Implementation of outpatient hip and knee arthroplasty in a multicenter public healthcare setting.

BACKGROUND AND PURPOSE: Length of hospital stay after hip and knee arthroplasty is about 1 day in Denmark with few patients discharged on the day of surgery. Hence, a protocol for multicenter implementation of discharge on day of surgery has been instituted. We aimed to describe the implementation of outpatient hip and knee arthroplasty in a multicenter public healthcare setting. METHODS: We performed a prospective multicenter study from 7 public hospitals across Denmark. Patients were screened using well-defined in- and exclusion criteria and were discharged on day of surgery when fulfilling functional discharge criteria. The study period was from September 2022 to February 2023 with variable start of implementation. Data from the same centers in a 6-month period before the COVID pandemic from July 2019 to December 2019 was used for baseline control. RESULTS: Of 2,756 primary hip and knee arthroplasties, 37% (95% confidence interval [CI] 35-39) were eligible (range 21-50% in centers) and 52% (range 24-62%) of these were discharged on day of surgery. 21% (CI 20-23) of all patients (eligible and non-eligible) were discharged on day of surgery with a range of 10-31% within centers. This was an additional 15% (CI 13-17, P < 0.001) compared with patients discharged in the control period (6% in 2019). CONCLUSION: We found it possible to perform outpatient hip and knee replacement in 21% of patients in a public healthcare setting, probably to be increased with further center experience.

Postoperative orthostatic intolerance following fast-track unicompartmental knee arthroplasty: incidence and hemodynamics-a prospective observational cohort study.

BACKGROUND: Early postoperative mobilization is essential for early functional recovery but can be inhibited by postoperative orthostatic intolerance (OI). Postoperative OI is common after major surgery, such as total knee arthroplasty (TKA). However, limited data are available after less extensive surgery, such as unicompartmental knee arthroplasty (UKA). We, therefore, investigated the incidence of OI as well as cardiovascular and tissue oxygenation responses during early mobilization after UKA. METHODS: This prospective single-centre observational study included 32 patients undergoing primary UKA. Incidence of OI and cardiovascular and tissue oxygenation responses during mobilization were evaluated preoperatively, at 6 and 24 h after surgery. Perioperative fluid balance, bleeding, surgery duration, postoperative hemoglobin, pain during mobilization and opioid usage were recorded. RESULTS: During mobilization at 6 h after surgery, 4 (14%, 95%CI 4-33%) patients experienced OI; however, no patients terminated the mobilization procedure prematurely. Dizziness and feeling of heat were the most common symptoms. OI was associated with attenuated systolic and mean arterial blood pressure responses in the sitting position (all p < 0.05). At 24 h after surgery, 24 (75%) patients had already been discharged, including three of the four patients with early OI. Only five patients were available for measurements, two of whom experienced OI; one terminated the mobilization procedure due to intolerable symptoms. We observed no statistically significant differences in perioperative fluid balance, bleeding, surgery duration, postoperative hemoglobin, pain, or opioid usage between orthostatic intolerant and tolerant patients. CONCLUSIONS: The incidence of orthostatic intolerance after fast-track unicompartmental knee arthroplasty is low (~ 15%) and is associated with decreased orthostatic pressure responses. Compared to the previously described orthostatic intolerance incidence of ~ 40% following total knee arthroplasty, early orthostatic intolerance is uncommon after unicompartmental knee arthroplasty, suggesting a procedure-specific component. TRIAL REGISTRATION: Prospectively registered at ClinicalTrials.gov; registration number: NCT04195360, registration date: 13.12.2019.

Protocol for a prospective multicentre cohort study to address the question whether diabetes and its management is still a risk factor in fast-track joint arthroplasty.

INTRODUCTION: Perioperative glycaemic control is important. However, the complexity of guidelines for perioperative diabetes management is complicated due to different and novel antihyperglycaemic medications, limited procedure-specific data and lack of data from implemented fast-track regimens which otherwise are known to reduce morbidity and glucose homeostasis disturbances. Consequently, outcome in patients with diabetes mellitus (DM) after surgery and the influence of perioperative diabetes management on postoperative recovery remains poorly understood. METHODS AND ANALYSIS: A prospective observational multicentre study involving 8 arthroplasty centres across Denmark with a documented implemented fast-track programme (median length of hospitalisation (LOS) 1 day). We will collect detailed perioperative data including preoperative haemoglobin A1c and antidiabetic treatment in 1400 unselected consecutive patients with DM undergoing hip and knee arthroplasty from September 2022 to December 2025, enrolled after consent. Follow-up duration is 90 days after surgery. The primary outcome is the proportion of patients with DM with LOS >4 days and 90-day readmission rate after fast-track total hip arthroplasty (THA), total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA). The secondary outcome is the association between perioperative diabetes treatment and LOS >2 days, 90-day readmission rate, other patient demographics and Comprehensive Complication Index for patients with DM after THA/TKA/UKA in a fast-track regimen. ETHICS AND DISSEMINATION: The study will follow the principles of the Declaration of Helsinki and ICH-Good Clinical Practice guideline. Ethical approval was not necessary as this is a non-interventional observational study on current practice. The trial is registered in the Region of Southern Denmark and on ClinicalTrials.gov. The main results and all substudies of this trial will be published in peer-reviewed international medical journals. TRIAL REGISTRATION NUMBER: NCT05613439.

