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[FG] Müller Andreas Marc

Projects & Collaborations

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InnoTreat: Towards Personalized Treatment Decisions with Digital Twins

Research Project  | 4 Project Members

Das Projekt InnoTreat: Towards Personalized Treatment Decisions with Digital Twins zielt darauf ab, die klinische Diagnose und Behandlungsentscheidungen bei Schulterpathologien zu präzisieren. Durch die Integration von patientenspezifischer Anatomie in biomechanische Simulationen soll das Projekt Einblick in die zugrunde liegenden Mechanismen der Schulterpathologie geben und dadurch Rehabilitationsprogramme zielgerichteter abstimmen. Das Projekt konzentriert sich auf Rupturen der Rotatorenmanschette, von denen ein erheblicher Teil der Bevölkerung betroffen ist, und befasst sich mit den Grenzen der derzeitigen Behandlungsmöglichkeiten durch die Entwicklung einer digitalen Zwillingsanwendung, die patientenspezifische Diagnosen und veränderte Biomechanik visualisiert. Die institutionenübergreifende Zusammenarbeit nutzt die Expertise in der Bildgebung (Universität Zürich), der Biomechanik (ZHAW) und der klinischen Praxis (Universitätsspital Basel) im Rahmen einer iterativen Forschungszusammenarbeit.

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Surgical safety and effectiveness in orthopedics: Swiss-wide multicenter evaluation and prediction of core outcomes in arthroscopic rotator cuff reconstruction

Research Project  | 2 Project Members

Valid clinical outcome data are essential to assess the safety and effectiveness of surgical interventions, to perform benchmarking activities and to foster a well-founded decision-making process in orthopedics. In the fields of arthroscopic rotator cuff repair (ARCR), the number of ARCR procedures and published studies has grown exponentially in the last decade, yet reporting standards differ dramatically. This is particularly notable concerning adverse events (AE) as in most fields of orthopedic surgery. In addition, published prognostic studies were methodologically poor, based on small datasets and explored only limited numbers of potentially influencing factors.A prospective multicenter clinical study of a large ARCR patient cohort will be implemented on a representative group of 17 Swiss and one German specialized clinics allowing for the evaluation of targeted core safety, clinical and patient-reported outcomes. The primary objective will be the development of prediction models for individual patients. The primary outcomes will be the patient-reported subjective assessment of shoulder function (Oxford Shoulder Score) and the occurrence of shoulder stiffness up to 12 months after primary repair surgery. Multiple prognostic factors will be investigated including patient baseline demographics, psychological, socioeconomic and clinical factors, rotator cuff integrity and concomitant local findings, operative and postoperative management factors. The secondary objectives are to evaluate the content and applicability of a consensus core set of AEs (CES) considering the patient's perspective, validate a severity classification for AEs, and quantify clinically-relevant ARCR outcomes up to 24 months postoperatively. Prognostic models will also be extended to all secondary outcomes.A sample size of 970 ARCR patients will be included; baseline patient demographics, history, shoulder status, magnetic resonance imaging based diagnosis and operative details will be recorded. Patient outcomes will be documented 6, 12 and 24 months after surgery. Clinical examinations at 6 and 12 months will include shoulder range of motion and strength (Constant Score), as well as the documentation of AEs. Tendon repair integrity status will be assessed by ultrasound examination at 12 months. Patient-reported outcome questionnaires at all follow-up time points will determine functional scores (Subjective Shoulder Value, Oxford Shoulder Score), anxiety and depression scores, working status, quality of life (EuroQol EQ-5D-5L), and AEs. All AEs will be documented according to the consensus CES and classified by their degree of severity; patients will rate the perceived severity and disturbance of experienced AEs. We will use the web-based REDCap data capture system for data management. Intensive central monitoring will be performed and investigator meetings will be coordinated during the study. The adapted AE severity classification will be validated. All data will be tabulated and prediction models will be developed using internationally supported methodology.This project will initiate the development of personalized risk predictions to support the surgical decision process in ARCR. The consensus CES may become an international reference for the reporting of complications in clinical studies and registers. The proposed study will foster the condition towards the development of a Swiss national ARCR register. Such a study and registry is an important step to increasing transparency in orthopedic surgery as requested by the federal strategy in healthcare "Health 2020". Methodological insights gained from this work will be easily transferable to similar initiatives in orthopedics.

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Influence of additional weight carrying on load-induced changes in glenohumeral translation in patients with rotator cuff tear - a translational approach

Research Project  | 4 Project Members

The shoulder is a unique joint: the primary stabilization by the rotator cuff muscles facilitates a large range of motion that is a prerequisite for many daily, occupational and recreational activities. Accordingly, injury to the rotator cuff greatly affects joint function and limits the patients' activities. Rotator cuff tears are a common shoulder injury that sometimes remain undiagnosed because of limited symptoms. However, altered shoulder biomechanics because of injury - even when only subtle - can lead to secondary damage and degeneration including tendinopathy or osteoarthritis. Because of the overlying soft tissue, measuring shoulder biomechanics is complex. Motion of the healthy shoulder primarily comprises rotation with very small to no translation because of stabilization through muscle activity and is affected by muscle cross sectional area (MCSA) and shoulder anatomy including the critical shoulder angle (CSA) and glenoid inclination (GI). Although often clinically observed, inconclusive changes in shoulder translation have been reported in patients with rotator cuff tear. However, to date it is unknown how additional handheld weight similar to situations during daily, occupational or recreational activities affects glenohumeral translation in patients with rotator cuff tear. Based on previous methods for assessing glenohumeral translation, we have developed an in vivo, simulation and ex vivo experimental framework for systematically modulating additional weight during a loading shoulder abduction test that we propose to employ in this study. This framework allows us to assess the dose-response relationship between additional weight and glenohumeral translation termed load-induced glenohumeral translation (liTr). We will address the following specific aims in in vivo, simulation and ex vivo experiments: understanding the biological variation in liTr; understanding the influence of disease pathology on liTr; understanding the potential compensation of rotator cuff tear by muscle activation and muscle size; and understanding the association of liTr and patient outcomes. Patients with rotator cuff tears and asymptomatic persons with similar age and sex distribution will be clinically assessed and complete a loading shoulder abduction test while collecting single plane fluoroscopy images. The same test will be repeated while 3-dimensional (3D) motion data and electromyographic data is collected. In the motion analysis test and in the fluoroscopy test, handheld weight will be applied. LiTr will be calculated as the slope of a regression of the negative distance of the glenohumeral centre of rotation (GHJC) to the acromion and studied in relation to patient's functional scores, MCSA, tear size and type, and the CSA and GI. Moreover, we will extent a previously developed shoulder simulator to integrate glenoid specimen, anterior and posterior aspects of the deltoid muscle and facilitate simulation of individual tendon rupture. Subsequently, we will use this shoulder simulator in simulation and ex vivo experiments to systematically study the effect of tear size and type, CSA and GI in sawbones and human cadaveric specimen. Finally, we will compare results of in vivo, simulation and ex vivo experiments and formulate specific recommendation for clinic and rehabilitation. This study can be considered as proof-of-concept of a potential diagnostic test (loading shoulder abduction test) for glenohumeral translation and will provide first evidence of a dose-response relationship between additional weight and glenohumeral translation. Moreover, the simulation and ex vivo experiments using a shoulder simulator allow the systematic investigation of mechanical compensation for injury to one or more rotator cuff muscles. The results of this study are relevant for diagnostics, treatment and rehabilitation planning in this population.