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The hip abductors at MR imaging
European Journal of Radiology 81 (2012) 3755–3762
Contents lists available at ScienceDirect
European Journal of Radiology journal homepage: www.elsevier.com/locate/ejrad
Review
The hip abductors at MR imaging A. Hoffmann ∗ , C.W.A. Pfirrmann 1 Department of Radiology, University Hospital Balgrist, Forchstrasse 340, CH-8008 Zürich, Switzerland
a r t i c l e
i n f o
Article history: Received 7 January 2010 Received in revised form 1 March 2010 Accepted 4 March 2010 Keywords: MRI Hip Tendon tear Greater trochanter pain syndrome
a b s t r a c t Imaging of the hip abductors plays an increasing role for the evaluation of greater trochanteric pain in patients with and without total hip arthroplasty. This review article addresses the anatomy of the hip abductors and their intervening bursae. It highlights different possible imaging appearances such as tendinopathy or partial and full thickness tears of the gluteal tendons. Muscle atrophy or fatty degeneration of the gluteal muscles is an important reason for limping. Inflammatory diseases such as hydroxyapatite crystal deposition disease or spondylarthritis have to be considered. Knowledge of these different entities is important to achieve optimal treatment and outcomes. © 2010 Elsevier Ireland Ltd. All rights reserved.
1. Introduction
2. Anatomy
Orthopedic surgeons and rheumatologists show an increasing interest in imaging of the greater trochanter and abductors tendons. Greater trochanteric pain syndrom (GTPS) is a clinical term characterized by chronic pain and tenderness over the lateral aspect of the hip. Exacerbation of pain while lying on the affected side or while climbing stairs is typical. GTPS may have several differential diagnoses. The clinical term trochanteric bursitis suggested that bursitis is the only reason for the pain. However, in addition to primary bursitis, a fluid filled bursa may be secondary to disorders of abductor tendons of the hip. Magnetic resonance imaging (MRI) has shown that patients with GTPS often present with tendinopathy or tears of the abductor tendons. Tears of the abductor tendons have also been termed “rotator cuff tears of the hip” [1]. Imaging of the greater trochanter and the abductors tendons in patients after total hip arthroplasty (THA) suffering from trochanteric pain and limping is of increasing interest for hip surgeons. Detailed knowledge of the anatomy and the typical abnormal findings of the hip abductors and their intervening bursae are necessary to assess the reasons for GTPS or pain after THA and to initiate an effective treatment.
The greater trochanter has four distinct osseous facets that serve as specific tendon attachments and sites for bursae [2]. The anterior facet, best seen on axial images, serves as attachment of the gluteus minimus tendon (Fig. 1). The superoposterior facet, best seen on sagittal or coronal images, is covered by the main tendon of the gluteus medius muscle (Fig. 2). The lateral facet, best seen in coronal plane, is in contact with the superoposterior facet and is covered by the lateral part of the gluteus medius tendon (Fig. 3). There is no tendon attachment to the posterior facet, which is covered by the trochanteric bursa (TrB) (Fig. 4). The attachment of the gluteus medius tendon has three different parts (posterior, lateral, anterior part). The posterior part is the strong main tendon of the gluteus medius covering the superoposterior facet. The posterior part arises from the central posterior portion of the gluteus medius muscle and shows a coronal oblique orientation. The lateral part of the gluteus medius, covering the lateral facet, arises from the undersurface of the gluteus medius muscle and attaches to lower part of the lateral facet. The anterior part of the gluteus medius is usually a muscular attachment and attaches interiorly onto the tendon of the gluteus minimus tendon. The attachment of the gluteus minimus tendon can be divided into two components (Lateral, medial part). The lateral part of the gluteus minimus tendon consists of the main tendon, covering the lateral aspect of the anterior facet, and arises from the superficial part of the muscle fascia. The medial part of the gluteus minimus tendon shows a muscular insertion in the anterior and superior capsule of the hip joint. Bursae around the greater trochanter are very variable and tend to be more frequent in older individuals. Three bursae are consistently present in most individuals. The Trochanteric
∗ Corresponding author. Tel.: +41 44 386 1111; fax: +41 44 386 3309. E-mail addresses: [email protected] (A. Hoffmann), christian.pfi[email protected] (C.W.A. Pfirrmann). 1 Tel.: +41 44 386 1111; fax: +41 44 386 3309. 0720-048X/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrad.2010.03.002
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Fig. 1. Coronal T1-weighted MR image showing the normal gluteus minimus tendon (arrows) inserting at the anterior facet of the greater trochanter.
bursa (TrB) is the largest bursa, covering the posterior facet of the greater trochanter. The subgluteus medius bursa (SGMeB) is located between the superior part of the lateral facet and the lateral part of the gluteus medius tendon (Fig. 5). The subgluteus minimus bursa (SGMiB) lies beneath the gluteus minimus tendon, medial and superior to its insertion. In contrast to the SGMeB and the SGMiB the normal TrB can sometimes be detected on axial images, because it is surrounded by fat on both sides. Some authors use the term subgluteus maximus bursa synonymously with the TrB.
Fig. 3. Coronal T1-weighted MR image in a patient with a normal gluteus medius tendon. The lateral part of the gluteus medius tendon (arrow) inserts at the lateral facet of the greater trochanter. The open arrowhead points to the trochanteric bald spot.
3. Abnormal findings One of the possible reasons for GTPS is an abnormality of the gluteus medius or gluteus minimus tendon [3,4]. Several studies
Fig. 2. (a) Coronal and (b) sagittal T1-weighted MR image. The main part of the gluteus medius tendon (arrow) inserts at the superoposterior facet of the greater trochanter. On the sagittal image the insertion of the gluteus minimus tendon (arrowhead) at the anterior facet and the insertion of the main part of the gluteus medius tendon (arrow) at the superoposterior facet can be seen.
