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peer 20 12 / 13 review Le-Anne Grimshaw, Chief Sonographer, Mater Imaging, North Sydney, Lecturer Musculoskeletal Sonography and Advancements in Ultrasound, Curtin University, WA Ultrasound for athletic pubalgia Dear Expert, I am scanning an increasing number of young sports people with groin pain. What pathology might I expect to see in the absence of a hernia? Introduction Athletic pubalgia is the term given to groin pain experienced while playing sport. It is also called groin strain, sportsman’s hernia, Gilmore’s groin, athletic hernia and groin disruption. It is commonly seen in sports that involve side-toside cutting, quick accelerations and decelerations, and sudden directional changes and often observed in players of soccer, AFL, ice hockey, field hockey and tennis. However, athletic pubalgia is not confined to elite athletes and is found in school athletes and weekend warriors. Pain can range from mild episodes of discomfort to chronic career-ending pain. It is vital to diagnose the exact source of the injury so it can be treated effectively as, if misdiagnosed, the wrong exercises can exacerbate the irritation. Almost 20% of all sports injuries are related to the groin [1–4]. Athletic pubalgia Table 1. Areas affected by athletic pubalgia 1. Anterior hip joint Rectus femoris, sartorius, tensor 2. fascia lata (TFL) 3. Iliopsoas tendon 4. Pubis – pubic tubercle 5. Adductor longus Common rectus abdominis – 6. adductor origin 7. Conjoint tendon 8. Inguinal ligament Rectus abdominis, external 9. oblique, internal oblique, transverse abdominis muscles 10. Ilioinguinal nerve Inguinal and femoral canals and 11. rectus sheath 18 soundeffects is the third highest cause of injury leading to time off the playing field, after fractures and anterior cruciate ligament reconstructions [3]. It is a frustrating injury, often intermittent and poorly localised. It can be difficult for the clinician to pinpoint the exact nature of the injury and therefore is difficult to treat. Groin pain in sports people is usually clinically diagnosed as an inguinal hernia or adductor strain. However, tendinous and ligamentous pathologies centred around the pubic tubercle are the most common cause of groin pain, with muscle strains and tears and nerve entrapment syndromes also to be considered. Table 1 lists the areas that can be imaged with ultrasound in a patient with athletic pubalgia. The ultrasonic anatomy and pathology of these structures will be reviewed. For the purpose of this paper, inguinal, femoral and spigelian hernias will not be discussed. Clinical presentation The player may experience sudden and acute pain while on the playing field or there might be an insidious onset of pain that is poorly localised. The pain may be centred over the conjoint tendon and inguinal canal or it may radiate to the adductor region and into the scrotum/labia. It may increase with sudden movements such as coughing, sneezing, or performing a resisted sit up [5]. There can often be more than one pathology causing the pain. For external oblique muscle rectus abdominus muscle internal oblique muscle transverse abdominus muscle ilioinguinal nerve conjoint tendon hip joint inguinal ligament lesser trochanter iliopsoas insertion spermatic cord adductor origin attachment Fig 1. Anatomy of the pelvis showing the relationship of the structures mentioned in Table 1 [12] Ultrasound for athletic pubalgia example, it would not be unusual to have adductor tendinopathy, osteitis pubis and a sportsman’s hernia coexisting. This makes the clinical diagnosis even more problematic. Conservative treatment is not always ideal for these people, particularly in the elite sports person who wants to get back to the playing field as soon as possible [5]. Ultrasound is an excellent tool for diagnosing the pathology listed in Table 2. When performing the ultrasound, it is important to always scan the contralateral side and to use a clinician’s touch while scanning. For the ultrasound examination, the patient lies supine on the table with the legs comfortably extended and is asked to identify the area of pain. In some instances, they may move their leg or perform a sit up to attempt to elicit the pain to further target the exact region of soreness. The anatomy, scanning technique and ultrasonic pathological appearances of the causes of athletic pubalgia, Table 2. Pathology that may cause athletic pubalgia Adductor longus dysfunction Osteitis pubis