DDH 6 – 24 Months

DDH-6 to 24mo
Approach to DDH – 6 to 24 Months

The pathoanatomy is getting tougher here.
At this stage, abandon thoughts of using a Pavlik. These kids need a closed reduction and spica, or an open reduction and spica. Don�t be lulled into a false sense of security that you�ll be able to just get these reduced closed. Be prepared for the inability to get it reduced closed in the OR – ie. CONSENT FOR OPEN REDUCTION TOO !

Start with traction – this probably doesn�t reduce AVN, but it increases the chances of getting it closed.
Closed reduction of a L hip dislocation (osteotomies of pelvis or femur are rarely needed in this age group)
– one assistant to hold pelvis stable; the patient is supine
– right hand over the knee, left hand under the hip – apply traction
– then flex the hip up to 90, maintaining traction (so you�re lifting UP on the leg)
– then gentle abduction and external rotation once you�re up at 90 to bring the hip into joint.
– if you think you�re in, then assess for zone of safety. Determine at how little abduction he dislocates, then determine what the maximum abduction is. You want to avoid these extremes by about 15 degrees. So if he dislocates at 20, and maximum abduction is 50, his safe zone is only between 25 and 35 degrees (ie – a 10 degree safe zone). This is no good. Do an adductor release and check again. Basically, you want a wide zone of safety – 30 to 50 degrees. You want to make sure that you are not too close to the maximal abduction – risk AVN!

– then, .5 cc Isovue into the joint, injecting medially just under the adductor longus tendon (which is cut)
– look for a medial dye pool of less than 7 mm.
* if less than 7 mm, the kid gets a spica cast and a CT before discharge home
* if more than 7 mm, the kid gets an open reduction – medially if less than 1 year, anterolaterally if 1-2 years.

If you fuck up and forget consent for open reduction, back off, wake the kid up, talk to parents, then proceed later.

Comments on Open Reduction

Medial approach
– anterior to longus, posterior to pectineus.
– beware medial circumflex femoral artery which runs posterior to pectineus!
– you can get at the pulvinar, transverse acetabular ligament, ligamentum teres, and infolded labrum, but you cannot do anything to the capsule (hence, this approach should be reserved in the 1 year old or less who hasn�t had too much time to develop a hugely capacious capsule)

Anterolateral approach
– TFL/sartorius, then g.medius/rectus
– can do capsuloraphy too (T shaped capsulotomy, then pants-over-vest)

The key is to be prepared to go the whole nine yards in this age group – even though you may get it closed, you may have to run the entire gamut – you may NOT get it reduced closed. I fucked this up with Tredwell, by forgetting to consent the kid for an open reduction.