Champions in usage of medial unicompartmental knee arthroplasty : The story behind the Danish success.

Historically, the use of medial unicompartmental knee arthroplasty (mUKA) as treatment for end-stage anteromedial osteoarthritis (AMOA) of the knee was limited by contraindications due to age, weight, and activity level; however, now evidence-based, validated, and less selective criteria are used rendering nearly 50% of end-stage OA patients eligible for mUKA. Recent studies have showcased benefits, such as shorter hospital stays, cost efficiency, and comparable functional outcomes to total knee arthroplasty (TKA). Notably, revision rates have been shown to markedly decrease with increased usage, with an ideal usage of > 30% but an acceptable usage of 20-60%. The usage of unicompartmental knee arthroplasty (UKA) varies among countries, with Denmark achieving a notably higher usage compared to Sweden, the UK, the Netherlands, the USA and Germany. This article investigates potential factors contributing to Denmark having a higher national usage of mUKA, surpassing the recommended threshold of a usage > 20%. We explore the tradition for national alliances and streamlined surgical education as possible explanations of this development. These insights offer valuable perspectives for potentially optimizing surgical approaches and implant choices in the surgical treatment of end-stage AMOA of the knee across diverse healthcare settings, underscoring the impact of collective strategies in advancing knee arthroplasty practices, ultimately benefiting patients.

Patient attitudes towards day-case hip and knee arthroplasty.

Aims: This study aimed to investigate patients' attitudes towards day-case hip and knee arthroplasty and to describe patient characteristics associated with different attitudes, with the purpose of providing an insight into the information requirements for patients that surgeons should address when informing patients about day-case surgery. Methods: A total of 5,322 patients scheduled for hip or knee arthroplasty between 2016 and 2022 were included in the study. Preoperatively, patients were asked if they were interested in day-case surgery ('Yes', 'Do not know', 'No'). Patient demographics including age, BMI, sex, and patient-reported outcome measures (PROMs) such as the EuroQol five-dimension three-level questionnaire (EQ-5D-3L) were examined within each attitude group. Additionally, changes in attitude were assessed among patients who had completed the questionnaire in association with prior hip or knee arthroplasty. Results: Of the surveyed patients, 41.8% were interested in day-case surgery (n = 2,222), 20.8% responded 'Do not know' (n = 1,105), and 37.5% were not interested (n = 1,995). Patients who were not interested had a higher mean age ('No', 70.2 years (SD 10.0) vs 'Yes', 65.2 years (SD 10.7)), with a majority being female ('No', 71.9% female (n = 1,434) vs 'Yes', 48.6% female (n = 1,081)). Approximately 20% of patients responded 'Do not know' regardless of age, sex, and PROMs. Patients reporting anxiety/depression based on EQ-5D-3L more frequently answered 'No' (56.9%; 66/116) compared to those not experiencing anxiety/depression (34.9%; 1,356/3,890). Among patients who responded 'Do not know' before their first surgery, over 70% changed their attitude to either 'Yes' (29.9%; 38/127) or 'No' (40.9%; 52/127) at their subsequent surgery. Conclusion: From 2016 to 2022, 58.3% of hip and knee arthroplasty patients expressed uncertainty or no interest in day-case surgery. In connection with current initiatives to increase the number of day-case arthroplasty procedures, there should be a focus on informing patients to address the prevalent negative or uncertain attitude. Further research is needed to investigate what preoperative information patients consider crucial in their decision-making process regarding day-case surgery.

Half of all hip and knee arthroplasty patients may be potential day-case candidates: a nationwide register study of 166,730 procedures.

