The multiple myeloma microenvironment is defined by an inflammatory stromal cell landscape.

Progression and persistence of malignancies are influenced by the local tumor microenvironment, and future eradication of currently incurable tumors will, in part, hinge on our understanding of malignant cell biology in the context of their nourishing surroundings. Here, we generated paired single-cell transcriptomic datasets of tumor cells and the bone marrow immune and stromal microenvironment in multiple myeloma. These analyses identified myeloma-specific inflammatory mesenchymal stromal cells, which spatially colocalized with tumor cells and immune cells and transcribed genes involved in tumor survival and immune modulation. Inflammatory stromal cell signatures were driven by stimulation with proinflammatory cytokines, and analyses of immune cell subsets suggested interferon-responsive effector T cell and CD8+ stem cell memory T cell populations as potential sources of stromal cell-activating cytokines. Tracking stromal inflammation in individuals over time revealed that successful antitumor induction therapy is unable to revert bone marrow inflammation, predicting a role for mesenchymal stromal cells in disease persistence.

Higher risk of knee arthroplasty during ten-year follow-up if baseline radiographic osteoarthritis involves the patellofemoral joint: a CHECK Cohort Study.

BACKGROUND: Patellofemoral OA is a strong risk factor for progression to generalized whole knee OA, but it is unknown whether involvement of the patellofemoral joint in early radiographic OA (ROA) is associated with risk of undergoing future knee arthroplasty. This is clinically relevant because patellofemoral OA likely requires a different treatment approach than tibiofemoral OA, and identifying prognostic factors for future arthroplasty might assist clinicians with prioritizing and guiding early interventions that could improve long-term outcomes. Therefore, we evaluated association of baseline patellofemoral or tibiofemoral ROA with undergoing knee arthroplasty over 10 years. METHODS: Using the multicenter Cohort Hip and Cohort Knee (CHECK) study, we acquired three views of radiographs in both knees of individuals aged 45-65 years with complaints of knee symptoms in at least one knee. From baseline radiographs, we categorized each knee as having one of four patterns of ROA: no ROA, isolated patellofemoral ROA, isolated tibiofemoral ROA, or combined ROA. We evaluated the 10-year relative hazard for undergoing going arthroplasty, based on baseline ROA pattern, using Cox proportional hazard models, adjusting for age, sex body mass index, and pain severity. RESULT: Our sample (n = 842) included 671 (80%) women and had mean (SD) age 56 (5) years, and BMI 26.3 (4.0) kg/m2. Arthroplasties were undertaken in 44/1678 knees. In comparison to having no ROA at baseline, adjusted hazard ratios (aHR) for arthroplasty were highest for combined ROA (aHR 14.2 [95% CI 5.8, 34.6]) and isolated patellofemoral ROA (aHR 12.7 [5.6, 29.0]). Isolated tibiofemoral ROA was not significantly associated with arthroplasty (aHR 2.9 [0.6, 13.6]). CONCLUSIONS: In a sample of middle-aged individuals with complaints in one or both knees, the 10-year relative hazard for undergoing arthroplasty, compared to no ROA, was increased when OA involved the patellofemoral joint, regardless of whether it was isolated to the patellofemoral joint or occurred in combination with tibiofemoral OA. Further research is needed to confirm this association and to clarify the causal mechanism of this relationship. However, our results provide preliminary evidence that identifying patellofemoral ROA may be a clinically useful prognostic indicator in early knee OA.

MSC encapsulation in alginate microcapsules prolongs survival after intra-articular injection, a longitudinal in vivo cell and bead integrity tracking study.

Mesenchymal stem cells (MSC) are promising candidates for use as a biological therapeutic. Since locally injected MSC disappear within a few weeks, we hypothesize that efficacy of MSC can be enhanced by prolonging their presence. Previously, encapsulation in alginate was suggested as a suitable approach for this purpose. We found no differences between the two alginate types, alginate high in mannuronic acid (High M) and alginate high in guluronic acid (High G), regarding MSC viability, MSC immunomodulatory capability, or retention of capsule integrity after subcutaneous implantation in immune competent rats. High G proved to be more suitable for production of injectable beads. Firefly luciferase-expressing rat MSC were used to track MSC viability. Encapsulation in high G alginate prolonged the presence of metabolically active allogenic MSC in immune competent rats with monoiodoacetate-induced osteoarthritis for at least 8 weeks. Encapsulation of human MSC for local treatment by intra-articular injection did not significantly influence the effect on pain, synovial inflammation, or cartilage damage in this disease model. MSC encapsulation in alginate allows for an injectable approach which prolongs the presence of viable cells subcutaneously or in an osteoarthritic joint. Further fine tuning of alginate formulation and effective dosage for might be required in order to improve therapeutic efficacy depending on the target disease. Graphical Abstract.

