Aims. Metal allergy in knee arthroplasty patients is a controversial topic. We aimed to conduct a scoping review to clarify the management of metal allergy in primary and revision total knee arthroplasty (TKA). Methods. Studies were identified by searching electronic databases: Cochrane Central Register of Controlled Trials, Ovid MEDLINE, and Embase, from their inception to November 2020, for studies evaluating TKA patients with metal hypersensitivity/allergy. All studies reporting on diagnosing or managing metal hypersensitivity in TKA were included. Data were extracted and summarized based on study design, study population, interventions and outcomes. A practical guide is then formulated based on the available evidence. Results. We included 38 heterogeneous studies (two randomized controlled trials, six comparative studies, 19 case series, and 11 case reports). The evidence indicates that metal hypersensitivity is a rare complication with some histopathological features leading to pain and dissatisfaction with no reliable screening tests preoperatively. Hypoallergenic implants are viable alternatives for patients with self-reported/confirmed metal hypersensitivity if declared preoperatively; however, concerns remain over their long-term outcomes with ceramic implants outperforming titanium nitride-coated implants and informed consent is paramount. For patients presenting with painful TKA, metal hypersensitivity is a diagnosis of exclusion where patch skin testing, lymphocyte transformation test, and synovial biopsies are useful adjuncts before revision surgery is undertaken to hypoallergenic implants with shared decision-making and informed consent. Conclusion. Using the limited available evidence in the literature, we provide a practical approach to metal hypersensitivity in TKA patients. Future national/registry-based studies are needed to identify the scale of metal hypersensitivity, agreed diagnostic criteria, and management strategies. Cite this article: Bone Jt Open 2021;2(10):785–795

Background: Metal sensitivity following total joint arthroplasty (TJA) has been of increased concern, but the impact of a patient-reported metal allergy on clinical outcomes has not been investigated. The purpose of this study was to report the incidence and impact of patient-reported metal allergy following total knee (TKA) and total hip arthroplasty (THA). Methods: This was a retrospective, IRB-approved investigation of patients undergoing a primary, elective TJA between 2009 and 2011. All patients completed a pre-operative questionnaire asking about drug and environmental allergies. In January of 2010, a specific question was added regarding the presence of a metal allergy. UCLA Activity, SF-12, Modified Harris Hip (MHHS), and Knee Society (KSS) scores were collected pre-operatively and at most recent follow-up. Overall cohorts of metal allergy and non-metal allergy patients were compared and a 1:2 matching analysis was also performed. Results: 906 primary THAs and 589 primary TKAs were included. The incidence of patient-reported metal allergy was 1.7% before January 2010 and 4.0% after (overall 2.3% of THAs and 4.1% of TKAs). 97.8% of metal allergy patients were female. Following TKA, post-operative KSS function, symptoms, satisfaction, and expectation scores were all decreased in the metal allergy cohort (p<0.001 to 0.002). Following THA, metal allergy patients had a decreased post-operative SF-12 MCS score and less incremental improvement in their SF-12 MCS score versus the non-metal allergy cohort (p<0.0001 and p<0.001). Conclusion: Patient-reported metal allergy is associated with decreased functional outcomes following TKA and decreased mental health scores following THA

Introduction. While prosthesis survival in Total Knee Arthroplasty (TKA) exceeds 90% at 10 year, failures do occur. One area of concern has been the potential for metal allergy or metal sensitivity causing persistent pain, swelling or early failure of the implant in some patients. Definitive tests for diagnosing metal allergy and metal sensitivity have not been developed and this field remains controversial. In most cases where metal sensitivity is a concern, metals such as Chromium and Nickel are implicated. Despite the lack of good diagnostic tests for identifying these patients, several orthopedic prosthesis manufacturers have developed implants made of Titanium or ceramic designed for use in patients where concerns exist regarding metal allergy. In the absence of good diagnostic tests, use of these devices in patients that self identify is one option. To date, little information has been presented about the incidence of self reported metal sensitivity in patients undergoing joint replacement. This study was undertaken to determine the incidence of self reported metal allergy or sensitivity in patients undergoing total knee arthroplasty. Methods. An IRB approved, retrospective chart review was performed in a consecutive series of 194 patients who had undergone TKA at one institution, with one surgeon. Self reported metal sensitivity and allergy had been routinely elicited from each individual who had not undergone implantation of a previous metallic device, during pre-operative consultation. Results. 36 of the 194 patients had a previously well functioning implanted metal device. In addition, data was missing in 19 patients. Therefore, data from 139 out of 158 consecutive patients who had no prior implanted metal devices was available. 20 of 139 patients (14%) reported a known metal allergy or sensitivity. This included 19 of 86 females (22%) and 1 of 53 males (2%). This difference was statistically significant (P=0.001). Conclusions. If self reported prior metal sensitivity or allergy is used to guide prosthesis selection in TKA, approximately 14% of patients would be candidates for “hypo-allergenic” prostheses. If only particular sizes of components are offered in these alternative materials, smaller sizes or female gender specific sizes should be considered due to the higher incidence of self reported metal allergies in female patients

