Hip Ultrasound Disclosures • Consultant: Bioclinica Jon A. Jacobson, MD • Contractor: POCUS PRO • Advisory Board: Philips FACR, FAIUM, FSRU, RMSK • Book Royalties: Elsevier Professor of Radiology • Not relevant to this lecture Director, Division of Musculoskeletal Radiology Note: all images from the textbook University of Michigan Fundamentals of Musculoskeletal Ultrasound are copyrighted by Elsevier Inc. See www.jacobsonmskus.com for syllabus other educational material Sonographic Technique: hip and thigh Outline: • Anterior: • Sonographic technique – Hip joint • Normal anatomy – Anterior hip muscles, iliopsoas bursa • Common pathology – Consider: symphysis pubis, inguinal hernia • Lateral: gluteal tendons, bursae • Medial: adductors • Posterior: hamstring Hip: anterior recess Sonographic Technique: Hip • Anterior and posterior layers • Anterior – Hip joint – Fibrous tissue + minute layer of synovium – Anterior musculature – Hyperechoic Radiology – Snapping iliopsoas – Each 2 - 4 mm thick 1999; 210:499 – Iliopsoas bursa – Lateral femoral cutaneous nerve • Transducers: – 10 – 12 MHz linear – <10 MHz curvilinear if needed 1 Hip: anterior recess Hip Joint Anterior Posterior Femur Femur Transverse Iliopsoas Lateral Femoral Inguinal Ligament A Complex Cutaneous Nerve AIIS • Sensory: anterolateral thigh • Variable course: Anterior Superior A Ilium – 62% medial, 27% superficial, Iliac Spine B 11% lateral to ASIS • Variable branching • Superficial to sartorius Sartorius – Lateral TFL Iliacus fat triangle Pubis Femoral Rudin D et al. Head From: Guillin R. et al. Eur Rad Short Axis JBJS 2016; 2009; 19:995 98:561 Distal Greater Trochanter: gluteal tendons Sonographic Technique: Hip Lateral Anterior Posterior • Lateral – Greater trochanter – Gluteal tendons – Bursae – Snapping hip • Transducers: – 10 – 12 MHz linear – <10 MHz curvilinear if needed Gluteus medius (red) Gluteus minimus (blue) 2 Greater Trochanter Greater Trochanter Yellow arrow = gluteus medius Inferior 12 White arrow = gluteus minimus Axial MRI FACETS: AF = anterior; LF = lateral; SPF = superoposterior; PF = posterior 3 Superior 4 Pfirrmann et al. Radiology 2001; 221:469 Greater Trochanter Greater Trochanter Subgluteus Medius Gluteus Medius Gluteus Bursa Minimus TFL Trochanteric Bursa Glut Subgluteus Max Minimus Bursa LF AF PF AF: anterior facet Anterior Posterior LF: lateral facet PF: posterior facet Yellow arrow = gluteus medius White arrow = gluteus minimus Gluteus Minimus and Medius: Long Axis Gluteus Minimus: Long Axis Gluteus Gluteus Medius Minimus Gmed Gmed AF PF Anterior Facet 3 Gluteus Medius: Long Axis Sonographic Technique: Thigh Iliotibial • Posterior: Tract – Semimembranosus – Semitendinosus LF – Biceps femoris • Long and short heads Lateral – Sciatic nerve Facet • Transducers: – 10 – 12 MHz linear – <10 MHz curvilinear if needed Proximal Hamstring: gluteal fold Proximal Hamstring: gluteal fold to ischial tuberosity 1 2 3 Conjoined Medial Tendon ST ST BF Gluteal fold Moving proximal SM 4 Note: Long Axis Semimembranosus Adductor tendon (yellow Sciatic Magnus Nerve arrow) moving Transverse medial to lateral Note: Conjoined semitendinosus (ST) and biceps femoris long head (BF) tendon (yellow arrow), semimembranosus (SM blue arrow), and sciatic nerve in a triangle configuration *Conjoined ST-BF and SM tendons Ischial tuberosity only seen together in long axis when *Toggle transducer to eliminate anisotropy* they cross over distal to tuberosity Posterior Thigh: A Conjoined ST-BF Proximal hamstring: at ischial tuberosity Tendon proximal hamstring Conjoined ST-BF Tendon A SM Ischium Sciatic Nerve B B Semimembranosus SM Sacrotuberous Ischium Ligament Ischium Lateral Medial Ischium Transverse Lateral Medial Transverse 4 Posterior Thigh: longitudinal Pathology: • Joint abnormalities • Bursal pathology • Muscle and tendon injury • Snapping hip syndrome • Miscellaneous pathology Sciatic Nerve Hamstring Origin Hip Joint: septic effusion Hip Effusion: • Separation of anterior and posterior layers1 • Capsule distention at femoral neck > 7 mm or difference of 1 mm from opposite side2 • Extension & abduction improves * visualization3 FH * • Do not internally rotate hip: capsule thickens Neck * 1Radiology 1999; 210:449 * 2Scand J Rheumatology 1989; 18:113 Long Axis 3Acta Radiologica 1997; 38:867 Hip Joint: aseptic effusion Hip Effusion: misconception • It is incorrect to assume that joint fluid may not be seen anterior due to gravity FH • Native hip: joint fluid distributes around * femoral neck Acet • In no cases was fluid only seen posterior FH * • Exception: after hip surgery Neck Moss et al. Radiology 1998; 208:43 Sagittal 5 Hip Joint: aseptic effusion Pitfall: capsule thickening • Internal rotation