Effectiveness of intramuscular gluteal glucocorticoid injection versus intra-articular glucocorticoid injection in knee osteoarthritis: design of a multicenter randomized, 24 weeks comparative parallel-group trial.

BACKGROUND: The knee is symptomatically the most frequent affected joint in osteoarthritis and, in the Netherlands and other Western countries, is mainly managed by general practitioners (GPs). An intra-articular glucocorticoid injection is recommended in (inter) national guidelines for patients with knee osteoarthritis as an option for a flare of knee pain and/or for those who are not responding well to pain medication. An innovative approach that could replace the intra-articular injection is an intramuscular gluteal glucocorticoid injection. An intramuscular injection is easier to perform than an intra-articular injection with lesser risk of severe local adverse reactions. We hypothesize that intramuscular gluteal glucocorticoid injection is non-inferior in reducing knee pain compared to intra-articular glucocorticoid injection, with potentially a longer lasting effect than intra-articular injection. METHODS/DESIGN: The study will be a pragmatic randomized controlled non-inferiority trial with two parallel groups. A total of 140 patients aged 45 years and older with knee osteoarthritis who contacted their general practitioner and have persistent knee pain (score ≥ 3 on 0-10 numerical rating scale; 0 = no knee pain) will be included. Patients will be randomly allocated (1:1) to an injection of 40 mg triamcinolone acetonide intra-articular in the knee joint or intramuscular in the ipsilateral ventrogluteal area. The effect of treatment will be evaluated by questionnaires at 2, 4, 8, 12, and 24 weeks after injection. The primary outcome is patients' reported severity of knee pain measured with the pain subscale of the Knee injury and Osteoarthritis Outcome Score 4 weeks after injection. Statistical analysis will be based on both the per-protocol and the intention-to-treat principle. DISCUSSION: This study will evaluate non-inferiority of intramuscular glucocorticoid injection compared to intra-articular glucocorticoid injection for knee osteoarthritis symptoms. TRIAL REGISTRATION: This trial is registered in the Dutch Trial Registry (number NTR6968) at 2018-01-22 (https://www.trialregister.nl/trial/6784). Issue date: 1 October 2019. TRIAL SPONSOR: Erasmus MC University Medical Center Rotterdam. PO-box 2040. 3000 CA Rotterdam. The Netherlands.

Hip Arthroplasty Malpractice Claims in the Netherlands: Closed Claim Study 2000-2012.

BACKGROUND: A total hip arthroplasty (THA) is a successful and reliable operation with few complications. These complications however, do form a potential source for compensation claims. In the Netherlands, there are no studies available concerning filed claims after THA. The aim of this study was to determine the incidence of claims related to THAs in the Netherlands and the reasons to claim, which claims lead to compensation, the costs involved for the insurer, and the demographics of the claimants. METHODS: In this observational study, we analyzed all closed claims from 2000 to 2012 from the national largest insurer of medical liability and compared it to data from our national implant registry in the Netherlands. With the intention to contribute to prevention, we have identified the demographics of the claimant, the reasons for filing claims, and the outcome of claims. RESULTS: Overall, 516 claims were expressed in 280 closed claim files after THA. Claims were most often related to sciatic nerve injury (19.6%). Most claimants were women (71.6%) with an average age of 63.1 years. The median cost per compensated claim is €5.921. CONCLUSION: The claimant is more likely to be female and to be younger than the average patient receiving a THA. The incidence of a claim after a THA is 0.14%-0.30%. Nerve damage is the most common reason to file for compensation. The distribution in reasons to claim does not resemble the complication rate in literature after a THA. The outcome of this study can be used to improve patient care, safety, and costs.

"Atypical" atypical femur fractures and use of bisphosphonates.