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Fig. 4. Axial T2-weighted fat-saturated MR image in a patient with trochanteric bursitis. The fluid-filled trochanteric bursa (arrow) covers the posterior facet of the greater trochanter.
could show that tendinopathy of the abductor tendons is significantly associated with lateral hip pain. Tendinopathy is usually characterized by increased signal of the tendon on T1w images (Fig. 6), while the fluid sensitive image is largely normal. A partial thickness tear is diagnosed by increased signal intensity on fluid sensitive images (Fig. 7). A full thickness tear consists of discontinuity of the tendon (Figs. 5 and 8). Blankenbaker et al. [5] showed that high signal intensity around the abductor tendon as well as bursal fluid and peritrochanteric edema can also be found in asymptomatic patients. In up to 22% patients undergoing surgery for femoral neck fractures, tears of the gluteus medius and gluteus minimus tendons were found [1]. Typical patients with tears of the abductor tendons are elderly women. Lequesne et al.
Fig. 5. Coronal T2-weighted fat-saturated MR image in a 68-year-old patient with left trochanteric pain. Full thickness tear of the lateral part of the gluteus medius tendon (arrowheads) and a fluid filled subgluteus medius bursa (arrows) are shown.
[6] compared MRI and surgical findings in patients with refractory GTPS. In this prospective study tears of the lateral part of the gluteus medius tendon were confirmed at surgery. Isolated tears of the gluteus minimus tendon were not seen. In this study tears were never located at the myotendinous junction. Correlation between MRI and surgery was also done by Chung et al. [7]. For three patients surgery revealed findings that corresponded with those of MRI. Gluteus medius tendon tears seem to be more frequent compared to gluteus minimus tendon tears [3,8] and most of them appear at the anterior portion at the lateral facet of the
Fig. 6. (a) Sagittal T1-weighted MR image showing a tendinopathy of the gluteus minimus (thin arrow) and the gluteus medius (thick arrow) tendon. Note the detachment of an ossicle (arrowhead) from the greater trochanter. (b) Coronal T2-weighted MR image in an 84-year-old woman with GTPS after THA demonstrating an osseous (arrowhead) detachment of the medius tendon (black arrow). The filled star marks the femoral component of the THA.
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Fig. 7. Coronal intermediate-weighted fat saturated MR image of a 67-year-old woman with refractory lateral hip pain. Note the partial tear of the gluteus minimus tendon (arrowheads) with increased signal and thickening of the tendon. Gluteus minimus muscle (star).
trochanter [4]. Cvitanic and coworkers could show in a study based on surgical findings of 21 consecutive patients, that gluteus medius and gluteus minimus tendons are torn with similar frequency [9]. Women are four times more frequently affected compared to men [1,10]. To avoid overestimation of the tendon detachment it is essential to be aware of an area devoid of a tendon attachment on the lateral facet of the trochanter (Fig. 3). This area is situated between the attachment of the gluteus medius tendon and the capsular portion of the gluteus minimus tendon. It is referred to as the trochanteric bald spot and gluteus medius tendon tear of each of its attachment sites has been described as producing a “bald trochanter” [11]. Addressing muscle atrophy or fatty degeneration of the abductor muscles are as important as assessing the integrity of the abductor tendons. Studies on the results of surgical repair of rotator cuff tears of the shoulder have shown that one of the preoperative factors associated with a less favorable result is poor muscle quality [12,13]. Atrophy and fatty degeneration of the abductor muscles may be graded using a classification system originally developed for the rotator cuff muscles of the shoulder [14] using transverse T1-weighted or T2-weighted non-fat saturated images. In Grad 0
Fig. 8. (a) Coronal T2-weighted non fat saturated and (b) axial intermediate-weighted fat saturated MR image in a 60-year-old woman with GTPS. A full detachment of the conjoined aponeurosis (arrowhead) between the gluteus medius tendon (muscle marked with full star) and the vastus lateralis (muscle marked with open star) from the greater trochanter can be seen.
Fig. 9. Axial T1-weighted MR images. (a) Normal anatomy of the gluteus minimus (A), gluteus medius (B) and gluteus maximus (C) muscles without atrophy or fatty degeneration. (b) Fatty degeneration Grad 4 of the gluteus minimus muscle (A) and Grad 2 of the gluteus medius (B) and maximus (C) muscle are present.
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Fig. 10. (a) Coronal intermediate weighted fat saturated MR image and (b) sagittal intermediate weighted fat saturated MR image, and (c) conventional radiograph of a 66-year-old woman with intense peritrochanteric pain because of a calcific tendonitis of the piriformis tendon (large arrowhead). Note the fluid collection in the trochanteric bursa (small arrowhead). The sagittal image shows the piriformis tendon (large arrowhead), the obturator internus (small arrow) and obturator externus tendon (thick arrow). The piriformis tendon (arrowhead) is thickened and has increased signal intensity. The calcified tendon of the piriformis muscle can be well identified (large arrowhead) on the conventional radiogram.
no intramuscular fat is visible. In Grade 1 some fatty streaks are present. In Grad 2 there is less fat than muscle tissue. In Grad 3 equal amounts of fat and muscle tissue are present and in Grad 4 there is more fatty tissue than muscle tissue (Fig. 9). Another reason for GTPS might be deposition of hydroxyapatite crystals in tendons about the greater trochanter. The hydroxyapatite crystal deposition disease or also called calcific tendonitis may cause painful inflammatory reaction. The most commonly affected sites are the rotator cuff tendons of the shoulder joint. However all the tendons of the body and especially the tendons about the greater trochanter may be affected as well. In MR imaging, the calcified deposit present with low signal intensity on all sequences. In the absence of an intense inflammatory reaction the calcific deposits might be easily overlooked. Conventional radio-
graphs may be very helpful for this diagnosis (Fig. 10). Even bone marrow edema or bone destruction may occasionally be associated with calcific tendonitis [15,16]. Therefore calcific tendonitis may be mistakenly diagnosed as malignancy or infection. The MRI pattern of diffuse bone edema adjacent to the tendon insertions at the greater trochanter, edema of the surrounding soft tissue and increased signal intensity of the tendon could also represent enthesitis in inflammatory diseases. Inflammation of the entheses, which represent the sites of attachment of tendons, ligaments, fasciae or joint capsules to bone, can occur all over the body. Peripheral enthesitis is a well known feature of ankylosing spondylitis (SpA) and other inflammatory diseases. Hip joint involvement in patients with SpA is common and early involvement seems to be a marker of sever disease [17].
