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.

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).

Safety of vitamin E-infused highwall liners for routine use in primary total hip arthroplasty: single centre, short-term follow-up of 1221 cases.

BACKGROUND: Introduction of new implants should be monitored closely to capture any signs of compromising patient safety. Vitamin E infused highly-crosslinked polyethylene liners (VEPE) offer the potential for reduced wear. Highwall liners have been hypothesised to result in increased wear and potential liner fractures. The aim of this study was to determine the 3-7-year follow-up of highwall VEPE for primary total hip arthroplasty (THA), focusing on liner-related complications. METHODS: We included 1221 consecutive THA operations from July 2010 to May 2014 with minimum follow-up of 3 (3.1-6.8) years Data collected included demographics, implant data, complications, reoperations, and deaths. Data were cross-referenced with the Danish Hip Arthroplasty Registry in order to ensure validity and completeness. Acetabular shell position was measured using Martell Hip Analysis Suite in a subgroup of 931 THAs. RESULTS: Cumulative stem revision and shell revision at 3-year follow-up was 3.4% and 0.4% respectively. There were no revisions due to liner failure. Reason for revision included 11 dislocations, 15 soft-tissue revisions for infection, 44 stem revisions of which 34 were periprosthetic fractures and 13 shell revisions of which 6 were combined shell and stem revisions. CONCLUSION: Early follow-up of VEPE liners for primary THA have not shown any revisions associated with liner failure. Continued monitoring of new materials are necessary to capture any signs of compromised patient safety.

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

BACKGROUND: Total knee arthroplasty (TKA) is associated with moderate-to-severe postoperative pain despite multimodal opioid-sparing analgesia. Pain catastrophising or preoperative opioid therapy is associated with increased postoperative pain. Preoperative glucocorticoid improves pain after TKA, but dose-finding studies and benefit in high pain responders are lacking. METHODS: A randomised double-blind controlled trial with preoperative high-dose intravenous dexamethasone 1 mg kg-1 or intermediate-dose dexamethasone 0.3 mg kg-1 in 88 patients undergoing TKA with preoperative pain catastrophising score >20 or regular opioid use was designed. The primary outcome was the proportion of patients experiencing moderate-to-severe pain (VAS >30) during a 5 m walk 24 h postoperatively. Secondary outcomes included pain at rest during nights and at passive leg raise, C-reactive protein, opioid use, quality of sleep, Quality of Recovery-15 and Opioid-Related Symptom Distress Scale, readmission, and complications. RESULTS: Moderate-to-severe pain when walking 24 h postoperatively was reduced (high dose vs intermediate dose, 49% vs 79%; P<0.01), along with pain at leg raise at 24 and 48 h (14% vs 29%, P=0.02 and 12% vs 31%, P=0.03, respectively). C-reactive protein was reduced in the high-dose group at both 24 and 48 h (both P<0.01). Quality of Recovery-15 was also improved (P<0.01). CONCLUSIONS: When compared with preoperative dexamethasone 0.3 mg kg-1 i.v., dexamethasone 1 mg kg-1 reduced moderate-to-severe pain 24 h after TKA and improved recovery in high pain responders without apparent side-effects. CLINICAL TRIAL REGISTRATION: NCT03763734.

No increase in postoperative contacts with the healthcare system following outpatient total hip and knee arthroplasty.

Background and purpose - Discharge on the day of surgery (DDOS) after total hip arthroplasty (THA) and total knee arthroplasty (TKA) has been shown to be safe in selected patients. Concerns have been raised that discharging patients on the day of surgery (DOS) could lead to an increased burden on other parts of the healthcare system when compared with patients not discharged on the DOS (nDDOS). Therefore, we investigated whether discharging patients on the day of surgery (DOS) after THA and TKA leads to increased contacts with the primary care sector or other departments within the secondary care sector.Patients and methods - Prospective data on 261 consecutive patients scheduled for outpatient THA (n = 135) and TKA (n = 126) were collected as part of a previous cohort study. 33% of THA patients and 37% of TKA patients were discharged on the DOS. Readmissions within 3 months after surgery were recorded. Contacts with the discharging department, other departments, and primary care physicians within 3 weeks were registered.Results - No statistically significant differences were found when comparing DDOS patients and patients not discharged on the DOS (nDDOS) with regard to readmissions, physical contacts with the discharging department, and contacts with other departments as well as general practitioners. THA DDOS patients had significantly fewer contacts with the discharging department by telephone than THA nDDOS patients. TKA DDOS patients had significantly more contacts with the discharging department by telephone than TKA nDDOS patients.Interpretation - Patients discharged on the DOS following THA or TKA generally have similar postoperative contacts with the healthcare system when compared with patients not discharged on the DOS.

