Treatment of anterior knee pain due to chondromalacia patellae with platelet-rich plasma and hyaluronic acid in young and middle-aged adults, a cohort study

INTRODUCTION

Anterior knee pain commonly affects young women resulting in the declination of the quality of life. One of the possible pathologies causing this symptom is chondromalacia patellae (CMP). Although CMP is used to describe the softening of patellar articular cartilage, it remains a general descriptive term as it cannot be associated with a specific pathophysiologic mechanism. The objective of this study is to investigate the effect of injectable PRP on patients with anterior knee pain in absence of altered patellofemoral joint anatomy.

METHODS

For this purpose, 43 patients of the affected population were recruited to participate in this non-randomized controlled trial, 28 patients in the injection group and 15 in the only-physiotherapy group. While patients in the experimental group received three PRP injections and one injection of hyaluronic acid (HA), comparators received the standard physical therapy regimen. The treatment choice was based on patients own decree. Patients between the ages of 18 to 50 years with anterior knee pain and positive Clarke´s sign were eligible for inclusion. Patients with evident anatomical abnormalities, chronic conditions affecting the knee and severe symptoms such as blocking, were excluded from the study. Patient related measures (PROMS) in the form of the VAS and the Kujala scores were the main outcome of interest. All outcomes were measured at baseline, and after 3 and 6 months after the treatment.

RESULTS

Although an improvement was seen in both groups, a statistically significant difference favoring the injection of PRP over the physiotherapy-only group was observed (p < 0.001). The superiority of the therapeutic modality under investigation was observed at 3 and 6 months after the initial diagnosis was made. Furthermore, the results of this study revealed a significant improvement at 3 and 6 months when compared to baseline measures. The analysis of the patients age showed a negative correlation when baseline values were compared to measures at 3 and 6 months, meaning younger patients had more benefit from the treatment.

DISCUSSION

The main results of this study affirm the positive effects of PRP and HA for the treatment of anterior knee pain described by previous research and the subsequent improvement of the quality of life. Relatively little information was found in the literature search regarding the therapeutic effects of PRP on anterior knee pain and chondropathies. While a previous radiologic study found no evidence regarding the effect of PRP, this study found a benefit when comparing PROMs between patient groups.

Patient-related Predictors for the Functional Outcome of SuperPATH Hemiarthroplasty versus Conventional Approach Hemiarthroplasty: A Systematic Review and Meta-regression Analysis of Randomized Controlled Trials

Specialist literature lacks evidence that explores associations between patient characteristics and the beneficial treatment effect of SuperPATH hemiarthroplasty (HA) compared with conventional approach (CA) HA. To investigate and identify patient-related predictors of the effect size of the short-term functional outcome of SuperPATH HA and CA HA by performing a systematic review and meta-regression analysis of randomized controlled trials (RCTs). A systematic search of literature was performed in PubMed, CNKI, CENTRAL of The Cochrane Library, Clinical trials, and Google Scholar until August 25, 2023. For the continuous outcome parameter Harris hip score (HHS) ≤1 week and 3 months postoperatively, mean differences (MDs) with 95% confidence intervals (CIs) were calculated. A meta-regression analysis was based on random-effects meta-analysis using the Hartung-Knapp-Sidik-Jonkman method for continuous covariates. A total of five RCTs with 404 patients were found. The following predictors of HHS ≤1 week postoperatively were identified: patient age (predictor estimate = 1.29; p < 0.01), patient age groups (predictor estimate = 14.07; p < 0.01), time to mobilization (predictor estimate = 5.51; p < 0.01). The following predictors of HHS 3 months postoperatively were identified: incision length (predictor estimate = -2.12; p < 0.01); intraoperative blood loss (predictor estimate = 0.02; p < 0.01). Patient age, time to mobilization, incision length, and intraoperative blood loss were identified as predictors of the effect size of early postoperative functional outcome as measured by HHS. Elderly patients, particularly those over 70 years of age, appear to benefit from SuperPATH HA. Based on these findings, and taking into account our limitations, we recommend that the use of minimally invasive SuperPATH HA in elderly patients should be more widely considered and not limited to elective THA patients.

Physical Therapies for Delayed Onset Muscle Soreness: A Protocol for an Umbrella and Mapping Systematic Review with Meta-Meta-Analysis

BACKGROUND

Delayed onset muscle soreness (DOMS), also known as exercise-induced muscle damage (EIMD), is typically caused by strenuous and/or unaccustomed physical exercise. DOMS/EIMD manifests itself in reduced muscle strength and performance levels, increased muscle soreness, swelling, and elevated levels of inflammatory biomarkers. Numerous randomised controlled trials (RCTs) and systematic reviews (SRs) of a wide variety of physiotherapy interventions for reducing the signs and symptoms of DOMS/EIMD have been published. However, these SRs often arrive at contradictory conclusions, impeding decision-making processes.

OBJECTIVE

We will systematically review the current evidence on clinical outcomes (efficacy, safety) of physiotherapy interventions for the treatment of DOMS/EIMD in healthy adults. We will also assess the quality of the evidence and identify, map, and summarise data from the available SRs.

METHOD

Umbrella review with evidence map and meta-meta-analyses. MEDLINE, Embase, Cochrane Database of Systematic Reviews, Epistemonikos and PEDro will be searched from January 1998 until February 2024. SRs of RCTs of any treatment used by physiotherapists (e.g., low-level laser therapy, electrical stimulation, heat/cold therapy, ultrasound, magnets, massage, manual therapies) to treat DOMS/EIMD in healthy adults will be eligible. Narrative/non-systematic reviews, studies of adolescents/children and medically compromised individuals, of complementary therapies, dietary, nutritional, or pharmacological interventions, as well as self-administered interventions, or those published before 1998, will be excluded. AMSTAR 2 will be used to evaluate the methodological quality of the included SRs. Corrected covered area, will be computed for assessing overlaps among included SRs, and an evidence map will be prepared to describe the credibility of evidence for interventions analysed in the relevant SRs.

DISCUSSION

DOMS/EIMD is a complex condition, and there is no consensus regarding the standard of clinical/physiotherapeutic care. By critically evaluating the existing evidence, we aim to inform clinicians about the most promising therapies for DOMS/EIMD. This umbrella review has the potential to identify gaps in the existing evidence base that would inform future research. The protocol has been registered at PROSPERO (CRD42024485501].

High three-dimensional accuracy of component placement and lower limb alignment using a robotic arm-assisted system and gap-balancing instrument in total knee arthroplasty

PURPOSE

It was hypothesized that robotic arm-assisted total knee arthroplasty (RA-TKA) using additionally a gap-balancing instrumentation will show high accuracy in executing the planning in femoral and tibial component placement throughout the range of knee motion (ROM) during TKA surgery.