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Fig. 11. Sagittal T1-weighted MR image in a 71-year-old man with total hip arthroplasty 4 years ago complaining of trochanteric pain and limping. After full thickness tear the gluteus minimus tendon can not be seen (thick arrow). Regular insertion of the gluteus medius tendon at the superoposterior facet of the greater trochanter (thin arrow). Metal artifacts (star) after THA.
Fig. 12. Coronal T2-weighted MR image in a 54-year-old woman with tenderness over the greater trochanter and abductor after THA two years ago. A fluid filled space between the retracted gluteus medius tendon (small arrows) and the tip of the greater trochanter (large arrow) can be seen. Filled star marks the artefact from the femoral component of the THA. Open star marks the gluteus medius muscle.
Fig. 13. Sagittal T1-weighted MR-images, presenting (a) normal anatomy of the gluteus minimus (A), gluteus medius (B) and the gluteus maximus (C) muscle. The symptomatic patient after THA in (b) shows the positive fan sign, representing a defect within the muscle tissue of the gluteus medius muscle (arrowheads).
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GTPS might also be caused by several entities that do not affect the hip abductors. For example snapping iliotibial band syndrom and Morel Lavallee lesions. Snapping iliotibial band syndrom describes the slipping of the iliotibial band over the greater trochanter [18]. Most cases are treated conservatively but if this fails open surgical treatment is performed by Z-plasty or by creating a defect on the iliotibial band. A rare cause for GTPS might be a Morel Lavallee lesion [19]. The Morel Lavallee lesion occurs most commonly after a trauma in the proximal thigh and over the greater trochanter and is characterized by a fluid collection in the subcutaneous tissue presenting as a pseudotumor.
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the muscle tissue of the gluteus medius muscle. The fan sign is assessed on sagittal T1-weighted images through the most lateral part of the greater trochanter (Fig. 13). This fan sign was significantly more frequently positive in the symptomatic patients than in the asymptomatic patients. In summary, MR imaging of the hip abductors is an important diagnostic tool to evaluate the reason for GTPS or limping in patients with or without THA. It can provide valuable additional information to achieve optimal treatment and outcomes.
References 4. Total hip arthroplasty Total hip arthroplasty (THA) is a highly effective procedure for patients with end-stage hip disease. Procedure volume increased 61% from 1995 to 2005 in the United States [20]. For THA the basic surgical approaches most commonly used are anterior, lateral, and posterior approaches. The lateral approach necessitates releasing the anterior tendinous portion from the greater trochanter and splitting the gluteus medius muscle. The posterior approach involves incision of the external rotators. For the anterior approach the plane between the tensor fasciae latae muscle and the rectus femoris muscle is identified and exposed. This is a true muscle sparing approach to the hip as it avoids any incision to the muscles in the front of the hip joint. The anterolateral approach for hip replacement surgery uses the intermuscular plane between the gluteus medius and tensor fasciae latae muscle. Local complications like mechanical aseptic loosening, foreign body reaction, infection or heterotopic new bone formation are well recognized as causes of delayed failure. Early failure includes infection, rapid acetabular wear or hip dislocation. Conventional radiography, imaging guided joint aspiration, conventional arthrography and bone scintigraphy are the available imaging modalities to evaluate complications after THA. However, the reason for GTPS and limping after THA might also be a soft-tissue abnormality [21,22], which may be missed by the aforementioned diagnostic tools. MR imaging is able to fill this diagnostic gap. MR imaging after THA is problematic because of susceptibility artifacts. Therefore MR imaging was not considered appropriate to assess possible THA complications. To decrease artifacts a wide reviewer bandwidth, fast spin-echo imaging [23] and small voxel sizes should be used [24]. Other strategies include the use of lower magnetic field strengths and the orientation of the frequency-encoding direction along the axis of the device [25]. With theses measures for metallic artifacts reduction assessment of abductor muscle tendon abnormalities is usually possible [26,27]. The effect of the different surgical approaches in THA on abductor function is discussed controversially [21,22,28]. In a prospective evaluation of MR imaging findings in asymptomatic and symptomatic patients after THA performed using a lateral approach [29] defects in the abductor tendons were rare in the asymptomatic patient group 8% had a defect in the gluteus minimus tendon (Fig. 11) and 16% had a defect in the gluteus medius tendon (Fig. 12). In symptomatic patients 56% gluteus minimus tendon defects and 62% gluteus medius tendon defects were seen. None of the asymptomatic patients had a defect of the posterior gluteus medius tendon. Although fluid collections around the greater trochanter were seen in both groups, fluid collections larger than 4 ml were seen only in the symptomatic patients. Fatty atrophy of the gluteus medius muscle was almost exclusively present in the symptomatic patients, whereas a significant difference in the degree of fatty atrophy of the gluteus minimus muscle could only be seen in the posterosuperior third of the muscle. In this study the positive fan sign is described, which represents a defect within
