DDH Open Reduction (Medial & Anterior Approaches)

Indication. Open reduction is required when a concentric, stable reduction of the dislocated hip cannot be achieved or maintained by non-operative (closed) means, or when the child presents too late for those methods to succeed. Principal indications - Failed Pavlik harness in the infant — persistent dislocation after about 3 weeks, or the "Pavlik harness disease" of a posteriorly subluxed femoral head eroding the posterior acetabulum (abandon the harness)

• Failed closed reduction under anaesthesia — an irreducible hip, or one reducible only in an unsafe (extreme or forced) position outside the safe zone of Ramsey
• Unstable or non-concentric closed reduction — arthrogram shows an excessive medial dye pool (greater than the contralateral side), indicating interposed soft tissue
• Late-presenting DDH — the walking child, or any child presenting beyond the age at which closed methods reliably succeed (commonly cited beyond 18-24 months)
• Teratologic / syndromic dislocation — fixed antenatal dislocations (e.g. arthrogryposis, myelomeningocele) that are irreducible closed Age-based strategy — the classic exam framework. Management of DDH is stratified by age, and approach selection follows from it:

Approach selection. The medial approach suits the young child who needs no acetabular procedure; the anterior approach is favoured in the older child because it allows capsulorrhaphy and a concurrent pelvic osteotomy through the same exposure:

Relative contraindications and cautions. A hip that achieves a safe, concentric, stable CLOSED reduction should not be opened. A very high, long-standing bilateral dislocation in an older child may be left if it is painless and function is acceptable — an individualised decision, as some advocate leaving a painless bilateral dislocation. Active local infection or unfitness for anaesthesia also stay the surgeon's hand. Consent specifically for avascular necrosis (the principal long-term risk), redislocation or loss of reduction, residual dysplasia needing later surgery, lateral femoral cutaneous nerve injury (anterior approach), MFCA injury (medial approach), infection, and the prolonged spica cast with its hygiene implications. Setup. Supine. For the medial approach the hip is flexed, abducted and externally rotated for access (an access position, not the cast position). For the anterior approach a sandbag or bump under the ipsilateral buttock tilts the pelvis; the hemipelvis and whole leg are prepped free with the image intensifier available. Examination under anaesthesia with an arthrogram is performed first to confirm whether the hip reduces closed and concentrically.

The goal is to remove every obstacle, seat the femoral head concentrically in the true acetabulum, and hold it in the safe human position — while protecting the blood supply to the femoral head. The exposure IS the heart of the operation: the timeline below runs through the shared start (EUA and arthrogram, setup), then the MEDIAL approach for the young child and the ANTERIOR approach for the older child as two parallel branches, finishing with the shared spica and imaging steps.

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Rehabilitation | Phase | Timing | Immobilisation | Focus | |-------|--------|----------------|-------| | Immediate | 0-6 weeks | Spica in the human position; post-op CT or MRI confirms reduction | Meticulous cast and perineal hygiene; parental education; watch for pressure areas and soiling; simple analgesia | | Cast change | around 6 weeks | EUA to confirm stability; re-image; reapply spica or transition to an abduction orthosis | Confirm a maintained concentric reduction | | After cast removal | 6-12 weeks | Removable abduction brace (e.g. nights and naps) | Gentle mobilisation; hips are stiff after casting — gradual return of motion, physiotherapy if slow | | Return to function | from 3 months | None | Age-appropriate weight-bearing; full activity returns over weeks to months | Surveillance imaging is critical and long-term. Serial radiographs (3-6 monthly initially, then yearly) monitor AVN (ossific nucleus appearance and growth, fragmentation; Kalamchi-MacEwen grading), acetabular development (acetabular index trending down toward normal), and concentricity and head coverage. Follow to skeletal maturity — residual dysplasia may declare late and require pelvic osteotomy years after a "successful" reduction. Complications

Epidemiology. Developmental dysplasia of the hip covers a spectrum from a clinically unstable neonatal hip (Barlow or Ortolani positive) through to a fixed dislocation in the walking child. It is more common in girls, in the left hip, and in first-born children; breech presentation, oligohydramnios and a positive family history are recognised risk factors. The instances that reach open reduction are typically those that have failed harness or closed management, or that presented late. Pathoanatomy of the dysplastic hip. A chronically dislocated hip remodels in characteristic ways the surgeon must understand to achieve and hold a reduction: - The femoral head is displaced supero-laterally (and posteriorly), is smaller and often slightly flattened, with excessive femoral anteversion and coxa valga.