Population pharmacokinetics of ropivacaine used for local infiltration anaesthesia during primary total unilateral and simultaneous bilateral knee arthroplasty.

BACKGROUND: Ropivacaine is commonly used in local infiltration anaesthesia (LIA) as pain management after total knee arthroplasty (TKA). Although considered safe, no studies evaluated the pharmacokinetics of high-dose ropivacaine infiltration in simultaneous bilateral TKA. METHODS: We studied 13 patients undergoing unilateral and 15 undergoing bilateral TKA. Standard LIA technique was used with ropivacaine 0.2%, 200 ml (400 mg) injected peri-articularly in each knee. Free and total plasma concentrations of ropivacaine were measured within 24 h using liquid chromatography-mass spectrometry. A population pharmacokinetic model was built using non-linear mixed-effects models. RESULTS: Peak free ropivacaine concentration was 0.030 (0.017-0.071) µg ml-1 (mean [99% confidence interval]) vs 0.095 (0.047-0.208) µg ml-1, and peak total ropivacaine concentration was 0.756 (0.065-1.222) µg ml-1vs 1.695 (0.077-3.005) µg ml-1 for unilateral and bilateral TKA, respectively. The pharmacokinetics was ascribed a one-compartment model with first-order absorption. The main identified covariates were protein binding, allometrically scaled body weight on clearance and volume, and unilateral or bilateral surgery on volume. CONCLUSIONS: This is the first study to investigate the pharmacokinetics of free and total ropivacaine after unilateral and bilateral TKA. A population model was successfully built and peak free ropivacaine concentration stayed below previously proposed toxic thresholds in patients undergoing unilateral and bilateral TKA receiving LIA with high-dose ropivacaine. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04702282.

Are functional outcomes and early pain affected by discharge on the day of surgery following total hip and knee arthroplasty?

Background and purpose - Outpatient total knee and total hip arthroplasty (TKA and THA) has been shown to be feasible and safe in selected patients. However, little data is available on functional outcome and early pain in patients discharged on the day of surgery (DOS). We investigated patient-reported outcomes at 1 year and early pain in outpatient TKA and THA patients discharged on the day of surgery (DOS) (DDOS) compared with patients scheduled for outpatient surgery but not discharged on the DOS (nDDOS).Patients and methods - Prospective data on 261 consecutive patients scheduled for outpatient TKA (n = 126) and THA (n = 135) were collected. 37% of TKA patients and 33% of THA patients were discharged on the DOS. Pain scores at rest and activity and use of morphine were registered on postoperative days 1-7. Oxford Knee Score (OKS) and Oxford Hip Score (OHS) were collected preoperatively and at 3 and 12 months' follow-up.Results - DDOS and nDDOS patients were similar in respect to age, sex, procedure type (TKA vs. THA), or preoperative OKS or OHS. Neither OKS nor OHS differed between groups at 3 and 12 months' follow-up. Pain at rest and activity and use of morphine did not differ between the 2 groups on days 1-7.Interpretation - In patients scheduled for outpatient TKA and THA, we found similar patient-reported outcomes both early and at 1 year in those discharged on the DOS and those who had at least 1 overnight stay.

Early clinical outcome and learning curve following unilateral primary total knee arthroplasty after introduction of a novel total knee arthroplasty system.