[1] Bunker TD, Esler CN, Leach WJ. Rotator-cuff tear of the hip. J Bone Joint Surg Br Vol 1997;79:618–20. [2] Pfirrmann CW, Chung CB, Theumann NH, Trudell DJ, Resnick D. Greater trochanter of the hip: attachment of the abductor mechanism and a complex of three bursae—MR imaging and MR bursography in cadavers and MR imaging in asymptomatic volunteers. Radiology 2001;221:469–77. [3] Kingzett-Taylor A, Tirman PF, Feller J, et al. Tendinosis and tears of gluteus medius and minimus muscles as a cause of hip pain: MR imaging findings. AJR Am J Roentgenol 1999;173:1123–6. [4] Bird PA, Oakley SP, Shnier R, Kirkham BW. Prospective evaluation of magnetic resonance imaging and physical examination findings in patients with greater trochanteric pain syndrome. Arthritis Rheum 2001;44:2138–45. [5] Blankenbaker DG, Ullrick SR, Davis KW, De Smet AA, Haaland B, Fine J. Correlation of MRI findings with clinical findings of trochanteric pain syndrome. Skeletal Radiol 2008;37:903–9. [6] Lequesne M, Djian P, Vuillemin V, Mathieu P. Prospective study of refractory greater trochanter pain syndrome. MRI findings of gluteal tendon tears seen at surgery. Clinical and MRI results of tendon repair. Joint Bone Spine 2008;75:458–64. [7] Chung CB, Robertson JE, Cho GJ, Vaughan LM, Copp SN, Resnick D. Gluteus medius tendon tears and avulsive injuries in elderly women: imaging findings in six patients. AJR Am J Roentgenol 1999;173:351–3. [8] Connell DA, Bass C, Sykes CA, Young D, Edwards E. Sonographic evaluation of gluteus medius and minimus tendinopathy. Eur Radiol 2003;13:1339–47. [9] Cvitanic O, Henzie G, Skezas N, Lyons J, Minter J. MRI diagnosis of tears of the hip abductor tendons (gluteus medius and gluteus minimus). AJR Am J Roentgenol 2004;182:137–43. [10] Howell GE, Biggs RE, Bourne RB. Prevalence of abductor mechanism tears of the hips in patients with osteoarthritis. J Arthroplasty 2001;16:121–3. [11] LaBan MM, Weir SK, Taylor RS. ‘Bald trochanter’ spontaneous rupture of the conjoined tendons of the gluteus medius and minimus presenting as a trochanteric bursitis. Am J Phys Med Rehabil/Assoc Acad Physiatrists 2004;83:806–9. [12] Pfahler M, Branner S, Refior HJ. Complete rotator cuff rupture—differential surgical techniques and intermediate-term results. Z Orthop Ihre Grenzgeb 1999;137:295–300. [13] Iannotti JP. Full-thickness rotator cuff tears: factors affecting surgical outcome. J Am Acad Orthop Surg 1994;2:87–95. [14] Goutallier D, Postel JM, Bernageau J, Lavau L, Voisin MC. Fatty muscle degeneration in cuff ruptures. Pre- and postoperative evaluation by CT scan. Clin Orthop Relat Res 1994:78–83. [15] Hayes CW, Rosenthal DI, Plata MJ, Hudson TM. Calcific tendinitis in unusual sites associated with cortical bone erosion. AJR Am J Roentgenol 1987;149:967–70. [16] Yang I, Hayes CW, Biermann JS. Calcific tendinitis of the gluteus medius tendon with bone marrow edema mimicking metastatic disease. Skeletal Radiol 2002;31:359–61. [17] Amor B. Value of various signs as diagnostic criteria of spondylarthropathies. Z Rheumatol 1994;53:230–3. [18] Ilizaliturri Jr VM, Martinez-Escalante FA, Chaidez PA, Camacho-Galindo J. Endoscopic iliotibial band release for external snapping hip syndrome. Arthroscopy 2006;22:505–10. [19] Mellado JM, Perez del Palomar L, Diaz L, Ramos A, Sauri A. Long-standing Morel–Lavallee lesions of the trochanteric region and proximal thigh: MRI features in five patients. AJR Am J Roentgenol 2004;182:1289–94. [20] Kelly MP, Bozic KJ. Cost drivers in total hip arthroplasty: effects of procedure volume and implant selling price. Am J Orthop 2009;38:E1–4. [21] Masonis JL, Bourne RB. Surgical approach, abductor function, and total hip arthroplasty dislocation. Clin Orthop Relat Res 2002:46–53. [22] Svensson O, Skold S, Blomgren G. Integrity of the gluteus medius after the transgluteal approach in total hip arthroplasty. J Arthroplasty 1990;5:57–60. [23] Eustace S, Jara H, Goldberg R, et al. A comparison of conventional spin-echo and turbo spin-echo imaging of soft tissues adjacent to orthopedic hardware. AJR Am J Roentgenol 1998;170:455–8. [24] Suh JS, Jeong EK, Shin KH, et al. Minimizing artifacts caused by metallic implants at MR imaging: experimental and clinical studies. AJR Am J Roentgenol 1998;171:1207–13. [25] Tormanen J, Tervonen O, Koivula A, Junila J, Suramo I. Image technique optimization in MR imaging of a titanium alloy joint prosthesis. J Magn Reson Imaging 1996;6:805–11.
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[26] Johnston C, Kerr J, Ford S, O’Byrne J, Eustace S. MRI as a problem-solving tool in unexplained failed total hip replacement following conventional assessment. Skeletal Radiol 2007;36:955–61. [27] Twair A, Ryan M, O’Connell M, Powell T, O’Byrne J, Eustace S. MRI of failed total hip replacement caused by abductor muscle avulsion. AJR Am J Roentgenol 2003;181:1547–50.
[28] Horwitz BR, Rockowitz NL, Goll SR, et al. A prospective randomized comparison of two surgical approaches to total hip arthroplasty. Clin Orthop Relat Res 1993:154–63. [29] Pfirrmann CW, Notzli HP, Dora C, Hodler J, Zanetti M. Abductor tendons and muscles assessed at MR imaging after total hip arthroplasty in asymptomatic and symptomatic patients. Radiology 2005;235:969–76.
