Florian Schmaranzer

Uniklinik Balgrist · Department of Radiology

Objectives To present our technique of diagnostic CT-guided ischiofemoral space injection and report on pain response, complications, and associated imaging findings in young patients with ischiofemoral impingement (IFI). Methods Retrospective case series of patients with a clinical diagnosis of IFI that underwent CT-guided IFS injection with loca...

Aims: Hip arthroscopy has gained prominence as a primary surgical intervention for symptomatic femoroacetabular impingement (FAI). This study aimed to identify radiological features, and their combinations, that predict the outcome of hip arthroscopy for FAI. Methods: A prognostic cross-sectional cohort study was conducted involving patients fro...

Objectives To compare the prevalence of femoral head decentration (FHD) on different MR imaging planes in patients undergoing direct/indirect hip MR arthrography (MRA) with asymptomatic controls and to evaluate its association with osseous deformities. Methods IRB-approved retrospective single-center study of symptomatic hips undergoing direct or...

Background data Computed Tomography (CT) is the gold standard for cervical spine (c-spine) evaluation. Magnetic resonance imaging (MRI) emerges due to its increasing availability and the lack of radiation exposure. However, MRI is costly and time-consuming, questioning its role in the emergency department (ED). This study investigates the added the...

Objectives The aim of this study was to compare deep learning reconstructed (DLR) 0.55 T magnetic resonance imaging (MRI) quality, identification, and grading of structural anomalies and reader confidence levels with conventional 3 T knee MRI in patients with knee pain following trauma. Materials and Methods This prospective study of 26 symptomati...

Background Hip arthroscopy with initial access to the peripheral compartment could reduce the risk of iatrogenic injury to the labrum and cartilage; furthermore, it avoids the need for large capsulotomies with separate portals for peripheral and central (intra-articular) arthroscopy. Clinical results of the peripheral-compartment-first technique re...

To validate 3D methods for femoral version measurement, we asked: (1) Can a fully automated segmentation of the entire femur and 3D measurement of femoral version using a neck based method and a head‐shaft based method be performed? (2) How do automatic 3D‐based computed tomography (CT) measurements of femoral version compare to the most commonly u...

Objectives Slipped capital femoral epiphyses (SCFE) is a common pediatric hip disease with the risk of osteoarthritis and impingement deformities, and 3D models could be useful for patient-specific analysis. Therefore, magnetic resonance imaging (MRI) bone segmentation and feasibility of 3D printing and of 3D ROM simulation using MRI-based 3D model...

Background Femoral version deformities have recently been identified as a major contributor to femoroacetabular impingement (FAI). An in-depth understanding of the specific labral damage patterns caused by femoral version deformities may help to understand the underlying pathomorphologies in symptomatic patients and select the appropriate surgical...

The objective was to use convolutional neural networks (CNNs) for automatic segmentation of hip cartilage and labrum based on 3D MRI. In this retrospective single-center study, CNNs were used to develop a fully automated segmentation model for hip cartilage and labrum from MRI. Direct hip MR arthrographies (01/2020-10/2021) were selected from 100 s...

Background There is limited evidence supporting the value of morphological parameters on post-reduction magnetic resonance imaging (MRI) to predict long-term residual acetabular dysplasia (RAD) after closed or open reduction for the treatment of developmental dysplasia of the hip (DDH). Methods We performed a retrospective study of 42 patients (47...

Objectives To identify preoperative degenerative features on traction MR arthrography associated with failure after arthroscopic femoroacetabular impingement (FAI) surgery. Methods Retrospective study including 102 patients (107 hips) undergoing traction magnetic resonance arthrography (MRA) of the hip at 1.5 T and subsequent hip arthroscopic FAI...

Objectives To assess the feasibility of flexion-abduction-external rotation (FABER) magnetic resonance imaging (MRI) of the hip to visualize changes in the ischiofemoral interval and ability to provoke foveal excursion over the acetabular rim. Methods IRB-approved retrospective single-center study. Patients underwent non-contrast 1.5-T hip MRI in...

Zusammenfassung Das femoroazetabuläre Impingement-Syndrom (FAIS) wird durch einen repetitiven mechanischen Konflikt zwischen Azetabulum und proximalem Femur insbesondere bei Flexion und Innenrotation hervorgerufen. Beim femoroazetabulären Impingement (FAI) vom Cam-Typ bewirkt eine Asphärizität am femoralen Kopf-Hals-Übergang die Induktion von Scher...