of hip: – Anterior hip capsule – Thicker, convex anterior Neck Femoral Neck Axial External Rotation Internal Rotation Pigmented Villonodular Hip Effusion: Synovitis • Cannot predict infection by ultrasound • Negative power color * Doppler does not exclude infection* Head * • Guided aspiration Head Neck Erosion * AJR 1998; 206:731 Juvenile Idiopathic Arthritis Hip Labrum Labral Tear • Normal: – Hyperechoic, triangular • Degeneration: hypoechoic Acetab • Tear: anterior Femoral – Anechoic cleft Head – Sensitivity 82%, specificity Head 60%, accuracy 80%* Chondrocalcinosis Detachment *Jin W et al. J Ultrasound Med 2012; 31:439 6 Labral Tear and Paralabral Cyst Femoroacetabular Impingement • Associated with labral tear • Pincer-type: deep acetabulum – Full-thickness or detachment • Cam-type • Anechoic to hypoechoic – Broad irregular femoral neck • Multilocular – Possible cortical irregularity at US • Associated with anterior labrum tear • Consider dynamic evaluation Radiology 2005; 236:588 Courtesy of D. Fessell, Ann Arbor, MI Total Hip Hip Arthroplasty: Arthroplasty: • Ultrasound cannot differentiate small effusion • Metal components from post-op change1 demonstrate posterior • Suspect infection: reverberation A Acet Femur – Pseudocapsule > 3.2 mm: 2 • Artifact occurs deep to H Neck suspect infection prosthesis away from > 3.2 – Extra-articular fluid Head mm fluid collection (unlike collection MRI, CT) – Not visualized with Neck arthrography if non- communication 1Weybright PN et al. AJR 2003; 181:215 2AJR 1994; 163:381 Hip Arthroplasty: infection Hip Arthroplasty: infection Superior Inferior Femur Native Coronal Radiograph Femur Teaching Point: Always screen soft tissues about an arthroplasty Sagittal prior to fluoroscopic joint aspiration 7 Metal-on-Metal Arthroplasty: pseudotumor Pathology: • Joint abnormalities Troch • Bursal pathology Cup • Muscle and tendon injury Neck Cup • Snapping hip syndrome • Miscellaneous pathology Anterior Lateral Trochanteric Pain Syndrome: Trochanteric Bursal Fluid + Glut Min Tear • Most commonly caused by gluteus minimus and medius tendon abnormalities1 • Trochanteric bursitis: uncommon Posterior Anterior – 20% of symptomatic patients2 LF AF Glut 3 – Not actually inflamed Max PF – Not associated with pain4 1Eur Rad 2007; 17:1772 2Long SS et al. AJR 2013; 201:1083 3Clin Rheumatol 2008; 14:82 4Skeletal Radiol 2008; 37:903 Axial Trochanteric Bursitis: Septic Trochanteric Bursitis Gmax Note posterior location of bursa PF Gmax 8 Trochanteric Bursa: infection + gas 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 T1w – Look for hip joint communication Greater Trochanter Radiology 1995; 197:853 Iliopsoas Bursal Fluid Ischial or ischiogluteal Bursa • Uncommon • “Weaver’s Bottom” • Between ischial tuberosity and gluteus maximus IP Femoral Head Axial T1w post-gadolinium Pathology: Muscle and Tendon Injury • Joint abnormalities • Tear: – Anechoic or hypoechoic defect • Bursal pathology – Partial-thickness tear • Muscle and tendon injury – Full-thickness tear: retraction • Snapping hip syndrome • Tendinosis: • Miscellaneous pathology – Hypoechoic, enlarged – No inflammation (not tendinitis) 9 Tendinosis: Gluteus Medius Tendinosis: Gluteus Minimus AF LF AF LF SPF LF AF Calcific Tendinosis: Gluteus Medius Tear: Gluteus Medius after THA LF LF LF AF SPF LF LF AF AF Tear: Gluteus Minimus Semimembranosus: tendinosis Conjoint Conjoint Tendon Tendon AF LF Ischium AF SM >2 mm cortical irregularity depth (x-ray) = 90% positive predictive value for gluteus Long Axis Short Axis tendon tear Steinert et al. Radiology 2010; 257:754 10 Conjoined Biceps Femoris- Conjoined BF-ST Tendon: partial tear Semitendinosus: tendinosis Sacrotuberous Ligament Conjoined BF-ST Tendon Conjoined BF-ST tendon Ischial Tuberosity Ischium Semimembranosus Short Axis Long Axis Semimembranosus From: Bierry et al. Radiology 2014; 271:162 Snapping Conjoined Long Head Biceps Femoris, Semitendinosus Semimembranosus Tear + Sacrotuberous Ligament Conjoint Conjoint Tendon Tendon Sacrotuberous ST Ligament ST BF-ST BF SM Sciatic Ischium SM Nerve Tear Normal From Bierry G et al. Radiology Spencer-Gardner LS et al. PMR 2015; 7:1102 2014;271:162 Hamstring: complete tear with retraction Sports Hernia?: • A non-anatomic, non-diagnostic term attributed to many cause of groin pain – Tears or attenuation of inguinal structures – Bulge posterior wall of inguinal canal Ischium – Obturator nerve entrapment – Common aponeurosis abnormality: • Rectus abdominis and adductors tendons Long Axis – Associated: pubic symphyseal instability, FAI Omar IM et al. Radiographics 2008; 28:1415 Garvey JFW et al. Hernia 2010; 14:17 Hopkins JN et al. JBJS Reviews 2017; 5:1 11 Rectus Abdominis + Adductor: