Sonographic Evaluation of Snapping Hip Syndrome

3206jum1online.qxp:Layout 1 5/21/13 11:48 AM Page 895

SOUND JUDGMENT SERIES

Nathalie J. Bureau, MD, FRCPC

Invited paper

Videos online at www.jultrasoundmed.org napping hip syndrome is characterized by a painful, palpable, and sometimes audible snap caused during certain movements of the hip.1 Painless occasional snapping phenomena S 2–4 can occur in asymptomatic people. These episodes are considered The Sound Judgment Series consists of physiologic occurrences and should not be a cause for concern, nor invited articles highlighting the clinical should they be investigated. value of using ultrasound first in specific The pathophysiologic mechanisms of snapping hips are diverse, clinical diagnoses where ultrasound has and the exact cause of the painful anatomic conflict or snap may be difficult to identify with diagnostic tests. Although imaging tech- shown comparative or superior value. The niques such as radiography, computed tomography, and magnetic series is meant to serve as an educational resonance imaging (MRI) may yield useful and complementary tool for medical and sonography students information in these patients, sonography, with its high resolution and clinical practitioners and may help and dynamic capabilities, is the imaging modality of choice in the integrate ultrasound into clinical practice. investigation of snapping hip syndrome.5–8 Popularized at the turn of the 20th century, the term snapping hip referred to the snapping of the iliotibial band on the greater trochanter until Nunziata and Blumenfeld9 published a series of 3 patients with internal snapping hip involving the iliopsoas tendon Received January 24, 2013, from the Department 10 Radiology, University of Montreal Medical Cen- in 1951. In 1995, Allen and Cope proposed a classification for snap- ter, Montreal, Quebec, Canada. Revision requested ping hip syndrome that distinguished intra- and extra-articular causes. February 8, 2013. Revised manuscript accepted According to this classification, various lesions, such as synovial for publication March 27, 2013. chondromatosis, loose bodies, labral tears, synovial plicae, and Dr Bureau is a recipient of a Canadian chondral defects, may present with snapping or catching symptoms, Institutes of Health Research training grant for caused by movement of the hip joint. These symptoms are usually evaluation and treatment of mobility and posture disorders (MENTOR Program). of low intensity and differ considerably from the more powerful Address correspondence to Nathalie J. snapping typical of the extra-articular type. Consequently, it is prob- Bureau, MD, FRCPC, Department of Radiology, ably more appropriate to reserve the term snapping hip syndrome for University of Montreal Medical Center, 1058 the extra-articular causes.11 Saint-Denis St, Montreal, QC H2X 3J4, Canada. The extra-articular type of snapping hip syndrome comprises E-mail: [email protected] 3 categories (Table 1): internal, which involves the musculotendinous iliopsoas unit; external, which involves the iliotibial band and Abbreviations 10 MRI, magnetic resonance imaging the gluteus maximus muscle ; and posterior, which is less common and involves the ischiofemoral region.12–15 Sonographic evaluation doi:10.7863/ultra.32.6.895 of this last entity has not been reported to date.

