Navigating Hip Pain in Cerebral Palsy

In a continuing series on hip pain in Cerebral Palsy (CP), I wanted to share an interesting (an actually quite common) occurence when addressing the issue of hip pain in children with CP and other neurodevelomental disorders.  As most parents know, ANY sign or indications of pain / discomfort that comes from the hip immediately generate a swell of stress, anxiety, and worry about hip subluxation, hip dysplasia, and other common dysfunction of the hips.  All of these are common and generally manifest at some point along the line...but it is important to take the time to carefully address / assess the SOURCE of the pain so that it can be resolved as quickly as possible as well as provide better insight on how to proceed in the most efficient manner.

Most cases of hip dysfunction / pathology are diagnosed / confirmed with an x-ray, but it is important to (first and foremost) understand the role and limitations of an x-ray.  In a previous post on hip subluxation, I explore in detail the specific nuances of understanding the pediatric hip x-ray...which I recommend you read / re-read either before or after this post.  In that particular post, I outline a set of practical questions that should be asked in conjunction with the information acquired via the x-ray that will help in providing some clarityand ultimately help navigate what is generally a worrisome period of time.

The standard procedure when hip pain is suspected is to take an immediate x-ray.  While this is intuitive and indeed necessary, the subsequent analysis oftentimes gets limited to ONLY the hip joint itself...meaning that once the images are taken, almost all of the focus and magnified and intensified in one specific area.  The reality (in any healthy or pathological condition) is that pain can be manifest in a wide number of areas...and for a wide number of reasons.

Neutral (without internal rotation)

Internal Rotation

Lowenstein

The above images are a few quick "grabs" of some x-rays I reviewed a few weeks ago of a young girl who had recently begun experiencing pain in the hip area...manifesting during transfers and changes in position.  NB:  Not high quality images, but satisfactory for "pictures of pictures".  As "standard operating procedure", the x-rays were taken to examine the condition of the hip joint...and ultimately "confirm or discard" any specific issues with subluxation, dysplasia, or other common challenges.

Although my strategy going into any and all x-ray assessment is to look at the area in question, it is also (without question and without fail) to carefully examine and explore all of the articulations and bone mass captured in the image.  That is to say, not focusing on the hip joint itself and (whenever possible) look at the adjacent segment(s) above and below...all the way until you are "off the page". 

Before reading on, have a look at all of the images and take mental note of (if anything) strikes you or "jumps out" at you.

When I first saw these, there was a very immediate and explicit observation that literally leaped off the images...but, as a matter of practice, I followed through with a careful exploration of the bony information on the hip provided by these particular x-rays.  Without going into a lengthy and detailed assessment of these images, I will identify two main observations:

1.  The overall status of the hip / hip joint (as captured in these x-rays) looks relatively stable and, within the context of her particular pathology, look very good.  The variation between neutral, internal rotation, and Lowenstein is very small and negligible (perhaps even non-existent)...which generally suggests (with a certain level of confidence) that the joint and joint capsule are generally stable.

2.  There are some obvious asymmetries in the pelvis.

Asymmetric Pelvic Foramen

Healthy Pelvis

The pelvic foramen is essentially the "hole" that is formed by the joining of halves of the pelvis (which are connected at the front by the symphysis pubis and connect with the sacrum at the back).  A healthy pelvis will manifest a more symmetrical hole.  As demonstrated in the image below, the formal "shape" of the foramen is much more "circular or cylindrical".

 This was the first explicit indication of the potential genesis of pain...but the exploration continued.

Obturator Foramena

Note the shape and size of both Obturator Foramena (red arrows) 

Obturator Foramena (with abduction)

Of particular note and importance, when the legs are abducted, the overall shape (and therefore, position) of the obturator foramena (as well as the pelvic foramen, by the way) change considerably.  In other words, there is considerable disruption in structural integrity.  This visual information was then integrated into the previous set of symptoms and information gathered earlier.  To summarize:  

a) Significant pain that seems to come from the left hip (the "D" indicates the Right side).

b) Pain is manifest almost exclusively during movement and transfers.  More specifically with hip flexion.

c) Favored position (pain-free position) is neutral with no flexion or extension of the hip.

d) Underlying condition of high muscular tone (globally manifested).

Items C and D are of particular relevance when we consider the plethora of muscles and muscular attachments that enter / exit the hip...especially at the deepest levels. 

Deep Muscles of the Hip and Pelvis

The above illustration is an example some of the deep and intermediate muscles of the hip (left image is posterior, right image is anterior).  When we import the specific findings in the x-ray, the obvious conclusion is that the pelvis itself is manifesting a posterior tilt of the left side.  Although there are many potential "reasons" for this, the fundamental realities of CP are always at the nucleus:  

1.  ALL joints / articulations within the context of CP are weak...and therefore subject to excessive movement and displacement

2.  There is ALWAYS a certain level of muscular imbalance and disproportional levels of tension and weakness.  

RESULT:  Proportionally high levels of muscular tension and imbalance stress the various articulations and can potentially generate acute or chronic pain / dysfunction.  

In this particular case, it was concluded that the most likely genesis of the pain was this posterior tilt.  In essence, the acute bouts of pain during transfers and movement can be attributed to reflexatory muscular spasms of the deep hip / pelvic muscles.  If we refer back to the illustration above and simply abserve the number of muscles that originate or attach onto and around the pelvis (obturator foramen, symphysis pubis, etc..) it is not difficult to extrapolate the potential chance(s) for irregular stress and strain on the whole muscular system.  

With respect to the more practical "navigation" and management of pain, the specific objective becomes a tactical one:  

a) Manage levels of pain

b) Address the status and state of the muscles involved (those that play an immediate role in either reducing the amount of pelvic tilt and those that come under immediate threat of spasm). 

c) Implement a strategic mid-to-longterm plan to address the strength and integrity of the pelivs and pelvic joints (reduce the likelyhood of re-occurence and/or reduce the intensity/frequency/duration of pain).  

In summary, the main message is to (as best possible) engage in habits that encourage and facilitate a broad analysis of not only the area in question but the entire system.  In many cases, the formal "outlet" of pain (where it is felt) can have immediate and direct links but also indirect links to adjacent structures and architecture.