BACKGROUND: Atypical femur fractures (AFFs) present a rare but serious condition associated with use of bisphosphonates. Underlying mechanisms and clinical risk factors remain unclear. According to the diagnostic criteria formulated by the ASBMR, a lateral localization of an AFF is required. CASE HISTORY: We present a patient who developed bilateral leg pain while using an oral bisphosphonate and aromatase inhibitor in the course of adjuvant treatment for breast cancer. Initially she was diagnosed with bone metastases and received radiotherapy on the right femur. However, the bilateral periosteal reactions of the subtrochanteric femur are highly suggestive of AFFs. Our case meets all criteria for AFF except that she presented with lesions at the medial side of the femur. Therefore they could be best described as "atypical" atypical femur fractures. DISCUSSION: Since the pathogenesis of AFFs is not fully understood, we cannot rule out that AFFs also occur in the medial femur or in other weight-baring bones. Hence we propose that medial stress reactions belong to a spectrum of atypical fractures associated with use of antiresorptive drugs. The localization may depend on yet unknown biomechanical factors. CONCLUSION: We propose that these periosteal reactions of the subtrochanteric femur are in fact AFFs with uncommon medial localization and could hence be considered "atypical" AFFs. We recommend being alert of AFFs in patients with bone pain and medial subtrochanteric lesions. More epidemiological studies are needed to investigate the occurrence of both medial and lateral AFFs and to gain more insight into its frequency and pathogenesis.

Do laterally wedged insoles or valgus braces unload the medial compartment of the knee in patients with osteoarthritis?

BACKGROUND: The results of conservative treatment of knee osteoarthritis (OA) are generally evaluated in epidemiological studies with clinical outcome measures as primary outcomes. Biomechanical evaluation of orthoses shows that there are potentially beneficial biomechanical changes to joint loading; however, evaluation in relation to clinical outcome measures in longitudinal studies is needed. QUESTIONS/PURPOSES: We asked (1) is there an immediate effect on gait in patients using a laterally wedged insole or valgus knee brace; (2) is there a late (6 weeks) effect; and (3) is there a difference between subgroups within each group with respect to patient compliance, body mass index, and OA status? METHODS: This was a secondary analysis of data from a previous randomized controlled trial of patients with early medial knee OA. A total of 91 patients were enrolled in that trial, and 73 (80%) completed it after 6 months. Of the enrolled patients, 80 (88%) met prespecified inclusion criteria for analysis in the present study. The patients were randomized to an insole or brace. Gait was analyzed with and without wearing the orthosis (insole or brace) at baseline and after 6 weeks. Measurements were taken of the knee adduction moment, ground reaction force, moment arm, walking speed, and toe-out angle. Data were analyzed with regression analyses based on an intention-to-treat principle. RESULTS: A mean reduction of 4% (±10) (95% confidence interval [CI], -0.147 to -0.03, p=0.003) of the peak knee adduction moment and 4% (±13) (95% CI, -0.009 to -0.001, p=0.01) of the moment arm at baseline was observed in the insole group when walking with an insole was compared with walking without an insole. A mean reduction of 1% (±10) (95% CI, -0.002 to -0.001, p=0.001) of the peak knee adduction moment and no reduction of the moment arm were measured after 6 weeks. No reduction of knee adduction moment, moment arm, or ground reaction force was seen in the brace group at baseline and after 6 weeks. Subgroup analysis showed no differences in biomechanical effect for obesity, stage of OA, and whether patients showed a clinical response to the treatment. CONCLUSIONS: Laterally wedged insoles unload the medial compartment only at baseline in patients with varus alignment and by an amount that might not be clinically important. No biomechanical alteration was seen after 6 weeks of wearing the insole. Valgus brace therapy did not result in any biomechanical alteration. Taken together, this study does not show a clinically relevant biomechanical effect of insole and brace therapy in patients with varus medial knee OA. LEVEL OF EVIDENCE: Level I, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

HUMeral shaft fractures: measuring recovery after operative versus non-operative treatment (HUMMER): a multicenter comparative observational study.

