Definition

‘Sports hernia’ is a condition of chronic exercise-related supra-inguinal groin pain which is associated with an incipient direct bulge of the inguinal wall whenever the abdominal muscles contract forcefully. This limits athletic performance and can be a ‘career-ending’ injury.

Synonyms

Sportsman’s hernia, Athletic hernia, Gilmore’s groin.

Symptoms

Sports that are most often affected involve kicking and/or rapid acceleration with an accompanying sudden change in direction (e.g. soccer, rugby, AFL, ice hockey, martial arts). The pain develops during exercise, is generally unilateral but occasionally bilateral, and is typically located in the supra-inguinal portion of lower abdomen lateral to rectus abdominis, sometimes radiating to the testis (Fig 1, solid arrows). Importantly, it does not reach the pelvic midline, but can often radiate into the medial thigh along the path of adductor longus (Fig 1, dotted arrows). Sports hernia pain is often aggravated by sudden acceleration, twisting and turning, cutting and kicking, coughing and/or sneezing, and sit-ups. The pain generally persists after a game, with accompanying stiffness and difficulty getting out of bed the following day. In most cases, the initial onset is insidious. However, in about one third of cases, the patient recalls a sudden ‘tearing’ sensation at the time of initial symptom onset [1]. Despite any period of rest or lay-off, Sports hernia pain returns immediately and with full force upon resumption of sport.



Fig 1. Location of Sports hernia pain

Physical findings

The overwhelming majority of patients are young adult males. Objective physical examination findings are typically sparse. A palpable cough impulse is either weak or absent. A subtle bulge in skin surface contour can occasionally be seen over the affected inguinal region when observed from above with the patient standing. Pain may be evoked with a resisted abdominal ‘crunch’ and tenderness elicited most commonly over the conjoint tendon immediately superomedial to pubic tubercle. Many patients also exhibit tenderness over the ipsilateral adductor longus origin and/or have a positive adductor ‘squeeze’ test in bent knee position (pain and inhibition when asked to squeeze the legs together against resistance).

Anatomy

The anatomy of the conjoint tendon is a key to understanding ‘Sports hernia’. The conjoint tendon is a condensation of tissue that forms along the lateral edge of lower rectus sheath from the fused internal oblique and transversus abdominis tendons (noting that these tendons can occasionally remain entirely separate). Although the lateral abdominal muscles are the dominant stressors of conjoint tendon, this structure also absorbs forces via connection with the adjacent rectus abdominis tendon and the pubic plate distally. On imaging, it is noteworthy that (i) the resting tendon is usually more vertical than horizontal in orientation, (ii) the distal tendon is located posterior to overlying pyramidalis muscle, and (iii) the tendon passes across the approximate junction between middle & outer 3rds of pubic crest:

Conjoint Anatomy 1. PD-weighted coronal MR images obtained in the plane of the lower rectus abdominis muscle show the location of conjoint tendon (arrowheads) and its relationship to adjacent structures (orientating sagittal image on the left shows the exact plane and location of the coronal images). Note the relatively vertical orientation of the tendon, positioned immediately superomedial to the inguinal canal & contained spermatic cord (SC). In the coronal plane, the conjoint tendon passes immediately deep to the inferolateral corner of pyramidalis muscle (better appreciated on Fig Conjoint Anatomy 2) and is confluent with the adjacent rectus abdominis tendon comprised of both central (solid arrows) and lateral (dashed arrows) slips that are typically multiple in number with interspersed fat. AL = Adductor longus, RA = rectus abdominis, P = pyramidalis.



Conjoint Anatomy 2. PD-weighted coronal-oblique MR images obtained in the plane of the pubic bone further illustrate the location and relationships of conjoint tendon (orientating sagittal image on the left shows the exact plane and location of the coronal-oblique images). Images on the top row show the tendon forming at the lateral margin of rectus abdominis as the internal oblique (IO) and transversus abdominis (TA) tendons merge. Middle row images show the tendon located at the medial margin of inguinal canal & contained spermatic cord (SC). Bottom row images show the tendon passing immediately deep to the inferolateral corner of pyramidalis muscle and across the approximate junction between middle and outer 3rds of pubic crest. Note lateral slips (dashed white arrows) and central slips (dashed yellow arrows) of adjacent rectus abdominis tendon with interspersed fat. RA = rectus abdominis, P = pyramidalis, AL = adductor longus.

