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Surgical robots are increasingly important in orthopedic surgeries to assist or replace surgeons in completing operations. During joint surgeries, the patient's joint needs to be adjusted several times by the surgeon. Therefore, the virtual model, built on the preoperative medical images, cannot match the actual variation of the patient's joint during the surgery. Conventional virtual reality techniques cannot fully satisfy the requirements of the joint surgeries. This paper proposes a real and virtual bidirectional driving method to synchronize the manipulations in both the real operation site and the virtual scene. The dynamic digital twin of the patient's joint is obtained by decoupling the joint and dynamically updating its pose via the intraoperative measurements. During surgery, the surgeon can intuitively monitor the real-time position of the patient and the surgical tool through the system and can also manipulate the surgical robot in the virtual scene. In addition, the system can provide visual guidance to the surgeon when the patient's joint is adjusted. A prototype system is developed for orthopedic surgeries. Proof-of-concept joint surgery demo is carried out to verify the effectiveness of the proposed method. Experimental results show that the proposed system can synchronize the manipulations in both the real operation site and the virtual scene, thus realizing the bidirectional driving. [ABSTRACT FROM AUTHOR]

Surgical robots are increasingly important in orthopedic surgeries to assist or replace surgeons in completing operations. During joint surgeries, the patient’s joint needs to be adjusted several times by the surgeon. Therefore, the virtual model, built on the preoperative medical images, cannot match the actual variation of the patient’s joint during the surgery. Conventional virtual reality techniques cannot fully satisfy the requirements of the joint surgeries. This paper proposes a real and virtual bidirectional driving method to synchronize the manipulations in both the real operation site and the virtual scene. The dynamic digital twin of the patient’s joint is obtained by decoupling the joint and dynamically updating its pose via the intraoperative measurements. During surgery, the surgeon can intuitively monitor the real-time position of the patient and the surgical tool through the system and can also manipulate the surgical robot in the virtual scene. In addition, the system can provide visual guidance to the surgeon when the patient’s joint is adjusted. A prototype system is developed for orthopedic surgeries. Proof-of-concept joint surgery demo is carried out to verify the effectiveness of the proposed method. Experimental results show that the proposed system can synchronize the manipulations in both the real operation site and the virtual scene, thus realizing the bidirectional driving.

The spleen plays a role in innate and adaptive immunity, and autoimmune diseases like rheumatoid arthritis (RA). We investigated the effect of splenectomy in early and moderate stages of autoimmune arthritis in a mouse model. To induce recombinant human G1-induced arthritis (GIA), BALB/c mice were immunized intraperitoneally three times in 4-week intervals with the rhG1 antigen. Mice were splenectomized on day 7 (SPE1) or day 35 (SPE2) after the initiation of immunization; tested for clinical severity, joint radiological and histological changes, serum levels of inflammatory cytokines and autoantibodies, and rhG1-specific immune responses; and compared to those in control mice with spleen left intact. Circulating Tregs and T-helper subset ratios in the spleen and inguinal lymph nodes (LNs) were also examined using flow cytometry. The onset of severe inflammatory response was significantly delayed in SPE1 and SPE2 groups compared to control mice at early stages of GIA, which was associated with increased circulating Tregs. After the third immunization, as disease progressed, the severity scores were robustly increased in all mice. Nevertheless, in splenectomized mice, we observed reduced joint deterioration and cartilage damage, more Th2 cells in LNs, and reduced levels of pro-inflammatory cytokines and autoantibodies in their sera. Mesenteric LN cells of splenectomized mice exhibited weaker response in vitro against the rhG1 antigen compared to control mice spleen. In conclusion, splenectomy in the early stages of GIA delayed the inflammatory response, suggesting a protective effect against the development and progression of severe destructive arthritis., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology.)

Irrespective of the exceptional adaptation of dromedaries to harsh environmental conditions, they remain highly susceptible to joint lameness resulting from a range of diverse factors and conditions. The joints most often affected by traumatic osteoarthritis in dromedaries are the metacarpophalangeal and metatarsophalangeal joints. A comprehensive understanding of joint anatomy and topography of the dromedary is required to perform arthrocentesis correctly on affected joints. Forty-two distal limbs were taken from 28 camels and studied by gross dissection, casting, ultrasonography, and computed tomography (CT). Representative three-dimensional models of the joint cavities, recesses, and pouches were obtained using different casting agents. This study provides a detailed description of dorsally, axially, and abaxially positioned joint recesses, as well as palmar/plantar positioned joint pouches. The safety and feasibility of the different arthrocentesis approaches were evaluated. The traditional dorsal arthrocentesis approach of the metacarpophalangeal, metatarsophalangeal, proximal interphalangeal, and distal interphalangeal joints, has limitations due to the risk of damaging the tendon structures and articular cartilage, which can lead to joint degeneration. A lateral arthrocentesis approach via the proximal palmar/plantar pouches of the metacarpophalangeal/metatarsophalangeal and proximal interphalangeal joints is recommended. This approach eliminates the potential needle injury to the articulating joint cartilage and other surrounding joint structures, such as tendons, blood vessels, and nerves., (© 2023. Springer Nature Limited.)

Objective: To report arthroscopic osteochondral fragment removal from the equine cervical spine articular process joints (APJs) including long-term follow-up., Study Design: Case series., Animals: Three Warmblood horses with forelimb lameness and/or reduced range of motion of the cervical spine with osteochondral fragments between the cervical vertebrae C 5 /C 6 or C 6 /C 7 ., Method: Arthroscopy of the APJs of C 5 /C 6 and C 6 /C 7 was performed under general anesthesia. Following endoscopic evaluation of the joints, osteochondral fragments were removed using a rongeur., Results: All horses recovered from anesthesia with no anesthetic or minor postanesthetic complications. One horse needed a second procedure for fragment removal. Fourteen to 31 months post-surgery the horses were sound for their intended use and neurological examination revealed no abnormalities., Conclusion: Arthroscopic removal of osteochondral fragments can be performed safely in the equine cervical APJs of C 5 /C 6 and C 6 /C 7 resulting in a favorable long-term outcome., Clinical Significance: Arthroscopic removal is a valid option for horses showing clinical signs that can be attributed to osteochondral fragments in the APJs of the neck., (© 2021 The Authors. Veterinary Surgery published by Wiley Periodicals LLC on behalf of American College of Veterinary Surgeons.)