• The true acetabulum is shallow, anteverted and antero-laterally deficient; it is filled with pulvinar and obscured by the hypertrophied ligamentum teres and transverse acetabular ligament.
• The transverse acetabular ligament (TAL) is the inferior continuation of the labrum across the acetabular (cotyloid) notch; hypertrophied and tight, it tightens with the ligamentum teres and must be divided to deepen the true acetabulum — failure to divide it is a cause of failed or incomplete reduction.
• The labrum (limbus) is infolded (the "inverted limbus"), blocking the entrance.
• The capsule is stretched and redundant supero-laterally but constricted in the middle by the overlying iliopsoas tendon, producing the classic hourglass (figure-of-eight) deformity. Why the head will not reduce — the obstacles. Classically divided into extra-articular (a tight iliopsoas producing the hourglass capsular constriction; a contracted adductor mass) and intra-articular (inverted limbus or labrum, hypertrophied ligamentum teres, pulvinar, hypertrophied transverse acetabular ligament). A concentric reduction is impossible until each relevant obstacle is dealt with — hence the TIP-TOP mnemonic. Femoral shortening rather than traction. Historically, pre-operative skin or skeletal traction was used to bring the head down to the level of the acetabulum and was believed to reduce AVN; modern evidence does NOT support routine traction as protective. Primary femoral shortening osteotomy has largely replaced it in the older child: it decompresses the reduction, allows correction of anteversion and coxa valga, and is associated with LOWER AVN rates than forcing a tense reduction. Pelvic osteotomy as an adjunct. In the older child the acetabulum is shallow and antero-laterally deficient. A redirectional Salter innominate osteotomy (or a Pemberton or Dega acetabuloplasty, which hinges on the triradiate cartilage to reshape the roof) is added to provide anterolateral coverage once a concentric reduction is achieved. Special situations. In bilateral DDH the procedures may be staged or combined with careful anaesthetic and positioning planning; bilateral disease may present later because a symmetrical gait masks the diagnosis. The older child (greater than 3 years) or a very high dislocation should be planned for femoral shortening with derotation and a pelvic osteotomy routinely, with counselling that AVN and residual dysplasia risks rise with age at reduction. Teratologic dislocations (arthrogryposis, myelomeningocele) carry higher redislocation and stiffness rates and are individualised. Key evidence. The pooled data (Novais 2016) show no difference in osteonecrosis between the medial and anterior approaches (roughly 19% each) or by age — so approach choice can rest on surgeon preference and the need for capsulorrhaphy or a pelvic osteotomy rather than on AVN risk, and deliberately delaying reduction past one year to protect the head is not supported. The under-24-month comparison by Ergin (2021) confirms comparable mid- to long-term outcomes between approaches. Doski's RCT (2025) favours a proximal (brim) iliopsoas release for fewer MFCA injuries and less AVN. Desai (2024) identifies older age, a high dislocation, and a pelvic osteotomy without femoral shortening as independent stiffness risk factors. Balioglu (2015) demonstrates durable acetabular index correction with a Pemberton acetabuloplasty.

1. Salter RB (1961). Innominate osteotomy in the treatment of congenital dislocation and subluxation of the hip. J Bone Joint Surg Br. — Foundational description of the innominate (Salter) osteotomy and the principles of concentric reduction in DDH. 2. Ludloff K (1908/1913). The open reduction of the congenital hip dislocation by an anterior incision (medial approach). — The original description of the medial approach to open reduction. 3. Ferguson AB Jr (1973). Primary open reduction of congenital dislocation of the hip using a median adductor approach. J Bone Joint Surg Am 55(4):671-689. — The original description of the medial (adductor) approach and its outcomes. 4. Kalamchi A, MacEwen GD (1980). Avascular necrosis following treatment of congenital dislocation of the hip. J Bone Joint Surg Am 62(6):876-888. — The widely used radiographic classification of AVN and growth disturbance after DDH treatment. 5. Tachdjian MO. Pediatric Orthopaedics — the standard textbook reference for the obstacles to reduction and the surgical approaches to DDH. 6. Novais EN, Hill MK, Carry PM, Heyn PC (2016). Is age or surgical approach associated with osteonecrosis in patients with developmental dysplasia of the hip? A meta-analysis. Clin Orthop Relat Res 474(5):1166-1177. PMID 26472583. 7. Ergin ON, Demirel M, Meric E, Sensoy V, Bilgili F (2021). A comparative study of clinical and radiological outcomes of open reduction using the anterior and medial approaches for DDH. Indian J Orthop 55(1):130-141. PMID 33569107. 8. Doski J (2025). Proximal versus distal tenotomy of the iliopsoas tendon in the surgical treatment of DDH: a randomized clinical trial. Int Orthop 49(3):581-588. PMID 39853427. 9. Desai VM, Hall CE, Cardin S, et al. (2024). Prevalence and risk factors for stiffness following open reduction for DDH. J Pediatr Orthop 44(10):e908-e914. PMID 39021118. 10. Balioglu MB, Oner A, Aykut US, Kaygusuz MA (2015). Mid-term results of Pemberton pericapsular osteotomy. Indian J Orthop 49(4):418-424. PMID 26229162.