Functionally, the conjoint tendon is integral to the mechanism that normally protects against a direct hernia arising through the weak posterior inguinal wall. At rest, the inguinal canal has a curved ‘superior wall’ created by the inferior margins of the internal oblique and transversus abdominis muscles. When these muscles contract, the superior inguinal wall normally straightens, moving inferiorly like a ‘shutter’ to narrow the craniocaudal diameter of the inguinal canal (Video 2). This mechanism requires both an intact conjoint tendon and good muscle function.

Pathology

At operation there is a subjective finding of weak (lax or incompetent) posterior inguinal wall [2,3,5]. In a minority of cases there is an objective surgical finding of non-acute conjoint tendon tear or external oblique aponeurosis tear producing dilatation of the superficial inguinal ring [1,2]. In the author’s experience, most cases show localised tender hypoechoic thickening of the conjoint tendon at or just above the pubic crest on real-time ultrasound interrogation (Fig 2). Occasionally, the conjoint tendon may also show a thin well-defined hypoechoic cleft of intrasubstance tear (Fig 3), although care must be taken not to confuse this with the normal conjoint tendon variant of non-fused internal oblique & transversus abdominis components. Many patients demonstrate an associated confluent tendonopathy (Fig 4) or tear (Fig 5) at the ipsilateral adductor longus origin. Although Sports hernia can occur as an isolated injury, the majority of cases exhibit features of underlying pubic dysfunction or instability.

Fig 2. Ultrasound of conjoint ‘tendonitis’. The abnormal RIGHT conjoint tendon was markedly tender over a focus of hypoechoic swelling (arrow). Normal LEFT conjoint tendon indicated by arrowhead. These long-axis images were acquired using a broad-band 9-4 MHz linear array transducer with the patient’s head to the viewer’s left. P = pubic crest.

Fig 3. Ultrasound of conjoint tendon tear. The abnormal RIGHT conjoint tendon was mildly swollen and markedly tender over a well-defined short hypoechoic cleft of complicating central intrasubstance split tear (arrow). Normal LEFT conjoint tendon indicated by arrowhead. These long-axis images of each conjoint tendon were acquired with a broad-band 13-5 MHz linear array transducer with the patient’s head to the viewer’s left. P = pubic crest.

Fig 4. Sports hernia patient with associated right adductor longus origin ‘tendonitis’. The abnormal RIGHT adductor longus origin was tender over a zone of hypoechoic thickening that most conspicuously involved the more superficial fibres (arrows) and could be seen to merge superiorly with the conjoint insertion. A comparison view of the LEFT adductor longus origin shows normal tendon contour and echotexture (arrowheads) at a corresponding location. These long-axis images were acquired with a broad-band 13-5 MHz linear array transducer with the patient’s head to the viewer’s left. Dotted arrow indicates a further small area of accentuated tendon hypoechogenicity in this case that either reflects an additional component of focally more severe central tendinosis or a complicating intrasubstance tear.

Fig 5. Concomitant adductor longus origin and conjoint tendon injury. Transverse (A) and sagittal (B) ultrasound images show an acute tear which simultaneously involves the abdominal and adductor longus tendons. The tear is appreciated as a hypoechoic line (arrows) that involves the adductor longus origin and extends superiorly as an intrasubstance laminar split into a swollen distal conjoint tendon (arrowheads). The conjoint tendon tear in this case probably also involves the adjacent lateral fibres of rectus abdominis tendon. Adductor longus tendon surface contours are indicated by white dots. Other labelled structures include pyramidalis muscle (p), rectus abdominis tendon (r), superior pubic ligament (s), pubic crest (c) and symphysis pubis (sp). Scans were acquired with a broad-band 12-5 MHz linear array transducer.

