Adult Hip Radiography: Lines and angles

Transcription

1 Adult Hip Radiography: Lines and angles Poster No.: P-0209 Congress: ESSR 2017 Type: Educational Poster Authors: A. L. Proença, A. P. Caetano, L. Bogalho; Lisbon/PT Keywords: Education and training, Education, Conventional radiography, Musculoskeletal bone, Bones DOI: /essr2017/P-0209 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 49

2 Learning objectives To describe the most used incidences in conventional radiology assessment of the hip joint. To review and illustrate the most important lines and angles for evaluation of normal hip anatomy and alignment. Background The hip joint is a synovial joint between the acetabulum of the pelvis and the head of the femur, which connects the axial skeleton with the lower extremity. Conventional radiography is widely used in the study of hip disease because of its availability, reliability and low cost. The most performed incidence is anteroposterior view (AP view). Other radiographic projections (cross-table lateral, Dunn, frog-leg lateral and false-profile) are used when certain pathologies are suspected. The anteroposterior pelvic and false-profile views provide information regarding acetabular morphology. On the other hand, frog-leg lateral and Dunn views highlight anatomy of the proximal part of the femur. It is important to recognize parameters for plain radiographic assessment to ensure that patient positioning was appropriate and the reliability of radiographies to serve as diagnostic tool. Radiographic views Anteroposterior pelvic view (unilateral or bilateral) Frog-leg lateral view 45 or 90 Dunn view Cross-table lateral view Page 2 of 49

3 False-profile view Anterior or posterior oblique view (Judet view) Anteroposterior Pelvic View Indications: Routine, fractures, joint dislocations, degenerative disease and bone lesions. Evaluation Criteria Coccyx aligned with the pubic symphysis. Symmetrical iliac wings, obturator ring and radiographic teardrops. Lesser trochanters should not be visible. Fig. 1: Anteroposterior view of the pelvis Page 3 of 49

4 References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Fig. 2: AP Positioning - Patient supine on the x-ray table. - Both lower extremities oriented in 15 of medial rotation (to maximize the length of the femoral neck) References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Frog-Leg Lateral View Indications: non-trauma hip, developmental dysplasia of hip, slipped capital femoral epiphysis, assessment of head-neck junction. Evaluation Criteria Greater trochanter appears superimposed over the femoral neck, which appear foreshortened. Page 4 of 49

5 Fig. 3: Frog-leg lateral view References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Page 5 of 49

6 Fig. 4: Frog-leg lateral view Positioning - Patient supine on the x-ray table. - Feet together (if bilateral), affected knee flexed (30-40º), thighs abducted (45º) and externally rotated. References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT 45 or 90 Dunn View Page 6 of 49

7 Indications: Diagnosis of femoral-acetabular impingement (the prefered view to demonstrate femoral head-neck asphericity). Evaluation Criteria Relationship between the acetabulum and femoral head well demonstrated. Anterior superior iliac spine and proximal shaft of femur included in image. Page 7 of 49

8 Fig. 5: Dunn view at 45º References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Page 8 of 49

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10 Fig. 6: Dunn view at 45º Positioning: - Patient supine on the x-ray table. - Modified Dunn view uses 45º hip flexion, when 90º is not possible. References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Fig. 7: Dunn view at 45º References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Fig. 8: Dunn view at 90º Positioning - Patient supine on the x-ray table. - Pelvis in neutral rotation while symptomatic hip joint is flexed 90º and abducted 20º. References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Page 10 of 49

11 Cross-table Lateral View Indications: expose the anterolateral surface of the femoral head-neck transition. Evaluation Criteria Greater trochanter should not be seen to overhang posteriorly. Visible lesser trochanter indicates adequate internal rotation. Fig. 9: Cross-table lateral view References: 2015 by Korean Hip Society Page 11 of 49

12 Fig. 10: Cross-table lateral view Positioning - Patient supine on the x-ray table. Contralateral hip and knee flexed beyond Symptomatic limb internally rotated 15. Page 12 of 49

13 References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT False-Profile View (Lequesne view) Indications: assessment of femoroacetabular impingement (visibility of the medial and anterosuperior head coverage) and acetabular dysplasia. Evaluation Criteria Distance between femoral heads should correspond to the diameter of a femoral head. Profile of head and proximal femur but not the acetabulum. Page 13 of 49