It is estimated that 15 % of the population is allergic to metal, most commonly to Nickel, which is a common component of the alloys in most knee and hip arthroplasties. It would therefore be expected that allergy to metal is a frequent form of implant failure – but very little is reported in the literature. With the recent concerns about metal-on-metal bearings and metal ion issues, there has been renewed interest in metal allergy – with the Australian Joint Registry 2010 reporting it as a causative factor in 7 % of Hip Resurfacing revisions. With over 200 BHR and 571 ASR Hip Resurfacing arthroplasties in my series from 2001, I have identified only 1 patient with implant failure due to metal allergy. In 2010 two Total Knee Arthroplasty patients presented with pain and strongly positive Melisa allergy tests – these patients were revised to Titanium coated implants resulting in a complete relief of symptoms. This paper will analyse the problem of metal sensitivity, the investigation and management of the allergic patient who has, or requires, joint arthroplasty

Aims: Palacos cement is one of the commonest types of bone cements used in joint replacement surgery. It contains peanut oil which is used as a diluent for Chlorophyll to give the green colour. The manufacturer’s instruction states that it is a contra-indication to use Palacos cement in patients allergic to peanut. The aim of our study was to check the awareness among the orthopaedic surgeons of this contra-indication and find their views on using Palacos cement in patients allergic to peanuts. Methods: We conducted a postal questionnaire survey among all the orthopaedic surgeons and trainees in Wales, enquiring about their prior knowledge of the contra-indication and their views on what should be done if the patient undergoing arthroplasty has peanut allergy. Results: There was a response rate of 71%. Only 20% of the consultants and only 40% of the trainees were aware of the contraindication. There were widely conflicting views on what should be done if the patient has peanut allergy. Those views included using different cement, using uncemented implant, seeking second opinion and some suggested they would still continue to use Palacos cement despite history of peanut allergy. Conclusions: Majority of the orthopaedic surgeons in our study were not aware of the contraindication. This is surprising as peanut allergy could be life threatening. But we are unaware of any reported case of allergic reaction in peanut allergic patients. Review of the literature also suggests that as the peanut oil in Palacos cement is highly refined peanut oil, it is very unlikely to produce allergic reaction in peanut allergic patients. There is no evidence-based reason to support the manufacturer’s advice that Palacos cement should not be used in patients allergic to peanuts

