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The article presents a college thesis which investigated the determinants of the outcomes of lumbar spinal stenosis surgery and is based on several papers previously published by F. G. Sigmundsson, B. Jönsson and B.Strömqvist, including papers which appeared in a 2013 issue of "Acta Orthopaedica", a 2012 issue of "Acta Orthopaedica" and a 2014 issue of "Spine".

Background and purpose — The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA, have been sparsely described. The Nordic Arthroplasty Register Association (NARA) has already published 2 papers describing results of reverse hybrid THAs in different age groups. Based on data collected over 2 additional years, we wanted to perform in depth analyses of not only the reverse hybrid concept but also of the different cup/stem combinations used. Patients and methods — From the NARA, we extracted data on reverse hybrid THAs from January 1, 2000 until December 31, 2013. 38,415 such hips were studied and compared with cemented THAs. The Kaplan-Meier method and Cox regression analyses were used to estimate the prosthesis survival and the relative risk of revision. The main endpoint was revision for any reason. We also performed specific analyses regarding the different reasons for revision and analyses regarding the cup/stem combinations used in more than 500 cases. Results — We found a higher rate of revision for reverse hybrids than for cemented THAs, with an adjusted relative risk of revision (RR) of 1.4 (95% CI: 1.3–1.5). At 10 years, the survival rate was 94% (CI: 94–95) for cemented THAs and 92% (95% CI: 92–93) for reverse hybrids. The results for the reverse hybrid THAs were inferior to those for cemented THAs in patients aged 55 years or more (RR =1.1, CI: 1.0–1.3; p < 0.05). We found a higher rate of early revision due to periprosthetic femoral fracture for reverse hybrids than for cemented THAs in patients aged 55 years or more (RR =3.1, CI: 2.2–4.5; p < 0.001). Interpretation — Reverse hybrid THAs had a slightly higher rate of revision than cemented THAs in patients aged 55 or more. The difference in survival was mainly caused by a higher incidence of early revision due to periprosthetic femoral fracture in the reversed hybrid THAs. [ABSTRACT FROM PUBLISHER]

Background and purpose — Custom triflange acetabular components (CTACs) are suggested as good solutions for large acetabular defects in revision total hip arthroplasty. However, high complication rates have been reported and most studies are of limited quality. This prospective study evaluates the performance of a CTAC in patients with large acetabular defects including pelvic discontinuity. Patients and methods — Prospectively collected data of 49 consecutive patients (50 hips), who underwent an acetabular revision with a CTAC were analyzed. Follow-up (FU) was 2 years. The median age of the patients was 68 years (41–89) and 41 were women. Primary outcomes were re-revision of the CTAC and differences between the modified Oxford Hip Score (mOHS) preoperatively and at 2-year follow-up. Secondary outcomes included several patient-reported outcomes (PROMs), radiological results, complications, and a comparison between hips with and without pelvic discontinuity (PD). Results — 1 patient (1 hip) was lost to the 2-year FU. No CTAC needed re-revision. The preoperative and 2-year FU mOHS were available in 40 hips and improved statistically significantly. All of the other secondary outcomes improved over time. 5 hips (of 45 with radiological 2-year FU) had loosening of screws. 8 hips had complications, including 3 persistent wound leakage, 3 pelvic fractures, and 1 dislocation. The mOHS and complication rate were similar in hips with and without PD. Interpretation — Reconstruction of large acetabular defects with and without PD with this CTAC showed good improvement in patient-reported daily functioning, high patient-reported satisfaction, few complications, and no re-revisions at 2-year FU. [ABSTRACT FROM AUTHOR]

Background and purpose — There is ongoing debate as to whether commercial funding influences reporting of medical studies. We asked: Is there a difference in reported tones between abstracts, introductions, and discussions of orthopedic journal studies that were commercially funded and those that were not commercially funded? Methods — We conducted a systematic PubMed search to identify commercially funded studies published in 20 orthopedic journals between January 1, 2000 and December 1, 2019. We identified commercial funding of studies by including in our search the names of 10 medical device companies with the largest revenue in 2019. Commercial funding was designated when either the study or 1 or more of the authors received funding from a medical device company directly related to the content of the study. We matched 138 commercially funded articles 1 to 1 with 138 non-commercially funded articles with the same study design, published in the same journal, within a time range of 5 years. The IBM Watson Tone Analyzer was used to determine emotional tones (anger, fear, joy, and sadness) and language style (analytical, confident, and tentative). Results — For abstract and introduction sections, we found no differences in reported tones between commercially funded and non-commercially funded studies. Fear tones (non-commercially funded studies 5.1%, commercially funded studies 0.7%, p = 0.04), and analytical tones (non-commercially funded studies 95%, commercially funded studies 88%, p = 0.03) were more common in discussions of studies that were not commercially funded. Interpretation — Commercially funded studies have comparable tones to non-commercially funded studies in the abstract and introduction. In contrast, the discussion of non-commercially funded studies demonstrated more fear and analytical tones, suggesting them to be more tentative, accepting of uncertainty, and dispassionate. As text analysis tools become more sophisticated and mainstream, it might help to discern commercial bias in scientific reports. [ABSTRACT FROM AUTHOR]

The article discusses a study aimed at testing the accuracy and precision of radiostereometric analysis (RSA) as applied to sacroiliac joint (SIJ) in a phantom model and in patients. Topics discussed include SIJ as a possible source of pain for 13-30% of patients with low back pain (LBP), the common characteristics in the clinical presentation of patients with pelvic girdle pain (PGP) including the location of the pain and surgery as an appropriate treatment option for patients with severe PGP.

The article discusses diseases, including osteoarthritis, lunate malacia and inflammatory arthritis, for which total wrist arthroplasty is used and discusses the different types of wrist arthroplasty, including Volz wrist arthroplasty, the meuli wrist arthroplasty system and trispherical wrist arthroplasty, which are available to orthopaedic professionals. A discussion of research which investigated several papers concerned with wrist arthroplasty, including "Promising 1-6 Years Results With the Motec Wrist Arthroplasty in SN AC and SL AC patients" by O. Reigstad, T.Lütken, C. Grimsgaard et al., "New Concept for Total Wrist Replacement" by A. Reigstad, O. Reigstad, C. Grimsgaard et al. and "Improved Bone Ingrowth and Fixation With a Thin Calcium Phosphate Coating Intended for Complete Resorption" by O. Reigstad, V. Franke-Stenport, C. Johansson et al, is presented.

Background Numerous papers have been published on the medium- and long-term results of hemiarthroplasties (HAs) after femoral neck fracture in the elderly. We were not aware of any articles that describe the outcome of HA until the patient dies. Methods Between 1975 and 1989, 307 bipolar hemiarthroplasties were performed in 302 consecutive patients with a displaced femoral neck facture. Patients with osteoarthritis of the hip, rheumatoid arthritis (RA), or senile dementia were not included in the study. All patients were followed annually until they died or until they needed a revision operation. Results The mortality rate was 28% after 1 year, and 63% after 5 years. The last patient who did not need a revision operation died in October 2010. Revision operations for aseptic loosening, protrusion, or both had to be performed in 34 patients (16%). A difference in reoperation rate was observed between patients less than 75 years of age (38%) and those who were older (6%). Interpretation Apart from age below 75 years, male sex appeared to be predictive of a revision operation. HA is a safe and relatively inexpensive treatment for patients over 75 years of age with a displaced femoral neck fracture. [ABSTRACT FROM AUTHOR]

Background and purpose The properties and performance of a new low-monomer cement were examined in this prospective randomized, controlled RSA study. 5-year data have already been published, showing no statistically significant differences compared to controls. In the present paper we present the 10-year results. Methods 44 patients were originally randomized to receive total hip replacement with a Lubinus SPII titanium-aluminum-vanadium stem cemented either with the new Cemex Rx bone cement or with control bone cement, Palacos R. Patients were examined using RSA, Harris hip score, and conventional radiographs. Results At 10 years, 33 hips could be evaluated clinically and 30 hips could be evaluated with RSA (16 Cemex and 14 Palacos). 9 patients had died and 4 patients were too old or infirm to be investigated. Except for 1 hip that was revised for infection after less than 5 years, no further hips were revised before the 10-year follow-up. There were no statistically significant clinical differences between the groups. The Cemex cement had magnitudes of migration similar to or sometimes lower than those of Palacos cement. In both groups, most hips showed extensive radiolucent lines, probably due to the use of titanium alloy stems. Interpretation At 10 years, the Cemex bone cement tested performed just as well as the control (Palacos bone cement). [ABSTRACT FROM AUTHOR]

