Nuclear magnetic resonance diffraction with subangstrom precision.

We have combined ultrasensitive force-based spin detection with high-fidelity spin control to achieve NMR diffraction (NMRd) measurement of ~2 million [Formula: see text]P spins in a [Formula: see text] volume of an indium-phosphide (InP) nanowire. NMRd is a technique originally proposed for studying the structure of periodic arrangements of spins, with complete access to the spectroscopic capabilities of NMR. We describe two experiments that realize NMRd detection with subangstrom precision. In the first experiment, we encode a nanometer-scale spatial modulation of the z-axis magnetization of [Formula: see text]P spins and detect the period and position of the modulation with a precision of <0.8 Å. In the second experiment, we demonstrate an interferometric technique, utilizing NMRd, to detect an angstrom-scale displacement of the InP sample with a precision of 0.07 Å. The diffraction-based techniques developed in this work extend the Fourier-encoding capabilities of NMR to the angstrom scale and demonstrate the potential of NMRd as a tool for probing the structure and dynamics of nanocrystalline materials.

Evaluation of the standard procedure for treatment of periprosthetic joint infections of total knee and hip arthroplasty: a comparison of the 2015 and 2020 census in total joint replacement centres in Germany.

BACKGROUND: There are different procedures for both, the diagnosis and the therapy of a periprosthetic joint infection (PJI), however, national or international guidelines for a standardised treatment regime are still lacking. The present paper evaluates the use of the predominant treatment protocols for PJI in certified total joint replacement centres (EPZ) in Germany based on an EndoCert questionnaire. MATERIALS AND METHODS: The questionnaire was developed in cooperation with the EndoCert Certification Commission to survey the treatment protocols for septic revision arthroplasties in EPZ. Questions targeted the various treatment options including prosthesis preserving procedures (DAIR - Debridement, antibiotics, irrigation, and retention of the prosthesis), one-stage revision, two-stage revision, removal of the endoprosthesis and diagnostic sampling prior to re-implantation. All certified EPZ participated (n = 504) and the results from the current survey in 2020 were compared to data from a previous analysis in 2015. RESULTS: The number of centres that performed DAIR up to a maximum of 4 weeks and more than 10 weeks after index surgery decreased since 2015, while the number of centres that provided a one-stage revision as a treatment option increased (hip: + 6.3%; knee: + 6.6%). The majority of the centres (73.2%) indicated a 4-8 week period as the preferred interval between prosthesis removal and re-implantation in two-stage revision in hip as well as knee revisions. Centres with a higher number of revision surgeries (> 200 revisions/year), opted even more often for the 4-8 week period (92.3%). In two-stage revision the use of metal-based spacers with/without reinforcement with antibiotic-containing cement as an interim placeholder was significantly reduced in 2020 compared to 2015. There was also a clear preference for cemented anchoring in two-stage revision arthroplasty in the knee in 2020, whereas the majority of hip replacements was cementless. Additionally, in 2020 the number of samples for microbiological testing during the removal of the infected endoprosthesis increased and 72% of the centres took five or more samples. Overall, the number of EPZ with a standardised protocol for the procedure expanded from 2015 to 2020. CONCLUSION: While there was a trend towards standardised therapeutic algorithms for PJI with more uniform choices among the centres in 2020 compared to 2015, the treatment often remains an individual decision. However, since a consistent treatment regime is of vital importance with an expected rise of total numbers of revision arthroplasties, uniform definitions with regard to comparability and standardisation are necessary for the further development of the EndoCert system.

Evaluation of the standard procedure for the treatment of periprosthetic joint infections (PJI) in Germany - results of a survey within the EndoCert initiative.

BACKGROUND: The periprosthetic joint infection (PJI) is a severe complication in the field of arthroplasty. Despite the rising number of primary joint replacements, no unified therapeutic standard has been established for the treatment of PJI yet. METHODS: A survey on the principles of treatment of PJI in Germany was conducted. A total of 515 EndoProthetikZentren (EPZ) were included, resulting in a response rate of 100%. RESULTS: For early infections 97.6% of the centers use prosthesis-preserving procedures (DAIR). A one-stage exchange was implemented by less than 50% of the centers. If implemented, this treatment entails a prior selection of patients for a successful treatment. The two-stage exchange is performed in all centers, and most centers proceed with the implantation of a cemented spacer between stages. 75% of the centers proceed with a center-based concept for the treatment of PJI. CONCLUSION: The aim of a uniform PJI standard at the centers has not yet been fully achieved. Further improvements within the certification were initiated. The most relevant treatment options in Germany are displayed. The two-stage revision with a cemented spacer is the most widely implemented treatment. This exposition of principles could help for the further development of standardized treatment guidelines and definitions.

