes isolates tested. Similarly, the use of cefuroxime in the fluid phase with gentamicin-loaded cement did not prevent biofilm formation by four Staphylococcus spp. and four P. acnes isolates tested. However, when a low bacterial inoculum was used, a combination of both gentamicin-loaded cement and cefuroxime prevented biofilm formation by these eight isolates. Our results indicate that this antibiotic combination may protect against infection after intra-operative challenge with bacteria present in low numbers as a result of contamination from the skin but would not protect against bacteria present in high numbers as a result of overt infection of an existing implant.

Functional and Physiological Determinants of Perceived Disability in Individuals Diagnosed with Osteoarthritis of the Hip

Objectives: The main objective of this pilot study was to investigate which standardized functional and physiological test best predicted perceived disability in a single group of 21 individuals diagnosed with osteoarthritis of the hip. Design: Men and women between 60 and 70 years old with osteoarthritis of the hip were selected. If participants passed study criteria, the Western Ontario McMaster University questionnaire (WOMAC), 6 Minute Walk Test (6MWT) and Timed up and Go (TUG), strength testing and aerobic testing were obtained in one single assessment. Results: Regression analysis revealed that wait time, hip abduction strength of the affected side, Aerobic Capacity (VO2 Peak), hip Extension Peak Torque, hip Flexion Peak Torque, TUG and 6MWT were significantly correlated with the WOMAC. Yet, the 6MWT had the highest significant correlation (r = -0.86, p ≤ 0.0001); R2 = 0.75 or 75% with the WOMAC total scores, (r = -0.82, p ≤ 0.0001); R2 = 0.67 or 67% with the WOMAC function and (r = -0.60, p = .002); R2 = 0.36 or 36% with the WOMAC stiffness. While the VO2 Peak revealed the highest significant correlation (r = 0.76, p ≤ .0001); R2 = 0.57 or 57% with the WOMAC pain. Conclusions: The 6MWT and the VO2 Peak seem to be essential functional and physiological assessment tools to determine perceived disability in individuals with hip OA. The perceived disability may provide new or comprehensive knowledge of the disability problems experienced by individuals with osteoarthritis of the hip, and the association of patient perception with objective measures of functional and physiological capacity might strengthen the clinical value of this knowledge.

Correlation of synovial fluid cytokine levels with histological and clinical parameters of primary and revision total hip and total knee replacements

We retrieved synovial tissue and fluid samples from patients undergoing primary total hip replacement (THR) (n 15), revision of aseptically loose THR (n 12), primary total knee replacement (TKR) (n 13) and revision of aseptically loose TKR (n 6). Several histological parameters were assessed on a relative scale of 1-4. Primary TJRs were clinically evaluated for degree of osteoarthrosis. Revision TJRs were assessed for migration of the implant, gross loosening and the degree of radiolucency. Cytokine levels in synovial fluid were determined with ELISA.

Nanoscale reinforced orthopaedic bone cement with graphene oxide - a possible solution to aseptic loosening of cemented hip implants? Preliminary results of an ongoing study

Hip replacement surgery is amongst the most common orthopaedic operations performed in the UK. Aseptic loosening is responsible for 40% of hip revision procedures. Aseptic loosening is a result of cement mantle fatigue. The aim of the current study is to analyse the effect of nanoscale Graphene Oxide (GO) on the mechanical properties of orthopaedic bone cement. Study Design A experimental thermal and mechanical analysis was conducted in a laboratory set up conforming to international standards for bone cement testing according to ISO 5583. Testing was performed on control cement samples of Colacryl bone cement, and additional samples reinforced with variable wt% of Graphene Oxide containing composites – 0.1%, 0.25%, 0.5% and 1.0% GO loading. Pilot Data Porosity demonstrated a linear relationship with increasing wt% loading compared to control (p<0.001). Thermal characterisation demonstrated maximal temperature during polymerization, and generated exotherm were inversely proportional to w%t loading (p<0.05) Fatigue strength performed on the control and 0.1 and 0.25%wt loadings of GO demonstrate increased average cycles to failure compared to control specimens. A right shift of the Weibull curve was demonstrated for both wt% available currently. Logistic regression analysis for failure demonstrated significant increases in number of cycles to failure for both specimens compared to a control (p<0.001). Forward Plan Early results convey positive benefits at low wt% loadings of GO containing bone cement. Study completion and further analysis is required in order to elude to the optimum w%t of GO which conveys the greatest mechanical advantage.