Background: As the demand for total hip arthroplasty (THA) rises, a predictive model for THA risk may aid patients and clinicians in augmenting shared decision-making. We aimed to develop and validate a model predicting THA within 10 years in patients using demographic, clinical, and deep learning (DL)-automated radiographic measurements., Methods: Patients enrolled in the osteoarthritis initiative were included. DL algorithms measuring osteoarthritis- and dysplasia-relevant parameters on baseline pelvis radiographs were developed. Demographic, clinical, and radiographic measurement variables were then used to train generalized additive models to predict THA within 10 years from baseline. A total of 4,796 patients were included [9,592 hips; 58% female; 230 THAs (2.4%)]. Model performance using 1) baseline demographic and clinical variables 2) radiographic variables, and 3) all variables was compared., Results: Using 110 demographic and clinical variables, the model had a baseline area under the receiver operating curve (AUROC) of 0.68 and area under the precision recall curve (AUPRC) of 0.08. Using 26 DL-automated hip measurements, the AUROC was 0.77 and AUPRC was 0.22. Combining all variables, the model improved to an AUROC of 0.81 and AUPRC of 0.28. Three of the top five predictive features in the combined model were radiographic variables, including minimum joint space, along with hip pain and analgesic use. Partial dependency plots revealed predictive discontinuities for radiographic measurements consistent with literature thresholds of osteoarthritis progression and hip dysplasia., Conclusion: A machine learning model predicting 10-year THA performed more accurately with DL radiographic measurements. The model weighted predictive variables in concordance with clinical THA pathology assessments., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Competing Interests: The author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request.

Objectives: The aim of this study was to compare the approximate center of rotation in normal and diseased elbows in dogs., Study Design: Cross-sectional study SAMPLE POPULATION: Computer tomography scans of nine dogs with unilateral fragmented medial coronoid process (FMCP)., Methods: A board certified radiologist confirmed that each dog had unilateral FMCP, and a normal contralateral elbow. Digital 3D models of all elbow joints were uploaded into a surgical planning software package. Four axes approximating the center of rotation (COR) of elbow joints were generated using five geometric shapes based on subchondral topography of the humeral condyle radius and ulna. Images showing the locations where axes exited the medial and lateral cortex of the humeral condyle were captured and imported into a second software package, for measurement of distances between exit points and the origin of a system of axes., Results: In normal joints 20/27 (74%) axes exited the medial cortex, and 25/27 (93%) axes exited the lateral cortex cranial and distal to the medial and lateral epicondyles, respectively. In diseased joints 22/27 (81%) axes exited medial cortex and 19/27 (70%) axes exited the lateral cortex, caudal and distal to the medial and lateral epicondyles, respectively., Conclusion: Based on CT- derived geometry, the COR of elbow affected with FMCP was generally more caudal than normal., Clinical Significance: External landmarks approximating the location of the elbow COR are provided, and while not validated, may assist in planning, creation, and assessment of procedures for FMCP., (© 2022 American College of Veterinary Surgeons.)

Objective: This report evaluates the use of 4.5- and 5.5-mm cannulated drill bits for articular cartilage removal from the proximal interphalangeal joints of equine cadaver limbs., Animals: Limbs from 8 equine cadavers, all with normal proximal interphalangeal joints., Procedure: Proximal interphalangeal joints of 32 limbs from 8 equine cadavers were drilled using either 4.5- or 5.5-mm cannulated drill bits. Pastern joints were then disarticulated, and intra-articular drilling was evaluated by visual inspection., Results: Post-drilling evaluation revealed complete intra-articular drilling occurred in all 32 joints., Conclusion: Canulated 4.5- and 5.5-mm drill bits resulted in consistent accurate intra-articular drilling in the proximal interphalangeal joint of horses., Clinical Relevance: Cannulated drill bits provided an effective and consistent modality for articular cartilage removal with potential for improved accuracy of articular drilling and applications in minimally invasive proximal interphalangeal joint arthrodesis., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

This study aimed to examine the progression of large joint involvement from early to established RA in terms of range of movement (ROM) and time to joint surgery, according to the presence of rheumatoid factor (RF). We used a historical longitudinal cohort of early RA patients. Patients were deemed RF negative if all repeated assessments were negative. The rate of progression from normal to any loss of range of movement (ROM) from years 3 to 14 were modelled using generalized estimating equations, for elbows, wrists, hips, knees and ankle, adjusting for confounders. Time to joint surgery was analysed using multivariable Cox models. A total of 1458 patients were included (66% female, mean age 55 years) and 74% were RF-positive. The prevalence of any loss of ROM, from year 3 through to 14 was highest in the wrist followed by ankle, knee, elbow and hip. Odds of loss of ROM increased over time in all joint regions assessed, at around 7-13% per year from year 3 to 14. Time to surgery was similar according to RF-status for the wrist and ankle, but RF-positive cases had a lower hazard of surgery at the elbow (HR 0.37, 0.15-0.90), hip (HR 0.69, 0.48-0.99) and after 10 years at the knee (HR 0.41, 0.25-0.68). Large joints become progressively involved in RA, most frequently affecting the wrist followed by ankle, which is overlooked in composite disease activity indices. RF-negative and positive cases progressed similarly. Treat-to-target approaches should be followed irrespective of RF status., (© 2021. The Author(s).)

Prosthetic joint infection (PJI) is a feared and challenging to diagnose complication after arthroplasty, with Staphylococcus epidermidis as the major pathogen. One important criteria to define PJI is the detection of phenotypically indistinguishable microorganisms with identical antibiotic susceptibility pattern in at least two different samples. However, owing to phenotypical variation within genetic clones and clonal variation within a phenotype, the criteria may be ambiguous. We investigated the extent of diversity among coagulase-negative staphylococci (CoNS) in PJI and characterised S. epidermidis isolates from PJI samples, specifically multiple S. epidermidis isolates identified in individual PJI patients. We performed a retrospective cohort study on 62 consecutive patients with PJI caused by CoNS from two hospitals in Northern Sweden. In 16/62 (26%) PJIs, multiple S. epidermidis isolates were available for whole-genome analyses. Hospital-adapted multidrug-resistant genetic clones of S. epidermidis were identified in samples from 40/62 (65%) of the patients using a combination of pulsed-field gel electrophoresis and multilocus sequence typing. Whole-genome sequencing showed the presence of multiple sequence types (STs) in 7/16 (44%) PJIs where multiple S. epidermidis isolates were available. Within-patient phenotypical variation in the antibiotic susceptibility and/or whole-genome antibiotic resistance gene content was frequent (11/16, 69%) among isolates with the same ST. The results highlight the ambiguity of S. epidermidis phenotypic characterisation as a diagnostic method in PJI and call for larger systematic studies for determining the frequency of CoNS diversity in PJIs, the implications of such diversity for microbiological diagnostics, and the therapeutic outcomes in patients., (© 2021. The Author(s).)

