Aims. Rates of readmission and reoperation following primary total knee arthroplasty (TKA) are under scrutiny due to new payment models, which penalize these negative outcomes. Some risk factors are more modifiable than others, and some conditions considered modifiable such as obesity may not be as modifiable in the setting of advanced arthritis as many propose. We sought to determine whether controlling for hypoalbuminaemia would mitigate the effect that prior authors had identified in patients with obesity. Methods. We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for the period of January 2008 to December 2016 to evaluate the rates of reoperation and readmission within 30 days following primary TKA. Multivariate logistic regression modelling controlled for preoperative albumin, age, sex, and comorbidity status. Results. Readmission rates only differed significantly between patients with Normal Weight and Obesity Class II, with a decreased rate of readmission in this group (odds ratio (OR) 0.82; 95% confidence interval (CI) 0.71 to 0.96; p = 0.010). The only group demonstrating association with increased risk of reoperation within 30 days was the Obesity Class III group (OR 1.38; 95% CI 1.05 to 1.82; p = 0.022). Hypoalbuminaemia (preoperative albumin < 35 g/L) was significantly associated with readmission (OR 1.62; 95% CI 1.41 to 1.86; p < 0.001) and reoperation (OR 1.52; 95% CI 1.18 to 1.96; p = 0.001) within 30 days. Conclusion. In this study, hypoalbuminaemia appears to be a more significant risk factor for readmission and reoperation than even the highest obesity categories. Future studies may assess whether preoperative albumin restoration or weight loss may improve outcomes for patients with hypoalbuminaemia. The implications of this study may allow surgeons to discuss risk of surgery with obese patients planning to undergo primary TKA procedures if other comorbidities are adequately controlled. Cite this article: Bone Joint J 2020;102-B(6 Supple A):31–35

Aims. In the last decade, perioperative advancements have expanded the use of outpatient primary total knee arthroplasty (TKA). Despite this, there remains limited data on expedited discharge after revision TKA. This study compared 30-day readmissions and reoperations in patients undergoing revision TKA with a hospital stay greater or less than 24 hours. The authors hypothesized that expedited discharge in select patients would not be associated with increased 30-day readmissions and reoperations. Methods. Aseptic revision TKAs in the National Surgical Quality Improvement Program database were reviewed from 2013 to 2020. TKAs were stratified by length of hospital stay (greater or less than 24 hours). Patient demographic details, medical comorbidities, American Society of Anesthesiologists (ASA) grade, operating time, components revised, 30-day readmissions, and reoperations were compared. Multivariate analysis evaluated predictors of discharge prior to 24 hours, 30-day readmission, and reoperation. Results. Of 21,610 aseptic revision TKAs evaluated, 530 were discharged within 24 hours. Short-stay patients were younger (63.1 years (49 to 78) vs 65.1 years (18 to 94)), with lower BMI (32.3 kg/m. 2. (17 to 47) vs 33.6 kg/m. 2. (19 to 54) and lower ASA grades. Diabetes, chronic obstructive pulmonary disease, hypertension, and cancer were all associated with a hospital stay over 24 hours. Single component revisions (56.8% (n = 301) vs 32.4% (n = 6,823)), and shorter mean operating time (89.7 minutes (25 to 275) vs 130.2 minutes (30 to 517)) were associated with accelerated discharge. Accelerated discharge was not associated with 30-day readmission and reoperation. Conclusion. Accelerated discharge after revision TKA did not increase short-term complications, readmissions, or reoperations. Further efforts to decrease hospital stays in this setting should be evaluated. Cite this article: Bone Joint J 2022;104-B(12):1323–1328

Aims. The rate of day-case total knee arthroplasty (TKA) in the UK is currently approximately 0.5%. Reducing length of stay allows orthopaedic providers to improve efficiency, increase operative throughput, and tackle the rising demand for joint arthroplasty surgery and the COVID-19-related backlog. Here, we report safe delivery of day-case TKA in an NHS trust via inpatient wards with no additional resources. Methods. Day-case TKAs, defined as patients discharged on the same calendar day as surgery, were retrospectively reviewed with a minimum follow-up of six months. Analysis of hospital and primary care records was performed to determine readmission and reattendance rates. Telephone interviews were conducted to determine patient satisfaction. Results. Since 2016, 301/7350 TKAs (4.1%) in 290 patients at our institution were discharged on the day of surgery. Mean follow-up was 31.4 months (6.2 to 70.0). In all, 28 patients (9.3%) attended the emergency department or other acute care settings within 90 days of surgery, most often with wound concerns or leg swelling; six patients (2.0%) were readmitted. No patients underwent a subsequent revision procedure, and there were no periprosthetic infections. Two patients (0.7%) underwent secondary patella resurfacing, and one patient underwent arthroscopic arthrolysis after previous manipulation under anaesthetic (MUA). Three patients (1.0%) underwent MUA alone. Primary care consultation records, available for 206 patients, showed 16 patients (7.8%) contacted their general practitioner within two weeks postoperatively; two (1.0%) were referred to secondary care. Overall, 115/121 patients (95%) telephoned stated they would have day-case TKA again. Conclusion. Day-case TKA can be safely delivered in the NHS with no additional resources. We found low incidence of contact with primary and secondary care in the postoperative period, and high patient satisfaction. Cite this article: Bone Jt Open 2023;4(8):621–627