Posterior inguinal wall deficiency Hip joint pathology Labral tears Femoro-acetabular impingement Tendinosis or tears of any of the following muscles: Rectus abdominis, rectus femoris, sartorius, tensor fascia lata (TFL) Nerve entrapment syndromes – Ilioinguinal nerve A peer review as outlined in Tables 1 and 2, will be discussed. Anterior hip joint The hip joint is a ball and socket joint and is covered by a homogeneous, echogenic triangular-shaped labrum. The entire joint is then covered with a fibrous capsule containing multiple ligaments that attach distally to the neck of the femur [8]. To image the hip joint, the ultrasound probe is positioned in a longitudinal plane over the anterior groin crease (fig 2). Pathology An intra-articular joint effusion may be seen at the level of the femoral neck where fluid displaces the ligaments anteriorly. Comparison with the normal contralateral side will show a difference in the capsular thickness (fig 3). A difference of 2 mm or more is suggestive of a significant joint effusion [10]. Martinoli also suggests an increased thickness of the joint capsule greater than 7 mm is indicative of a joint effusion [11]. Labral tears are seen as anechoic defects in the labrum (fig 4). Paralabral cysts may also be identified which are a secondary sign of a tear [9]. Loose bodies are echogenic foci seen within the joint and can be large enough to cause impingement and pain with hip movements. Labral ossicles are exostoses of bone that can cause femoroacetabular impingement and pain (fig 4). B Figs 3A and 3B. Longitudinal image of the femoral neck (callipers). (A) joint effusion with bulging of the ligaments and an increased measurement. (B) normal femoral neck image A Fig 2. Photograph showing positioning of the transducer for the anterior hip joint with the patient lying supine and the legs comfortably relaxed Rectus femoris, sartorius and tensor fascia lata muscles The rectus femoris muscle has a broad attachment onto the anterior inferior iliac spine (AIIS) and ilium superior to the acetabulum [8]. To image the rectus femoris origin, from the anterior hip joint position, the probe is moved slightly superiorly. The sartorius muscle attaches proximally to the anterior superior iliac spine (ASIS) and courses immediately medially to insert distally onto the proximal, medial portion of the tibia [8]. Position the transducer transversely over the ASIS and move it inferiorly. The sartorius is seen as it moves medially across the hip joint. The tensor fascia lata (TFL) muscle has a thin tendinous insertion onto the lateral portion of the ASIS and then blends with the iliotibial band that then attaches to the lateral condyle of the tibia [8]. It is best B Figs 4A and 4B. Longitudinal images of the hip joint. (A) shows a labral ossicle as an echogenic linear structure in the labrum. (B) tear of the labrum (callipers) ISSUE 2 2013 19 peer Ultrasound for athletic pubalgia review scanned with the patient lying on their side. The probe is placed in a longitudinal plane over the ASIS with the depth reduced to about 3–4 cm to assess the tendinous insertion onto ASIS and then increased to visualise the muscular component. Pathology A muscle strain on ultrasound appears as increased echogenicity of the muscle. It can be focal or diffuse (fig14). A partial tear in a muscle may be intrasubstance – along the fibres of the muscle where a linear hypoechoic or anechoic cleft is seen in a thickened muscle. A full thickness tear is seen as a defect that traverses the entire width of the muscle. Heterogeneous or anechoic haematoma may be seen to fill the gap of the defect (fig 5). Iliopsoas tendon The iliopsoas is comprised of the psoas major, psoas minor and iliacus muscles. The distal tendon insertion is onto the lesser trochanter of the femur [8]. This is best visualised on ultrasound with the patient’s knee flexed and hip abducted (fig 6). Starting with the probe in a longitudinal plane over the anterior hip joint, it is then moved slightly medially where the tendon of the iliopsoas is seen crossing the joint. Keeping the tendon in view, slide the probe inferiorly and slightly medially to the lesser trochanter. This tendon should also be imaged dynamically in transverse at the level of the hip joint to check for a snapping iliopsoas tendon. The tendon should glide smoothly over the iliopectineal eminence as the patient straightens the leg. Pathology Snapping iliopsoas The iliopsoas tendon can become enlarged and tendinopathic as