Background and purpose In January 2008, we established the Norwegian Register for Shoulder Instability Surgery. We report on the establishment, the baseline data, and the results at 1-year follow-up. Methods Primary and revision shoulder stabilization is reported by the surgeon on a 1-page paper form containing the patient's history of shoulder injury, clinical findings, and perioperative findings. The WOSI questionnaire for self-assessment of shoulder function is completed at baseline and at follow-up after 1, 2, and 5 years. To evaluate the completeness of registration, we compared our data with those in the Norwegian Patient Registry (NPR). Results The NPR reported 39 hospitals performing shoulder stabilizations. 20 of these started to report to our register during 2009, and 464 procedures (404 primary, 59 revisions) were included up to December 31, 2009, which represented 54% of the procedures reported to NPR. Of the 404 primary procedures, 83% were operations due to anterior instability, 10% were operations due to posterior instability, and 7% were operations due to multidirectional instability. Arthroscopic soft tissue techniques were used in 88% of the patients treated for primary anterior instability and open coracoid transfer was used in 10% of such patients. At 1-year follow-up of 213 patients, we found a statistically significantly improved WOSI score in all types of instability. 10% of the patients treated with arthroscopic anterior labral repair and 16% treated with arthroscopic posterior labral repair reported recurrent instability. No statistically significant difference in functional improvement or rate of recurrence was found between these groups. Interpretation The functional results are in accordance with those in previous studies. However, the incidence of recurrent instability 1 year after arthroscopic labral repair is higher than expected. [ABSTRACT FROM AUTHOR]

Background and purpose -- Robotic-assisted total knee arthroplasty (RATKA) is an alternative surgical treatment method to conventional total knee arthroplasty (COTKA) that may deliver better surgical accuracy. However, its impact on patient outcomes is uncertain. The aim of this systematic review of randomized controlled trials (RCTs) is to evaluate whether RATKA could improve functional and radiological outcomes compared with COTKA in adult patients with primary osteoarthritis of the knee. Methods -- We searched Ovid MEDLINE, EMBASE, Scopus, and the Cochrane Library to identify published RCTs comparing RATKA with COTKA. 2 reviewers independently screened eligible studies, reviewed the full texts, assessed risk of bias using the Risk of Bias 2.0 tool, and extracted data. Outcomes were patient-reported outcomes, range of motion, and mechanical alignment (MA) deviation and outliers, and complications. Results -- We included 12 RCTs involving 2,200 patients. RATKA probably results in little to no effect on patient-reported outcomes (mean difference (MD) in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score of -0.35 (95% confidence interval [CI] -0.78 to 0.07) and range of motion (MD -0.73°; CI -7.5° to 6.0°) compared with COTKA. However, RATKA likely results in a lower degree of MA outliers (risk ratio 0.43; CI 0.27 to 0.67) and less deviation from neutral MA (MD -0.94°; CI -1.1° to -0.73°). There were no differences in revision rate or major adverse effects associated with RATKA. Conclusion -- Although RATKA likely results in higher radiologic accuracy than COTKA, this may not be clinically meaningful. Also, there is probably no clinically important difference in clinical outcomes between RATKA and COTKA, while it is as yet inconclusive regarding the revision and complication rates due to insufficient evidence. [ABSTRACT FROM AUTHOR]

Background and purpose -- We conducted a systematic review and meta-analysis of RSA studies to investigate the early and long-term migration patterns of acetabular cups and the influence of implant factors on cup migration over time. Methods -- We performed a systematic search of PubMed, Embase, and Scopus databases to identify all RSA studies of cup migration following primary total hip replacement (THR). Proximal migration at 3 and 6 months, 1, 2, 5, and 10 years were considered for analysis. Implant factors investigated included fixation type, head size, bearing surface, uncemented coating design, and the decade of RSA introduction. Results -- 47 studies reported the proximal migration of 83 cohorts (2,328 cups). Besides 1 threaded cup design, no implant factor investigated was found to significantly influence proximal migration. The mean pooled 2-year proximal migration of cemented cups (0.14 mm, 95% confidence interval [CI] 0.08-0.20) was not significantly different from uncemented cups (0.12 mm, CI 0.04-0.19). The mean pooled proximal migration at 6 months was 0.11 mm (CI 0.06-0.16) and there was no significant increase between 6 months and 2 years (0.015 mm, CI 0.000-0.030). 27 of 75 cohorts (36%) reported mean proximal migration greater than 0.2 mm at 2 years, which has previously been identified as a predictor of implants at risk of long-term loosening. Conclusion -- Our meta-analysis demonstrated that the majority of cup migration occurs within the first 6 months. With one exception, no implant factors influenced the 2-year proximal migration of acetabular cups. 36% of studies with 2-year migration were considered at risk of long-term loosening. Further investigation and comparison against longterm survivorship data would validate 6-month and/or 1-year proximal migration measurements as an earlier predictor of long-term loosening than the current 2-year threshold. [ABSTRACT FROM AUTHOR]

Background and purpose -- We aimed to examine the temporal trends in periprosthetic joint infection (PJI) revision incidence after knee arthroplasty (KA) from 1997 through 2019. Patients and methods -- 115,120 primary KA cases from the Danish Knee Arthroplasty Register were followed until the first PJI revision. We computed cumulative incidences and adjusted hazard ratios (aHRs) of PJI revision by calendar periods and several patient- and surgical-related risk factors. Results were analyzed from 0-3 months and from 3-12 months after KA. Results -- The overall 1-year PJI revision incidence was 0.7%, increasing from 0.5% to 0.7% (1997 through 2019). The incidence of PJI revision within 3 months increased from 0.1% to 0.5% (1997 through 2019). The adjusted hazard ratio (aHR) within 1 year of primary KA was 5.1 comparing 2017-2019 with 2001-2004. The PJI revision incidence from 3-12 months of KA decreased from 0.4% to 0.2%, with an aHR of 0.5 for 2017-2019 vs. 2001-2004. Male sex, age 75-84 (vs. 65-74), and extreme obesity (vs. normal weight) were positively associated with the risk of PJI revision within 3 months, whereas only male sex was associated from 3-12 months. Partial knee arthroplasty (PKA) vs. total KA was associated with a lower risk of PJI revision both within 3 months and 3-12 months of KA. Conclusion -- We observed an increase in PJI revision within 3 months of KA, and a decrease in PJI revision incidence from 3-12 months from 1997 through 2019. The reasons for this observed time-trend are thought to be multifactorial. PKA was associated with a lower risk of PJI revision. [ABSTRACT FROM AUTHOR]

Background and purpose -- We aimed to establish the incidence of late-detected developmental dysplasia of the hip (DDH) with a selective ultrasound (US) examination over 17 years using the femoral head coverage (FHC) as a US measurement. The secondary aim was to establish the everyday function using patient-reported outcome measures (PROMs). Patients and methods -- The incidence of late-detected DDH was based on 60,844 children. Patients diagnosed for the first time after 3 months and before the age of 8 years were included. In the second part of the study, consent to participate was mandatory. PROMIS-25 Pediatric, PROMIS-25 Parent, and EQ-5D-5L were used according to the patient's age to assess everyday function. Results -- The incidence of late-detected DDH was 0.48/1,000. The median age at diagnosis was 8 months (range 4-41 months), with a tendency to require repeated treatment with open surgery if DDH was diagnosed later. Most children reported no or minor health problems with a mean of 18 years' follow-up. Conclusion -- We found that selective US examination of the hips by measuring the FHC is a reliable method to examine newborns for DDH resulting in a low incidence of latedetected DDH amounting to 0.48/1,000 newborn children. [ABSTRACT FROM AUTHOR]

Background and purpose -- Despite usage of the ATTUNE total knee arthroplasty (TKA) for about 10 years, few randomized trials exist. We evaluated whether the ATTUNE CR design showed improved clinical results compared with the PFC Sigma CR after 2 years and if there was a difference in tibial component migration. Patients and methods -- 96 patients with knee osteoarthritis were randomly treated with cemented ATTUNE or PFC Sigma TKA. 42 patients with the ATTUNE and 48 with the PFC Sigma attended the 2-year follow-up. Patient-reported outcome measurements (PROMs), migration measured with RSA, implant position, and the development of radiolucent zones were studied. Non-parametric tests and repeated measures analysis were used at the statistical evaluation. Results -- The Oxford Knee Score (OKS) at 2 years (primary outcome) and neither of the secondary PROM outcomes differed between the groups (mean difference OKS ATTUNE - PFC: -0.08, 95% confidence interval [CI] -2.9 to 2.7). RSA showed posterior tilt of the tibial component in the ATTUNE group with proximal lift-off anteriorly and subsidence of the tibial tray posteriorly. In contrast, the PFC Sigma tibial component tilted forward (mean difference ATTUNE - PFC: -0.7°, CI -1.1° to -0.4°) with maximum subsidence in the front and maximum lift-off of the posterior edge. The postoperative implant positions and the extension of radiolucent lines around the tibial component at 2 years did not differ. Conclusion -- We found no significant differences in clinical outcome between the 2 groups but minor differences in migration pattern of the tibial component. The clinical long-term significance of this finding if any is not known. [ABSTRACT FROM AUTHOR]