Prevention is an attractive solution for the staggering and increasingly unmanageable burden of osteoarthritis. Despite this, the field of osteoarthritis prevention is relatively immature. To date, most of what is known about preventing osteoarthritis and risk factors for osteoarthritis is relative to the disease (underlying biology and pathophysiology) of osteoarthritis, with few studies considering risk factors for osteoarthritis illness, the force driving the personal, financial and societal burden. In this narrative review we will discuss what is known about osteoarthritis prevention, propose actionable prevention strategies related to obesity and joint injury which have emerged as important modifiable risk factors, identify where evidence is lacking, and give insight into what might be possible in terms of prevention by focussing on a lifespan approach to the illness of osteoarthritis, as opposed to a structural disease of the elderly. By targeting a non-specialist audience including scientists, clinicians, students, industry employees and others that are interested in osteoarthritis but who do not necessarily focus on osteoarthritis, the goal is to generate discourse and motivate inquiry which propel the field of osteoarthritis prevention into the mainstream., (Copyright © 2021 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Objective: To describe early prosthesis implantations in a cohort of patients with juvenile idiopathic arthritis (JIA) followed in a tertiary referral hospital and to analyze possible factors influencing implant survival., Methods: This was a retrospective cohort study. Charts of all patients with JIA who underwent total joint replacement at Gaetano Pini Hospital, Milan, Italy from January 1992 to June 2019 were retrieved, and relevant data were analyzed., Results: Eighty-five patients met the inclusion criteria for this study, with a median follow-up period of 17.2 years. The median age at first prosthesis was 22.7 years. The total number of replaced joints was 198 over a period of 27 years. The hip was the most frequently replaced joint, accounting for almost two-thirds of the total number of implants; the other one-third refers mostly to knee implants. Polyarticular JIA and systemic JIA were the most represented JIA categories in the study cohort. A significant upward trend of the age at arthroplasty and of disease duration before arthroplasty over decades was found. The rates of implant survival at 5, 10, and 15 years were comparable (from 84% to 89%); 50% of implants lasted ≥20 years., Conclusion: We reported retrospective data on early joint replacement in a cohort of patients with JIA. We observed a progressive and significant upward trend of both age at arthroplasty and disease duration before the first arthroplasty over time. The JIA category, year of implant, and presence of complications significantly affected implant survivorship., (© 2020, American College of Rheumatology.)

Objective: To assess the proportion of participants reconsidering their willingness to undergo surgery after 3 and 12 months. Secondary aims were to analyze and compare the characteristics of individuals willing and unwilling to undergo joint surgery for osteoarthritis (OA) before a first-line intervention, and to study the association between pain intensity, walking difficulties, self-efficacy, and fear of movement with the willingness to undergo surgery., Methods: This was an observational study based on Swedish register data. We included 30,578 individuals with knee or hip OA who participated in a first-line intervention including education and exercise., Results: Individuals willing to undergo surgery at baseline showed a higher proportion of men (40% versus 27%) and more severe symptoms and disability. Respectively, 45% and 30% of the individuals with knee and hip OA who were willing to undergo surgery at baseline became unwilling after the intervention. At the end of the study period (12 months), 35% and 19% of those with knee and hip OA, respectively, who were willing to undergo surgery at baseline became unwilling. High pain intensity, walking difficulties, and fear of movement were associated with higher odds of being willing to undergo surgery at both follow-ups, while increased self-efficacy showed the opposite association., Conclusion: A first-line intervention for OA is associated with reduced willingness to undergo surgery, with a greater proportion among patients with knee OA than hip OA. Due to its temporal variability, willingness to undergo surgery should be used with care to deem surgery eligibility., (© 2020 The Authors. Arthritis Care & Research published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Purpose: To compare tibiofemoral contact mechanics after horizontal or ripstop (horizontal plus vertical) sutures in inside-out and transtibial repair for meniscal radial tears with 10 porcine knees in each group., Methods: Ten matched pairs of porcine knees were tested under a 1500-N axial compressive load at 0°, 30°, 60°, and 90° of knee flexion. Each knee underwent 4 testing conditions consecutively: (1) intact, (2) medial meniscal radial tear, (3) horizontal suture repair configuration, and (4) ripstop suture repair configuration. Tekscan sensors measured tibiofemoral contact pressure and contact area in the medial and lateral compartments., Results: All repair groups improved their contact mechanics when compared with the tear state among all flexion angles analyzed (all P < .05). Furthermore, ripstop sutures with both inside-out and transtibial repairs restored intact knee contact area and pressures (peak and mean) in the medial compartment at all flexion angles, whereas the horizontal sutures alone failed to do so for contact pressures at 60° and 90° and for contact surface areas at all flexion angles. However, the aforementioned parameters were not significantly different between inside-out sutures and transtibial sutures, regardless of horizontal or ripstop configuration (P > .05)., Conclusions: Radial tears of the meniscus in a porcine model significantly decreased medial contact area and increased mean and peak contact pressure. Both inside-out and transtibial ripstop repairs for radial tears aid in restoring intact tibiofemoral contact mechanics at all assessed knee flexion angles., Clinical Relevance: Our results suggest that both inside-out and transtibial ripstop repairs for radial tears can restore tibiofemoral contact mechanics to the intact state. Since the study were performed in an open fashion porcine model, the results should be carefully used in clinical practices, and the efficacy of the techniques through arthroscopic method should be further explored., (Copyright © 2020 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Biomechanical deviations at individual joints are often identified by gait analysis of patients with cerebral palsy (CP). Analysis of the control of joint and leg stiffness of the locomotor system during gait in children with spastic diplegic CP has been used to reveal their control strategy, but the differences between before and after surgery remain unknown. The current study aimed to bridge the gap by comparing the leg stiffness-both skeletal and muscular components-and associated joint stiffness during gait in 12 healthy controls and 12 children with spastic diplegic CP before and after tendon release surgery (TRS). Each subject walked at a self-selected pace on a 10-meter walkway while their kinematic and forceplate data were measured to calculate the stiffness-related variables during loading response, mid-stance, terminal stance, and pre-swing. The CP group altered the stiffness of the lower limb joints and decreased the demand on the muscular components while maintaining an unaltered leg stiffness during stance phase after the TRS. The TRS surgery improved the joint and leg stiffness control during gait, although residual deficits and associated deviations still remained. It is suggested that the stiffness-related variables be included in future clinical gait analysis for a more complete assessment of gait in children with CP., Competing Interests: The authors have declared that no competing interests exist.

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.

