"Pain without loosening"-revisions of knee arthroplasties in the Danish Knee Arthroplasty Register.

INTRODUCTION: We aimed to investigate "pain without loosening" as an indication for knee arthroplasty revisions and to screen for other indications potentially hidden in this category to improve future registration and enhance data quality in the Danish Knee Arthroplasty Register. METHODS: We included 104 patients undergoing revision knee arthroplasty for the indication "pain without loosening" from 1 January 2016 to 31 December 2018 at five Danish centres. Medical records, radiographs and computed tomographies were reviewed. RESULTS: In 103 of 104 cases, we confirmed "pain without loosening" as an indication for revision. We found hidden indications in 44 cases; malposition of components (n = 19), stiffness (n = 13), progression of arthrosis (n = 6), instability (n = 3), liner dislocation (n = 1), residual cement (n = 1) and aseptic loosening (n = 1). The Kellgren-Lawrence arthrosis grades prior to primary knee arthroplasty were 1-2 (31%) and 3-4 (69%). CONCLUSIONS: The indication "pain without loosening" covered patients revised due to pain, but other hidden indications were also present. Stiffness and malposition of components were hidden indications and these are not provided as indication options in the DKR and other registers. The relatively high frequency of arthrosis grade 1-2 prior to primary knee arthroplasty is concerning and may explain the occurrence of knee pain without any other pathology present. FUNDING: The Danish Rheumatism Association, the Region of Southern Denmark, the Research Fund of Region Zeeland and Region of Southern Denmark, and the University of Southern Denmark. TRIAL REGISTRATION: Not relevant.

Prolonged effects of dexamethasone following total knee arthroplasty: A pre-planned sub-study of the DEX-2-TKA trial.

OBJECTIVES: The DEX-2-TKA trial demonstrated that one and two doses of 24 mg intravenous dexamethasone reduced opioid consumption and pain after total knee arthroplasty (TKA). We aimed to investigate the prolonged effects of dexamethasone after the 48-h intervention period. DESIGN: This was a prospective, pre-planned questionnaire follow-up on postoperative days 3-7 of patients in the DEX-2-TKA trial that randomly received: DX1 (dexamethasone 24 mg + placebo), DX2 (dexamethasone 24 mg + dexamethasone 24 mg), and placebo (placebo + placebo) perioperatively and 24 h later. SETTING: A multicenter trial performed at five Danish hospitals. PARTICIPANTS: We analyzed 434 of 485 adult participants enrolled in the DEX-2-TKA trial. OUTCOME MEASURES: Primary outcome was difference between groups in average of all numerical rating scale (NRS) pain scores reported in the morning, at bedtime, and the daily average pain on postoperative days 3-7. Secondary outcomes were sleep quality and patient satisfaction. RESULTS: The median (interquartile range) pain intensity levels for postoperative days 3-7 were: DX2 3.2 (2.1-4.3); DX1 3.3 (2.3-4.1); and placebo 3.3 (2.5-4.7). Hodges-Lehmann median differences between groups were: 0 (95% confidence interval - 0.54 to 0.2), P = 0.38 between DX1 and placebo; 0.1 (-0.47 to 0.33), p = .87 between DX1 and DX2; and 0.1 (-0.6 to 0.13), p = .20 between DX2 and placebo. We found no relevant differences between groups on sleep quality on postoperative days 3-7 nor for patient satisfaction with the analgesic treatment. CONCLUSIONS: We found that neither one nor two doses of 24 mg intravenous dexamethasone demonstrated prolonged effects on overall pain or sleep quality on postoperative days 3-7 after total knee arthroplasty. We also found that dexamethasone had no effect on patient satisfaction. TRIAL REGISTRATION NUMBER: Clinicaltrials.gov NCT03506789 (main result trial).

Patient-reported outcomes and satisfaction after revisions of medial unicompartmental knee arthroplasties for unexplained pain vs aseptic loosening.