Introduction. First generation cephalosporins remain the gold standard perioperative antibiotic for total hip and knee arthroplasty (THA, TKA). However, some patients have documented or self-reported allergies to antibiotics, most commonly penicillin, that result in changes to perioperative antibiotic coverage. Furthermore, patients testing positive for methicillin resistant staphylococcus aureus (MRSA) represent another group where an alternative to cefazolin, typically vancomycin, is often chosen for perioperative prophylaxis. The aims of this study were to 1) characterize the antibiotic choices for perioperative prophylaxis at the time of primary TKA and THA, 2) assess the efficacy of a preoperative antibiotic allergy testing program, and 3) determine rates of periprosthetic joint infection (PJI) based on perioperative antibiotic regimen. Methods. We evaluated all patients undergoing primary TKA or THA at a single academic institution from January 2004-May 2017, yielding a cohort of 29,695 patients. A series of institutional databases were combined to determine which patients underwent antibiotic allergy testing prior to surgery, outcomes from the allergy consultation, perioperative antibiotic management strategy, and survivorship free of infection until final follow-up. Results. Antibiotic allergy testing was performed in 3,411 patients (11.5%) on the basis of a patient provided history of possible penicillin or cephalosporin allergy. Among those tested, 3,310 patients (97.0%) were cleared by the allergist to use cephalosporins in the perioperative period and 2,883 patients (87.1%) eventually received cefazolin. For the entire cohort, 28,174 patients (94.9%) received an operative antibiotic regimen including cefazolin and 1,521 patients (5.1%) received non-cefazolin antibiotics, most commonly vancomycin or clindamycin. Survivorship free of PJI was significantly higher among patients receiving cefazolin compared to non-cefazolin antibiotics with the most rapid divergence occurring within 2 months of surgery (p<0.001) (Figure 1). Survivorship free of PJI in the cefazolin compared to the non-cefazolin groups was 99.40% vs 99.34% at 1 month, 99.11% vs 98.55% at 2 months, 98.83% vs 98.22% at 1 year, and 98.15% vs 96.96% at 10 years (Table 1). Notably, the increased PJI rate observed in the non-cefazolin group was not attributable to high preoperative MRSA prevalence as 0 of the 38 PJIs grew MRSA on culture. The number needed to treat with cefazolin to prevent 1 PJI was 164 patients at 1-year and 84 patients at 10-years. Therefore, potentially 6,098 PJIs could be prevented by 1-year and 11,905 by 10-years in a cohort of 1,000,000 primary TKA and THA patients. Conclusions. This study demonstrates a significantly higher rate of PJI when non-cefazolin antibiotics are used for prophylaxis during primary TKA and THA, which is likely attributable to the superior spectrum of coverage for common PJI organisms compared to vancomycin or clindamycin. This is supported by the increased rate of non-MRSA PJI observed in the non-cefazolin cohort. Furthermore, cefazolin has been shown to act synergistically with vancomycin against MRSA. This work highlights the positive impact of a formal preoperative antibiotic allergy testing program to increase cefazolin usage. Also, surgeons may consider using cefazolin as a dual agent in the case of known MRSA colonization, whenever possible for PJI prophylaxis during TKA and THA. For any figures or tables, please contact authors directly

Perioperative antibiotic prophylaxis remains one of the most important strategies for prevention of periprosthetic joint infection (PJI) with current guideline recommending a first or second generation cephalosporin. Penicillin (PCN) allergy is often reported by patients, which often results in avoidance of administration of cephalosporins due to fear of cross-reactivity. Alternative medications, such as vancomyin, are often used despite reduced antimicrobial coverage. The purpose of this study was to determine if PCN allergic patients who received vancomycin alone prior to elective primary total joint arthroplasty were at increased risk of developing a subsequent PJI. A retrospective review of 7,602 primary total joint arthroplasties (TJAs) performed between 2005 and 2013 in two institutions were identified using a prospective institutional database. Patient reported PCN or cephalosporin allergy was electronically queried from the anesthesia note. Patients who recieved multiple prophylactic antibiotics, or had unavailable perioperative antibiotic information, or those who received medication other than cefazolin and vancomycin were excluded. PJI was determined using a cross-match with an institutional PJI database constructed from International Classification of Diseases (ICD)-9 codes. Logistic regression analysis was then performed to evaluate the risk of subsequent PJI. The rate of PJI was 1.4% (32/2296) in patients with a reported PCN allergy that received vancomycin alone versus 1.1% (59/5306) in non-PCN allergic patients that received cefazolin alone. The multivariate analysis, with the given sample size, did not detect a statistically significant increased risk of PJI when vancomycin was administered alone (adjusted odds ratio: 1.23, 95% CI 0.6–3.1, p=0.35). While there was no significant differences in the organism profile between PJIs in both groups, the rate of PJI caused by resistant organisms was higher in patients who received vancomycin alone (11.9%, 7/59) compared to those who received cefazolin (3.1%, 1/32). While administration of perioperative prophylactic vancomycin alone during elective primary arthroplasty does not seem to result in a higher rate of subsequent PJI, patients who received vancomycin alone and developed a PJI were more likely to develop an infection with an antibiotic resistant organism. Future studies are needed to determine the most appropriate prophylactic antibiotic for patients who undergo elective arthroplasty and report PCN allergy

Summary Statement. Routine metal allergy screening prior to joint arthroplasty is not essential and the use of cobalt chromium or stainless steel implants is recommended regardless of the patient's metal allergy status. Introduction. This study was undertaken to obtain a consensus amongst joint arthroplasty experts with regards to metal allergy screening prior to joint arthroplasty and the choice of implant in patients with potential metal allergy. Patients & Methods. A web based Delphi consensus study was used including orthopaedic surgeons that had previously published on the topic of knee, hip or shoulder arthroplasty. Two rounds of questionnaires were sent via electronic mail. Consensus was considered if agreement was 60% or higher. Results. 18 surgeons responded to the first and 17 to the second round of questionnaires. There was consensus that patients having metal arthroplasty surgery should not be routinely questioned about metal allergy prior to surgery. There was consensus that patch testing is not necessary even if metal allergy is suspected. Most respondents agreed in proceeding with cobalt chromium or stainless steel implant in patients suspected of metal allergy regardless of the results of cutaneous patch testing. Discussion/Conclusion. This consensus study suggests that routine metal allergy screening prior to joint arthroplasty is not essential. The use of traditional cobalt chromium/stainless steel implants is recommended regardless of the patient's metal allergy status