Femoroacetabular impingement (FAI) patients with reduced femoral version (FV) are poorly understood. The aim of this study is to assess (i) hip pain and range of motion, (ii) subjective satisfaction and (iii) subsequent surgeries of symptomatic patients who underwent rotational femoral osteotomies. A retrospective case series involving 18 patients...

More than half of SCFE patients treated with in-situ-pinning had absolute femoral retroversion on postoperative CT scans, ranging from 42% of mild SCFE to 67% of severe SCFE. Femoral retroversion was previously associated with anterior subspinehip impingement. This could help to evaluate subsequent surgery (such as derotationfemoral osteotomy). Rad...

Purposes Frequency of abnormal femoral and acetabular version (AV) and combinations are unclear in patients with developmental dysplasia of the hip (DDH). This study aimed to investigate femoral version (FV), the proportion of increased FV and femoral retroversion, and combined-version (CV, FV+AV) in DDH patients and acetabular-retroversion (AR)....

Background: Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) allows objective and noninvasive assessment of cartilage quality. An interim analysis 1 year after correction of femoroacetabular impingement (FAI) previously showed that the dGEMRIC index decreased despite good clinical outcome. Purpose: To evaluate dGEMRI...

Background: Traumatic cervical spine (c-spine) injuries account for 10% of all spinal injuries. The c-spine is prone to injury by blunt acceleration/deceleration traumas. The Canadian C-Spine rule and NEXUS criteria guide clinical decision-making but lack consensus on imaging modality when necessary. This study aims to evaluate the sensitivity and...

Objectives: Biological composite valve grafts (CVGs) are being performed more frequently, which increases the need for interventions treating bioprosthetic valve failure. The feasibility of valve-in-valve (ViV) procedures in this population is uncertain. This study aimed to assess changes in aortic root geometry and coronary height following CVG i...

Objective: To compare image quality and diagnostic performance of preoperative direct hip magnetic resonance arthrography (MRA) performed with gadolinium contrast agent and saline solution. Methods: IRB-approved retrospective study of 140 age and sex-matched symptomatic patients with femoroacetabular impingement, who either underwent intra-artic...

Background: Developmental dysplasia of the hip (DDH) is a known reason for hip pain for adolescents and young adults. Preoperative imaging is increasingly recognized as an important factor due to the recent advances in MR imaging. Objectives: The aim of this article is to give an overview of preoperative imaging for DDH. The acetabular version a...

Purpose Slipped capital femoral epiphysis is a common pediatric hip disease and was associated with femoral retroversion, but femoral version was rarely measured. Therefore, mean femoral version, mean femoral neck version, and prevalence of femoral retroversion were analyzed for slipped capital femoral epiphysis patients. Methods A retrospective o...

(1) Background: To evaluate the performance of a deep learning model to automatically segment femoral head necrosis (FHN) based on a standard 2D MRI sequence compared to manual segmentations for 3D quantification of FHN. (2) Methods: Twenty-six patients (thirty hips) with avascular necrosis underwent preoperative MR arthrography including a coronal...

Purpose The purpose of the study was to compare the post-reduction magnetic resonance imaging morphology for hips that developed residual acetabular dysplasia, hips without residual dysplasia, and uninvolved contralateral hips in patients with unilateral developmental dysplasia of the hip undergoing closed or open reduction and had a minimum 10-yea...

Aims: To compare (a) the change in radiological bony morphology between participants with femoroacetabular impingement (FAI) syndrome who underwent arthroscopic hip surgery compared to physiotherapist-led non-surgical care and (b) the change in radiological bony morphology between participants with FAI syndrome who underwent arthroscopic hip surge...

Background Different surgical techniques have been described for the treatment of knee dislocation (KD). Nonoperative approaches are frequently combined with surgical reconstruction using auto- or allograft. Purpose To evaluate the midterm results of primary surgical repair and suture augmentation to treat KD. Study Design Case series; Level of e...