Contents lists available at ScienceDirect
European Journal of Radiology journal homepage: www.elsevier.com/locate/ejrad
Review
The hip abductors at MR imaging A. Hoffmann ∗ , C.W.A. Pfirrmann 1 Department of Radiology, University Hospital Balgrist, Forchstrasse 340, CH-8008 Zürich, Switzerland
a r t i c l e
i n f o
Article history: Received 7 January 2010 Received in revised form 1 March 2010 Accepted 4 March 2010 Keywords: MRI Hip Tendon tear Greater trochanter pain syndrome
a b s t r a c t Imaging of the hip abductors plays an increasing role for the evaluation of greater trochanteric pain in patients with and without total hip arthroplasty. This review article addresses the anatomy of the hip abductors and their intervening bursae. It highlights different possible imaging appearances such as tendinopathy or partial and full thickness tears of the gluteal tendons. Muscle atrophy or fatty degeneration of the gluteal muscles is an important reason for limping. Inflammatory diseases such as hydroxyapatite crystal deposition disease or spondylarthritis have to be considered. Knowledge of these different entities is important to achieve optimal treatment and outcomes. © 2010 Elsevier Ireland Ltd. All rights reserved.
1. Introduction
2. Anatomy
Orthopedic surgeons and rheumatologists show an increasing interest in imaging of the greater trochanter and abductors tendons. Greater trochanteric pain syndrom (GTPS) is a clinical term characterized by chronic pain and tenderness over the lateral aspect of the hip. Exacerbation of pain while lying on the affected side or while climbing stairs is typical. GTPS may have several differential diagnoses. The clinical term trochanteric bursitis suggested that bursitis is the only reason for the pain. However, in addition to primary bursitis, a fluid filled bursa may be secondary to disorders of abductor tendons of the hip. Magnetic resonance imaging (MRI) has shown that patients with GTPS often present with tendinopathy or tears of the abductor tendons. Tears of the abductor tendons have also been termed “rotator cuff tears of the hip” [1]. Imaging of the greater trochanter and the abductors tendons in patients after total hip arthroplasty (THA) suffering from trochanteric pain and limping is of increasing interest for hip surgeons. Detailed knowledge of the anatomy and the typical abnormal findings of the hip abductors and their intervening bursae are necessary to assess the reasons for GTPS or pain after THA and to initiate an effective treatment.
The greater trochanter has four distinct osseous facets that serve as specific tendon attachments and sites for bursae [2]. The anterior facet, best seen on axial images, serves as attachment of the gluteus minimus tendon (Fig. 1). The superoposterior facet, best seen on sagittal or coronal images, is covered by the main tendon of the gluteus medius muscle (Fig. 2). The lateral facet, best seen in coronal plane, is in contact with the superoposterior facet and is covered by the lateral part of the gluteus medius tendon (Fig. 3). There is no tendon attachment to the posterior facet, which is covered by the trochanteric bursa (TrB) (Fig. 4). The attachment of the gluteus medius tendon has three different parts (posterior, lateral, anterior part). The posterior part is the strong main tendon of the gluteus medius covering the superoposterior facet. The posterior part arises from the central posterior portion of the gluteus medius muscle and shows a coronal oblique orientation. The lateral part of the gluteus medius, covering the lateral facet, arises from the undersurface of the gluteus medius muscle and attaches to lower part of the lateral facet. The anterior part of the gluteus medius is usually a muscular attachment and attaches interiorly onto the tendon of the gluteus minimus tendon. The attachment of the gluteus minimus tendon can be divided into two components (Lateral, medial part). The lateral part of the gluteus minimus tendon consists of the main tendon, covering the lateral aspect of the anterior facet, and arises from the superficial part of the muscle fascia. The medial part of the gluteus minimus tendon shows a muscular insertion in the anterior and superior capsule of the hip joint. Bursae around the greater trochanter are very variable and tend to be more frequent in older individuals. Three bursae are consistently present in most individuals. The Trochanteric
∗ Corresponding author. Tel.: +41 44 386 1111; fax: +41 44 386 3309. E-mail addresses: [email protected] (A. Hoffmann), christian.pfi[email protected] (C.W.A. Pfirrmann). 1 Tel.: +41 44 386 1111; fax: +41 44 386 3309. 0720-048X/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrad.2010.03.002
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Fig. 1. Coronal T1-weighted MR image showing the normal gluteus minimus tendon (arrows) inserting at the anterior facet of the greater trochanter.
bursa (TrB) is the largest bursa, covering the posterior facet of the greater trochanter. The subgluteus medius bursa (SGMeB) is located between the superior part of the lateral facet and the lateral part of the gluteus medius tendon (Fig. 5). The subgluteus minimus bursa (SGMiB) lies beneath the gluteus minimus tendon, medial and superior to its insertion. In contrast to the SGMeB and the SGMiB the normal TrB can sometimes be detected on axial images, because it is surrounded by fat on both sides. Some authors use the term subgluteus maximus bursa synonymously with the TrB.
Fig. 3. Coronal T1-weighted MR image in a patient with a normal gluteus medius tendon. The lateral part of the gluteus medius tendon (arrow) inserts at the lateral facet of the greater trochanter. The open arrowhead points to the trochanteric bald spot.
3. Abnormal findings One of the possible reasons for GTPS is an abnormality of the gluteus medius or gluteus minimus tendon [3,4]. Several studies
Fig. 2. (a) Coronal and (b) sagittal T1-weighted MR image. The main part of the gluteus medius tendon (arrow) inserts at the superoposterior facet of the greater trochanter. On the sagittal image the insertion of the gluteus minimus tendon (arrowhead) at the anterior facet and the insertion of the main part of the gluteus medius tendon (arrow) at the superoposterior facet can be seen.