Introduction. Patients undergoing TJA have higher rates of anxiety and/or depression than the general population and higher costs of care. These preoperative diagnoses lead to higher levels of postoperative dissatisfaction and depression patients alone have higher readmission rates. There is significant crossover between anxiety and depressive disorders, and many patients are classed as combined. Our goal was to evaluate readmission rates of patients undergoing total hip or knee arthroplasty with diagnoses of anxiety, depression or both. Methods. Our hospital's prospectively collected data from our statewide total joint database (MARCQI) was reviewed from 2013–2018. Rates of anxiety and/or depression were determined based preoperative anxiolytic or antidepressant medications using national drug codes. Independent sample t-tests compared continuous variables and Chi-square tests (or Fisher's exact tests) compared categorical variables. Potential risk factors were identified by multivariable logistic regression modeling. Results. 4,107 cases (1,261 THA and 2,846 TKA) were included. 176 patients (4.28%) had a readmission within the 90-day global period. 476 patients (12%) had history of depression or anxiety or both. For the entire cohort, those on anxiolytic medication were 153% more likely to be readmitted than those not on medication (p=0.017). When patients were stratified based on THA or TKA, patients taking anxiolytic medication undergoing TKA were 120% more likely to undergo readmission within 90 days (p=0.021). Patients on depression medication alone were not at increased risk of readmission in the TKA cohort (p=0.991). For THA patients neither diagnosis appeared a risk factor for readmission (p=0.852). Conclusions. Patients with depression, anxiety, or both undergoing TKA were at a statistically significant risk of readmission within 90-days compared to patients without these diagnoses. Anxiety and depression were both risk factors for readmission, but anxiety appeared to have a more significant impact. THA on the other hand did not appear to share this risk profile

Introduction. Rates of readmission and reoperation following primary total knee arthroplasty (TKA) are under scrutiny due to new payment models, which penalize these negative outcomes. Many prior studies have demonstrated the risk of perioperative complications among patients with obesity. However, an elevated complication rate among patients with poor nutrition, as measured by hypoalbuminemia, has also been reported. We sought to determine whether controlling for hypoalbuminemia would mitigate the effect that prior authors had identified in patients with obesity. In addition, we hoped to identify an albumin threshold above which risk of readmission and reoperation would be minimized. Materials and Methods. We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for the period of 2008–2016 to evaluate the rates of perioperative complications among primary TKA patients by obesity category and albumin level. Patients were divided into groups according to World Health Organization obesity category and continuous as well as dichotomous albumin level. The primary outcomes were readmission and reoperation within 30 days of surgery. Patients without BMI or albumin data were excluded, as were patients undergoing surgery for the treatment of fracture or bone tumor. Univariate logistic regression compared predictive value of body mass index and albumin on incidence of these outcomes, using the normal weight and albumin > 3.5 g/dL groups as controls. Multivariate logistic regression modeling controlled for age, gender, and comorbidity status. Receiver operator curves (ROC) were generated to determine if an albumin threshold could be determined, above which risk for these complications would be minimized. Results. Outcome data was available 108,601 patients. Overall, 3,508 patients (3.46%) were readmitted and 1,219 patients (1.19%) underwent reoperation within 30 days. Hypoalbuminemia was present in 4,327 patients (4.11%), lowest in the Overweight group (3.16%) and highest in the Obese Type III (6.72%) and Underweight (12.62%) groups (p <0.001). Readmission and reoperation rates were highest among patients categorized as Obesity Class III (4.15 and 1.73%, respectively) compared with Normal Weight (3.59 and 1.14%, respectively, p <0.001). Readmission and reoperation rates were higher among patients with hypoalbuminemia (6.10 and 1.96%, respectively) compared with normal albumin (3.34 and 1.16%, respectively, p <0.001). After controlling for covariates of interest using multivariate regression including continuous albumin, odds ratio of readmission among the highest obesity category no longer differed from the Normal Weight control group. Odds ratio of reoperation among the highest obesity category declined from 1.52 to 1.38 after controlling for albumin and other covariates (p = 0.022). A subanalysis was performed excluding all patients with albumin < 3.5 g/dL, but results did not differ significantly from the multivariate model. ROC modeling was unable to identify a threshold for continuous BMI or albumin that would adequately mitigate risk for readmission or reoperation. Discussion. Albumin and obesity remain significant independent risk factors for reoperation following primary TKA procedures. However, after controlling for hypoalbuminemia and other important covariates, readmission rates did not significantly differ between patients with Normal Weight and any other obesity category. Controlling for albumin alone does not mitigate all risk imposed by obesity on perioperative outcomes. Future studies may assess whether preoperative albumin repletion or weight loss may improve outcomes for patients with hypoalbuminemia and obesity. For figures, tables, or references, please contact authors directly