Factors that impact the sustainability of wait time management strategies for total joint replacement surgeries in canadian provinces

Pour répondre aux exigences du gouvernement fédéral quant aux temps d’attente pour les chirurgies de remplacement du genou et de la hanche, les établissements canadiens ont adopté des stratégies de gestion des listes d’attentes avec des niveaux de succès variables. Notre question de recherche visait à comprendre Quels facteurs ont permis de maintenir dans le temps un temps d’attente répondant aux exigences du gouvernement fédéral pendant au moins 6-12 mois? Nous avons développé un modèle possédant quatre facteurs, inspiré du modèle de Parsons (1977), afin d’analyser les facteurs comprenant la gouvernance, la culture, les ressources, et les outils. Trois études de cas ont été menées. En somme, le 1er cas a été capable d’obtenir les exigences pendant six mois mais incapable de les maintenir, le 2e cas a été capable de maintenir les exigences > 18 mois et le 3e cas a été incapable d’atteindre les objectifs. Des documents furent recueillis et des entrevues furent réalisées auprès des personnes impliquées dans la stratégie. Les résultats indiquent que l’hôpital qui a été en mesure de maintenir le temps d’attente possède certaines caractéristiques: réalisation exclusive de chirurgie de remplacement de la hanche et du genou, présence d’un personnel motivé, non distrait par d’autres préoccupations et un esprit d’équipe fort. Les deux autres cas ont eu à faire face à une culture médicale moins homogène et moins axés sur l’atteinte des cibles; des ressources dispersées et une politique intra-établissement imprécise. Le modèle d’hôpital factory est intéressant dans le cadre d’une chirurgie surspécialisée. Toutefois, les patients sont sélectionnés pour des chirurgies simples et dont le risque de complication est faible. Il ne peut donc pas être retenu comme le modèle durable par excellence.

Continuity of care and general wellbeing of patients with comorbidities requiring joint replacement

Aim. The aim of this paper is to examine the continuity of care and general wellbeing of patients with comorbidities undergoing elective total hip or knee joint replacement.
Background. Advances in medical science and improved lifestyles have reduced mortality rates in most Western countries. As a result, there is an ageing population with a concomitant growth in the number of people who are living with multiple chronic illnesses, commonly referred to as comorbidities. These patients often require acute care services, creating a blend of acute and chronic illness needs. For example, joint replacement surgery is frequently performed to improve impaired mobility associated with osteoarthritis.
Method. A purposive sample of twenty participants with multiple comorbidities who required joint replacement surgery was recruited to obtain survey, interview and medical record audit data. Data were collected during 2004 and 2005.
Findings. Comorbidity care was poorly co-ordinated prior to having surgery, during the acute care stay and following surgery and primarily entailed prescribed medicines. The main focus in acute care was patient throughput following joint replacement surgery according to a prescribed clinical pathway. General wellbeing was less than optimal: participants reported pain, fatigue, insomnia and alterations in urinary elimination as the chief sources of discomfort during the course of the study.
Conclusion. Continuity of care of comorbidities was lacking. Comorbidities affected patient general wellbeing and delayed recovery from surgery. Acute care, clinical pathways and the specialisation of medicine and nursing subordinated the general problem of patients with comorbidities. Systems designed to integrate and co-ordinate chronic illness care had limited application in the acute care setting. A multidisciplinary, holistic approach is required. Recommendations for further research conclude this paper.

Can a disease-specific education program augment self-management skills and improve Health-Related Quality of Life in people with hip or knee osteoarthritis?