Background and purpose -- Radiostereometric analysis (RSA) is the gold standard for evaluation of migration of implants. CT-RSA has been shown to have precision at the level of RSA in hip, shoulder, and knee joint replacements. We aimed to assess the impact of dose reduction on precision of CT-RSA on tibial implants, comparing it with previously published data on precision of standard dose CT-RSA on tibial implants. Material and methods -- We performed a total knee arthroplasty on a porcine knee cadaver, and subsequent CT-RSA with low effective doses (0.02 mSv). We compared the results with previously published CT-RSA data with standard (0.08 mSv) dose. The primary outcome variable was the difference in precision of the maximum total translation (MTT). Secondary variables included ratios of variances and standard deviations, and precision of peripheral point translations, center-of-mass translations, and rotations. A difference of more than 0.1 mm in precision was defined as clinically relevant. Our hypothesis was that precisions of low and standard CT-RSA doses were equal. Results -- Low dose (mean 0.07, 95% confidence interval [CI] 0.06-0.08) and standard dose CT-RSA (0.08, CI 0.07-0.09) achieve similar precision, with difference in precision of MTT of 0.01, CI 0.00-0.02 mm. The F-statistic (0.99, CI 0.63-1.55) and sdtest (1.05, CI 0.43-2.58) also supported this. Conclusion -- We conclude that the precision of low dose CT-RSA for tibial implants on a porcine cadaver is equal to standard dose CT-RSA. However, these findings should be confirmed in clinical trials. [ABSTRACT FROM AUTHOR]

Background and purpose -- The direct superior approach (DSA) is a modification of the posterolateral approach (PLA) for total hip arthroplasty (THA). Patient-reported outcome measures (PROMs) of the DSA have not been investigated previously using nationwide data. Our aim was to assess PROMs after THA using the DSA compared with the PLA and, secondarily, with the anterior approach (DAA). Patients and methods -- In this population-based cohort study we included 37,976 primary THAs performed between 2014 and 2020 (PLA: n = 22,616; DAA: n = 15,017; DSA: n = 343) using Dutch Arthroplasty Registry data. PROMs (NRS pain, EQ-5D, HOOS-PS, and OHS) were measured preoperatively, and at 3 and 12 months postoperatively. Repeated measurements were analyzed using mixed-effects models, adjusted for confounders, to investigate the association between surgical approach and PROMs over time. Results -- From baseline to 3 and 12 months, improvements for NRS pain scores, EQ-5D, and OHS were comparable for the DSA compared with the PLA or DAA. No difference was found in HOOS-PS improvement 3 months postoperatively between DSA and PLA (-0.2, 95% confidence interval [CI] -2.4 to 1.9) and between DSA and DAA (-1.7, CI -3.9 to 0.5). At 12 months postoperatively, patients in the DSA group had improved -2.8 points (CI -4.9 to -0.6) more in HOOS-PS compared with the DAA, but not with the PLA group (-1.0, CI -3.2 to 1.1). Conclusion -- Our study showed no clinically meaningful differences between the DSA and either PLA or DAA. [ABSTRACT FROM AUTHOR]

Background and purpose -- In patients around retirement age controversy exists as to whether to treat displaced femoral neck fracture (dFNF) with internal fixation (IF) or arthroplasty. An arthroplasty in this age group may need revision due to a long expected remaining lifetime. IF carries a higher risk of early failure but a maintained native hip if healing occurs. We aimed to determine the cumulative 5-year rate of conversion to arthroplasty after IF and implant revision after primary total hip arthroplasty (THA), respectively. Patients and methods -- In this longitudinal cohort study, patients aged 60-69 years registered with a dFNF in the Swedish Fracture Register (SFR) 2012-2018 were cross-referenced with available data from the Swedish Arthroplasty Register (SAR) until December 31, 2019. Conversion to arthroplasty or revision were analyzed utilizing competing risk, with death as competing event. Results -- At 5 years, the cumulative rate of conversion to arthroplasty after IF was 31% (95% confidence interval [CI] 26-37). For primary THA, the 5-year rate of revision was 4.0% (CI 2.8-5.8). The 5-year mortality did not differ, being 20% (CI 16-27) and 23% (CI 20-28) after IF and THA, respectively. Regression analyses did not identify any risk factors for conversion arthroplasty based on the variables in the register. Conclusion -- A follow-up of 5 years catches most reoperations after IF, resulting in a 31% conversion rate. The 4% revision rate at 5 years after primary THA should be seen as an intermediate result, as late complications may occur. [ABSTRACT FROM AUTHOR]

Background and purpose -- High-dose dual antibioticloaded bone cement (ALBC) may reduce the risk of revision after total hip and knee replacements. The aim of our study therefore was to determine the risk of re-revision following first time aseptic hip or knee revision using single versus dual ALBC. Patients and methods -- Patients from the Dutch Arthroplasty Register treated from 2007 to 2018 with first time cemented aseptic hip (n = 2,529) or knee revisions = 7,124) were incorporated into 2 datasets. The primary endpoint of this observational cohort study was subsequent all-cause re-revision. Multivariable Cox proportional hazard and competing risk was analyzed for both groups. Results -- There was no difference in re-revision rate (any reason) with single versus dual ALBC (hazard ratio 1.06, 95% confidence interval [CI] 0.83-1.35 for hip and 0.93, CI 0.80-1.07 for knee revisions). The 10-year crude cumulative re-revision rate also showed no differences single versus dual ALBC use. The crude cumulative 7-year THA re-revision and 9-year TKA re-revision rates did show any difference in implant survival for common cement types used. Conclusion -- We could not confirm the potential benefit of using dual ALBC compared with single ALBC for aseptic hip and knee revisions. [ABSTRACT FROM AUTHOR]

Background and purpose -- The Brace Questionnaire (BrQ) is a disease-specific health-related quality of life (HRQOL) instrument for measuring perceived health status of scoliosis patients undergoing brace treatment. The purpose of this study is to evaluate the validity and reliability of a translated and culturally adapted Dutch version of the BrQ. Patients and methods -- The original Greek BrQ was translated into Dutch and a cross-cultural adaptation and validation processes were conducted. Subsequently, 80 adolescent idiopathic scoliosis (AIS) patients undergoing active brace treatment were included from 4 scoliosis centers to evaluate the validity and reliability of the Dutch version of the BrQ. The questionnaire's floor and ceiling effects, internal consistency, and test-retest reliability were assessed. Concurrent validity was evaluated by comparing the BrQ with the revised Scoliosis Research Society 22-item questionnaire (SRS-22r) scores. Results -- The mean total BrQ score was 75.9 (standard deviation [SD] 11.3) and the mean domain scores varied between 3.4 (SD 0.9) and 4.2 (SD 0.7) for the domains "vitality" and "bodily pain," respectively. There were no floor and ceiling effects for the total BrQ score. The BrQ showed satisfactory internal consistency in most subdomains with a Cronbach's α ranging between 0.35 for the domain "general health perception" and 0.89 for the domain "self-esteem and aesthetics." Excellent test-retest reproducibility was observed for the total BrQ score (ICC 0.91), and the BrQ was successfully validated against the SRS-22r. Conclusion -- The translated and culturally adapted Dutch version of the BrQ is a valid and reliable HRQOL instrument for AIS patients undergoing brace treatment. [ABSTRACT FROM AUTHOR]

Background and purpose -- Surgery for bone metastases in the appendicular skeleton (aBM) is a trade-off between limb function and survival. A previous study from a highly specialized center found that extended surgery is not a risk for 30-day mortality and hypothesized that wide resection and reconstruction might reduce postoperative mortality. The study aimed to investigate whether parameters describing the surgical trauma (blood loss, duration of surgery, and degree of bone resection) pose a risk for 30-day mortality in patients treated with endoprostheses (EPR) or internal fixation (IF) in a population-based cohort. Patients and methods -- A population-based cohort having EPR/IF for aBM in the Capital Region of Denmark 2014-2019 was retrospectively assessed. Intraoperative variables and patient demographics were evaluated for association with 30-day mortality by logistic regression analysis. Kaplan-Meier estimate was used to evaluate survival with no loss to follow-up. Results -- 437 patients had aBM surgery with EPR/IF. No parameters describing the magnitude of the surgical trauma (blood loss/duration of surgery/degree of bone resection) were associated with mortality. Overall 30-day survival was 85% (95% confidence interval [CI] 81-88). Univariate analysis identified ASA group 3+4, Karnofsky score < 70, fast-growth primary cancer, and visceral and multiple bone metastases as risk factors for 30-day mortality. Male sex (OR 2.8, CI 1.3-6.3), Karnofsky score < 70 (OR 4.2, CI 2.1-8.6), and multiple bone metastases (OR 3.4, CI 1.2-9.9) were independent prognostic factors for 30-day-mortality in multivariate analysis. Conclusion -- The parameters describing the surgical trauma were not associated with 30-day mortality but, instead, general health status and extent of primary cancer influenced survival post-surgery. [ABSTRACT FROM AUTHOR]