BACKGROUND AND PURPOSE: The overall potential pool of day-case candidates on a national level in hip and knee arthroplasty is unknown. We aimed to estimate the proportion of hip and knee arthroplasty patients eligible for day-case surgery based on contemporary widely used criteria and determine whether there has been a change in the proportion of eligible patients over time and, secondarily, to investigate the proportion of eligible patients discharged on the day of surgery. METHODS: Based on data from the Danish National Patient Register, we identified all patients undergoing primary unilateral hip or knee arthroplasty from January 2010 to March 2020. Using a modification of day-case eligibility criteria proposed by a national multicenter collaboration, we sorted patients into either day-case eligible or ineligible. A day-case procedure was defined as discharge on the day of surgery. RESULTS: We included patients comprising a total of 166,730 primary total hip (THA), total knee (TKA), and unicompartmental knee arthroplasty (UKA). 48% (95% confidence interval [CI] 48-49) were eligible for day-case surgery, with a decline from 50% (CI 49-51) in 2010 to 46% (CI 46-47) eligible in 2019. More UKA patients were day-case eligible (55%, CI 54-56) than THA (47%, CI 47-48) and TKA patients (49%, CI 48-49). A maximum of 8.0% (CI 7.4-8.5) of eligible patients were discharged on the day of surgery in 2019. CONCLUSION: 48% of the Danish hip and knee arthroplasty patients were potential day-case candidates, with a small decline in eligibility from 50% in 2010 to 46% in 2019. Day of surgery discharge among day-case eligible patients peaked at 8% in 2019. Thus, the potential for more day-case surgery seems large.

Spinal anaesthesia versus general anaesthesia (SAGA) on recovery after hip and knee arthroplasty: A study protocol for three randomized, single-blinded, multi-centre, clinical trials.

Mobilisation difficulties, due to muscle weakness, and urinary retention are common reasons for prolonged admission following hip and knee arthroplasty procedures. Whether spinal anaesthesia is detrimental to early mobilisation is controversial. Previous studies have reported differences in post-operative recovery between spinal anaesthesia and general anaesthesia; however, up-to-date comparisons in fast-track setups are needed. Our randomized, single-blinded, multi-centre, clinical trials aim to compare the post-operative recovery after total hip (THA), total knee (TKA), and unicompartmental knee arthroplasties (UKA) respectively when using either spinal anaesthesia (SA) or general anaesthesia (GA) in a fast-track setup. Included patients (74 THA, 74 TKA, and 74 UKA patients) are randomized (1:1) to receive either SA (2 mL 0.5% Bupivacaine) or GA (Induction: Propofol 1.0-2.0 mg/kg iv with Remifentanil 3-5 mcg/kg iv. Infusion: Propofol 3-5 mg/kg/h and Remifentanil 0.5 mcg/kg/min iv). Patients undergo standard primary unilateral hip and knee arthroplasty procedures in an optimized fast-track setup with intraoperative local infiltrative analgesia in TKA and UKA, post-operative multimodal opioid sparing analgesia, immediate mobilisation with full weightbearing, no drains and in-hospital only thromboprophylaxis. Data will be collected on the day of surgery and until patients are discharged. The primary outcome is the ability to be safely mobilised during a 5-m walking test within 6 h of surgery. Secondary outcomes include fulfilment of discharge criteria, post-operative pain, dizziness, and nausea as well as patient reported recovery and opioid related side effects. Data will also be gathered on all hospital contacts within 30-days of surgery. This study will offer insights into advantages and disadvantages of anaesthetic methods used in fast-track arthroplasty surgery.

Machine-learning vs. logistic regression for preoperative prediction of medical morbidity after fast-track hip and knee arthroplasty-a comparative study.