BACKGROUND: New implants for total knee arthroplasty (TKA) are continuously introduced with the proposed benefit of increased performance and improved outcome. Little information exists on how the introduction of a novel arthroplasty implant affects the perioperative and surgical outcome immediately after implementation. AIM: To investigate how surgery-related factors and implant positioning were affected by the introduction of a novel TKA system. METHODS: A novel TKA system was introduced at our institution on 30th November 2015. Seventy-five TKAs performed with the Persona TKA immediately following its introduction by 3 different surgeons (25 TKAs/surgeon) were identified as the Introduction Group. Moreover, the latest 25 TKAs performed by each surgeon prior to introduction of the Persona TKA were identified as the Control Group. A Follow-up Group of 25 TKAs/surgeon was identified starting 1-year after the end of the introduction period. Demographics, surgery-related factors and alignment data were recorded, and intergroup differences compared. RESULTS: Following introduction of the novel implant, Persona TKA was utilized in 69% (71%), 53% (54%), and 45% (75%) of primary TKA procedures by the three surgeons, respectively (Follow-up Group). Mean surgery time was increased by 28% (P < 0.0001) and mean intra-operative blood loss by 25% (P = 0.002) in the Introduction Group, while only the mean surgery time was increased in the Follow-up Group by 18% (P < 0.0001). Overall alignment was similar between the groups apart from femoral flexion (FF) and tibial slope (TS). The number of FF outliers was reduced in the Introduction Group with a more pronounced decrease in the Follow-up Group. CONCLUSION: Introduction of the new TKA implant increased surgical time and intraoperative blood loss immediately after its introduction. These differences diminished one year after introduction of the new implant. Fewer outliers with respect to FF and TS were seen when using the novel TKA implant. Further studies are needed to investigate if these differences persist over time and correlate with patient reported outcomes.

Introduction of a New Treatment Algorithm Reduces the Number of Periprosthetic Femoral Fractures After Primary Total Hip Arthroplasty in Elderly Females.

BACKGROUND: Increasing global usage of cementless prostheses in total hip arthroplasty (THA) presents a challenge, especially for elderly patients. To reduce the risk of early periprosthetic femoral fractures (PFFs), a new treatment algorithm for females older than 60 years undergoing primary THA was introduced. The aim of this study was to determine the impact of the new treatment algorithm on the early risk of perioperative and postoperative PFFs and guideline compliance. METHODS: A total of 2405 consecutive THAs that underwent primary unilateral THA at our institution were retrospectively identified in the period January 1, 2013-December 31, 2018. A new treatment algorithm was introduced on April 1, 2017 with female patients aged older than 60 years intended to receive cemented femoral components. Before this, all patients were scheduled to receive cementless femoral components. Demographic data, number of perioperative and postoperative PFFs, and surgical compliance were recorded, analyzed, and intergroup differences compared. RESULTS: The utilization of cemented components in female patients older than 60 years increased from 12.3% (n = 102) to 82.5% (n = 264). In females older than 60 years, a significant reduction in the risk in early postoperative and intraoperative PFF after introduction of the new treatment algorithm was seen (4.57% vs 1.25%; P = .007 and 2.29% vs 0.31%; P = .02, respectively). Overall risk for postoperative and intraoperative fractures combined was also reduced in the entire cohort (4.1% vs 2.0%; P = .01). CONCLUSION: Use of cemented fixation of the femoral component in female patients older than 60 years significantly reduces the number of PFFs. Our findings support use of cemented femoral fixation in elderly female patients.

Preoperative high-dose Steroids in Total Knee and Hip Arthroplasty - Protocols for three randomized controlled trials.