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Fig. 4. Axial T2-weighted fat-saturated MR image in a patient with trochanteric bursitis. The fluid-filled trochanteric bursa (arrow) covers the posterior facet of the greater trochanter.
could show that tendinopathy of the abductor tendons is significantly associated with lateral hip pain. Tendinopathy is usually characterized by increased signal of the tendon on T1w images (Fig. 6), while the fluid sensitive image is largely normal. A partial thickness tear is diagnosed by increased signal intensity on fluid sensitive images (Fig. 7). A full thickness tear consists of discontinuity of the tendon (Figs. 5 and 8). Blankenbaker et al. [5] showed that high signal intensity around the abductor tendon as well as bursal fluid and peritrochanteric edema can also be found in asymptomatic patients. In up to 22% patients undergoing surgery for femoral neck fractures, tears of the gluteus medius and gluteus minimus tendons were found [1]. Typical patients with tears of the abductor tendons are elderly women. Lequesne et al.
Fig. 5. Coronal T2-weighted fat-saturated MR image in a 68-year-old patient with left trochanteric pain. Full thickness tear of the lateral part of the gluteus medius tendon (arrowheads) and a fluid filled subgluteus medius bursa (arrows) are shown.
[6] compared MRI and surgical findings in patients with refractory GTPS. In this prospective study tears of the lateral part of the gluteus medius tendon were confirmed at surgery. Isolated tears of the gluteus minimus tendon were not seen. In this study tears were never located at the myotendinous junction. Correlation between MRI and surgery was also done by Chung et al. [7]. For three patients surgery revealed findings that corresponded with those of MRI. Gluteus medius tendon tears seem to be more frequent compared to gluteus minimus tendon tears [3,8] and most of them appear at the anterior portion at the lateral facet of the
Fig. 6. (a) Sagittal T1-weighted MR image showing a tendinopathy of the gluteus minimus (thin arrow) and the gluteus medius (thick arrow) tendon. Note the detachment of an ossicle (arrowhead) from the greater trochanter. (b) Coronal T2-weighted MR image in an 84-year-old woman with GTPS after THA demonstrating an osseous (arrowhead) detachment of the medius tendon (black arrow). The filled star marks the femoral component of the THA.
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Fig. 7. Coronal intermediate-weighted fat saturated MR image of a 67-year-old woman with refractory lateral hip pain. Note the partial tear of the gluteus minimus tendon (arrowheads) with increased signal and thickening of the tendon. Gluteus minimus muscle (star).
trochanter [4]. Cvitanic and coworkers could show in a study based on surgical findings of 21 consecutive patients, that gluteus medius and gluteus minimus tendons are torn with similar frequency [9]. Women are four times more frequently affected compared to men [1,10]. To avoid overestimation of the tendon detachment it is essential to be aware of an area devoid of a tendon attachment on the lateral facet of the trochanter (Fig. 3). This area is situated between the attachment of the gluteus medius tendon and the capsular portion of the gluteus minimus tendon. It is referred to as the trochanteric bald spot and gluteus medius tendon tear of each of its attachment sites has been described as producing a “bald trochanter” [11]. Addressing muscle atrophy or fatty degeneration of the abductor muscles are as important as assessing the integrity of the abductor tendons. Studies on the results of surgical repair of rotator cuff tears of the shoulder have shown that one of the preoperative factors associated with a less favorable result is poor muscle quality [12,13]. Atrophy and fatty degeneration of the abductor muscles may be graded using a classification system originally developed for the rotator cuff muscles of the shoulder [14] using transverse T1-weighted or T2-weighted non-fat saturated images. In Grad 0
Fig. 8. (a) Coronal T2-weighted non fat saturated and (b) axial intermediate-weighted fat saturated MR image in a 60-year-old woman with GTPS. A full detachment of the conjoined aponeurosis (arrowhead) between the gluteus medius tendon (muscle marked with full star) and the vastus lateralis (muscle marked with open star) from the greater trochanter can be seen.
Fig. 9. Axial T1-weighted MR images. (a) Normal anatomy of the gluteus minimus (A), gluteus medius (B) and gluteus maximus (C) muscles without atrophy or fatty degeneration. (b) Fatty degeneration Grad 4 of the gluteus minimus muscle (A) and Grad 2 of the gluteus medius (B) and maximus (C) muscle are present.
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Fig. 10. (a) Coronal intermediate weighted fat saturated MR image and (b) sagittal intermediate weighted fat saturated MR image, and (c) conventional radiograph of a 66-year-old woman with intense peritrochanteric pain because of a calcific tendonitis of the piriformis tendon (large arrowhead). Note the fluid collection in the trochanteric bursa (small arrowhead). The sagittal image shows the piriformis tendon (large arrowhead), the obturator internus (small arrow) and obturator externus tendon (thick arrow). The piriformis tendon (arrowhead) is thickened and has increased signal intensity. The calcified tendon of the piriformis muscle can be well identified (large arrowhead) on the conventional radiogram.
no intramuscular fat is visible. In Grade 1 some fatty streaks are present. In Grad 2 there is less fat than muscle tissue. In Grad 3 equal amounts of fat and muscle tissue are present and in Grad 4 there is more fatty tissue than muscle tissue (Fig. 9). Another reason for GTPS might be deposition of hydroxyapatite crystals in tendons about the greater trochanter. The hydroxyapatite crystal deposition disease or also called calcific tendonitis may cause painful inflammatory reaction. The most commonly affected sites are the rotator cuff tendons of the shoulder joint. However all the tendons of the body and especially the tendons about the greater trochanter may be affected as well. In MR imaging, the calcified deposit present with low signal intensity on all sequences. In the absence of an intense inflammatory reaction the calcific deposits might be easily overlooked. Conventional radio-
graphs may be very helpful for this diagnosis (Fig. 10). Even bone marrow edema or bone destruction may occasionally be associated with calcific tendonitis [15,16]. Therefore calcific tendonitis may be mistakenly diagnosed as malignancy or infection. The MRI pattern of diffuse bone edema adjacent to the tendon insertions at the greater trochanter, edema of the surrounding soft tissue and increased signal intensity of the tendon could also represent enthesitis in inflammatory diseases. Inflammation of the entheses, which represent the sites of attachment of tendons, ligaments, fasciae or joint capsules to bone, can occur all over the body. Peripheral enthesitis is a well known feature of ankylosing spondylitis (SpA) and other inflammatory diseases. Hip joint involvement in patients with SpA is common and early involvement seems to be a marker of sever disease [17].
