Nikolai Ramadanov

Dr. Nikolai Ramadanov

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Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 May 2024 in Medicina
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JLJonathan Lettner
Jonathan Lettner
Aleksandra KrólikowskaAleksandra Królikowska
Aleksandra Królikowska
NRNikolai Ramadanov
Nikolai Ramadanov
Łukasz OleksyŁukasz Oleksy
Łukasz Oleksy
HHHassan Tarek Hakam
Hassan Tarek Hakam
Robert PrillRobert Prill
Robert Prill
Background and Objectives: Muscle properties are critical for performance and injury risk, with changes occurring due to physical exertion, aging, and neurological conditions. The MyotonPro device offers a non-invasive method to comprehensively assess muscle biomechanical properties. This systematic review evaluates the reliability of MyotonPro across various muscles for diagnostic purposes. Materials and Methods: Following PRISMA guidelines, a comprehensive literature search was conducted in Medline (PubMed), Ovid (Med), Epistemonikos, Embase, Cochrane Library, Clinical trials.gov, and the WHO International Clinical Trials platform. Studies assessing the reliability of MyotonPro across different muscles were included. A methodological quality assessment was performed using established tools, and reviewers independently conducted data extraction. Statistical analysis involved summarizing intra-rater and inter-rater reliability measures across muscles. Results: A total of 48 studies assessing 31 muscles were included in the systematic review. The intra-rater and inter-rater reliability were consistently high for parameters such as frequency and stiffness in muscles of the lower and upper extremities, as well as other muscle groups. Despite methodological heterogeneity and limited data on specific parameters, MyotonPro demonstrated promising reliability for diagnostic purposes across diverse patient populations. Conclusions: The findings suggest the potential of MyotonPro in clinical assessments for accurate diagnosis, treatment planning, and monitoring of muscle properties. Further research is needed to address limitations and enhance the applicability of MyotonPro in clinical practice. Reliable muscle assessments are crucial for optimizing treatment outcomes and improving patient care in various healthcare settings.

26 August 2023 in Journal of Orthopaedic Surgery and Research
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Journal Article
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NRNikolai Ramadanov
Nikolai Ramadanov
KJKatarzyna Jóźwiak
Katarzyna Jóźwiak
MHMichael Hauptmann
Michael Hauptmann
PLPhilip Lazaru
Philip Lazaru
PMPolina Marinova-Kichikova
Polina Marinova-Kichikova
RBRoland Becker
Roland Becker
Background: Our aim was to determine the best operative procedure in human participants with a displaced or non-displaced femoral neck fracture comparing cannulated screw (CS) fixation, dynamic hip screw (DHS) fixation, hemiarthroplasty (HA), and total hip arthroplasty (THA) in terms of surgical and functional outcomes, reoperation and postoperative complications. Methods: We searched PubMed, The Cochrane Library, Clinical trials, CINAHL, and Embase for randomized controlled trials (RCTs) or quasi-RCTs up to 31 July 2022. A frequentist network meta-analysis was performed to assess the comparative effects of the four operative procedures, using fixed-effects and random-effects models. Mean differences (MDs) with 95% confidence intervals (CIs) were estimated for continuous variables and odds ratios (ORs) with 95% CIs were estimated for binary variables. Results: A total of 33 RCTs with 5703 patients were included in our network meta-analysis. CS fixation was best in terms of operation time (CS: MD = − 57.70, 95% CI − 72.78; − 42.62; DHS: MD = − 53.56, 95% CI − 76.17; − 30.95; HA: MD = − 20.90, 95% CI − 30.65; − 11.15; THA: MD = 1.00 reference) and intraoperative blood loss (CS: MD = − 3.67, 95% CI − 4.44; − 2.90; DHS: MD = − 3.20, 95% CI − 4.97; − 1.43; HA: MD = − 1.20, 95% CI − 1.73; − 0.67; THA: MD = 1.00 reference). In life quality and functional outcome, measured at different time points with EQ-5D and the Harris Hip Score (HHS), THA ranked first and HA second (e.g. EQ-5D 2 years postoperatively: CS: MD = − 0.20, 95% CI − 0.29; − 0.11; HA: MD = − 0.09, 95% CI − 0.17; − 0.02; THA: MD = 1.00 reference; HHS 2 years postoperatively: CS: MD = − 5.50, 95% CI − 9.98; − 1.03; DHS: MD = − 8.93, 95% CI − 15.08; − 2.78; HA: MD = − 3.65, 95% CI − 6.74; − 0.57; THA: MD = 1.00 reference). CS fixation had the highest reoperation risk, followed by DHS fixation, HA, and THA (CS: OR = 9.98, 95% CI 4.60; 21.63; DHS: OR = 5.07, 95% CI 2.15; 11.96; HA: OR = 1.60, 95% CI 0.89; 2.89; THA: OR = 1.00 reference). Conclusion: In our cohort of patients with displaced and non-displaced femoral neck fractures, HHS, EQ-5D, and reoperation risk showed an advantage of THA and HA compared with CS and DHS fixation. Based on these findings, we recommend that hip arthroplasty should be preferred and internal fixation of femoral neck fractures should only be considered in individual cases. Level of evidence I: a systematic review of randomized controlled trials. Trial registration: PROSPERO on 10 August 2022 (CRD42022350293).