BACKGROUND: Machine-learning models may improve prediction of length of stay (LOS) and morbidity after surgery. However, few studies include fast-track programs, and most rely on administrative coding with limited follow-up and information on perioperative care. This study investigates potential benefits of a machine-learning model for prediction of postoperative morbidity in fast-track total hip (THA) and knee arthroplasty (TKA). METHODS: Cohort study in consecutive unselected primary THA/TKA between 2014-2017 from seven Danish centers with established fast-track protocols. Preoperative comorbidity and prescribed medication were recorded prospectively and information on length of stay and readmissions was obtained through the Danish National Patient Registry and medical records. We used a machine-learning model (Boosted Decision Trees) based on boosted decision trees with 33 preoperative variables for predicting "medical" morbidity leading to LOS > 4 days or 90-days readmissions and compared to a logistical regression model based on the same variables. We also evaluated two parsimonious models, using the ten most important variables in the full machine-learning and logistic regression models. Data collected between 2014-2016 (n:18,013) was used for model training and data from 2017 (n:3913) was used for testing. Model performances were analyzed using precision, area under receiver operating (AUROC) and precision recall curves (AUPRC), as well as the Mathews Correlation Coefficient. Variable importance was analyzed using Shapley Additive Explanations values. RESULTS: Using a threshold of 20% "risk-patients" (n:782), precision, AUROC and AUPRC were 13.6%, 76.3% and 15.5% vs. 12.4%, 74.7% and 15.6% for the machine-learning and logistic regression model, respectively. The parsimonious machine-learning model performed better than the full logistic regression model. Of the top ten variables, eight were shared between the machine-learning and logistic regression models, but with a considerable age-related variation in importance of specific types of medication. CONCLUSION: A machine-learning model using preoperative characteristics and prescriptions slightly improved identification of patients in high-risk of "medical" complications after fast-track THA and TKA compared to a logistic regression model. Such algorithms could help find a manageable population of patients who may benefit most from intensified perioperative care.

No difference in short-term readmissions following day-case vs. one overnight stay in patients having hip and knee arthroplasty: a nationwide register study of 51,042 procedures from 2010-2020.

BACKGROUND AND PURPOSE: Day-case hip and knee arthroplasty has gained in popularity, but there are conflicting results regarding readmissions. We aimed to investigate differences in 30- and 90-day readmission rates between day-case patients and patients with a single overnight stay following primary total hip arthroplasty (THA), total knee arthroplasty (TKA), and unicompartmental knee arthroplasty (UKA). PATIENTS AND METHODS: We identified day-case (DC) and overnight (ON) THA, TKA, and UKA patients, operated on between 2010 and 2020, from the Danish National Patient Register. Day-case surgery was defined as discharge on the day of surgery. Overnight readmissions within 30 or 90 days of surgery were considered readmissions. We compared readmission rates between DC and ON patients within arthroplasty types using logistic regression adjusted for patient characteristics and year of surgery. We included 29,486 THAs (1,353 DC and 28,133 ON), 15,116 TKAs (617 DC and 14,499 ON), and 6,440 UKAs (1,528 DC and 4,914 ON). RESULTS: The 30-day readmission rates were: DC-THA 4.4% vs. ON-THA 4.4% (adjusted odds-ratio [aOR] 1.2, 95% confidence interval [CI] 0.91-1.6), DC-TKA 4.7% vs. ON-TKA 4.4% (aOR 1.1, CI 0.69-1.5), and DC-UKA 3.0% vs. ON-UKA 3.0% (aOR 1.1, CI 0.78-1.5). Similarly, no significant differences were present between DC and ON THA, TKA, and UKA regarding 90-day readmissions or time to readmission. CONCLUSION: We found no differences in readmission rates between day-case THA, TKA, and UKA patients and patients with a single overnight stay.

Effect of single versus multiple prophylactic antibiotic doses on prosthetic joint infections following primary total hip arthroplasty in patients with osteoarthritis at public and private hospitals in Denmark: protocol for a nationwide cross-over, cluster randomised, non-inferiority trial [The Pro-Hip-Quality Trial].

INTRODUCTION: A feared complication after total hip arthroplasty (THA) is prosthetic joint infection (PJI), associated with high morbidity and mortality. Prophylactic antibiotics can reduce the risk of PJI. However, there is no consensus on the dosages and current recommendations are based on a low evidence level. The objective is to compare the effect of a single versus multiple doses of prophylactic antibiotics administered within 24 hours on PJI. METHODS AND ANALYSIS: The study is designed as a cross-over, cluster randomised, non-inferiority trial. All clinical centres use both antibiotic practices (1 year of each intervention). All Danish orthopaedic surgery departments will be involved: Based on quality databases, 2-year cohorts of approximately 20 000 primary THAs conducted at 39 public and private hospitals, will be included. INCLUSION CRITERIA: age ≥18 years, all indications for THA except patients operated due to acute or sequelae from proximal femoral or pelvic fractures or bone tumour or metastasis. The primary outcome is PJI within 90 days after primary THA. Secondary outcomes include (1) serious adverse events, (2) potential PJI, (3) length of hospitalisation stay, (4) cardiovascular events, (5) hospital-treated infections, (6) community-based antibiotic use, (7) opioid use and (8) use of acetaminophen and non-steroidal anti-inflammatory drugs. All outcome measures will be extracted from national databases. Analyses will be based on the intention-to-treat population. Non-inferiority will be shown if the upper limit of the two-sided 95% CI for the OR is less than 1.32 for the single dose as compared with multiple doses. The results will establish best practice on antibiotic prophylaxis dosages in the future. ETHICS AND DISSEMINATION: This study has been approved by Committees on Health Research Ethics for The Capital Region of Denmark (21069108) and The Danish Medicines Agency (2021091723). All results will be presented in peer-reviewed medical journals and international conferences. TRIAL REGISTRATION NUMBER: NCT05530551.