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Fig. 11. Sagittal T1-weighted MR image in a 71-year-old man with total hip arthroplasty 4 years ago complaining of trochanteric pain and limping. After full thickness tear the gluteus minimus tendon can not be seen (thick arrow). Regular insertion of the gluteus medius tendon at the superoposterior facet of the greater trochanter (thin arrow). Metal artifacts (star) after THA.
Fig. 12. Coronal T2-weighted MR image in a 54-year-old woman with tenderness over the greater trochanter and abductor after THA two years ago. A fluid filled space between the retracted gluteus medius tendon (small arrows) and the tip of the greater trochanter (large arrow) can be seen. Filled star marks the artefact from the femoral component of the THA. Open star marks the gluteus medius muscle.
Fig. 13. Sagittal T1-weighted MR-images, presenting (a) normal anatomy of the gluteus minimus (A), gluteus medius (B) and the gluteus maximus (C) muscle. The symptomatic patient after THA in (b) shows the positive fan sign, representing a defect within the muscle tissue of the gluteus medius muscle (arrowheads).
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GTPS might also be caused by several entities that do not affect the hip abductors. For example snapping iliotibial band syndrom and Morel Lavallee lesions. Snapping iliotibial band syndrom describes the slipping of the iliotibial band over the greater trochanter [18]. Most cases are treated conservatively but if this fails open surgical treatment is performed by Z-plasty or by creating a defect on the iliotibial band. A rare cause for GTPS might be a Morel Lavallee lesion [19]. The Morel Lavallee lesion occurs most commonly after a trauma in the proximal thigh and over the greater trochanter and is characterized by a fluid collection in the subcutaneous tissue presenting as a pseudotumor.
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the muscle tissue of the gluteus medius muscle. The fan sign is assessed on sagittal T1-weighted images through the most lateral part of the greater trochanter (Fig. 13). This fan sign was significantly more frequently positive in the symptomatic patients than in the asymptomatic patients. In summary, MR imaging of the hip abductors is an important diagnostic tool to evaluate the reason for GTPS or limping in patients with or without THA. It can provide valuable additional information to achieve optimal treatment and outcomes.
References 4. Total hip arthroplasty Total hip arthroplasty (THA) is a highly effective procedure for patients with end-stage hip disease. Procedure volume increased 61% from 1995 to 2005 in the United States [20]. For THA the basic surgical approaches most commonly used are anterior, lateral, and posterior approaches. The lateral approach necessitates releasing the anterior tendinous portion from the greater trochanter and splitting the gluteus medius muscle. The posterior approach involves incision of the external rotators. For the anterior approach the plane between the tensor fasciae latae muscle and the rectus femoris muscle is identified and exposed. This is a true muscle sparing approach to the hip as it avoids any incision to the muscles in the front of the hip joint. The anterolateral approach for hip replacement surgery uses the intermuscular plane between the gluteus medius and tensor fasciae latae muscle. Local complications like mechanical aseptic loosening, foreign body reaction, infection or heterotopic new bone formation are well recognized as causes of delayed failure. Early failure includes infection, rapid acetabular wear or hip dislocation. Conventional radiography, imaging guided joint aspiration, conventional arthrography and bone scintigraphy are the available imaging modalities to evaluate complications after THA. However, the reason for GTPS and limping after THA might also be a soft-tissue abnormality [21,22], which may be missed by the aforementioned diagnostic tools. MR imaging is able to fill this diagnostic gap. MR imaging after THA is problematic because of susceptibility artifacts. Therefore MR imaging was not considered appropriate to assess possible THA complications. To decrease artifacts a wide reviewer bandwidth, fast spin-echo imaging [23] and small voxel sizes should be used [24]. Other strategies include the use of lower magnetic field strengths and the orientation of the frequency-encoding direction along the axis of the device [25]. With theses measures for metallic artifacts reduction assessment of abductor muscle tendon abnormalities is usually possible [26,27]. The effect of the different surgical approaches in THA on abductor function is discussed controversially [21,22,28]. In a prospective evaluation of MR imaging findings in asymptomatic and symptomatic patients after THA performed using a lateral approach [29] defects in the abductor tendons were rare in the asymptomatic patient group 8% had a defect in the gluteus minimus tendon (Fig. 11) and 16% had a defect in the gluteus medius tendon (Fig. 12). In symptomatic patients 56% gluteus minimus tendon defects and 62% gluteus medius tendon defects were seen. None of the asymptomatic patients had a defect of the posterior gluteus medius tendon. Although fluid collections around the greater trochanter were seen in both groups, fluid collections larger than 4 ml were seen only in the symptomatic patients. Fatty atrophy of the gluteus medius muscle was almost exclusively present in the symptomatic patients, whereas a significant difference in the degree of fatty atrophy of the gluteus minimus muscle could only be seen in the posterosuperior third of the muscle. In this study the positive fan sign is described, which represents a defect within