14 Fig. 11: False-Profile view References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Page 14 of 49

15 Fig. 12: False-Profile view Positioning - Patient in orthostatic position. - Affected hip against the cassette. - Pelvis rotated 65 anteriorly in relation to the cassette References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Anterior or Posterior oblique View (Judet view) Indications: Visualization of the anterior or posterior margins of the acetabulum (evaluate acetabular fracture or pelvis injury). Evaluation Criteria Downside: Posterior oblique position demonstrates the posterior column (ilioischial) and anterior acetabular rim. Upside: Anterior oblique position demostrates the anterior column (iliopubic) and posterior acetabular rim. The obturador foramen is also visualized. Proper degree of obliquity is shown as an open and uniform hip joint space at the rim of acetabulum and femoral head. Page 15 of 49

16 Fig. 13: Judet view. Right posterior oblique (downside) References: 2015 by Korean Hip Society Page 16 of 49

17 Fig. 14: Image 13: Judet view Positioning - Patient in a 45 oblique position. Centered on the downside (affected side down. - Centered on the upside (affected side up). References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Salvar Salvar Salvar Images for this section: Fig. 1: Anteroposterior view of the pelvis Page 17 of 49

18 Fig. 2: AP Positioning - Patient supine on the x-ray table. - Both lower extremities oriented in 15 of medial rotation (to maximize the length of the femoral neck) Page 18 of 49

19 Fig. 3: Frog-leg lateral view Fig. 4: Frog-leg lateral view Positioning - Patient supine on the x-ray table. - Feet together (if bilateral), affected knee flexed (30-40º), thighs abducted (45º) and externally rotated. Page 19 of 49

20 Fig. 5: Dunn view at 45º Page 20 of 49

21 Page 21 of 49

22 Fig. 6: Dunn view at 45º Positioning: - Patient supine on the x-ray table. - Modified Dunn view uses 45º hip flexion, when 90º is not possible. Fig. 7: Dunn view at 45º Fig. 8: Dunn view at 90º Positioning - Patient supine on the x-ray table. - Pelvis in neutral rotation while symptomatic hip joint is flexed 90º and abducted 20º. Page 22 of 49

23 Fig. 9: Cross-table lateral view Page 23 of 49

24 Fig. 10: Cross-table lateral view Positioning - Patient supine on the x-ray table. Contralateral hip and knee flexed beyond Symptomatic limb internally rotated 15. Page 24 of 49

25 Fig. 11: False-Profile view Page 25 of 49

26 Fig. 12: False-Profile view Positioning - Patient in orthostatic position. - Affected hip against the cassette. - Pelvis rotated 65 anteriorly in relation to the cassette Page 26 of 49

27 Fig. 13: Judet view. Right posterior oblique (downside) Page 27 of 49

28 Fig. 14: Image 13: Judet view Positioning - Patient in a 45 oblique position. - Centered on the downside (affected side down. - Centered on the upside (affected side up). Page 28 of 49

29 Imaging findings OR Procedure Details There are multiple lines and angles described in hip radiographic evaluation which provide diagnostic clues for several disorders (congenital, acquired or degenerative). Lines and Angles for Radiographic Evaluation of Hip Joint 1. Acetabular index 2. Alpha angle 3. Center-edge angle of Wiberg 4. Femoral neck angle (CCD angle) 5. Hip joint space 6. Ilioischial line (Köhler line) 7. Iliopectineal line 8. Shenton s line 9. Skinner's (femoral angle) line 10. Teardrop distance 11. Tönnis angle 1. Acetabular index (or Acetabular angle of Sharp) Indication: Measures acetabular inclination or opening and evaluates acetabular depth in potential developmental dysplasia of the hip. Projection: Anteroposterior pelvic view. Measurement: Angle formed between an horizontal line at the inferior aspect of both pelvic teardrops (A) and a line from the inferior margin of the teardrop to the lateral margin of acetabular roof (B). Criteria: Angle of intersection should not exceed standards based on age. In adults, the normal range is 33-38º. Angle above 47º suggests acetabular dysplasia and neuromuscular disorders. Values between 39-46º are indeterminate. Shallow angle is seen in Down syndrome and achondroplasia. Page 29 of 49

30 Fig. 15: Acetabular angle References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT 2. Alpha Angle Indication: Evaluation of anterior femoral head-neck junction shape in the assessment of femoroacetabular impingement. Projection: Cross-table lateral view of the hip. Measurement: Angle between a line along the femoral neck axis (A) and a line from the center of the femoral head to the transition of the femoral head into the femoral neck (neck radius exceeds head radius) (B). Criteria: Normal angle <55º. If > 55 degrees then associated with CAM type femoroacetabular impingement. Nowadays this angle is more used in MRI. Page 30 of 49