it ‘bumps’ over a prominent iliopectineal eminence. The tendon is scanned in a transverse orientation over the hip joint with the patient’s leg abducted and flexed and then watch the movement of the iliopsoas tendon as the patient straightens and extends the leg. The patient will complain of feeling a click over the anterior hip joint. This click will also be felt and seen during the dynamic scan. As the patient straightens the leg, the tendon will have a jerky motion instead of a smooth glide. Iliopsoas bursitis This is a distension of the bursa around the iliopsoas tendon. This is an inflammatory condition caused by excessive flexion and extension in athletes [7]. On ultrasound, the tendon may appear thickened and there will be a hypoechoic collection around the tendon, often medially. A curvi-linear probe may demonstrate the bursitis more clearly and can be used for injections into the bursa as it may display the needle more clearly. 20 soundeffects portion of this is the pubic crest. Pubic tubercles arise from the lateral end of each side of the crest [8]. The transducer is positioned in a transverse orientation directly over the pubic bones. Pathology Osteitis pubis may be seen on X-ray as erosions at the subchondral bone on either side of the symphysis. These bony irregularities will also be seen on ultrasound along with thickening and hypertrophy of the joint capsule and ligaments (fig 7). It often coexists with rectus abdominis-adductor dysfunction. Pubis Adductor longus The inferior part of the pelvis is formed by the pubis anteriorly and the ischium posteriorly. The pubis is divided into the body and two rami. The right and left pubic bodies are joined by the strong fibrous symphysis pubis. The superior The adductor longus attaches to the body A Fig 5. Longitudinal image of TFL insertion with a full thickness tear of the tendon (calipers) Fig 6. Photograph showing positioning of the patient and the transducer for iliopsoas tendon imaging in long of the pubis inferior to the pubic crest [8]. Pathology Adductor longus dysfunction can be a precursor to osteitis pubis. Bony erosions B Figs 7A and 7B. Image over the pubis. (A) normal smooth delineation of the pubic crest either side of the hypoechoic symphysis pubis. (B) osteitis pubis with irregular bony surface of the pubic bones, which was also very tender with probe pressure Ultrasound for athletic pubalgia A Fig 8. X-ray of a pelvis showing the anatomical insertions of rectus abdominus and adductor longus (red), conjoint tendon (blue) inguinal ligament (green) and the common rectus abdominis – adductor origin (white) Pathology origin onto the pubis. There may be pain Tendinopathy of the origin will demonstrate increased thickness and heterogeneity compared to the contralateral side and will be tender with probe pressure (fig 9). It can be in isolation or can be associated with osteitis pubis and adductor tendinopathy (fig 10). The transducer is pressed up against the inferior portion of the pubis in a longitudinal plane. The patient may abduct the leg slightly to allow better access to the adductor origin. Adductor tendinopathy is seen on ultrasound as a thickened, heterogeneous tendon origin with bony irregularity that is tender to press (fig 10). Partial tearing of the origin and/or muscle may be seen as discrete anechoic clefts. There may be multiple tears seen. A full thickness tear of adductor longus will demonstrate retraction of the muscle with haematoma filling the gap in the acute phase. Common rectus abdominis – adductor origin The rectus abdominis muscle inserts from a superior course onto the pubic tubercle and the adductor tendon inserts from an inferior course onto the pubic tubercle. The two tendon insertions merge to form a common origin (fig 8). To image the common rectus abdominis – adductor origin, the transducer is positioned in a longitudinal plane with the mid part of the probe resting on the pubic tubercle, slightly to the left and then right of the midline. review B Fig 9. Image of the common rectus abdominis – adductor origin, in long. (A) when the probe is placed on the right pubic tubercle over the common rectus abdominus – adductor origin the pain was extreme and localised. The common origin is thicker and heterogeneous compared to the contralateral normal side in image (B) can be seen on ultrasound at the tendon with probe pressure. peer Conjoint tendon The conjoint tendon is the aponeurosis of the internal oblique and transverse abdominis muscles