BACKGROUND: Fractures of the humeral shaft are associated with a profound temporary (and in the elderly sometimes even permanent) impairment of independence and quality of life. These fractures can be treated operatively or non-operatively, but the optimal tailored treatment is an unresolved problem. As no high-quality comparative randomized or observational studies are available, a recent Cochrane review concluded there is no evidence of sufficient scientific quality available to inform the decision to operate or not. Since randomized controlled trials for this injury have shown feasibility issues, this study is designed to provide the best achievable evidence to answer this unresolved problem. The primary aim of this study is to evaluate functional recovery after operative versus non-operative treatment in adult patients who sustained a humeral shaft fracture. Secondary aims include the effect of treatment on pain, complications, generic health-related quality of life, time to resumption of activities of daily living and work, and cost-effectiveness. The main hypothesis is that operative treatment will result in faster recovery. METHODS/DESIGN: The design of the study will be a multicenter prospective observational study of 400 patients who have sustained a humeral shaft fracture, AO type 12A or 12B. Treatment decision (i.e., operative or non-operative) will be left to the discretion of the treating surgeon. Critical elements of treatment will be registered and outcome will be monitored at regular intervals over the subsequent 12 months. The primary outcome measure is the Disabilities of the Arm, Shoulder, and Hand score. Secondary outcome measures are the Constant score, pain level at both sides, range of motion of the elbow and shoulder joint at both sides, radiographic healing, rate of complications and (secondary) interventions, health-related quality of life (Short-Form 36 and EuroQol-5D), time to resumption of ADL/work, and cost-effectiveness. Data will be analyzed using univariate and multivariable analyses (including mixed effects regression analysis). The cost-effectiveness analysis will be performed from a societal perspective. DISCUSSION: Successful completion of this trial will provide evidence on the effectiveness of operative versus non-operative treatment of patients with a humeral shaft fracture. TRIAL REGISTRATION: The trial is registered at the Netherlands Trial Register (NTR3617).

Evaluating the Clinical Relevance of Routine Sonication for Periprosthetic Hip or Knee Joint Infection Diagnosis.

Periprosthetic joint infection (PJI) is a serious complication after joint arthroplasty. PJI screening and conventional cultures may be inconclusive. Sonication fluid culturing stands out as a valuable adjunct technique for PJI diagnosis. This study aims to determine the clinical relevance of routine sonication for all (a)septic revisions. All patients who underwent (partial) hip or knee revision arthroplasty between 2012 and 2021 were retrospectively reviewed. We formed three groups based on the European Bone and Joint Society PJI criteria: infection confirmed, likely, and unlikely. We analyzed clinical, laboratory, and radiological screening. Sensitivity and specificity were calculated for synovial fluid (preoperative), tissue, and sonication fluid cultures. We determined the clinical relevance of sonication as the percentage of patients for whom sonication confirmed PJI; 429 patients who underwent (partial) revision of hip or knee arthroplasty were included. Sensitivity and specificity were 69% and 99% for synovial fluid cultures, 76% and 92% for tissue cultures, and 80% and 89% for sonication fluid cultures, respectively. Sonication fluid cultures improved tissue culture sensitivity and specificity to 83% and 99%, respectively. In 11% of PJIs, sonication fluid cultures were decisive for diagnosis. This is applicable to acute and chronic infections. Sonication fluid cultures enhanced the sensitivity and specificity of PJI diagnostics. In 11% of PJI cases, causative pathogens were confirmed by sonication fluid culture results. Sonication fluid culture should be performed in all revision arthroplasties.

Femoral Neck Design Does Not Impact Revision Risk After Primary Total Hip Arthroplasty Using a Dual Mobility Cup.

Background: The use of dual mobility (DM) cups has increased quickly. It is hypothesized that femoral neck taper geometry may be involved in the risk of prosthetic impingement and DM cup revision. We aim to (1) explore the reasons for revision of DM cups or head/liners and (2) explore whether certain femoral neck characteristics are associated with a higher risk of revision of DM cups. Methods: Primary total hip arthroplasties with a DM cup registered in the Dutch Arthroplasty Register between 2007 and 2021 were identified (n = 7603). Competing risk survival analyses were performed, with acetabular component and head/liner revision as the primary endpoint. Reasons for revision were categorized in cup-/liner-related revisions (dislocation, liner wear, acetabular loosening). Femoral neck characteristics were studied to assess whether there is an association between femoral neck design and the risk of DM cup/liner revision. Multivariable Cox proportional hazard analyses were performed. Results: The 5- and 10-year crude cumulative incidence of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was 0.5% (CI 0.4-0.8) and 1.9% (CI 1.3-2.8), respectively. After adjusting for confounders, we found no association between the examined femoral neck characteristics (alloy used, neck geometry, CCD angle, and surface roughness) and the risk for revision for dislocation, wear, and acetabular loosening. Conclusions: The risk of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was low. We found no evidence that there is an association between femoral neck design and the risk of cup or head/liner revision.