Fixation Stability of Uncemented Acetabular Cups With Respect to Different Bone Defect Sizes.

BACKGROUND: In total hip arthroplasty, acetabular press-fit cups require a proper bone stock for sufficient primary implant fixation. The presence of acetabular bone defects compromises the primary fixation stability of acetabular press-fit cups. The aim of the present study is to determine the fixation stability of a cementless acetabular cup regarding standardized bone defects in an experimental setup. METHODS: An acetabular defect model was developed and transferred to a biomechanical cup-block model. The lack of superior cup coverage was divided into 4 stages of superior rim loss (33%, 50%, 67%, and 83%) in the anterior-posterior direction and into 4 stages of mediolateral wall absence (11%, 22%, 33%, and 50%). This resulted in 11 different defect cavities, which were compared to the intact cavity in push-in and lever-out tests of one press-fit cup design (56 mm outer diameter). Thereby, push-in force, lever-out moment, lever-out angle, and interface stiffness were determined. RESULTS: The determined lever-out moments range from 15.53 ± 1.38 Nm (intact cavity) to 1.37 ± 0.54 Nm (83%/50% defect). Smaller defects (33%/11%, 33%/22%, and 50%/11%) reduce the lever-out moments by an average of 33.9% ± 2.8%. CONCLUSION: The lack of mediolateral acetabular coverage of 50% was assessed as critical for cementless cup fixation, whereby the contact zone between implant and bone in the defect is lost. A lack of 20% to 30% mediolateral coverage appears to be acceptable for press-fit cup fixation in the presence of primary stability. A defect of 50%/50% was identified as the threshold for using additional fixation methods.

[Very rare cases of periprosthetic malignant neoplasms : Data from 4000 cases of endoprosthetic joint replacements from the histopathologic implant register]. / Nachweis hoch seltener periprothetischer maligner Neoplasien : Ergebnisse von 4000 Gelenkendoprothesen aus dem histopathologischen Implantatregister.

BACKGROUND: In 2016, the AG 11 (work group for implant-material-intolerance) of the German society for Orthopaedics and Orthopaedic Surgery (DGOOC) created a histopathologic implant register (HIR). The goal was to conduct a retrospective data analysis based on the revised SLIM-consensus-classification, which defines eight different failure mechanisms. QUESTIONS: The analysis of 4000 cases of endoprosthetic joint replacements addressed the following questions: 1. What is the frequency distribution of different SLIM-types? 2. How does durability of endoprosthetic joint replacements differ among SLIM-types? 3. What kind of periprosthetic malignant neoplasia can be detected and how often? RESULTS: SLIM-type I was diagnosed in 1577 cases (n = 1577, 39.4%), SLIM-type II in 577 cases (n = 577; 14.4%), SLIM-type III in 146 cases (n = 146; 3,7%), SLIM-type IV in 1151 cases (n = 1151; 28.8%), SLIM-type V in 361 cases (n = 361; 9.0%), SLIM-type VI in 143 cases (n = 143; 3.6%), SLIM-type VII in 42 cases (n = 42; 1.0%), and SLIM-type VIII in 3 cases (n = 3; 0.075%). There was statistical significance in implant durability between the different SLIM types. Among the different reasons for endoprosthetic joint replacement failure, non-infectious causes have the biggest share at 81%, with SLIM-type I (39.5%), and SLIM-type IV (29.4%) being the predominant SLIM types. Three cases of periprosthetic malignant neoplasia (SLIM-type VIII) were detected: one case of small B lymphocytic lymphoma/BCLL (C85.9; ICD-O: 9670/3), one case of diffuse large B­cell lymphoma/DLBCL (C83.3; ICD­O 9680/3), and one case of anaplastic large cell lymphoma (C84.7; ICD-O: 9714/3), with the latter ones being the causes for joint replacement , which indicates that malignant neoplasia is a very rare cause of endoprosthetic joint replacement (n = 2; 0.05%). DISCUSSION: These data are complete new, especially as concerns arthrofibrosis (SLIM-type V), adverse inflammatory reactions (SLIM-type VI), and the very rare cases of periprosthetic malignant neoplasia, SLIM-type VIII, as a reason for revision. Since neither the annual review (2017) of the EPRD, nor the national evaluation report (2017) of the IQTIG provide sufficient data, this indicates the relevance of the HIR of the AG 11 of the DGOOC.