31 Fig. 16: Alpha angle References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT 3. Center-edge angle of Wiberg (or Lateral centre-edge (LCE) angle) Indication: Assess superolateral coverage provided by acetabular roof. Evaluation of residual hip dysplasia in children and adults. Projection: Anteroposterior pelvic view. Measurement: Angle formed between a vertical line through the center of the femoral head (A) and a line from the center of the femoral head, passing through the most superolateral margin of the acetabulum (B). Criteria: Normal angle must be above 25 degrees. Values of 20-25º are considered borderline. Elevated angles are associated with protusio acetabuli, but this is not the most accurate measurement method. Angle <20º is diagnostic of hip dysplasia. Page 31 of 49

32 Fig. 17: Center-edge angle of Wiberg (yellow) and Femoral angle (blue) References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT 4. Femoral neck angle (or Caput-collum-diaphyseal angle (CCD angle)) Indication: Evaluate hip alignment. Projection: Anteroposterior pelvic view. Measurement: Angle formed between the lines along the axis of femoral neck (C) and shaft (D) Criteria: Normal angle if intersection about 125 degrees. Coxa vara- angle less than 120 degrees. Coxa valga - angle more than 130 degrees. Fig. 17 on page Hip joint space Indication: Evaluation of hip joint space. Projection: Anteroposterior pelvic view. Page 32 of 49

33 Measurement: Distance between the cortex of the femoral head and the acetabulum, superiorly (s), axially (a) and medially (m). Criteria: Distance should not exceed 6 mm superiorly (s), 7 mm axially (a), or 13 mm medially (m). Wider distance is associated with hip joint effusion. The superior joint space is usually reduced by degenerative diseases. The axial space is commonly narrowed by inflammatory arthritis. The medial space is affected by both. Fig. 18: Normal hip joint spaces: s -superior, a - axial, m - medial References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT Page 33 of 49

34 Fig. 19: Patient with ostheoarthritis showing reduced hip spaces, more pronounced in the superior and medial joint space. References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT 6. Ilioischial line (or Köhler's line) Page 34 of 49

35 Indication: Evaluation of posterior column of the pelvis. Projection: Anteroposterior pelvic view. Measurement: Line along the outer border of the obturator foramen to the medial border of the iliac wing. It should pass through the acetabular teardrop. Criteria: Medial acetabular wall should not extend medially to this line. Coxa profunda - medial acetabular wall extended medial to the ilioischial line. Protusio acetabuli - acetabulum and femoral head projected medial to ilioischial line. Protusio acetabuli can be primary or secondary to rheumatoid or degenerative arthritis, Paget's disease, osteogenesis imperfecta, and idiopathic or other bone-softening disorders. If line is disrupted, consider posterior column fracture of the acetabulum. Fig. 20: Ilioischial line (yellow) and iliopectineal line (green) References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT 7. Iliopectineal line Indication: Evaluation of anterior column. Page 35 of 49

36 Projection: Anteroposterior pelvic view. Measurement: A linear bony ridge extending from the medial border of the iliac wing, along the superior border of the superior pubic ramus, ending at the pubic symphysis, defining the anterior column of the pelvis. Criteria: Smooth and continuous line. If disrupted, consider anterior column fracture of the acetabulum. Thickening of this line is associated with Paget disease, familial idiopathic hyperphosphatasia, metabolic or neoplasic conditions. Fig. 20 on page Shenton's hip line Indication: Evaluation of femoral neck integrity and alignment. Projection: Anteroposterior pelvic view. Measurement: Line along the inferior border of the superior pubic ramus and inferomedial border of the femural neck. Criteria: Smooth and continuous line. Disruption of this line is associated with hip dislocation, femoral neck fracture, and slipped capital femoral epiphysis. Fig. 22: Left - Intact Shenton s line. Right - Disruption of Shenton s line in a transtrochanteric fracture. References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT 9. Skinner's line Page 36 of 49

37 Indication: Assessment of relationship of the fovea capitis to the trochanteric line. Projection: Anteroposterior pelvic view. Measurement: Line along the longitudinal femoral shaft axis (A). Perpendicular line tangential to the tip of the greater trochanter (B). Criteria: The perpendicular line should pass through or below the fovea capitis. Hip joint abnormality if line is found above the fovea capitis; suspect fracture or bone-softening conditions causing coxa vara. Fig. 23: Skinner s line References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT 10. Teardrop distance Indication: Useful to evaluate for hip joint effusion or for hip dysplasia. Projection: Anteroposterior pelvic view. Page 37 of 49