METHODS

Prospectively collected data were analysed for patients undergoing RA-TKA. A cruciate retaining cemented design was implanted using the MAKO® robotic system. Lower limb alignment at 0°, 30°, 45°, 60° and 90° of flexion was recorded at the beginning of surgery and finally after implantation of the components. A ligament tensioner was inserted after tibial precut to measure the extension and flexion gap, and final component placement was planned based on 3D CT images. Femoral and tibial component placement was measured in all three planes.

RESULTS

A total of 104 patients were included (mean age 69.4 ± 9 years; 44 male, 60 female). The difference in component placement after planning and final implantation showed less valgus of 0.7° ± 1.4° (p < 0.001), less external rotation of 0.6° ± 1.9° (p = 0.001) and less flexion of 0.9° ± 1.8° (p < 0.001) for the femoral component. The tibial component was placed in more varus of 0.2° ± 0.9° (p = 0.056) and more posterior slope of 0.5° ± 0.9° (p < 0.001). The lower limb alignment in extension was 4.4° ± 5.2° of varus of the native knee and changed to 1.2° ± 1.9° of varus after TKA (p < 0.01).

CONCLUSION

Robotic-assisted TKA helps to achieve the target of alignment and component placement very close to the planning. It allows optimal component placement of off-the-shelf implants respecting patient's specific anatomy.

LEVEL OF EVIDENCE

Level II.

Human-Written vs AI-Generated Texts in Orthopedic Academic Literature: Comparative Qualitative Analysis

BACKGROUND

As large language models (LLMs) are becoming increasingly integrated into different aspects of health care, questions about the implications for medical academic literature have begun to emerge. Key aspects such as authenticity in academic writing are at stake with artificial intelligence (AI) generating highly linguistically accurate and grammatically sound texts.

OBJECTIVE

The objective of this study is to compare human-written with AI-generated scientific literature in orthopedics and sports medicine.

METHODS

Five original abstracts were selected from the PubMed database. These abstracts were subsequently rewritten with the assistance of 2 LLMs with different degrees of proficiency. Subsequently, researchers with varying degrees of expertise and with different areas of specialization were asked to rank the abstracts according to linguistic and methodological parameters. Finally, researchers had to classify the articles as AI generated or human written.

RESULTS

Neither the researchers nor the AI-detection software could successfully identify the AI-generated texts. Furthermore, the criteria previously suggested in the literature did not correlate with whether the researchers deemed a text to be AI generated or whether they judged the article correctly based on these parameters.

CONCLUSIONS

The primary finding of this study was that researchers were unable to distinguish between LLM-generated and human-written texts. However, due to the small sample size, it is not possible to generalize the results of this study. As is the case with any tool used in academic research, the potential to cause harm can be mitigated by relying on the transparency and integrity of the researchers. With scientific integrity at stake, further research with a similar study design should be conducted to determine the magnitude of this issue.

The use of systematic reviews for conducting new studies in physiotherapy research: a meta-research study comparing author guidelines of physiotherapy-related journals

BACKGROUND

Requiring authors to base their research on a systematic review of the existing literature prevents the generation of redundant scientific studies, thereby avoiding the deprivation of effective therapies for trial participants and the waste of research funds. Scientific medical journals could require this in their author guidelines. While this applies to all areas of research, it is also relevant to physiotherapy and rehabilitation research, which predominantly involve interventional trials in patients.

OBJECTIVE

The aim of this study was to determine the extent to which the use of systematic reviews to justify a new trial is already being requested by physiotherapy-related scientific medical journals (PTJs). In addition, a comparison was made between PTJs and scientific medical journals with the highest impact factor in the Science Citation Index Extended (SCIE).

METHODS

This meta-research study is based on a systematic examination of the author guidelines of 149 PTJs. The journals were identified and included based on the number of publications with physiotherapy as a keyword in the databases PEDro, and Medline (Pubmed). The included author guidelines were analysed for the extent to which they specified that a new trial should be justified by a systematic review of the literature. Additionally, they were compared with 14 scientific medical journals with the highest impact factor in the SCIE (LJs).

RESULTS

In their author guidelines, none of the included PTJs required or recommended the use of a systematic review to justify a new trial. Among LJs, four journals (28.57%), all associated with the Lancet group, required the study justification through a systematic review of the literature.

CONCLUSION

Neither PTJs nor LJs require or recommend the use of a systematic review to justify a new trial in their author guidelines. This potentially leaves room for unethical scientific practices and should be critically considered in future research.

Improving the reliability of measurements in orthopaedics and sports medicine

A large space still exists for improving the measurements used in orthopaedics and sports medicine, especially as we face rapid technological progress in devices used for diagnostic or patient monitoring purposes. For a specific measure to be valuable and applicable in clinical practice, its reliability must be established. Reliability refers to the extent to which measurements can be replicated, and three types of reliability can be distinguished: inter-rater, intra-rater, and test-retest. The present article aims to provide insights into reliability as one of the most important and relevant properties of measurement tools. It covers essential knowledge about the methods used in orthopaedics and sports medicine for reliability studies. From design to interpretation, this article guides readers through the reliability study process. It addresses crucial issues such as the number of raters needed, sample size calculation, and breaks between particular trials. Different statistical methods and tests are presented for determining reliability depending on the type of gathered data, with particular attention to the commonly used intraclass correlation coefficient.

Development of the INpaTiEnt Rehabilitation App Compliance QuesTionnaire [INTERACT]

BACKGROUND

The elements of previously designed questionnaires do not take into consideration the burdens encountered in an inpatient hospital setting. The purpose of this study is to validate elements of a non-compliance survey in an in-hospital setting and discuss aspects of compliance with telerehabilitative physiotherapy in the early postoperative period.

METHODS

A literature search was conducted to identify elements that prevent patients from performing their prescribed physical therapy exercises. These items were then evaluated by the expert review technique as described by Ikart. Afterwards, the synthesized survey was handed out to patients for the assessment of the quality of its items.

RESULTS

The results of the expert review technique identified some conceptual and grammatical problems. This led to the adjustment of some of the elements. The quality of the resulting questionnaire was deemed to be good, as patients were able to fully understand the concepts and answer accordingly. A statistical analysis was conducted to evaluate the responses.

CONCLUSIONS

The items of this second questionnaire have proven to be reliable to assess the compliance of patients in an in-hospital setting. These items will be added to the cross-culturally adapted items of a previous questionnaire.

