Abstract. Background. The incidence of periprosthetic fractures of the femur around a total knee arthroplasty (TKA) is rising and this is owed to the increased longevity that today's TKA implants allow for, as well as an aging population. These injuries are significant as they are related to increased morbidity and mortality. Methods. We retrospectively reviewed all periprosthetic fractures around a TKA that presented to our NHS Trust between 2011 to 2020. Medical records were reviewed. Treatment, complications and mortality were noted. Results. 37 patients (34 females) with an average age of 84 (range 65–99) met the inclusion criteria for this study. 17 patients (45.9%) underwent open reduction and internal fixation (ORIF), eight patients (21.6%) underwent revision arthroplasty to a distal femoral replacement (DFR) and 12 patients (32.4%) were treated non-operatively. 10 (58.8%) of the 17 patients that were treated with ORIF were discharged from hospital to a rehabilitation facility rather than their usual residence. In comparison, 3 (37.5%) of the patients that were treated with a DFR were discharged to a rehabilitation facility. one-year mortality rate in the ORIF group was 29.4 compared to 12.5% in those that had a DFR. Conclusion. Revision arthroplasty using a DFR should be considered in patients with periprosthetic fractures around a TKR, as it is associated with lower mortality rates and higher immediate post-operative function

Abstract. Introduction. Revision total knee arthroplasty (RTKA) is a complex procedure with higher rates of re-revision, complications and mortality compared to primary TKA. We report the effects of the establishment of a Revision Arthroplasty Network (The East Midlands Specialist Orthopaedic Network; EMSON). Methodology. The Revision Arthroplasty Network was established in January 2015 and covered the Nottinghamshire and Lincolnshire areas of England. This comprises a collaborative weekly multidisciplinary meeting where upcoming RTKA procedures are discussed, and a plan agreed. Using the Hospital Episode Statistics database, RTKA procedures carried out between 2011 and 2018 from the five EMSON hospitals were compared to all other hospitals in England. Age, sex, and Hospital Frailty Risk scores were used as covariates. The primary outcome was re-revision surgery within 1 year of the index revision. Secondary outcomes were re-revision surgery within two years, any complication within one and two years and median length of stay. Results. 33,828 RTKA procedures were performed across England; 1,028 (3.0%) were conducted within EMSON. Re-revision rates within 1 year were 11.6% and 7.4% pre- and post-intervention respectively within the network. This compares to a pre-post change from 11.7% to 9.7% for the rest of England. In comparative interrupted time-series analysis, there was a significant immediate improvement in re-revision rates for EMSON hospitals compared to the rest of England at 1 year (p = 0.024) and 2 years (p=0.032). Conclusion. Re-revision rates for RTKA improved significantly at one and two years with the introduction of EMSON, when compared to the rest of England

Aims

The aim of this study was to evaluate the ability of a machine-learning algorithm to diagnose prosthetic loosening from preoperative radiographs and to investigate the inputs that might improve its performance.