Aims. Spinal anaesthesia has seen increased use in contemporary primary total knee arthroplasties (TKAs). However, controversy exists about the benefits of spinal in comparison to general anaesthesia in primary TKAs. This study aimed to investigate the pain control, length of stay (LOS), and complications associated with spinal versus general anaesthesia in primary TKAs from a single, high-volume academic centre. Methods. We retrospectively identified 17,690 primary TKAs (13,297 patients) from 2001 to 2016 using our institutional total joint registry, where 52% had general anaesthesia and 48% had spinal anaesthesia. Baseline characteristics were similar between cohorts with a mean age of 68 years (SD 10), 58% female (n = 7,669), and mean BMI of 32 kg/m. 2. (SD 7). Pain was evaluated using oral morphine equivalents (OMEs) and numerical pain rating scale (NPRS) data. Complications including 30- and 90-day readmissions were studied. Data were analyzed using an inverse probability of treatment weighted model based on propensity score that included many patient and surgical factors. Mean follow-up was seven years (2 to 18). Results. Patients treated with spinal anaesthesia required fewer postoperative OMEs (p < 0.001) and had lower NPRS scores (p < 0.001). Spinal anaesthesia also had fewer cases of altered mental status (AMS; odds ratio (OR) 1.3; p = 0.044), as well as 30-day (OR 1.4; p < 0.001) and 90-day readmissions (OR 1.5; p < 0.001). General anaesthesia was associated with increased risk of any revision (OR 1.2; p = 0.021) and any reoperation (1.3; p < 0.001). Conclusion. In the largest single institutional report to date, we found that spinal anaesthesia was associated with significantly lower OME use, lower risk of AMS, and lower overall 30- and 90-day readmissions following primary TKAs. Additionally, spinal anaesthesia was associated with reduced risk of any revision and any reoperation after accounting for numerous patient and operative factors. When possible and safe, spinal anaesthesia should be considered in primary TKAs. Cite this article: Bone Joint J 2022;104-B(11):1209–1214

Abstract. Introduction. The rate of day-case total knee replacement (TKR) in the UK is currently ~0.5%. Reducing length of stay improves efficiency, increases operative throughput and tackles the rising demand for joint replacement surgery and the COVID-19 related backlog. We report safe delivery of day-case TKR in an NHS Trust via inpatient wards, with no additional resources. Methodology. Day-case TKRs, defined as patients discharged on the same calendar day as surgery, were retrospectively reviewed with a minimum follow-up of six-months. Analysis of hospital and primary care records was performed to determine readmission and reattendance rates. Telephone interviews were conducted to determine patient satisfaction. Results. Between 2016 and 2021, 301/7350 (4.1%) TKRs were discharged on the day of surgery. Mean follow-up was 31.4 (6.2–70.0) months. 28 (9.3%) patients attended Accident and Emergency or other acute care settings within 90-days of surgery; six (2.0%) patients were readmitted. No patients underwent a subsequent revision procedure. There were no prosthetic infections. Two patients underwent secondary patella resurfacing, and one patient underwent arthroscopic arthrolysis after previous manipulation under anaesthetic (MUA). Three patients underwent MUA alone. Primary care consultation records, available for 206 patients, showed 16 (7.8%) patients contacted their General Practitioner within two-weeks post-operatively; two (1.0%) were referred to secondary care. 115/121 (95%) patients telephoned stated they would have day-case TKR again. Conclusion. Day-case TKR can be safely delivered in the NHS with no additional resources. We found low incidence of contact with primary and secondary care in the post-operative period, and high patient satisfaction