Postoperative Activity and Knee Function of Patients after Total Knee Arthroplasty: A Sensor-Based Monitoring Study

Inertial measurement units (IMUs) are increasingly being used to assess knee function. The aim of the study was to record patients' activity levels and to detect new parameters for knee function in the early postoperative phase after TKA. Twenty patients (n = 20) were prospectively enrolled. Two sensors were attached to the affected leg. The data were recorded from the first day after TKA until discharge. Algorithms were developed for detecting steps, range of motion, horizontal, sitting and standing postures, as well as physical therapy. The mean number of steps increased from day 1 to discharge from 117.4 (SD ± 110.5) to 858.7 (SD ± 320.1), respectively. Patients' percentage of immobilization during daytime (6 a.m. to 8 p.m.) was 91.2% on day one and still 69.9% on the last day. Patients received daily continuous passive motion therapy (CPM) for a mean of 36.4 min (SD ± 8.2). The mean angular velocity at day 1 was 12.2 degrees per second (SD ± 4.4) and increased to 28.7 (SD ± 16.4) at discharge. This study shows that IMUs monitor patients' activity postoperatively well, and a wide range of interindividual motion patterns was observed. These sensors may allow the adjustment of physical exercise programs according to the patient's individual needs.

The S2e Guideline on Shoulder Stiffness

The clinical picture of "frozen shoulder" is still poorly understood. In order to present the current state of knowledge on aetiology, diagnosis, and treatment, and to provide recommendations for the professional groups involved, a working group was formed by the DGOU and the DVSE to create a German language, evidence-based guideline, which was published in 2022 by the AWMF. The following summarises the development and the most important results.

Non-Adherence with Physiotherapeutic Rehabilitation-A Cross-Cultural Adaption of Compliance Parameters into German

BACKGROUND

Compliance with rehabilitative physiotherapeutic measures leads to an improvement in outcomes in patients suffering from a variety of musculoskeletal conditions. To date, a tool for assessing the parameters that lead to non-adherence to physical therapy does not exist in the German language. The objective of this paper is to cross-culturally adapt a non-compliance questionnaire to German.

METHODS

In reference to the "Guidelines for the Process of Cross-Cultural Adaption of Self-Reported Measures", the questionnaire was translated into German followed by a back-translation into the original language. An expert committee met and refined the pre-final version. A preliminary version was handed out to patients for evaluation of the quality of the resulting German version.

RESULTS

After the forward- and back-translation of the questionnaire, some discrepancies were discovered between the translators on the one hand and between the back-translations and the original document on the other. The statistical analysis showed satisfactory results regarding the quality of the questionnaire.

CONCLUSION

The translation and adaption of the items proved to have a high degree of reliability. The German version will be made available for German-speaking researchers and used for evaluating a mobile-application-based physical therapy regimen by the authors of the paper.

Acetabular cup placement and offset control in robotic total hip arthroplasty performed through the modified anterolateral approach

PURPOSE

The modified anterolateral approach (Röttinger) for total hip arthroplasty (THA) offers great advantages over conventional approaches, especially concerning early postoperative symptoms, which are mild and well tolerated by patients. Robotic-assisted implantation might facilitate rapid adoption of the modified anterolateral approach without exposing surgeons to risks encountered during the learning curve. This study posits that the use of robotic assistance in conjunction with the modified anterolateral approach for total hip arthroplasty (THA) can provide a substantial enhancement in the accuracy of cup placement in comparison to manual surgery.

METHODS

Thirty-two robotic-assisted THAs met the inclusion criteria and were matched to 32 conventional cases. Acetabular cup inclination, anteversion, limb-length discrepancy, and acetabular offset were assessed using certified planning software by two independent observers using pre- and postoperative anterior-posterior radiographs. Data was analyzed for normal distribution. Chi2 test was used to determine whether implanted acetabular cups that were within Lewinnek's safe zones were influenced by type of implantation. Effect size estimates and statistical power analysis were also performed to appreciate the appropriateness of the chosen sample size.

RESULTS

Robotic-assisted implantation was found to significantly improve acetabular cup placement in terms of inclination (p < 0.001) but not anteversion (p = 0.783). Although mean postoperative limb-length discrepancy and mean acetabular offset did not differ between groups, a significantly smaller variance was found in the robotic-assisted group (p < 0.001) and (p = 0.04), respectively. There were no significant differences between the two groups in terms of consistently implanting the acetabular cup within the Lewinnek safe zones p = 0.641 for anteversion and p = 0.230 for inclination, respectively.

CONCLUSIONS

Our results show that although robotic-assisted acetabular cup implantation performed through the modified anterolateral approach did not significantly differ from conventional implantation, it did offer increased accuracy in cup positioning, acetabular bone preservation, and limb-length restoration.

High variation among clinical studies in the assessment of physical function after knee replacement: a systematic review

PURPOSE

The purpose of this study was to summarise the current use of outcome measures for the assessment of physical function after knee joint replacement.

METHODS

A systematic approach following the PRISMA guidelines was used. Literature search was performed on MEDLINE database via PubMed and on Epistemonikos. Clinical trials (level of evidence I-II) on knee joint replacement reporting data on the 'physical function' domain published between January 2017 and June 2022 were included. Descriptive statistics were used to summarise the evidence.

RESULTS

In the 181 articles that met the inclusion criteria, 49 different outcome measurements were used to evaluate clinical outcomes after knee joint replacement. The most frequently adopted patient-reported outcome measures (PROMs) were the Knee Society Score (KSS) (78 studies; 43.1%), the Western Ontario and McMaster Universities (WOMAC) Arthritis Index (62 studies; 34.3%), the Oxford Knee Score (OKS) (51 studies; 28.2%) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) (36 studies; 20%). The most frequently used performance-based outcome measures (PBOMs) were the Timed-Up-and-Go (TUG) test (30 studies; 16.6%) and the 6-min-walk test (6MWT) (21 studies; 11.6%). Among impairment-based outcome measures (IBOMs), range of motion (ROM) was the most used (74 studies; 40.9%).

CONCLUSION

There is considerable variation among clinical studies regarding the assessment of the physical function of patients after knee joint replacement. PROMs were found to be the most commonly adopted outcome measures; however, no single PROM was used in more than half of the papers analysed.

LEVEL OF EVIDENCE

Level II, systematic review of level I-II studies.

Determination of Relationships between Symmetry-Based, Performance-Based, and Functional Outcome Measures in Patients Undergoing Total Hip Arthroplasty

Due to the high heterogeneity in outcome measures after total hip arthroplasty (THA), the prospective observational study investigated the relationships between symmetry-based (SBMs), performance-based (PBMs), and functional outcome measures in THA patients to determine necessary or redundant categories of tests. The study material consisted of 24 patients with end-stage hip osteoarthritis scheduled for THA. The patients were examined one day before surgery and consecutively on the 4th day, 9th day, and 10th week postoperatively using the SBMs (weight-bearing chair-rising test, measurements of the maximal isometric torque of the quadriceps muscle); the PBMs (10-m walk, timed up-and-go, and stair-climbing tests); and the functional outcome measure (Harris Hip Score). The results obtained in a given category of tests at different time points were compared, and the correlations between the tests were determined. The reliability of the outcome measures was determined. The results of tests in the studied categories statistically significantly (p < 0.05) improved at the 10th week postoperatively compared to preoperative results. No strong correlations were revealed between the three studied types of outcome measures in THA patients. Therefore, none of them can be considered redundant. It also means that the relevance of symmetry for a core measurement set to describe the domain function in THA patients must be further clarified.

