Whilst the sun shines on Lee Valley, the rain pours down on Los Angeles - sorry guys! Meanwhile, those athletes that remain in the Pleasure Dome are enjoying an empty track & throwing area.
Following on from my last blog discussing the differential diagnosis of sporting hip & groin pain & the influence that adductor pathology can have on the area, today I will discuss the part that abdominal pathology can play. My thoughts are shaped by James Moore & Mark Young's "Sporting Hip & Groin" workshop, Per Holmich, Andry Vleeming, Diane Lee, Eoin Falvey & time spent in Germany with Dr Ulrike Muschawek at the Hernien Zentrum.
ABDOMINAL PATHOLOGY
The second part of the triumvirate of influencing factors in hip & groin pain is the abdominal muscle group.
The anterolateral abdominal wall comprises the obliquus externus abdominus (external obliques), the obliquus internus abdominus (internal obliques & the transversus abdominus. A fascial layer, called the transversalis fascia then lies between the posterior surface of the transversus abdominus & the peritoneum. The external obliques are the lateral abdominals, whilst the internal obliques have a much larger cross sectional area & the wide pennation reflect the influence of the muscle.
The aponeurotic fibres of these three muscles (non-contractile components) then fuse at the front to form a sheath, which blends into the rectus abdominus muscle lying ventrally.
It is also important to consider the fibro-osseus attachments of these muscles for the simple reason that they are so extensive, attaching to the rib cage, spine & pelvis.
Given the close relationship of these structures, the integrity of the inguinal canal must be established. The roof of the canal is formed by the internal oblique & the transversus abdominus (the only contractile components of the canal), whilst the floor comprises the inguinal ligament & lacunar ligament. Anteriorly the external & internal oblique aponeuroses form a wall, whilst the posterior wall is provided by the transversalis fascia & conjoint tendon.
The influence of the non-contractile tissues must be considered in rehabilitation & injury prevention by ensuring that in addition to muscle strengthening, ligament & tendon loading must be addressed. The influence of the internal obliques must be considered by ensuring that these are loaded daily too.
Therefore, groin pain that is influenced by abdominal pathology can be caused by:
- Acute tears or musculotendinous junction disruption of the external oblique (common in American Football when the quarterback is sacked)
- True hernia
- Sportsman’s Groin (includes fascial strain, compartment pressure, “Gilmore’s Groin”, posterior abdominal wall disruption, nerve entrapment or irritation, inguinal ligament neuralgia, or incipient hernia)
- Iliopsoas related pain
- Rectus abdominus related pain
External oblique tears or MTJ disruptions will bleed into the superficial pocket & the bruising will be delineated by the inguinal ligament
True hernias are direct invaginations of the intestines through the abdominal wall & are characterised by swelling or pain in the Hasselbach’s triangle, with a reporting of a “deep, dragging pain”. If it is a true hernia, you should refer to a specialist to decide intervention
In males, the inguinal canal is stretched at puberty & contributes to the inherent weakness, which is reflected in the greater proportion of “Sportsman’s Groin” presentations in males versus females.
“Sportsmans Groin” is an umbrella term that covers an array of conditions affecting either fascia, posterior abdominal wall, nerve or ligamentous structures. James Moore & Mark Young define this as “a pain or lesion superior &/or lateral to the superior pubic tubercle as a result of laxity, thinning or deficit in the lower abdominal region with or without bulging of the posterior abdominal wall.”
The athlete will often report that they are missing the top-end performance, with difficulty performing repeat bouts of activity, which will be due to tissue recovery factors. As the symptoms persist, the pain will come on sooner, last longer & increase in intensity. There may be pain on cough/sneeze, weight transfer after activity, accelerating & rotational activity.
The most common sports predisposing to the presentation are soccer, rugby, cricket, weight lifting & endurance running due to either the accelerations, changes of direction, high tensile loads & force production or repetitive microtrauma.
i)
Fascial strains & tears are characterised by a reporting of pain on
contraction but without a loss of power or function. Strains or tears will predominantly affect
the external oblique fascia (including the external inguinal ring). Repetitive fascial tearing will lead to
scarring, which can decrease the sliding of the fascial & muscle layers on
each other & result in pain on stretch & a reduced range of movement. This can also lead to nerve entrapments &
ischaemia.