Haematomas, drainage, and other non-infectious wound complications following total knee replacement (TKR) have been associated with long-term sequelae, in particular, deep infection. However, the impact of these wound complications on clinical outcome is unknown. This study compares results in 15 patients re-admitted for wound complications within 90 days of TKR to 30 matched patients who underwent uncomplicated total knee replacements. Patients with wound complications had a mean age of 66 years (49 to 83) and mean body mass index (BMI) of 37 (21 to 54), both similar to that of patients without complications (mean age 65 years and mean BMI 35). Those with complications had lower mean Knee Society function scores (46 (0 to 100 vs 66 (20 to 100), p = 0.047) and a higher incidence of mild or greater pain (73% vs 33%, p = 0.01) after two years compared with the non re-admitted group. Expectations in patients with wound complications following TKR should be tempered, even in those who do not develop an infection.

Cite this article: Bone Joint J 2014;96-B:619–21.

Abstract. Introduction. 30-day emergency readmission is an indicator of treatment related complication once discharged, resulting in readmission. A board-approved quality improvement pathway was introduced to reduce elective re-admissions. Method. The pathway involved telephone and email contact details provision to patients for any non-life threatening medical assistance, allowing for initial nurse led management of all issues. A new clinic room available 7 days, and same day ultrasound scanning for DVT studies were introduced. A capability, opportunity and behavior model of change was implemented. Readmission rates before and six months after implementation were collected from Model Hospital. A database used to document patient communications was interrogated for patient outcomes. Results. Prior to implementation, readmission rates following elective primary total knee replacement (TKR) at the 1st business quarter of 2021 (April – June 2021), was 8.7%, (benchmark 3.8%). Following implementation, readmission rates decreased to 4.1% (October – December 2021). 54% of patients making contact were managed with telephone advice. 15% of patients required face-to-face clinic. 32% of those required a same day scan to exclude DVT (1/4). 20 out of 684 TKRs performed following protocol introduction were re-admitted within 30 days. Readmissions were 41% surgical, 29% medical. 52% were unaware of the newly implemented protocol. Further improvements have been made to the protocol based on these findings. Implementation of a suitable pathway can significantly reduce re-admission rates in our center and could be used to reduce readmission rates in other national elective treatment centers

Aims. Medial unicompartmental knee arthroplasty (mUKA) is an advised treatment for anteromedial knee osteoarthritis. While long-term survival after mUKA is well described, reported incidences of short-term surgical complications vary and the effect of surgical usage on complications is less established. We aimed to describe the overall occurrence and treatment of surgical complications within 90 days of mUKA, as well as occurrence in high-usage centres compared to low-usage centres. Methods. mUKAs performed in eight fast-track centres from February 2010 to June 2018 were included from the Lundbeck Foundation Centre for Fast-track Hip and Knee Replacement Database. All readmissions within 90 days of surgery underwent chart review and readmissions related to the surgical wound or the prosthesis were recorded. Centres were categorized as high-usage centres when using mUKA in ≥ 20% of annual knee arthroplasties. The occurrence of complications between high- and low-usage centres were compared using Fisher’s exact test. Results. We included 3,757 mUKAs: 2,377 mUKAs from high-usage centres and 1,380 mUKAs from low-usage centres. Surgical complications within 90 days occurred in 69 cases (1.8%), 45 (1.9%) in high-usage centres and 24 (1.7%) in low-usage centres (odds ratio (OR) 1.1 (95% confidence interval (CI) 0.65 to 1.8)). The most frequent complications were periprosthetic joint infections (PJIs) (n = 18; 0.48%), wound-related issues (n = 14; 0.37%), and periprosthetic fractures (n = 13; 0.35%). Bearing dislocations (n = 7; 0.19%) occurred primarily in procedures from high-usage centres. In high-usage centres, seven periprosthetic fractures (0.29%) occurred compared to six (0.43%) in low-usage centres (OR 0.68 (95% CI 0.20 to 2.0)). In high-usage centres, nine PJIs (0.38%) occurred compared to nine (0.65%) in low-usage centres (OR 0.58 (95% CI 0.22 to 1.6)). Conclusion. Surgical complications are rare after fast-track mUKA surgery and with no difference in overall occurrence of surgical complications between high- and low-usage centres, although the risk of some specific surgical complications may favour high-usage centres. Cite this article: Bone Jt Open 2023;4(6):457–462