Introduction. There has been much controversy around metal on metal hip replacements of late due to adverse metal reactions. There is evidence implicating lymphocyte mediated response (type IV delayed-hypersensitivity) to metal debris generated by the implants as one of the main factors responsible for the reactions. Our understanding of these adverse reactions continues to improve but we also recognize that the majority of patients with MOM implants are asymptomatic with well functioning implants. Studies have shown up to 16% allergy to metal ions on pre-operative allergy patch testing. We set out to determine the incidence of hypersensitivity to Cobalt, Chromium and Molybdenum in a arthroplasty population. Method. We assayed whole blood using a validated optimized lymphocyte transformation test, MELISA as part of a prospective randomized study on large diameter bearing surfaces. We recruited 47 subjects, 19 males, 28 females (35–75 yrs). Specific exclusions included presence of metal implants in the body and industrial exposure to metals. Results. Results were available for 46 patients. Four patients (9%) demonstrated hypersensitivity to Cobalt and none to Chromium or Molybdenum. Two were female and two male. The result was weakly positive in three patients and strongly positive in one female. Conclusion. Hypersensitivity in patients without prior exposure to Cobalt, Chromium and Molybdenum is low. The relevance of a positive hypersensitivity test and implications on the choice of bearings is a subject that requires further research. NO DISCLOSURES

Aims. Despite recent literature questioning their use, vancomycin and clindamycin often substitute cefazolin as the preoperative antibiotic prophylaxis in primary total knee arthroplasty (TKA), especially in the setting of documented allergy to penicillin. Topical povidone-iodine lavage and vancomycin powder (VIP) are adjuncts that may further broaden antimicrobial coverage, and have shown some promise in recent investigations. The purpose of this study, therefore, is to compare the risk of acute periprosthetic joint infection (PJI) in primary TKA patients who received cefazolin and VIP to those who received a non-cephalosporin alternative and VIP. Methods. This was a retrospective cohort study of 11,550 primary TKAs performed at an orthopaedic hospital between 2013 and 2019. The primary outcome was PJI occurring within 90 days of surgery. Patients were stratified into two groups (cefazolin vs non-cephalosporin) based on their preoperative antibiotic. All patients also received the VIP protocol at wound closure. Bivariate and multiple logistic regression analyses were performed to control for potential confounders and identify the odds ratio of PJI. Results. In all, 10,484 knees (90.8%) received cefazolin, while 1,066 knees (9.2%) received a non-cephalosporin agent (either vancomycin or clindamycin) as preoperative prophylaxis. The rate of PJI in the cefazolin group (0.5%; 48/10,484) was significantly lower than the rate of PJI in the non-cephalosporin group (1.0%; 11/1,066) (p = 0.012). After controlling for confounding variables, the odds ratio (OR) of developing a PJI was increased in the non-cephalosporin cohort compared to the cefazolin cohort (OR 2.389; 1.2 to 4.6); p = 0.01). Conclusion. Despite the use of topical irrigant solutions and addition of local antimicrobial agents, the use of a non-cephalosporin perioperative antibiotic continues to be associated with a greater risk of TKA PJI compared to cefazolin. Strategies that increase the proportion of patients receiving cefazolin rather than non-cephalosporin alternatives must be emphasized. Cite this article: Bone Jt Open 2022;3(1):35–41

Metal-on-metal articulations are increasingly used in THR. Hypersensitivity reactions to the metal ions can occur. The symptoms and signs are similar to a patient presenting with an infected prosthesis. Correct diagnosis before revision surgery is crucial to implant selection and operation planning. We present a practical approach to this diagnostic problem. The history, clinical findings, hip scores, radiology, serum metal ions, ESR, C-RP, hip arthroscopy and aspirate results, synovial fluid metal ion levels, labelled white cell/colloid scan, 99m-technetium scan, revision hip findings and histology of a typical patient who had an allergic response to a metal-on-metal hip articulation are presented, and how the findings differ from a patient with an infected implant. Clinical examination, hip scores and serum metal ion levels were repeated one year after revision of the metal-on-metal hip articulation to a ceramic-on-ceramic. In hypersensitivity, the periarticular tissues undergo lymphocyte-dominated infiltration, the histology differs from that found in infection. The white cell labelled/colloid scan also uses this difference for diagnosis. Hip aspiration is the single best investigation for infection. Conclusion: There is no single investigation available in most hospitals that will reliably differentiate infection from allergy in the painful THR. Hip aspiration, labelled white cell/colloid scan and histology obtained from hip arthroscopy biopsy are the most useful investigations