[1] Bunker TD, Esler CN, Leach WJ. Rotator-cuff tear of the hip. J Bone Joint Surg Br Vol 1997;79:618–20. [2] Pfirrmann CW, Chung CB, Theumann NH, Trudell DJ, Resnick D. Greater trochanter of the hip: attachment of the abductor mechanism and a complex of three bursae—MR imaging and MR bursography in cadavers and MR imaging in asymptomatic volunteers. Radiology 2001;221:469–77. [3] Kingzett-Taylor A, Tirman PF, Feller J, et al. Tendinosis and tears of gluteus medius and minimus muscles as a cause of hip pain: MR imaging findings. AJR Am J Roentgenol 1999;173:1123–6. [4] Bird PA, Oakley SP, Shnier R, Kirkham BW. Prospective evaluation of magnetic resonance imaging and physical examination findings in patients with greater trochanteric pain syndrome. Arthritis Rheum 2001;44:2138–45. [5] Blankenbaker DG, Ullrick SR, Davis KW, De Smet AA, Haaland B, Fine J. Correlation of MRI findings with clinical findings of trochanteric pain syndrome. Skeletal Radiol 2008;37:903–9. [6] Lequesne M, Djian P, Vuillemin V, Mathieu P. Prospective study of refractory greater trochanter pain syndrome. MRI findings of gluteal tendon tears seen at surgery. Clinical and MRI results of tendon repair. Joint Bone Spine 2008;75:458–64. [7] Chung CB, Robertson JE, Cho GJ, Vaughan LM, Copp SN, Resnick D. Gluteus medius tendon tears and avulsive injuries in elderly women: imaging findings in six patients. AJR Am J Roentgenol 1999;173:351–3. [8] Connell DA, Bass C, Sykes CA, Young D, Edwards E. Sonographic evaluation of gluteus medius and minimus tendinopathy. Eur Radiol 2003;13:1339–47. [9] Cvitanic O, Henzie G, Skezas N, Lyons J, Minter J. MRI diagnosis of tears of the hip abductor tendons (gluteus medius and gluteus minimus). AJR Am J Roentgenol 2004;182:137–43. [10] Howell GE, Biggs RE, Bourne RB. Prevalence of abductor mechanism tears of the hips in patients with osteoarthritis. J Arthroplasty 2001;16:121–3. [11] LaBan MM, Weir SK, Taylor RS. ‘Bald trochanter’ spontaneous rupture of the conjoined tendons of the gluteus medius and minimus presenting as a trochanteric bursitis. Am J Phys Med Rehabil/Assoc Acad Physiatrists 2004;83:806–9. [12] Pfahler M, Branner S, Refior HJ. Complete rotator cuff rupture—differential surgical techniques and intermediate-term results. Z Orthop Ihre Grenzgeb 1999;137:295–300. [13] Iannotti JP. Full-thickness rotator cuff tears: factors affecting surgical outcome. J Am Acad Orthop Surg 1994;2:87–95. [14] Goutallier D, Postel JM, Bernageau J, Lavau L, Voisin MC. Fatty muscle degeneration in cuff ruptures. Pre- and postoperative evaluation by CT scan. Clin Orthop Relat Res 1994:78–83. [15] Hayes CW, Rosenthal DI, Plata MJ, Hudson TM. Calcific tendinitis in unusual sites associated with cortical bone erosion. AJR Am J Roentgenol 1987;149:967–70. [16] Yang I, Hayes CW, Biermann JS. Calcific tendinitis of the gluteus medius tendon with bone marrow edema mimicking metastatic disease. Skeletal Radiol 2002;31:359–61. [17] Amor B. Value of various signs as diagnostic criteria of spondylarthropathies. Z Rheumatol 1994;53:230–3. [18] Ilizaliturri Jr VM, Martinez-Escalante FA, Chaidez PA, Camacho-Galindo J. Endoscopic iliotibial band release for external snapping hip syndrome. Arthroscopy 2006;22:505–10. [19] Mellado JM, Perez del Palomar L, Diaz L, Ramos A, Sauri A. Long-standing Morel–Lavallee lesions of the trochanteric region and proximal thigh: MRI features in five patients. AJR Am J Roentgenol 2004;182:1289–94. [20] Kelly MP, Bozic KJ. Cost drivers in total hip arthroplasty: effects of procedure volume and implant selling price. Am J Orthop 2009;38:E1–4. [21] Masonis JL, Bourne RB. Surgical approach, abductor function, and total hip arthroplasty dislocation. Clin Orthop Relat Res 2002:46–53. [22] Svensson O, Skold S, Blomgren G. Integrity of the gluteus medius after the transgluteal approach in total hip arthroplasty. J Arthroplasty 1990;5:57–60. [23] Eustace S, Jara H, Goldberg R, et al. A comparison of conventional spin-echo and turbo spin-echo imaging of soft tissues adjacent to orthopedic hardware. AJR Am J Roentgenol 1998;170:455–8. [24] Suh JS, Jeong EK, Shin KH, et al. Minimizing artifacts caused by metallic implants at MR imaging: experimental and clinical studies. AJR Am J Roentgenol 1998;171:1207–13. [25] Tormanen J, Tervonen O, Koivula A, Junila J, Suramo I. Image technique optimization in MR imaging of a titanium alloy joint prosthesis. J Magn Reson Imaging 1996;6:805–11.
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[26] Johnston C, Kerr J, Ford S, O’Byrne J, Eustace S. MRI as a problem-solving tool in unexplained failed total hip replacement following conventional assessment. Skeletal Radiol 2007;36:955–61. [27] Twair A, Ryan M, O’Connell M, Powell T, O’Byrne J, Eustace S. MRI of failed total hip replacement caused by abductor muscle avulsion. AJR Am J Roentgenol 2003;181:1547–50.
[28] Horwitz BR, Rockowitz NL, Goll SR, et al. A prospective randomized comparison of two surgical approaches to total hip arthroplasty. Clin Orthop Relat Res 1993:154–63. [29] Pfirrmann CW, Notzli HP, Dora C, Hodler J, Zanetti M. Abductor tendons and muscles assessed at MR imaging after total hip arthroplasty in asymptomatic and symptomatic patients. Radiology 2005;235:969–76.