Purpose:  To determine MRI characteristics and the clinical presentation of intraarticular osteoid osteomas (OO) before and after treatment with CT-guided radiofrequency ablation (RFA) compared with extraarticular osteoid osteomas., Materials and Methods:  In a retrospective study, n = 21 patients with an intraarticular OO were matched with a control group of n = 21 patients with an extraarticular OO at a comparable anatomical position. All patients underwent CT-guided RFA and preinterventional MRI. In n = 31 cases, follow-up MR imaging was available. MR images were analyzed for morphologic features: effusion and synovitis, bone marrow edema (BME), soft tissue edema, periosteal reaction as well as T1 / T2 signal and contrast enhancement of the nidus. Recorded clinical parameters included the initial diagnosis, the course of pain symptoms after RFA and the incidence of complications., Results:  The nidus was detectable in all patients on MRI. BME had the highest sensitivity in both intra- and extraarticular OO (100 %). Effusion and synovitis were only observed in the intraarticular OO group (n = 21) with a perfect sensitivity and specificity (100 %) and a high negative predictive value (85 %). Soft tissue edema was significantly more present in patients with intraarticular OO (p = 0.0143). No significant differences were present regarding periosteal reaction, T1/T2 signal and contrast enhancement of the nidus (p > 0.05). BME, contrast enhancement, soft tissue edema, periosteal reaction, effusion and synovitis, if preexisting, always decreased after RFA. In 66.7 % of patients with intraarticular OO, a false initial diagnosis was made (extraarticular: 19 %). All patients were free of pain after intervention. Complications following the RFA procedure did not occur., Conclusion:  MRI demonstrates the nidus and thus the OO in all cases regardless of the location. The characteristic MRI morphology of an intraarticular OO includes synovitis and joint effusion, which are always present and differentiate with perfect sensitivity/specificity from an extraarticular OO. In both intra- and extraarticular OOs pathologic MRI changes at least decreased or completely normalized and the clinical results after RFA were excellent., Key Points:   · MRI is excellently suited for the diagnosis of intra- and extraarticular OOs.. · Joint effusion and synovitis distinguish both forms with perfect sensitivity and specificity.. · All MRI changes, which indicate activity, decreased after successful RFA.. · The clinical results after RFA are excellent in both forms.., Citation Format: · Germann T, Weber M, Lehner B et al. Intraarticular Osteoid Osteoma: MRI Characteristics and Clinical Presentation Before and After Radiofrequency Ablation Compared to Extraarticular Osteoid Osteoma. Fortschr Röntgenstr 2020; 192: 1190 - 1198., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Introduction: Measure and monitor adverse events (AEs) following hip arthroplasty is challenging. The aim of this study was to create a model for measuring AEs after hip arthroplasty using administrative data, such as length of stay and readmissions, with equal or better precision than an ICD-code based model., Materials and Methods: This study included 1 998 patients operated with an acute or elective hip arthroplasty in a national multi-centre study. We collected AEs within 90 days following surgery with retrospective record review. Additional data came from the Swedish Hip Arthroplasty Register, the Swedish National Patient Register and the Swedish National Board of Health and Welfare. We made a 2:1 split of the data into a training and a holdout set. We used the training set to train different machine learning models to predict if a patient had sustained an AE or not. After training and cross-validation we tested the best performing model on the holdout-set. We compared the results with an established ICD-code based measure for AEs., Results: The best performing model was a logistic regression model with four natural age splines. The variables included in the model were as follows: length of stay at the orthopaedic department, discharge to acute care, age, number of readmissions and ED visits. The sensitivity and specificity for the new model was 23 and 90% for AE within 30 days, compared with 5 and 94% for the ICD-code based model. For AEs within 90 days the sensitivity and specificity were 31% and 89% compared with 16% and 92% for the ICD-code based model., Conclusion: We conclude that a prediction model for AEs following hip arthroplasty surgery, relying on administrative data without ICD-codes is more accurate than a model based on ICD-codes., Competing Interests: The authors have declared that no competing interests exist.

We studied the effect of subbacteriostatic azithromycin concentrations on the formation of microbial biofilms by Pseudomonas aeruginosa strains that caused implant-associated infection of large joints. Azithromycin in subinhibitory for planktonic cells concentrations 0.01-0.02 μg/ml stimulated biofilm formation by both clinical and reference P. aeruginosa strains, while in concentrations of 1 μg/ml and higher completely inhibited the growth of both reference and clinical plankton P. aeruginosa strains, but stimulated biofilm formation. Increasing azithromycin concentration to 10 μg/ml led to inhibition of P. aeruginosa biofilm growth.

Deep prosthetic hip infection is a devastating complication of hip replacement surgery, and treatment often involves multiple revision surgeries with antibiotic chemotherapy to control the infection. The aim of this study was to explore patients' experiences of early and longer-term recovery after one-stage or two-stage revision with an excised hip, a temporary cement spacer or a custom-made articulating spacer. We interviewed 32 participants taking part in a surgical trial at two time points (2-4 months and 18 months) following one- or two-stage revision surgery. The analytic approach was inductive using the constant comparative method to generate themes from the data. Participants' early recovery after revision was characterised by a long hospital stay with burdensome antibiotics and limited physiotherapy provision. Participants undergoing two-stage revision with an excised hip or a cement spacer described severe mobility restrictions which affected all aspects of their lives, while those undergoing one-stage revision, or two-stage revision with an articulating spacer were more mobile and independent, with some limitations. Participants with a cement spacer also reported more pain than other treatment groups, while those with an articulating spacer appeared to perceive that their recovery was slow. At 18 months, participants in all groups described both improvements and losses in mobility and functional ability. Participants in all treatment groups expressed considerable emotional resilience during recovery from revision, which may be linked to opportunities to talk with the trial personnel. Participants identified the need for better information and psychological and physical support. Experience of recovery differs after one- and two-stage revision, and further in relation to the use of spacers. Mobility, function, independence and pain are important aspects of recovery which affect all aspects of day-to-day life. Increased information and more opportunities to talk and share experiences may provide psychological support during recovery., Competing Interests: Cecily K Palmer: I have read the journal's policy and as an author of this manuscript I have no competing interests. Andrew J Moore: I have read the journal's policy and as an author of this manuscript I have no competing interests. Rachael Gooberman-Hill: I have read the journal's policy and as an author of this manuscript I have no competing interests. Ashley W Blom: I have read the journal's policy and as an author of this manuscript I have no competing interests. Michael R Whitehouse: I have read the journal's policy and as an author of this manuscript I have no competing interests.

* Arthrofibrosis is a pathologic condition that is characterized by excessive periarticular scar-tissue formation. Arthrofibrosis may occur secondary to injury, surgical trauma, hemarthrosis, or infection, or it may occur idiopathically.* The pathogenesis of arthrofibrosis is incompletely understood but involves the dysregulation of normal reparative pathways, with transforming growth factor-beta (TGF-[beta]) as a principal mediator.* Current treatment options for arthrofibrosis primarily involve physiotherapy, operative manipulation, and surgical debridement, all with imperfect results.* Currently, there are no pharmacologic treatment options for arthrofibrosis. This has prompted increased investigational interest in the development of antifibrotic intra-articular therapies.