Aims. The purpose of this study was to assess total knee arthroplasty (TKA) volume and rates of early complications in morbidly obese patients over the last decade, where the introduction of quality models influencing perioperative care pathways occurred. Methods. Patients undergoing TKA between 2011 to 2018 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by BMI < 40 kg/m. 2. and ≥ 40 kg/m. 2. and evaluated by the number of cases per year. The 30-day rates of any complication, wound complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between groups using odds ratios (ORs) and multivariate analyses. Results. In total, 314,695 patients underwent TKA and 46,362 (15%) had BMI ≥ 40 kg/m. 2. The prevalence of morbid obesity among TKA patients did not change greatly, ranging between 14% and 16%. Reoperation rate decreased from 1.16% to 0.96% (odds ratio (OR) 0.81 (95% confidence interval (CI) 0.66 to 0.99)) for patients with BMI < 40 kg/m. 2. , as did rates of readmission (4.46% to 2.87%; OR 0.61 (0.55 to 0.69)). Patients with BMI ≥ 40 kg/m. 2. also had fewer readmissions over the study period (4.87% to 3.34%; OR 0.64 (0.49 to 0.83)); however, the rate of reoperation did not change (1.37% to 1.41%; OR 0.99 (0.62 to 1.56)). Significant improvements were not observed for infective complications over time for either group; patients with BMI ≥ 40 kg/m. 2. had increased risk of both deep infection and wound complications compared to non-morbidly obese patients. Rate of any complication decreased for all patients. Conclusion. The proportion of TKAs in morbidly obese patients has not significantly changed over the past decade. Although readmission rates improved for all patients, reductions in reoperation in non-morbidly obese patients were not experienced by the morbidly obese, resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infective complications in the morbidly obese. Cite this article: Bone Joint J 2021;103-B(6 Supple A):38–44

Aims. The purpose of this study was to develop a personalized outcome prediction tool, to be used with knee arthroplasty patients, that predicts outcomes (lengths of stay (LOS), 90 day readmission, and one-year patient-reported outcome measures (PROMs) on an individual basis and allows for dynamic modifiable risk factors. Methods. Data were prospectively collected on all patients who underwent total or unicompartmental knee arthroplasty at a between July 2015 and June 2018. Cohort 1 (n = 5,958) was utilized to develop models for LOS and 90 day readmission. Cohort 2 (n = 2,391, surgery date 2015 to 2017) was utilized to develop models for one-year improvements in Knee Injury and Osteoarthritis Outcome Score (KOOS) pain score, KOOS function score, and KOOS quality of life (QOL) score. Model accuracies within the imputed data set were assessed through cross-validation with root mean square errors (RMSEs) and mean absolute errors (MAEs) for the LOS and PROMs models, and the index of prediction accuracy (IPA), and area under the curve (AUC) for the readmission models. Model accuracies in new patient data sets were assessed with AUC. Results. Within the imputed datasets, the LOS (RMSE 1.161) and PROMs models (RMSE 15.775, 11.056, 21.680 for KOOS pain, function, and QOL, respectively) demonstrated good accuracy. For all models, the accuracy of predicting outcomes in a new set of patients were consistent with the cross-validation accuracy overall. Upon validation with a new patient dataset, the LOS and readmission models demonstrated high accuracy (71.5% and 65.0%, respectively). Similarly, the one-year PROMs improvement models demonstrated high accuracy in predicting ten-point improvements in KOOS pain (72.1%), function (72.9%), and QOL (70.8%) scores. Conclusion. The data-driven models developed in this study offer scalable predictive tools that can accurately estimate the likelihood of improved pain, function, and quality of life one year after knee arthroplasty as well as LOS and 90 day readmission. Cite this article: Bone Joint J 2020;102-B(9):1183–1193