Bureau—Sonographic Evaluation of Snapping Hip Syndrome

Internal Snapping Hip Syndrome The terms iliopsoas tendon and psoas major tendon have been used interchangeably in the medical literature. Internal snapping hip syndrome affects predominantly At the level of the superior pubic ramus, the tendon involved young adults, especially women, athletes, and, more specif- in the snapping mechanism is the psoas major. The accessory ically, ballet dancers. Activities requiring repeated hip tendon of the iliacus muscle and the psoas major tendon abduction movements, such as ballet dancing, martial arts, merge distally to the superior pubic ramus to form the and gymnastics, increase the risk. In a study involving 87 iliopsoas tendon.18 dancers from the National Ballet of Canada, 91% of the A painful snapping iliopsoas tendon can occur in dancers presented with snapping hip phenomena. In 80% patients with total hip arthroplasty. This infrequent compli- of the dancers, both hips were affected, and in 58% of cases, cation of total hip arthroplasty tends to become apparent painful symptoms were associated with the snapping hip.16 during the postoperative period. The most common cause The musculotendinous unit of the iliopsoas is most is overlap of the prosthetic cup at the anterior acetabular often involved in causing internal snapping hip syndrome. margin, over which the iliopsoas tendon extends as it leaves The anatomy of the iliopsoas is complex and important the pelvis.23,24 Other causes include lengthening and conse- to know to understand the physiologic characteristics and, quent tension on the iliopsoas tendon caused by a prosthetic secondarily, the pathophysiologic mechanisms of internal femoral neck that is too long, the presence of cement debris snapping hip syndrome.17 This anatomy has been recently in front of the acetabular cup, and acetabular cup screws or redefined by cadaver studies18 and detailed using MRI.19,20 bone grafts protruding from the acetabulum.25,26 Furthermore, using static and dynamic sonography, Guillin The sonographic examination of the internal hip com- et al2 documented the sonographic anatomy of the iliop- partment begins with a static evaluation in the longitudinal soas at the inguinal level and its physiologic motion during and transverse planes, using a multifrequency 5–12-MHz flexion-abduction-external rotation followed by extension linear array transducer with the patient lying supine (Fig- of the hip in 21 asymptomatic volunteers (Figure 1 and ure 1). In some patients with larger body habitus, the use Video 1). Interestingly, the authors found a snapping hip phenomenon in 40% of this asymptomatic sample. Table 1. Causes of Snapping Hip Syndrome The initially proposed pathophysiologic mechanism of Internal internal snapping hip was impingement of the iliopsoas ten- Psoas major tendon snapping on the superior pubic ramus after 1,3 don on the iliopectineal eminence or the lesser trochanter. release of the medial fibers of the iliacus muscle from a However, this presumed mechanism has never been transient position between the psoas major tendon and the shown by direct visualization of the anatomic structures superior pubic ramus on imaging, and it remains hypothetical. Sonography has Psoas major tendon impingement on an anterior paralabral cyst Conflict between the two components of a bifid psoas helped identify various pathophysiologic mechanisms major tendon 7,8,16,21 underlying internal snapping hip. The most fre- Psoas major tendon impingement on the anteroinferior iliac spine quently reported mechanism is snapping of the psoas Iliopsoas tendon impingement on a protruding acetabular major tendon on the superior pubic ramus after release of component of total hip arthroplasty Iliopsoas tendon impingement on the iliopectineal eminence the medial fibers of the iliacus muscle. During flexion- (to date, this presumed mechanism has not been shown by abduction-external rotation of the hip, the medial fibers of direct visualization on imaging) the iliacus muscle become confined between the psoas Friction of the iliofemoral ligament on the femoral head (to date, major tendon and the superior pubic ramus. On extension this presumed mechanism has not been shown by direct and adduction of the hip, the medial fibers of the iliacus visualization on imaging) External muscle suddenly free themselves from this position, which Friction or subluxation of the iliotibial band or gluteus maximus causes the psoas major tendon to return abruptly against the muscle on the greater trochanter superior pubic ramus, generating a painful snap (Video 2). Iliotibial band impingement on a femoral osteochondroma Other mechanisms that have been reported to cause Venous hemangioma of the gluteus maximus muscle painful snapping hip include the conflict between the two Posterior 7,22 Subluxation of the tendon of the long head of the biceps femoris components of a bifid psoas major tendon, snapping of muscle (to date, this mechanism has not been shown by direct the psoas major tendon at the level of the anteroinferior visualization on imaging) iliac spine while in the flexion-abduction-external rotation Ischiofemoral impingement with abnormalities of the quadratus (frog leg) position, and impingement of the psoas major femoris muscle (to date, this mechanism has not been shown tendon on a paralabral cyst.7 by direct visualization on imaging)