BACKGROUND: Patients undergoing total knee arthroplasty (TKA)/ total hip arthroplasty (THA) still experience moderate-severe postoperative pain despite optimized pain management regimes. The patients already on opioid treatment and pain catastrophizers (PCs) have a higher risk of postoperative pain. The use of preoperative intravenous high-dose glucocorticoids decreases postoperative pain after TKA and THA, but optimal dose is yet to be found, and the effect on subpopulations at high pain risk is unknown. AIM: To investigate the effect of a higher than previously used dose of glucocorticoids (dexamethasone (DXM)), administered intravenously before surgery, as part of standardized fast-track regimen, on postoperative pain in TKA/THA subgroups. METHOD: Three separate randomized, double-blinded, controlled trials were planned to compare a new higher dose DXM (1 mg/kg) to the earlier used high-dose DXM (0.3 mg/kg). Study 1: predicted Low Pain TKA; study 2: predicted High Pain Responder (HPR) TKA; study 3: predicted HPR THA. Predicted HPR groups consist of either PCs with PCS-score of ≥ 21 and/or history of ongoing opioid-treatment of 30 mg/day of morphine or equivalents > 30 days. In total, 408 patients were planned for inclusion (160 Low Pain TKA, 88 HPR TKA, 160 HPR THA). PRIMARY OUTCOME: Pain upon ambulation in a 5-meter walk test 24 hours after surgery. Secondary outcomes include use of analgesics, rescue-opioids, antiemetics, cumulated pain, CRP, OR-SDS, QoR-15, quality of sleep, length of stay (LOS), reasons for hospitalization, readmission, morbidity, and mortality. Patients completed follow-up on day 90. Recruiting commenced February 2019 and is expected to finish in September 2020.

Why are patients still in hospital after fast-track, unilateral unicompartmental knee arthroplasty.

Background and purpose - Previous studies have investigated risk factors related to prolonged length of stay following total knee arthroplasty (TKA), but little is known about specific factors resulting in continued hospitalization within the 1st postoperative days after unicompartmental knee arthroplasty (UKA). We investigated what specific factors prevent patients from being discharged on the day of surgery (DOS) and the first postoperative day (POD-1) following primary UKA in a fast-track setting.Patients and methods - We prospectively collected data on 100 consecutive and unselected medial UKA patients operated from December 2017 to May 2019. All patients were operated in a standardized fast-track setup with functional discharge criteria continuously evaluated from DOS and until discharge.Results - Median length of stay for the entire cohort was 1 day. 22% and 78% of all patients were discharged on DOS and POD-1, respectively. Lack of mobilization and pain separately delayed discharge in respectively 78% and 24% of patients on DOS. The main reasons for lack of mobilization were motor blockade (37%) and logistical factors (26%). For patients placed 1st or 2nd on the operating list, we estimate that the same-day discharge rate would increase to 55% and 40% respectively, assuming that pain and mobilization were successfully managed.Interpretation - One-fifth of unselected UKA patients operated in a standardized fast-track setup were discharged on DOS. Pain and lack of mobilization were the major reasons for continued hospitalization within the initial postoperative 24-48 hours. Strategies aimed at decreasing length of stay after UKA should strive to improve analgesia and postoperative mobilization.

Are There Differences in Micromotion on Radiostereometric Analysis Between Bicruciate and Cruciate-retaining Designs in TKA? A Randomized Controlled Trial.