Objectives: The purpose of this study was to explore the role of mNGS in the diagnosis of PJI by detecting the presence of bacteria in periprosthetic tissues., Methods: Patients who were suspected of PJI and underwent surgery in our center were enrolled. Microbial culture and mNGS were performed on periprosthetic tissues collected intraoperatively. Patient age, body mass index (BMI), laboratory tests, microbial culture and mNGS results were recorded. The diagnostic performance of microbial culture and mNGS in the diagnosis of PJI was compared., Results: A total of 44 patients were included. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of periprosthetic tissue microbial culture in the diagnosis of PJI were 72.72%, 77.27%, 76.19%, 73.91% and 75%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of periprosthetic tissue mNGS in the diagnosis of PJI were 95.45%, 90.91%, 91.3%, 95.24% and 93.18%, respectively. The sensitivity and specificity of mNGS in the diagnosis of PJI were superior to those of microbial culture., Conclusion: Periprosthetic tissue can be used as an alternative to synovial fluid and sonication fluid, as mNGS can improve the diagnosis of PJI. mNGS of the periprosthetic tissues showed higher sensitivity than microbial culture., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: The economic effects of the COVID-19 crisis are not like anything the U.S. health care system has ever experienced., Methods: As we begin to emerge from the peak of the COVID-19 pandemic, we need to plan the sustainable resumption of elective procedures. We must first ensure the safety of our patients and surgical staff. It must be a priority to monitor the availability of supplies for the continued care of patients suffering from COVID-19. As we resume elective orthopedic surgery and total joint arthroplasty, we must begin to reduce expenses by renegotiating vendor contracts, use ambulatory surgery centers and hospital outpatient departments in a safe and effective manner, adhere to strict evidence-based and COVID-19-adjusted practices, and incorporate telemedicine and other technology platforms when feasible for health care systems and orthopedic groups to survive economically., Results: The return to normalcy will be slow and may be different than what we are accustomed to, but we must work together to plan a transition to a more sustainable health care reality which accommodates a COVID-19 world., Conclusion: Our goal should be using these lessons to achieve a healthy and successful 2021 fiscal year., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objectives: Human amniotic epithelial cells have multipotent differentiation capacity and are considered as potential therapeutic cells for clinical use. This study represents the first published report on the evaluation of the safety and clinical feasibility of human amniotic epithelial cells for transplant into knee joints, serving as an initial step for subsequent therapeutic evaluations within arthritis clinics., Materials and Methods: Our experimental design was based on subjecting groups of rabbits as a recipient model for human amniotic epithelial cell transplant into knee joints. Twenty rabbits received 200 μL sterile 0.9% sodium chloride solution containing 1 × 10⁹ human amniotic epithelial cells/knee joint by intra-articular injection. Control groups received cell-free saline into knees, and some animals were not treated. After 10 days of xenotransplant, radiology scans and histologic sections of transplanted and nontrans planted knees were examined and compared. Immunohistochemistry staining was also applied to detect tumor necrosis factor-alpha and interleukin 17 (as inflammatory and immuno-rejection markers) in knee sections., Results: Similar to results shown in noninjected and saline-injected knees, all treated knees appeared normal, with no signs of acute immunorejection, no microbial colonization, no pain, no allergic reactions, no inflammation, and normal motion. Use of human amniotic epithelial cells appeared safe without risk of immunorejection or tumor formation in the transplanted knee joint., Conclusions: Human amniotic epithelial cells can be safely transplanted into knee joints, encouraging a need for complementary research for further therapeutic evaluations of human amniotic epithelial cells for curing arthritis.

Current biomaterials and tissue engineering techniques have shown a promising efficacy on full-thickness articular cartilage defect repair in clinical practice. However, due to the difficulty of implanting biomaterials or tissue engineering constructs into a partial-thickness cartilage defect, it remains a challenge to provide a satisfactory cure in joint surface regeneration in the early and middle stages of osteoarthritis. In this study, we focused on a ready-to-use tissue-adhesive joint surface paint (JS-Paint) capable of promoting and enhancing articular surface cartilage regeneration. The JS-Paint is mainly composed of N -(2-aminoethyl)-4-(4-(hydroxymethyl)-2-methoxy-5-nitrosophenoxy) butanamide (NB)-coated silk fibroin microparticles and possess optimal cell adhesion, migration, and proliferation properties. NB-modified silk fibroin microparticles can directly adhere to the cartilage and form a smooth layer on the surface via the photogenerated aldehyde group of NB reacting with the -NH 2 groups of the cartilage tissue. JS-Paint treatment showed a significant promotion of cartilage regeneration and restored the smooth joint surface at 6 weeks postsurgery in a rabbit model of a partial-thickness cartilage defect. These findings revealed that silk fibroin can be utilized to bring about a tissue-adhesive paint. Thus, the JS-Paint strategy has some great potential to enhance joint surface regeneration and revolutionize future therapeutics of early and middle stages of osteoarthritis joint ailments.

Abnormal accumulation of neutrophils in a subarticular bone usually raises the concern for osteomyelitis or septic arthritis, a disabling and potentially life-threatening medical condition. At the pathology department of a specialized orthopedic institute, we observed a distinct pattern of subarticular inflammation mimicking infection characterized by collections of neutrophils, macrophages, and fibrin in pseudocystic spaces of variable size and extent in the superficial subarticular bone not accompanied by granulation tissue or necrosis. We coined the term "inflammatory pseudoabscess" to describe these accumulations. From 1997-2015, we reported inflammatory pseudoabscesses in 157 primary arthroplasty/osteotomy specimens from 143 patients without penetrating trauma or hardware in the affected joint. The predominant gross and histologic features were those of destructive/inflammatory joint disease, including lymphoplasmacytic synovitis (95.3%), subchondral osseous chronic inflammation (80.3%), exudative synovitis (58.0%), synovial pannus (52.0%), and marginal erosions of articular cartilage and/or subarticular bone (43.3%). Clinical information was available in 137 (95.8%) patients, 107 (overall: 74.8%) of whom had preoperatively or postoperatively diagnosed inflammatory arthropathy, most commonly rheumatoid arthritis. The remaining 30 (overall: 21.0%) patients had no documented inflammatory disorders, but some had bilateral or multijoint arthropathy, hands/feet involvement, lymphoplasmacytic synovitis, ulcerative colitis, or family history of inflammatory arthropathy. There was no documented infection-associated implant failure. We believe that inflammatory pseudoabscess represents an intraosseous manifestation of noninfectious inflammatory disorders of joints. This feature should be recognized by pathologists and used to suggest further clinical evaluation for undiagnosed inflammatory joint diseases.

