The impact of patellar resurfacing in two-stage revision of the infected total knee arthroplasty.

Evidence for optimal management of the patellofemoral joint in revision surgery for the infected TKA is limited. We reviewed 69 infected TKAs undergoing two-stage revision. Fifty four patellae were resurfaced, 11 had patelloplasty performed, two were augmented with trabecular metal, one had impaction grafting, and one knee underwent patellectomy. Average follow-up was 4.5 years. The patients that received patellar resurfacing at re-implantation experienced statistically significant improvements in KSS pain score, functional KSS, and patellar score (P < 0.03). One further patient treated with impaction grafting improved significantly in terms of pain and function. Patients treated with patelloplasty, trabecular metal augmentation, or patellectomy did not have significant improvements in clinical or functional outcome. Patient age, use of dynamic vs. static spacer, use of extensor mechanism release, and differences in Charlson index did not seem to statistically affect outcome. We recommend that every effort should be made to minimize patellar bone loss in first stage resection, as inability to resurface the patella at time of reimplantation may adversely affect patient outcome.

Local Validation of a National Orthopaedic Registry.

BACKGROUND/OBJECTIVE: Registries are limited by the quality of the data they collect. We aimed to measure the data entry error rate at a regional orthopaedic unit in a national arthroplasty registry and to assess a proposed intervention of restricting data entry to senior trainees. METHODS AND MATERIALS: A total of 200 primary and revision arthroplasty cases (119 hips, 81 knees) were randomly selected from a single year, 2020. The Irish National Orthopaedic Registry was examined for the grade of the trainee that populated the form and the accuracy of 24 parameters by comparison with data recorded elsewhere in the patient record. RESULTS: The mean number of errors per form was 2.17 (95% confidence interval (CI): 1.95-2.39), giving an overall error rate of 9% (95% CI: 8%-10.0%). Eighty-seven percent of forms examined contained inaccuracies, ranging from one to nine errors (4%-38%). Some parameters were more prone to errors, ranging from 1% to 28%. There was no evidence of total errors varying by trainee grade (analysis of variance (ANOVA) p-value: 0.34). CONCLUSIONS: Error rates were in line with the literature. Results did not support restricting data entry to senior trainees.

The utility of MRI scans for a painful knee in the elderly patient.

INTRODUCTION: We assess the requesting patterns and overall utility of MRI scans in our institution over a 6-month period for knee pain in an elderly population. METHODS: We performed a retrospective cohort study analysing patients undergoing a knee MRI between June 2018 and January 2019. Clinical notes were reviewed to determine the nature of any surgical intervention that was performed as a result of the MRI findings. A simple economic analysis was then performed using local pricing information. RESULTS: One hundred and nine MRI scans were performed. The majority of scans were ordered by primary care physicians with no preceding plain radiographs (55%, n = 60). Meniscal tears were reported in 68% of patients. Degenerative changes were noted in 82% of patients. One patient was noted to have a flipped meniscal fragment. This was the only patient to undergo surgical intervention of any kind. Univariate analysis demonstrated no correlation between the presence of a meniscal tear (p = 0.61) or degeneration (p = 0.56) and the need for intervention. The only significant predictor of intervention was the presence of locking (p < 0.001). For the 101 patients that underwent unnecessary MRI scans, our institution would have saved €17,170 in unnecessary costs over 6 months. CONCLUSION: We suggest that all elderly patients with knee pain undergo plain radiographs before MRI scan and only those with locking should be considered for an MRI scan at all. Primary care physicians are overusing MRI as an imaging modality in this cohort at a cost of over €30,000 per year to our institution.

Modeling the impact of obesity on cost of hip and knee arthroplasty.