Aims Frequency of abnormal femoral and acetabular version(AV) and combinations are unclear in patients with developmental dysplasia of the hip (DDH). This study aimed to investigate femoral version(FV), the proportion of increased FV and femoral retroversion, and combined-version(CV, FV+AV) in DDH patients and acetabular-retroversion(AR). Patients...

Background Acetabular retroversion is observed frequently in healed Legg–Calvé–Perthes disease (LCPD). Currently, it is unknown at which stage and with what prevalence retroversion occurs because in non-ossified hips, retroversion cannot be measured with standard radiographic parameters. Methods In a retrospective, observational study; we examined...

Posterior extraarticular ischiofemoral hip impingement was associated with increased femoral version in female patients. The Purpose of this study was to investigate frequency of impingement in maximal extension in female patients with increased femoral version.

Aims To evaluate how abnormal proximal femoral anatomy affects different femoral version measurements in young patients with hip pain. Methods First, femoral version was measured in 50 hips of symptomatic consecutively selected patients with hip pain (mean age 20 years (SD 6), 60% (n = 25) females) on preoperative CT scans using different measurem...

Background Symptomatic patients with femoroacetabular impingement (FAI) have limitations in daily activities and sports and report the exacerbation of hip pain in deep flexion. Yet, the exact impingement location in deep flexion and the effect of femoral version (FV) are unclear. Purpose To investigate the acetabular and femoral locations of intra...

Purpose Preservation surgery can halt the progress of joint degradation, preserving the life of the hip; however, outcome depends on the existing cartilage quality. Biochemical analysis of the hip cartilage utilizing MRI sequences such as delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), in addition to morphological analysis, can be used to d...

Aims The frequency of severe femoral retroversion is unclear in patients with femoroacetabular impingement (FAI). This study aimed to investigate mean femoral version (FV), the frequency of absolute femoral retroversion, and the combination of decreased FV and acetabular retroversion (AR) in symptomatic patients with FAI subtypes. Methods A retros...

Frequencies of combined abnormalities of femoral version (FV) and acetabular version (AV) and of abnormalities of the McKibbin index are unknown. To investigate the prevalence of combined abnormalities of FV and AV and of abnormalities of the McKibbin index in symptomatic patients with femoroacetabular impingement (FAI), a retrospective, Institutio...

Zusammenfassung Instabilität und Impingement stellen die Hauptpathomechanismen dar, die bereits bei jungen Patienten durch erhöhten mechanischen Stress zu chondrolabralen Schäden, schmerzhafter Bewegungseinschränkung und frühzeitiger Coxarthrose führen können. Ziele der gelenkerhaltenden Chirurgie an der Hüfte sind die Korrektur der knöchernen Defo...

Objectives: The crossover-sign (COS) is a radiographic sign for diagnosis of acetabular-retroversion(AR) in patients with femoroacetabular-impingement (FAI) but overestimates AR. Three signs combined with retroversion-index (RI) could potentially improve diagnostic-accuracy. Aims: (1)To calculate central acetabular-version (AV, CT/MRI) in patien...

Objective To assess whether subchondral drilling of acetabular cartilage flaps during femoroacetabular impingement (FAI) surgery improves (1) acetabular dGEMRIC indices and (2) morphologic magnetic resonance imaging (MRI) scores, compared with hips in which no additional treatment of cartilage lesions had been performed; and (3) whether global dGEM...

The etiology of hallux rigidus remains a controversial issue in foot and ankle surgery, i.e. the relationship between metatarsus primus elevatus (MPE) and hallux rigidus. The purpose of this study was to evaluate several radiographic parameters including first metatarsal elevation in patients with hallux rigidus compared to a matched control group....

Objectives To compare the prevalence of pre- and postoperative osseous deformities and intra-articular lesions in patients with persistent pain following arthroscopic femoroacetabular impingement (FAI) correction and to identify imaging findings associated with progressive cartilage damage. Methods Retrospective study evaluating patients with hip...

Background Dynamic 3-dimensional (3D) simulation of hip impingement enables better understanding of complex hip deformities in young adult patients with femoroacetabular impingement (FAI). Deep learning algorithms may improve magnetic resonance imaging (MRI) segmentation. Purpose (1) To evaluate the accuracy of 3D models created using convolutiona...