The aim of this study was to determine the mid-term survival and functional outcomes of the Scorpio Total Stabilised Revision Knee prosthesis. Sixty seven prostheses were implanted between November 2001 and April 2008. 42 females and 23 males. Average patient age was 67.9 (37-89). Outcomes were assessed with WOMAC (Western Ontario and McMaster Universities Osteoarthritis index), Knee Society Scores, Short Form-8 scores, patient satisfaction and radiological review. Average follow-up was over 3 years (8-93mths) with 95% follow-up. One patient died post operatively and 4 patients from 18 months to 5 years post-operatively. Average body mass index was 32.9 (21.5- 55.1). 65% (42 patients) of patients operated on had a Body Mass Index of greater than 30. 48 patients were ASA 3 or greater. Thirteen second stage revision arthroplasties were performed after treatment for infected arthroplasty surgery. Twenty six prostheses were revised for aseptic loosening. Eight prostheses were revised for stiffness and 9 for worn polyethylene inserts. Five prostheses were revised for symptomatic tibio-femoral instability/ dislocation and one for patello-femoral instability. Two revisions were performed for peri-prosthetic fractures and 2 for previously operated tibial plateau fractures. Seven patients required tibial tubercle osteotomy and seven a rectus snip. Thirty one patients had greater than a 15mm polyethylene insert. The average KSS increased from 49 pre-operatively to 64 at 7.5 years. The average KS function score increased from 21 to 45. 68% (44) of patients had other significant joint involvement which affected daily function. 24% of patients were unsatisfied with the outcome. 89.5% of patients radiographs were assessed for loosening or subsidence. 51% of femoral components and 36% of tibial components had radiosclerotic lines. The surface area of each implant including the stem was measured on antero-posterior and lateral images. The degree of lucency was calculated as a percentage and in mm from the component. Two prostheses (3%) were revised for deep infection, one (1.5%) for stiffness and one for aseptic loosening (1.5%). Complications included a popliteal artery injury, two superficial wound infections, and one patella tendon avulsion. Survival rate for revision of prosthesis was 87% at 7.5 years and 90% excluding infection. Success of second stage revision arthroplasty after treatment of infection was 92%

Aims. To compare rates of serious adverse events in patients undergoing revision knee arthroplasty with consideration of the indication for revision (urgent versus elective indications), and compare these with primary arthroplasty and re-revision arthroplasty. Methods. Patients undergoing primary knee arthroplasty were identified in the national Hospital Episode Statistics (HES) between 1 April 1997 to 31 March 2017. Subsequent revision and re-revision arthroplasty procedures in the same patients and same knee were identified. The primary outcome was 90-day mortality and a logistic regression model was used to investigate factors associated with 90-day mortality and secondary adverse outcomes, including infection (undergoing surgery), pulmonary embolism, myocardial infarction, and stroke. Urgent indications for revision arthroplasty were defined as infection or fracture, and all other indications (e.g. loosening, instability, wear) were included in the elective indications cohort. Results. A total of 939,021 primary knee arthroplasty procedures were included (939,021 patients), of which 40,854 underwent subsequent revision arthroplasty, and 9,100 underwent re-revision arthroplasty. Revision surgery for elective indications was associated with a 90-day rate of mortality of 0.44% (135/30,826; 95% confidence interval (CI) 0.37 to 0.52) which was comparable to primary knee arthroplasty (0.46%; 4,292/939,021; 95% CI 0.44 to 0.47). Revision arthroplasty for infection was associated with a much higher mortality of 2.04% (184/9037; 95% CI 1.75 to 2.35; odds ratio (OR) 3.54; 95% CI 2.81 to 4.46), as was revision for periprosthetic fracture at 5.25% (52/991; 95% CI 3.94 to 6.82; OR 6.23; 95% CI 4.39 to 8.85). Higher rates of pulmonary embolism, myocardial infarction, and stroke were also observed in the infection and fracture cohort. Conclusion. Patients undergoing revision arthroplasty for urgent indications (infection or fracture) are at higher risk of mortality and serious adverse events in comparison to primary knee arthroplasty and revision arthroplasty for elective indications. These findings will be important for patient consent and shared decision-making and should inform service design for this patient cohort. Cite this article: Bone Joint J 2021;103-B(10):1578–1585

Abstract. Introduction. The objective of this study was to determine rates of serious adverse events in patients undergoing revision knee arthroplasty with consideration of the indication for revision and compare these with primary knee arthroplasty. Methodology. Primary and revision arthroplasty procedures were identified in the national Hospital Episode Statistics and were linked by patient and side. A logistic regression model was used to investigate factors associated with 90-day mortality (primary outcome) and secondary serious adverse outcomes. Urgent indications for revision arthroplasty were defined as infection or fracture; other indications (e.g. loosening, instability, wear) were included in the elective cohort. Results. 939,021 primary knee arthroplasty and 40,584 revision cases were included. Revision surgery for elective indications was associated with a 90-day rate of mortality of 0.44% (95% CI 0.37-0.52) which was comparable to primary knee arthroplasty (0.46%; 95% CI 0.44-0.47). Revision arthroplasty for infection, however, was associated with a much higher mortality of 2.04% (95% CI 1.75-2.35; odds ratio [OR] 3.54; 95% CI 2.81-4.46), as was revision for periprosthetic fracture at 5.25% (95% CI 3.94-6.82; OR 6.23; 95% CI 4.39-8.85). Higher rates of PE, MI, and stroke were observed in the infection and fracture cohort. Conclusion. Patients presenting with infection of a knee arthroplasty or a periprosthetic fracture are at very high risk of adverse events. It is important that acute hospital services and tertiary referral centres caring for these patients are appropriately supported to ensure appropriate urgency with an anticipation for increased care requirements