Background: Patient education and self-management programs are offered in many countries to people with chronic conditions such as osteoarthritis (OA). The most well-known is the disease-specific Stanford Arthritis Self-Management Program (ASMP). While Australian and international clinical guidelines promote the concept of self-management for OA, there is currently little evidence to support the use of the ASMP. Several meta-analyses have reported that arthritis self-management programs had minimal or no effect on reducing pain and disability. However, previous studies have had methodological shortcomings including the use of outcome measures which do not accurately reflect program goals. Additionally, limited cost-effectiveness analyses have been undertaken and the cost-utility of the program has not been explored.

Methods/design: This study is a randomised controlled trial to determine the efficacy (in terms of Health-Related Quality of Life and self-management skills) and cost-utility of a 6-week group-based Stanford ASMP for people with hip or knee OA.

Six hundred participants referred to an orthopaedic surgeon or rheumatologist for hip or knee OA will be recruited from outpatient clinics at 2 public hospitals and community-based private practices within 2 private hospital settings in Victoria, Australia. Participants must be 18 years or over, fluent in English and able to attend ASMP sessions. Exclusion criteria include cognitive dysfunction, previous participation in self-management programs and placement on a waiting list for joint replacement surgery or scheduled joint replacement.

Eligible, consenting participants will be randomised to an intervention group (who receive the ASMP and an arthritis self-management book) or a control group (who receive the book only). Follow-up will be at 6 weeks, 3 months and 12 months using standardised self-report measures. The primary outcome is Health-Related Quality of Life at 12 months, measured using the Assessment of Quality of Life instrument. Secondary outcome measures include the Health Education Impact Questionnaire, Western Ontario and McMaster Universities Osteoarthritis Index (pain subscale and total scores), Kessler Psychological Distress Scale and the Hip and Knee Multi-Attribute Priority Tool. Cost-utility analyses will be undertaken using administrative records and self-report data. A subgroup of 100 participants will undergo qualitative interviews to explore the broader potential impacts of the ASMP.

Discussion: Using an innovative design combining both quantitative and qualitative components, this project will provide high quality data to facilitate evidence-based recommendations regarding the ASMP.

Severely compromised quality of life in women and those of lower socioeconomic status waiting for joint replacement surgery

Objective
To determine health-related quality of life (HRQOL), psychological distress, physical function, and self efficacy in persons waiting for lower-limb joint replacement surgery.

Methods
A total of 214 patients on a waiting list for unilateral primary total knee or hip replacement at a large Australian public teaching hospital completed questionnaires after entry to the list. HRQOL and psychological distress were compared with available population norms.

Results
Average HRQOL was extremely poor (mean ± SD 0.39 ± 0.24) and much lower (>2 SD) than the population norm. Near death-equivalent HRQOL or worse than death-equivalent HRQOL were reported by 15% of participants. High or very high psychological distress was up to 5 times more prevalent in the waiting list sample (relative risk 5.4 for participants ages 75 years and older; 95% confidence interval 3.3, 9.0). Women had significantly lower HRQOL, self efficacy, and physical function scores than men. After adjusting for age and sex, significant socioeconomic disparities were also found. Participants who received the lowest income had the poorest HRQOL; those with the least education or the lowest income had the highest psychological distress. Low self efficacy was moderately associated with poor HRQOL (r = 0.49, P < 0.001) and more strongly associated with high psychological distress (r = -0.55, P < 0.001).

Conclusion
Patients waiting for joint replacement have very poor HRQOL and high psychological distress, especially women and those from lower socioeconomic backgrounds. Lengthy waiting lists mean patients can experience extended and potentially avoidable morbidity. Interventions to address psychological distress and self efficacy could reduce this burden and should target women and lower socioeconomic groups.

Quality of life and depression among older patients waiting for joint replacement surgery

Purpose: Older patients waiting for joint replacement surgery in many western countries experience lengthy waits for their surgery. Although these patients suffer with mobility problems the nature of the disability associated with waiting for surgery is unclear. The purpose of this study was to determine health-related quality of life and symptoms of depression in persons waiting for their initial orthopaedic consultation following referral for total knee or total hip replacement surgery.

Methods: All patients who were waiting for an initial orthopaedic consultation for lower-limb joint replacement as at 25 August 2005 were surveyed. Participants were mailed questionnaires concerning demographic information, medical history, health-related quality of life (the Assessment of Quality of Life (AQoL) instrument), and symptoms of depression (Center for Epidemiologic Studies – Depression (CES-D) Scale).