Given that the border nerves all pass through the inguinal ring, they can
produce chronic groin pain, which will be painful on loading but often worse
after rest or activity. Nerves can infiltrate the inguinal ligament &
external oblique aponeurosis, thus leading to mechanical irritation.
ii)
If the inguinal nerve becomes entrapped, this can refer down into the
groin area. It is important to consider
that sustained irritation can lead to hyper-sensitivity of the tissue &
altered motor function, whilst surrounding tissues can be affected by collagen
degeneration & tropedema.
iii) Gilmores Groin isn’t a true hernia but the term describes a thinning or disruption of the posterior abdominal wall, which can involve a tear in the external oblique aponeurosis, a tear in the conjoined tendon or a dehiscence between the conjoined tendon & inguinal ligament.
In 30% of
cases, there will be an acute mechanism of injury, which will often involve an
over-stretching activity in abduction & external rotation. In the more chronic presentations, the
symptoms will present as pain & stiffness after exercise, which can be exacerbated
on resisted adduction or a half sit –up.
This then results in a reduced intra-abdominal pressure, which affects the
ability to load bear.
iv)
Inguinal
ligament neuralgia can precipitate pain on palpation of the ligament,
specifically at the insertion into the pubic tubercle caused by scarring in
response to either an acute or chronic disruption. The pain will be unilateral & may present
on loading.
Iliopsoas related pathology may present as either pain or weakness on loading. Holmich documents three tests for groin pain influenced by iliopsoas related pathology in his 2004 study evaluating the intra- & inter-observer reliability of clinical examinations in athletic groin pain. These are palpation, functional testing in supine with resistance provided against hip flexion & resisted testing in a Modified Thomas Test position.
Holmich would argue that all three tests have to result in positive pain provocation to indicate an iliopsoas-related problem. However, what is notable is that, whilst the authors functionally evaluated adductor muscle, iliopsoas muscle & abdominal muscle function, the hip was not included in the assessment process, which given the influence that the hip joint can play in groin pain presentation, might suggest that a complete differential diagnosis was not conducted. Furthermore, no imaging studies were included in the battery of tests, so it would be inaccurate to eliminate an underlying hip dysfunction.
Rectus abdominus pathology may present
as either a myofascial injury or a tendinopathy. Myofascial injuries will be demonstrated
clearly on MRI & asymmetry that can be palpated in relation to density discrepancies
in the muscle, will be clearly displayed on such imaging.
Falvey, Franklyn-Miller & McCrory (2009) suggest that rectus abdominus pathology will be localised to the insertion at the pubic tubercle, with pain presenting superior to the Groin Triangle upon which their model is based & as such they deem such pain as being a very "clear-cut diagnosis". The presentation may be primary in origin or secondary to pubic overload originating from adductor or iliopsoas pathology.
ABDOMINAL TESTING
External oblique injuries will be highlighted on a rotational provocation test, where the athlete lies in a crook position, with their arms reaching out to the side, perpendicular to the plinth. Rotational resistance should then be applied in both directions on both sides.
Rectus abdominus injuries with be
apparent on sit-ups with first bent, then straightened knees, first without
resistance, then with resistance applied to the chest & knees of the
athlete.
Intra abdominal pressure can then be increased to detect a “Sportsmans Groin” by performing a resisted bilateral straight leg raise. If the action is weak & painful, this will indicate muscle tissue damage, whilst a stronger contraction that is painful will indicate a neural, fascial or tendon component. To get an objective measure the maximum numbers of leg lowers & supine wide leg scissors, which will focus the load on the adductors, can be recorded.
Posturally, the athlete will
demonstrate a lordotic posture, with a rounded pot belly, whilst a reduced hip
range of movement will not prevent the subject being able to get their hands to
the floor
A cough impulse will indicate a potential posterior abdominal wall disruption
Iliopsoas pain & weakness
will be detected using the tests mentioned above as described by Holmich.
Imaging studies should be guided by which structures the physical examination raises suspicion of & may include x-ray, MRI, ultrasound Doppler or herniography.
As ever, I would welcome any thoughts & experiences that you can offer on the subject in the "Comments" area below, whilst recommending reading any of the texts, papers or registering for the courses led by the clinicians that have influenced me in this area.