Aims. Periprosthetic fractures (PPFs) around the knee are challenging injuries. This study aims to describe the characteristics of knee PPFs and the impact of patient demographics, fracture types, and management modalities on in-hospital mortality. Methods. Using a multicentre study design, independent of registry data, we included adult patients sustaining a PPF around a knee arthroplasty between 1 January 2010 and 31 December 2019. Univariate, then multivariable, logistic regression analyses were performed to study the impact of patient, fracture, and treatment on mortality. Results. Out of a total of 1,667 patients in the PPF study database, 420 patients were included. The in-hospital mortality rate was 6.4%. Multivariable analyses suggested that American Society of Anesthesiologists (ASA) grade, history of peripheral vascular disease (PVD), history of rheumatic disease, fracture around a loose implant, and cerebrovascular accident (CVA) during hospital stay were each independently associated with mortality. Each point increase in ASA grade independently correlated with a four-fold greater mortality risk (odds ratio (OR) 4.1 (95% confidence interval (CI) 1.19 to 14.06); p = 0.026). Patients with PVD have a nine-fold increase in mortality risk (OR 9.1 (95% CI 1.25 to 66.47); p = 0.030) and patients with rheumatic disease have a 6.8-fold increase in mortality risk (OR 6.8 (95% CI 1.32 to 34.68); p = 0.022). Patients with a fracture around a loose implant (Unified Classification System (UCS) B2) have a 20-fold increase in mortality, compared to UCS A1 (OR 20.9 (95% CI 1.61 to 271.38); p = 0.020). Mode of management was not a significant predictor of mortality. Patients managed with revision arthroplasty had a significantly longer length of stay (median 16 days; p = 0.029) and higher rates of return to theatre, compared to patients treated nonoperatively or with fixation. Conclusion. The mortality rate in PPFs around the knee is similar to that for native distal femur and neck of femur fragility fractures. Patients with certain modifiable risk factors should be optimized. A national PPF database and standardized management guidelines are currently required to understand these complex injuries and to improve patient outcomes. Cite this article: Bone Joint J 2024;106-B(2):158–165

Aims. Fungal periprosthetic joint infections (PJIs) are rare, but their diagnosis and treatment are highly challenging. The purpose of this study was to investigate the clinical outcomes of patients with fungal PJIs treated with two-stage exchange knee arthroplasty combined with prolonged antifungal therapy. Methods. We reviewed our institutional joint arthroplasty database and identified 41 patients diagnosed with fungal PJIs and treated with two-stage exchange arthroplasty after primary total knee arthroplasty (TKA) between January 2001 and December 2020, and compared them with those who had non-fungal PJIs during the same period. After propensity score matching based on age, sex, BMI, American Society of Anesthesiologists grade, and Charlson Comorbidity Index, 40 patients in each group were successfully matched. The surgical and antimicrobial treatment, patient demographic and clinical characteristics, recurrent infections, survival rates, and relevant risk factors that affected joint survivorship were analyzed. We defined treatment success as a well-functioning arthroplasty without any signs of a PJI, and without antimicrobial suppression, at a minimum follow-up of two years from the time of reimplantation. Results. The fungal PJI group demonstrated a significantly worse treatment success rate at the final follow-up than the non-fungal PJI group (65.0% (26/40) vs 85.0% (34/40); p < 0.001). The mean prosthesis-free interval was longer in the fungal PJI group than in the non-fungal PJI group (6.7 weeks (SD 5.8) vs 4.1 weeks (SD 2.5); p = 0.020). The rate of survivorship free from reinfection was worse in the fungal PJI group (83.4% (95% confidence interval (CI) 64.1 to 92.9) at one year and 76.4% (95% CI 52.4 to 89.4) at two years) than in the non-fungal PJI group (97.4% (95% CI 82.7 to 99.6) at one year and 90.3% (95% CI 72.2 to 96.9) at two years), but the differences were not significant (p = 0.270). Cox proportional hazard regression analysis identified the duration of the prosthesis-free interval as a potential risk factor for failure (hazard ratio 1.128 (95% CI 1.003 to 1.268); p = 0.043). Conclusion. Fungal PJIs had a lower treatment success rate than non-fungal PJIs despite two-stage revision arthroplasty and appropriate antifungal treatment. Our findings highlight the need for further developments in treating fungal PJIs. Cite this article: Bone Joint J 2023;105-B(12):1286–1293