Short-term surgical complications following fast-track medial unicompartmental knee arthroplasty.

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.

Complications after lateral unicompartmental knee arthroplasty in a fast-track setting: a prospective cohort study of 170 procedures.

BACKGROUND AND PURPOSE: In existing studies on fasttrack unicompartmental knee arthroplasty (UKA), the majority of surgeries are medial. There are substantial differences between lateral and medial UKA, which is why outcomes cannot automatically be compared. To gain information on the feasibility and safety of fast-track protocols in lateral UKAs, we investigated length of stay (LOS) and early complications after lateral UKA, performed using a fast-track protocol in well-established fast-track centers. PATIENTS AND METHODS: We retrospectively evaluated prospectively collected data on patients undergoing lateral UKA in a fast-track setup from 2010 to 2018 at 7 Danish fast-track centers. Data on patient characteristics, LOS, complications, reoperations, and revisions was analyzed using descriptive statistics. Safety and feasibility were defined as complication and reoperation rates within 90 days comparable to non-fast track lateral UKA or fast-track medial UKA. RESULTS: We included 170 of patients with a mean age of 66 (SD 12) years. Median LOS was 1 day (interquartile range 1-1), which was unchanged from 2012-2018. 18% were discharged on the day of surgery. Within 90 days, 7 patients experienced medical complications and 5 patients experienced surgical complications. 3 patients underwent reoperation, 2 were soft tissue revisions and the third was removal of an exostosis due to catching of the patella. 1 patient was revised due to a bearing dislocation. CONCLUSION: Our findings suggest that lateral UKA in a fast-track setting is feasible and safe.

High dose dexamethasone in high pain responders undergoing total hip arthroplasty: A randomized controlled trial.

BACKGROUND: Postoperative pain after total hip arthroplasty (THA) may delay postoperative mobilization and discharge. Postoperative pain has been shown to be higher in pain catastrophisers and patients receiving opioids. A single dose of glucocorticoid reduces pain after THA, and an increased dose of glucocorticoids has been found to be effective in patients at high risk of postoperative pain after total knee arthroplasty (TKA), however, the ideal dose in THA remains unknown. OBJECTIVE: To evaluate the effect of a high dose (1 mg kg -1 ) vs. intermediate dose (0.3 mg kg -1 ) of dexamethasone on pain after THA. DESIGN: A randomized double-blind controlled study. SETTING: A two-centre study including two large arthroplasty sites in Denmark was conducted from February 2019 to August 2020. PATIENTS: A total of 160 patients undergoing THA by neuraxial block with multimodal analgesia, having a Pain Catastrophising Scale score >20 and/or preoperative opioid use were included. INTERVENTION: Patients were randomly assigned to receive dexamethasone 1 mg kg -1 or 0.3 mg kg -1 before THA. MAIN OUTCOME MEASURES: Primary outcome was percentage of patients experiencing moderate to severe pain (visual analogue scale, VAS > 30 mm on a 0 to 100 mm scale) on ambulating 24 h after surgery. Secondary outcomes included cumulated pain scores, C-reactive protein (CRP), opioid use, postoperative recovery scores, length of stay, complications, and re-admission within 30 and 90 days. RESULTS: No difference was found in percentage of VAS >30 mm 24 h after surgery in the 5-m walk test (VAS > 30/VAS ≤ 30%); 33/42 (44%) vs. 32/43 (43%), relative risk = 1.04 (95% confidence interval 0.72-1.51; P  = 0.814) in 1 mg kg -1vs. 0.3 mg kg -1 respectively. No differences were found in CRP and opioid use between groups. Also, no intergroup differences were found in recovery scores, re-admissions, or complications. CONCLUSION: 1 mg kg -1vs. 0.3 mg kg -1 dexamethasone improved neither postoperative pain nor recovery in THA in a cohort of predicted high pain responders. TRIAL REGISTRATION: ClinicalTrials.gov ID-number NCT03763760 and EudraCT-number 2018-2636-25.

10-year evolution of day-case hip and knee arthroplasty: a Danish nationwide register study of 166,833 procedures from 2010 to 2020.