PURPOSE: Does patients revised for unexplained pain after mUKA present the same PROM and satisfaction scores 1-3 years after revision as patients revised for aseptic loosening?". METHODS: 104 patients undergoing revision of mUKA's for the indications unexplained pain and aseptic loosening were included in the period January 1, 2018 to December 31, 2020. from the Danish Knee Arthroplasty Register. 52 patients were revised for unexplained pain and 52 for aseptic loosening. Patient demographics did not differ between the two groups. PROMs [Oxford Knee Score (OKS), EQ-5D-5L, Forgotten Joint Score (FJS)] and questions about satisfaction with the surgery were sent to digitally secured mailboxes. Pearson's Chi-square test and Wilcoxon Rank Sum test were used to test for statistical differences between groups. RESULTS: The median OKS 1-3 years after revision was 26 (IQR 22) for unexplained pain vs 34 (IQR 12) for aseptic loosening, p = 0.033. The median EQ-5D-5L Index after revision was 0.7 (IQR 0.6) for unexplained vs 0.8 (IQR 0.1) for aseptic loosening, p = 0.014. The median FJS after revision was 48 (IQR 10) for unexplained pain vs 52 (IQR 14) for aseptic loosening, p = 0.1. The mean satisfaction with the surgery on a 0-100 scale (100 = not satisfied; 0 = very satisfied) was 55 (IQR 60) for unexplained pain vs 50 (IQR 67) for aseptic loosening, p = 0.087, and patients revised for unexplained pain were less likely to find their knee problem importantly improved (p = 0.032). CONCLUSION: Patients undergoing revision of mUKAs for unexplained pain presented poor postoperative PROM scores, and PROM scores were worse compared to those of patients revised for aseptic loosening. Patients revised for unexplained pain were less likely to find their knee problem importantly improved. This study support the evidence against revisions for unexplained pain. LEVEL OF EVIDENCE: Level III.

Patient-Reported Outcomes and Satisfaction 1 to 3 Years After Revisions of Total Knee Arthroplasties for Unexplained Pain Versus Aseptic Loosening.

BACKGROUND: It is unknown if patients are relieved of pain after knee arthroplasty revision for unexplained pain. The aim of this cross-sectional case-control study was to compare patient-reported outcome measures (PROMs) and satisfaction 1 to 3 years after revision of total knee arthroplasties (TKAs) for the indications of unexplained pain versus aseptic loosening. METHODS: We included 384 patients undergoing TKA revision for the indications of unexplained pain and aseptic loosening from January 1, 2018 to December 31, 2020 from the Danish Knee Arthroplasty Register. A total of 81 patients were revised for unexplained pain and 303 for aseptic loosening. Questionnaires including PROMs (Oxford Knee Score, EQ-5D-5L, and Forgotten Joint Score) and satisfaction with the surgery on a 0-100 scale (100 = not satisfied; 0 = very satisfied) were sent to digitally secured mailboxes. Time from revision to data collection was a median 3.1 years (range, 1.4-4.4 years). RESULTS: Median Oxford Knee Score was 25 (interquartile range [IQR] 15) versus 31 (IQR 18) 1-3 years after revisions for unexplained pain versus aseptic loosening, P = .009. Median EQ-5D-5L was 0.6 (IQR 0.4) versus 0.8 (IQR 0.3) for unexplained pain versus aseptic loosening, P = .009. Median Forgotten Joint Score was 50 (IQR 7) versus 50 (IQR 16) for unexplained pain versus aseptic loosening, P = .905. Satisfaction was 75 (IQR 38) for unexplained pain and 50 (IQR 73) for aseptic loosening, P < .001. CONCLUSION: Patients undergoing TKA revision for the indication of unexplained pain had worse results on PROMs than those revised for aseptic loosening. Likewise, patients revised for unexplained pain were less satisfied compared to patients revised for aseptic loosening. This information is valuable to both surgeons and patients when candidates for revision surgery are selected, to obtain the best possible outcomes.

Effect of dexamethasone as an analgesic adjuvant to multimodal pain treatment after total knee arthroplasty: randomised clinical trial.