896 J Ultrasound Med 2013; 32:895–900 3206jum1online.qxp:Layout 1 5/21/13 11:48 AM Page 897

Bureau—Sonographic Evaluation of Snapping Hip Syndrome

of a 3–5-MHz curvilinear transducer may be indicated. to make a video recording of the dynamic study to be able Although infrequent in the presence of internal snapping to review the images more closely. hip syndrome, anomalies such as iliopsoas tendinopathy, The investigation of the painful hip should begin with bursitis, coxofemoral synovitis, and a paralabral cyst are radiographs of the pelvis and hip to exclude congenital, systematically sought.4,7,8,27 During the dynamic evalua- traumatic, or neoplastic osseous lesions as well as inflam- tion, the transducer is applied firmly and maintained in an matory, degenerative, or dysplastic joint disease. A sono- oblique transverse plane between the anteroinferior iliac graphic examination should be performed if a snapping spine and the superior pubic ramus. The movement of the phenomenon is present. Because sonography is not psoas major tendon and iliacus muscle is observed on real- degraded by metallic artifacts, it is especially useful in time sonography while the patient executes a motion of patients with total hip arthroplasty to evaluate the iliopsoas flexion-abduction-external rotation, followed by extension tendon.28 Computed tomography can also be useful in and adduction of the hip. In most cases, this motion will investigating patients with total hip arthroplasty to show elicit the snapping, but patients may also be asked to per- the relationship between the prosthesis, the bone struc- form any other movements that they know will reproduce tures, and the iliopsoas tendon.29 Other causes of painful the snapping symptoms. Given that the movements of hip, including synovial chondromatosis, loose bodies, structures are usually rapid and complex, it is often useful labral tears, synovial plicae, chondral defects, transient

Figure 1. Dynamic sonographic examination of internal snapping hip syndrome. A, The patient is supine. The probe is placed in a transverse oblique plane between the anteroinferior iliac spine and the superior pubic ramus to examine the iliopsoas musculotendinous complex in real time while the patient executes a motion of flexion-abduction-external rotation of the hip, followed by extension and adduction. B, Transverse oblique sonogram at the level of the superior pubic ramus (SPR) with the hip in extension-adduction (neutral position) showing the psoas major tendon (PT) and muscle (asterisk), the medial fibers of the iliacus muscle (MFI), the lateral fibers of the iliacus muscle (LFI), and the accessory tendon (arrow), which originates from the medial fibers of the iliacus muscle. C, Transverse oblique sonogram, slightly more lateral than B, centered on the anteroinferior iliac spine (AIIS) while the hip is in flexion-abduction-external rotation. D, Transverse oblique sonogram at the level of the superior pubic ramus showing the components of the iliopsoas musculotendinous complex coming back toward their resting position while the hip is brought back in the extension-adduction position. A B

C D

J Ultrasound Med 2013; 32:895–900 897 3206jum1online.qxp:Layout 1 5/21/13 11:48 AM Page 898

