Ümit Mert

Dr. Ümit Mert

orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

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

Representative Publications

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Verified
Journal Article
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ÜMÜmit Mert
Ümit Mert
MKMoh’d Yazan Khasawneh
Moh’d Yazan Khasawneh
MGMaher A. Ghandour
Maher A. Ghandour
AZAhmad Al Zuabi
Ahmad Al Zuabi
KHKlemens Horst
Klemens Horst
KKKoroush Kabir
Koroush Kabir
Background/Objectives: Total knee arthroplasty (TKA) is a common procedure for knee osteoarthritis. While conventional TKA (C-TKA) remains standard, robot-assisted TKA (RA-TKA) has been introduced to enhance implant positioning and clinical outcomes. However, its comparative benefits remain unclear. This systematic review and meta-analysis compared RA-TKA with C-TKA, examining the influence of robotic system, surgeon experience, and follow-up duration. Methods: A systematic search was conducted across the PubMed, Scopus, Web of Science, and Cochrane Library databases. Randomized controlled trials (RCTs) comparing RA-TKA with C-TKA were included. Outcomes were categorized into clinical, radiographic, and safety endpoints. Subgroup and meta-regression analyses explored factors influencing outcome variability, including robotic system, number of surgeons, and follow-up duration. Results: Twenty-five RCTs (5614 patients) were analyzed. RA-TKA showed modest improvements in clinical outcomes, such as KSS and VAS pain scores, but results varied across subgroups. RA-TKA demonstrated a significantly better flexion range of motion (ROM) in certain countries (e.g., Russia, MD = 10; 95%CI: 5.44, 14.56) and with specific robotic systems (e.g., NAVIO). No significant differences were found in OKS and HSS scores. Radiographic outcomes, including the HKA Angle, varied by robotic system, with NAVIO and YUANHUA showing better alignment than C-TKA. Complication rates were comparable, though RA-TKA had a higher risk of conversion to open surgery (10% vs. 2%). Meta-regression identified robotic system and surgeon experience as key predictors of outcome variability. Conclusions: RA-TKA offers advantages in implant alignment and postoperative pain reduction. However, benefits are inconsistent across settings, and some robotic systems may not provide improvements over C-TKA.

18 August 2022 in Frontiers in Immunology
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Journal Article
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LLLudmila Lupu
Ludmila Lupu
KHKlemens Horst
Klemens Horst
JGJohannes Greven
Johannes Greven
ÜMÜmit Mert
Ümit Mert
JLJudith A.K. Ludviksen
Judith A.K. Ludviksen
TMTom Mollnes
Tom Mollnes
Dysfunctional complement activation and Toll-like receptor signaling immediately after trauma are associated with development of trauma-induced coagulopathy and multiple organ dysfunction syndrome. We assessed the efficacy of the combined inhibition therapy of complement factor C5 and the TLR co-receptor CD14 on thrombo-inflammation and organ damage in an exploratory 72-h polytrauma porcine model, conducted under standard surgical and intensive care management procedures. Twelve male pigs were subjected to polytrauma, followed by resuscitation (ATLS® guidelines) and operation of the femur fracture (intramedullary nailing technique). The pigs were allocated to combined C5 and CD14 inhibition therapy group (n=4) and control group (n=8). The therapy group received intravenously C5 inhibitor (RA101295) and anti-CD14 antibody (rMil2) 30 min post-trauma. Controls received saline. Combined C5 and CD14 inhibition reduced the blood levels of the terminal complement complex (TCC) by 70% (p=0.004), CRP by 28% (p=0.004), and IL-6 by 52% (p=0.048). The inhibition therapy prevented the platelet consumption by 18% and TAT formation by 77% (p=0.008). Moreover, the norepinephrine requirements in the treated group were reduced by 88%. The inhibition therapy limited the organ damage, thereby reducing the blood lipase values by 50% (p=0.028), LDH by 30% (p=0.004), AST by 33%, and NGAL by 30%. Immunofluorescent analysis of the lung tissue revealed C5b-9 deposition on blood vessels in five from the untreated, and in none of the treated animals. In kidney and liver, the C5b-9 deposition was similarly detected mainly the untreated as compared to the treated animals. Combined C5 and CD14 inhibition limited the inflammatory response, the organ damage, and reduced the catecholamine requirements after experimental polytrauma and might be a promising therapeutic approach.