OBJECTIVE: To investigate the effects of one and two doses of intravenous dexamethasone in patients after total knee arthroplasty. DESIGN: Randomised, blinded, placebo controlled trial with follow-up at 90 days. SETTING: Five Danish hospitals, September 2018 to March 2020. PARTICIPANTS: 485 adult participants undergoing total knee arthroplasty. INTERVENTION: A computer generated randomised sequence stratified for site was used to allocate participants to one of three groups: DX1 (dexamethasone (24 mg)+placebo); DX2 (dexamethasone (24 mg)+dexamethasone (24 mg)); or placebo (placebo+placebo). The intervention was given preoperatively and after 24 hours. Participants, investigators, and outcome assessors were blinded. All participants received paracetamol, ibuprofen, and local infiltration analgesia. MAIN OUTCOME MEASURES: The primary outcome was total intravenous morphine consumption 0 to 48 hours postoperatively. Multiplicity adjusted threshold for statistical significance was P<0.017 and minimal important difference was 10 mg morphine. Secondary outcomes included postoperative pain. RESULTS: 485 participants were randomised: 161 to DX1, 162 to DX2, and 162 to placebo. Data from 472 participants (97.3%) were included in the primary outcome analysis. The median (interquartile range) morphine consumptions at 0-48 hours were: DX1 37.9 mg (20.7 to 56.7); DX2 35.0 mg (20.6 to 52.0); and placebo 43.0 mg (28.7 to 64.0). Hodges-Lehmann median differences between groups were: -2.7 mg (98.3% confidence interval -9.3 to 3.7), P=0.30 between DX1 and DX2; 7.8 mg (0.7 to 14.7), P=0.008 between DX1 and placebo; and 10.7 mg (4.0 to 17.3), P<0.001 between DX2 and placebo. Postoperative pain was reduced at 24 hours with one dose, and at 48 hours with two doses, of dexamethasone. CONCLUSION: Two doses of dexamethasone reduced morphine consumption during 48 hours after total knee arthroplasty and reduced postoperative pain. TRIAL REGISTRATION: Clinicaltrials.gov NCT03506789.

Muscle Function Tests as Supportive Outcome Measures for Performance-Based and Self-Reported Physical Function in Patients With Knee Osteoarthritis: Exploratory Analysis of Baseline Data From a Randomized Trial.

ABSTRACT: Holm, PM, Kemnitz, J, Bandholm, T, Wernbom, M, Schrøder, HM, and Skou, ST. Muscle function tests as supportive outcome measures for performance-based and self-reported physical function in patients with knee osteoarthritis: Exploratory analysis of baseline data from a randomized trial. J Strength Cond Res 36(9): 2635-2642, 2022-Uncertainty on the role of muscle function in relation to physical function in knee osteoarthritis (KOA) persists. This study aimed to assess the associations between muscle function and performance-based and self-reported physical function in patients with KOA. Physical function in 80 subjects with symptomatic and radiographic KOA was assessed using 40-m fast-paced walk, 30-second chair stand, 9-step stair climb tests, and the subscale activities of daily living from the Knee injury and Osteoarthritis Outcome Score (KOOS-ADL). Measurements of muscle function included leg extension (LE) power, knee extension (KE) torque, and estimated leg press one repetition maximum (LP RM). Associations were investigated using multivariable hierarchical linear regressions adjusted for age, sex, body mass index, self-reported physical activity, and thigh muscle lean area. Leg extension power was significantly associated with 40-m walk, stair climb, and 30-second chair stand, explaining 18, 8, and 3% of additional variance, respectively. Knee extension torque explained 13, 7, 17, and 7% of additional variance in the 40-m walk, stair climb, 30-second chair stand, and KOOS-ADL, respectively. Leg press one repetition maximum explained 11% of additional variance in the 30-second chair stand. In conclusion, LE power was the best explanatory variable for performance on the 40-m walk and stair climb tests, whereas KE torque best explained chair stand performance. Only KE torque was associated with KOOS-ADL. Our results highlight the importance of selecting supportive muscle function tests based on the specific physical function and suggest that other factors may be more important for certain physical function outcomes. Level of significance p < 0.05. Trial identifier: NCT03215602.

Establishing research priorities related to osteoarthritis care via stakeholder input from patients.