Results: The 84 respondents (response rate 64%) had a mean age of 68.3 (SD 11.5 years), and 60% or respondents were women. Respondents reported an average of 1.6 (SD 0.9) medical conditions, and 85% reported osteoarthritis.} The average health-related quality of life was low (mean AQoL 0.38; SD 0.27), and near death-equivalent or worse than death-equivalent health-related quality of life (AQoL<0.1 of a maximum possible 1.0) was reported by 23% of the participants.The mean depression scale score was 16.5 (SD 11.1), and symptoms of depression (CES-D>16 of a maximum possible 60) were reported by 35% of the sample. There was a strong correlation between health-related quality of life and depression (r=–0.6).

Conclusions: Almost a third of patients waiting to see an orthopaedic surgeon about joint replacement surgery for their hip or knee had symptoms of depression. Geriatric rehabilitation services often provide interventions to these patients. The very poor quality of life reported suggests that more than exercise and strengthening will be needed to reduce disability.

Implementation of a quality care management system for patients with arthritis of the hip and knee

The Orthopaedic Unit of the Repatriation General Hospital (RGH) in Adelaide, South Australia has implemented a quality care management system for patients with arthritis of the hip and knee. The system not only optimises conservative management but ensures that joint replacement surgery is undertaken in an appropriate and timely manner. This new service model addresses identified barriers to service access and provides a comprehensive, coordinated strategy for patient management. Over 4 years the model has reduced waiting times for initial outpatient assessment from 8 to 3 months and surgery from 18 to 8 months, while decreasing length of stay from 6.3 to 5.3 days for hips and 5.8 to 5.3 days for knees. The service reforms have been accompanied by positive feedback from patients and referring general practitioners in relation to the improved coordination of care and enhanced efficiency in service delivery.

What is known about the topic? Several important initiatives both overseas and within Australia have contributed significantly to the development of this model of care. These include the UK National Health Service ‘18 weeks’ Project, the Western Canada Waiting List Project, the New Zealand priority criteria project, the Queensland Health Orthopaedic Physiotherapy Screening Clinic, and most importantly the Melbourne Health–University of Melbourne Orthopaedic Waiting List Project where a wide range of models were explored across Victorian hospitals from 2005 and the Multi-Attribute Prioritisation Tool (MAPT) was developed, validated and tested. This project became the Osteoarthritis Hip and Knee Service (OAHKS) and was operationalised in the Victorian healthcare system from 2012. These initiatives examined and addressed various aspects of management systems for patients with arthritis of the hip and knee in their particular setting.

What does this paper add? The development of this system is an extension of what is already known and is the first to encompass a comprehensive and coordinated strategy across all stages of the care management pathway for this patient group. Their management extends from the initial referral to development and implementation of a management plan, including surgery if assessed as necessary and organisation of long-term post operative follow up as required. By detailing the elements, key processes and measurable outcomes of the service redesign this paper provides a model for other institutions to implement a similar initiative.

What are the implications for practitioners? An important aspect of the design process was practitioner acceptance and engagement and the ability to improve their capacity to deliver services within an efficient and effective model. Intrinsic to the model’s development was assessment of practitioner satisfaction. Data obtained including practitioner surveys indicated an increased level of both satisfaction with the redesigned management service, and confidence in it to deliver its intended improvements.

Association between serum concentration of 25-hydroxyvitamin D and the risk of hip arthroplasty for osteoarthritis: result from a prospective cohort study