3 May 2024 in Bone & Joint Research
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RGRald Victor Maria Groven
Rald Victor Maria Groven
CKChristel Kuik
Christel Kuik
JGJohannes Greven
Johannes Greven
ÜMÜmit Mert
Ümit Mert
FBFreek G. Bouwman
Freek G. Bouwman
Martijn van GriensvenMartijn van Griensven
Martijn van Griensven
Aims The aim of this study was to determine the fracture haematoma (fxH) proteome after multiple trauma using label -free proteomics, comparing two different fracture treatment strategies. Methods A porcine multiple trauma model was used in which two fracture treatment strategies were compared: early total care (ETC) and damage control orthopaedics (DCO). fxH was harvested and analyzed using liquid chromatography -tandem mass spectrometry. Per group, discriminating proteins were identified and protein interaction analyses were performed to further elucidate key biomolecular pathways in the early fracture healing phase. Results The early fxH proteome was characterized by immunomodulatory and osteogenic proteins, and proteins involved in the coagulation cascade. Treatment -specific proteome alterations were observed. The fxH proteome of the ETC group showed increased expression of pro -inflammatory proteins related to, among others, activation of the complement system, neutrophil functioning, and macrophage activation, while showing decreased expression of proteins related to osteogenesis and tissue remodelling. Conversely, the fxH proteome of the DCO group contained various upregulated or exclusively detected proteins related to tissue regeneration and remodelling, and proteins related to anti-inflammatory and osteogenic processes. Conclusion The early fxH proteome of the ETC group was characterized by the expression of immunomodulatory, mainly pro -inflammatory, proteins, whereas the early fxH proteome of the DCO group was more regenerative and osteogenic in nature. These findings match clinical observations, in which enhanced surgical trauma after multiple trauma causes dysbalanced inflammation, potentially leading to reduced tissue regeneration, and gained insights into regulatory mechanisms of fracture healing after severe trauma.

21 March 2012 in European Surgical Research
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Journal Article
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ÜMÜmit Mert
Ümit Mert
RGRald Victor Maria Groven
Rald Victor Maria Groven
JGJohannes Greven
Johannes Greven
ZHZhizhen He
Zhizhen He
MMMohamad Agha Mahmoud
Mohamad Agha Mahmoud
FHFrank Hildebrand
Frank Hildebrand
Introduction: Coagulopathic disorders (CDs) complicate treatment in polytraumatised patients. Against this background, operative strategies for fracture management are controversial in this cohort. This study therefore investigated the effects of two established operative concepts, early total care (ETC) and damage control orthopaedics (DCO), on CD in a large-animal polytrauma (PT) model. Methods: Twenty-two animals (Sus scrofa domesticus) sustained PT involving blunt-chest trauma, liver laceration, bilateral femur fracture, and pressure-controlled haemorrhagic shock. After resuscitation, animals were allocated to ETC (n = 8), DCO (n = 8), or served as a non-traumatised control group (CG, n = 6). Animals were ventilated and monitored under ICU standards for 72 h. Blood samples were collected at baseline and post-trauma after 1.5, 2.5, 24, 48, and 72 h. Plasminogen activator inhibitor-1 (PAI-1) and thrombin-antithrombin (TAT) complex concentrations were determined by ELISA. Results: Compared to the CG, ETC and DCO subjects had significantly increased plasma concentrations of PAI-1 after 2.5 h (CG vs. ETC: p = 0.0050, CG vs. DCO: p = 0.0016). Furthermore, the ETC group showed significantly increased plasma PAI-1 concentrations after 24 h compared to the CG and DCO groups (CG vs. ETC: p = 0.0002, DCO vs. ETC: p = 0.0004). During the later clinical course, concentrations of TAT were significantly increased in the ETC group compared to the CG and DCO group after 72 h (CG vs. ETC: p = 0.0290, DCO vs. ETC: p = 0.0322). Conclusion: PT is strongly associated with CD in the early post-traumatic course. In comparison to DCO, ETC appeared to be negatively associated with CD. Future studies must investigate this impact, especially in those patients admitted with trauma-induced coagulopathy, to improve outcomes.