INTRODUCTION: Stakeholder involvement in research is emphasised to improve relevance. We aimed to identify, define and prioritise important research topics seen from the point of view of people with osteoarthritis (OA). METHODS: We invited 1,315 members of the user panel of the Danish Rheumatism Association to answer an electronic survey that included; 1) an open-ended question about important research topics (free-text response option), 2) 15 predefined research topics to be rated for importance and 3) predefined topics grouped into four categories in which the most important was prioritised. Free-text responses were analysed using content analysis. RESULTS: Out of 850 (65%) respondents, 483 had OA (mean ± standard deviation age 60.3 ± 10.2 years, 91% female). From the free-text responses, we identified seven research topics; 1) diagnostics, 2) prevention, 3) side effects, 4) treatment, 5) aetiology, 6) being young with OA and 7) quality of life. For "treatment", we identified seven subtopics. Out of all topics and subtopics, "pain management" was the most frequently highlighted. All predefined topics were rated as "very important" or "somewhat important" by more than 75% of the respondents. The top prioritised topics within each category were 1) improving the diagnosis, 2) individualised treatment, 3) shared decision-making and 4) cross-sector collaboration and collaboration between professionals. CONCLUSIONS: We identified research topics that were important in the eyes of people with OA and found that "pain management" was particularly emphasised. FUNDING: none. TRIAL REGISTRATION: not relevant.

One-stage versus two-stage revision of the infected knee arthroplasty - a randomized multicenter clinical trial study protocol.

BACKGROUND: A two-stage prosthesis exchange procedure has been the gold standard in surgical treatment of the chronically infected knee arthroplasty so far. This includes 2 surgeries/hospitalizations and an interim period of 2-3 months between surgeries with impaired health, functional status and quality of life of the patients. A one-stage exchange procedure holds many obvious advantages compared to the two-stage approach, but outcomes of a one-stage versus two-stage procedures have never been investigated in a randomized clinical trial. The purpose of this study is primarily to investigate time-adjusted differences in functional status of patients after one-stage versus two-stage revision. Secondary, to report time-adjusted differences in quality of life, complications (including re-revisions due to infection) and mortality. METHODS: This study is a pragmatic, multi-center, randomized, non-inferiority trial comparing one-stage versus two-stage revision of the infected knee arthroplasty. Seven Danish hospitals are currently participating in the study, but additional hospitals can enter the study if adhering to protocol. Ninety-six patients will be included prospectively. Follow-up will be with PROM-questionnaires and clinical controls up to 10 years. The patients who are not able to participate in the randomized trial are followed in a parallel cohort study. PROM'S: Oxford Knee Score and EQ5D + EQ5D VAS questionnaires are completed preoperatively and sent out to the study participants at 6 weeks, 3, 6, 9, 12, 18 and 24 months as well as 5 and 10 years postoperatively. In addition a tailor made cost questionnaire on the non-treating hospital resource use, community health and social service use, travel costs, time off work and informal care are sent out. DISCUSSION: If one of the two treatment alternatives is found superior in both domains of quality of life (both knee-specific and generic) and health economics, that treatment should be promoted. Other outcomes will open informed discussions about treatment strategies for periprosthetic knee infections. TRIAL REGISTRATION: The randomized trial is registered on ClinicalTrials.gov with ID NCT03435679 , initial release date January 31, 2018 and the cohort study is registered with ID NCT04427943 , submitted January 8, 2020 and posted June 11, 2020.

Intrarater Reliability and Agreement of Recommended Performance-Based Tests and Common Muscle Function Tests in Knee Osteoarthritis.