which form the roof and posterior wall of the inguinal canal [8]. Pathology Sportsman’s hernia Inflammation of the conjoint tendon and periostium at the adductor origin causes the tendon to thicken up and lose its elasticity. This leads to posterior inguinal wall deficiency where the wall is displaced anteriorly rather than becoming taut when the patient strains. On ultrasound, the conjoint tendon appears thicker and the inguinal canal loses its ‘bounce’ with straining (fig 11). Instead of the inguinal canal going from a horizontal position at rest to a vertical position on strain, the canal remains horizontal with little movement (fig 12). This condition often It has always been thought to attach onto the pubic crest. However, new fresh cadaveric research has shown that this aponeurosis may instead merge into the anterior sheath of the lateral aspect of rectus abdominis (fig 8) [7]. coexists with osteitis pubis and adductor To image the conjoint tendon, first find the internal oblique and transverse abdominis muscles in a transverse plane at the level of the ASIS. Follow the two muscles distally. As you slide the probe inferiorly, the muscles will reduce in size eventually joining to form the conjoint tendon. Rotate the probe so it is running along the length of the conjoint tendon. This is seen as an echogenic thin band that merges with the rectus abdominis, which then in turn attaches to the pubic crest. Inguinal ligament Always image both sides in a dual format to better compare size and echogenicity of this structure. tendinosis. It is thought excessive adductor action creates shearing forces across the pubic symphysis that stress the posterior inguinal wall, resulting in posterior inguinal wall deficiency [5]. The inguinal ligament is the aponeurosis of the external oblique muscle and is seen as a fibrous band between the ASIS and the pubic crest (fig 8). It forms the floor and anterior wall of the inguinal canal [8]. From the common rectus abdominis – adductor position, the superior part of the transducer is rotated towards the iliac crest. The ligament is a thin, 2 mm linear fibrillar structure seen coursing between the ASIS and the pubic crest. In men, the spermatic cord can be seen crossing over the distal end of the ligament. ISSUE 2 2013 21 peer Ultrasound for athletic pubalgia review A Fig 10A. Transverse image of the pubis. Unilateral osteitis pubis with common rectus abdominis – adductor origin tendinopathy and associated adductor tendinopathy Pathology Repeated stretching or sudden force can lead to injury to the inguinal ligament. The ligament appears thicker and hypoechoic on ultrasound when compared to the contralateral side, and is often tender with probe pressure (fig 13). Rectus abdominis, external oblique, internal oblique and transverse abdominis muscles The rectus abdominis originates from the pubic crest and pubic symphysis and extends superiorly and longitudinally to the xiphoid process and 5th and 7th costal cartilages [8]. The external oblique, internal oblique and transverse abdominis muscles are the flat anterolateral abdominal muscles that support the anterolateral abdominal wall, maintaining posture and exerting firm pressure on the visceral organs, protecting them from injury [8]. C B Figs 10B and 10C. Longitudinal image of the adductor origin. Same patient as fig 11A. (B) irregular bony margin of pubic crest with associated thickening and heterogeneity of common rectus – adductor origin and adductor tendinopathy. (C) image of the contralateral normal side showing normal pubic crest and adductor origin A B Figs 11A and 11B. Images of the conjoint tendon in long (calipers) in a 23-year-old soccer player with ongoing, perplexing groin pain. (A) thickened conjoint tendon compared to the normal tendon in (B). The thickened conjoint tendon resulted in a sportsman’s hernia in this patient A B C D Pathology Any of these muscles are susceptible to strains, partial and full thickness tears, as has been described previously. Partial thickness tears in these muscles are often seen to affect the deeper portion of the muscle. A hypoechoic thickening will be visualised on ultrasound. Ilioinguinal nerve Figs 12A-12D. Images of the inguinal canal in cross section at rest (A), (C) and with the patient straining (B), (D). The patient in (A) and (B) has a sportsman’s hernia. The conjoint tendon is thickened and the canal remains in a horizontal plane at rest and with the patient straining. The inguinal canal (C) and (D) is