Objective: This study compares the mechanical stability and surgical usability of 2 locking plate systems (Kyon ALPS-20 and Synthes PIP-LCP system) for arthrodesis of the equine proximal interphalangeal joint (PIJ)., Material and Methods: The experimental ex vivo study included 6 pairs of cadaver distal limbs (n = 12). All specimens were derived from Warmblood horses of various ages that were euthanized for non-orthopedic reasons. Of the 12 limbs collected, 3 left and 3 right distal limb specimens were randomly assigned to each system for implantation. Two abaxial 4.5-mm cortical screws were inserted transarticularly in all cases. Both systems were implanted according to the manufacturer's instructions with the plates placed centrally between the 2 transarticular screws. The ALPS-20 systems were implanted using Kyon B-6.4-mm monocortical locking screws in all positions. The LCP systems were implanted axially using 2 Synthes 5-mm locking screws in the proximal and distal positions, with a standard 4.5-mm cortical screw inserted in the middle position. All constructs underwent CT-scans after implantation and biomechanical testing to detect implant deformation. Uniaxial mechanical loading was applied via a servo-hydraulic test system at a test speed of 50 mm/s, up to a maximum displacement of 80 mm. The resulting load-displacement curves were used to calculate yield point, stiffness, and maximum force for each construct. The measured values were evaluated for statistical significance (p < 0.05) between the 2 plate systems via one-factor ANOVA (Tukey test). The statistical power was verified for yield force, stiffness, and maximum load., Results: No statistically significant differences between the 2 preparation groups were calculated across all of the measured parameters (p > 0.05). The ALPS system implants showed no signs of deformation, either in the plates or the screws. In contrast, the LCP demonstrated visible deformation, which had already occurred at the time of implantation from the tightening of the middle screw, as well as during the subsequent testing of the implants. After biomechanical testing, deformations ranging between 3.1° and 7.0° were measured in 4 LCPs. A total implant failure was observed for 2 LCPs., Conclusion and Clinical Relevance: Both systems demonstrated comparable mechanical properties in the present study's ex vivo test model for equine PIJ arthrodesis. As such, the Kyon ALPS-20 may be a good alternative to the Synthes LCP for equine PIJ arthrodesis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© Georg Thieme Verlag KG Stuttgart · New York.)

Evaluation of periarticular traumatic wounds for joint penetration is a common clinical concern for orthopaedic surgeons. Wounds that violate the joint capsule can result in deep infection and sepsis. Understanding the anatomic landmarks and capsular extensions of the major joints is key to proper evaluation. Initial evaluation of periarticular wounds includes thorough examination of the wound and plain radiographs. Historically, the saline load test has been the diagnostic test of choice for assessing traumatic arthrotomy; however, CT has recently been shown to have excellent sensitivity and specificity for detecting open knee joint injuries. Current treatment of traumatic arthrotomy includes intravenous antibiotics and surgical irrigation and débridement. Future areas of research must focus on further validation of CT evaluation and its use in other major joints, standardizing antibiotic treatment, and further delineating the role of nonsurgical management in minor injuries.

Articular fractures are common injuries in veterinary medicine. The principles of articular fracture repair are anatomic reduction and rigid fixation in order to optimize joint function. Fluoroscopy and arthroscopy are tools commonly used to allow for anatomic reduction with a minimally invasive approach. Minimally invasive techniques can decrease morbidity and promote an early return to function. Different types of articular fractures and options for minimally invasive repair are reviewed in this article., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: Osteoarthritis is a common disease with a prevalence of approximately 8.9% among the average population. One treatment option is low-dose radiotherapy. Some authors mention that they apply a second or third course of radiation for recurrent pain or partial or no response to the initial course. As the results of re-irradiation have not been analysed systematically, the aim of this study was to document the results of repeated radiation treatment and to identify those patients who will benefit., Methods and Materials: The analysis was performed on patients of three German radiotherapy institutions and included 217 re-irradiated joints. Pain was documented with the numeric rating scale (NRS). Evaluation of the NRS was done before and directly after each radiation therapy as well as at the follow-up of 24 months. The median age of the patients was 67 years, with 40% male and 60% female patients. Re-irradiation was indicated because the initial radiotherapy resulted in no response in 21.2%, in partial response in 41.5%, and in recurrent pain in 37.3%., Results: We found a significant response to re-irradiation. For the whole sample, the median pain was 6 before re-irradiation, 4 after 6 weeks, and 3 after 12 weeks, 6 months, 12 months, and 24 months. The percentage of patients being free of pain or with very little pain was approximately 25% 12 months after re-irradiation. All subgroups, notably those with no response to the first course versus partial response to the first course versus recurrent pain, had significant reduction of pain., Conclusion: Re-irradiation of osteoarthritis is an effective and safe treatment. All subgroups showed a good response to re-irradiation for at least 24 months.

Objective: To investigate time-trends and cumulative incidence of joint surgery among patients with psoriatic arthritis (PsA) compared with the general population., Methods: In this nationwide register-based cohort study, The Danish National Patient Registry was used to identify incident PsA patients. The 5-year incidence rates (IR) and incidence rate ratios (IRR) of joint surgery were calculated in four calendar-period defined cohorts. Each patient was matched with ten non-PsA individuals from the general population cohort (GPC). The cumulative incidences of any joint and joint-sacrificing surgery, respectively, were estimated using the Aalen-Johansen method., Results: From 1996 to 2017, 11 960 PsA patients (mean age 50 years; 57% female) were registered. The IRR of any joint surgery was twice as high for PsA patients compared with GPCs across all calendar periods. Among patients with PsA, 2, 10 and 29% required joint surgery at 5, 10 and 15 years after diagnosis. The risk of surgery in PsA patients diagnosed at 18-40 years was higher (22%) than in GPC 60+ year old (20%) after 15 years of follow-up., Conclusions: The use of joint surgery among PsA patients remained around twofold higher from 1996 to 2012 compared with GPC. After 15 years of follow-up, nearly 30% of the PsA patients had received any surgery, and even a person diagnosed with PsA at the age of 18-40 years had a higher risk of surgery than GPCs of 60+ year old. Thus, the high surgical rates represent an unmet need in the current treatment of PsA., Competing Interests: Competing interests: JG-M has received speaking fees from AbbVie, Eli Lilly and BK Ultrasound outside the present work. RLC has no competing interests. LEK has received fees for speaking and/or consultancy from Pfizer, AbbVie, Amgen, UCB, Celgene, BMS, Biogen, Sanofi, MSD, Novartis, Eli Lilly, Janssen Pharmaceuticals. LD has received speaking fees from UCB, MSD, Eli-Lilly and Janssen Pharmaceuticals outside the present work., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To describe the presence of fragments in the dorsal proximal interphalangeal (PIP) joint and to report flat racing performance after surgical treatment., Study Design: Retrospective study., Sample Population: Thirty-nine affected thoroughbred flat racehorses and 169 age- and sex-matched maternal siblings., Methods: Medical records from 2000 to 2015 were reviewed for thoroughbred horses that underwent arthroscopic removal of osteochondral fragments in the dorsal aspect of the PIP joint. The horses' 2-year-old year, 3-year-old year, and career athletic performances were compared with their matched siblings., Results: Thirty-nine thoroughbred horses were included, varying in age from 4 months to 4 years, with osteochondral fragments in 42 PIP joints. Hind limbs (92%) were more commonly affected than forelimbs (8%). Fragments were located within the origin of the collateral ligament of the distal sesamoid (navicular) bone. After surgery, the likelihood of starting a race did not differ between treated horses (27/39 [69%]) and maternal siblings (129/169 [76%], P = .15). Race earnings did not differ between treated horses and their siblings during their 2-year-old year (P = .66), 3-year-old year (P = .43), or career (P = .60)., Conclusion: Removing osteochondral fragments from the origin of the collateral ligament of the distal sesamoid bone did not impair the ability to race or earning potential for affected thoroughbred racehorses compared with their maternal siblings., Clinical Significance: Fragments from the dorsal aspect of the PIP joint in racehorses can be removed arthroscopically resulting in a good clinical outcome and future flat racing performance comparable to matched controls., (© 2019 The American College of Veterinary Surgeons.)