BACKGROUND AND PURPOSE: Some uncertainty persists regarding the reproducibility of the recommended core set of performance-based tests, as well as common muscle function tests, when applied in individuals with knee osteoarthritis (KOA). The purpose of this study was to investigate the intrarater reliability and agreement of the recommended core set of performance-based tests and common muscle function tests in KOA. METHODS: Participants (N=40) with radiographic and/or symptomatic KOA were evaluated twice with a 3-day interval between test sessions using the following tests: Leg extensor (LE) maximal muscle power measured in a Nottingham Power Rig; knee extensor (KE) peak isometric strength measured with a handheld dynamometer; 40-m walk test; 30-second chair-stand test; and 9-step stair climb test. Reliability was assessed using a 2-way, mixed-effects, single-measures model (3,1), absolute agreement-type intraclass correlation coefficient (ICC). Agreement was assessed using 95% limits of agreement (LOA) and LOA relative to the mean score from test and retest (LOA-%). RESULTS: Reliability for all tests was very high (ICC ≥ 0.97). LOA (LOA-%) was ±32.3 watt (W) (±22%) for LE power; ±22.7 N·m (±24%) for KE strength; ±0.2 m/s (±10%) for 40-m walk test; ±2.4 repetitions (±14%) for 30-second chair-stand test; and ±2 second (±20%) for stair climb test. A potential participant learning effect was found for all 3 performance-based tests, indicated by the significantly better scores at retest. DISCUSSION: The very high reliability found for the performance-based tests supports findings from previous studies and confirms discriminate reliability of these tests on a group level. Also, very high reliability estimates were demonstrated for both muscle function tests. This study also provided estimates of agreement for both performance-based and muscle function tests, which are important to consider when using these tests on an individual level in clinical practice. CONCLUSION: When using these tests to monitor changes over time in the clinic, depending on the test, improvements of less than 10% to 24% could be a result of measurement error alone and therefore may not be considered an actual improvement after treatment.

Patient-reported outcomes of 7133 distal femoral, patellar, and proximal tibial fracture patients: A national cross-sectional study with one-, three-, and five-year follow-up.

BACKGROUND: Few studies have described patient-reported outcome measures (PROMs) in knee fracture patients. We reported knee-specific and generic median PROM scores after knee fracture and identified risk factors for poor outcome defined by low median PROM scores. METHODS: In a Danish cross-sectional study of 7133 distal femoral, patellar, and proximal tibial fracture patients during 2011-2017, OKS, FJS-12, EQ5D-5L Index, and EQ5D-5L Visual Analogue Scale (VAS), were collected electronically (response rate 53%; median age 60; 63% female). Poor outcome was defined as score lower than median PROM score. Poor outcome risk factors were estimated as odds ratios from binary logistic regression models. RESULTS: At 0 to one year after knee fracture, median PROM scores were 31 (OKS), 27 (FJS-12), 0.50 (EQ5D-5L Index), and 74 (EQ5D-5L VAS). At >5 years after knee fracture, median OKS score was 40, median FJS-12 score was 54, median EQ5D-5L Index was 0.76, and median EQ5D-5L VAS score was 80. Age > 40 years had higher odds for poor OKS and FJS-12 scores at short- and long-term follow-up after knee fracture. Comorbidity burden, distal femoral fracture, and treatment with external fixation and knee arthroplasty were risk factors for poor outcome at long-term follow-up, for all four PROMs. CONCLUSIONS: Although knee fracture patients have relatively high knee function and quality of life, their ability to forget about the knee joint after knee fracture is compromised. We identified several important risk factors for poor outcome measured by PROMs at different follow-up periods following knee fracture, which will help direct future quality-improvement initiatives.

Differences in patient characteristics and external validity of randomized clinical trials on pain management following total hip and knee arthroplasty: a systematic review.

BACKGROUND: The external validity of randomized controlled trials (RCTs) is critical for the relevance of trial results in a clinical setting. We aimed to assess the external validity of RCTs investigating postoperative pain treatment after total hip and knee arthroplasty (THA and TKA) by comparing patient characteristics in these trials with a clinical cohort. Further, we assessed the use of exclusion criteria of the included RCTs. METHODS: We searched PubMed, Embase, and Cochrane Central Register of Controlled Trials for relevant RCTs up to June 2019. Data on patient characteristics from this research population were compared with an unselected clinical cohort from the Danish Hip and Knee Arthroplasty Registries in the period 2005-2019. Trends in patient characteristics and the use of exclusion criteria were assessed with control charts. RESULTS: In total, 550 RCTs with 48 962 participants were included in the research cohort. The clinical cohort included 101 439 THA patients and 90 505 TKA patients. Patient characteristics (age, body mass index (BMI), American Society of Anesthesiologists (ASA) score and sex distribution) in the research cohort resembled those of the clinical cohort. Age, BMI and ASA scores did not change over time in the research cohort. In the clinical cohort, age increased among both THA and TKA patients, and BMI and ASA scores increased among TKA patients. Most commonly used exclusion criteria in the RCTs were high ASA score (62%), older age (45%), obesity (32%) and chronic opioid use (41%). Exclusion of chronic opioid users and individuals with obesity increased over time. CONCLUSION: Patient characteristics in research trials investigating postoperative pain management after THA and TKA currently resemble those of a clinical cohort. However, individuals in the clinical cohort are getting older, and TKA patients more obese with increasing ASA scores. Concomitantly, RCTs increase the tendency to exclude patients with older age, obesity, chronic pain and/or opioid use. This trending discrepancy can hinder the generalizability of future research results, and therefore increased focus on pragmatic trials resembling real-world conditions are needed. PROSPERO REGISTRATION NUMBER: CRD42019125691.