27 August 2024 in Journal of Clinical Medicine
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Journal Article
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ÜMÜmit Mert
Ümit Mert
MMMohamad Agha Mahmoud
Mohamad Agha Mahmoud
MGMaher A. Ghandour
Maher A. Ghandour
AZAhmad Al Zuabi
Ahmad Al Zuabi
MSMarco Speicher
Marco Speicher
KKKoroush Kabir
Koroush Kabir
Background: Femoral neck fractures pose significant surgical challenges with high morbidity and mortality. Traditional freehand screw placement often yields variable outcomes. Recent robotic advancements offer a promising alternative with enhanced precision. Methods: This systematic review compares the efficacy and safety of robot-assisted versus freehand techniques. A comprehensive literature search across multiple databases up to July 2024 included studies comparing both techniques. Primary outcomes were the union rate and time, functional outcomes, operative time, intraoperative parameters, and complication rates. Meta-regression analyses identified treatment response determinants. Results: Twenty-four studies (1437 patients) were included. Robot-assisted screw placement significantly improved the union rate, reduced the union time, and showed superior functional outcomes. Additionally, it resulted in shorter operative times, less intraoperative blood loss, and fewer instances of fluoroscopy and guide pin insertion. The risk of femoral neck necrosis was notably lower with robotic assistance. Meta-regression highlighted the robot type, patient age, and sample size as significant factors. Conclusions: Despite the promise of robot-assisted screw placement, limitations exist. The evidence being mainly from China raises concerns about generalizability. The lack of long-term follow-up data hinders assessment of technique durability. Unreported surgeon expertise levels and learning curves affect result validity. High initial costs and steep learning curves of robotic systems also present barriers to widespread adoption.

1 February 2025 in The Bone & Joint Journal
Verified
Journal Article
Closed access
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RGRald Victor Maria Groven
Rald Victor Maria Groven
ÜMÜmit Mert
Ümit Mert
JGJohannes Greven
Johannes Greven
KHKlemens Horst
Klemens Horst
VJVirginie Joris
Virginie Joris
Martijn van GriensvenMartijn van Griensven
Martijn van Griensven
Aims: The aims of this study, using a porcine model of multiple trauma, were to investigate the expression of microRNAs at the fracture site, in the fracture haematoma (fxH) and in the fractured bone, compared with a remote unfractured long bone, to characterize the patterns of expression of circulating microRNAs in plasma, and identify and validate messenger RNA (mRNA) targets of the microRNAs.Methods: Two multiple trauma treatment strategies were compared: early total care (ETC) and damage control orthopaedics (DCO). For this study, fxH, fractured bone, unfractured control bone, plasma, lung, and liver samples were harvested. MicroRNAs were analyzed using quantitative real-time polymerase chain reaction arrays, and the identified mRNA targets were validated in vivo in the bone, fxH, lung, and liver tissue.Results: MicroRNA expression was associated with the trauma treatment strategy and differed depending on the type of sample. In the ETC group, a more advanced fracture healing response, as reflected by the expression of osteogenic microRNAs, was seen compared with the DCO group. DCO treatment resulted in a more balanced immune response in the systemic circulation as represented by significant upregulations of several anti-inflammatory microRNAs. The in vivo validation of the abundance of putative mRNA targets reflected the levels of microRNAs which were identified.Conclusion: Local and systemic microRNA patterns of expression were identified, specific for the treatment strategy in multiple trauma, which corresponded with the expression of mRNA at the fracture site and in target organs. These findings match clinical observations and offer insights into the cellular communication which may underlie the effects of using different surgical strategies in patients with multiple trauma, both locally and systemically. We also identified a systemic involvement of microRNAs in multiple trauma which may include distant cellular communication between injured tissues. Further research may further describe the temporospatial role of circulating microRNAs after multiple trauma, their potential role in communication between organs, and prospective therapeutic applications.Cite this article: Bone Joint J 2025;107-B(2):193–203.