Background and purpose -- Systemic antibiotic prophylaxis with clindamycin, which is often used in penicillin- or cephalosporin-allergic patients', has been associated with a higher risk of surgical revision for deep prosthetic joint infection (PJI) than cloxacillin in primary total knee replacement (TKR). We aimed to investigate whether clindamycin increases the risk of surgical revisions due to PJI compared with cephalosporins in primary cemented TKR. Patients and methods -- Data from 59,081 TKRs in the Norwegian Arthroplasty Register (NAR) 2005-2020 was included. 2,655 (5%) received clindamycin and 56,426 (95%) received cephalosporins. Cox regression analyses were performed with adjustment for sex, age groups, diagnosis, and ASA score. Survival times were calculated using Kaplan-Meier estimates and compared using Cox regression with revision for PJI as endpoint. The cephalosporins cefalotin and cefazolin were also compared. Results -- Of the TKRs included, 1.3% (n = 743) were revised for PJI. 96% (n = 713) had received cephalosporins and 4% (n = 30) clindamycin for perioperative prophylaxis. Comparing cephalosporins (reference) and clindamycin, at 3-month follow-up the adjusted hazard ratio rate (HRR) for PJI was 0.7 (95% confidence interval [CI] 0.4-1.4), at 1 year 0.9 (CI 0.6-1.5), and at 5 years 0.9 (CI 0.6-1.4). Analysis using propensity score matching showed similar results. Furthermore, comparing cefalotin (reference) and cefazolin, HRR was 1.0 (CI 0.8-1.4) at 3 months and 1.0 (CI 0.7-1.3) at 1-year follow-up. Conclusion -- We found no difference in risk of revision for PJI when using clindamycin compared with cephalosporins in primary cemented TKRs. It appears safe to continue the use of clindamycin in penicillin- or cephalosporin-allergic patients. [ABSTRACT FROM AUTHOR]

Background and purpose -- Studies evaluating pain and patient-reported outcome measures (PROMs) related to type of revision total hip arthroplasty (rTHA) are sparse. Our aim was to compare pain, physical function, quality of life, and patient satisfaction among different types of aseptic rTHA at 1-year follow-up. Patients and methods -- We performed a retrospective study from an institutional registry with 426 primary THAs scheduled for rTHA in a fast-track setting between 2012 and 2021. Revisions were grouped by 4 types of surgery: head and/or liner exchange, cup revision, stem revision, and cup and stem revision. Pain during mobilization and at rest (NRS 0-10), physical function (HOOS-PS and HHS) and health-related quality of life (EQ-5D) were registered preoperatively, at 3 months, and 1 year postoperatively. Patient satisfaction was surveyed at the 1-year follow-up by 2 questions related to hip function and willingness to undergo the same surgery. Results -- With a response rate of 85%, all outcomes improved in the 4 groups but there were neither statistical nor clinical differences between types of rTHA at 1-year follow-up. NRS pain during mobilization improved overall by 2.7 (95% confidence interval 2.3-3.1) until 1-year follow-up, both being statistically significant and clinically relevant. The improvements were mainly seen at the 3-month followup, with minor progress observed at 1 year. About 80% reported improved hip function and willingness to undergo the surgery again at the 1-year follow-up. Conclusion -- Significant improvements in NRS pain and PROMS were found in all groups after rTHA, with no group differences at 1 year. This is relevant preoperative information for both clinicians and patients eligible for rTHA. [ABSTRACT FROM AUTHOR]

Background and purpose -- The incidence of periprosthetic joint infection after total hip arthroplasty (THA) may be increasing. We performed time-trend analyses of risk, rates, and timing of revision due to infection after primary THAs in the Nordic countries from the period 2004-2018. Patients and methods -- 569,463 primary THAs reported to the Nordic Arthroplasty Register Association from 2004 to 2018 were studied. Absolute risk estimates were calculated by Kaplan-Meier and cumulative incidence function methods, whereas adjusted hazard ratios (aHR) were assessed by Cox regression with the first revision due to infection after primary THA as primary endpoint. In addition, we explored changes in the time span from primary THA to revision due to infection. Results -- 5,653 (1.0%) primary THAs were revised due to infection during a median follow-up time of 5.4 (IQR 2.5-8.9) years after surgery. Compared with the period 2004-2008, the aHRs for revision were 1.4 (95% confidence interval [CI] 1.3-1.5) for 2009-2013, and 1.9 (CI 1.7-2.0) for 2014-2018. The absolute 5-year rates of revision due to infection were 0.7% (CI 0.7-0.7), 1.0% (CI 0.9-1.0), and 1.2% (CI 1.2-1.3) for the 3 time periods respectively. We found changes in the time span from primary THA to revision due to infection. Compared with 2004-2008, the aHR for revision within 30 days after THA was 2.5 (CI 2.1-2.9) for 2009-2013, and 3.4 (CI 3.0-3.9) for 2013-2018. The aHR for revision within 31-90 days after THA was 1.5 (CI 1.3-1.9) for 2009-2013, and 2.5 (CI 2.1-3.0) for 2013-2018, compared with 2004-2008. Conclusion -- The risk of revision due to infection after primary THA almost doubled, both in absolute cumulative incidence and in relative risk, throughout the period 2004-2018. This increase was mainly due to an increased risk of revision within 90 days of THA. This may reflect a "true" increase (i.e., frailer patients or more use of uncemented implants) and/or an "apparent" increase (i.e., improved diagnostics, changed revision strategy, or completeness of reporting) in incidence of periprosthetic joint infection. It is not possible to disclose such changes in the present study, and this warrants further research. [ABSTRACT FROM AUTHOR]

Background and purpose -- The bearings with the best survivorship for young patients with total hip arthroplasty (THA) should be identified. We compared hazard ratios (HR) of revision of primary stemmed cementless THAs with metal-on-metal (MoM), ceramic-on-ceramic (CoC), and ceramic-on-highly-crosslinked-polyethylene (CoXLP) with that of metal-on-highly-crosslinked-polyethylene (MoXLP) bearings in patients aged 20-55 years with primary osteoarthritis or childhood hip disorders. Patients and methods -- From the Nordic Arthroplasty Register Association dataset we included 1,813 MoM, 3,615 CoC, 5,947 CoXLP, and 10,219 MoXLP THA in patients operated on between 2005 and 2017 in a prospective cohort study. We used the Kaplan-Meier estimator for THA survivorship and Cox regression to estimate HR of revision adjusted for confounders (including 95% confidence intervals [CI]). MoXLP was used as reference. HRs were calculated during 3 intervals (0-2, 2-7, and 7-13 years) to meet the assumption of proportional hazards. Results -- Median follow-up was 5 years for MoXLP, 10 years for MoM, 6 years for CoC, and 4 years for CoXLP. 13-year Kaplan-Meier survival estimates were 95% (CI 94-95) for MoXLP, 82% (CI 80-84) for MoM, 93% (CI 92-95) for CoC, and 93% (CI 92-94) for CoXLP bearings. MoM had higher 2-7 and 7-13 years' adjusted HRs of revision (3.6, CI 2.3-5.7 and 4.1, CI 1.7-10). MoXLP, CoC, and CoXLP had similar HRs in all 3 periods. The 7-13-year adjusted HRs of revision of CoC and CoXLP were statistically non-significantly higher. Conclusion -- In young patients, MoXLP for primary cementless THA had higher revision-free survival and lower HR for revision than MoM bearings. Longer follow-up is needed to compare MoXLP, CoC, and CoXLP. [ABSTRACT FROM AUTHOR]

Background and purpose -- Scheuermann's disease is characterized by kyphosis and frequently mild back pain. As the level of kyphosis may progress over time, also the level of pain may increase. We evaluated the prevalence of Scheuermann's disease, and their pain, in Swedish elderly men. Patients and methods -- The Osteoporotic Fractures in Men (MrOS) Study Sweden (n = 3,014) is a population-based prospective observational study of community-living men aged 69-81 years. At baseline, participants answered a questionnaire including history of neck/back pain during the preceding year and characteristics of any pain (severity, sciatica, and neurological deficits). Lateral thoracic/lumbar spine radiographs were taken of 1,453 men. We included the 1,417 men with readable radiographs. Scheuermann's disease was defined as 3 or more consecutive vertebrae with > 5° wedging with no other explanation for the deformity. Results -- 92 of the 1,417 men (6.5%, 95% confidence interval 5.3-7.9) had Scheuermann's disease. 31% of men with and 31% without Scheuermann's disease reported neck pain (P = 0.90) and 51% with and 55% without the disease reported back pain (P = 0.4). Among men with Scheuermann's disease and back pain, none reported severe pain, 57% moderate, and 43% mild, compared with 7%, 50%, and 44% in those without Scheuermann's disease (P = 0.2). In those with Scheuermann's disease 63% reported no sciatica, 15% sciatica without neurological deficits, and 22% sciatica with neurological deficits, compared with 56%, 16%, and 28% in those without the disease (P = 0.6). Conclusion -- The prevalence of Scheuermann's disease in elderly Swedish men is between 5.3% and 7.9%. The condition seems at this age not to be associated with neck or back pain. [ABSTRACT FROM AUTHOR]