Effect of Intramuscular vs Intra-articular Glucocorticoid Injection on Pain Among Adults With Knee Osteoarthritis: The KIS Randomized Clinical Trial.

Importance: Intra-articular (IA) glucocorticoid injection is widely used in patients with knee osteoarthritis (OA), but the safety of this technique is in question among physicians. Intramuscular (IM) glucocorticoid injection could be an alternative approach. Objective: To investigate whether an IM glucocorticoid injection is noninferior to an IA glucocorticoid injection in reducing knee pain for patients with knee OA in primary care. Design, Setting, and Participants: The KIS trial, a multicenter, open-label, randomized clinical noninferiority trial including patients with symptomatic knee OA, was conducted in 80 primary care general practices in the southwest of the Netherlands. The study was conducted from March 1, 2018, to July 28, 2020. Interventions: Patients were randomly allocated to receive an injection of triamcinolone acetonide, 40 mg, either IM in the ipsilateral ventrogluteal region or IA in the knee joint. All patients were followed up for 24 weeks. Main Outcomes and Measures: The pain score at 4 weeks measured with Knee Injury and Osteoarthritis Outcome Score (range, 0-100; 0 indicates extreme pain), with a noninferiority margin of -7 (IM minus IA). A per-protocol analysis was prespecified as the primary analysis. Results: A total of 145 patients (94 women [65%]; mean [SD] age, 67 [10] years) were included; of these, 138 patients (IM, 72; IA, 66) were included in the per-protocol analysis. Clinically relevant improvements in knee pain were reached up to 12 weeks after the injection in both groups. At 4 weeks, the estimated mean difference in the Knee Injury and Osteoarthritis Outcome Score between the 2 groups was -3.4 (95% CI, -10.1 to 3.3). Noninferiority could not be declared because the lower limit exceeded the noninferiority margin. Intramuscular injection was noninferior to IA injection at 8 (mean difference, 0.7; 95% CI, -6.5 to 7.8) and 24 (mean difference, 1.6; 95% CI, -5.7 to 9.0) weeks. No significant difference was found among all the secondary outcomes. These results were similar for the sensitivity analysis in an intention-to-treat population. The most frequently reported adverse events were hot flush (IM, 7 [10%] vs IA, 14 [21%]) and headache (IM, 10 [14%] vs IA, 12 [18%]), and all events were classified as nonserious. Conclusions and Relevance: Based on the findings of this trial, among patients with knee OA in primary care, IM glucocorticoid injection could present an inferior effect in reducing pain at 4 weeks compared with IA injection. Noninferiority of an IM injection was observed at 8 and 24 weeks after injection. This trial provides data for shared decision-making, taking into account the advantages and disadvantages of both types of injections. Trial Registration: Dutch Trial Registry: NTR6968.

Accelerated menopausal changes as human disease model 'FOCUM' for the development of osteoarthritis and other degenerative disorders: protocol for a prospective cohort study.

INTRODUCTION: The incidence of degenerative disorders, including osteoarthritis (OA), increases rapidly in women after menopause. However, the influence of the menopause is still insufficiently investigated due to the slowness of menopausal transition. In this study, a novel human model is used in which it is expected that menopausal-related changes will occur faster. This is the Females discontinuing Oral Contraceptives Use at Menopausal age model. The ultimate aim is to link these changes to OA and other degenerative disorders, including cardiovascular diseases, diabetes, osteoporosis and tendinopathies. METHODS AND ANALYSIS: This is a pilot observational prospective cohort study with 2 years of follow-up. Fifty women aged 50-60 who use oral contraceptive (OC) and have the intention to stop are included. Measurements are performed once before stopping OC, and four times thereafter at 6 weeks, 6 months, 1 year and 2 years. At every time point, a questionnaire is filled in and a sample of blood is drawn. At the first and final time points, a physical examination, hand radiographs and a MRI scan of one knee are performed. The primary OA outcome is progression of the MRI Osteoarthritis Knee Score. Secondary OA outcomes are the development of clinical knee and hand OA, development of knee OA according to the MRI definition, and progression of radiographic features for hand OA. Principal component analysis will be used to assess which changes occur after stopping OC. Univariate and multivariate generalised estimating equation models will be used to test for associations between these components and OA. ETHICS AND DISSEMINATION: The study has been approved by the Medical Ethics Committee of the Erasmus MC University Medical Center Rotterdam (MEC-2019-0592). All participants must give informed consent before data collection. Results will be disseminated in national and international journals. TRIAL REGISTRATION NUMBER: NL70796.078.19.