Aims. The aim of this prospective multicentre study was to describe trends in length of stay and early complications and readmissions following unicompartmental knee arthroplasty (UKA) performed at eight different centres in Denmark using a fast-track protocol and to compare the length of stay between centres with high and low utilization of UKA. Methods. We included data from eight dedicated fast-track centres, all reporting UKAs to the same database, between 2010 and 2018. Complete ( > 99%) data on length of stay, 90-day readmission, and mortality were obtained during the study period. Specific reasons for a length of stay of > two days, length of stay > four days, and 30- and 90-day readmission were recorded. The use of UKA in the different centres was dichotomized into ≥ 20% versus < 20% of arthroplasties which were undertaken being UKAs, and ≥ 52 UKAs versus < 52 UKAs being undertaken annually. Results. A total of 3,927 procedures were included. Length of stay (mean 1.1 days (SD 1.1), median 1 (IQR 0 to 1)) was unchanged during the study period. The proportion of procedures with a length of stay > two days was also largely unchanged during this time. The percentage of patients discharged on the day of surgery varied greatly between centres (0% to 50% (0 to 481)), with centres with high UKA utilization (both usage and volume) having a larger proportion of same-day discharges. The 30- and 90-day readmissions were 166 (4.2%) and 272 (6.9%), respectively; the 90-day mortality was 0.08% (n = 3). Conclusion. Our findings suggest general underutilization of the potential for quicker recovery following UKA in a fast-track setup. Cite this article: Bone Joint J 2020;102-B(9):1167–1175

Aims. To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration. Methods. We performed a systematic literature search in MEDLINE, Embase, and Web of Science. The search string included multiple synonyms of the following keywords: "revision TKA", "outcome" and "prognostic factor". We searched for studies assessing the association between at least one prognostic factor and at least one outcome measure after rTKA surgery. Data on sample size, study design, prognostic factors, outcomes, and the direction of the association was extracted and included in an evidence map. Results. After screening of 5,660 articles, we included 166 studies reporting prognostic factors for outcomes after rTKA, with a median sample size of 319 patients (30 to 303,867). Overall, 50% of the studies reported prospectively collected data, and 61% of the studies were performed in a single centre. In some studies, multiple associations were reported; 180 different prognostic factors were reported in these studies. The three most frequently studied prognostic factors were reason for revision (213 times), sex (125 times), and BMI (117 times). Studies focusing on functional scores and patient-reported outcome measures as prognostic factor for the outcome after surgery were limited (n = 42). The studies reported 154 different outcomes. The most commonly reported outcomes after rTKA were: re-revision (155 times), readmission (88 times), and reinfection (85 times). Only five studies included costs as outcome. Conclusion. Outcomes and prognostic factors that are routinely registered as part of clinical practice (e.g. BMI, sex, complications) or in (inter)national registries are studied frequently. Studies on prognostic factors, such as functional and sociodemographic status, and outcomes as healthcare costs, cognitive and mental function, and psychosocial impact are scarce, while they have been shown to be important for patients with osteoarthritis. Cite this article: Bone Jt Open 2023;4(5):338–356

Abstract. Introduction. Surgery in patients with high body mass index (BMI) is more technically challenging and associated with increased complications post-operatively. Inferior clinical and functional mid-term results for high BMI patients undergoing high tibial osteotomy (HTO) relative to normal weight patients have been reported. This study discusses the clinical, radiological and functional outcomes of HTO surgery in patients with a high BMI. Method. This is a retrospective study on patients undergoing HTO surgery using the Tomofix anatomical MHT plate between 2017 and 2022, with follow-up period of up to 5 years. The cohort was divided: non-obese (BMI <30 kg/m2) and obese (BMI>30 kg/m2). Pre and post operative functional scores were collected: Oxford Knee Score (OKS), EuroQol-5D and Tegner. Complications, plate survivorship and Mikulicz point recorded. Results. 32 HTO procedures; 19 patients BMI <30 (average 27.0) and 14 patients BMI >30 (average 36.1). In BMI<30 cohort, one readmission for investigation of venous thromboembolism, doppler negative; two complications: hinge fracture and stitch abscess. The five year survivorship of the plate was 100%. In BMI>30 cohort, one readmission for pulmonary embolism; one complication: hinge fracture. The 5 year survivorship of the plate was 93%, 1 conversion to unicompartmental knee replacement. The average OKS improvement was 17 and 18 for BMI <30 and >30 respectively. Mikulicz point change was identical. Conclusion. The Tomofix anatomical MHT plate achieves good outcomes and minimal complications irrespective of BMI. Reduced plate survivorship, thus earlier conversion may be required in the obese, however higher cohort numbers are needed to confirm this