OBJECTIVES: There is ongoing debate regarding the optimal serum concentrations of 25-hydroxy-vitamin D for musculoskeletal health, including osteoarthritis (OA). The aim of this prospective cohort study was to determine whether serum 25-hydroxy-vitamin D concentrations were associated with the risk of hip arthroplasty for OA. DESIGN: This study examined 9135 participants from the Australian Diabetes, Obesity and Lifestyle Study who had serum 25-hydroxy-vitamin D measured in 1999-2000 and were aged ≥40 years at the commencement of arthroplasty data collection. The incidence of hip arthroplasty for OA during 2002-2011 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry. RESULTS: Over an average 9.1 (standard deviation (SD) 2.7) years of follow-up, 201 hip arthroplasties for OA were identified (males n = 90; females n = 111). In males, a one-standard-deviation increase in 25-hydroxy-vitamin D was associated with a 25% increased incidence (HR 1.25, 95% CI 1.02-1.56), with a dose response relationship evident by quartiles of 25-hydroxy-vitamin D concentration (P for trend 0.04). These results were independent of age, body mass index (BMI), ethnicity, smoking status, physical activity, season of blood collection, latitude, hypertension and diabetes, area level disadvantage or after excluding those with extreme low 25-hydroxy-vitamin D concentrations. No significant association was observed in women (HR 1.10, 95% CI 0.87, 1.39). CONCLUSIONS: Increasing serum 25-hydroxy-vitamin D concentrations were associated with an increased risk of hip arthroplasty for OA in males, while no significant association was observed in females. The mechanism for the association warrants further investigation.

First insight on the impact of an osteoblastic layer on the bio-tribocorrosion performance of Ti6Al4V hip implants

In uncemented Ti6Al4V hip implants, the bone-stem interface is subjected to cyclic loading motion driven by the daily activities of the patients, which may lead to the complete failure of the implant in the long term. It may also compromise the proliferation and differentiation processes of osteoblastic cells (bone-forming cells). The main objective of this work is to approach for the first time the role of these organic materials on the bio-tribocorrosion mechanisms of cultured Ti6Al4V alloys. The colonized materials with MG63 osteoblastic-like cells were characterized through cell viability/proliferation and enzymatic activity. Tribocorrosion tests were performed under a reciprocating sliding configuration and low contact pressure. Electrochemical techniques were used to measure the corrosion kinetics of the system, under free potential conditions. All tests were performed at a controlled atmosphere. The morphology and topography of the wear scar were evaluated. The results showed that the presence of an osteoblastic cell layer on the implant surface significantly influences the tribocorrosion behavior of Ti6Al4V alloy. It was concluded that the cellular material was able to form an extra protective layer that inhibits further wear degradation of the alloy and decreases its corrosion tendency.

Surgical dislocation of the hip for the fixation of acetabular fractures

Surgical dislocation of the hip in the treatment of acetabular fractures allows the femoral head to be safely displaced from the acetabulum. This permits full intra-articular acetabular and femoral inspection for the evaluation and potential treatment of cartilage lesions of the labrum and femoral head, reduction of the fracture under direct vision and avoidance of intra-articular penetration with hardware. We report 60 patients with selected types of acetabular fracture who were treated using this approach. Six were lost to follow-up and the remaining 54 were available for clinical and radiological review at a mean follow-up of 4.4 years (2 to 9). Substantial damage to the intra-articular cartilage was found in the anteromedial portion of the femoral head and the posterosuperior aspect of the acetabulum. Labral lesions were predominantly seen in the posterior acetabular area. Anatomical reduction was achieved in 50 hips (93%) which was considerably higher than that seen in previous reports. There were no cases of avascular necrosis. Four patients subsequently required total hip replacement. Good or excellent results were achieved in 44 hips (81.5%). The cumulative eight-year survivorship was 89.0% (95% confidence interval 84.5 to 94.1). Significant predictors of poor outcome were involvement of the acetabular dome and lesions of the femoral cartilage greater than grade 2. The functional mid-term results were better than those of previous reports. Surgical dislocation of the hip allows accurate reduction and a predictable mid-term outcome in the management of these difficult injuries without the risk of the development of avascular necrosis.

Obesity, age, sex, diagnosis, and fixation mode differently affect early cup failure in total hip arthroplasty: a matched case-control study of 4420 patients

Studies about the influence of patient characteristics on mechanical failure of cups in total hip replacement have applied different methodologies and revealed inconclusive results. The fixation mode has rarely been investigated. Therefore, we conducted a detailed analysis of the influence of patient characteristics and fixation mode on cup failure risks.