Imaging

There are two key imaging features that must be simultaneously present to support a clinical diagnosis of Sports hernia. The first is an incipient direct bulge of the posterior inguinal wall when forcefully contracting the abdominal muscles. This is best seen with real-time ultrasound as a dynamic phenomenon observed during a partial ‘sit-up’ manoeuvre (Video 1 contrasted with Video 2), but can also be appreciated with multi-slice CT (Fig 6), dynamic MRI (Fig 7) and contrast peritoneography [6,7,8]. In marked cases, the bulging posterior inguinal wall can also be evident at rest. The second key imaging feature of Sports hernia is an abnormal conjoint tendon. Conjoint ‘tendonitis’ and/or conjoint tendon tears are best imaged with ultrasound (Figs 2 & 3), as MRI detects tendonopathy (Fig 8) with much lower sensitivity and ultrasound has the added advantage of being able to correlate tenderness. Even so, the grayscale sonographic changes of low-grade conjoint ‘tendonitis’ can occasionally be subtle, with the abnormal tendon then appreciated only on the basis of mild thickening with associated tenderness. Ultrasound also has the significant limitation of being a highly operator-dependent test, requiring an experienced and careful operator with a clear understanding of relatively complex anatomy. Other imaging findings can include: (a) features of accompanying adductor longus ‘tendonitis’ or tear (Fig 4), and (b) additional features of underlying pubic dysfunction or instability such as pubic bone stress reaction described as ‘osteitis’.



Video 1. Incipient direct bulge of the posterior inguinal wall on contraction of the internal oblique & transversus abdominis muscles (e.g. during a shallow sit-up or when asked to ‘tense’ the abdominal muscles) indicates either incompetence of the conjoint tendon or dysfunction of the IO + TA muscles. This can have a variety of causes but, when found together with a demonstrably abnormal conjoint tendon in a clinical context of chronic exercise-related supra-inguinal groin pain, helps to confirm a diagnosis of Sports hernia. In the example shown here, the superimposed red line indicates the posterior inguinal wall. This is initially concave with the abdominal wall at rest, but then on straining during a partial sit-up manoeuvre displaces anteriorly as a convex bulge (yellow arrow). Video was acquired with a broad-band 13-5 MHz linear array transducer orientated in a sagittal-oblique plane to display the inguinal canal in short-axis with the patient’s head to the viewer’s left. Comparison can be made with the normal pattern of inguinal wall motion shown in Video 2 below. Animated overlay courtesy of Missing Mouse Design [missingmouse.com].



Video 2. Normal motion of the posterior inguinal wall. When the conjoint tendon becomes taught as the internal oblique & transversus abdominis muscles contract, the superior ‘wall’ of the inguinal canal normally moves inferiorly as a ‘shutter’ to protect against herniation of abdominal contents directly through the vulnerable transversalis fascia of posterior inguinal wall. Video shown here was acquired with a broad-band 13-5 MHz linear array transducer orientated in a sagittal-oblique plane to display the inguinal canal in short-axis with the patient’s head to the viewer’s left. Normal shutter motion is shown as the patient contracts the abdominal muscles during a partial ‘sit-up’ manoeuvre: the superior margin of the inguinal canal, appreciated as an increasingly abrupt angulation in wall contour, can be seen to move in an inferior direction. Note the posterior wall of the inguinal canal (indicated by the central segment of the red line) normally shows progressive tilt but remains straight (yellow arrow). Animated overlay courtesy of Missing Mouse Design [missingmouse.com].

Fig 6. CT of bilateral incipient direct inguinal hernia. Non-contrast axial CT images show normal posterior inguinal wall contours at rest (arrowheads) but abnormal anterior bulge of both posterior inguinal walls on straining (arrows).

Fig 7. MRI of incipient direct LEFT inguinal hernia. Axial MR images shown here have been obtained at the same level through the mid-portion of each inguinal canal both at rest (PD-weighted image using fast spin-echo technique) and during a partial ‘sit-up’ manoeuvre (T1-weighted image using VIBE technique). Normal posterior inguinal wall contours are present bilaterally at rest, but abnormal anterior bulge of the LEFT posterior inguinal wall is appreciated on straining (arrow).