No-Fault Compensation From the Patient Compensation Association in Denmark After Primary Total Hip Replacement in Danish Hospitals 2005-2017.

BACKGROUND: There is an annually rising number of performed total hip arthroplasty (THA) surgeries in Denmark and this is expected to become even more common. However, there are still risks of adverse events, which become the basis for compensation claims. In Denmark, there are no studies available concerning filed claims after THA. The aims of this study are to determine the incidence of claims related to THAs in Denmark, the reasons to claim, which claims lead to compensation, the amount of compensation, and trends over time. METHODS: In this observational study, we analyzed all closed claims between 2005 and 2017 from the Danish Patient Compensation Association (DPCA). With the intention to contribute to prevention, we have identified the number and outcome of claims. RESULTS: There were 2924 cases (ie, 2.5% of all THAs performed in this period). The approval rate was 54%. The number of claims filed was stagnant over time, except for a spike of metal-on-metal (MoM) prosthesis cases. The total payout was USD 29,591,045, and 87% of this was due to nerve damage (USD 9,106,118), infection (USD 6,046,948), MoM prosthesis (USD 4,624,353), insufficient or incorrect treatment (USD 472,500), and fracture (USD 2,088,110). CONCLUSION: In total, 2.5% of all THAs performed between 2005 and 2017 lead to a claim submission at the DPCA. One of 2 claims were approved. The majority of payouts were due to nerve damage, infection, MoM prosthesis, insufficient or incorrect treatment, and fracture. Although DPCA manages claims for patients, the data can also provide beneficial feedback to arthroplasty surgeons with the aim of improving patient care.

20-year trends of distal femoral, patellar, and proximal tibial fractures: a Danish nationwide cohort study of 60,823 patients.

Background and purpose - Knee fracture treatment burden remains unknown, impeding proper use of hospital resources. We examined 20-year trends in incidence rates (IRs) and patient-, fracture-, and treatment-related characteristics of knee fracture patients.Patients and methods - This nationwide cohort study of prospectively collected data including patients with distal femoral, patellar, and proximal tibial fractures from the Danish National Patient Registry during 1998-2017, assesses IRs of knee fractures (per 105 inhabitants) as well as patient-, fracture-, and treatment-related characteristics of knee fracture patients.Results - During 1998-2017, 60,823 patients (median age 55; 57% female) sustained 74,106 knee fractures. 74% of the study population had a Charlson Comorbidity Index (CCI) of 0 and 18% a CCI of ≥ 2. 51% were proximal tibial fractures, 31% patellar fractures, and 18% distal femoral fractures. At the time of knee fracture, 20% patients had concomitant near-knee fractures (femur/tibia/fibula shaft/hip/ankle), 13% concomitant fractures (pelvic/spine/thorax/upper extremities), 5% osteoporosis, and 4% primary knee osteoarthritis. Over 1/3 knee fractures were surgically treated and of these 86% were open-reduction internal fixations, 9% external fixations, and 5% knee arthroplasties. The most common surgery type was proximal tibia plating (n = 4,868; 60% female). Knee fracture IR increased 12% to 70, females aged > 51 had the highest knee fracture IR, proximal tibial fracture had the highest knee fracture type IR (32) and surgically treated knee fracture IR increased 35% to 23.Interpretation - Knee fracture IRs, especially of surgically treated knee fractures, are increasing and proximal tibial fracture has the highest knee fracture type IR. Females aged > 51 and patients with comorbidity are associated with knee fracture, proximal tibial fracture, proximal tibial fracture surgery, and posttraumatic knee arthroplasty.