PURPOSE: This study aimed to determine the proportions of total knee arthroplasty (TKA) and total hip arthroplasty (THA) attributable to obesity in Ireland and the associated hospital costs. METHODS: Sex- and age-specific numbers of primary TKA and THA procedures and length of stay were estimated using Irish population data from the Central Statistics Office (sex and age) and data from the national Hospital Inpatient Enquiry (numbers of TKA and THA procedures, length of stay, diagnostic-related group codes, sex, and age). Population attributable fractions of TKA and THA related to obesity were calculated using relative risks for different weight groups obtained from published literature. Nationally representative weight and height data were available from the 2015 Healthy Ireland Survey (n = 6142) and extrapolated to the Irish population. Diagnostic-related group tariffs from the Healthcare Pricing Office were used to estimate hospital costs of TKA and THA. RESULTS: In 2015, 2296 TKA and 3411 THA procedures were performed in public hospitals in Ireland. Of those procedures, 43% of TKA and 20% of THA were attributable to obesity. This equates to €16.0 million out of €52.1 million of TKA- and THA-related hospital costs. CONCLUSIONS: Effective obesity control has potential to decrease the demand for joint replacements and associated costs.

Midflexion Instability in Primary Total Knee Arthroplasty.

Instability is one of the most common causes of failure in total knee arthroplasty. Traditionally, it has been classified into three types: extension instability, flexion instability, and hyperextension instability. More recently, a fourth type of instability has been proposed, namely "midflexion instability" (MFI). Whether MFI is distinct from the aforementioned types of instability is contentious, and at present, the condition is yet to be clearly defined. This article reviews the current literature and identifies the best available evidence relevant to the concept of MFI. Our aim is to present an overview of the proposed causes and mechanisms for MFI. By doing so, we also aim to provide a focus on how MFI presents, whether it is indeed a discrete form of instability, and if it influences clinical results.

A prospective audit of blood usage post primary total knee arthroplasty.

The use of allogeneic blood is associated with many complications. A baseline audit performed in our institution in 2000 showed that 11% of patients undergoing primary total knee arthroplasty (TKA) required post-operative transfusion. Following this audit, patients undergoing primary TKA were no longer routinely cross matched, a Haemovigilance Nurse was employed in compliance with the National Blood Users Group guidelines, and post-operative cell salvage was introduced for patients with a preoperative haemoglobin level of less than 12 g/dl. A prospective audit was then performed over a nine month period, from 1st January to 30th September 2003, to assess the impact of these changes on our transfusion practice. Data was collected on 233 patients who had primary TKA performed during the period of our prospective audit. Patients were transfused if their blood loss exceeded a pre-calculated maximal allowable loss, or based on a 48 hour post-operative haemoglobin level. Seventeen of the 233 patients (7 %) received allogeneic blood. The average amount received was two units. Pre-operative anaemia and advanced patient age were predictive for increased risk of transfusion. Thirty six per cent of patients who were given a cell saver did not collect sufficient blood for re-transfusion. Ten per cent required further transfusion with allogeneic blood. There was no statistically significant difference in either the percentage of patients transfused or the volume of blood given to each patient between the two periods of audit. We did not find post-operative cell salvage to be an effective method of reducing allogeneic blood use.

Impact of Use of Intramedullary and Extramedullary Guides on Tibial Component Geometry in Total Knee Replacements: A Systematic Review and Meta-Analysis.

Mechanical guides in total knee arthroplasty are divided into intramedullary and extramedullary systems, designed to give accurate reference, to enable the surgeon to perform a tibial cut which is perpendicular to the mechanical axis. We conducted a systematic review and meta-analysis of levels 1 and 2 published data which directly compares the two methods of alignment, with outcomes of interest being the mean tibial component angle to the mechanical axis and the number of outliers from the optimal range. The PRISMA (preferred reporting items for systematic reviews and meta-analysis) guidance was followed. A search was conducted of online databases Medline PubMed; EMBASE; ISI Web of Science, and the Cochrane library, using the Boolean search string ([intramedullary OR extramedullary] AND knee AND [arthroplasty OR replacement]). Numerical data pertaining to tibial component alignment (TCA), the mechanical tibiofemoral angle, the tibial slope, and the number of outliers from optimal TCA were collated, and used to establish pooled results. No constraints on the search in terms of year of publication or language were instituted. Intrastudy bias was assessed using the Jadad score for randomized controlled trials and the Newcastle Ottawa score for prospective cohort studies. A total of 1,896 titles were reviewed. Following abstract review and full review of relevant articles, 10 publications were included for analysis, of which 8 were suitable to include for meta-analysis. No trials showed a significant difference in the mean TCA. Two trials showed an increased number of outliers in the extramedullary group and two studies showed an increased number of outliers in the intramedullary group. Pooled data from studies which included these outcomes showed no advantage for either system in limiting the number of outliers from the optimal TCA (relative risk, 0.99; 95% confidence interval [CI], 0.87-1.14; p = 0.004), and no significant difference in mean TCA (standardized mean difference, -0.07; 95% CI, -0.22 to 0.08; p = 0.000). Based on our results, no advantage can be attributed to the type of mechanical guide used in obtaining an adequate tibial cut.