BACKGROUND AND PURPOSE: No previous studies have investigated the use of day-case arthroplasty in Denmark on a national scale. We investigated the frequency of day-case surgery in total hip (THA), total knee (TKA), and unicompartmental knee arthroplasty (UKA) from 2010 to 2020 in Denmark. PATIENTS AND METHODS: Primary unilateral THAs, TKAs, and UKAs performed for osteoarthritis were identified in the Danish National Patient Register using procedural and diagnosis codes. Day-case surgery was defined as discharge on the day of surgery. 90-day readmissions were defined as any overnight admissions following discharge. RESULTS: From 2010 to 2020 Danish surgical centers performed 86,070 THAs, 70,323 TKAs, and 10,440 UKAs. From 2010 to 2014, less than 0.5% of THAs and TKAs were day-case procedures. They increased to 5.4% (95% confidence interval [CI] 4.9-5.8) of THAs and 2.8% (CI 2.4-3.2) of TKAs in 2019. From 2010 to 2014, 11% of UKAs were day-case procedures, but they increased to 20% (CI 18-22) in 2019. This increase was driven by a few surgical centers (3-7 centers). In 2010, readmission rates within 90 days of surgery were 10% after THAs and 11% after TKAs, and 9.4% for both THAs and TKAs in 2019. Readmission rates after UKA fluctuated between 4% and 7%. CONCLUSION: From 2010 to 2020 the use of day-case surgery in THA, TKA, and UKA increased in Denmark, driven by only a few centers. During the same period readmissions did not increase.

Study protocol for discharge on day of surgery after hip and knee arthroplasty from the Center for Fast-track Hip and Knee Replacement.

BACKGROUND AND PURPOSE: Limited data exists on the implementation process and safety of discharge on the day of surgery after primary hip and knee arthroplasty in a multicenter setting. We report our study protocol on the investigation of the feasibility, safety, and socioeconomic aspects following discharge on day of surgery after hip and knee arthroplasty across 8 fast-track centers. PATIENTS AND METHODS: This is a study protocol for a prospective cohort study on discharge on day of surgery from the Center for Fast-track Hip and Knee Replacement. The collaboration includes 8 centers covering 40% of the primary hip and knee arthroplasty procedures undertaken in Denmark. All patients scheduled for surgery are screened for eligibility using well-defined inclusion and exclusion criteria. Eligible patients fulfilling discharge criteria will be discharged on day of surgery. We expect to screen 9,000 patients annually. Duration and outcome: Patients will be enrolled over a 3-year period from September 2022 and reporting of results will run continuously until December 2025. We shall report the proportion of eligible patients and patients discharged on day of surgery as well as limiting factors. Readmissions and complications within 30 days are recorded with real-time follow-up by research staff. Furthermore, patient-reported information on willingness to repeat discharge on day of surgery, contacts with the healthcare system, complications, and workability is registered 30 days postoperatively. EQ-5D, Oxford Knee Score, and Oxford Hip Score are completed preoperatively and after 3 months and 1 year. Finally, outcome data will be used in the development of a prediction model for successful discharge on the day of surgery.

Interpretation Threshold Values for the Oxford Hip Score in Patients Undergoing Total Hip Arthroplasty: Advancing Their Clinical Use.

BACKGROUND: Patient-reported outcome measures such as the Oxford Hip Score (OHS) can capture patient-centered perspectives on outcomes after total hip arthroplasty (THA). The OHS assesses hip pain and functional limitations, but defining interpretation threshold values for the OHS is warranted so that numerical OHS values can be translated into whether patients have experienced clinically meaningful changes. Therefore, we determined the minimal important change (MIC), patient acceptable symptom state (PASS), and treatment failure (TF) threshold values for the OHS at 12 and 24-month follow-up in patients undergoing THA. METHODS: This cohort study used data from patients undergoing THA at 1 public hospital between July 2016 and April 2021. At 12 and 24 months postoperatively, patients provided responses for the OHS and for 3 anchor questions about whether they had experienced changes in hip pain and function, whether they considered their symptom state to be satisfactory, and if it was not satisfactory, whether they considered the treatment to have failed. The anchor-based adjusted predictive modeling method was used to determine interpretation threshold values. Baseline dependency was evaluated using a new item-split method. Nonparametric bootstrapping was used to determine 95% confidence intervals (CIs). RESULTS: Complete data were obtained for 706 (69%) of 1,027 and 728 (66%) of 1,101 patients at 12 and 24 months postoperatively, respectively. These patients had a median age of 70 years, and 55% to 56% were female. Adjusted OHS MIC values were 6.3 (CI, 4.6 to 8.1) and 5.2 (CI, 3.6 to 6.7), adjusted OHS PASS values were 30.6 (CI, 29.0 to 32.2) and 30.5 (CI, 29.3 to 31.8), and adjusted OHS TF values were 25.5 (CI, 22.9 to 27.7) and 27.0 (CI, 25.2 to 28.8) at 12 and 24 months postoperatively, respectively. MIC values were 5.4 (CI, 2.1 to 9.1) and 5.0 (CI, 1.9 to 8.7) higher at 12 and 24 months, respectively, in patients with a more severe preoperative state. CONCLUSIONS: The established interpretation threshold values advance the interpretation and clinical use of the OHS, and may prove especially beneficial for registry-based evaluations of treatment quality. LEVEL OF EVIDENCE: Prognostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Repeat dose steroid in high pain responders after total knee arthroplasty: A study protocol.