[Three-year revision rate of certified centres for joint replacement according to EndoCert : Risk-adjusted analysis of outcome quality and comparison with other quality assurance systems]. / 3-Jahres-Revisionsrate von zertifizierten EndoProthetikZentren nach EndoCert : Risikoadjustierte Analyse der Ergebnisqualität und Vergleich mit anderen Qualitätssicherungssystemen.

BACKGROUND: The EndoCert initiative does not yet allow a long-term assessment of outcome quality. The assessment cannot be achieved without cooperation with the German arthroplasty registry (EPRD) and other quality assurance infrastructure, such as the quality assurance system of the nationwide healthcare insurance data for inpatient hospital treatment (QSR) by the German local healthcare fund (AOK). Therefore, the quality of care of all certified centres for joint replacement (EPZ) after primary hip and knee arthroplasty was to be examined for the first time. These data were subsequently compared to the data of the EPRD. MATERIALS AND METHODS: In EPZ that provided care to at least one AOK-insured patient in 2016, the risk-adjusted 3­year revision rate and the SMR-value (standardised mortality or morbidity ratio), which is the quotient of the observed and expected revision rate, were analysed as markers for the quality of care. Annual hospital volume, type of centre and audit results were examined as possible influencing factors. RESULTS: In the group comparison, significant differences (p = 0.042) for the SMR value of the 3­year revision rate were demonstrated for hip arthroplasty with regard to the EPZ type. The annual number of primary hip arthroplasties, however, did not influence the 3­year revision rate. For knee arthroplasties, no effect of the defined categories on the 3­year revision rate and its SMR value was observed. The comparison of our 3­year revision rates with those of the EPRD showed similar results for the hip but indicated significant differences for the knee. CONCLUSION: We did not observe a correlation between quality of care and annual hospital volume in certified EPZ. However, different quality assurance procedures can lead to different results with respect to the outcome quality. Therefore, a considerably improved interaction of the German quality systems must be achieved. Participation in the EPRD is not sufficient for this. Rather, a complete report of all arthroplasties must be required, at least with the achievement of a minimum reporting rate per participating hospital. Uniform inclusion and exclusion criteria should be defined.

Intraarticular injection of platelet-rich plasma reduces inflammation in a pig model of rheumatoid arthritis of the knee joint.

OBJECTIVE: Treatment options for rheumatoid arthritis range from symptomatic approaches to modern molecular interventions such as inhibition of inflammatory mediators. Inhibition of inflammation by platelet-rich plasma (PRP) has been proposed as a treatment for tendinitis and osteoarthritis. The present study was undertaken to investigate the effect of PRP on antigen-induced arthritis (AIA) of the knee joint in a large animal model. METHODS: Six-month-old pigs (n = 10) were systemically immunized by bovine serum albumin (BSA) injection, and arthritis was induced by intraarticular BSA injection. PRP was injected into the knee joints of 5 of the animals after 2 weeks. An additional 5 animals received no systemic immunization (controls). Signs of arthritis were documented by plain histologic analysis, Safranin O staining, and immunohistochemistry analysis for type II collagen (CII), interleukin-6 (IL-6), and vascular endothelial growth factor (VEGF). Interleukin-1ß (IL-1ß), IL-6, tumor necrosis factor α (TNFα), VEGF, and insulin-like growth factor 1 (IGF-1) protein content was measured by Luminex assay. RESULTS: In the pigs with AIA, plain histologic analysis revealed severe arthritic changes in the synovium. Safranin O and CII staining showed decreased proteoglycan and CII content in cartilage. Immunohistochemistry analysis revealed increased levels of IL-6 and VEGF in synovium and cartilage, and protein concentrations of IL-6, VEGF, IL-1ß, and IGF-1 in synovium and cartilage were elevated as well; in addition, TNFα protein was increased in cartilage. Treatment with PRP led to attenuation of these arthritic changes in the synovium and cartilage. CONCLUSION: We have described a porcine model of AIA. Experiments using this model demonstrated that PRP can attenuate arthritic changes as assessed histologically and based on protein synthesis of typical inflammatory mediators in the synovial membrane and cartilage.