Bureau—Sonographic Evaluation of Snapping Hip Syndrome

subluxation of the femoral head, and femoroacetabular This entity, described by Mayer38 in 1919, is usually impingement, will be more appropriately evaluated with diagnosed clinically. Young adults, especially athletes, are conventional MRI or MR arthrography.30,31 at increased risk.10 Dynamic sonography can show the Initially, treatment of internal snapping hip syndrome abrupt abnormal movement of the structures causing the is conservative and may include rest from sporting activities, painful snapping in these patients. The sonographic eval- stretching exercises, and nonsteroidal anti-inflammatory uation of the external compartment of the hip is performed drugs. Sonographically guided corticosteroid injections in with the patient in the lateral decubitus position, lying on the iliopsoas bursa may be beneficial.32,33 In cases refractory the asymptomatic side (Figure 2). The static evaluation of to conservative treatment, arthroscopic iliopsoas tendon the muscular and tendinous structures and peritrochanteric release has been shown to be effective.34,35 bursas is conducted with a multifrequency 5–12-MHz linear array probe in the longitudinal and transverse planes. External Snapping Hip Syndrome In the presence of painful snapping, a thickened and hypoechoic iliotibial band6 and a thickened and inflamed External snapping hip syndrome is caused by an abnor- greater trochanteric bursa,39 can be detected. During hip mal “jerky” movement or transient subluxation of the flexion and extension, the iliotibial band and anterior mar- junction between the iliotibial band and the anterior margin of the gluteus maximus muscle glide gently, anteriorly gin of the gluteus maximus muscle over the greater (during flexion) and posteriorly (during extension), over trochanter.6 This condition usually occurs with no appar- the lateral facet of the greater trochanter. In the presence of ent extrinsic cause, although external snapping hip has external snapping, during the early phase of flexion, the been reported in the presence of a femoral osteochon- iliotibial band and gluteus maximus are restrained tran- droma36 and a venous malformation of the gluteus max- siently against the posterolateral aspect of the greater imus muscle.37 trochanter. As the degree of flexion increases, the iliotibial

A Figure 2. Dynamic sonographic examination of external snapping hip syndrome. A, The patient is in the lateral decubitus position. The probe is placed in a transverse position on the greater trochanter to examine the movement of the anterior margin of the gluteus maximus muscle and the iliotibial band over the lateral facet of the greater trochanter in real time while the patient executes motions of flexion and extension of the hip. B, Transverse sonogram at the level of the greater trochanter during hip flexion showing the anterior margin (long arrow) of the gluteus maximus muscle (GM) and the iliotibial band (short arrow) moving anteriorly over the gluteus medius tendon (single asterisk), which inserts on the lateral facet (LF) of the greater trochanter. The gluteus minimus tendon (double aster- isks) inserts on the anterior facet (AF) of the greater trochanter. C, Trans- verse sonogram at the level of the greater trochanter during hip extension. The gluteus maximus muscle (long arrow) and the iliotibial band (short arrow) move posteriorly relative to the lateral facet of the greater trochanter. B C