Introduction. Prosthetic joint infections (PJIs) are challenging to treat therapeutically because the infectious agents often are resistant to antibiotics and capable of abundant growth in surface-attached biofilms. Though infection rates are low, ca. 1-2 %, the overall increase in the sheer number of joint replacement surgeries results in an increase in patients at risk. Aims. This study investigates the consensus of microbial species comprising PJI ecology, which is currently lacking. Methodology. In this study, PJI populations from seven patients were analysed using combined culturing and whole-genome shotgun sequencing (WGSS) to establish population profiles and compare WGSS and culture methods for detection and identification of the PJI microbiome. Results. WGSS detected strains when culture did not, notably dormant, culture-resistant and rare microbes. The CosmosID algorithm was used to predict micro-organisms present in the PJI and discriminate contaminants. However, culturing indicated the presence of microbes falling below the WGSS algorithm threshold. In these instances, microbes cultured are believed to be minor species. The two strategies were combined to build a population profile. Conclusions. Variability between and among PJIs showed that most infections were distinct and unique. Comparative analysis of populations revealed PJIs to form clusters that were related to, but separate from, vaginal, skin and gut microbiomes. Fungi and protists were detected by WGSS, but the role of fungi is just beginning to be understood and for protists it is unknown. These micro-organisms and their novel and strain-specific microbial interactions remain to be determined in current clinical tests.

Individuals with Arthrogryposis Multiplex Congenita (AMC) are born with multiple joint contractures in multiple body areas, typically manifested as clubfeet, extended or flexed knees and/or elbows, and internal shoulder rotation, and clasped hands. They require multiple surgeries as children, but there is little data that reports their aging and future quality of life (QOL). This study describes the relationship between AMC-related surgically-managed joints in childhood and adulthood, and QOL as adults. Participants (n = 83) from 14 countries completed an online questionnaire followed by a telephone/Skype interview as adults. Data points collected regarding total number of surgeries, affected joints, country of origin, sex, age, and SF-36's Physical Capacity Score (PCS) for QOL were analyzed using a beta regression model to explore which factors may potentially influence adult QOL. The average number of surgeries per participant was 9.8, with at least 50% performed during childhood. 78, 45, and 31% of participants had foot, knee, and hip surgeries, respectively. The model demonstrated that knee and/or shoulder surgeries were more likely to have a negative correlation with PCS; elbow surgery, however, showed a positive correlation, as elbow function may impact independent function. However, future expansion of this data set to a longitudinal registry would provide better ongoing surgery-specific data., (© 2019 Wiley Periodicals, Inc.)

Objective:  The aim of this study was to determine if articulated joint distraction in the canine elbow can effectively maintain a distraction gap between the articular surfaces of the canine elbow under a weight-bearing load., Study Design:  An articulated external skeletal fixator with turnbuckles was applied to seven canine cadaveric elbow specimens. Specimens were potted and mechanically tested at 135° of flexion, while joint contact pressure was recorded at three locations within the elbow. Joint distraction was sequentially increased, and loads of 5 N, 90 N and 180 N were incrementally applied. This process was repeated until no pressure was recorded at each of the three locations within the elbow under 180 N of applied load., Results:  To achieve 0 N of joint contact force with 180 N of axial load, the average amount of distraction needed was 2.3 ± 0.71 mm (range, 1.8-3.6 mm) at the distal turnbuckles and 1.67 ± 1.10 mm (range, 1.8-2.7 mm) at the proximal turnbuckles., Conclusion:  Results suggest that joint distraction can effectively decrease articular pressure within the canine elbow joint. A maximum of 3.6 mm of distraction between the fixator turnbuckles was necessary to eliminate joint contact for the construct tested. Clinical investigation is necessary to establish if articulated elbow joint distraction is a safe and effective for the treatment of canine elbow osteoarthritis., Competing Interests: None declared., (Georg Thieme Verlag KG Stuttgart · New York.)