Fig 8. MRI of LEFT conjoint tendonosis. Axial fat-suppressed PD-weighted MR images shown here demonstrate subtle localised signal hyperintensity involving the LEFT conjoint tendon at and immediately superior to pubic crest (arrows).

Diagnosis

The existence, significance and diagnosis of Sports hernia are all controversial. Reasons for this include the clinically occult (impalpable) nature of the condition, the subjectivity of any posterior inguinal wall ‘laxity’ reported at operation, the seeming improbability of minor direct hernial bulge producing significant symptoms, the high background incidence of asymptomatic inguinal wall bulge in both general and sporting populations [6,7,8,9], and the frequent confounding effect of underlying pubic dysfunction or instability which may produce concomitant symptomatic changes at both the symphysis pubis and para-symphyseal tendons (conjoint insertions & adductor origins) either unilaterally or bilaterally.

In the author’s view, two important points can be made: (1) cases of chronic athletic groin pain often include a definite abdominal (i.e. supra-inguinal) component that is located well lateral to the midline, is clearly provoked by manoeuvres that involve contraction of the lateral abdominal muscles, correlates consistently with conjoint tendon abnormality on real-time ultrasound examination, and is without doubt a real entity that has been called by others the “Sports hernia”; and (2) most cases of Sports hernia occur concurrently with, and are likely a consequence of, acquired pubic dysfunction or instability. The most likely generator of the supra-inguinal component of pain in Sports hernia patients is the abnormal and frequently tender conjoint tendon.

The clinical diagnosis of Sports hernia is difficult and requires both a careful history and thorough work-up to determine the relative contribution of any co-existent pathology about the pelvis & hip more generally (particularly findings that might suggest a broader aetiological context of pubic dysfunction or instability). In our clinic, the investigation of chronic athletic groin pain routinely involves: (1) functional (weight-bearing) plain radiographs of the pelvis, including flamingo views, to assess pelvic stability and screen for hip pathology, bone stress and soft tissue calcifications; (2) ultrasound to assess the conjoint tendons, dynamically assess the straining inguinal canal, and identify specific anatomic sites of tenderness; and (3) MRI to assess the symphysis pubis and supporting ligaments, pubic bones and pubic apophyses, adductor origins, rectus abdominis insertions and pyramidalis muscles (also providing a limited assessment of the hip joints, iliopsoas structures and obturator nerves).

At a minimum, the clinical diagnosis of Sports hernia requires 3 essential elements: (1) a supra-inguinal component of chronic exercise-related groin pain; (2) an abnormal conjoint tendon on imaging and/or physical examination; and (3) a dynamic finding of incipient direct bulge of the posterior inguinal wall when forcefully contracting the abdominal muscles.

Treatment

Surgical repair is the definitive treatment for Sports hernia, and has a reported satisfaction rate of more than 90% [1,3,5]. However, as some cases of supra-inguinal pain conceivably relate to a potentially reversible condition of conjoint ‘tendonitis’, initial management is preferably conservative with a 3 – 6 months trial of physical therapy targeted to core strength and pelvic stability. If there is no improvement, the surgical options are either (1) repair of the conjoint tendon and posterior inguinal wall using an open technique that avoids mesh [10], or (2) a laparoscopic inguinal hernia repair that utilises bilateral mesh which importantly overlaps in the midline to effectively brace the symphysis pubis [11]. If the clinical presentation includes a component of chronic adductor longus origin ‘tendonitis’, many surgeons will also perform an adductor tenotomy at the same time. Tenotomy can assist with pain relief by de-tensioning the affected (predominantly superficial) fibres of adductor longus but, in the author’s view, may be counterproductive in the longer term if this exacerbates any underlying pubic dysfunction or instability by further weakening the normal dynamic cross-brace mechanism that stabilises the symphysis pubis. Surgery is followed by an additional 3 months post-operative physiotherapy.

Acknowledgement

The author thanks Dr Ken Crichton, Sports Physician, North Sydney Sports Medicine Centre, for his expert clinical advice.

References