Effectiveness of intramuscular corticosteroid injection versus placebo injection in patients with hip osteoarthritis: design of a randomized double-blinded controlled trial.

BACKGROUND: Recent international guidelines recommend intra-articular corticosteroid injections for patients with hip osteoarthritis who have moderate to severe pain and do not respond satisfactorily to oral analgesic/anti-inflammatory agents. Of the five available randomized controlled trials, four showed positive effects with respect to pain reduction. However, intra-articular injection in the hip is complex because the joint is adjacent to important neurovascular structures and cannot be palpated. Therefore fluoroscopic or ultrasound guidance is needed.The systemic effect of corticosteroids has been studied in patients with impingement shoulder pain. Gluteal corticosteroid injection was almost as effective as ultrasound-guided subacromial corticosteroid injection. Such a clinically relevant effect of a systemic corticosteroid injection offers a less complex alternative for treatment of patients with hip osteoarthritis not responsive to oral pain medication. METHODS/DESIGN: This is a double-blinded, randomized controlled trial. A total of 135 patients (aged > 40 years) with hip osteoarthritis and persistent pain despite oral analgesics visiting a general practitioner or orthopaedic surgeon will be included. They will be randomized to a gluteal intramuscular corticosteroid injection or a gluteal intramuscular placebo (saline) injection. The randomization will be stratified for setting (general practitioner and outpatient clinics of department of orthopaedics). Treatment effect will be evaluated by questionnaires at 2, 4, 6, and 12 weeks follow-up and a physical examination at 12 weeks. Primary outcome is severity of hip pain reported by the patients at 2-week follow-up. Statistical analyses will be based on the intention-to-treat principle. DISCUSSION: This study will evaluate the effectiveness of an intramuscular corticosteroid injection on pain in patients with hip osteoarthritis. Patient recruitment has started. TRIAL REGISTRATION: This trial is registered in the Dutch Trial Registry: number NTR2966.

Facial subcutaneous emphysema due to rectum injury after pelvic fracture.

A 35-year old dockworker sustained a pelvic injury when he was caught by a large loading clamshell grab. Primary survey revealed an open book pelvic fracture with soft tissue defects of the left thigh and groin. CT scanning of the thorax and abdomen did not reveal significant additional injuries. Partly due to patient's haemodynamical instability, osteosynthesis of the pelvic fracture was performed immediately after resuscitation, whereby the severely contaminated wound of the thigh was debrided and irrigated. The following days, progressive facial subcutaneous emphysema developed, but patient remained clinically stable. Several specialists were consulted, but did not find a cause. At day 7, a second surgery was planned to treat a pelvic surgical wound infection. Unexpectedly, we found faecal contamination in the pelvic surgical wound. The consulted gastro/intestinal-surgeon performed a laparoscopic colostomy for a rectal laceration. Awareness for bowel injuries with open pelvic fracture should be high, also when subcutaneous emphysema is found remotely.

Timing of debridement, antibiotics, and implant retention (DAIR) for early post-surgical hip and knee prosthetic joint infection (PJI) does not affect 1-year re-revision rates: data from the Dutch Arthroplasty Register.

Debridement, antibiotics, and implant retention (DAIR) is a procedure to treat a periprosthetic joint infection (PJI) after total hip arthroplasty (THA) or total knee arthroplasty (TKA). The timing between the primary procedure and the DAIR is likely a determinant for its successful outcome. However, the optimal timing of a DAIR and the chance of success still remain unclear. We aimed to assess the risk of re-revision within 1 year after a DAIR procedure and to evaluate the timing of the DAIR in primary THA and TKA. We used data from the Dutch Arthroplasty Register (LROI) and selected all primary THA and TKA in the period 2007-2016 which underwent a DAIR within 12 weeks after primary procedure. A DAIR was defined as a revision for infection in which only modular parts were exchanged. A DAIR was defined as successful if not followed by a re-revision within 1 year after DAIR; 207 DAIRs were performed < 4  weeks after THA, of which 16 (8 %) received a complete revision within 1 year. DAIR procedures performed between 4 and 12 weeks ( n = 98 ) had a failure rate of 9 % ( n = 9 ). After TKA 126 DAIRs were performed in less than 4  weeks, of which 11 (9 %) received a complete revision within 1 year; 83 DAIRs were performed between 4 and 12 weeks, of which 14 (17 %) were revised. There was no significant difference in 1-year re-revision rate after a DAIR procedure by timing of the DAIR procedure for total hip and knee arthroplasty based on Dutch registry data.