Introduction: Identifying the source of pain is paramount for determining appropriate treatment and ensuring successful outcome in terms of management and relief of pain. The difficulty is that each surgeon has his or her own way of seeing the problem, and there is no consensus for the evaluation of these patients. The study hypothesis was that it is possible to find the cause of the pain in most cases., Patients and Methods: All patients consulting for unexplained painful hip arthroplasty were included and followed a decision tree to assess the cause of the pain. The primary endpoint was the final diagnosis. Secondary endpoints were subgroup comparison between main causes and assessment of risk factors., Results: Two hundred one hips of 194 patients were included as unexplained painful hip arthroplasty 6 months postoperatively. Final diagnoses comprised periarticular pain in 53 cases (26.4%): 40 cases of trochanteric bursitis, 5 of iliopsoas tendinitis, 5 of abductor deficiency, 1 of ischial tuberosity tendinitis, and 2 of heterotopic ossification; projected pain in 49 (24.4%): 45 cases of back pain with or without neuropathy, 3 of knee osteoarthritis, and 1 of metabolic neuropathy; wear in 40 (19.9%), in the polyethylene liner; loosening in 20 (10.0%): loosening of the femoral component in 8 and that of the cup in 12; material problems in 17 (8.5%): trunnionosis in 13 and metallosis in metal-on-metal implants in 4; no diagnosis in 7 hips (3.5%); infection in 6 (3.0%), all chronic; instability without real dislocation in 3 (1.5%); misplacement in 3 (1.5%), all for leg-length discrepancy; fracture in 2 (1.0%): 1 of greater trochanter and 1 of ilio-ischiopubic ramus; complex regional pain syndrome in 1 (0.5%)., Discussion: To our knowledge, this is the first study on the causes of painful hip arthroplasty in clinical practice, whether leading to revision or not. A systematic approach, including physical examination, radiographic assessment and laboratory studies, is needed to find the cause of the pain. It is important to understand the pain so that it can be treated appropriately. Revision surgery can sometimes help-but the worst thing is to make the patient worse., Level of Evidence: level 4, retrospective study., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: It is currently unknown to what extent routine histological examination of joint arthroplasty specimens occurs across hospitals nationwide. Although this practice is neither supported nor refuted by the available evidence, given the increasing demand for joint arthroplasties, it is crucial to study overall utilization as well as its main drivers., Questions/purposes: Using national data on joint replacements, we aimed to evaluate: (1) What is the current use of routine histological examination of joint arthroplasty specimens? (2) Does the use vary by geographic location and hospital characteristics? (3) Has use changed over time?, Methods: From the Premier Healthcare database (2006-2016) we included claims data from 87,667 shoulder (595 hospitals, median age 70 years, 16% nonwhite), 564,577 hip (629 hospitals, median age 65 years, 21% nonwhite), and 1,131,323 (630 hospitals, median age 66 years, 24% nonwhite) knee arthroplasties (all elective). Our study group has extensive experience with this data set, which contains information on 20% to 25% of all US hospitalizations. Included hospitals are mainly concentrated in the South (approximately 40%) with equal distributions among the Northeast, West, and Midwest (approximately 20% each). Moreover, the Premier data set has detailed billing information, which allows for evaluations of real-world clinical practice. There was no missing information on the main variables of interest for this specific study. We assessed frequency of histology examination (defined by Current Procedural Terminology codes) overall as well as by hospital characteristics (urban/rural, bed size, teaching status, arthroplasty volume), geographic region (Northeast, South, Midwest, West), and year. Given the large sample size, instead of p values, standardized differences were applied in assessing group differences where a standardized difference of > 0.1 (or 10%) was assumed to represent a meaningful difference between groups. For significance of trends, p values were applied. Percentages provided represent proportions of individual procedures., Results: In most hospitals, histology testing was either rare (1%-10%, used in 187 of 595, 189 of 629, and 254 of 630 hospitals) or ubiquitous (91%-100%, used in 121 of 595, 220 of 629, and 195 of 630 hospitals) for shoulder, hip, and knee arthroplasties, respectively. Overall, histology testing occurred more often in smaller hospitals (37%-53% compared with 26%-45% in larger hospitals) and those located in the Northeast (59%-68% compared with 22%-44% in other regions) and urban areas (32%-49% compared with 20%-31% in rural areas), all with standardized differences > 10%. Histologic examination is slowly decreasing over time: from 2006 to 2016, it decreased from 34% to 30% for shoulder arthroplasty, from 50% to 45% for THAs, and from 43% to 38% for TKAs (all p < 0.001)., Conclusions: Although overall use is decreasing, a substantial number of hospitals still routinely perform histology testing of arthroplasty specimens. Moreover, variation between regions and hospital types suggests that this practice is driven by a variety of factors. This is the first study addressing national utilization, which will be helpful for individual hospitals to assess how they compare with national utilization patterns. Moreover, the findings have clear implications for followup studies, which may be necessary given the exponentially growing demand for arthroplasties., Level of Evidence: Level III, therapeutic study.

Introduction: Many patients with osteoarthritis (OA) develop restrictions in passive range of motion (ROM) of their affected joints (called contractures), leading to increased pain and reduced function. Effective treatment to reverse OA-associated contractures is lacking. Our aim is to evaluate the effectiveness of stretching and bracing on native (non-operated) joint contractures in people with radiographically diagnosed OA., Methods and Analysis: We will search the following databases without time restriction: Cochrane Library (CENTRAL, Database of Abstracts of Reviews of Effects, Health Technology Assessment Database), MEDLINE, Embase, CINAHL, SCI-EXPANDED (ISI Web of Knowledge) and PEDro. Other sources will include WHO International Clinical Trials Registry Platform, reference lists of included studies, relevant systematic reviews and textbooks. We will include randomised controlled trials (RCTs), controlled clinical trials, controlled before-and-after studies, cohort studies and case-control studies that include participants ≥18 years of age with radiographic evidence of OA. Participants with inflammatory arthropathies or those that have undergone joint arthroplasty will be excluded. Interventions will include therapist-administered or patient-administered stretching, use of an orthosis (static or dynamic), use of serial casting and/or adjunctive modalities. Outcomes will include joint ROM (active and passive), pain (rest and/or activity related), stiffness, activity limitations, participation restrictions, quality of life and adverse events. Studies will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Study inclusion, data extraction and quality assessment will be performed independently by two reviewers. Risk of bias will be assessed using appropriate tools for each study design. Data synthesis will be performed using Cochrane Review Manager software. If sufficient data are available, meta-analysis will be conducted. We will summarise the quality of evidence using Grading of Recommendations Assessment, and the effect size of interventions for RCT and non-RCT studies., Ethics and Dissemination: Ethics approval not required because individual patient data are not included. Findings will be disseminated in a peer-reviewed journal., Prospero Registration Number: CRD42019127244., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Antibiotic cement spacers are used during 2-stage revision total hip arthroplasty for prosthetic joint infection. Complications including dislocation and periprosthetic fracture have been reported but a large cohort comparing spacer design features is lacking. We aimed to determine if spacer design is associated with perioperative complications., Methods: We performed a retrospective review of antibiotic cement spacers implanted between 2004 and 2014. Radiographic assessment included leg length, offset, and bone loss (Paprosky classification). Clinical outcomes included dislocation, periprosthetic fracture, spacer fracture, infection cure, and overall reoperation rate. Univariate analysis, Student's t-test, chi-squared test, or Kruskal-Wallis test was employed (P < .05)., Results: One hundred eighty-five patients were treated: 42% were female and mean age was 64 years (range 24-93, standard deviation 13.6). Spacer types were (1) molded (53%), (2) antibiotic-coated prosthesis (30%), (3) handmade (12%); and (4) prefabricated (4%). Cemented acetabular liners were used in 3% (6/185). There was no loss to follow-up during the interstage period. Spacer complications occurred in 26% (48/185). Dislocation occurred in 9% (17/185) and was associated with reduced femoral offset of >5 mm (P = .033) and increased bone loss (P = .01). Spacer fracture occurred in 8% (14/185); 12% (12/97) molded versus 8% (2/23) handmade (P = .02). Periprosthetic femur fracture was associated with increased offset >5 mm (P = .01) and extended trochanteric osteotomy (P = .001)., Conclusion: During 2-stage total hip arthroplasty, antibiotic-loaded cement spacers had an overall complication rate of 26%. Spacer design, acetabular and femoral bone loss, and offset restoration were significantly associated with perioperative complications. We recommend the optimization of antibiotic-loaded cement spacer placement to minimize potential complications by focusing on restoration of leg-length and offset, ensuring adequate femoral fixation and paying attention to selection of an appropriate head/neck ratio., (Copyright © 2019 Elsevier Inc. All rights reserved.)