Background and purpose -- Radiostereometric analysis (RSA) is the gold standard for migration analysis, but computed tomography analysis methods (CTRSA) have shown comparable results in other joints. We attempted to validate precision for CT compared with RSA for a tibial implant. Material and methods -- RSA and CT were performed on a porcine knee with a tibial implant. Marker-based RSA, model-based RSA (MBRSA), and CT scans from 2 different manufacturers were compared. CT analysis was performed by 2 raters for reliability evaluation. Results -- 21 double examinations for precision measurements for RSA and CT-based Micromotion Analysis (CTMA) were analysed. Mean (95% confidence interval) precision data for maximum total point motion (MTPM) using marker-based RSA was 0.45 (0.19-0.70) and 0.58 (0.20-0.96) using MBRSA (F-statistic 0.44 [95% CI 0.18-1.1], p = 0.07). Precision data for total translation (TT) for CTMA was 0.08 (0.03-0.12) for the GE scanner and 0.11 (0.04-0.19) for the Siemens scanner (F-statistic 0.37 [0.15-0.91], p = 0.03). When comparing the aforementioned precision for both RSA methods with both CTMA analyses, CTMA was more precise (p < 0.001). The same pattern was seen for other translations and migrations. Mean effective radiation doses were 0.005 mSv (RSA) (0.0048-0.0050) and 0.08 mSv (CT) (0.078-0.080) (p < 0.001). Intra- and interrater reliability were 0.79 (0.75-0.82) and 0.77 (0.72-0.82), respectively. Conclusion -- CTMA is more precise than RSA for migration analysis of a tibial implant, has overall good intra- and interrater reliability but higher effective radiation doses in a porcine cadaver. [ABSTRACT FROM AUTHOR]

Background and purpose -- Assessing peri-acetabular bone quality is valuable for optimizing the outcomes of primary total hip arthroplasty (THA) as preservation of good quality bone stock likely affects implant stability. The aim of this study was to perform a meta-analysis of peri-acetabular bone mineral density (BMD) changes over time measured using quantitative computer tomography (CT) and, second, to investigate the influence of age, sex, and fixation on the change in BMD over time. Methods -- A systematic search of Embase, Scopus, Web of Science, and PubMed databases identified 19 studies that measured BMD using CT following THA. The regions of interest (ROI), reporting of BMD results, and scan protocols were extracted. A meta-analysis of BMD was performed on 12 studies that reported measurements immediately postoperatively and at follow-up. Results -- The meta-analysis determined that periacetabular BMD around both cemented and uncemented components decreases over time. The amount of BMD loss increased relative to proximity of the acetabular component. There was a greater decrease in cortical BMD over time in females and cancellous BMD for young patients of any sex. Conclusion -- Peri-acetabular BMD decreases at different rates relative to its proximity to the acetabular component. Cancellous BMD decreases more in young patients and cortical bone decreases more in females. Standardized reporting parameters and suggested ROI to measure peri-acetabular BMD are proposed, to enable comparison between implant and patient variables in the future. [ABSTRACT FROM AUTHOR]

Background and purpose -- The management of acute hematogenous periprosthetic joint infection (AHI) is challenging and the optimal treatment is not clearly defined. The aim of this study was to evaluate the treatment outcome of AHI, and secondarily to investigate potential risk factors that affect outcome. Patients and methods -- We retrospectively analyzed 43 consecutive AHIs in a total hip or knee arthroplasty between 2013 and 2020 at a single center. We used the Delphi international consensus criteria to define infection. Patients were treated by either debridement, antibiotics, and implant retention (DAIR) (n = 25), implant exchange/removal (n = 15), or suppressive antibiotics only (n = 3). AHI was defined as abrupt symptoms of infection ≥ 3 months after implantation in an otherwise well-functioning arthroplasty. Results -- AHI was most often caused by Staphylococcus aureus (16/43) and streptococcal species (13/43), but a broad spectrum of microbes were identified. 25 of 43 were treated with DAIR, with success in 10 of 25, which was significantly lower than in patients treated with removal of the implant with success in 14 of 15. S. aureus infection, knee arthroplasty, and implant age < 2 years were associated with treatment failure. The 2-year mortality rate was 8 of 43. Conclusion -- The outcome following DAIR in AHIs was poor. The majority of infections were caused by virulent microbes, and we found a high mortality rate. Removal of the implant should more often be considered. [ABSTRACT FROM AUTHOR]

Background and purpose -- Long-term follow-up of young patients following cemented primary THA is scarce. Therefore, we analyzed the survival of all consecutive primary THAs in patients under 25 years performed at our institute. Patients and methods -- All primary THAs performed in patients younger than 25 years in our tertiary care institute between 1988 and 2015 were included (n = 119). Cemented fixation was used in all patients. In the case of acetabular bone deficiencies, reconstruction was performed using impaction bone grafting (IBG). We used Kaplan-Meier analysis to determine the survival of the primary THA with endpoints revision for any reason and aseptic loosening. Results -- The mean age at the primary THA was 20 years. The most prevalent diagnosis was avascular necrosis (31%). The mean follow-up of the primary THA was 11 years (range 0-32). 2 patients (2 hips) were lost to follow-up. 16 revisions were registered. The survival of any component for endpoint revision for any reason was estimated at 92% (95% confidence interval [CI] 84-96) and 81% (CI 67-90) at 10- and 15-year follow-up, respectively. The survival of any component for endpoint revision for aseptic loosening was 99% (CI 93-100) and 88% (CI 71-95) at 10 and 15 years, respectively. 3 hips were revised due to infection. Conclusion -- Favorable long-term outcomes of primary THA in very young patients can be obtained using cemented fixation and IBG. [ABSTRACT FROM AUTHOR]

Background and purpose Hip fractures are associated with high mortality, but the cause of this is still not entirely clear. We investigated the effect of surgical delay, weekends, holidays, and time of day admission on mortality in hip fracture patients. Patients and methods Using data from the Danish National Indicator Project, we identified 38,020 patients admitted from 2003 to 2010. Logistic regression analysis was used to study the association between sex, age, weekend or holiday admission, night-time admission, time to surgery, and ASA score on the one hand and mortality on the other. Results The risk of death in hospital increased with surgical delay (odds ratio (OR) = 1.3 per 24 h of delay), ASA score (OR (per point added) = 2.3), sex (OR for men 2.2), and age (OR (per 5 years) = 1.4). The mortality rate for patients admitted during weekends or public holidays, or at night, was similar to that found for those admitted during working days. Interpretation Minimizing surgical delay is the most important factor in reducing mortality in hip fracture patients. [ABSTRACT FROM AUTHOR]

Background and purpose -- Intraoperative periprosthetic femoral fractures (IPFFs) can occur during primary total hip arthroplasty (THA). We describe the incidence of IPFFs during THA in Norway and estimate potential risk factors that could be associated with IPFF Patients and methods -- Data from the Norwegian Arthoplasty Register (1987--2020) was used: 2,268 IPFFs from 218,423 primary THAs in 172,598 patients. The following factors were analyzed: sex, age, diagnosis, previous operation on the same hip, surgical approach, and stem fixation technique. Association of these factors with IPFF risk was assessed using multivariable Poisson regression. Results -- IPFF occurred during 2,268 operations with an incidence of 1.0% among all primary THAs. The risk of IPFF was associated with female sex (relative risk 1.8; 99% CI 1.5--2.1), age 80--90 years and age over 90 years (compared with age 60--70 years: 1.3; CI 1.0--1.6 and 2.6; CI 1.6--4.3, respectively), non-osteoarthritis diagnoses (2.2; CI 1.9--2.6), previous surgery to the same hip (1.8; CI 1.5--2.2), lateral approach (compared with the posterior approach: 1.5; CI 1.1--2.0), and cementless stem fixation (2.7; CI 2.0--3.6). Interpretation -- Surgeons should be aware of the factors associated with an increased risk of IPFF: female sex, age above 80 years, non-osteoarthritis diagnoses, and previous surgery to the same hip. Cemented stem fixation and posterior approach should be favored in high-risk patients, such as elderly women. [ABSTRACT FROM AUTHOR]

Background and purpose -- Knowledge regarding patient-reported outcomes (PROs) after dislocation and closed reduction is lacking. We report health- and hip-related quality of life (QoL) after dislocation, following primary total hip arthroplasty (THA). Patients and methods -- We conducted a crosssectional study with patients registered in the Danish Hip Arthroplasty Register from 2010 to 2014. Dislocations were captured based on diagnosis/procedure codes and patient file reviews. Patients with dislocation were matched 1:2, according to age, sex, date, and hospital of primary surgery, to patients without dislocation. 2 PRO questionnaires were applied (EQ-5D, HOOS). Results -- We identified 1,010 living patients with dislocation. Mean follow-up was 7.2 years from index surgery and 4.9 years (range 0.6--9.7) from the latest dislocation. Patients without dislocation reported a higher EQ VAS score of 76 (95% CI 75--77) compared with 68 (CI 66--70) for the dislocation group. The EQ-5D-5L mean index score was 0.89 (CI 0.88--0.90) for the control group, compared with 0.78 (CI 0.76--0.80) for the cases with dislocation without revision. Patients with dislocation reported a lower HOOSQoL domain score of 63 (CI 60--65), compared with 83 (CI 82--84) for the control group. Even 5 years after the latest dislocation, the HOOS-QoL score remained low, at 66 (CI 62--69). The other HOOS domains were consistently 8--10 points worse after dislocation. Interpretation -- Both health- and hip-related QoL were markedly and persistently reduced among dislocation patients compared with those in controls, for several years. Therefore, the avoidance of the initial dislocation episode is important because the THA does not appear to achieve the full relieving potential. [ABSTRACT FROM AUTHOR]

