Thursday, 21 September 2017

Why is Adult Hip Dysplasia so Hard to Diagnose?

I've updated this post on my thoughts behind why Adult Hip Dysplasia seems so hard to diagnose.  Despite it being a relatively common condition in babies and young children, and it only takes an x-ray to identify it, an adult with hip problems can potentially be sent around the houses until they reach a diagnosis, and this can take many years (Nunley et al, 2011).

Below are some of my thoughts as to why this seems to happen:


Subtle early symptoms
The early symptoms accompanying dysplasia can seem quite mild, presenting as an insiduous onset recurring groin strain that by all accounts appears muscular in origin (Pun, 2016).  Clinicians also refer to what they call the "C-sign," when a patient cups their fingers around the lateral part of the hip to indicate something going on deep inside.  A patient might find this hard to describe or point to.

Symptoms related to activity
The early typical symptom pattern of this hip pathology is most commonly noticed during sport or activity (Nunley et al, 2011), so the symptoms might disappear when a patient takes a break from their sport.  With recurrance of the pain, they might decide to just stop altogether.  This could work fine for a while, or even a few years before the symptoms increase anyway.

Vague history
A young adult who has been treated for DDH as an infant may not put 2 and 2 together that this is related to their current hip pain.  Some of us are told that the "clicky hip" we had as a baby was successfully treated and 'fixed' with no need for follow-up.  A patient will also be relying on what their mother/care-giver has told them about it.  I wonder if the right questions are asked and clarified about this when a patient presents with hip or groin pain.

Hip Dysplasia in adults??
Some health practitioners might not be aware that DDH can occur in adulthood without an infant diagnosis.  More recent literature speaks of adolescent-onset dysplasia as well as residual childhood dysplasia presenting in adulthood.  It can reoccur even if treated successfully at birth. (Pun, 2016). 

The mix-up with impingement
Hip Dysplasia presents with very similar clinical signs and symptoms to Femoroacetabular Impingement, and these are hard to differentiate (Nunley et al, 2011).  For example, in both DDH and FAI, pain will occur when flexing and internally rotating the hip.  However, with an impinged hip this is due to the femoral neck hitting against the acetabulum, whereas in DDH this is due to it hitting a sore labrum.  It is not unheard of for Dysplasia to be misdiagnosed as Impingement.  A clearer diagnostic picture can be formed when subjective and clinical findings are backed up with x-rays interpreted by a hip specialist for a full diagnostic picture.

Not feeling the need to diagnose
If the symptoms present seem concurrent with a soft tissue injury, and physiotherapy and strengthening techniques are working for the time being, then a clinician might not feel the need to find a definitive diagnosis.

Awareness of other options
Not all health professionals are aware that Pelvic Osteotomy such as PAO or TPO surgery exists for the treatment of adult hip dysplasia.  This is a surgery which re-shapes the acetabulum in order to delay OA in a dysplastic hip and therefore delay hip replacement until a later age, but is more likely to be successful before OA has developed in the joint.

Not knowing when to refer
There can be difficulty knowing at what point a patient with hip or labral symptoms should be referred on to a specialist hip consultant.  Groh (2009) suggests that there should be 12 weeks of physio input and if this hasn't worked then refer on.

If you think that a patient has an underlying abnormal hip pathology such as Dysplasia or Impingement, or have a strong suspicion they do based on your subjective and clinical findings, then the referral should happen promptly.  For example, they might know that they've had it from birth, or they might have had an x-ray and diagnosis from a non-specialist in orthopaedics.  Obviously you don't need to send them off in an ambulance with the sirens wailing, but a timely definitive diagnosis is pretty important (for more on this, see my related post: Why the Rush?)

Lack of access to an experienced consultant in hip dysplasia
A consultant who specialises in young adult hip pathologies and who treats a large volume of cases is worth their weight in gold, but they are few and far between and dotted around the country.  Those who aren't as specialised or who don't treat as many cases may have a harder time interpreting the findings from x-rays and clinical presentation (Malviya et al, 2016), or may be reluctant to operate on hips with less severe dysplasia due to uncertainty of outcomes.  There are stories of dysplasia just not being picked up by orthopaedics even with an x-ray.  These factors may cause confusion for patients and their referring clinicians.

With all the above being said, it is important to realise that there are positive stories also, of symptoms being recognised, referrals being made to the right clinicians, and favourable outcomes from surgeries.  There are undoubtedly many highly skilled and astute clinicians out there.  I'm sure I am one of many hipsters who is, at times, guilty of throwing my hands up in the air and exclaiming "Aaah, nobody knows anything about this condition!"  And whilst that is obviously said out of exasperation, the above points need to be taken note of.

See also: Why the Rush?

Info taken from:

Groh, M. M. & Herrera, J. (2009), A comprehensive review of hip labral tears, Current Reviews in Musculoskeletal Medicine. 2 (2).   doi: 10.1007/s12178-009-9052-9

Malviya, A., Raza, A. & Witt, J. D. (2016) Reliability in the diagnosis of femoroacetabular impingement and dysplasia among hip surgeons: role of surgeon volume and experience, Hip International, Vol. 26 (3)

Nunley, R. M., Prather, H., Hunt, D., Schoenecker, P. L. & Clohisy, J. C. (2011) Clinical Presentation of Symptomatic Acetabular Dysplasia in Skeletally Mature Patients, The Journal of Bone & Joint Surgery. 93-A (2) 

Pun, S. (2016) Hip Dysplasia in the Young Adult caused by residual childhood & adolescent-onset dysplasia, Current Rev Musculoskeletal Medicine, Vol. 9 (4)

West, S., & Witt, J. (2011) Bilateral Developmental Dysplasia of the Hips, British Medical Journal. 342 doi doi: http://dx.doi.org/10.1136/bmj.d2152