898 J Ultrasound Med 2013; 32:895–900 3206jum1online.qxp:Layout 1 5/21/13 11:48 AM Page 899

Bureau—Sonographic Evaluation of Snapping Hip Syndrome

band and gluteus maximus are suddenly released, moving 6. Choi YS, Lee SM, Song BY, Paik SH, Yoon YK. Dynamic sonography of forward abruptly over the anterior edge of the lateral facet external snapping hip syndrome. J Ultrasound Med 2002; 21:753–758. of the greater trochanter while generating the snapping 7. Deslandes M, Guillin R, Cardinal E, Hobden R, Bureau NJ. The snap- (Video 3). These patients may sometimes need to be ping iliopsoas tendon: new mechanisms using dynamic sonography. AJR examined while standing and leaning on the symptomatic Am J Roentgenol 2008; 190:576–581. side to provoke the snapping. In this position, the sympto- 8. Janzen DL, Partridge E, Logan PM, Connell DG, Duncan CP. The snap- matic hip is in adduction, and the iliotibial band is pressed ping hip: clinical and imaging findings in transient subluxation of the iliop- firmly against the posterolateral aspect of the greater soas tendon. Can Assoc Radiol J 1996; 47:202–208. trochanter. As the hip flexes, the iliotibial band tightens and 9. Nunziata A, Blumenfeld I. Cadeva a resorte: a proposito de una variedad. then abruptly completes an anterior translation, causing Prensa Med Argent 1951; 38:1997–2001. the snapping. Snapping may also occur during hip exten- 10. Allen WC, Cope R. Coxa saltans: the snapping hip revisited. J Am Acad sion while the iliotibial band and the anterior margin of Orthop Surg 1995; 3:303–308. the gluteus maximus muscle are moving posteriorly over 11. Byrd JW. Evaluation and management of the snapping iliopsoas tendon. the greater trochanter. Instr Course Lect 2006; 55:347–355. Conservative management, including rest, stretching 12. Ali AM, Whitwell D, Ostlere SJ. Case report: imaging and surgical treat- exercises, and nonsteroidal anti-inflammatory drugs, is ment of a snapping hip due to ischiofemoral impingement. Skeletal Radiol considered the mainstay for the treatment of lateral snap- 2011; 40:653–656. ping hip syndrome. Sonographically guided corticos- 13. Patti JW, Ouellette H, Bredella MA, Torriani M. Impingement of lesser teroid injections in the greater trochanteric bursa may be trochanter on ischium as a potential cause for hip pain. Skeletal Radiol beneficial. Surgery is considered for patients refractory to 2008; 37:939–941. this regimen. Various surgical techniques for iliotibial 14. Rask MR. “Snapping bottom”: subluxation of the tendon of the long head band plasty and fibrous band release of the gluteus max- of the biceps femoris muscle. Muscle Nerve 1980; 3:250–251. imus muscle are used and generally provide good clinical 15. Torriani M, Souto SC, Thomas BJ, Ouellette H, Bredella MA. results.39,40 Ischiofemoral impingement syndrome: an entity with hip pain and abnormalities of the quadratus femoris muscle. AJR Am J Roentgenol 2009; Conclusions 193:186–190. 16. Winston P, Awan R, Cassidy JD, Bleakney RK. Clinical examination and Snapping hip symptoms must be investigated when they ultrasound of self-reported snapping hip syndrome in elite ballet dancers. cause discomfort or pain. Combined with radiography of the Am J Sports Med 2007; 35:118–126. pelvis and hip, dynamic sonography is the imaging modality 17. Testut L. Ostéologie, arthrologie, myologie. In: Traité d’Anatomie Humaine. of choice in this clinical setting, allowing correlation of the Vol 1. Paris, France: Doin; 1921:855–859. snapping phenomenon with the abnormal movement of an 18. Tatu L, Parratte B, Vuillier F, Diop M, Monnier G. Descriptive anatomy underlying structure and the patient’s symptoms. The of the femoral portion of the iliopsoas muscle: anatomical basis of anterior differential diagnosis of snapping hip syndrome includes snapping of the hip. Surg Radiol Anat 2001; 23:371–374. intra-articular lesions, which are more appropriately investi- 19. Alpert JM, Kozanek M, Li G, Kelly BT, Asnis PD. Cross-sectional analy- gated with MRI or computed tomography. sis of the iliopsoas tendon and its relationship to the acetabular labrum: an anatomic study. Am J Sports Med 2009; 37:1594–1598. References 20. Polster JM, Elgabaly M, Lee H, Klika A, Drake R, Barsoum W. MRI and gross anatomy of the iliopsoas tendon complex. Skeletal Radiol 2008; 37:55–58. 1. Schaberg JE, Harper MC, Allen WC. The snapping hip syndrome. Am J 21. Hashimoto BE, Green TM, Wiitala L. Ultrasonographic diagnosis of hip Sports Med 1984; 12:361–365. snapping related to iliopsoas tendon. J Ultrasound Med 1997; 16:433– 2. Guillin R, Cardinal E, Bureau NJ. Sonographic anatomy and dynamic 435. study of the normal iliopsoas musculotendinous junction. Eur Radiol 22. Shu B, Safran MR. Case report: bifid iliopsoas tendon causing refractory 2009; 19:995–1001. internal snapping hip. Clin Orthop Relat Res 2011; 469:289–293. 3. Lyons JC, Peterson LF. The snapping iliopsoas tendon. Mayo Clin Proc 23. Brew CJ, Stockley I, Grainger AJ, Stone MH. Iliopsoas tendonitis caused 1984; 59:327–329. by overhang of a collared femoral prosthesis. J Arthroplasty 2011; 4. Pelsser V, Cardinal E, Hobden R, Aubin B, Lafortune M. Extraarticular snap- 26:504.e17–504.e19. ping hip: sonographic findings. AJR Am J Roentgenol 2001; 176:67–73. 24. Vandenbussche E, Saffarini M, Taillieu F, Mutschler C. The asymmetric 5. Cardinal E, Buckwalter KA, Capello WN, Duval N. US of the snapping profile of the acetabulum. Clin Orthop Relat Res 2008; 466:417–423. iliopsoas tendon. Radiology 1996; 198:521–522.