Abstract. Introduction. In revision knee arthroplasty, rotating hinge implants (RHK) have been considered to result in higher complication rates and lower survivorship when compared to constrained condylar implants (CCK). The aims of this study were to compare patient reported outcome measures (PROMs), complication rates and survivorship of RHK and CCK used in revision arthroplasty at a single, high volume elective orthopaedic centre with previously validated bespoke database. Methodology. One hundred and eight patients who underwent revision knee arthroplasty with either CCK or RHK and matched our inclusion criteria were identified. EQ5D, Health State and Oxford Knee Scores were collected pre-operatively and at 1 year post-operatively. Complication data was collected at 6 weeks, 6 months, 1 year and 2 years post-operatively. NJR data was interrogated, in addition to our own database, to investigate implant survival. Results. There was no statistically significant difference between RHK and CCK in implant survival at two to twelve years of follow up. In addition, we observed no statistically significant difference in the PROMs scores and complication rates of the two implants. Conclusion. This study shows that both the RHK and CCK remain viable options in revision arthroplasty, the implant survival and complication rate were comparable. We recommend prospective randomised control trials with long-term follow up to further investigate the use of CCK and RHK implants in revision knee arthroplasty

Abstract. Introduction. The prevalence of recurrent infection following two-stage exchange arthroplasty following failure of a total knee arthroplasty (TKA) has been reported to be 10% to 25%. There is limited literature available on repeat two stage revisions for TKA infection with only small cohorts and variable success rates. Methodology. A retrospective cohort study investigating the outcome of two stage revision arthroplasty for treatment of TKA infection was conducted with the aim of identifying factors linked to recurrence of infection. A consecutive cohort of all microbiology intra-operative periprosthetic knee samples from a single revision arthroplasty centre between January 2010 and December 2016 was identified. The final cohort consisted of 658 samples taken during 64 patients undergoing two stage revision knee surgery for infection. Patient demographics, medical and orthopaedic history data including post-operative outcomes and subsequent treatment was obtained from the electronic records system and medical notes. Results. 65.6% of the cohort (N=42) had successful eradication of their infection. For the twenty-two patients that had failure of their two stage revision, twenty patients had samples available from further surgical intervention. Sixteen patients (80%) had different organisms isolated when they had repeat surgical samples taken when compared to their first stage samples. Overall, for subsequent treatments there was a success rate of 75% if the same organism was identified and 62.5% if there were new isolated organisms. Conclusion. These findings may have implications for the treatment strategies chosen for re-infection after two stage TKA revisions if new causative organisms are isolated