normal showing the canal moving from a horizontal plane to a more vertical orientation The ilioinguinal nerve courses between the internal oblique and transverse abdominis muscles (fig 1), from the ventral ramus of the first lumbar nerve to the scrotum/labia [8]. It also supplies the medial thigh. It is therefore not unusual for the patient to complain of pain into the testicle and/or the proximal medial thigh over the adductor muscles. Ilioinguinal nerve entrapment is a good explanation for generalised, poorly targeted groin pain. 22 soundeffects Position the transducer transversely over the internal oblique and transverse abdominis muscles at the level of the ASIS and slide the probe obliquely towards the pubis. The nerve and artery will be seen running in the fascia between these two Ultrasound for athletic pubalgia A B peer review B A C D Figs 13A and 13B. Image of the inguinal ligament (cursors) at the level of the pubic tubercle. (A) Normal inguinal ligament. (B) The patient was point tender over the left pubic tubercle. The insertion of the inguinal ligament onto the pubic bone on the left is thickened with Figs 14A–14D. Images of the rectus abdominis muscle. Normal fluid overlying it. An avulsion fracture is seen deep to the ligament echogenicity seen in the transverse (A) and longitudinal (C) images. Increased echogenicity indicating a muscle strain in (B) and (D) muscles. Use colour Doppler to identify the artery adjacent to the nerve (fig 15). Pathology Ilioinguinal nerve entrapment Irritation of the ilioinguinal nerve may be a precursor to general groin syndromes. Repetitive sprinting, turning and kicking may excessively load and stretch the psoas and abdominal muscles causing irritation of the nerve [6]. The nerve appears thickened on ultrasound compared with the contralateral side (fig 15). It can be tender with probe pressure over the nerve. Conclusion When scanning a patient who presents with groin pain, the ultrasound examination should start with a hernia study. If no inguinal, femoral or spigelian hernia is identified, then the ultrasound should be extended to include the tendons, nerves and musculature around the groin, particularly around the pubic A tubercle. Correct diagnosis of common rectus abdominis – adductor tendinosis or ilioinguinal nerve entrapment, for example, assists greatly with treatment and can help to shorten the time out of sport and speed up recovery time. Acknowledgements 5. Edell D: Athletic Hernias. [Internet] 2009. Updated 24-10-2009; cited Jan 2013. Available from www.athleticadvisor.com /injuries/general_inj/athletic_hernias.htm 6. Mallac C. Groin Strain. Sports Injury Bulletin. [Internet] 2009. Updated 2009;cited Dec 2012. Available from www.lollylegs.com/images/groin.jpg I would like to thank Sally Bateman for her assistance with the anatomy diagram in this article. 7. MacMahon P, Hogan B, Shelley M, Eustace S, Kavanagh, E. Imaging of Groin Pain. Magnetic Resonance Imaging Clinics of North America. 2009;17(4). 1. Caudill P, Nyland J, Smith C, Yerasimides Y, Lach J. Sports hernias: a systematic literature review. Br J Sports Med. 2008;42:954–964. 8. Moore K, Dalley A. Clinically Oriented Anatomy – Fourth Edition. Lippincott, Williams and Wilkins; 1999. 2. Koulouris G. Imaging review of groin pain in elite athletes: an anatomic approach to imaging findings. AJR. 2008;191(4):962– 972. Available from www.ajronline.org /content/191/4/962.full 3. Robinson P, Bhat V, English B. Imaging in the assessment and management of athletic pubalgia. Seminars in Musculoskeletal Radiology. 2011;15(1). 4. Morelli V, Weaver V. Groin injuries and groin pain in athletes: part 1. Prim Care Clin Office Pract. 2005;32:163–83. B 9. Marshall N, Koulouris G. Traumatic Injuries of the Hip. Magnetic Resonance Imaging Clinics of North America. 2009 Nov;17(4). 10. Van Holsbeeck M, Introcaso J. Musculoskeletal Ultrasound Second Edition. Mosby; 2001. 11. Bianchi S, Martinoli C. Ultrasound of the Musculoskeletal System: Springer;2007. 12. Netter FH. 2006. Atlas of Human Anatomy. 4th edn. Philadelphia Saunders Elsevier. C Figs 15A-15C. Images of the ilioinguinal nerve in transverse between the internal oblique and transverse abdominus muscles. (A) Normal ilioinguinal nerve N with the artery A and vein V adjacent in colour. (B) shows thickened ilioinguinal nerve. (C) is a colour Doppler image showing colour in the adjacent blood vessel. Note the echogenic fibrosis surrounding the abnormal nerve in (B) and (C) ISSUE 2 2013 23