The role of SPECT/CT in painful, noninfected knees after knee arthroplasty: a systematic review and meta-analysis-a diagnostic test accuracy review

PURPOSE

The aim of this systematic review was to present the current evidence on the clinical use of single-photon emission computed tomography/computed tomography (SPECT/CT) in the evaluation of noninfected painful knees after knee arthroplasty.

METHODS

Embase, PubMed, Google Scholar, Ovid, Scopus, Science Direct and the Cochrane Database of Systematic Reviews were searched from database inception to May 2022 following the PRISMA guidelines. As a primary outcome, we defined the role of SPECT/CT in the diagnostic approach to noninfected painful knee arthroplasty; as a secondary objective, we described the noninfection-related factors linked to painful knee arthroplasty. Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio values and other indicators were calculated; receiver operating characteristic (ROC) curve analysis results and a summary of the areas under the curve (AUCs) from the included studies were reported. A Fagan plot, likelihood ratio plot and Deeks' funnel plot were generated and analysed. Methodological quality was assessed using the QUADAS-2 tool, and the certainty of evidence was assessed by the GRADE approach.

RESULTS

A total of 493 publications were identified, of which eight met the inclusion criteria, with a final pooled sample size of 308 patients. The pooled sensitivity and specificity of SPECT/CT in diagnosing the source of pain in painful knee prostheses were 0.86 (95% CI: 0.75-0.93) and 0.90 (95% CI: 0.79-0.96), respectively, with pooled +LR and -LR values of 8.9 (95% CI: 4.11-19.19) and 0.15 (95% CI: 0.09-0.28). The pooled diagnostic odds ratio was 57.35, and the area under the curve was 0.94. SPECT/CT highly accurately identified different sources of pain, such as loosening of the prosthetic components, patellofemoral overloading, instability, malalignment of the components and degeneration of the patellofemoral compartment. The confidence of the estimates was moderate according to the GRADE approach.

CONCLUSION

With demonstrated high sensitivity and specificity, as a diagnostic tool, SPECT/CT can identify the source of pain in painful knees after knee arthroplasty, particularly in cases of loosening, patellofemoral disorders and component malalignment (level of evidence III). These findings have significant clinical repercussions, such as in changing the initial diagnosis, identifying or excluding different causes of painful knee arthroplasties, guiding subsequent treatment and positively impacting the final clinical outcome. We moderately recommend the use of SPECT/CT for identifying the source of pain after knee arthroplasty according to the GRADE assessment. This review was preregistered in Prospero under code CRD42022320457.

Research designs and instruments to detect physiotherapy overuse of low-value care services in low back pain management: a scoping review

BACKGROUND

The provision of low-value physiotherapy services in low back pain management is a known but complex phenomenon. Thus, this scoping review aims to systematically map existing research designs and instruments of the field in order to discuss the current state of research methodologies and contextualize results to domains and perspectives of a referred low-value care typology. Ultimately, results will be illustrated and transferred to conditions of the German health care setting as care delivery conditions of physiotherapy in Germany face unique particularities.

METHODS

The development of this review is guided by the analysis framework of Arksey and O'Malley. A two-stage, audited search strategy was performed in Medline (PubMed), Web of Science, and google scholar. All types of observational studies were included. Identified articles needed to address a pre-determined population, concept, and context framework and had to be published in English or German language. The publication date of included articles was not subject to any limitation. The applied framework to assess the phenomenon of low-value physiotherapy services incorporated three domains (care effectiveness; care efficiency; patient alignment of care) and perspectives (provider; patient; society) of care.

RESULTS

Thirty-three articles met the inclusion criteria. Seventy-nine percent of articles focused on the appropriateness of physiotherapeutic treatments, followed by education and information (30%), the diagnostic process (15%), and goal-setting practice (12%). Study designs were predominantly cross-sectional (58%). Data sources were mainly survey instruments (67%) of which 50% were self-developed. Most studies addressed the effectiveness domain of care (73%) and the provider perspective (88%). The perspective of patient alignment was assessed by 6% of included articles. None of included articles assessed the society perspective. Four methodical approaches of included articles were rated to be transferrable to Germany.

CONCLUSION

Identified research on low-value physiotherapy care in low back pain management was widely unidimensional. Most articles focused on the effectiveness domain of care and investigated the provider perspective. Most measures were indirectly and did not monitor low-value care trends over a set period of time. Research on low-value physiotherapy care in secondary care conditions, such as Germany, was scarce.

REGISTRATION

This review has been registered on open science framework ( https://osf.io/vzq7k https://doi.org/10.17605/OSF.IO/PMF2G ).

Sensor-based telerehabilitation system increases patient adherence after knee surgery

OBJECTIVES

Implementing evidence-based recommendations with the option of patient-individualised and situation-specific adaptations in telerehabilitation may increase adherence with improved clinical outcome.

METHODS

As part of a registry-embedded hybrid design (part 1), digital medical device (DMD)-usage in a home-based setting was analysed in a multinational registry. The DMD combines an inertial motion-sensor system with instructions for exercises and functional tests on smartphones. A prospective, single-blinded, patient-controlled, multicentre intervention study (DRKS00023857) compared implementation capacity of the DMD to standard physiotherapy (part 2). Usage patterns by health care providers (HCP) were assessed (part 3).

RESULTS AND CONCLUSION

Registry raw data (10,311 measurements) were analysed from 604 DMD-users, demonstrating clinically expected rehabilitation progression post knee injuries. DMD-users performed tests for range-of-motion, coordination and strength/speed enabling insight to stage-specific rehabilitation (χ2 = 44.9, p<0.001). Intention-to-treat-analysis (part 2) revealed DMD-users to have significantly higher adherence to the rehabilitation intervention compared to the matched patient-control-group (86% [77-91] vs. 74% [68-82], p<0.05). DMD-users performed recommended exercises at home with higher intensity (p<0.05). HCP used DMD for clinical decision making. No adverse events related to the DMD were reported. Adherence to standard therapy recommendations can be increased using novel high quality DMD with high potential to improve clinical rehabilitation outcome, enabling evidence-based telerehabilitation.

Wrist motion assessment using Microsoft Azure Kinect DK: A reliability study in healthy individuals

BACKGROUND

Motion analysis systems have been widely used in orthopedics and rehabilitation for diagnostics, patient monitoring and outcome evaluation purposes. Since Microsoft Azure Kinect Developer Kit (DK) had been released, only a few studies were published concerning its usage. However, it has not been used for wrist motion assessments, even though the use of standardized examinations with known reliability, validity and responsiveness remains a constant challenge.

