DDH 6 – 24 Months

Modern Study Review (AI-Generated)

High-Yield Summary

Developmental Dysplasia of the Hip (DDH) in children aged 6 to 24 months presents a more complex clinical challenge than in younger infants. At this stage, non-invasive methods like the Pavlik harness are generally ineffective, and treatment typically requires closed or open reduction followed by spica casting. Early and accurate reduction is critical to restore hip stability, optimize joint development, and minimize complications such as avascular necrosis (AVN).

Key Diagnostic Findings

Anatomy

• The hip joint is often dislocated or subluxated with soft tissue interposition (pulvinar, ligamentum teres, labrum).
• The acetabulum is shallow and may be dysplastic but can remodel if stable reduction is achieved.
• Medial circumflex femoral artery is at risk during medial surgical approaches.

Clinical Presentation

• Limited or asymmetric hip abduction.
• Limb length discrepancy or asymmetric thigh/gluteal folds.
• Positive Galeazzi sign or limited hip abduction on exam.

Imaging

• Ultrasound is less useful after 6 months due to ossification.
• Radiographs (AP pelvis) show femoral head displacement, acetabular index, and ossification center development.
• Arthrogram during reduction assesses soft tissue obstacles and joint congruity.
• Medial dye pool measurement on arthrogram:
• <7 mm suggests successful reduction.
• >7 mm indicates soft tissue interposition requiring open reduction.

Classification Systems

• No specific classification system dominates this age group; however, the International Hip Dysplasia Institute (IHDI) classification is commonly used for radiographic severity.
• The safe zone concept (Ramsey) guides reduction stability: the range of abduction angles where the hip remains reduced without risking AVN.

Current Gold Standard Treatment

Non-operative Indications and Treatment

• Generally limited to children under 6 months.
• In 6-24 months, non-operative treatment is rarely successful; Pavlik harness is contraindicated.

Operative Indications and Treatment

• Closed reduction with spica casting is first-line if achievable.
• Pre-reduction traction may improve success rates but does not reduce AVN risk.
• Open reduction is indicated if:
• Closed reduction fails.
• Medial dye pool >7 mm on arthrogram.
• Age >12 months with soft tissue obstacles.
• Surgical approaches:
• Medial approach (Ludloff) for children <12 months; limited capsular access, risk to medial circumflex artery.
• Anterolateral approach (Smith-Petersen) for children >12 months; allows capsulorrhaphy and better visualization.
• Adductor tenotomy may be performed to increase the safe zone of abduction.
• Post-reduction immobilization in a spica cast for 12 weeks is standard.

Modern Complications & Outcomes

Complications

Outcomes

• Early, stable reduction correlates with improved acetabular development and hip function.
• Closed reduction success rates vary but are higher with traction and adductor release.
• Open reduction outcomes are generally good when performed timely, with capsulorrhaphy improving stability.
• Long-term follow-up is essential to monitor for residual dysplasia and AVN.

Classic Clinical Notes

DDH 6 to 24 Months

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, 0.5 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 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 gluteus medius/rectus.
• Can do capsulorrhaphy 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 messed this up with Tredwell, by forgetting to consent the kid for an open reduction.

Last Updated on January 25, 2026 by orthonet