The foot is the hip!
Groin injuries are an increasing trend in the sporting world. As a group they are difficult to diagnose and treat due to the pathomechanics and the anatomy of the anterior hip joint. Common diagnoses for groin pain are femeroacetabular impingement, degenerative and acute labral tears. This may be due to dysplastic changes to the femoral head, over or under coverage of the head of femur (Ejnismann 2011).
But why are we getting these injuries? Why do they take so long to recover post surgery? My humble view is that we have not diagnosed the cause of the problem – the foot (potentially).
What is the labrum?
The labrum provides increased depth to the coxafemoral joint, therefore increasing its stability and congruity. The labrum is wider and thinner at the front and thicker in the posterior portion. It is rich in free nerve endings and sensory nerve endings (Groh 2009), therefore it is proprioceptively important to recognising changes in length and compression in the hip joint. The hip joint capsule attaches closely to the anterior and posterior labrum and provides stability to the joint along with a huge proprioceptive input.
The most common cause of stress to the labrum and capsule is with a combination of hip extension, abduction and external rotation. But what causes the stress to go to the hip?
We need to look at the kinetic chain and the point of contact with the ground, the foot. When we step, lunge, run, squat we create a load to our system through calcaneal eversion and pronation of the foot. This creates flexion, Adduction and internal rotation through the lower limb therefore eccentrically lengthening the powerful muscles at the back of the hip with relative internal rotation
But what would happen if the calcaneus did not evert due to motion restrictions in the system, injury or footwear that provides an external block?
If we look at a footballer with this restriction who has to quickly change direction off their right foot in a left rotational direction, the right foot will not go through pronation, therefore it will create a relative increase in external rotation at the tibia and femur causing a lengthening of the anterior hip capsule. In combination with this movement the trunk and pelvis will be quickly rotating to the left, increasing the external rotation, abduction and extension demand at the right hip. If the hip the body has not been trained into this end of range position, it will result in excessive stress to the labrum and capsule with the femoral head forced anteriorly and caudally resulting in a possible traction injury. We also need to look at the left leg, which will be moving in a lateral or rotational direction. The further we move in this direction the ability of the sub-talar joint to pronate decreases, this will cause increased external rotation on the left lower limb and hip joint and decreased shock absorption from the joints distal to the hip. If the right hip is restricted but able to handle the external rotation forces the extra stress will be placed on the left hip, resulting in possible traumatic injury.
If the player then has to undergo surgical intervention, we still need to address the underlying cause of the problem – lack of calcaneal eversion. This problem at the foot is very common in players with chronic ankle sprains, and may be partly due to the rigid heel cups that are prevelant in modern football boots and trainers.
If a client/patient is suffering with groin pain and symptoms we need to assess, train and rehabilitate in an upright position under load. If they are supine on a table they may show you all the motion in the world but when the joints are compressed and under-load, the body often shuts down. Momentum Physio work on a functionally based model for assessment, treatment and rehabilitation. Visit www.momentum-physio.co.uk for further information.
M, Groh, J Herrera (2009). A comprehensive review of hip labral tears
Curr Rev Musculoskelet Med. 2009 June; 2(2): 105–117.
Ejnisman,L. Philippon, MJ. Lertwanich,P (2011). Femoroacetabular impingement: the femoral side. Clin Sports med. 2011 Apr;30(2):369-77.
Gray, G (2005). FVDS, The Front Butt.