27 May 2025 in Orthopaedic Surgery
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Journal Article
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NRNikolai Ramadanov
Nikolai Ramadanov
MVMaximilian Voss
Maximilian Voss
RDRadharani Michelle Diallo
Radharani Michelle Diallo
JLJonathan Lettner
Jonathan Lettner
HHHassan Tarek Hakam
Hassan Tarek Hakam
RHRobert Hable
Robert Hable
Background: Total hip arthroplasty (THA) is a highly successful orthopedic procedure, with numerous meta‐analyses published to optimize its outcomes. However, the reliability of their results and conclusions depends heavily on the use of appropriate statistical methods. Therefore, the aim was to test the reliability of statistical methods in meta‐analyses of THA by examining the degree of heterogeneity, the effect of different between‐study variance estimators, and the equality of sample size of pooled primary studies.Methods: The literature was systematically searched in PubMed from January 1, 2022, to December 31, 2023, for meta‐analyses on THA. The quality of the meta‐analyses was assessed using the revised Measurement Tool to Assess Systematic Reviews (AMSTAR 2). All meta‐analyses were recalculated using eight different heterogeneity estimators. The following indicators were considered: inequality of patient numbers, proportion of random‐effects and fixed‐effects models, heterogeneity with I 2 value, ratio of effect sizes (RES), ratio of confidence interval width (RCIW), and the number of significant results. Mixed linear regression was then used to analyze whether the effect sizes and CIW were significantly different using different heterogeneity estimators. Finally, all examined meta‐analyses were recalculated using the eight heterogeneity estimators and the Hartung–Knapp (HK) adjustment.Results: Of the 24 meta‐analyses examined, 15 reported an outcome using a mean difference and 20 reported an outcome using an odds ratio. The quality assessment identified 10 meta‐analyses of high quality, 7 of moderate quality, 4 of low quality, and 3 of critically low quality. The significance of the examined meta‐analyses varied considerably depending on the heterogeneity estimators used. In particular, the DerSimonian and Laird and Hunter–Schmidt heterogeneity estimators tended to produce false‐positive results. The meta‐analyses examined generally did not use HK adjustment. This effect is amplified when combined with the weak DerSimonian and Laird heterogeneity estimator, which were used in almost all examined meta‐analyses.Conclusion: Without HK adjustment, the results depend strongly on the heterogeneity estimator chosen and there is a risk of false positives, especially for the widely used DerSimonian and Laird heterogeneity estimator. For HK adjustment, the choice of heterogeneity estimator seems to play a less important role. We recommend the use of more reliable heterogeneity estimators as well as the HK adjustment as a measure to improve the statistical methodology of meta‐analyses. This study highlights the critical need for improved statistical rigor in meta‐analyses of THA, ensuring more reliable evidence for clinical decision‐making and guideline development.

20 January 2020 in Scientific Reports
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NRNikolai Ramadanov
Nikolai Ramadanov
ITIonel Toma
Ionel Toma
HHHarald Herkner
Harald Herkner
RKRoman Klein
Roman Klein
WBWilhelm Behringer
Wilhelm Behringer
GMGerrit Matthes
Gerrit Matthes
To investigate the influence of various factors on the two outcome parameters “procedure - specific complication” (femoral head necrosis, infection, nonunion, femoral neck shortening, screw loosening, implant penetration) and “functional outcome” in patients with displaced and undisplaced femoral neck fracture treated by cannulated screw fixation. All cases of a femoral neck fracture, operated by cannulated screw fixation, in the period from December 2014 to December 2017 were included. The observation period of the included patients was 12 months. Information on their outcome was collected after evaluation of current x-ray images and on request from the responsible further treatment physician. Continuous data were presented as mean value ± standard deviation, categorical data as absolute and relative frequency. The effect of potential factors on endpoints was estimated with a multivariable logistic regression analysis and 95% confidence intervals calculated. The null hypothesis Odds Ratio = 1 was checked by the Wald test. The likelihood ratio test was used to test for deviation from linearity. The mean age of the 56 included patients was 72 years (36 min, 96 max), 44.5% (n = 25) were male and 55.5% (n = 25) female. The femoral neck fractures were classified as follows: Garden I: 73%, Garden II: 16%, Garden III: 11%, Pauwels I: 73%, Pauwels II: 21%, Pauwels III: 5%, 31-B1: 73%, 31-B2: 27%, 31-B3: 0%. The factor patient age showed a statistically significant influence on the outcome parameter procedure-specific complication. None of the remaining factors examined showed a statistically significant influence on both outcome parameters procedure-specific complication and functional outcome. 69% of the patients from age 80 onwards suffered a procedure-specific complication. A rate of 41% procedure-specific complications as an outcome parameter in trauma surgery shows a necessity for improvement. The increasing risk of procedure-specific complications for patients with a femoral neck fracture treated by cannulated screw fixation is associated with rising patient age. A more stable head-perserving operative method or an endoprosthetic procedure should be considered in high-risk patients (≥80 y.o.).