BACKGROUND: Bicruciate-retaining TKA has been proposed to improve clinical outcomes by maintaining intrinsic ACL function. However, because the unique design of the bicruciate-retaining tibial component precludes a tibial stem, fixation may be compromised. A radiostereometric analysis permits an evaluation of early migration of tibial components in this setting, but to our knowledge, no such analysis has been performed. QUESTIONS/PURPOSES: We performed a randomized controlled trial using a radiostereometric analysis and asked, at 2 years: (1) Is there a difference in tibial implant migration between the bicruciate-retaining and cruciate-retaining TKA designs? In a secondary analysis, we asked: (2) Is there a difference in patient-reported outcomes (Oxford Knee Score [OKS] and Forgotten Joint Score [FJS] between the bicruciate-retaining and cruciate-retaining TKA designs? (3) What is the frequency of reoperations and revisions for the bicruciate-retaining and cruciate-retaining TKA designs? METHODS: This parallel-group trial (ClinicalTrials.gov: NCT01966848) randomized 50 patients with an intact ACL who were eligible to undergo TKA to receive either a bicruciate-retaining or cruciate-retaining TKA. Patients were blinded to treatment allocation. The primary outcome was the maximum total point motion (MTPM) of the tibial component measured with model-based radiostereometric analysis (RSA) at 2 years postoperatively. The MTPM is a translation vector defined as the point in the RSA model that has the greatest combined translation in x-, y- and z-directions. A 1-year postoperative mean MTPM value of 1.6 mm has been suggested as a threshold for unacceptable increased risk of aseptic loosening after both 5 and 10 years. The repeatability of the MTPM was found to be 0.26 mm in our study. Patient-reported outcome measures were assessed preoperatively and at 2 years postoperatively with the OKS (scale of 0-48, worst-best) and FJS (scale of 0-100, worst-best). Baseline characteristics did not differ between groups. At 2 years postoperatively, RSA images were available for 22 patients who underwent bicruciate-retaining and 23 patients who underwent cruciate-retaining TKA, while patient-reported outcome measures were available for 24 patients in each group. The study was powered to detect a 0.2-mm difference in MTPM between groups (SD = 0.2, significance level = 5%, power = 80%). RESULTS: With the numbers available, we found no difference in MTPM between the bicruciate-retaining and cruciate-retaining groups. The median (interquartile range [IQR]) MTPM was 0.52 mm (0.35 to 1.02) and 0.42 mm (0.34 to 0.70) in the bicruciate-retaining and cruciate-retaining groups, respectively (p = 0.63). There was no difference in the magnitude of improvement in the OKS from preoperatively to 2 years postoperative between the groups (median delta [IQR] for bicruciate-retaining 18 [14 to 23] versus cruciate-retaining 18 [15 to 21], difference of medians 0; p = 0.96). Likewise, there was no difference in the magnitude of improvement in the FJS score from preoperatively to 2 years postoperative between the groups (mean ± SD for bicruciate-retaining 46 ± 32 versus cruciate-retaining 48 ± 16, mean difference, 2; p = 0.80). Three patients in the bicruciate-retaining group underwent arthroscopically assisted manipulation at 3 to 4 months postoperatively, and one patient in the bicruciate-retaining group sustained a tibial island fracture during primary surgery and underwent a revision procedure after 6 months. There were no reoperations or revisions in the cruciate-retaining group. CONCLUSIONS: With the numbers available, we found no differences between the bicruciate-retaining and the cruciate-retaining implants in terms of stable fixation on RSA or patient-reported outcome measure scores at 2 years, and must therefore recommend against the routine clinical use of the bicruciate-retaining device. The complications we observed with the bicruciate-retaining device suggest it has an associated learning curve and the associated risks of novelty with no demonstrable benefit to the patient; it is also likely to be more expensive in most centers. Continued research on this implant should only be performed in the context of controlled trials. LEVEL OF EVIDENCE: Level II, therapeutic study.

Patients with anteromedial osteoarthritis achieve the greatest improvement in patient reported outcome after total knee arthroplasty.

The osteoarthritic (OA) disease pattern of the knee is one of the determinants for choice of arthroplasty concept when knee replacement is indicated, but whether the disease pattern has a direct effect on postoperative outcome has not previously been investigated. The aim was to investigate if different OA disease patterns have an effect on postoperative outcome after receiving total knee arthroplasty (TKA). MATERIALS AND METHODS: 472 patients with pre- and 1-year postoperative patient reported outcome measures (PROMs) undergoing TKA surgery were retrospectively identified and classification of the OA disease pattern was made on preoperative radiographs. Measured resection was the universal technical approach. RESULTS: The key findings showed greater improvement in mean PROMs for anteromedial OA (AMOA) compared with other OA disease patterns; 3.1 points (95% CI 1.4-4.7, p < 0.001) in Oxford Knee score, 11.7 points (95% CI 0.9-22.5, p = 0.034) in Forgotten Joint score and 0.08 points (95% CI 0.02-0.14, p = 0.007) in EQ 5D score. Similar results were observed when comparing AMOA with AMOA that had only partial thickness cartilage loss (AMOA-PTCL). CONCLUSIONS: Patients with AMOA achieve greater improvement in PROMs after TKA surgery when using measured resection compared with other OA disease patterns. This finding has important implications for reporting, risk stratification and interpretation in TKA outcome studies, including randomized trials, why further investigation of the topic is of highly relevance.