38 Measurement: Distance between medial aspect of the femoral head and the lateral edge of the pelvic teardrop. Criteria: Distance should not exceed 11mm. Contralateral side should not differ more than 2mm. Waldenström's sign - discrepancy between and right and left teardrop distance is >2mm. Wider distance is a non-specific sign of hip joint effusion. Fig. 24: Symmetrical Teardrop distance (yellow). Tönnis angle (blue) References: Radiology, Centro Hospitalar Lisboa Central, Hospital de Curry Cabral Lisbon/PT 11. Tönnis angle (or Index of the Weightbearing Zone or Horizontal toit externe (HTE) angle) Indication: Measures inclination of weight bearing zone (acetabular roof), giving an indirect measure of femoral incongruence. Projection: Anteroposterior pelvic view. Measurement: Angle formed between a horizontal running through the most inferior point of the sclerotic acetabular sourcil (A) and a line extending from the medial to lateral edges of the sourcil (B). Criteria Normal: 0-10º. Measurement greater than 10 is a radiographic sign of hip dysplasia. Acetabuli with increased Tönnis angles are subject to structural instability, whereas those with decreased Tönnis angles are at risk for Pincer type femoroacetabular impingement. Fig. 24 on page 47 Page 38 of 49

39 Salvar Salvar Images for this section: Fig. 15: Acetabular angle Page 39 of 49

40 Fig. 16: Alpha angle Page 40 of 49

41 Fig. 17: Center-edge angle of Wiberg (yellow) and Femoral angle (blue) Page 41 of 49

42 Fig. 18: Normal hip joint spaces: s -superior, a - axial, m - medial Page 42 of 49

43 Fig. 19: Patient with ostheoarthritis showing reduced hip spaces, more pronounced in the superior and medial joint space. Page 43 of 49

44 Fig. 20: Ilioischial line (yellow) and iliopectineal line (green) Page 44 of 49

45 Fig. 21: Protusio acetabuli with disruption of Köhler line Page 45 of 49

46 Fig. 22: Left - Intact Shenton s line. Right - Disruption of Shenton s line in a transtrochanteric fracture. Page 46 of 49

47 Fig. 23: Skinner s line Fig. 24: Symmetrical Teardrop distance (yellow). Tönnis angle (blue) Page 47 of 49

48 Conclusion Conventional radiology is the chosen method of assessment of the hip joint. The radiologist should be familiar with the normal appearance of the hip joint and ensure that the patient positioning was appropriate. Radiographic measurements are a useful tool to evaluate normal anatomy and recognize signs of pathology. Nevertheless, an accurate diagnosis can only be obtained by interpreting radiographic findings together with the patient history and physical examination. References 1 - Bontrager K. Textbook of Radiologic positioning and related anatomy Mosby Elsevier; 2 - Campbell SEl. Radiography of the Hip: Lines, Signs, and Patterns of Disease Seminars in Roentgenology; 3 - Clohisy JC, Carlisle JC,et al. A Systematic Approach to the Plain Radiographic Evaluation of the Young Adult Hip The Journal of Bone and Joint Surgery; 4 - Keats TE. Atlas de Medidas Radiologicas. Mosby Elsevier España; 5 - Lim SJ, Park YS. Plain Radiography of the Hip: A Review of Radiographic Techniques and Image Features. Hip Pelvis. Sep Korean Hip Society; 6 - Manaster BJ. Adult Chronic Hip Pain: Radiographic Evaluation RadioGraphics; 7 - Marchiori DM. Clinical Imaging Elsevier Mosby; 8 - Moeller T. Normal Findings in Radiography Thieme; 9 - Polesello GC, et al. Proposal for standardization of radiographic studies on the hip and pelvis Rev Bras Ortop 46(6):634-42; 10 - Tönnis D. Normal values of the hip joint for the evaluation of X-rays in children and adults. Sep Clin Orthop Relat Res; Page 48 of 49

49 Personal Information Lead author: Dr Ana Luísa Proença, Radiology Resident at Centro Hospitalar Lisboa Central, Lisbon. A special thanks to radiographer António Dias and the model Maria Adelaide Sousa for the collaboration on this work. Page 49 of 49