OBJECTIVES

This study aimed to examine the reliability of hand and forearm range of motion (ROM) measurements recorded using new software utilizing the Microsoft Azure Kinect DK.

MATERIAL AND METHODS

Twenty-eight healthy males and 28 healthy females participated in measurements of active ROM for wrist extension, wrist flexion, radial deviation, ulnar deviation, and forearm supination and pronation on 3 separate occasions. Sessions 1 and 2 were carried out on the same day with a 90-minute rest period between each session, while the 3rd session was conducted a week later. Data were recorded simultaneously in both limbs using a custom-made software developed by a software development company (Oleksy Medical & Sports Sciences, Łańcut, Poland) for the purposes of the present study using Microsoft Azure Kinect DK. The assessment of intra-day and inter-day reliability was based on intraclass correlation coefficient (ICC) calculations and interpreted based on commonly used guidelines.

RESULTS

In the group of males, the lowest ICC was 0.846 for intra-day comparisons and 0.816 for inter-day analyses. In the female group, the lowest ICC for intra-day comparisons was 0.826 and exceeded 0.833 for inter-day comparisons.

CONCLUSIONS

The developed software using Microsoft Azure Kinect DK demonstrated high reliability in measuring wrist and forearm active ROM. These promising results support the use of Microsoft Azure Kinect DK in a clinical capacity as a potential hand assessment and rehabilitation tool.

The Patellostabilometer: A New Device for Quantification of Mediolateral Patella Displacement

Mediolateral patella displacement is of interest for diagnostics and clinically relevant research questions. Apart from manual testing, no standardized method is currently available. Proper quantification of patella mobility is necessary to better understand pathologies at the patellofemoral joint. Patella mobility was assessed in 25 healthy individuals using a Patellostabilometer, a new prototype instrument for quantification of the mediolateral patella displacement. The participants underwent measurements of the mediolateral displacement three times using the Patellostabilometer. A maximal force of 10 N was applied for patella movement. Additionally, leg length and circumference of the knee, upper- and lower-leg were measured. Lateral patella displacement of 18.27 ± 3.76 mm (range 15.85-20.64 mm, interquartile range (IQR) of 4.79) was measured. The medial patella displacement showed 24.47 ± 6.59 mm (range 19.29-29.76 mm, IQR of 10.47). The test-retest measurement error was 2.32 ± 1.76 mm (IQR of 2.38 mm), with five outliers. There was greater test-retest variability between the measurements of the medial displacement compared to the lateral one. The test-retest variability reached 7% of the patella displacement. Other parameters provided no significant correlations. Based on the natural patellofemoral mobility, a precise and clinically relevant quantification of patella mobility is allowed.

A Randomized, Double-Blind Placebo Control Study on the Effect of a Blood Flow Restriction by an Inflatable Cuff Worn around the Arm on the Wrist Joint Position Sense in Healthy Recreational Athletes

The number of blood flow restriction (BFR) training practitioners is rapidly increasing, so understanding the safety issues associated with limb occlusion is strongly needed. The present study determined the effect of BFR by an inflatable cuff worn around the arm on the wrist joint position sense (JPS) in healthy recreational athletes. In the prospective randomized, double-blind placebo control study, sixty healthy right-handed recreational athletes aged x = 22.93 ± 1.26 years were assigned to groups of equal size and gender rates: BFR, placebo, and control. The active wrist JPS was assessed in two separate sessions using an isokinetic dynamometer. The first assessment was performed with no cuffs. In the second session, a cuff with a standardized pressure was worn on the examined limb in the BFR group. In the placebo group, the cuff was uninflated. A between-session comparison in each group of collected angular errors expressed in degrees was carried out. The angular error in the BFR group was larger during the second measurement than the first one (p = 0.011-0.336). On the contrary, in the placebo (p = 0.241-0.948) and control (p = 0.093-0.904) groups, the error value in the second session was comparable or smaller. It was determined that BFR by an inflatable cuff around the arm impairs the wrist position sense. Hence, BFR training should be performed with caution.

A Pilot Study on the Reliability of Ultrasound-Based Assessment of Patella Diameter and Sulcus Angle

This pilot study aimed to determine the reliability of a newly developed ultrasound-based protocol for the assessment of patella diameter and sulcus angle. The diameter of the patella expressed in mm and the sulcus angle, expressed in degrees were measured in the right knee in 12 healthy participants (eight women and four men) in two separate sessions by two examiners (experienced rater and inexperienced rater) using ultrasonography according to a developed standardized protocol. The reliability was determined on the calculated intraclass correlation coefficient, ICC, expressed as a 95% confidence interval (lower bound, upper bound). For the patella diameter measurement, intra-rater and inter-rater reliability were good to excellent, with the ICC exceeding 0.836-0.998 and 0.859-0.997, respectively. The intra-rater and inter-rater reliability of the sulcus measurement was moderate to excellent, as the ICC amounted to 0.559-0.993 and 0.559-0.990, respectively. The reliability of both measures increased with the experience of the examiner. Therefore, it was determined that the newly developed protocol for an ultrasound-based assessment of patella diameter and sulcus angle is reliable. Further studies validating their clinical use should be carried out.

Effects of physiotherapy interventions for home-based rehabilitation on physical function after primary total knee arthroplasty: a systematic review protocol

OBJECTIVE

The objective of this review is to provide a systematic and transparent overview of the effects of common physiotherapy techniques and exercises for the rehabilitation of patients following total knee arthroplasty.

INTRODUCTION

Many protocols exist for the rehabilitation of patients after total knee arthroplasty, but there is a lack of systematic evidence on rehabilitation components, including precise exercise descriptions and their parameters. This review will fill in some of the gaps in reporting on scientific rehabilitation protocol components and the evaluation of their effectiveness.

INCLUSION CRITERIA

We will include randomized controlled trials investigating active and passive physiotherapy techniques and exercises employed after primary total knee arthroplasty, and which report concrete parameters, such as dosage, duration, frequency, intensity, and function-related measurements. We will exclude other study types and randomized controlled trials reporting on techniques and exercises without precise descriptions.

METHODS

This review will aim to find both published and unpublished studies. The key information sources to be searched are MEDLINE (PubMed), Embase (Ovid), CINAHL (EBSCO), PEDro, Cochrane CENTRAL, ClinicalTrials.gov, and WHO International Clinical Trials Registry Platform. Two independent reviewers will screen titles, abstracts, and full texts; assess the methodological quality; and extract the data. We will perform narrative synthesis, followed by meta-analyses for pooled studies, where possible.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022309185.