Aims. The mean age of patients undergoing total knee arthroplasty (TKA) has reduced with time. Younger patients have increased expectations following TKA. Aseptic loosening of the tibial component is the most common cause of failure of TKA in the UK. Interest in cementless TKA has re-emerged due to its encouraging results in the younger patient population. We review a large series of tantalum trabecular metal cementless implants in patients who are at the highest risk of revision surgery. Methods. A total of 454 consecutive patients who underwent cementless TKA between August 2004 and December 2021 were reviewed. The mean follow-up was ten years. Plain radiographs were analyzed for radiolucent lines. Patients who underwent revision TKA were recorded, and the cause for revision was determined. Data from the National Joint Registry for England, Wales, Northern Island, the Isle of Man and the States of Guernsey (NJR) were compared with our series. Results. No patients in our series had evidence of radiolucent lines on their latest radiological assessment. Only eight patients out of 454 required revision arthroplasty, and none of these revisions were indicated for aseptic loosening of the tibial baseplate. When compared to data from the NJR annual report, Kaplan-Meier estimates from our series (2.94 (95% confidence interval (CI) 1.24 to 5.87)) show a significant reduction in cumulative estimates of revision compared to all cemented (4.82 (95% CI 4.69 to 4.96)) or cementless TKA (5.65 (95% CI 5.23 to 6.10)). Our data (2.94 (95% CI 1.24 to 5.87)) also show lower cumulative revision rates compared to the most popular implant (PFC Sigma Cemented Knee implant fixation, 4.03 (95% CI 3.75 to 4.33)). The prosthesis time revision rate (PTIR) estimates for our series (2.07 (95% CI 0.95 to 3.83)) were lower than those of cemented cases (4.53 (95% CI 4.49 to 4.57)) from NJR. Conclusion. The NexGen trabecular (tantalum) cementless implant has lower revision rates in our series compared to all cemented implants and other types of cementless implants, and its use in younger patients should be encouraged. Cite this article: Bone Jt Open 2024;5(4):277–285

Abstract. Multidisciplinary team (MDT) meetings in orthopaedic surgery are evolving. The goals include patient optimisation, surgical planning and discharge arrangements, individually on a patient specific basis. In line with British Association Surgery of the Knee and GIRFT guidelines, we report our regional experience on the implementation and evolution of our regional Revision Knee Arthroplasty MDT. We undertook a retrospective review of the process, cases discussed and quality assurance conducted in the weekly MDT. Since implementation of the MDT meeting in January 2019, 550 patients with painful joint replacements have been discussed. In May 2021, we formalised our ‘terms of reference’ and ‘standard operating procedures’ which are adhered to by the consultants operating within the network, all of whom attend the meeting. A proforma has been developed and is completed for all cases capturing all pertinent information. All cases are graded according to R1, R2, or R3 complexity scale. Since its inception, the MDT has looked at all post-operative imaging, we now describe a new classification system for grading the appearances. Confirmation of the pre-operative plan and actual surgical intervention is reviewed and audited. In addition, confirmation of indication of revision at the time of operation is reviewed and validated for accuracy with benefits to the unit, individual surgeon and the NJR. In conclusion, the implementation of the revision MDT facilitating pre-operative revision arthroplasty discussion and post-operative quality assurance processes enable surgeons to educate, reflect on their practice and ensure that the highest standards of care are being provided

Abstract. Introduction. Inter-prosthetic femoral fractures (IPFF) are fractures occurring between ipsilateral hip and knee implants or fixation devices. In 2020, the National Hip Fracture Database (NHFD) was extended to capture data from patients with peri-prosthetic femoral fractures (PPFF), including those specifically with IPFF. This study aims to describe the epidemiology and treatment of IPFF in England and Wales. Methodology. This population-based observational cohort study utilised open-access data available from the NHFD. Patients aged over 60, admitted to an acute hospital in England or Wales with an IPFF, within the period 1st January 2020 to 31st December 2020 were included. The primary outcome of this study was the incidence of IPFF in England and Wales. The secondary outcome was the treatment received. Results. Of 2606 patients admitted with PPFF, a total of 133 fractures occurred between ipsilateral hip and knee implants. Internal fixation was performed most frequently, in 87 cases. Revision arthroplasty was performed in 15 cases (hip n=10, knee n=5). A total of 20 patients were managed non-operatively, and three underwent primary arthroplasty (hip n=2, knee n=1). Conclusion. As the proportion of patients living with hip and knee implants continues to increase, it is expected that so too will the incidence of IPFF. This study is the first to estimate the incidence of IPFF in England and Wales. This is likely an underestimate of the true incidence and so we support calls for the prioritisation of further research into the epidemiology, prevention, and management of IPFF

