"Rare"

"He had never seen so many cripples all gathered together in one place outside of a hospital.  It was easy to see that a large number of the cripples were cases of congenital dislocation of the hip, some bilateral, some unilateral.  Some crawled on their hands and knees, some hopped about like clowns, others waddled like ducks.  All accepted with typical stoicism their misfortune as life's lot.  They knew no different..."

The above is an alarming extract from an account of one person's visit to some Canadian Indians in Manitoba in 1940.  This people group had not been treated for what was then called "Congenital Hip Dislocation" and so provided a perfect opportunity to witness the natural progression of the condition.  Other past accounts of Saskatchewan Indians reveal how their swaddling techniques contributed to forms of hip dysplasia, and again, show how this affected their mobility over time (although I think I might not use the word 'cripple' these days!).

I've heard people use the word "rare" when speaking of Hip Dysplasia, and it led me to wonder what the actual epidemology of the condition is.  So I went on the hunt for some numbers, and this is what I found:

1 in 6 newborns will have an element of hip instability

2-3 in every 1,000 infants will require treatment

Roughly, hip dislocations occur in 0.8% of the newborn population

7-8% of ALL newborn females have dysplasia (a shallow acetabulum)

So, more or less,
for every 1 dislocation discovered by ultrasound, there are 10 cases of dysplasia

80% of DDH cases occur in female patients

In adults 90% of patients with labral pathology have some form of underlying hip abnormality

80% of hip replacements are due to some form of biomechanical abnormality, in women the most common abnormality is Hip Dysplasia

  Hip Dysplasia accounts for approx. 70% of all cases of hip arthritis in women and
approx. 10% in men

Studies find the incidence of hip dysplasia at 0.5 - 5% of the general population.  That's at least 1 in every 200

The median age when hip dysplasia was found was 7 years-old according to one study 

Over 50% of people with hip dysplasia have a positive family history of the condition

48% of THRs under 50 are due to OA from hip dysplasia

Hip Dysplasia accounted for 26% of THRs under 40 years of age according to the Norwegian Arthroplasty register

92% of young adult patients (under 50) undergoing THR due to underlying hip dysplasia had no reported hip instability in the newborn period

Hip Dysplasia has a higher probability of progressing to end-stage OA or THR at 10 & 20 year follow-up compared with Femoro-Acetabular Impingement

Fewer hips treated with Pelvic Osteotomy go on to develop end-stage OA at
18 - 20 year follow-up

Some of these figures are taken from Germany, Switzerland and parts of Denmark, where ultrasound scanning for ALL newborns is a legal requirement before they leave the hospital.

Now, if you're speculating that some of those figures don't match up, note that if a case of Hip Dysplasia is very mild, it won't even be picked up at birth, and may not even trouble a person for the majority of their life, but could still be the cause of what we consider to be "Primary Osteoarthritis."  The other 30% of hip OA in women and the 90% in men are said to be due to undiagnosed SUFE or Legg-Calve-Perthes disease, which are other paediatric hip conditions - often also inadequately investigated.

Also remember that treatment of infant Hip Dysplasia, particularly in the UK seems to be much of a postcode lottery.  For some their dysplasia is missed altogether.  Some are treated and said to be resolved, with no long term follow-up.  For some it is 'discovered' in adulthood with no previous pain or mobility problems.  So I imagine putting together accurate figures for the time being is a tricky business.

In a study of Adult Hip Dysplasia:

It took between 5 months - 29 years for patients to receive an accurate diagnosis

Visiting up to 11 health professionals before the diagnosis was made

That's an average of 6 years and 3 health professionals

Wow, that's bad.  I mean, it is amazing the leaps and bounds that are constantly taken in medicine.  The very fact that osteotomy surgeries exist is remarkable, and improved detection and treatment for infants found to have DDH goes towards reducing the affliction in later life altogether.  I read another quote from the above article by Robert B. Salter 

"Early diagnosis and early treatment of congential dislocation of the hip are now possible.  The next great challenge is the prevention of this serious and disabling condition."

I thought, 'Yes, Robert. You echo my sentiments exactly.'  Then I read the date when they were made: 1967.

1967?!?!

How on earth is it that we are still saying this now, 50 years later?!  It is still missed, poorly treated or neglected in so many.  Story after story of individuals with hip pain not being listened to, struggling to gain a diagnosis, or quite frankly the correct advice and treatment from health professionals when a diagnosis is found.

I'm thinking of the lovely lady on my internet group who is on a cocktail of painkillers, but some days cannot take her son to school because she is struggling to walk outside of the house.  A friend of mine who's had unsuccessful treatment and is now having to repeatedly take time off work due to pain and mobility issues.  The ram-packed clinics of specialist hip consultants making it hard for someone in her position to get a timely appointment.  Meanwhile the joint damage creeps in, and time is of the essence if joint preservation surgery is to be considered.

I don't know much about statistics and whether these numbers hold much value as I have little experience in practice yet, but I do know that, rare or not, this is a distressing and disabling enough condition to be taken note of.



Info taken from: 

Bedi, A., Kelly, B. T. & Khanduja, V. (2013) Arthroscopic Hip Preservation Surgery: Current Concepts and Perspective, The Bone & Joint Journal. 95 -B (1) 

Engesaeter, I., Lehmann, T., Laborie, L. B., Lie, S. A., Rosendahl, K. & Engasaeter, L. B. (2011) Total Hip Replacement in young adults with hip dysplasia.  Acta Orthopaedica, 82 (2). 149-154

International Hip Dysplasia Institute (2016) Causes of Hip Dysplasia. Retrieved from
http://hipdysplasia.org/developmental-dysplasia-of-the-hip/causes-of-ddh/ 

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) 

Orthopaedic Research UK (n.d.)  DDH Charity: The new hip charity on the block. Retrieved from http://www.oruk.org/news-and-events/news-stories/k9v463ur4u.html 

Price, C. T. & Ramo, B. A. (2012) Prevention of Hip Dysplasia in Children and Adults, The Orthopaedic Clinics of North America, 43 (3) 

Pun, S. (2016) Hip Dysplasia in the Young Adult caused by residual childhood and adolescent-onset dysplasia. Current Reviews in Musculoskeletal Medicine 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

Wyles, C. C., Heidenreich, M. J., Jeng, J., Larson, D. R., Trousdale, R. T. & Sierra, R. J. (2017) The John Charnley Award: Redifining the Natural History of Osteoarthritis in Patients with Hip Dysplasia & Impingement. Clinical Orthopaedics & Related Research, 475. 336-350