Knee Orthotics Do Not Influence Coordinative Skills—A Randomized Controlled Crossover Pilot Trial

Objective: This single-blind randomized controlled crossover pilot trial investigated whether hard or soft knee orthotics affect the back in action (BIA) test battery performance. Methods: Twenty-four healthy participants (13 males, 11 females) were randomly assigned into three equal groups differentiated through the order of device use. The data were collected in a laboratory setting. BIA test battery (balance tests, vertical jumps, and parkour hop tests) was run with a rigid orthotic device, a soft brace, or no aid in a crossover order. Analysis of Variance repeated measures and Friedman Test were used to calculate depended-group differences. Results: No significant or clinically relevant effect or differences was observed between running the BIA with a soft brace, rigid orthosis, or no aid (p = 0.53–0.97) for all included tests. No adverse events have been observed. Conclusion: Soft and rigid knee braces do not affect performance in healthy participants. Missing experience with the devices might explain a few influences on feedback mechanisms. There is no disadvantage to be expected regarding healthy participants running back to sports.

No correlation between symmetry-based performance measures and patient-related outcome prior to and after total knee arthroplasty

PURPOSE

Standardized outcome measures are crucial for the evaluation of different treatment and rehabilitation regimes in patients after total knee arthroplasty (TKA). Performance-based measures are necessary to capture different aspects of physical function. High reliability and agreement of five performance-based measures were hypothesized to differentiate between measurement error and change in test performance. Secondary outcomes are the correlation of performance-based measurements to KSS and WOMAC prior to surgery (baseline) and 10 weeks thereafter (t3).

METHODS

The test-retest reliabilities and agreements of the 1-m walk test, the stair-climbing test, the timed-up-and-go test, the weight-balanced-chair-rising test and the isometric maximum knee extension force in patients undergoing total knee replacements were studied. The intraclass correlation coefficient was calculated and a Bland-Altman analysis performed.

RESULTS

The weight-balanced-chair-rising test showed a symmetry at baseline = 0.77, 5 ± 1 days after surgery (t1) = 0.50, 9 ± 1 days (t2) = 0.59 and (t3) = 0.80. All performance tests showed high intraclass correlation coefficients (ICC = 0.81-0.99). The 10-m walk test, stair climbing test, and the timed-up-and-go test showed high agreement in the Bland-Altman analysis. The Bland-Altman analysis for the weight-balanced-chair-rising test and isometric knee extension force indicated high agreement at 5 and 9 days postoperatively, but the relative measurement error increased pre- and 10 weeks postoperatively.

CONCLUSION

In conclusion, symmetry, as an important outcome after TKA, is a reliable and rather unique item that should unquestionably be added to established measurements like walking tests or survey-based function assessment. The implementation of standardized performance-based measures to assess physical function in rehabilitation procedures will help to improve the more objectively based assessment of different rehabilitation protocols.

LEVEL OF EVIDENCE

II.

The influence of gluteal muscle strength deficits on dynamic knee valgus: a scoping review

Anterior cruciate ligament (ACL) injuries are caused by both contact and non-contact injuries. However, it can be claimed that non-contact ones account approximately for 70% of all cases. Thus, several authors have emphasized the role of reduction of muscle strength as a modifiable risk factor referred to non-contact ACL injury, with the latter being targeted by specific training interventions.The present paper wants to review the available literature specifically on the relationship between dynamic knee valgus, gluteal muscles (GM) strength, apart from the potential correlation regarding ACL injury.After a research based on MEDLINE via PubMed, Google scholar, and Web of Science, a total of 29 articles were collected and thus included.Additionally, this review highlights the crucial role of gluteal muscles in maintaining a correct knee position in the coronal plane during different exercises, namely walking, running, jumping and landing.

Reporting and transparent research practices in sports medicine and orthopaedic clinical trials: a meta-research study

OBJECTIVES

Transparent reporting of clinical trials is essential to assess the risk of bias and translate research findings into clinical practice. While existing studies have shown that deficiencies are common, detailed empirical and field-specific data are scarce. Therefore, this study aimed to examine current clinical trial reporting and transparent research practices in sports medicine and orthopaedics.

SETTING

Exploratory meta-research study on reporting quality and transparent research practices in orthopaedics and sports medicine clinical trials.

PARTICIPANTS

The sample included clinical trials published in the top 25% of sports medicine and orthopaedics journals over 9 months.

PRIMARY AND SECONDARY OUTCOME MEASURES

Two independent reviewers assessed pre-registration, open data and criteria related to scientific rigour, like randomisation, blinding, and sample size calculations, as well as the study sample, and data analysis.

RESULTS

The sample included 163 clinical trials from 27 journals. While the majority of trials mentioned rigour criteria, essential details were often missing. Sixty per cent (95% confidence interval (CI) 53% to 68%) of trials reported sample size calculations, but only 32% (95% CI 25% to 39%) justified the expected effect size. Few trials indicated the blinding status of all main stakeholders (4%; 95% CI 1% to 7%). Only 18% (95% CI 12% to 24%) included information on randomisation type, method and concealed allocation. Most trials reported participants' sex/gender (95%; 95% CI 92% to 98%) and information on inclusion and exclusion criteria (78%; 95% CI 72% to 84%). Only 20% (95% CI 14% to 26%) of trials were pre-registered. No trials deposited data in open repositories.

CONCLUSIONS

These results will aid the sports medicine and orthopaedics community in developing tailored interventions to improve reporting. While authors typically mention blinding, randomisation and other factors, essential details are often missing. Greater acceptance of open science practices, like pre-registration and open data, is needed. As these practices have been widely encouraged, we discuss systemic interventions that may improve clinical trial reporting.

Increase in cartilage degeneration in all knee compartments after failed ACL reconstruction at 4 years of follow-up

Purpose

Degeneration of the cartilage after anterior cruciate ligament reconstruction (ACL-R) is known, and further deterioration can be expected in patients with tunnel malplacement or partial meniscal resection. It was hypothesized that there is a significant increase in cartilage degeneration after failed ACL-R.

Material and methods

Isolated ACL revision surgery was performed in 154 patients at an interval of 46 ± 33 months (5–175 months) between primary and revision surgery. Cartilage status at the medial, lateral femorotibial, and patellofemoral compartments were assessed arthroscopically during primary and revision ACL-R in accordance with the Outerbridge classification. Tunnel placement, roof angle, and tibial slope was measured using anteroposterior and lateral radiographic views.

Results

Cartilage degeneration increased significantly in the medial femorotibial compartment, followed by the lateral and patellofemoral compartments. There was a correlation between both cartilage degeneration in the patellofemoral compartment (PFC) (r_s = 0.28, p = 0.0012) and medial tibial plateau (R_s = 0.24, p = 0.003) in relation to the position of tibial tunnel in the frontal plane. Worsening of the cartilage status in the medial femorotibial compartment, either femoral or tibial, was correlated with the tibial aperture site in the lateral view (R_s = 0.28, p < 0.001). Cartilage degeneration in the lateral compartment of the knee, on both femoral or tibial side, was inversely correlated with the femoral roof angle (R_s = −0.1985, p = 0.02). Meniscal tears, either at the medial or lateral site or at both, were found in 93 patients (60%) during primary ACL-R and increased to 132 patients (86%) during revision ACL-R.