Preoperative embolization in surgical treatment of long bone metastasis: a systematic literature review.

Surgery of long bone metastases is associated with a significant risk of perioperative blood loss, which may necessitate blood transfusion.Successful embolization (> 70% obliteration of vascularity) can be achieved in 36-75% of cases.The reported rate of embolization-related complications is 0-9%.Three out of six level III evidence studies showed a reduction in perioperative blood loss and/or blood transfusion requirement after preoperative embolization of renal cell carcinoma metastasis in long bones; three out of six studies did not.One level III evidence study did not show a reduction in perioperative blood loss and/or transfusion requirement after preoperative embolization of hepatocellular carcinoma metastases in long bones.There were no studies found that support preoperative embolization of thyroid metastases or other frequent long bone metastases (e.g. mamma carcinoma, lung carcinoma, or prostate carcinoma).The clinical level of evidence of the studies found is low and randomized studies taking into account primary tumour, location of metastases and type of surgery are therefore desired. Cite this article: EFORT Open Rev 2020;5:17-25. DOI: 10.1302/2058-5241.5.190013.

Self-Assessment of Competence and Referral Behavior for Musculoskeletal Injections among Dutch General Practitioners.

General practitioners (GPs) are qualified and trained to administer therapeutic musculoskeletal injections when indicated. However, it is unknown to what extend Dutch GPs feel competent to administer these injections in clinical practice. Reluctance among GPs to inject might lead to unnecessary and costly referral to secondary care. An online and offline questionnaire was spread among Dutch GPs, querying demographics, GPs' self-assessment of injection competence, the number of administered/referred injections and management strategy for musculoskeletal injections. A total of 355 GPs responded. In total, 81% of the GPs considered themselves competent in administering musculoskeletal injections. Self-assessed incompetent GPs performed less injections the last month than self-assessed competent GPs (1.2 ± 1.4 vs 4.8 ± 4.6 injections, P < 0.001). Additionally, they referred four times more often to a colleague GP (0.4 ± 1.0 vs 0.1 ± 0.6 injections per month, P < 0.001) and twice as often to secondary care (1.0 ± 1.3 vs 0.5 ± 0.9 injections per month, P = 0.001). Self-assessed incompetence was associated with female sex (OR [95% CI] = 4.94 [2.39, 10.21]) and part-time work (OR [95% CI] = 2.58 [1.43, 4.66]). The most frequently addressed barriers were a lack of confidence in injection skills, lack of practical training, and uncertainty about the effectiveness and diagnosis of musculoskeletal injections. Although most GPs considered themselves competent to administer musculoskeletal injections, the referral rate to secondary care for several injections was strikingly high. To decrease secondary care referrals, addressing some of the most frequently indicated barriers is highly recommended.

Intra-articular Injections of Platelet-Rich Plasma Releasate Reduce Pain and Synovial Inflammation in a Mouse Model of Osteoarthritis.