24 August 2021 in PLOS ONE
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PLPhilip Lazaru
Philip Lazaru
SBSimon Bueschges
Simon Bueschges
NRNikolai Ramadanov
Nikolai Ramadanov
Objectives: Several systematic reviews and meta-analyses on short-term outcomes between total hip arthroplasty (THA) through direct anterior approach (DAA) compared to THA through conventional (including anterior, anterolateral, lateral transgluteal, lateral transtrochanteric, posterior, and posterolateral) approaches (CAs) in treatment of hip diseases and fractures showed contradicting conclusions. Our aim was to draw definitive conclusions by conducting both a fixed and random model meta-analysis of quality randomized controlled trials (RCTs) and by comparison with related meta-analyses.Design: We performed a systematic literature search up to May 2020 to identify RCTs, comparing THA through DAA with THA through CAs and related meta-analyses. We conducted risk of bias and level of evidence assessment in accordance with the Cochrane’s Risk of Bias 2 tool and with the guidelines of the Centre for Evidence-Based Medicine. We estimated mean differences (MD) with 95% confidence intervals (CI) through fixed and random effects models, using the DerSimonian and Laird method. Heterogeneity was assessed using tau-square (τ2). Our conclusions take into account the overall results from related meta-analyses.Results: Nine studies on THA through DAA met the criteria for final meta-analysis, involving 998 patients. Three studies were blinded RCTs with a level I evidence, the other 6 studies were non-blinded RCTs with a level II evidence. We came to the following results for THA through DAA compared to THA through CAs: operation time (I2= 92%, p<0.01; fixed: MD = 15.1, 95% CI 13.1 to 17.1; random: MD = 18.1, 95% CI 8.6 to 27.5); incision length (I2= 100%, p<0.01; fixed: MD = -2.9, 95% CI -3.0 to -2.8; MD = -1.1, 95% CI -4.3 to 2.0); intraoperative blood loss (I2= 87%, p<0.01; fixed: MD = 51.5, 95% CI 34.1 to 68.8; random: MD = 51.9, 95% CI -89.8 to 193.5); VAS 1 day postoperatively (I2= 79%, p = 0.03; fixed: MD = -0.8, 95% CI -1.2 to -0.4; random: MD = -0.9, 95% CI -2.0 to 0.15); HHS 3 months postoperatively (I2= 52%, p = 0.08; fixed: MD = 2.8, 95% CI 1.1 to 4.6; random: MD = 3.0, 95% CI -0.5 to 6.5); HHS 6 months postoperatively (I2= 0%, p = 0.67; fixed: MD = 0.9, 95% CI -1.1 to 2.9; random: MD = 0.9, 95% CI -1.1 to 2.9); HHS 12 months postoperatively (I2= 0%, p = 0.79; fixed: MD = 0.7, 95% CI -0.9 to 2.4; random: MD = 0.7, 95% CI -0.9 to 2.4). We compared our findings with 7 related meta-analyses.Conclusions: Considering the results of our meta-analysis and the review of related meta-analyses, we can conclude that short-term outcomes of THA through DAA were overall better than THA through CAs. THA through DAA had a shorter incision length, a tendency towards a lower pain VAS 1 day postoperatively and better early postoperative functional outcome than THA through CAs. The intraoperative blood loss showed indifferent results. THA through DAA had a longer operation time than THA through CAs.

16 February 2024 in JMIR Formative Research
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Journal Article
Open access
HHHassan Tarek Hakam
Hassan Tarek Hakam
Robert PrillRobert Prill
Robert Prill
LKLisa Korte
Lisa Korte
BLBruno Lovreković
Bruno Lovreković
MOMarko Ostojic
Marko Ostojic
FMFelix Muehlensiepen
Felix Muehlensiepen
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.