Day of Surgery Admission in Total Joint Arthroplasty: Why Are Surgeries Cancelled? An Analysis of 3195 Planned Procedures and 114 Cancellations.

Background. Day of surgery admission (DOSA) is becoming standard practice as a means of reducing cost in total joint arthroplasty. Aims. The aim of our study was to audit the use of DOSA in a specialty hospital and identify reasons for cancellation. Methods. A retrospective study of patients presenting for hip or knee arthroplasty between 2008 and 2013 was performed. All patients were assessed at the preoperative assessment clinic (PAC). Results. Of 3195 patients deemed fit for surgery, 114 patients (3.5%) had their surgery cancelled. Ninety-two cancellations (80%) were due to the patient being deemed medically unsuitable for surgery by the anaesthetist. Cardiac disease was the most common reason for cancellation (n = 27), followed by pulmonary disease (n = 22). 77 patients (67.5%) had their operation rescheduled and successfully performed in our institution at a later date. Conclusion. DOSA is associated with a low rate of cancellations on the day of surgery. Patients with cardiorespiratory comorbidities are at greatest risk of cancellation.

Surgical hip dislocation does not result in atrophy or fatty infiltration of periarticular hip muscles.

Surgical hip dislocation is the gold standard for treatment of femoroacetabular impingement (FAI). It utilizes an intermuscular and internervous approach to the hip. Concerns have been expressed that this approach causes soft tissue trauma resulting in post-operative muscle weakness of patients undergoing this procedure. We therefore asked whether surgical hip dislocation leads to (i) atrophy (decreased muscle diameter or cross-sectional area [CSA]) and (ii) degeneration (fatty infiltration) of 18 evaluated periarticular hip muscles. We retrospectively evaluated 32 patients (34 hips) following surgical hip dislocation for the treatment of FAI using pre and post-operative magnetic resonance (MR) arthrography of the hip. We evaluated muscle diameter, CSA and degree of fatty infiltration according to Goutallier for 18 periarticular hip muscles on axial and sagittal views. The mean interval between pre and post-operative MR was 1.9 ± 1.5 years (range, 0.4-6.1 years). Pre and post-operative muscle diameter and CSA of all 18 evaluated hip muscles did not differ. There was no post-operative change in the Goutallier classification for any of the evaluated 18 muscles. No muscle had post-operative degeneration higher than Grade 1 according to Goutallier. No atrophy or degeneration of periarticular hip muscles could be found following surgical hip dislocation for treatment of FAI. Any raised concerns about the invasiveness and potential muscle trauma for this type of surgery are unfounded. Level III, retrospective comparative study. See guidelines for authors for a complete description of levels of evidence.

Anti-biofilm activity of sub-inhibitory povidone-iodine concentrations against Staphylococcus epidermidis and Staphylococcus aureus.

Biomaterial-related infections continue to hamper the success of reconstructive and arthroplasty procedures in orthopaedic surgery. Staphylococci are the most common etiologic agents, with biofilm formation representing a major virulence factor. Biofilms increase bacterial resistance to antimicrobial agents and host immune responses. In staphylococci, production of polysaccharide intercellular adhesin (PIA) by the enzyme products of the icaADBC operon is the best understood mechanism of biofilm development, making the ica genes a potential target for biofilm inhibitors. In this study we report that the antibacterial agent povidone-iodine (PI) also has anti-biofilm activity against Staphylococcus epidermidis and Staphylococcus aureus at sub-inhibitory concentrations (p < 0.001). Inhibition of biofilm by PI correlated with decreased transcription of the icaADBC operon, which in turn correlated with activation of the icaR transcriptional repressor in Staphylococcus epidermidis. These data reveal an additional therapeutic benefit of PI and suggest that studies to evaluate suitability of PI as biomaterial coating agent to reduce device-related infections are merited.