Abstract. Introduction. Uni-compartmental knee replacement (UKR) has become popularised due to quicker recovery times, reduced postoperative pain, and blood loss. The desire to increase bed capacity and reduce costs, while preserving safety and patient satisfaction, has led to increased interest in day-case arthroplasty. This study observes the feasibility of UKR as a day-case procedure and whether this affects short and long-term postoperative outcomes. Methodology. Between 2018 and 2021, at a single institution and operated by a single orthopaedic surgeon, seventy-seven patients received a UKR on an elective basis. The patients were divided into two groups: ‘day-case’ for those discharged on the same day, and ‘non day-case’ group. Results. 31 patients were identified as day case procedures with the remaining 46 requiring between one to three days before discharge. Mean age, sex, modal ASA score, BMI, Charlson co-morbidity index, and pre-op oxford knee score showed no statistically significant difference between the two groups (p>0.05). No significant difference between the post-op oxford knee score at 1 year was found for patients treated and discharged as a day case procedure (37.8 +/− 6.88) and those who remained as an inpatient postoperatively (37.8 +/− 10.7); t(df) = −0.0007, p=0.994. No patients in either group suffered any complications beyond the peri-operative period. 30-day and 90-day readmission rates were equal. Conclusions. With no significant differences in post-op knee scores, complication, and readmission rates, we feel UKR can be performed as a viable day case procedure in a planned elective setting. This will result in significant cost savings

Aims. In-hospital length of stay (LOS) and discharge dispositions following arthroplasty could act as surrogate measures for improvement in patient pathways, and have major cost saving implications for healthcare providers. With the ever-growing adoption of robotic technology in arthroplasty, it is imperative to evaluate its impact on LOS. The objectives of this study were to compare LOS and discharge dispositions following robotic arm-assisted total knee arthroplasty (RO TKA) and unicompartmental arthroplasty (RO UKA) versus conventional technique (CO TKA and UKA). Methods. This large-scale, single-institution study included patients of any age undergoing primary TKA (n = 1,375) or UKA (n = 337) for any cause between May 2019 and January 2023. Data extracted included patient demographics, LOS, need for post anaesthesia care unit (PACU) admission, anaesthesia type, readmission within 30 days, and discharge dispositions. Univariate and multivariate logistic regression models were also employed to identify factors and patient characteristics related to delayed discharge. Results. The median LOS in the RO TKA group was 76 hours (interquartile range (IQR) 54 to 104) versus 82.5 (IQR 58 to 127) in the CO TKA group (p < 0.001) and 54 hours (IQR 34 to 77) in the RO UKA versus 58 (IQR 35 to 81) in the CO UKA (p = 0.031). Discharge dispositions were comparable between the two groups. A higher percentage of patients undergoing CO TKA required PACU admission (8% vs 5.2%; p = 0.040). Conclusion. Our study showed that robotic arm assistance was associated with a shorter LOS in patients undergoing primary UKA and TKA, and no difference in the discharge destinations. Our results suggest that robotic arm assistance could be advantageous in partly addressing the upsurge of knee arthroplasty procedures and the concomitant healthcare burden; however, this needs to be corroborated by long-term cost-effectiveness analyses and data from randomized controlled studies. Cite this article: Bone Jt Open 2023;4(10):791–800

Aims. It has been shown that the preoperative modification of risk factors associated with obesity may reduce complications after total knee arthroplasty (TKA). However, the optimal method of doing so remains unclear. The aim of this study was to investigate whether a preoperative Risk Stratification Tool (RST) devised in our institution could reduce unexpected intensive care unit (ICU) transfers and 90-day emergency department (ED) visits, readmissions, and reoperations after TKA in obese patients. Methods. We retrospectively reviewed 1,614 consecutive patients undergoing primary unilateral TKA. Their mean age was 65.1 years (17.9 to 87.7) and the mean BMI was 34.2 kg/m. 2. (SD 7.7). All patients underwent perioperative optimization and monitoring using the RST, which is a validated calculation tool that provides a recommendation for postoperative ICU care or increased nursing support. Patients were divided into three groups: non-obese (BMI < 30 kg/m. 2. , n = 512); obese (BMI 30 kg/m. 2. to 39.9 kg/m. 2. , n = 748); and morbidly obese (BMI > 40 kg/m. 2. , n = 354). Logistic regression analysis was used to evaluate the outcomes among the groups adjusted for age, sex, smoking, and diabetes. Results. Obese patients had a significantly increased rate of discharge to a rehabilitation facility compared with non-obese patients (38.7% (426/1,102) vs 26.0% (133/512), respectively; p < 0.001). When stratified by BMI, discharge to a rehabilitation facility remained significantly higher compared with non-obese (26.0% (133)) in both obese (34.2% (256), odds ratio (OR) 1.6) and morbidly obese (48.0% (170), OR 3.1) patients (p < 0.001). However, there was no significant difference in unexpected ICU transfer (0.4% (two) non-obese vs 0.9% (seven) obese (OR 2.5) vs 1.7% (six) morbidly obese (OR 5.4); p = 0.054), visits to the ED (8.6% (44) vs 10.3% (77) (OR 1.3) vs 10.5% (37) (OR 1.2); p = 0.379), readmissions (4.5% (23) vs 4.0% (30) (OR 1.0) vs 5.1% (18) (OR 1.4); p = 0.322), or reoperations (2.5% (13) vs 3.3% (25) (OR 1.2) vs 3.1% (11) (OR 0.9); p = 0.939). Conclusion. With the use of a preoperative RST, morbidly obese patients had similar rates of short-term postoperative adverse outcomes after primary TKA as non-obese patients. This supports the assertion that morbidly obese patients can safely undergo TKA with appropriate perioperative optimization and monitoring. Cite this article: Bone Joint J 2021;103-B(6 Supple A):45–50