J Ultrasound Med 2013; 32:895–900 899 3206jum1online.qxp:Layout 1 5/21/13 11:48 AM Page 900

Bureau—Sonographic Evaluation of Snapping Hip Syndrome

25. Bricteux S, Beguin L, Fessy MH. Iliopsoas impingement in 12 patients with a total hip arthroplasty [in French]. Rev Chir Orthop Reparatrice Appar Mot 2001; 87:820–825. 26. Lequesne M, Dang N, Montagne P, Lemoine A, Witvoet J. Conflict between psoas and total hip prosthesis [in French]. Rev Rhum Mal Osteoar- tic 1991; 58:559–564. 27. Jacobson T, Allen WC. Surgical correction of the snapping iliopsoas tendon. Am J Sports Med 1990; 18:470–474. 28. Rezig R, Copercini M, Montet X, Martinoli C, Bianchi S. Ultrasound diagnosis of anterior iliopsoas impingement in total hip replacement. Skeletal Radiol 2004; 33:112–116. 29. Cyteval C, Sarrabère MP, Cottin A, et al. Iliopsoas impingement on the acetabular component: radiologic and computed tomography findings of a rare hip prosthesis complication in eight cases. J Comput Assist Tomogr 2003; 27:183–188. 30. Blankenbaker DG, Tuite MJ. The painful hip: new concepts. Skeletal Radiol 2006; 35:352–370. 31. Katz LD, Haims A, Medvecky M, McCallum J. Symptomatic hip plica: MR arthrographic and arthroscopic correlation. Skeletal Radiol 2010; 39:1255–1258. 32. Adler RS, Buly R, Ambrose R, Sculco T. Diagnostic and therapeutic use of sonography-guided iliopsoas peritendinous injections. AJR Am J Roentgenol 2005; 185:940–943. 33. Blankenbaker DG, De Smet AA, Keene JS. Sonography of the iliopsoas tendon and injection of the iliopsoas bursa for diagnosis and management of the painful snapping hip. Skeletal Radiol 2006; 35:565–571. 34. Anderson SA, Keene JS. Results of arthroscopic iliopsoas tendon release in competitive and recreational athletes. Am J Sports Med 2008; 36:2363– 2371. 35. Flanum ME, Keene JS, Blankenbaker DG, De Smet AA. Arthroscopic treatment of the painful “internal” snapping hip: results of a new endoscopic technique and imaging protocol. Am J Sports Med 2007; 35:770– 779. 36. Inoue S, Noguchi Y, Mae T, Rikimaru S, Hotokezaka S. An external snapping hip caused by osteochondroma of the proximal femur. Mod Rheuma- tol 2005; 15:432–434. 37. Lin CL, Huang MT, Lin CJ. Snapping hip caused by a venous hemangioma of the gluteus maximus muscle: a case report. J Med Case Rep 2008; 2:386. 38. Mayer L. Snapping hip. Surg Gynecol Obstet 1919; 29:425–428. 39. Yoon TR, Park KS, Diwanji SR, Seo CY, Seon JK. Clinical results of mul- tiple fibrous band release for the external snapping hip. J Orthop Sci2009; 14:405–409. 40. Ilizaliturri VM Jr, Martinez-Escalante FA, Chaidez PA, Camacho-Galindo J. Endoscopic iliotibial band release for external snapping hip syndrome. Arthroscopy 2006; 22:505–510.

900 J Ultrasound Med 2013; 32:895–900