Evaluation of the patient-accompanying app "alley ortho companion" for patients with osteoarthritis of the knee and hip: study protocol for a randomized controlled multi-center trial.

BACKGROUND: Osteoarthritis (OA) is one of the most common disabilities in the elderly. When conservative management fails, total joint arthroplasty (TJA) is the treatment of choice for end-stage OA. Since quality and durability of implants has steadily improved, pre -and postsurgical processes moved into the focus of research. Hence, eHealth approaches offer an opportunity to provide a more available continuity of care. Regarding individualized pre-, peri-, and postsurgical stages, eHealth is expected to improve patient engagement, self-care, and outcomes across the surgical pathway. Aim of this study is to evaluate the effectiveness of the eHealth application "alley" as an adjuvant intervention to TJA. The app provides comprehensive information to empower patient with hip or knee OA to prepare and accompany them for their TJA surgery. Our primary hypothesis is that the pre- and postoperative adjuvant use of the eHealth application "alley" (intervention group, IG) leads to improved functional outcome. METHODS: Prospective, randomized, controlled, multi-center trial including n = 200 patients diagnosed with hip and n = 200 patients with knee OA (n = 200) scheduled for TJA. Patients of both groups will be randomly assigned to one of two study arms. Patients in the intervention group will receive access to the functions of the "alley" app. The app presents informative (e.g., information about osteoarthritis), organizational (e.g., information about medical rehabilitation), and emotional/empowerment (e.g., information about the relationship between mood and pain) content. Patients evaluate their condition and functional level by means of standardized digitally questionnaires. Patients in the control group will not receive any functions of the app. Assessments will be performed at baseline before, 10 days after, 1 months after, 3 months after, 6 months after, and 12 months after TJA. Primary outcome is change from baseline measured by the Hip Osteoarthritis Outcome Score or Knee injury and Osteoarthritis Outcome Score 3 months after TJA. The statistical analysis (t-test for independent variables with effect size Cohen's d) is performed separately for patients with TKA and THA. DISCUSSION: Overall, the study aims to improve the understanding of the benefits of eHealth applications in the treatment of elderly patients with knee or hip arthroplasty. The approach is novel since a health care companion is combined with a digital information platform enabling direct and continuous feedback from the patients to the therapeutic treatment team. As the study investigate the effectiveness under everyday conditions, it is not feasible to control whether the patients in the IG read the educational information of the app respectively the control group consume additional information from other sources. However, this increases the external validity of the study if significant effects for the app can be demonstrated. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00025608. Registered on 21 June 2021.

Minimal-invasive posterior approach for total hip arthroplasty versus standard lateral approach.

In this prospective study we compared clinical and radiological results and rehabilitation progress of 64 patients who underwent total hip arthroplasty using the standard lateral approach with 64 patients operated with a minimal-invasive (MIS) posterior approach. The outcome of our study did not show any significant differences with regard to patient's safety such as complication rate and radiological assessment of the cup position. There was no difference in the duration of surgery, blood loss, hospital stay and postoperative leg length discrepancy. Rehabilitation milestones were achieved earlier by MIS patients and three and six months postoperatively, the Harris Hip Score of the MIS group was significantly higher.

Endoscopic treatment of calcinosis circumscripta of the hip joint: a report of 2 cases of arthroscopic removal of a calcific deposition between the labrum and capsule.

We present 2 cases of arthroscopic removal of a calcific deposition in the form of calcinosis circumscripta between the labrum and capsule of the hip joint. Case 1 was a 42-year-old woman who presented with complaints of a 2-year history of right hip pain. Radiographs showed a calcific deposition in the area of the acetabular roof. Arthroscopy showed a calcific deposition between the labrum and capsule in the form of calcinosis circumscripta. At the 4-month follow up, she was symptom free with painless full range of motion. Case 2 was a 48-year-old slim woman who presented with complaints of right hip pain over the last 6 months. Preoperative radiographs showed a hip with a calcific deposition lateral to the pronounced acetabular roof. At the 4-month follow up after removal, she was also symptom free. To our knowledge, these are the first patients with calcinosis circumscripta treated by hip arthroscopy. We recommend the endoscopic approach, which is effective and minimally invasive, for treatment of calcinosis circumscripta and other calcifications in the hip joint. Especially in young patients, with a high activity level and without any symptoms of hip osteoarthritis, hip arthroscopy is the ideal treatment.

Influence of Revision Surgeries and Revision Rate on Quality Indicators in Certified Centres for Joint Replacement (EndoProthetikZentren). / Einfluss der Wechseleingriffe und der Wechselrate auf die Qualitätsindikatoren in zertifizierten EndoProthetikZentren.

BACKGROUND: The annual report of EndoCert publishes the results of the quality indicators (QI) and key figures of all certified centres for joint replacement (EndoProthetikZentren - EPZ). For some results it seems that centres with fewer revisions might have higher complication rates. However, to avoid misinterpretation the results have to be evaluated in more detail. The influence of the quantity of the revisions or the revision quotient on the quality of outcome was investigated. MATERIAL AND METHODS: This study included all certified EPZ and centres of excellence for joint replacement (EPXmax) (n = 492) and evaluated the data from 2016. Centres beyond the action limit were identified with the help of funnel plots and a confidence limit of 99.7% as action limit. Additionally data of the quality indicators were analysed with ANCOVA. The level of significance was p < 0.05. RESULTS: The comparison by ANCOVA with number of revisions as co-variate showed no differences in the complication rates when related to the quantity of revisions. When considering a so called revision quotient (ratio of revision to all joint replacements) significant differences in the rate of fractures and fissures as well as in mortality for hip replacements and also in mortality for knee replacements were observed. CONCLUSION: EPZ with fewer revisions do not have higher complication rates than centers with high numbers of revisions. Thus, the quantity of revisions has no influence on the quality of the outcome, considering that on the basis of the data of the EndoCert system no risk adjustment of patient-specific data was performed. Therefore the revisioin quotient of an EPZ shows that quantity is not equal with quality.

[Pre-operative Evaluation of Patients Undergoing Total Joint Arthroplasty - What is Essential?] / Was ist ein Muss in der präoperativen Diagnostik vor elektiver Endoprothetik?

Background A thorough pre-operative evaluation is required prior to total joint arthroplasty (TJA). The objective of screening is to identify patient- and procedure-related risk constellations. Pre-operative diagnostic measures are vital in order to anticipate, reduce or even eliminate threats to patient safety. Furthermore, the clinical and radiographical workup may confirm the indication and type of surgical procedure, but this is not the subject of this article. Objective An overview of the current literature on pre-operative diagnostic principles is presented. Methods A selective literature analysis was performed. Results We identified recommendations related to the following: (1) preoperative anaemia, (2) metabolic optimisation, (3) weight control, (4) obstructive sleep apnoea, (5) MRSA and skin decontamination, (6) urinary tract infections (UTI), (7) dental screening (8) cardiological workup, (9) technical considerations on primary and revision arthroplasty. Conclusion While clear evidence-based recommendations for every item are not yet available, a critical pre-operative evaluation including history taking, physical exam, laboratory tests and imaging studies remains essential. The ongoing evolution of improved perioperative care and implications for patient safety will further increase the scope of necessary preoperative diagnostic measures.

Arthroscopic versus conservative treatment of osteochondritis dissecans of the knee: value of magnetic resonance imaging in therapy planning and follow-up.

PURPOSE: Magnetic resonance imaging (MRI) was used to control the short-term outcome of osteochondritis dissecans (OCD) of the femoral condyle depending on conservative or surgical treatment at the beginning of therapy. TYPE OF STUDY: Case series. METHODS: Treatment planning for OCD depended on the stage on MRI when analyzing the appearance of the interface between parent bone and fragment on T1- and T2-weighted images. Twenty-seven patients received conservative treatment and 46 patients underwent arthroscopic surgery. After 20 to 24 months, patients were re-evaluated by MRI to assess the condition of bony fragment, parent bone, and interface so as to determine partial or complete remission, no change, or progression of OCD. RESULTS: After conservative treatment, MRI showed partial or complete remission in 30% of patients and no change in 63%. Arthroscopic treatment led to remission in 37% and to no change in 57%. Progressive disintegration of OCD was found on MRI in 7% of conservatively treated patients and in 7% of the surgery patients. In 33.3% of the patients initially treated conservatively, it was decided to treat them arthroscopically because of ongoing, unacceptable clinical symptoms. CONCLUSIONS: The rates of remission and progression were not significantly different between the groups. The patients' age was significantly correlated to the rate of consolidation. OCD in juveniles under 16 years of age followed a milder course than in adults.