Florian Schmaranzer

Improving visualization of the central compartment of the hip with direct MR arthrography under axial leg traction: a feasibility study.

RATIONALE AND OBJECTIVES To evaluate the feasibility of a modified approach for direct magnetic resonance (MR) arthrography of the hip under leg traction in achieving a sufficient femoroacetabular interface and improving the visualization of the ligamentum teres. MATERIALS AND METHODS Forty-six MR arthrograms of 44 patients who underwent MR arthrography with and without leg traction were included into the study. Traction approach included injection of 18-27 mL of fluid (local anesthetic, contrast agent), application of weight-adapted traction load (15-23 kg), and the use of a supporting plate. Patients were instructed to report on pain and complications with an integer pain scale. Joint distraction was measured on coronal images obtained with and without traction, and two radiologists independently evaluated whether femoroacetabular cartilage layers and the ligamentum teres could be seen as distinct entities. McNemar test was used and interobserver agreement was assessed. RESULTS No patient asked for termination of the examination. There were no cases of neuropraxia. Mean difference in distraction was 3.7 mm/3.6 mm (reader 1/reader 2). Cartilage layers could be seen as distinct entities in 43/43 (93.5%/93.5%) and 6/8 (13%/17.4%) of the joints with/without traction (P < .001/P < .001), respectively. The ligamentum teres could be differentiated in 33/30 (71.7%/65.2%) cases with traction, in 33/30 (71.7%/65.2%) cases without traction (P < .999/P < .999), and in 40/37 (87%/80.4%) cases with both the techniques combined. CONCLUSIONS Traction MR arthrography is safe and technically feasible. It enabled the differentiation between femoroacetabular cartilage layers in most cases. Visualization of the ligamentum teres was optimal by combining imaging with both modalities.

Prevalence of Femoral and Acetabular Version Abnormalities in Patients With Symptomatic Hip Disease: A Controlled Study of 538 Hips.

Background: Variations in femoral and acetabular version are becoming increasingly recognized as contributing factors to the development of hip pain in patients with femoroacetabular impingement (FAI) and hip dysplasia. It is still unknown what the true prevalence of these rotational abnormalities is in this patient population. Purpose: To determine (1) the prevalence of femoral version abnormalities in symptomatic hips with FAI and hip dysplasia, (2) the prevalence of combined abnormalities of femoral and acetabular version in these patients, and (3) which specific hip morphologies are associated with abnormalities of femoral version. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 462 symptomatic patients (538 hips) were included who had hip pain attributed to FAI or hip dysplasia and who presented to our tertiary referral center for hip preservation surgery between 2011 and 2015. We retrospectively examined femoral and acetabular version among 11 subgroups with predefined hip morphologies and compared findings with a control group. The allocation to each subgroup was based on morphologic reference values for femoral head coverage, lateral center edge angle, alpha angle, and neck-shaft angle calculated on plain radiographs. Results: Of the 538 hips included, 52% were found to have abnormal femoral version; severe abnormalities were found in 17%. Severely decreased femoral version (<0°) was found in 5%; moderately decreased femoral version (0°-10°), in 17%; moderately increased femoral version (26°-35°), in 18%; and severely increased femoral version (>35°), in 12%. The most frequent abnormal combination was increased femoral version combined with normal acetabular version (22%). We found significantly lower mean femoral version for the cam-type FAI group (15°) and significantly higher mean femoral version for the Perthes hips (32°; ie, Legg-Calvé-Perthes disease) as compared with the control group (22°). The mean femoral version of the study group was 19°; for male patients, 15°; and for female patients, 22°. Conclusion: Abnormalities in femoral version are highly prevalent in patients with hip pain who are eligible for hip preservation surgery, and severe abnormalities are prevalent in 1 of 6 patients (17%). Based on these results, the evaluation of young patients with hip pain should always include an assessment of femoral version and acetabular version to best decide what treatment approach should be undertaken to optimize outcomes.

MR arthrography of the hip with and without leg traction: Assessing the diagnostic performance in detection of ligamentum teres lesions with arthroscopic correlation.