Aims The effect of pelvic tilt (PT) and sagittal balance in hips with pincer-type femoroacetabular impingement (FAI) with acetabular retroversion (AR) is controversial. It is unclear if patients with AR have a rotational abnormality of the iliac wing. Therefore, we asked: are parameters for sagittal balance, and is rotation of the iliac wing, diffe...

Unsupervised domain adaptation (UDA) for cross-modality medical image segmentation has shown great progress by domain-invariant feature learning or image appearance translation. Feature-level adaptation based methods learn good domain-invariant features in classification tasks but usually cannot detect domain shift at the pixel level and are not ab...

Background Arthroscopic surgery for femoroacetabular impingement syndrome (FAI) is known to lead to self-reported symptom improvement. In the context of surgical interventions with known contextual effects and no true sham comparator trials, it is important to ascertain outcomes that are less susceptible to placebo effects. The primary aim of this...

The primary purpose was to answer the following question: What is the location and pattern of necrosis and associated chondrolabral lesions and can they be accurately detected on traction MR arthrography compared with intra-operative findings in patients undergoing hip preservation surgery for femoral head necrosis (FHN)? Retrospective, diagnostic...

Preoperative evaluation of the pathomorphology is crucial for surgical planning, including radiographs as the basic modality and magnetic resonance imaging (MRI) and case-based additional imaging (e.g. 3D-CT, abduction views). Hip arthroscopy (HAS) has undergone tremendous technical advances, an immense increase in use and the indications are getti...

Background Posterior extra-articular hip impingement has been described for valgus hips with increased femoral version (FV). These patients can present clinically with lack of external rotation (ER) and extension and with a positive posterior impingement test. But we do not know the effect of the combination of deformities, and the impingement loca...

Background Anterior femoroacetabular impingement (FAI) is associated with labral tears and acetabular cartilage damage in athletic and young patients. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is an imaging method for detecting early damage to cartilage. Purpose We evaluated the following questions: (1) What is...

Background Often used for T1 mapping of hip cartilage, three-dimensional (3D) dual-flip-angle (DFA) techniques are highly sensitive to flip angle variations related to B1 inhomogeneities. The authors hypothesized that 3D magnetization-prepared 2 rapid gradient-echo (MP2RAGE) MRI would help provide more accurate T1 mapping of hip cartilage at 3.0 T...

OBJECTIVE. Imaging plays a critical role in the assessment of patients with femoroacetabular impingement (FAI). With better understanding of the underlying pathomechanics and advances in joint-preserving surgery, there is an increasing need to define the most appropriate imaging workup. The purpose of this article is to provide guidance on best pra...

Patient-specific 3D models for patients with severe SCFE facilitate diagnosis and surgical planning simulating the range of motion and location of impingement. Femoral impingement is mostly located anterior. This study could aid in preoperative planning and surgical decision making e.g.what kind of operation should be performed for patients with se...

Automatic MRI-based 3D models can replace CT-based 3D models for patients of childbearing age with hip dysplasia and FAI. Based on these excellent results, we intend to change our clinical practice and we will use automatic reconstruction of MR-based 3D models for future clinical routine instead of CT-based 3D models. This allows radiation-free and...

Pincer FAI can be caused by acetabular overcoverage (protrusio acetabuli) or malorientation (acetabular retroversion). Both can cause anterior hip pain and hip impingement. Using patient-specific 3D models of the patients, 3D simulation of hip impingement showed intra- and extraarticular subspine hip impingement in patients with acetabular retrover...

Deep learning provides fast and automatic bone segmentation for patient-specific 3D models of the hip joint. These 3D models can be used for computer-assisted diagnosis of hip dysplasia and femoroacetabular impingement (FAI). This method allows fast preoperative planning of hip preserving surgery such as hip arthroscopy or open treatment.

At minimum 10 year follow up after prophylactic pinning of the contralateral radiographically normal hip the vast majority of the patients can expect an excellent functional hip specific outcome. However, patients with unilateral SCFE should still be considered to be at risk of developing cam FAI in the contralateral normal hip despite prophylactic...

The modified Dunn procedure for severe SCFE largely corrected slip deformities with little apparent risk of progression to avascular necrosis, OA, THA or hip arthrodesis and high hip scores at longterm followup . However, AVN occurred in 2 hips (5%) and secondary impingement deformities persisted in some hips and of those some underwent further sur...