Ultrasound of the Hip: Anatomy, Pathology, and Procedures

Transcription

1 Ultrasound of the Hip: Anatomy, Pathology, and Procedures Jon A. Jacobson, M.D. Professor of Radiology Director, Division of Musculoskeletal Radiology University of Michigan Outline Hip Joint Native hip Arthroplasty Greater Trochanter Tendon abnormalities Bursal pathology Snapping Hip Hip: anterior recess Anterior and posterior layers Fibrous tissue + minute layer of synovium Hyperechoic Each 2-4 mm thick Radiology 1999; 210:499 Hip: anterior recess Anterior Posterior Femur Hip Joint Hip Effusion: A H Separation of anterior and posterior layers 1 Capsule distention at femoral neck > 7 mm or difference of 1 mm from opposite side 2 Extension & abduction improves visualization 3 Do not internally rotate hip: capsule thickens Sagittal-oblique 1 Radiology 1999; 210:449 2 Scand J Rheumatology 1989; 18:113 3 Acta Radiologica 1997; 38:867 1

2 Hip Joint: septic effusion FH * * Long Axis * * Hip Effusion: misconception It is incorrect to assume that joint fluid may not be seen anterior due to gravity Native hip: joint fluid distributes around femoral neck In no cases was fluid only seen posterior Exception: after hip surgery Moss et al. Radiology 1998; 208:43 Hip Effusion: Cannot predict infection by ultrasound Negative power color Doppler does not exclude infection* Guided aspiration * AJR 1998; 206:731 * * Joint injection Anterior recess In plane Transducer: Parallel to femoral neck Consider curvilinear Needle: distal to proximal 97% accuracy 1 1 Smith J. J Ultrasound Med 2009; 28:329 F Joint Injection Femoral neck target Preferred over aiming for femoral head Allows higher injection volumes Less extra-articular contrast From Kantarci F et al. Skeletal Radiol 2013; 42:37. Joint injection Transducer: in plane Lateral to medial Horizontal and parallel to sound beam Courtesy of Mark Cresswell, Vancouver F H N N 2

3 Pigmented Villonodular Synovitis Juvenile Rheumatoid Arthritis Erosion Hip Labrum Normal: Hyperechoic, triangular Degeneration: hypoechoic Tear: anterior Anechoic cleft Sensitivity 82%, specificity 60%, accuracy 80%* Chondrocalcinosis Acetab Labral Tear Femoral Femoroacetabular Impingement Pincer-type: deep acetabulum Cam-type Broad irregular femoral neck Possible cortical irregularity at US Associated with anterior labrum tear Consider dynamic evaluation Detachment *Jin W et al. J Ultrasound Med 2012; 31:439 Radiology 2005; 236:588 Labral Tear and Paralabral Cyst Associated with labral tear Full-thickness or detachment Anechoic to hypoechoic Multilocular Hip Arthroplasty: Prosthesis identifiable May use sonography to guide hip aspiration Most useful: non-communicating abscess, bursitis, incision infection Courtesy of D. Fessell, Ann Arbor, MI 3

4 Total Hip Arthroplasty: Metal components demonstrate posterior reverberation Artifact occurs deep to prosthesis away from fluid collection (unlike MRI, CT) Acet H Femur Hip Arthroplasty: Ultrasound cannot differentiate small effusion from post-op change 1 Suspect infection: Pseudocapsule > 3.2 mm: suspect infection 2 Extra-articular fluid collection Not visualized with arthrography if noncommunication A > 3.2 mm 1 Weybright PN et al. AJR 2003; 181:215 2 AJR 1994; 163:381 Hip Arthroplasty: infection Hip Arthroplasty: infection Superior Inferior Femur Sagittal Native Femur Coronal Radiograph Teaching Point: Always screen soft tissues about an arthroplasty prior to fluoroscopic joint aspiration Metal-on-Metal Arthroplasty: pseudotumor Troch Cup Cup Iliopsoas Bursa Hip joint communication in 10% Increased with hip joint pathology After joint replacement May extend cephalad into abdomen May be mistaken for psoas abscess Look for hip joint communication Anterior Lateral Radiology 1995; 197:853 4

5 Iliopsoas Bursal Fluid Iliopsoas Bursa IP Oblique-axial plane: Superior to femoral head Lateral to medial Inject between tendon and ilium 1 Pain relief = successful iliopsoas surgical release 2 Femoral Axial T1w post-gadolinium 1 Dauffenbach J et al. J Ultrasound Med 2014; 33:405 2 Blankenbaker DG et al. Skeletal Radiol 2006; 35: 565 Ilium I Outline Greater Trochanter: gluteal tendons Anterior Lateral Posterior Hip Joint Native hip Arthroplasty Greater Trochanter Tendon abnormalities Bursal pathology Snapping Hip Gluteus medius (red) Gluteus minimus (blue) Greater Trochanter Greater Trochanter Subgluteus Medius Bursa Trochanteric Bursa TFL Gluteus Medius Gluteus Minimus Subgluteus Minimus Bursa Glut Max PF : anterior facet : lateral facet PF: posterior facet FACETS: = anterior; = lateral; SPF = superoposterior; PF = posterior Pfirrmann et al. Radiology 2001; 221:469 5