BACKGROUND: Osteoarthritis (OA) is a degenerative joint disease leading to pain and disability for which no curative treatment exists. A promising biological treatment for OA is intra-articular administration of platelet-rich plasma (PRP). PRP injections in OA joints can relieve pain, although the exact working mechanism is unclear. PURPOSE: To examine the effects of PRP releasate (PRPr) on pain, cartilage damage, and synovial inflammation in a mouse OA model. STUDY DESIGN: Controlled laboratory study. METHODS: OA was induced unilaterally in the knees of male mice (n = 36) by 2 intra-articular injections of collagenase at days -7 and -5. At day 0, pain was measured by registering weight distribution on the hindlimbs, after which mice were randomly divided into 2 groups. Mice received 3 intra-articular injections of PRP or saline in the affected knee. Seven mice per group were euthanized at day 5 for assessment of early synovial inflammation and cartilage damage. Pain in the remaining mice was registered for a total of 3 weeks. These mice were euthanized at day 21 for assessment of cartilage damage and synovial inflammation on histological evaluation. Antibodies against iNOS, CD163, and CD206 were used to identify different subtypes of macrophages in the synovial membrane. RESULTS: Mice in the PRPr group increased the distribution of weight on the affected joint in 2 consecutive weeks after the start of the treatment ( P < .05), whereas mice in the saline group did not. At day 21, PRPr-injected knees had a thinner synovial membrane ( P < .05) and a trend toward less cartilage damage in the lateral joint compartment ( P = .053) than saline-injected knees. OA knees treated with saline showed less anti-inflammatory (CD206+ and CD163+) cells at day 5 than healthy knees, an observation that was not made in the PRPr-treated group. A higher level of pain at day 7 was associated with a thicker synovial membrane at day 21. The presence of CD206+ cells was negatively associated with synovial membrane thickness. CONCLUSION: In a murine OA model, multiple PRPr injections reduced pain and synovial thickness, possibly through modulation of macrophage subtypes. CLINICAL RELEVANCE: PRPr injections in early OA or shortly after joint trauma can reduce pain and synovial inflammation and may inhibit OA development in patients.

Short-duration enzymatic treatment promotes integration of a cartilage graft in a defect.

OBJECTIVES: Surgical manipulation of cartilage tissue is associated with chondrocyte death in the wound edges that hinders integration. The objective of this study was to evaluate the effect of a short course of treatment of a cartilage graft with a combination of hyaluronidase and collagenase on chondrocyte density and integrative capacity. METHODS: Cartilage explants were treated with enzymes for various time periods and at various concentrations. A central core was punched out of a larger explant, treated with enzymes, reimplanted, and placed subcutaneously in athymic mice. The number of chondrocytes in the wound edges was counted, and the integrative capacity of the grafts was evaluated by histology. RESULTS: Treatment with collagenase for 48 hours led to a significant increase in the number of vital chondrocytes and restored it to normal after 14 days of culture. Treatment with hyaluronidase and collagenase for 48 hours further increased chondrocyte densities to supranormal values. Shortening the treatment to 1 hour restored the chondrocyte density to normal after 14 days of culture. In vivo integration experiments showed increased chondrocyte densities in treated wound edges and extracellular matrix fibers crossing over from enzyme-treated parts to untreated parts. CONCLUSIONS: Short-duration treatment of a cartilage graft with a combination of hyaluronidase and collagenase increases cell density at wound edges and promotes integrative repair.

Chondrogenesis of mesenchymal stem cells in an osteochondral environment is mediated by the subchondral bone.

In articular cartilage repair, cells that will be responsible for the formation of repair tissue are often exposed to an osteochondral environment. To study cartilage repair mechanisms in vitro, we have recently developed a bovine osteochondral biopsy culture model in which cartilage defects can be simulated reproducibly. Using this model, we now aimed at studying the chondrogenic potential of human bone marrow-derived mesenchymal stem cells (hBMSCs) in an osteochondral environment. In contrast to standard in vitro chondrogenesis, it was found that supplementing transforming growth factor beta (TGFß) to culture medium was not required to induce chondrogenesis of hBMSCs in an osteochondral environment. hBMSC culture in defects created in osteochondral biopsies or in bone-only biopsies resulted in comparable levels of cartilage-related gene expression, whereas culture in cartilage-only biopsies did not induce chondrogenesis. Subcutaneous implantation in nude mice of osteochondral biopsies containing hBMSCs in osteochondral defects resulted in the formation of more cartilaginous tissue than hBMSCs in chondral defects. The subchondral bone secreted TGFß; however, the observed results could not be attributed to TGFß, as either capturing TGFß with an antibody or blocking the canonical TGFß signaling pathway did not result in significant changes in cartilage-related gene expression of hBMSCs in the osteochondral culture model. Inhibition of BMP signaling did not prevent chondrogenesis. In conclusion, we demonstrate that chondrogenesis of hBMSCs is induced by factors secreted from the bone. We have strong indications that this is not solely mediated by members of the TGFß family but other, yet unknown, factors originating from the subchondral bone appeared to play a key role.