Aims. The management of periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is challenging. The correct antibiotic management remains elusive due to differences in epidemiology and resistance between countries, and reports in the literature. Before the efficacy of surgical treatment is investigated, it is crucial to analyze the bacterial strains causing PJI, especially for patients in whom no organisms are grown. Methods. A review of all revision TKAs which were undertaken between 2006 and 2018 in a tertiary referral centre was performed, including all those meeting the consensus criteria for PJI, in which organisms were identified. Using a cluster analysis, three chronological time periods were created. We then evaluated the antibiotic resistance of the identified bacteria between these three clusters and the effectiveness of our antibiotic regime. Results. We identified 129 PJIs with 161 culture identified bacteria in 97 patients. Coagulase-negative staphylococci (CNS) were identified in 46.6% cultures, followed by Staphylococcus aureus in 19.8%. The overall resistance to antibiotics did not increase significantly during the study period (p = 0.454). However, CNS resistance to teicoplanin (p < 0.001), fosfomycin (p = 0.016), and tetracycline (p = 0.014) increased significantly. Vancomycin had an 84.4% overall sensitivity and 100% CNS sensitivity and was the most effective agent. Conclusion. Although we were unable to show an overall increase in antibiotic resistance in organisms that cause PJI after TKA during the study period, this was not true for CNS. It is concerning that resistance of CNS to new antibiotics, but not vancomycin, has increased in a little more than a decade. Our findings suggest that referral centres should continuously monitor their bacteriological analyses, as these have significant implications for prophylactic treatment in both primary arthroplasty and revision arthroplasty for PJI. Cite this article: Bone Joint J 2021;103-B(6 Supple A):171–176

Abstract. Introduction. In 2020, the National Hip Fracture Database (NHFD) was extended to capture data from patients with periprosthetic femoral fractures (PPFF) with plans to include these patients in Best Practice Tarif. We aimed to describe the epidemiology of PPFF in England and Wales, with a particular focus on fractures occurring around the femoral component of knee prostheses. Methodology. This population-based observational cohort study utilised open-access data available from the NHFD. Patients aged over 60, admitted to an acute hospital in England or Wales with a PPFF, within the period 1st January 2020 to 31st December 2020 were included. The primary outcome was the incidence of PPFF in England and Wales. The secondary outcome was the treatment received. Results. We identified 2606 patients with PPFF from 135 hospitals. Of these, a total of 578 fractures occurred around the femoral component of a knee implant. These were classified as Vancouver A (epicondylar, n=77), B (involving implant/cement, n=166) and C (proximal to implant/cement, n=335). Internal fixation was the most employed treatment, used in 352 cases. Revision arthroplasty was performed in 80 cases, and 100 were managed non-operatively. Only 28% of operated PPFF went to theatre within 36 hours but nearly 90% had orthogeriatrician review within 72 hours. Conclusion. Eighty six percent of patients with PPFF were treated with non-revision surgery and would not be recorded in the National Joint Registry. In response, we support calls for the prioritisation of further research into the prevention and management of PPFF around the knee