In a randomized study of 60 patients allergic reactions are evaluated in three joint prosthesis groups, a resurfacing arthroplasty (ReCap), a non-cemented, large metal-on-metal head (Bimetric Magnum) and a non-cemented, alumina ceramic-on-ceramic bearing in a titanium shell (Bimetric C2a).

The inclusion criteria were osteoarthritis, ASA I–II, MRI-scan without caput necrosis, DXA-scan without osteoporosis. The exclusion criteria were short neck (<2cm.), large cysts (>1cm.), medical treatment affecting the bone metabolism, severe deformity of the femoral head, impaired kidney function and inability to co-operate.

Blood samples were drawn prior to and 6 weeks, 6 months, 1 year, and 3 years after surgery; two tubes from which plasma was prepared, and two tubes for serum. From the last included 20 patients in each group was also taken blood one and three years after surgery for an in vitro lymphocyte assay for scoring of possible hypersensitivity to prosthesis metals. The isolated lymphocytes were subjected to measurement of proliferation and expression of CD69 by flow cytometry and measurement of the Migration Inhibitory Factor (MIF) by ELISA. Plasma concentrations of the cytokines IL-1, IL-4, IL-6, IL-8, IL-12p70, IL-15, interferon-and osteoprotegerin were determined by multiplex-immunoassay. Serum concentrations of chromium and cobalt were determined by graphite furnace atomic absorption spectrometry.

The serum concentrations of chromium and cobalt were lowest in patients with the C2a implant and highest with Magnum, some of these differences were significant at 6 weeks, 6 months, and 1 year after surgery. No patient had a very high serum metal concentration. The values of the variables measured in the in vitro lymphocyte assay mainly changed in the expected direction depending on the concentration of the same metal in the serum sample drawn at the same time, but no significant correlation was seen. One patient had uncertain symptoms of metal hypersensitivity and relatively high serum metal concentrations 3 years after arthroplasty with a Magnum prosthesis and was assessed extraordinarily, and elicited the marginally highest MIF responses in the lymphocyte assay. A strong correlation was found between the plasma concentrations of most cytokines, but the cytokine concentrations were not correlated to contemporary metal concentrations.

Abstract. Introduction. The aims of our systematic review were to assess the Nickel sensitising potential of total knee arthroplasty (TKA), explore the relationship between Nickel hypersensitivity and clinical outcomes, and evaluate the utility of skin patch testing pre- and/or post-operatively. Methodology. A literature search was performed through EMBASE, Medline and PubMed databases. Articles were screened independently by two investigators. Levels of Evidence were assessed using Oxford CEBM criteria and quality was assessed using MINORS and Cochrane risk-of-bias tools. Results. Twenty studies met the eligibility criteria, reporting on 1354 TKAs. Prevalence of Nickel hypersensitivity ranged from 0% to 87.5%. Only one study which compared prevalence of hypersensitivity in the same patient group before and after surgery noted newly positive patch test reactions in 4.1%. Three studies reported lower prevalence of hypersensitivity in post-operative patients compared to pre-operative patients. Seven studies suggested hypersensitivity might cause complications; six studies did not support any relationship. Seven studies recommended pre-operative patch testing in patients with history of metal allergy; nine studies concluded testing may be valuable post-operatively. Conclusions. Patients undergoing TKA do not seem to be at increased risk of developing Nickel hypersensitivity, and there is conflicting evidence that patients with established hypersensitivity are more likely to experience adverse clinical outcomes. The evidence suggests performing patch testing pre-operatively in patients with history of metal allergy to aid selection of the most appropriate prosthesis, and post-operatively once common causes of implant failure have been excluded, since implant removal or revision with hypoallergenic implants may alleviate symptoms