[Total knee and hip arthroplasty within 2 days : The Danish Fast-Track Model]. / Knie- und Hüfttotalendoprothese in 2 Tagen : Das dänische Fast-Track-Modell.

BACKGROUND: Patients in Denmark undergoing total knee or hip replacement are routinely discharged within 2 days of surgery. A critical examination of traditional treatment methods, combined with focused research, has during the last 20 years increasingly optimized the treatment course in such a way that it has become possible to radically reduce the length of stay (LOS). BASICS OF THE FAST-TRACK MODEL: The most important elements of this Fast-Track model are described. The patient motivation and transfer of partial responsibility to the patient through intensive information, optimized operation techniques, as well as modern multi-modal pain therapy with early mobilization are key issues. The relatively small and homogenous health care system of Denmark offers good research conditions and the possibility of a fast implementation of the latest results, as well as a lump-sum based re-imbursement system without minimum stay-both factors have been favorable for the development of the Fast-Track model.

Outpatient total hip or knee arthroplasty in ambulatory surgery center versus arthroplasty ward: a randomized controlled trial.

Background and purpose - Discharge on the day of surgery (DOS) in selected patients operated with total hip arthroplasty (THA) or total knee arthroplasty (TKA) has been shown to be feasible, but different factors may determine whether patients are discharged on the DOS or not and setting may be one of them. We investigated the importance of the setting in which the short stay following outpatient THA or TKA takes place: was there a difference between the proportion of patients being discharged on the DOS from an ambulatory surgery center (ASC) compared with patients staying on an arthroplasty ward?Patients and methods - 50 patients (30 TKA, 20 THA) were included in the study and postoperatively randomized to either staying in the ASC or the arthroplasty ward until discharge. All patients were operated under general anesthesia by the same experienced surgeon (HH) and were discharged upon fulfillment of standardized discharge criteria.Results - 24/25 of the patients who stayed in the ASC compared with 20/25 of the patients on the arthroplasty ward were discharged on the DOS following fulfillment of discharge criteria (p = 0.08). All THA patients were discharged on the DOS and significantly more TKA patients were discharged from the ASC (15/16) vs. from the ward (9/14) (p = 0.04).Interpretation - Despite fixed discharge criteria, the logistical setting may play a role for achieving discharge on DOS and the ASC may facilitate achieving discharge criteria earlier especially in TKA.

Quadriceps muscle activity during commonly used strength training exercises shortly after total knee arthroplasty: implications for home-based exercise-selection.

BACKGROUND: In the early phase after a total knee arthroplasty (TKA), patients experience multi-level weakness in the operated leg, which is caused primarily by reduced central nervous system (CNS) activation failure of the muscles - especially the knee extensors (quadriceps muscle). Whether similar levels of neuromuscular activity of the muscles in the operated leg, elicited during strength training exercises in machines, can be reached during strength training exercises in more simple forms is unknown. Many clinicians are faced with the problem of not having strength training equipment at their institution or having to prescribe simple strength training exercises for home-based training. Therefore, the purpose of this study was to determine which strength training exercises that activated the muscles in the operated leg the most after TKA. The hypothesis was that strength training exercises performed in machines would elicit higher levels of voluntary peak quadriceps and hamstring muscle activity than strength training exercises performed in more simple forms, using elastic bands or the patients' own body weight. METHODS: A cross-sectional electromyographic study investigated voluntary peak muscle activity in the operated leg during 6 different strength training exercises. Twenty-four patients, who received a TKA 4 to 8 weeks earlier, performed the exercises in a randomized order, using a pre-determined loading of 10 RM (repetition maximum). Voluntary peak muscle activity (%EMGmax) was calculated for the quadriceps and hamstring muscles for each exercise. RESULTS: Knee extensions with elastic band showed significantly higher voluntary peak quadriceps muscle activity than knee extensions in machine (93.3 vs. 74.9; mean difference, 18.3 %EMGmax [95% confidence interval (CI), 11.7 to 24.9]; P < 0.0001). Similarly, one-legged squat (and sit to stand) elicited higher voluntary peak quadriceps muscle activity than leg press in machine (86.7 vs. 66.8; mean difference, 19.9 %EMGmax [95% CI, 14.8 to 25.0]; P < 0.0001). CONCLUSIONS: Strength training exercises in more simple forms elicited higher voluntary peak quadriceps muscle activity than strength training exercises in machines early after TKA. Consequently, simple home-based strength training exercises using e.g. elastic bands or the patients' own bodyweight should be considered to alleviate muscle strength losses early after TKA. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01708980 .