Abstract. Introduction. Knee arthrodesis is one of the treatment options for limb salvage of a failed total knee replacement (TKR) when further revisions were contraindicated. The aim of this study is to determine patient outcomes after knee arthrodesis (KA) following a failed TKR. Methodology. A literature search was conducted for studies published from January 2000 through January 2022 via Medline, Web of Science, Embase and Cochrane databases. Only primary research studies were included with independent extraction of articles by two reviewers. Results were synthesised by narrative review according to PRISMA guidelines, with full tabulation of all included study results. Results. A total of 34 studies with 1,034 patients were included in the review; all were longitudinal observational studies, and none were conducted as randomised controlled trials. Reporting methods were very inconsistent in the included studies, and this heterogeneity led to pooled data totals that varied widely in different categories. The mean follow-up was 3.5 years. Overall, 72.0% (167 of 232) of patients used a walking stick and 12.5% (36 of 287) remained non-ambulatory after KA. Only 7.7% (58 of 752) of patients subsequently underwent above-knee amputation. Conclusion. KA is a potential limb salvage procedure after revision arthroplasties have been attempted in cases of failed TKR. Most patients were able to ambulate both at home and in the community, although with an increased rate of using a walking stick after the operation. However, in the absence of randomised controlled trials, these data may allow for a more accurate counselling and decision making

Aims. Revision total knee arthroplasty (rTKA) accounts for approximately 5% to 10% of all TKAs. Although the complexity of these procedures is well recognized, few investigators have evaluated the cost and value-added with the implementation of a dedicated revision arthroplasty service. The aim of the present study is to compare and contrast surgeon productivity in several differing models of activity. Materials and Methods. All patients that underwent primary or revision TKA from January 2016 to June 2018 were included as the primary source of data. All rTKA patients were categorized by the number of components revised (e.g. liner exchange, two or more components). Three models were used to assess the potential surgical productivity of a dedicated rTKA service : 1) work relative value unit (RVU) versus mean surgical time; 2) primary TKA with a single operating theatre (OT) versus rTKA with a single OT; and 3) primary TKA with two OTs versus rTKA with a single OT. Results. In total, 4570 procedures were performed: 4128 primary TKAs, 51 TKA liner exchanges, and 391 full rTKAs. Surgical time was significantly different between the primary TKA, liner exchange, and rTKA cohorts (100.6, 97.1, and 141.7 minutes, respectively; p < 0.001). Primary TKA yielded a mean of 7.1% more RVU/min per procedure than rTKA. Our one-OT model demonstrated that primary TKA (n = 4) had a 1.9% RVU/day advantage over rTKA (n = 3). If two OTs are used for primary TKA (n = 6), the outcome strongly favours primary TKA by an added 34.6% RVUs/day. Conclusion. Our results suggest that a dedicated rTKA service would lead to lower surgeon remuneration based on the current RVU paradigm. Revision arthroplasty specialists may need additional or alternative incentives to promote the development of a dedicated revision service. Through such an approach, healthcare organizations could enhance the quality of care provided, but surgeon productivity measures would need to be adjusted to reflect the burden of these cases. Cite this article: Bone Joint J 2019;101-B:675–681

Introduction. Despite several preventive strategies, periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) is still a devastating complication. Early diagnosis and appropriate treatment are crucial to achieve successful infection control, but challenging since there is no test with 100% sensitivity and 100%. Therefore, several national and international guidelines include synovial analysis of joint aspirates as important diagnostic criteria, but cut-off levels for synovial cell count (CC) and polymorphonuclear (granulocyte) percentage (PMN%) are still debatable. The current investigation was performed to analyze the overall accuracy and optimal cut-off of synovial CC and PMN% following total knee (TKA) and total hip arthroplasty (THA). Methods. Between October 2012 and June 2017, all patients with painful TKA or THA, who underwent joint aspiration before revision arthroplasty were included in this retrospective study. From aspirated synovial fluid, leukocyte esterase activity, leukocyte CC and PMN% were determined, and specimens were sent for bacterial culture. A total of 524 preoperative joint aspirations (255 hips, 269 knees) were enrolled for final analysis. For 337 patients, the synovial CC and PMN% could be measured by the laboratory. From those patients, 203 patients were scheduled for aseptic revision, and 134 patients for septic revision arthroplasty according to the MSIS criteria for PJI. Specificity (SP), sensitivity (SE), positive predictive value (PPV), negative predictive and overall accuracy were measured for CC and PMN%. The optimum cut-off value was calculated by the ROC and the value giving the AUC, achieving the best possible level of sensitivity and specificity. Results. The best cut-off level for PJI of all study patients was 2582 leukocytes/μL (Se 80.6%, Sp 85.2%) and a PMN% of 66.1% (Se 80.6%, Sp 83.3%). The chosen cut-off levels for PJI of TKA was 1630 leukocytes/μL (Se 83.6%, Sp 82.2%) and a PMN% of 60.5% (Se 80.3%, Sp 77.1%). The optimal cut-off values for PJI of THA was 3063 leukocytes/μL (Se 78.1%, Sp 80.0%) and a PMN% of 66.1% (Se 82.2%, Sp 82.4%). Conclusions. Synovial cell count and polymorphonuclear percentage are sensitive methods for diagnosing PJI with differences in cut-off levels for THA and TKA. We suggest considering the cut-off levels of CC and PMN% from aspirates of TKA at 1600/μL and 60%, respectively, as possible PJI. For THA, the cut-off levels of CC and PMN% are at 3000/μL and 66%, respectively