The role of metal sensitivity or allergy in causing persistent symptoms or failure and need for a revision of a total joint replacement has been the topic of debate and controversy for decades. There was renewed interest in this area with the rise of metal-on-metal hip arthroplasty and the advent of adverse local tissue reactions. This led to an increase in metal ion testing as well as metal sensitivity testing. With the decline of the use of metal-on-metal hip components, this is now mostly an issue in knee arthroplasty. It is well known that a substantial percentage of patients have persistent symptoms following knee replacement. What remains in question is whether allergy to metal or other materials such as PMMA may be a contributing factor. It is accepted that the incidence of positive skin patch tests is higher in symptomatic failed joint replacements. Nickel sensitivity is most common as a positive skin test with up to 15% of patients demonstrating this followed by chromium and cobalt. A recent review by Lachiewicz et al. concluded that there was insufficient evidence to recommend routine or widespread cutaneous or in vitro hypersensitivity testing before primary TKA, that there is no evidence-based rationale to recommend a routine metal allergy screening questionnaire, that there is only anecdotal support for Ni-free implants, and that local dermatitis should be treated with topical steroids. In another article, routine screening for metal allergy was not recommended, however, selective screening for history of sensitivity or unexplained pain or early loosening was suggested. Other experts have recommended a role for utilizing a commercially available alternative to components containing nickel or cobalt in patients thought to be hypersensitive. A recent study, however, concluded that there was no difference in complications, revisions, or reoperations among patients who tested positive with patch testing whether they were treated with standard components or nickel free components. Likewise, a consensus panel published results from the United Kingdom in which cobalt chrome implants were recommended regardless of the patients metal allergy status. Patient perception is important, however, and among patients who report multiple allergies of any kind, a higher percentage are likely to be dissatisfied with their knee replacement. Of more importance are those reporting a specific allergy to metal are substantially more likely to express some dissatisfaction with their components. Metal allergy as a cause of chronic pain and/or early failure of joint replacement is rare if it exists at all. It is always a diagnosis of exclusion. Patients who think they are allergic are probably more likely to be more symptomatic following joint replacement. Whether or not to use a nickel free or hypoallergenic component in such patients remains an area of controversy

Currently, there is considerable interest in the role that metal allergy may play in the clinical performance of orthopaedic devices. The extant literature suggests that metal allergy is a real clinical phenomenon, albeit the prevalence and clinical impact are not defined. Degradation products in the form of ionic or particulate debris can complex with local proteins and alter their conformation so that they may not be recognised as self-proteins. This can result in an adaptive immune response. The typical paradigm proposed for such an allergy is that of a delayed type hypersensitivity response (Type 4) whereby the antigenic stimulus interacts with antigen presenting cells and T lymphocytes to elicit a cell mediated immune response. There is some evidence that patients with metal-on-metal bearings and/or high serum metal levels elicit more response to metal antigen challenge measured as either patch test sensitivity or lymphocyte proliferation. Thus, while there is an idiosyncratic aspect of the allergic response, there is also a dose response component. The diagnosis of metal allergy remains a challenge as patch testing has not been shown to correlate well with clinical symptoms. In-vitro assays, such as lymphocyte transformation testing, have promise but await robust clinical validation before they can be considered reliable diagnostic testing modalities. Allergy to implanted metal orthopaedic devices is a rare clinical event, and is a diagnosis of exclusion. Revision surgery should be considered a last resort with the understanding that the outcomes are unpredictable. Given the limitations of current diagnostic modalities, widespread screening of patients for metal allergies prior to TKA is not recommended

To compare the efficacy of intra-articular and intravenous modes of administration of tranexamic acid in primary total knee arthroplasty in terms of blood loss and fall in haemoglobin level. Study Design: Randomized controlled trial. Duration of Study: Six months, from May 2019 to Nov 2019. Seventy-eight patients were included in the study. All patients undergoing unilateral primary total knee replacement were included in the study. Exclusion criteria were patients with hepatitis B and C, history of previous knee replacement, bilateral total knee replacement, allergy to TXA, Hb less than 11g/dl in males and less than 10g/dl in females, renal dysfunction, use of anticoagulants for 7 days prior to surgery and history of thromboembolic diseases. Patients were randomly divided into group A and B. Group A patients undergoing unilateral primary total knee replacement (TKR) were given intravenous tranexamic acid (TXA) while group B were infiltrated with intra-articular TXA. Volume of drain output, fall in haemoglobin (Hb) level and need for blood transfusion were measured immediately after surgery and at 12 and 24 hours post operatively in both groups. The study included 35 (44.87%) male and 43 (55.13%) female patients. Mean age of patients was 61 ± 6.59 years. The mean drain output calculated immediately after surgery in group A was 45.38 ± 20.75 ml compared with 47.95 ± 23.86 ml in group B (p=0.73). At 24 hours post operatively, mean drain output was 263.21 ± 38.50 ml in intravenous group versus 243.59 ± 70.73 ml in intra-articular group (p=0.46). Regarding fall in Hb level, both groups showed no significant difference (p>0.05). About 12.82% (n=5) patients in group A compared to 10.26% (n=4) patients required blood transfusion post operatively (p=0.72). Intra-articular and intravenous TXA are equally effective in patients undergoing primary total knee arthroplasty in reducing post-operative blood loss