OBJECTIVES To retrospectively assess the diagnostic performance of hip MR arthrography with and without traction in detecting ligamentum teres (LT) lesions with arthroscopic correlation and to evaluate the effect of traction on the imaging appearance of the LT. METHODS 73 MR arthrograms (73 consecutive patients, mean age, 34.5 years; range, 14-55 years) obtained without and with leg traction (application of 15-23 kg, use of a supporting plate for the contralateral leg) were included. Two blinded readers independently evaluated LT lesions on MR arthrograms on separate occasions: coronal images without traction; coronal images with traction; a multiplanar traction protocol. MR findings were correlated with arthroscopic records. Sensitivity/specificity of traction and non-traction imaging was compared on coronal images with the exact McNemar test. Imaging appearance of the LT with and without traction was assessed in consensus and compared on coronal images using McNemar and McNemar-Bowker tests. (p<0.05, * corrected for type I error). RESULTS With arthroscopy 29 (40%) LT lesions were identified in 73 patients. Sensitivity was 72%/90% (without traction/with traction; p=0.25*), specificity was 89%/77% (p=0.25*) for reader 1 in assessing coronal images and for reader 2 sensitivity was 59%/86% (p=0.044*) and specificity was 93%/82% (p=0.25*). Alterations in fiber orientation, signal intensity, surface, dimension, fiber continuity after application of traction were observed in 33/73 (45%, p=0.002*), 6/73 (8%, p=0.223), 9/73 (12%, p=0.36*), 6/73 (8%, p=0.031) respectively 9/73 (12%, p=0.003) cases. Traction-related alterations in at least one criterion were observed in 41/73 (56%) cases. CONCLUSION Application of traction can considerably alter the imaging appearance of the LT and resulted in higher rates of true-positive and false-positive findings compared to conventional MR arthrography.

The modified Dunn procedure for slipped capital femoral epiphysis: the Bernese experience

Abstract Purpose Based on previous investigations on the vascular blood supply to the femoral head, a technique for anatomical reduction after slipped capital femoral epiphysis was developed. This technique is a modification of the original technique by Dunn using a retinacular soft-tissue flap. This allows the visual control of the epiphyseal vascular blood supply. We report the experience at the inventor’s institution with a critical discussion of the available literature. Methods Using a trochanteric osteotomy for surgical dislocation of the hip, a retinacular soft tissue flap is created containing the deep branch of the medial femoral circumflex artery, the external rotators and the capsule. The femoral epiphysis can be mobilised safely and reduced on the femoral neck after resection of the almost constantly present reactive metaphyseal callus. Results In our institution, the rate of avascular necrosis with 2% is comparably low to Dunn’s original results. It is only present in cases where no bleeding was already evident before reduction of the epiphysis. The ten-year long-term results are favorable in these cases with a good functional result and only little progression of osteoarthritis. However, other authors have reported higher rates of avascular necrosis up to 24% in their initial experience. Conclusions In experienced hands using the correct meticulous surgical technique, the results are favorable regarding the rates of avascular necrosis, the functional outcome and the development of radiographic osteoarthritis – even in acute and severe cases. Avascular necrosis is rare but can be observed if there is no evidence of intra-operative femoral head perfusion before and after reduction of the epiphysis.

Imaging of femoroacetabular impingement-current concepts

Following the recognition of femoroacetabular impingement (FAI) as a clinical entity, diagnostic tools have continuously evolved. While the diagnosis of FAI is primarily made based on the patients’ history and clinical examination, imaging of FAI is indispensable. Routine diagnostic work-up consists of a set of plain radiographs, magnetic resonance imaging (MRI) and MR-arthrography. Recent advances in MRI technology include biochemically sensitive sequences bearing the potential to detect degenerative changes of the hip joint at an early stage prior to their appearance on conventional imaging modalities. Computed tomography may serve as an adjunct. Advantages of CT include superior bone to soft tissue contrast, making CT applicable for image-guiding software tools that allow evaluation of the underlying dynamic mechanisms causing FAI. This article provides a summary of current concepts of imaging in FAI and a review of the literature on recent advances, and their application to clinical practice.

Intra-articular Lesions: Imaging and Surgical Correlation.