Introduction. The demands placed upon joint surgeons are perhaps greatest when treating the revision arthroplasty patient, who present with complications demanding skill in diagnosis and evaluation, interpersonal communication and the technical aspects of the revision procedure. However, little information exists identifying which specific tasks in revision arthroplasty are most difficult for surgeons to master, and whether the greatest challenges arise from clinical, cognitive or technical facets of patient treatment. This study was undertaken to identify which tasks associated with revision total knee replacement (TKR) are perceived as most challenging to young surgeons and trainees to guide future efforts in surgical training and curriculum development. Methods. We developed an online survey instrument consisting of 69 items encompassing pre-operative, intraoperative, and post-operative tasks that preliminary studies identified as the essential components of revision TKR. These tasks encompassed 4 domains: clinical decision-making skills (n=9), interpersonal assessment and communication (n=7), surgical decision-making (n=35) and procedural surgical tasks (n=18). Respondents rated the difficulty of each item on a 5-level Likert scale, with an ordinal score ranging from 1 (“very easy”) to 5 (“very difficult”. The survey instrument was administered to a cohort of 109 US surgeons: 31 trainees enrolled in a joint fellowship program (Fellows) and 78 surgeons who had graduated from a joint fellowship program within the previous 10 years (Joint Surgeons). Using appropriate parametric and non-parametric tests, the responses were analyzed to examine the variation of reported difficulty of each of the 69 items, in addition to the nature of the task (cognitive, surgical, clinical and interpersonal), and differences between Fellows and Surgeons. Results. Both Fellows and Surgeons reported a wide variation in the difficulty of performing the tasks identified in each f the 4 domains. Fellows reported a higher average difficulty score than Surgeons (2.94 vs 2.74; p=0.032), corresponding to a greater frequency of tasks entailing some degree of difficulty (34.9% vs 24.4%, p<0.0001). Both groups experienced difficulty in performing tasks involving interpersonal interaction with patients (Fellows: 34.6% vs Surgeons: 34.3%, p=0.93). Fellows also found the technical aspects of revision surgery most challenging with 38.5% of items considered difficult compared to 28.7% for the Surgeon group (p<0.001). Highly significant differences between Fellows and Surgeons were also observed in facility with surgical decision making (p<0.001) and to a lesser extent, clinical decisions relating to patient care (% difficulty: p=0.0251). A compilation of the specific items cited as most difficult by the participants appears in Table 2. Conclusions. The young surgeons surveyed in this study reported difficulty in performing some tasks within both the clinical, cognitive and technical domains of revision knee arthroplasty. The high incidence of difficulty in tasks involving clinical decision-making and operative performance are characterized by a lack of accepted guidelines and the lack of a standard surgical practice. In general, our findings highlight the need for improvements in surgeon training to improve decision-making and procedural skills as part of the comprehensive management of patients undergoing revision knee arthroplasty. For any figures or tables, please contact authors directly

Aims

This study aims to determine difference in annual rate of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis, and to identify risk factors that may be associated with infection.