Our knowledge of primary bone marrow edema (BME) of the knee is still limited. A major contributing factor is that it shares several radiological findings with a number of vascular, traumatic, and inflammatory conditions having different histopathological features and etiologies. BME can be primary or secondary. The most commonly associated conditions are osteonecrosis, osteochondritis dissecans, complex regional pain syndrome, mechanical strain such as bone contusion/bruising, micro-fracture, stress fracture, osteoarthritis, and tumor. The etiology and pathogenesis of primary BME are unclear. Conservative treatment includes analgesics, non-steroidal anti-inflammatory drugs, weight-bearing limitations, physiotherapy, pulsed electromagnetic fields, prostacyclin, and bisphosphonates. Surgical treatment, with simple perforation, fragment stabilization, combined scraping and perforation, and eventually osteochondral or chondrocyte transplant, is reserved for the late stages. This retrospective study of a cohort of patients with primary BME of the knee was undertaken to describe their clinical and demographic characteristics, identify possible risk factors, and assess treatment outcomes. We reviewed the records of 48 patients with primary BME of the knee diagnosed on MRI by two radiologists and two orthopedists. History, medications, pain type, leisure activities, smoking habits, allergies, and environmental factors were examined. Analysis of patients’ characteristics highlighted that slightly overweight middle-aged female smokers with a sedentary lifestyle are the typical patients with primary BME of the knee. In all patients, the chief symptom was intractable day and night pain (mean value, 8.5/10 on the numerical rating scale) with active as well as passive movement, regardless of BME extent. Half of the patients suffered from thyroid disorders; indeed, the probability of having a thyroid disorder was higher in our patients than in two unselected groups of patients, one referred to our orthopedic center (odds ratio, 18.5) and another suffering from no knee conditions (odds ratio, 9.8). Before pain onset, 56.3% of our cohort had experienced a stressful event (mourning, dismissal from work, concern related to the COVID-19 pandemic). After conservative treatment, despite the clinical improvement and edema resolution on MRI, 93.8% of patients described two new symptoms: a burning sensation in the region of the former edema and a reduced ipsilateral patellar reflex. These data suggest that even though the primary BME did resolve on MRI, the knee did not achieve full healing

Aim. Deep infection following endoprosthetic replacement (EPR) of long bones is a devastating complication occurring in 15% of musculoskeletal tumour patients. The recently published PARITY Trial demonstrated that extending antibiotic prophylaxis from 24 hours to 5 days does not reduce infection rates. However, questions remain about the optimal antibiotic choice and dose. Method. A 23-question multiple-choice questionnaire was designed and piloted through an iterative feedback process until the final version was agreed by all authors. Open and closed-ended questions were used to gather information on practice and Likert-type scale responses were used to grade responses to ascertain surgeon perceptions and preferences. The online survey was sent to all surgeon delegates of the 34th Annual Meeting of the European Musculo-Skeletal Oncology Society in London in October 2022. Results. Amongst 61 respondents, 43 were based in Europe and 18 outside of Europe. The majority (48/61) had been in clinical practice over 11 years. Antibiotic choice. 1st or 2nd generation cephalosporins were the first line choice practiced among 49 (80.3%) of respondents. Of these, 39 responded had a 2nd line protocol for beta-lactam allergy which was most commonly clindamycin (18), vancomycin (11) or a combination of a glycopeptide or clindamycin plus gentamicin (4). Respondents changed their first line regimen for radiotherapy in 6/61, chemotherapy in 8/61 and tumour site in 20/61. Re-dosing. Intraoperative re-dosing intervals of 1st and 2nd generation cephalosporins ranged from 2 to 8 hourly. Re-dosing for blood loss ranged from never to when 2 litres was lost. Of the 47 respondents, 24 said intraoperative re-dosing is always reliably administered. Duration. Six (10%) of 61 respondent routinely cover the intraoperative period only, whereas 30 (49%) give 24 hours, 16 (give 48 hours or longer and 8 continue until surgical drains are removed. 31 of 61 change duration depending on clinical situation. The most common reasons for changing were patient risk factors, soft tissue status and previous radiotherapy. 57/61 surgeons were aware of the PARITY Trial. When these respondents were asked whether they had changed practice based on PARITY, 12 said yes, 24 said no and 21 said they always give 24 hours anyway. Conclusions. Amongst an international cohort of orthopaedic oncology surgeons there was a wide variation in practice. Further research should focus on the optimum choice and re-dosing strategy, which have not been defined