Background and purpose -- After initial clubfoot correction through Ponseti treatment, recurrence rates range from 26% to 48%. Even though various factors have been associated with increased recurrence risk, systematic assessments of the prognostic capacity of recurrence risk factors and their clinical relevance are lacking. Therefore we assessed clinically relevant prognostic factors for recurrent idiopathic clubfoot deformity after initial correction through Ponseti treatment. Methods -- PubMed, Embase, Cinahl, and Web of Science were systematically searched for studies investigating the association between clinically relevant factors and recurrence rates. Prognostic factors were qualitatively assessed and included in the meta-analysis if ≥ 2 studies investigated the same factor and methods were comparable. Results -- 34 articles were included in the qualitative synthesis, of which 22 were also included in the meta-analysis. Meta-analysis revealed that poor evertor muscle activity (OR = 255, 95% CI 30--2,190), brace non-compliance (OR = 10, CI 5--21), no additional stretching (OR = 31, CI 10--101), more casts (OR = 3.5, CI 1.6--7.8), lower education level of parents (OR = 1.8, CI 1.2--2.6), non-marital status of parents (OR = 1.8, CI 1.1--3.0), and higher Dimeglio scores (OR = 1.9, CI 1.2--3.3) were associated with higher recurrence rates. Interpretation -- Brace non-compliance and poor evertor muscle activity have been identified as main recurrence risk factors and are therefore important to be closely monitored during clinical follow-up of clubfoot patients. Adding additional stretching during the bracing protocol might be promising in the quest to prevent relapse, but scientific evidence for clear clinical treatment recommendations is still limited. [ABSTRACT FROM AUTHOR]

Background and purpose -- Surgical site infection (SSI) after hip fracture surgery is a feared condition. We examined the trend in incidence of reoperation due to SSI up to 1 year following hip fracture surgery from 2005 to 2016 and risk factors of SSI by age, sex, comorbidity, type of fracture, and surgery. Patients and methods -- We conducted a populationbased, nationwide cohort study using data from the Danish Multidisciplinary Hip Fracture Register (DMHFR). We included 74,771 patients aged 65 and up who underwent surgery from 2005 to 2016 for all types of hip fracture. We calculated net risk of reoperation using Kaplan--Meier method, and, with Cox regression, adjusted hazard ratios (HRs) with a 95% confidence interval (CI) for reoperation due to SSI. Results -- Overall, the 1-year net risk of reoperation due to SSI was 1.6%. The HR was higher for patients undergoing total/hemiarthroplasty surgery versus internal fixation (HR = 1.5; 95%CI 1.3--1.8) and lower for patients with per-/subtrochanteric fracture versus femoral neck fracture (HR = 0.6; CI 0.6--0.7). The risk of reoperation due to SSI decreased over time; HR was 0.7 (CI 0.5--0.8) for 2015--2016 compared with 2005--2006. Risk of reoperation decreased with increasing age; the HR was 0.8 (CI 0.7--1.0) in the more than 85-year-olds compared with 65--74-year-old patients. Charlson Comorbidity Index of ≥ 3 was associated with a higher risk of reoperation due to SSI, HR was 1.3 (CI 1.1--1.6). Interpretation -- The net risk of reoperations due to SSI in our study was lower than previously assumed. We identified several risk factors for increased risk of reoperation due to SSI, most noticeably treatment with arthroplasty vs. internal fixation, as well as younger age, high comorbidity burden, and femoral neck fracture diagnosis. [ABSTRACT FROM AUTHOR]

Background and purpose -- Identification of pathogens causing fracture-device-related infection (FDRI) is always a challenge as the positive rate of standard tissue sampling culture (TSC) remains unsatisfactory. This study evaluates the efficiency of implant surface culture (ISC) as an adjunct to standard TSC for identification of FDRI-associated microorganisms. Patients and methods -- Between November 2020 and March 2022, patients diagnosed with FDRI defined by the International Fracture-Related Infection (FRI) Consensus Group, and indicated for implant removal, underwent both methods for bacteria detection. The test order of ISC and TSC was randomly selected for each patient included, as a withinperson randomized design. For ISC, the recovered implants were gently covered with tryptic soy agar after rinsing with normal saline twice, and then incubated at 37 5% CO2 for up to 14 days. For TSC, 5 specimens were sampled and sent to the Clinical Laboratory of Southern Medical University Nanfang Hospital, Guangzhou, for culture and identification. Results -- 42 consecutive patients were included, with a mean age of 46 years. The most frequent infection site and implant type were the tibia (21 cases) and plates with screws (30 cases), respectively. Altogether 21 patients were found with positive outcomes by both methods, and the identi- fied pathogens were consistent. ISC found an additional 15 patients showing positive results, which were negative by TSC. Furthermore, the mean culture time of ISC was shorter than that of TSC (1.5 days vs. 3.2 days). Interpretation -- ISC may be a useful adjunct to TSC for detection of bacteria causing FDRI, with a relatively higher positive rate and a shorter culture time. [ABSTRACT FROM AUTHOR]

Background and purpose -- Developing meaningful thresholds for the Oxford Knee Score (OKS) advances its clinical use. We determined the minimal important change (MIC), patient acceptable symptom state (PASS), and treatment failure (TF) values as meaningful thresholds for the OKS at 3-, 12-, and 24-month follow-up in patients undergoing unicompartmental knee arthroplasty (UKA). Patients and methods -- This is a cohort study with data from patients undergoing UKA collected at a hospital in Denmark between February 2016 and September 2021. The OKS was completed preoperatively and at 3, 12, and 24 months postoperatively. Interpretation threshold values were calculated with the anchor-based adjusted predictive modeling method. Non-parametric bootstrapping was used to derive 95% confidence intervals (CI). Results -- Complete 3-, 12-, and 24-month postoperative data was obtained for 331 of 423 (78%), 340 of 479 (71%), and 235 of 338 (70%) patients, median age of 68--69 years (58--59% females). Adjusted OKS MIC values were 4.7 (CI 3.3--6.0), 7.1 (CI 5.2--8.6), and 5.4 (CI 3.4--7.3), adjusted OKS PASS values were 28.9 (CI 27.6--30.3), 32.7 (CI 31.5-- 33.9), and 31.3 (CI 29.1--33.3), and adjusted OKS TF values were 24.4 (CI 20.7--27.4), 29.3 (CI 27.3--31.1), and 28.5 (CI 26.0--30.5) at 3, 12, and 24 months postoperatively, respectively. All values statistically significantly increased from 3 to 12 months but not from 12 to 24 months. Interpretation -- The UKA-specific measurement properties and clinical thresholds for the OKS can improve the interpretation of UKA outcome and assist quality assessment in institutional and national registries. [ABSTRACT FROM AUTHOR]

Background and purpose -- During the first COVID-19 lockdown elective surgery was greatly reduced. Prioritization of patients with greater need and expected benefit in terms of quality of life was advised. The lockdown also potentially affected follow-up outcomes. Therefore, our study compared patient-reported outcome measures (PROMs) retrieved during the lockdown of Dutch primary total hip and knee arthroplasty (THA, TKA) patients with previous years. Patients and methods -- We performed cross-sectional analyses using national data from the Dutch Orthopaedic Registry (LROI). All primary elective THA and TKA patients with preoperative or postoperative PROMs (EQ-5D-3L index, OHS/OKS) during the first COVID-19 lockdown between March and July 15, 2020 were included. Patients with PROMs during the same months in 2018 plus 2019 were used as control. Finally, 33,453 THA and 27,335 TKA patients were included. Patient characteristics were compared during versus before the lockdown. Subsequently, the lockdown effect on PROMs scores was analyzed with multivariable linear regression. Results -- During the COVID-19 lockdown, THA and TKA patients had a lower age and BMI preoperatively, and more often had surgery in private clinics. Both preoperative PROMs in THA patients, but not in TKA patients, were worse (EQ-5D: Adjusted mean difference (AMD) --0.021, p < 0.001) during the lockdown compared with prior years. Both postoperative PROMs in THA and TKA patients were better during the lockdown (12-month EQ-5D in THA: AMD 0.010, p = 0.003; and in TKA: AMD 0.013, p < 0.001). Interpretation -- During the COVID-19 lockdown, THA patients had slightly worse preoperative PROMs, suggesting selection of patients with greater urgency. Postoperative PROMs in both THA and TKA patients differed minimally. Overall, the observed differences were likely not clinically relevant. [ABSTRACT FROM AUTHOR]

Background and purpose -- Total hip (THA) and knee (TKA) arthroplasty are effective pain treatment in osteoarthritis; however, there are patients with long-term pain and in need of analgesics. We studied purchases of paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), opioids, and neuropathic pain medication before and after THA or TKA. Patients and methods -- We searched all THA (n = 149,158) and TKA (n = 180,585) cases in Finland between the years 1998 and 2018 and the drug purchases made by patients during 1997--2018 using linked Finnish register data. Drug purchases were studied in 3-month periods. Results -- The purchases of all analgesics increased from 3 years before operation to 3 months before operation. Around the time of THA or TKA, the purchases of all analgesics spiked to 7--56%, depending on drug. The purchases of all analgesics decreased rapidly during the first 6 months postoperatively. Purchases of paracetamol, NSAIDs, and opioids at 6 months postoperatively (6--23%) were lower than they were at 3 months preoperatively. At 3 years postoperatively, only paracetamol purchases were lower (15--18%) postoperatively than they were 3 years before arthroplasty. NSAID, opioid, and neuropathic pain medication purchases remained higher (4--14%). Interpretation -- THA and TKA stop and reduce the preoperative increases in purchases of paracetamol, NSAIDs, and opioids. The purchases of pain medications by THA and TKA patients 1 year after operation are close to those in the general population. [ABSTRACT FROM AUTHOR]