Randomized clinical trial of medial unicompartmentel versus total knee arthroplasty for anteromedial tibio-femoral osteoarthritis. The study-protocol.

BACKGROUND: In treatment of isolated medial unicondylar osteoarthritis of the knee, it is possible to choose between medial unicondylar knee arthroplasty (mUKA), or a total knee prosthesis (TKA). The demand for a blinded multicenter RCT with the comparison of mUKA and TKA has been increasing in recent years, to determine which prosthesis is better. Supporters of TKA suggest this treatment gives a more predictable and better result, whereas supporters of UKA suggest it is unnecessary to remove functional cartilage in other compartments. If the mUKA is worn or loosens, revision surgery will be relatively easy, whereas revision-surgery after a TKA can be more problematic. METHODS: A double-blinded multicenter Randomized Clinical Trial setup is the aim of the study. 6 hospitals throughout all 5 municipal regions of Denmark will be participating in the study. 350 patients will be included prospectively. Follow-up will be with PROM-questionnaires and clinical controls up to 20 years. DISCUSSION: Results will be assessed in terms of 1) PROM-questionnaires, 2) Clinical assessment of knee condition, 3) cost analysis. To avoid bias, all participants except the theatre-staff will be blinded. PROMS: OKS, KOOS, SF36, Forgotten Joint Score, EQ5D, UCLA activity scale, Copenhagen Knee ROM scale, and Anchor questions. Publications are planned at 2, 5 and 10 years after inclusion of the last patient. The development of variables over time will be analyzed by calculating the area under the curve (AUC) for the variable relative to the initial value, and comparisons of the between-group differences will be based on parametric statistics. In this study, we feel that we have designed a study that will address these concerns with a well-designed double-blinded multicentre RCT. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03396640 . Initial Release: 09/19/2017. Date of enrolment of first participant: 10/11/17.

Prospective psychometric characterization of hip and knee arthroplasty patients.

BACKGROUND: Psychiatric conditions and psychopharmacological treatments have been demonstrated to be important risk-factors for prolonged hospital length of stay, readmission and morbidity, following fast-track total hip (THA) and total knee arthroplasty (TKA). AIMS: The aim of the study was to provide a detailed description of the preoperative psychiatric characteristics of a well-defined patient population undergoing THA and TKA, using the 90-item Symptom Checklist (SCL-90-R). METHODS: A pre-surgical population of 2183 patients completed the full SCL-90-R prior to THA/TKA from 2015 to 2016. The SCL-90-R scale and total scores of the pre-surgical sample were compared to the scores of an age- and gender stratified Danish sample of healthy controls. A Mokken scalogram analysis was conducted to assess the scalability of the SCL-90-R in both samples. RESULTS: The Mokken analysis yielded acceptable scalability coefficients above 0.30 in all subscales of the SCL-90-R except psycoticism (0.28). There was no clinically significant difference (effect size = <0.50) in the SCL-90-R total score between the pre-surgical and the healthy controls samples, although pre-surgical patients had lower mean scores compared to the healthy controls in all subscales except somatization (effect size = -0.22). CONCLUSION: The Mokken analysis demonstrated that the SCL-90-R and its subscales express valid measures of psychopathology in our surgical sample. The psychiatric profile of the pre-surgical patient sample indicates that patients undergoing THA/TKA are not more burdened by psychiatric symptoms than a healthy control group with the exception of symptoms relating to somatization.

PANSAID-PAracetamol and NSAID in combination: detailed statistical analysis plan for a randomised, blinded, parallel, four-group multicentre clinical trial.