Tissue Adhesive for Wound Closure Reduces Immediate Postoperative Wound Dressing Changes After Primary TKA: A Randomized Controlled Study in Simultaneous Bilateral TKA.

BACKGROUND: Prolonged wound drainage after TKA is associated with increased risk of infection. To decrease wound drainage, tissue adhesive has been suggested as an adjunct to wound closure after TKA; however, no studies of which we are aware have investigated the effect of tissue adhesive in a modern fast-track TKA setting. QUESTIONS/PURPOSES: The purpose of this study was to evaluate the effect of wound closure using a high-viscosity tissue adhesive in simultaneous bilateral TKA with respect to (1) postoperative wound drainage, measured as number of dressing changes in the first 72 hours postoperatively; and (2) wound healing assessed using the ASEPSIS score. METHODS: Thirty patients undergoing simultaneous bilateral TKA were included in the study. The left knee was randomized to receive either standard three-layer closure with staples or the same closure supplemented with tissue adhesive with the opposite treatment used on the contralateral knee. One patient underwent a constrained TKA and underwent revision 2 days after the index procedure and was therefore excluded leaving 29 patients (58 knees) for analysis. Sixty-two percent (n = 18) were female. Mean age was 64 years (range, 42-78 years). Mean body mass index was 28 kg/m (range, 21-38 kg/m). Postoperative wound drainage was evaluated as drainage resulting in a dressing change. The wound dressing was changed if it was soaked to the borders of the absorbable dressing at any point. The nurses changing the dressing were blinded to treatment allocation up to the first dressing change. The number of dressing changes during the first 72 hours postoperatively was recorded. The secondary study endpoint was the ASEPSIS score, which is a clinical score assessing wound healing. ASEPSIS score, measured by a nurse not involved in the treatment, was compared between the groups at 3 weeks followup. RESULTS: Knees with tissue adhesive underwent fewer dressing changes (median, 0; interquartile range [IQR], 0-1) compared with the contralateral knee (IQR, 1-2; difference of medians, one dressing change; p = 0.001). A total of 59% of knees in the intervention group did not undergo any dressing changes before discharge, whereas 24% of knees in the control group did not undergo any dressing changes before discharge (p = 0.02). The knees in the intervention group and the control group did not differ with respect to ASEPSIS score at 3 weeks. CONCLUSIONS: Tissue adhesive as an adjunct to standard wound closure after primary TKA reduced the number of dressing changes after surgery, but did not change the appearance or healing of the wound at 3 weeks based on the ASEPSIS scores. Whether the small differences observed here in terms of the number of dressing changes performed will justify the additional costs associated with using this product or whether there are other differences associated with the use of tissue adhesive that may prove important such as patient preferences or longer term differences in wound healing or infection should be studied in the future. LEVEL OF EVIDENCE: Level I, therapeutic study.

Varying but reduced use of postoperative mobilization restrictions after primary total hip arthroplasty in Nordic countries: a questionnaire-based study.