Background and purpose -- Although most patients have good outcomes after shoulder arthroplasty for osteoarthritis, certain risk factors may lead to disappointing outcomes. We assessed risk factors for a worse outcome after anatomical shoulder arthroplasty for osteoarthritis. Our hypothesis was that previous surgery for instability would be a risk factor for a worse outcome independent of age, sex, and arthroplasty type. Patients and methods -- We included arthroplasties reported to the Danish Shoulder Arthroplasty Registry between 2006 and 2018 (n = 3,743). The Western Ontario Osteoarthritis of the Shoulder (WOOS) index at 1 year was used as outcome. The total score was converted to a percentage of a maximum score. The general linear model was used to analyze differences in WOOS. Age, sex, arthroplasty type, and previous surgery were included in the multivariate model. Estimates were given with 95% confidence intervals (CI). Results -- The mean WOOS score was 78 for patients with no previous surgery and 55 for patients with surgery for instability. The mean difference was --16 (CI --10 to --22) in the multivariate model. Hemiarthroplasty had a worse outcome compared with total shoulder arthroplasty and young patients had a worse outcome compared with older patients. The mean differences in the multivariate model were --12 (CI --10 to --14) and --11 (CI --8 to --14) respectively. Interpretation -- Patients with previous surgery for instability had worse results independent of age, sex, and arthroplasty type and should be informed about their individual risk of a worse outcome. [ABSTRACT FROM AUTHOR]

Background and purpose -- Over the last decades, many countries have shown increased surgery rates for lumbar spinal stenosis (LSS), but little information is available from Denmark. We describe the development in diagnosis and surgery of LSS in Denmark between 2002 and 2018. Patients and methods -- We collected diagnostic ICD10-codes and surgical procedure codes from private and public hospitals in Denmark from the Danish National Patient Register. Patients diagnosed with LSS and those with surgical procedure codes for decompression surgery with or without fusion were identified. Annual surgery rates were stratified by age, sex, and type of surgery. Results -- During these 17 years, 132,138 patients diagnosed with LSS and 43,454 surgical procedures for LSS were identified. The number of surgical procedures increased by 144%, from 23 to 56 per 100,000 inhabitants. The proportion of patients diagnosed with LSS who received surgery was about 33%, which was almost stable over time. Decompression without fusion increased by 128% from 18 to 40 per 100,000 inhabitants and decompression with fusion increased by 199%, from 5 to 15 per 100,000. Interpretation -- Both the prevalence of LSS diagnoses and LSS surgery rates more than doubled in Denmark between 2002 and 2018. However, the proportion of patients diagnosed with LSS who received surgery remained stable. Decompression surgery with fusion increased at a higher rate than decompression without fusion, although recent evidence suggests no advantage of decompression plus fusion over decompression alone. [ABSTRACT FROM AUTHOR]

Background and purpose -- BoneMaster (BM) is a thin electrochemically applied hydroxyapatite (HA) implant coating marketed with expectations of improved osseointegration properties but less polyethylene (PE) wear. We compared the midterm cup migration and PE wear of cementless porous-coated hemispherical cups with and without BM. Patients and methods -- In this patient-blinded, randomized controlled trial, 53 patients with a mean age of 64 years (55--75) received total hip arthroplasty with a porouscoated (P) or porous and BoneMaster (PBM) coated Exceed cup and ArCom E1 infused PE. Patients were followed with RSA, Hip Osteoarthritis Outcome Score (HOOS), and Euro- Qol-5-3L (EQ-5D) at 3 and 6 months, and 1-, 2-, and 5-year follow-up. Results -- At 5-year follow-up, total translation and maximum total point motion was 0.28 mm (95% CI 0.08; 0.47) and 0.52 mm (CI 0.12; 0.93) higher in the PBM group than in the P group. PE wear was comparable between PBM and P cups, and 2D wear rate from 1 year follow-up to last follow-up was 0.03 mm (CI 0.02--0.03). The 5-year anterior translation was 0.05 mm (CI --0.10 to 0.21) in the normal BMD group and 0.40 mm (CI 0.22--0.57) in the osteopenia group. Interpretation -- At 5-year follow-up, Exceed cups in the PBM group migrated more than in the P group but the PE wear rate was low and similar. This study does not indicate any advantage of additional BoneMaster coating compared with porous coating alone on cementless hemispherical cups with regards to migration, polyethylene wear, and clinical outcomes. [ABSTRACT FROM AUTHOR]

Background and purpose -- Results regarding the impact of anticoagulants on revision rate are conflicting. We examined the association between the use of low molecular weight heparin (LMWH) or non-vitamin K oral anticoagulants (NOACs) as thromboprophylaxis after primary total hip arthroplasty (THA) and the revision rate due to infection, aseptic loosening, and all causes. Patients and methods -- We conducted a cohort study (n = 53,605) based on prospectively collected data from the national hip arthroplasty registries from Denmark and Norway. The outcome was time to revision due to infection, aseptic loosening, and all causes, studied separately. Kaplan-- Meier (KM) survival analysis and a Cox proportional hazard model was used to estimate implant survival and cause-specific hazard ratios (HRs) with 95% confidence intervals (CI) adjusting for age, sex, Charlson Comorbidity Index, fixation type, start, and duration of thromboprophylaxis, and preoperative use of Vitamin K antagonists, NOAC, aspirin, and platelet inhibitors as confounders. Results -- We included 40,451 patients in the LMWH group and 13,154 patients in the NOAC group. Regarding revision due to infection, the 1-year and 5-year KM survival was 99% in both the LMWH group and in the NOAC group. During the entire follow-up period, the adjusted HR for revision due to infection was 0.9 (CI 0.7--1.1), 1.6 (CI 1.3--2.1) for aseptic loosening, and 1.2 (CI 1.1--1.4) for all-cause revision for the NOAC compared with the LMWH group. The absolute differences in revision rates between the groups varied from 0.2% to 1%. Interpretation -- Compared with LMWH, NOACs were associated with a slightly lower revision rate due to infection, but higher revisions rates due to aseptic loosening and all-cause revision. The absolute differences between groups are small and most likely not clinically relevant. In addition, the observed associations might partly be explained by selection bias and unmeasured confounding, and should be a topic for further research. [ABSTRACT FROM AUTHOR]

Background and purpose -- High alcohol intake is associated with increased risk of postoperative complications. Alcohol cessation intervention is recommended prior to elective surgery. We investigated short- and long-term effects of perioperative intensive alcohol intervention in relation to acute ankle fracture surgery. Patients and methods -- 70 patients requiring ankle fracture surgery and consuming ≥ 21 drinks weekly (1 drink = 12 g ethanol) were randomized to a manual-based 6-week intensive standardized alcohol cessation program, the Gold Standard Program (GSP-A), or treatment as usual (TAU), on the day of operation. GSP-A included 5 personal meetings, patient education, and motivational and pharmacological support (alcohol withdrawal prophylaxis, B vitamins, and low-dose disulfiram). Complications requiring treatment were measured after 6 weeks and 1 year. Alcohol intake was validated by biomarkers. Quality of life (QoL) was measured by the SF-36. Hospital costs were obtained from the National Hospital Costs Register. Results -- Postoperatively, complete alcohol cessation was higher in the GSP-A than in the TAU group (18/35 vs. 5/35, number needed to treat = 3, p ≤ 0.001), but not lowrisk consumption in the long term (10/35 vs. 7/33, p = 0.5). Number of complications in the short and long term (12/35 vs. 14/33, 16/35 vs. 18/33), the SF-36 score, or hospital costs in the short and long term (€6,294 vs. €8,024, €10,662 vs. €12,198), were similar between the groups. Interpretation -- Despite an effect on alcohol cessation and a positive tendency as regards the other outcomes, the postoperative complications, QoL, and costs were similar. Better perioperative strategies for acute surgical patients with high alcohol intake therefore need to be developed. [ABSTRACT FROM AUTHOR]

Background and purpose -- The Taperloc Complete hip is the successor of the Taperloc hip, aiming to increase range of motion and optimizing femoral fit with intermediate stem sizes. We evaluated whether these design changes affect fixation, and this RSA study compares 2-year migration. Patients and methods -- In this prospective, multi-arm study, 100 patients were randomized to cementless total hip arthroplasty (THA) with Taperloc Complete full profile (TCFP), Taperloc Complete reduced distal (TCRD), Taperloc full profile (TFP), or Taperloc reduced distal (TRD). Migration was measured with model-based RSA postoperatively, and after 3, 12, and 24 months. Results -- Results based on mixed-model analysis on 2-year postoperative RSA data from 74 patients showed similar subsidence (mm) in the first 3 months (mean [95% CI] TCFP 0.44 [0.20--0.69], TCRD 0.91 [0.40--1.42], TFP 0.71 [0.22--1.19], TRD 1.25 [0.58--1.91]) and stabilization afterwards. The TCFP showed statistically significantly less retroversion (°) at 2-year postoperatively compared with TFP and TCRD (mean [95% CI] TCFP: --0.13 [--0.64 to 0.38], TCRD: 0.84 [0.35--1.33], TFP: 0.56 [0.12--1.00], TRD: 0.37 [--0.35 to 1.09]). Interpretation -- As expected in successful cementless THA, RSA shows stabilization after initial subsidence. Based on these results the Taperloc Complete stem is expected to have similar long-term fixation to the Taperloc stems. The reduced distal groups have larger, but statistically non-significant, initial migration compared with the TCFP group, which could be due to implantation in Dorr B, C femur types. It may be important to consider the femur shape for choosing a full profile or reduced distal stem to minimize migration. [ABSTRACT FROM AUTHOR]