Discussion

Accelerated cartilage degeneration and high prevalence of meniscal lesions are seen in failed ACL-R. Tunnel placement showed significant impact on cartilage degeneration and may partially explain the increased risk of an inferior outcome when revision surgery is required after failed primary ACL-R.

Level of evidence: Level IV—retrospective cohort study.

A Systematic Review of Diagnostic Accuracy and Clinical Applications of Wearable Movement Sensors for Knee Joint Rehabilitation

In clinical practice, only a few reliable measurement instruments are available for monitoring knee joint rehabilitation. Advances to replace motion capturing with sensor data measurement have been made in the last years. Thus, a systematic review of the literature was performed, focusing on the implementation, diagnostic accuracy, and facilitators and barriers of integrating wearable sensor technology in clinical practices based on a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. For critical appraisal, the COSMIN Risk of Bias tool for reliability and measurement of error was used. PUBMED, Prospero, Cochrane database, and EMBASE were searched for eligible studies. Six studies reporting reliability aspects in using wearable sensor technology at any point after knee surgery in humans were included. All studies reported excellent results with high reliability coefficients, high limits of agreement, or a few detectable errors. They used different or partly inappropriate methods for estimating reliability or missed reporting essential information. Therefore, a moderate risk of bias must be considered. Further quality criterion studies in clinical settings are needed to synthesize the evidence for providing transparent recommendations for the clinical use of wearable movement sensors in knee joint rehabilitation.

Author guidelines for conducting systematic reviews and meta-analyses

This article is a guidance how to write systematic reviews (SR's) and meta-analyses (MA) in orthopaedics and which aspects to focus on for transparency, systematicity and readability. Both SR and MA summarise and synthesise the best evidence available on a specific topic. This requires a systematic, structured and transparent process of analysis. The title should be concise, indicate type of review and ideally report the most important finding. Next, the structured abstract (no more than 350 words) should also raise key points and report the overall level of evidence. A relevant clinical question must be defined before the literature search is started. Methodological details such as databases searched, the exact search strategy (including time frame), inclusion/exclusion criteria, method of literature appraisal and statistical analysis must be described briefly. The primary and secondary outcomes should be mentioned. SR's be pre-registered before data extraction, to ensure transparency and the reduction of risk of bias. If registered, registration number should be stated in the abstract and the funding sources. A clear summary of the findings is important including the number of identified studies (depicted in a flowchart) and for meta-analyses a forest plot. The results of the literature appraisal and statistical analyses should be reported precisely. Subsequently, a general interpretation of findings and their significance and relevance to clinical practice should be provided. Clinical implications from the analysis should be drawn carefully and further research questions should be addressed. Finally, a conclusion, based solely on the results of the study is a necessity. Up to ten keywords are requested representing the main content of the article. Most applicable keywords should facilitate finding the manuscript in the databases and therefor considered carefully.

Joint effusion, anteroposterior stability, muscle strength and degree of patellofemoral osteoarthritis significantly impact outcome following revision ACL reconstruction

PURPOSE

Effusion, impaired muscle function and knee instability are considered as some of the most important factors effecting outcome following anterior cruciate ligament reconstruction (ACL-R) but the impact on revision ACL-R remains unclear. It was hypothesized that these factors will significantly worsen clinical outcome following revision ACL-R.

METHODS

Seventy knees (13 female and 57 male) were followed retrospectively after revision ACL-R at a mean follow-up of 47.8 ± 20.7 months. Clinical examination was based on the International Knee Documentation Evaluation Form-2000 (IKDC), Tegner activity scale. Instrumented measurement of anterior tibial translation was performed using the Rolimeter® (DJO Global, Freiburg, Germany). Bilateral circumference of the thigh was measured 10 and 20 cm proximal to the medial joint space. Cartilage was assessed according to Outerbridge classification during both primary and revision ACL-R.

RESULTS

Tegner activity scale decreased significantly from 7.8 ± 1.4 points at primary ACL-R to 7 ± 1.8 points at revision ACL-R, and 5.8 ± 1.7 points at the time of follow up (p < 0.001). Joint effusion (r = - 0.47, p < 0.01) and side to side differences in single leg hop test (r = - 0.48, p < 0.1) significantly correlated with inferior outcome. Cartilage lesions were found in 67% of the patients at the time of revision ACL-R compared to 38% at the time of primary ACL-R. According to the IKDC classification A was graded in three patients (4.3%), B in 35 (50%), C in 29 (41.4%) and D in three (4.3%). Joint effusion was measured in 35% of patients at the time of follow-up. Degeneration at the patellofemoral compartment of > grad 2 was responsible for IKDC grade C and D (p = 0.035). Instrumented anteroposterior site-to-site difference of ≥3 mm showed significant impact on clinical outcome (p < 0.019).

CONCLUSION

The study has shown that chronic effusion, quadriceps dysfunction, cartilage lesions especially at the patellofemoral compartment and side to side difference in anteroposterior stability significantly influences patient outcome after revision ACL-R. These factors require special attention when predicting patient's outcome.

LEVEL OF EVIDENCE

Level-IV, case-controlled study.

Digital Health Transition in Rheumatology: A Qualitative Study

The global COVID-19 pandemic has led to drastic changes in the management of patients with rheumatic diseases. Due to the imminent risk of infection, monitoring intervals of rheumatic patients have prolonged. The aim of this study is to present insights from patients, rheumatologists, and digital product developers on the ongoing digital health transition in rheumatology. A qualitative and participatory semi-structured fishbowl approach was conducted to gain detailed insights from a total of 476 participants. The main findings show that digital health and remote care are generally welcomed by the participants. Five key themes emerged from the qualitative content analysis: (1) digital rheumatology use cases, (2) user descriptions, (3) adaptation to different environments of rheumatology care, and (4) potentials of and (5) barriers to digital rheumatology implementation. Codes were scaled by positive and negative ratings as well as on micro, meso, and macro levels. A main recommendation resulting from the insights is that both patients and rheumatologists need more information and education to successfully implement digital health tools into clinical routine.

Patient, physiotherapist and surgeon endorsement of the core domain set for total hip and total knee replacement in Germany: a study protocol for an OMERACT initiative

INTRODUCTION

There is a lack of harmonising measures for clinical trials on total joint replacement (TJR) that would allow for results from TJR studies to be compared or pooled. The Outcome Measures in Rheumatology (OMERACT) TJR core domain set is already endorsed among patients and physicians in the USA and Australia. Physiotherapists use different types of measurements compared to orthopaedic surgeons while both make substantial contributions to research in the field of TJR. To achieve consensus on core measurements sets, patients, physiotherapists and orthopaedic surgeons need to achieve consensus on the core domains for TJR trials.