Pain after total knee arthroplasty (TKA) is a well-known clinical problem potentially delaying ambulation and recovery. Perioperative glucocorticoids reduce pain and facilitate early recovery, but the optimal timing and dose are still unknown. High pain catastrophizers have an increased risk of poorly controlled postoperative pain, and moderate to severe pain at 24 h is associated with a risk of pain relapse at 48 h. To evaluate the effect of a repeat moderate dose of glucocorticoids after TKA in high pain catastrophizers presenting with moderate to severe pain 24 h postoperatively, having received preoperative high-dose glucocorticoids. High pain catastrophizers (Pain Catastrophizing Scale > 20) undergoing TKA are screened 24 h postoperatively and are included if they experience moderate to severe pain (VAS > 30) during a 5 m walk test. The included patients will receive either oral 24 mg dexamethasone (n = 55) or placebo (n = 55) on the evening of Day 1 (~30-37 h) after surgery. In addition, patients receive a standard multimodal analgesic regimen, including paracetamol, celecoxib, local infiltration analgesia, and preoperative dexamethasone (1 mg/kg). Patients will fill out a pain diary for 7 days after surgery. The primary outcome is moderate to severe pain (VAS > 30) during a 5 m walk test on the morning of Day 2 after surgery. The secondary outcomes include cumulated pain at rest and during ambulation, cumulated use of rescue analgesics, quality of sleep, lethargy, dizziness, nausea, satisfaction with the analgesic regimen, length of stay, morbidity, mortality, and reasons for readmissions. Follow-up is at 8 and 30 days. The data from this study will provide evidence for the effect of a repeated dose of dexamethasone as an analgesic adjuvant in patients undergoing TKA with a high risk of postoperative pain.

Genome-wide association meta-analysis of knee and hip osteoarthritis uncovers genetic differences between patients treated with joint replacement and patients without joint replacement.

OBJECTIVES: Osteoarthritis is a common and severe, multifactorial disease with a well-established genetic component. However, little is known about how genetics affect disease progression, and thereby the need for joint placement. Therefore, we aimed to investigate whether the genetic associations of knee and hip osteoarthritis differ between patients treated with joint replacement and patients without joint replacement. METHODS: We included knee and hip osteoarthritis cases along with healthy controls, altogether counting >700 000 individuals. The cases were divided into two groups based on joint replacement status (surgical vs non-surgical) and included in four genome-wide association meta-analyses: surgical knee osteoarthritis (N = 22 525), non-surgical knee osteoarthritis (N = 38 626), surgical hip osteoarthritis (N = 20 221) and non-surgical hip osteoarthritis (N = 17 847). In addition, we tested for genetic correlation between the osteoarthritis groups and the pain phenotypes intervertebral disc disorder, dorsalgia, fibromyalgia, migraine and joint pain. RESULTS: We identified 52 sequence variants associated with knee osteoarthritis (surgical: 17, non-surgical: 3) or hip osteoarthritis (surgical: 34, non-surgical: 1). For the surgical phenotypes, we identified 10 novel variants, including genes involved in autophagy (rs2447606 in ATG7) and mechanotransduction (rs202127176 in PIEZO1). One variant, rs13107325 in SLC39A8, associated more strongly with non-surgical knee osteoarthritis than surgical knee osteoarthritis. For all other variants, significance and effect sizes were higher for the surgical phenotypes. In contrast, genetic correlations with pain phenotypes tended to be stronger in the non-surgical groups. CONCLUSIONS: Our results indicate differences in genetic associations between knee and hip osteoarthritis depending on joint replacement status.