6 Gluteus Minimus and Medius: Long Axis Gluteus Minimus: Long Axis Gluteus Medius Gluteus Minimus Gmed Gmed PF Anterior Facet Gluteus Medius: Long Axis Iliotibial Tract Lateral Facet Trochanteric Pain Syndrome: Most commonly caused by gluteus minimus and medius tendon abnormalities 1 Trochanteric bursitis: uncommon 20% of symptomatic patients 2 Not actually inflamed 3 Not associated with pain 4 1 Kong A et al. Eur Rad 2007; 17: Long SS et al. AJR 2013; 201: Sylva F et al. Clin Rheumatol 2008; 14:82 4 Blankenbaker DG et al. Skeletal Radiol 2008; 37:903 Tendinosis: Gluteus Minimus Gluteal Tendon Pathology: Tendinosis: hypoechoic, no defects Partial tear: anechoic clefts Complete tear: discontinuous tendon >2 mm cortical irregularity (depth) Associated with tendon tear Positive predictive value = 90% (xray)* *Steinert et al. Radiology 2010; 257:754 6

7 Tear: Gluteus Minimus Tendinosis: Gluteus Medius SPF Tear: Gluteus Medius Tear: Gluteus Medius after THA SPF >2 mm cortical irregularity depth (x-ray) = 90% positive predictive value for gluteus tendon tear Steinert et al. Radiology 2010; 257:754 Post-operative: Gluteus Medius Calcific Tendinosis: Gluteus Medius SPF Long Axis Short Axis 7

8 Fenestration: pelvis 22 tendons in 21 patients Gluteus medius (11), hamstring (8), gluteus minimus (2), tensor fascia lata (1) Marked or some improvement: 82% Greater Trochanter Gluteus Medius Needle Jacobson JA et al. J Ultrasound Med 2015; 34:2029 Normal PRP and Tendon Injection Trochanteric Bursal Fluid + Glut Min Tear Gluteal Tendons: greater trochanter Randomized controlled: 30 patients PRP versus fenestration alone Significant improvement at weeks 1 and 2 Approximately 80% had long term improvement: up to 1 year follow-up No difference between treatment groups Glut Max PF Jacobson JA et al. J Ultrasound Med 2016; 35:2413 Axial Trochanteric Bursitis Trochanteric Bursa: infection + gas T1w Greater Trochanter 8

9 Trochanteric Region Bursae Outline Trochanteric: deep to gluteus maximus Subgluteus medius Subgluteus minimus Axial or coronal plane PF Hip Joint Native hip Arthroplasty Greater Trochanter Tendon abnormalities Bursal pathology Snapping Hip Iliopsoas Complex A Snapping Hip Syndrome AIIS Painful snap with hip motion Intraarticular Extraarticular: Anterior: iliopsoas tendon Lateral: iliotibial tract or gluteus maximus A B Ilium Red: psoas major Orange: medial iliacus fibers Purple: lateral iliacus fibers Femoral Pubis Short Axis From: Guillin R. et al. Eur Rad 2009; 19:995 Snapping Hip Syndrome: iliopsoas Snapping Hip Syndrome: iliopsoas Image long axis to inguinal ligament superior to femoral head Extension of flexed abducted and externally rotated hip Abrupt movement of iliopsoas as iliacus muscle interposed between tendon and bone moves Deslandes et al. AJR 2008; 190: Deslandes et al. AJR 2008; 190:576 9

10 Snapping Hip Syndrome: iliopsoas Snapping Hip: lateral Transverse over greater trochanter Hip external rotation / flexion Abrupt motion of iliotibial tract or gluteus maximus over greater trochanter Gluteus Maximus Snapping Gluteus Maximus / Iliotibial Band Gluteus Medius TFL Gluteus Maximus Iliotibial Band Gmin Snapping Hip Syndrome: iliotibial tract Iliotibial Band Gmax Gmed Gmin Take-home points: Hip: Native: focus on anterior recess Arthroplasty: pseudotumor, iliopsoas bursa Greater trochanter: Bursitis uncommon Tendinosis and tendon tear Snapping Hip: Iliopsoas and iliotibial tract/gluteus maximus See for syllabus and other educational material 10