Background and purpose — The UCLA Activity Scale (UCLA) is a questionnaire assessing physical activity level from 1 (low) to 10 (high) in patients undergoing hip or knee arthroplasty (HA/KA). After translation and cultural adaptation, we evaluated the measurement properties of the Danish UCLA. Patients and methods — After dual panel translation, cognitive interviews were performed among 55 HA/KA patients. An orthopedic surgeon and a physiotherapist estimated UCLA scores for 80 KA patients based on short interviews. Measurement properties were evaluated in 130 HA and 134 KA patients preoperatively and 1-year postoperatively. Results — To suit Danish patients of today, several adaptations were required. Prior to interviews, 4 patients were excluded, and 11 misinterpreted the answer options. Examiners rated the remaining 65 patients (mean age 67 years) 0.2–1.6 UCLA levels lower than patients themselves. The 130 HA and 134 KA patients (mean age 71/68 years) changed from 4.3 (SD 1.9)/4.5 (1.8) preoperatively to 6.6 (1.8)/6.2 (1.0) at 1-year follow-up. 103 (79%) HA and 89 (66%) KA patients reported increased activity. Effect sizes were large (1.2/0.96). Knee patients reaching minimal important change (MIC, ≥ 8 Oxford Knee Score points) had higher 1-year UCLA scores than patients not reaching MIC. Interpretation — Original scale development was undocumented. Content validity was questionable, and there was discrepancy between patient and examiner estimates. UCLA appears valuable for measuring change in self-reported physical activity on a group level. 4 out of 5 HA patients and 2 out of 3 KA patients were more physically active 1 year after joint replacement surgery. [ABSTRACT FROM AUTHOR]

Background and purpose — Few studies have reported the mortality rate after skeletal fractures involving different locations, within the same population. We analyzed the 30-day and 1-year mortality rates following different fractures. Patients and methods — We included 295,713 fractures encountered in patients 16–108 years of age, registered in the Swedish Fracture Register (SFR) from 2012 to 2018. Mortality rates were obtained by linkage of the SFR to the Swedish Tax Agency population register. The standardized mortality ratios (SMR) at 30 days and 1 year were calculated for fractures in any location and for each of 27 fracture locations, using age- and sex-life tables from Statistics Sweden (). Results — The overall SMR at 30 days was 6.8 (95% CI 6.7–7.0) and at 1 year 2.2 (CI 2.2–2.2). The SMR was > 2 for 19/27 and 13/27 of the fracture locations at 30 days and 1 year, respectively. Humerus, femur, and tibial diaphysis fractures were all associated with high SMR, at both 30 days and 1 year. Interpretation — Patients sustaining a fracture had approximately a 7-fold increased mortality at 30 days and over 2-fold increased mortality at 1 year as compared with what would be expected in the general population. High mortality rates were seen for patients with axial skeletal and proximal extremity fractures, indicating frailty in these patient groups. [ABSTRACT FROM AUTHOR]

Background and purpose — In Norway all compensation claims based on healthcare services are handled by a government agency (NPE, Norsk Pasientskade Erstatning). We provide an epidemiological overview of claims within pediatric orthopedics in Norway, and identify the most common reasons for claims and compensations. Patients and methods — All compensation claims handled by NPE from 2012 to 2018 within pediatric orthopedics (age 0 to 17 years) were reviewed. Data were analyzed with regard to patient demographics, diagnoses, type of injury, type of treatment, reasons for granted compensation, and total payouts. Results — 487 compensation claims (259 girls, 228 boys) within orthopedic surgery in patients younger than 18 years at time of treatment were identified. Mean age was 12 years (0–17). 150 out of 487 claims (31%) resulted in compensation, including 79 compensations for inadequate treatment, 58 for inadequate diagnostics, 12 for infections, and 1 based on the exceptional rule. Total payouts were US$8.45 million. The most common primary diagnoses were: upper extremity injuries (26%), lower extremity injuries (24%), congenital malformations and deformities (12%), spine deformities (11%), disorders affecting peripheral joints (9%), chondropathies (6%), and others (12%). Interpretation — Most claims were submitted and granted for mismanagement of fractures in the upper and lower extremity, and mismanagement of congenital malformations and disorders of peripheral joints. Knowledge of the details of malpractice claims should be implemented in educational programs and assist pediatric orthopedic surgeons to develop guidelines in order to improve patient safety and quality of care. [ABSTRACT FROM AUTHOR]

Background and purpose — External validation of machine learning (ML) prediction models is an essential step before clinical application. We assessed the proportion, performance, and transparent reporting of externally validated ML prediction models in orthopedic surgery, using the Transparent Reporting for Individual Prognosis or Diagnosis (TRIPOD) guidelines. Material and methods — We performed a systematic search using synonyms for every orthopedic specialty, ML, and external validation. The proportion was determined by using 59 ML prediction models with only internal validation in orthopedic surgical outcome published up until June 18, 2020, previously identified by our group. Model performance was evaluated using discrimination, calibration, and decision-curve analysis. The TRIPOD guidelines assessed transparent reporting. Results — We included 18 studies externally validating 10 different ML prediction models of the 59 available ML models after screening 4,682 studies. All external validations identified in this review retained good discrimination. Other key performance measures were provided in only 3 studies, rendering overall performance evaluation difficult. The overall median TRIPOD completeness was 61% (IQR 43–89), with 6 items being reported in less than 4/18 of the studies. Interpretation — Most current predictive ML models are not externally validated. The 18 available external validation studies were characterized by incomplete reporting of performance measures, limiting a transparent examination of model performance. Further prospective studies are needed to validate or refute the myriad of predictive ML models in orthopedics while adhering to existing guidelines. This ensures clinicians can take full advantage of validated and clinically implementable ML decision tools. [ABSTRACT FROM AUTHOR]

Background and purpose — Proton-pump inhibitors (PPI) have previously been associated with an increased risk of infections such as community-acquired pneumonia, gastrointestinal infections and central nervous system infection. Therefore, we evaluated a possible association between proton-pump inhibitor use and prosthetic joint infection (PJI) in patients with total hip arthroplasty (THA), because they can be stopped perioperatively or switched to a less harmful alternative. Patients and methods — A cohort of 5,512 primary THAs provided the base for a case-cohort design; cases were identified as patients with early-onset PJI. A weighted Cox proportional hazard regression model was used for the study design and to adjust for potential confounders. Results — There were 75 patients diagnosed with PJI of whom 32 (43%) used PPIs perioperatively compared with 75 PPI users (25%) in the control group of 302 patients. The risk of PJI was 2.4 times higher (95% CI 1.4–4.0) for patients using PPI. This effect remained after correction for possible confounders. Interpretation — The use of PPIs was associated with an increased risk of developing PJI after THA. Hence, the use of a PPI appears to be a modifiable risk factor for PJI. [ABSTRACT FROM AUTHOR]

Background and purpose — There is still no consensus on whether to use thromboprophylaxis as a standard treatment in shoulder replacement surgery. We investigated the use of thromboprophylaxis reported to the Norwegian Arthroplasty Register (NAR). The primary endpoint was early mortality after primary shoulder arthroplasty with and without thromboprophylaxis. Secondary endpoints included revisions within 1 year and intraoperative complications. Patients and methods — This observational study included 6,123 primary shoulder arthroplasties in 5,624 patients reported to the NAR from 2005 to 2018. Cox regression analyses including robust variance analysis were performed with adjustments for age, sex, ASA score, diagnosis, type of implant, fixation, duration of surgery, and year of primary surgery. An instrumental variable Cox regression was performed to estimate the causal effect of thromboprophylaxis. Results — Thromboprophylaxis was used in 4,089 out of 6,123 shoulder arthroplasties. 90-day mortality was similar between the thromboprophylaxis and no thromboprophylaxis groups (hazard ratio (HR) = 1.1, 95% CI 0.6–2.4). High age (> 75), high ASA class (≥ 3), and fracture diagnosis increased postoperative mortality. No statistically significant difference in the risk of revision within 1 year could be found (HR = 0.6, CI 0.3–1.2). The proportion of intraoperative bleeding was similar in the 2 groups (0.2%, 0.3%). Interpretation — We had no information on cause of death and relation to thromboembolic events. However, no association of reduced mortality with use of thromboprophylaxis was found. Based on our findings routine use of thromboprophylaxis in shoulder arthroplasty can be questioned. [ABSTRACT FROM AUTHOR]