Aim. Swedish guidelines on antibiotic prophylaxis in arthroplasty surgery recommend cloxacillin in fixed doses that pay little attention to the patient's renal function and weight. Nevertheless, there are no studies on whether the resulting free prophylactic cloxacillin in vivo concentrations are optimal. We aimed to evaluate whether the current recommended prophylactic dosage of cloxacillin is adequate. Method. We performed a prospective two-centre study, measuring the free (active) cloxacillin concentrations in plasma throughout surgery, in patients subject to primary hip and knee prosthetic joint replacements, aiming at 100 patients per centre. To account for plasma-bone exposure differences, concentrations were considered adequate if twice the epidemiological cut-off value for cloxacillin concerning wild type Staphylococcus aureus whereas two-three times were labelled threshold values. The two enrolling hospitals are acute care hospitals in central Sweden, also performing 600 - 1200 primary hip and knee joint arthroplasties annually. All patients scheduled for elective primary hip or knee replacements from January 2022 to April 2024 were eligible for participation. Exclusion criteria were allergy towards penicillins, cognitive disorders leading to inability to sign informed consent, and an absence of interpreter in case of a patient not speaking Swedish or English. Results. We present results from the first 49 patients included. Four patients had free cloxacillin concentrations below cut-off (8.2%). These four cases had prolonged surgeries of 77-100 minutes. An additional 5/49 (10.2%) had threshold values. Conversely 5/49 (10.2%) cases had concentrations exceeding 15 times the needed. No cases with threshold or low cloxacillin concentrations were attributable to a lack of concerning timing and dosing of cloxacillin. All concentrations were above or equal to our cut-off at the start of surgery. Eighteen percent of patients were of normal of weight (BMI 18.5- 25). Of the rest 4% were morbidly obese (BMI >40), 41% obese (BMI 30-40) and 37% overweight (BMI 25-30). Twenty seven percent (43/159) had diabetes and 45% suffered cardiac disease. Conclusions. Some patients in our cohort had insufficient active cloxacillin levels at the end of prosthetic joint surgery. Previous studies indicate that insufficient prophylactic antibiotic concentrations might lead to an enhanced risk of prosthetic joint infections. Other patients were massively overdosed, leading to unnecessary ecological effects and potentially adverse reactions. As inadequate cloxacillin concentrations were not associated with a lack of compliance to current guidelines a change in practise might be needed. Our final results may help to determine how dosing should be adjusted

On hundred and ninety unselected patients, mean age 62(SD12.8) were operated upon by one surgeon, using same approach. HSS improved from 33 to 75 post-operatively, the low figures reflecting a high percentage of Charnley C patients (71%). There was a 5% mortality rate from unrelated causes. Early complications included a 2.97% femoral fracture rate within 4–8 weeks of surgery (analysis showed no relation between implant position, BMI, age or Charnley classification, but there was correlation between high level of satisfaction and early weight bearing). There was one infection and one dislocation. Late complications included 3 periprosthetic fractures, 3 dislocations and 2 aseptic cup failures. However, 30% of patients developed groin pain, increasing stiffness and clunking at 1–2 years following surgery. These patients were investigated with an ultrasound scan. 28 patients (14%) had an effusion and were aspirated. Chrome and cobalt levels in synovial fluid, blood and urine were very high. 13 patients have been revised. 1 showed infection, 10 showed metal allergy and 2 a mixed picture of allergy and foreign body reaction. In our MOM database (762 hips including the current study) a total of 35 patients were revised for similar problems. Two distinct histological finding were observed. Metal allergy occurred independently of cup angle. The implants were well fixed; there was tissue necrosis and histological evidence of ALVAL. There was no infection or metalosis. FB reaction occurred more frequently when the cup was open. The Implants were loose; there was naked eye evidence of metalosis and metallic particles seen on light microscopy. We concluded that Birmingham/Freeman Hybrid had high complication rate without significant functional superiority, and other MoM devises shared similar complication. Both Metal allergy and FB reaction can occur in MOM THR. Ultra sound is a good screening tool in symptomatic patients