The past 2 decades have seen a substantial increase in hip joint preserving procedures, primarily secondary to not only hip dysplasia, but the recognition and description of femoroacetabular impingement (FAI), and its association with chondral lesions, as a potentially pre-arthritic condition. Morphological magnetic resonance imaging (MRI) plays an essential role in the preoperative assessment of osseous deformities and in particular of the resulting joint degeneration. An accurate descriptive report of chondrolabral lesions is warranted describing the tear pattern, size, localization, and extension of the lesions. This is important because different damage patterns and localization of the lesions may determine the surgical approach. The current imaging standard is direct magnetic resonance arthrography (MRA) with a small field of view, with acquisition of radial images in addition to the classic coronal, sagittal, and axial-oblique images. Early cartilage damage detected on direct MRA obtained with or without traction can predict long-term failure after FAI surgery.

Impingement of the hip

Femoroacetabular impingement (FAI) describes the repetitive painful contact between the acetabulum, the pelvis and the proximal femur. This bony abutment can lead to a characteristic pattern of chondrolabral damage and is one of the main etiological factors in the development of juvenile osteoarthritis of the hip joint. This article describes the current treatment concepts of FAI and the radiological assessment including an overview of standard measurement methods, coxometric parameters and cut-off values. Furthermore, the authors stress the importance of a profound understanding of the entire configuration of the pelvis and the dynamic interplay of its components.ZusammenfassungDas Konzept des femoroazetabulären Impingements (FAI) beschreibt den schmerzhaften repetitiven ossären Anschlag zwischen Azetabulum respektive Becken und proximalem Femur. Es kann zu einer charakteristischen Schädigung an den Gelenkbinnenstrukturen führen und stellt somit eine Hauptursache für die Entstehung der juvenilen Coxarthrose dar. Der vorliegende Artikel beinhaltet neben der Beschreibung des aktuellen Behandlungskonzepts beim FAI die entsprechende radiologische Abklärung inklusive einer Übersicht über Standardmessmethoden und coxometrische Grenzwerte und legt den Fokus auf das Verständnis der Gesamtmorphologie bei dieser komplexen Fragestellung.AbstractFemoroacetabular impingement (FAI) describes the repetitive painful contact between the acetabulum, the pelvis and the proximal femur. This bony abutment can lead to a characteristic pattern of chondrolabral damage and is one of the main etiological factors in the development of juvenile osteoarthritis of the hip joint. This article describes the current treatment concepts of FAI and the radiological assessment including an overview of standard measurement methods, coxometric parameters and cut-off values. Furthermore, the authors stress the importance of a profound understanding of the entire configuration of the pelvis and the dynamic interplay of its components.

Impingement der Hüfte

Femoroacetabular impingement (FAI) describes the repetitive painful contact between the acetabulum, the pelvis and the proximal femur. This bony abutment can lead to a characteristic pattern of chondrolabral damage and is one of the main etiological factors in the development of juvenile osteoarthritis of the hip joint. This article describes the current treatment concepts of FAI and the radiological assessment including an overview of standard measurement methods, coxometric parameters and cut-off values. Furthermore, the authors stress the importance of a profound understanding of the entire configuration of the pelvis and the dynamic interplay of its components.ZusammenfassungDas Konzept des femoroazetabulären Impingements (FAI) beschreibt den schmerzhaften repetitiven ossären Anschlag zwischen Azetabulum respektive Becken und proximalem Femur. Es kann zu einer charakteristischen Schädigung an den Gelenkbinnenstrukturen führen und stellt somit eine Hauptursache für die Entstehung der juvenilen Coxarthrose dar. Der vorliegende Artikel beinhaltet neben der Beschreibung des aktuellen Behandlungskonzepts beim FAI die entsprechende radiologische Abklärung inklusive einer Übersicht über Standardmessmethoden und coxometrische Grenzwerte und legt den Fokus auf das Verständnis der Gesamtmorphologie bei dieser komplexen Fragestellung.AbstractFemoroacetabular impingement (FAI) describes the repetitive painful contact between the acetabulum, the pelvis and the proximal femur. This bony abutment can lead to a characteristic pattern of chondrolabral damage and is one of the main etiological factors in the development of juvenile osteoarthritis of the hip joint. This article describes the current treatment concepts of FAI and the radiological assessment including an overview of standard measurement methods, coxometric parameters and cut-off values. Furthermore, the authors stress the importance of a profound understanding of the entire configuration of the pelvis and the dynamic interplay of its components.