Peripheral nerve-blocks and associations with length of stay and readmissions in fast-track total hip and knee arthroplasty.

BACKGROUND: Peripheral nerve blocks (PNB) have recently been recommended in total hip (THA) and knee (TKA) arthroplasty as they may reduce pain, morphine consumption, length of stay (LOS) and complications. However, whether PNBs are associated with early discharge within an enhanced recovery protocol including multimodal analgesia is uncertain. METHODS: An observational multicenter study from January to August 2017 in six Danish Arthroplasty Centers with established fast-track protocols. Prospective recording of preoperative characteristics and information on PNB, LOS and readmissions through the Danish National Patient Registry and medical records. Multiple logistic regression was used to investigate associations between PNB and a LOS >1 day, LOS >4 days, and 30-days readmissions. We also reported on mobilization, pain, opioid and fall-related complications leading to LOS >4 days or readmissions. RESULTS: A total of 2027 (58.6%) THA and 1432 (41.4%) TKAs with a median LOS of 1 day (IQR 1-2) and 5.3% (CI:4.6-6.1) 30-days readmission rate were identified. PNB was used in 40.7% (CI:38.2-43.3) of TKA and 2.7% (CI:2.0-3.5) of THA, but with considerable interdepartmental variation (0.0-89.0% for TKA). There was no association between PNB and LOS >1 day (OR:1.19 CI:0.82-1.72; p = .354), LOS >4 days (OR:1.4 CI:0.68-2.89; p = .359) or 30-days readmissions (OR:1.02 CI:0.63-1.65; p = .935) in TKA. Logistic regression in THA was not possible due to limited use of PNB. In TKA there were 12 (2.1% CI:1.2-3.6) with and 1 (0.1% CI:0.02-0.7) without a PNB, who had mobilization, pain or opioid-related complications, and 5 (0.9% CI:0.4-2.0) versus 4 (0.5% CI:0.2-1.2) who fell. Correspondingly, 2 (3.7% CI:1.0-12.6) and 11 (0.6% CI:0.3-1.0) of THA patients had these complications, while 0 (0.0% CI:0.0-6.6) and 17 (0.8% CI:0.5-1.3) fell. CONCLUSION: Routine use of peripheral nerve blocks was not associated with early discharge or 30-days readmissions in fast-track THA and TKA. Future studies should focus on benefits of PNB in high-risk patients.

High-dose dexamethasone in low pain responders undergoing total knee arthroplasty: a randomised double-blind trial.

BACKGROUND: Postoperative pain after total knee arthroplasty (TKA) is a continuing problem despite optimised multimodal analgesia. Previous studies have shown preoperative glucocorticoids to reduce postoperative pain, but knowledge about specific doses and effects in specific patient groups is lacking. METHODS: A two-centre, double-blind, two-arm study comparing preoperative dexamethasone (1 mg kg-1vs 0.3 mg kg-1 i.v.) on postoperative pain in 160 planned TKA subjects with low preoperative pain catastrophising and no opioid use. Subjects received multimodal analgesia with paracetamol, cyclooxygenase-2 inhibitors, local anaesthetic infiltration analgesia, and rescue opioids. The primary outcome was percentage of subjects experiencing moderate to severe pain (visual analogue scale >30 mm) upon ambulation at 24 h. Secondary outcomes included pain scores, postoperative inflammation (C-reactive protein), opioid and antiemetics use, and 'Quality of Recovery-15' and 'Opioid-Related Symptom Distress Scale', length of stay, readmissions, and complications up to Day 90. RESULTS: A total of 157 subjects (80 vs 77) were included. No difference was found between groups in the incidence of subjects experiencing visual analogue scale >30 on ambulation 24 h after surgery (56% vs 53%, relative risk =1.07, confidence interval: 0.8-1.4, P=0.65). No differences in other pain outcomes or use of rescue opioids and antiemetics, in Quality of Recovery-15 and Opioid-Related Symptom Distress Scale, length of stay, readmissions, or complications. C-reactive protein values were comparable at 24 h (13 [6-25] mg L-1vs 16 [9-38] mg L-1, P = 0.07), but lower at 48 h (26 [9-52] mg L-1vs 50 [30-72] mg L-1, P<0.01) in the high-dose group. CONCLUSION: Use of 1 mg kg-1vs 0.3 mg kg-1 i.v. dexamethasone in low pain responders after TKA did not improve early postoperative pain or other outcomes in contrast to benefits in a high pain responder population. CLINICAL TRIAL REGISTRATION: NCT03758170 (first registration 29-11-2018).