METHODS AND ANALYSIS

For this multistage study, first, the OMERACT TJR core domain set survey will be translated to German and validated according to WHO guidelines. Next, the TJR core domain set will be considered for endorsement in different German stakeholder groups including patients, physiotherapists and orthopaedic surgeons.

ETHICS AND DISSEMINATION

Ethical approval for this protocol was given by the ethics committee of the Brandenburg University of Technology Cottbus-Senftenberg (BTU-CS, EK 2019-2). This article is based on the protocol version 2.5 from 6 May 2020. Anonymous data will be presented only. We will publish the results in peer-reviewed publications and at international conferences.

TRIAL REGISTRATION NUMBER

German Clinical Trials Registry (DRKS00016015).

Body Composition and Strength Parameters in Elite Judo Athletes 5 Years after Anterior Cruciate Ligament Reconstruction

The purpose of this study was to investigate if there are still deficits in muscle mass or strength capabilities in elite judo athletes with a history of anterior cruciate ligament reconstruction (ACLR) after their return to the sport. Therefore, bioimpedance analysis, 3D-laser thigh circumference measurement and isokinetic dynamometry in a closed kinetic chain were used. The side-to-side differences were investigated in a group of judo athletes 5 years after ACLR (n=17) and compared with a group of healthy judo athletes (n=27). Neither thigh circumferences, nor muscle masses of the lower extremities differed in formerly injured judo athletes compared to healthy judo athletes. In contrast, isokinetic strength testing showed a significantly larger side-to-side difference of peak muscle force in formerly injured judo athletes (p=0.021). They provided significantly lower peak forces with the formerly injured leg than with the non-injured leg (p<0.001). The authors conclude that strength capabilities, but not body composition, remains altered in recovered judo athletes in mean 5 years after ACLR and definitely after their return to sports. This indicates that the focus of rehabilitation protocols and return to sports assessments should focus more on maximum strength capabilities.

Associations between classroom CO2 concentrations and student attendance in Washington and Idaho

Student attendance in American public schools is a critical factor in securing limited operational funding. Student and teacher attendance influence academic performance. Limited data exist on indoor air and environmental quality (IEQ) in schools, and how IEQ affects attendance, health, or performance. This study explored the association of student absence with measures of indoor minus outdoor carbon dioxide concentration (dCO(2)). Absence and dCO(2) data were collected from 409 traditional and 25 portable classrooms from 22 schools located in six school districts in the states of Washington and Idaho. Study classrooms had individual heating, ventilation, and air conditioning (HVAC) systems, except two classrooms without mechanical ventilation. Classroom attributes, student attendance and school-level ethnicity, gender, and socioeconomic status (SES) were included in multivariate modeling. Forty-five percent of classrooms studied had short-term indoor CO(2) concentrations above 1000 p.p.m. A 1000 p.p.m. increase in dCO(2) was associated (P < 0.05) with a 0.5-0.9% decrease in annual average daily attendance (ADA), corresponding to a relative 10-20% increase in student absence. Annual ADA was 2% higher (P < 0.0001) in traditional than in portable classrooms.

PRACTICAL IMPLICATIONS

This study provides motivation for larger school studies to investigate associations of student attendance, and occupant health and student performance, with longer term indoor minus outdoor CO(2) concentrations and more accurately measured ventilation rates. If our findings are confirmed, improving classroom ventilation should be considered a practical means of reducing student absence. Adequate or enhanced ventilation may be achieved, for example, with educational training programs for teachers and facilities staff on ventilation system operation and maintenance. Also, technological interventions such as improved automated control systems could provide continuous ventilation during occupied times, regardless of occupant thermal comfort demands.

Mapping the ribonucleolytic active site of eosinophil-derived neurotoxin (EDN). High resolution crystal structures of EDN complexes with adenylic nucleotide inhibitors

Eosinophil-derived neurotoxin (EDN), a basic ribonuclease found in the large specific granules of eosinophils, belongs to the pancreatic RNase A family. Although its physiological function is still unclear, it has been shown that EDN is a neurotoxin capable of inducing the Gordon phenomenon in rabbits. EDN is also a potent helminthotoxin and can mediate antiviral activity of eosinophils against isolated virions of the respiratory syncytial virus. EDN is a catalytically efficient RNase sharing similar substrate specificity with pancreatic RNase A with its ribonucleolytic activity being absolutely essential for its neurotoxic, helminthotoxic, and antiviral activities. The crystal structure of recombinant human EDN in the unliganded form has been determined previously (Mosimann, S. C., Newton, D. L., Youle, R. J., and James, M. N. G. (1996) J. Mol. Biol. 260, 540-552). We have now determined high resolution (1.8 A) crystal structures for EDN in complex with adenosine-3',5'-diphosphate (3',5'-ADP), adenosine-2',5'-di-phosphate (2',5'-ADP), adenosine-5'-diphosphate (5'-ADP) as well as for a native structure in the presence of sulfate refined at 1.6 A. The inhibition constant of these mononucleotides for EDN has been determined. The structures present the first detailed picture of differences between EDN and RNase A in substrate recognition at the ribonucleolytic active site. They also provide a starting point for the design of tight-binding inhibitors, which may be used to restrain the RNase activity of EDN.

Acute effects of the skeletal muscle-specific immunotoxin ricin-mAb 35 on extraocular muscles of rabbits

PURPOSE

To determine the acute histologic and ultrastructural effects of a recently developed muscle-specific immunotoxin, ricin-mAb 35.

METHODS

Graduated doses of ricin-mAb 35, composed of ricin conjugated to a monoclonal antibody against the nicotinic acetylcholine receptor of skeletal muscle, were injected into one superior rectus muscle in rabbits. After 3, 7, and 14 days, both superior rectus muscles were removed and prepared for electron microscopy and histologic examination, by using a number of immunohistochemical markers to identify inflammatory cell infiltration, muscle fiber loss, and muscle regeneration.

RESULTS

Myotoxicity of the ricin-mAb 35 was focal and dose related. At the highest dose tested, there was substantial inflammatory cell infiltrate by 3 days, which largely disappeared by 7 days. Significant muscle loss was apparent by 7 days after ricin-mAb 35 treatment. Both the inflammatory reaction and muscle fiber loss were confined to the immediate injection site. Surrounding muscle appeared to be normal. At 14 days after treatment, early signs of muscle regeneration were evident within the tissue sections. No evidence of orbital or systemic toxicity was seen in any animal.

CONCLUSIONS

Direct injection of ricin-mAb 35 into the extraocular muscles of rabbits results in a dose-related focal injury to the muscles, with a self-limited inflammatory component and significant muscle fiber loss. This novel immunotoxin may be useful in the treatment of strabismus if chronic studies show a sustained histologic and electrophysiologic effect.