Background and purpose - Mobilization has traditionally been restricted following total hip arthroplasty (THA) in an attempt to reduce the risk of dislocation and muscle detachment. However, recent studies have questioned the effect and rationale underlying such restrictions. We investigated the use of postoperative restrictions and possible differences in mobilization protocols following primary THA in Denmark (DK), Finland (FIN), Norway (NO), and Sweden (SWE). Patients and methods - All hospitals performing primary THA in the participating countries were identified from the latest national THA registry report. A questionnaire containing questions regarding standard surgical procedure, use of restrictions, and postoperative mobilization protocol was distributed to all hospitals through national representatives for each arthroplasty registry. Results - 83% to 94% (n = 167) of the 199 hospitals performing THA in DK, FIN, NO, and SWE returned correctly filled out questionnaires. A posterolateral approach was used by 77% of the hospitals. 92% of the hospitals had a standardized mobilization protocol. 50%, 41%, 19%, and 38% of the hospitals in DK, FIN, NO, and SWE, respectively, did not have any postoperative restrictions. If utilized, restrictions were applied for a median of 6 weeks. Two-thirds of all hospitals have changed their mobilization protocol within the last 5 years-all but 2 to a less restrictive protocol. Interpretation - Use of postoperative restrictions following primary THA differs between the Nordic countries, with 19% to 50% allowing mobilization without any restrictions. There has been a strong tendency towards less restrictive mobilization over the last 5 years.

Complications and readmissions following outpatient total hip and knee arthroplasty: a prospective 2-center study with matched controls.

Background and purpose - Outpatient arthroplasty has gained popularity in recent years; however, safety concerns still remain regarding complications and readmissions. In a prospective 2-center study we investigated early readmissions with overnight stay and complications following outpatient total hip (THA) and total knee arthroplasty (TKA) compared with a matched patient cohort with at least 1 postoperative night in hospital. Patients and methods - All consecutive and unselected patients scheduled for THA or TKA at 2 participating hospitals were screened for potential day of surgery (DOS) discharge. Patients who fulfilled the DOS discharge criteria were discharged home. Patients discharged on DOS were matched on preoperative characteristics using propensity scores to patients operated at the same 2 departments prior to the beginning of this study with at least 1 overnight stay. All readmissions within 90 days were identified. Results - It was possible to match 116 of 138 outpatients with 339 inpatient controls. Median LOS in the control cohort was 2 days (1-9). 7 (6%) outpatients and 13 (4%) inpatient controls were readmitted within 90 days. Readmissions occurred between postoperative day 2-48 and day 4-58 in the outpatient and control cohorts, respectively. Importantly, we found no readmissions within the first 48 hours and no readmissions were related to the DOS discharge. Interpretation - Readmission rates in patients discharged on DOS may be similar to matched patients with at least 1 overnight stay. With the selection criteria used, there may be no safety signal associated with same-day discharge.

Sensitivity and specificity of post-operative interference gap assessment on plain radiographs after cementless primary THA.

INTRODUCTION: Implant performance of cementless THA is often evaluated by radiolucency on plain radiographs, often classified as interference gaps on direct post-operative radiographs. However, the diagnostic performance is unknown. The aim was to evaluate the diagnostic performance of radiographic assessment of post-operative gaps after primary THA by comparing it with CT confirmed gaps, and secondary to define optimal cut-off criteria for assessing gaps on plain radiographs compared with CT. MATERIAL AND METHODS: Patients (N = 40) with a primary cementless THA performed between July 2015 and March 2016 were enrolled in the study. Radiolucency was assessed on post-operative AP pelvic digital radiographs by two observers independently. Maximum width and percentage of coverage per zone were reported. Gap volume was measured by manual segmentation on CT images. RESULTS: When defining a gap as a radiolucency extending through >50% of a zone, the interrater agreement Kappa was 0.241. Sensitivity was 65.8% for observer 1 (Kappa = 0.432), and 86.8% for observer 2 (Kappa = 0.383). When defining a gap as a radiolucency with a width >1 mm, the interrater agreement Kappa was 0.302. Sensitivity was 55.3% and 50% for observer 1 and observer 2, respectively. The ROC-curve resulted in an optimal threshold of 0.65 mm (AUROC = 0.888) and 0.31 mm (AUROC = 0.961) for the two observers. CONCLUSION: The diagnostic performance of observers detecting interference gaps on radiographs showed low sensitivity. Further on, the inter-rater agreement is too low to do a general recommendation about thresholds for defining gaps. Evaluating progression of radiolucency on radiographs should be performed in the light of these findings.