The use of locking plates in proximal humeral fractures: Comparison of outcome by patient age and fracture pattern.

PURPOSE: This study was undertaken to evaluate the efficacy of a proximal humeral locking plate, and to specifically study the effect of patient age and fracture type on the outcome. MATERIALS AND METHODS: Thirty-one cases of proximal humeral fractures fixed by using the proximal humeral interlocking (PHILOS) plate were reviewed. RESULTS: Average functional scores (minimum 18 months post operation) per AO / ASIF fracture type were 25.3 for type A, 21.4 for type B, and 22.7 for type C. There was no statistically significant difference between the groups. The functional scores for patients over 65 years of age were significantly inferior (P = 0.03). At a final radiological review (mean 12 months post operation), 30 (96%) of the patients demonstrated fracture union. Seven patients (22.5%) required a second surgical procedure. CONCLUSION: We obtained both good functional results and bone healing with the PHILOS plate, irrespective of fracture type; the older patients had a poorer outcome. We caution the surgeons on the high potential for reoperations with its use.

Hydrogen peroxide induced repression of icaADBC transcription and biofilm development in Staphylococcus epidermidis.

Expression of the icaADBC-encoded polysaccharide intercellular adhesion by Staphylococcus epidermidis promotes biofilm formation and represents an important virulence factor in biomaterial-related infections following orthopedic surgery. Biofilm development by the pathogen can be viewed as a protective reaction to environmental stressors including osmotic stress, thermal stress, and antimicrobial chemotherapy. Oxidative stress, arising from the release of toxic oxygen radicals by polymorphonuclear cells, is encountered by bacteria entering the body perioperatively. Evasion of this and other cell-mediated immune responses by pathogenic bacteria plays an important role in the development of chronic biomaterial-related infection. Here we investigated the impact of sublethal oxidative stress induced by H2O2 (<18 mM) on S. epidermidis biofilm formation. S. epidermidis grown in brain heart infusion (BHI) media supplemented with 5 mM H2O2 or 10 mM H2O2 formed significantly less biofilm (p < 0.01 and p < 0.001, respectively) than bacteria grown in BHI alone. Consistent with this, using reverse transcription-polymerase chain reaction expression of the ica locus was also shown to be reduced by subinhibitory concentrations of H2O2. Furthermore, diminished ica operon expression correlated with increased expression of icaR, which encodes a repressor of icaADBC. Thus, these data suggest that mild oxidative stress downregulates biofilm development by S. epidermidis and may have potential in a therapeutic context.

Heelys and street gliders injuries: a new type of pediatric injury.

OBJECTIVES: Our goals were to highlight an increasing trend in orthopedic injuries in children as a result of "heeling" or "street gliding," to describe injuries sustained by children using Heelys (HSL, Carrollton, TX) and Street Gliders (Glowgadgets Ltd, Bristol, United Kingdom), and to increase public awareness and prevent such injuries. PATIENTS AND METHODS: We prospectively recorded the data of all roller shoes injuries referred to our department during the summer school holiday. Using a data-collection sheet, we recorded demographic data, type of injury, mechanism and place of injury, heeling or street-gliding experience, use of safety equipment, methods of treatment, and intention to continue heeling or street gliding after recovery from injury. RESULTS: Over a 10-week period, 67 children suffered orthopedic injuries while using Heelys or Street Gliders. There were 56 girls and 11 boys with a mean age of 9.6 years. Upper limbs were the most common location of injury. Distal radius fractures were the most prevalent, followed by supracondylar fractures, elbow dislocations, and hand fractures. The majority of children suffered the injury while heeling or street gliding outdoors. Interestingly, 20% of the injuries happened while trying Heelys or Street Gliders for the first time, and 36% of the injuries occurred while learning (using 1-5 times) how to use them. None of the children used any sort of protective gear at the time of the injury. The majority of the injured children expressed their intention to continue heeling or street gliding after complete recovery from their injury. CONCLUSIONS: Our study shows that the majority of children with injuries from heeling or street gliding are girls. We recommend close supervision of children using Heelys or Street Gliders during the steep learning curve and usage of protective gear at all times. These new types of injuries have a serious impact on child health and constitute a burden for the pediatric orthopedic service.