Abstract. Introduction. COMPOSE describes the demographics, fracture characteristics, management and associated outcomes of knee femoral periprosthetic fractures (KFPPF). Methods. Multicentre retrospective cohort study conducted 01/01/2018-31/12/2018. Data collected included: patient demographics, social and mobility characteristics, fracture characteristics, management strategy and post-treatment outcomes (length of stay, reoperation, readmission, 30-day and 12-month mortality). Results. 785 PPFs from 27 NHS sites were included in the COMPOSE cohort. Of these 162 (21%) were related to an isolated knee prosthesis (151 femur, 10 tibia and 1 patella). The KFPPF group had a mean age of 81.1 years, 127 (84%) female, 114 (76%) living in their own home, with 99 (63%) reliant on walking aids/bedbound. Most fractures were B (58%) or C (35%) type and occurred around a primary cemented replacement (141,94%) at a mean of 8.2 years after surgery. 116 (76.8%) KFPPFs were treated operatively. Mean time to surgery was 5 days and the commonest surgical strategy was fixation alone (64%) vs revision+/-fixation (36%). Mean operative time was 126 minutes and 11 (10%) patients required ITU/HDU admission after surgery. Mean LOS was 22 days and 47 patients (31%) experienced a complication prior to discharge. Overall, 5 patients (3%) had a further operation within 12 months, 7 (5%) were readmitted within 30 days and the 30-day and 12-month mortality were 6.6% and 23.2% respectively. Conclusions. KFPPF patients are elderly and frail and have mortality, re-operation and readmission rates comparable to hip fracture patients. However, they wait longer for surgery and surgical treatment is more complex

Introduction. Perioperative optimization efforts have improved outcomes following primary total knee arthroplasty (TKA). However, morbidly obese patients continue to have increased rates of complications. The purpose of this study was to assess if rates of early complications after TKA have similarly improved for both morbidly obese and non-morbidly obese patients. Methods. Elective, primary TKA patients from 2011–2018 were identified in the National Surgical Quality Improvement Program database. Patients were stratified by body mass index (BMI) <40 kg/m. 2. and ≥40 kg/m. 2. Thirty-day rates of infectious complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between BMI groups utilizing odds ratios (OR) and multivariate analyses. Results. In total, 314,719 patients underwent TKA and 46,386 (15%) had BMI ≥40 kg/m. 2. From 2011–2018, the reoperation rate significantly improved from 1.2% to 1.0% (OR: 0.6 [0.6–0.7]) for patients with BMI <40 kg/m. 2. , as did rates of readmission (4.5% to 2.9%, OR: 0.8 [0.7–0.99]). Patients with BMI ≥40 kg/m. 2. also had a significant decrease in the rate of readmission over the study period (4.9% to 3.3%, OR: 0.6 [0.5–0.8]); however, the rate of reoperation did not significantly change (1.4% to 1.4%, OR: 1.0 [0.6–1.6]). Significant improvements were not observed for infectious complications over time for either group. However, patients with BMI ≥40 kg/m. 2. consistently had increased risk of both deep infection from 2014–2018 (2014 OR: 2.2 [1.4–3.4], 2018: 2.2 [1.6–3.0]) and wound complications from 2011–2018 (2011 OR: 1.7 [1.2–2.6], 2018 OR: 2.0 [1.7–2.4]) compared to non-morbidly obese patients. Conclusion. Although readmission rates significantly decreased for all patients, improvements in reoperation rates observed in non-morbidly obese patients were not experienced by the morbidly obese – resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infectious complications compared to non-morbidly obese