BACKGROUND: Effective postoperative pain management is essential for the rehabilitation of the surgical patient. The PANSAID trial evaluates the analgesic effects and safety of the combination of paracetamol and ibuprofen. This paper describes in detail the statistical analysis plan for the primary publication to prevent outcome reporting bias and data-driven analysis results. METHODS/DESIGN: The PANSAID trial is a multicentre, randomised, controlled, parallel, four-group clinical trial comparing the beneficial and harmful effects of different doses and combinations of paracetamol and ibuprofen in patients having total hip arthroplastic surgery. Patients, caregivers, physicians, investigators, and statisticians are blinded to the intervention. The two co-primary outcomes are 24-h consumption of morphine and proportion of patients with one or more serious adverse events within 90 days after surgery. Secondary outcomes are pain scores during mobilisation and at rest at 6 and 24 h postoperatively, and the proportion of patients with one or more adverse events within 24 h postoperatively. DISCUSSION: PANSAID will provide a large trial with low risk of bias regarding benefits and harms of the combination of paracetamol and ibuprofen used in a perioperative setting. TRIAL REGISTRATION: ClinicalTrials.org identifier: NCT02571361 . Registered on 7 October 2015.

PANSAID - PAracetamol and NSAID in combination: study protocol for a randomised trial.

BACKGROUND: Effective postoperative pain management is essential for the rehabilitation of the surgical patient. No 'gold standard' exists after total hip arthroplasty (THA) and combinations of different nonopioid medications are used with virtually no evidence for additional analgesic efficacy compared to monotherapy. The objective of this trial is to investigate the analgesic effects and safety of paracetamol and ibuprofen alone and in combination in different dosages after THA. METHODS: PANSAID is a placebo-controlled, parallel four-group, multicentre trial with centralised computer-generated allocation sequence and allocation concealment and with varying block size and stratification by site. Blinding of assessor, investigator, caregivers, patients and statisticians. Patients are randomised to four groups: (A) paracetamol 1 g × 4 and ibuprofen 400 mg × 4, (B) paracetamol 1 g × 4 and placebo, (C) placebo and ibuprofen 400 mg × 4 and (D) paracetamol 0.5 g × 4 and ibuprofen 200 mg. The two co-primary outcomes are 24-h consumption of morphine and number of patients with one or more serious adverse events within 90 days after surgery. Secondary outcomes are pain scores during mobilisation and at rest at 6 and 24 h postoperatively, and number of patients with one or more adverse events within 24 h postoperatively. Inclusion criteria are patients scheduled for unilateral, primary THA; age above 18 years; ASA status 1-3; BMI >18 and <40 kg/m2; women must not be pregnant; and provision of informed consent. Exclusion criteria are patients who cannot cooperate with the trial; participation in another trial; patients who cannot understand/speak Danish; daily use of strong opioids; allergy against trial medication; contraindications against ibuprofen; alcohol and/or drug abuse. A total of 556 eligible patients are needed to detect a difference of 10 mg morphine i.v. the first 24 h postoperatively with a standard deviation of 20 mg and a family wise type 1 error rate of 0.025 (two-sided) and a type 2 error rate of 0.10 for the six possible comparisons of the four intervention groups. DISCUSSION: We started recruiting patients in December 2015 and expect to finish in September 2017. Data analysis will be from September 2017 to October 2017 and manuscript submission ultimo 2017. TRIAL REGISTRATION: EudraCT: 2015-002239-16 (12/8-15); ClinicalTrials.gov: NCT02571361 . Registered on 7 October 2015.

Use of a New Knee Prosthesis as an Articulating Spacer in Two-Stage Revision of Infected Total Knee Arthroplasty.

PURPOSE: To report our experience with two-stage revision using a new femoral component (NFC) spacer (Depuy Synthes) as an articulating spacer. MATERIALS AND METHODS: In this retrospective study, we reviewed 22 two-stage revisions that were performed using an NFC spacer in 22 patients suspected of having an infected total knee arthroplasty (TKA) from December 2010 to March 2013. The result was considered successful when eradication of infection was achieved using only one NFC spacer. RESULTS: The average time from primary TKA to the first stage procedure was 29.1 months and the average time from the first stage procedure until the final second stage procedure was 12.7 weeks. The average range of motion increased from 82° preoperatively to 104° postoperatively. The American Knee Society Knee score increased from 29.3 points to 66 points. The Function score increased from 29.5 points to 64 points. Four cases were reinfected after two-stage revision. The mean follow-up was 37.6 months. CONCLUSIONS: The new articulating spacer showed promising short-term results both with regard to eradication of infection and functional improvement.