13.1 Developmental Dysplasia of the Hip (DDH), Clubfoot (Talipes Equinovarus) & Pediatric Hip Disorders

Developmental Dysplasia of the Hip (DDH), Clubfoot & Pediatric Hip Disorders

Core Clinical Principle: Pediatric orthopaedic conditions span dynamic developmental abnormalities, congenital structural deformities, and vascular or physeal hip pathologies. Early physical diagnosis, timely non-operative or operative intervention, and vigilant complications surveillance—such as guarding against avascular necrosis (AVN) in hip reductions and preventing deformity recurrence in clubfoot—are foundational to preserving lifetime joint congruity and function.

1. Developmental Dysplasia of the Hip (DDH): Spectrum & Risk Factors

Developmental Dysplasia of the Hip (DDH) represents a continuum of anatomical abnormalities in the immature hip joint, ranging from subtle acetabular dysplasia (shallow, vertical acetabular roof with a seated femoral head) to subluxation (partial contact loss), dislocatable hip (articular contact maintained at rest but displaced by provocative force), and complete dislocation (femoral head fully displaced outside the acetabular socket).

                      MAJOR CLINICAL RISK FACTORS FOR DDH
  ┌─────────────────────────────────────────────────────────────────────────────┐
  │ 1. Breech Presentation at Birth (Frank breech imparts highest risk: ~12%)   │
  │ 2. Female Sex (Female-to-male ratio ~8:1 due to maternal relaxin sensitivity)│
  │ 3. Positive Family History (First-degree relative with DDH; genetic laxity) │
  │ 4. Firstborn Child & Oligohydramnios (Intrauterine mechanical crowding)     │
  │ 5. Postnatal Swaddling Practices (Lower limbs tightly adducted & extended)  │
  └─────────────────────────────────────────────────────────────────────────────┘

Physical Examination Maneuvers in Infants

Physical examination of the neonatal and infant hip requires a calm, supine patient on a firm surface:

• Ortolani Maneuver (The Reduction Test):
  • Technique: The examiner places their thumbs on the infant's inner medial thighs and index/middle fingers over the greater trochanters laterally. The hips are flexed to 90° and then gently and smoothly abducted while applying an anterior lifting force through the greater trochanter.
  • Positive Finding: A palpable, audible "clunk" of reduction as the dislocated femoral head slips over the posterior-superior acetabular rim back into the true acetabular cup.
• Barlow Maneuver (The Provocation / Dislocation Test):
  • Technique: Starting with the infant's hips flexed to 90°, the examiner gently adducts the hip across the midline while applying a gentle, direct posterior pressure along the axis of the femoral shaft.
  • Positive Finding: A palpable sensation of the femoral head subluxating or dislocating posteriorly out of the acetabulum (a "clunk" or glide of exit).
• Galeazzi (Allis) Sign:
  • Technique: With the infant supine, hips flexed to 90°, knees flexed, and both feet flat side-by-side on the examination table, the examiner compares the vertical height of the patellae/knees.
  • Positive Finding: An apparent shortening of the limb on the affected side (the knee on the dislocated side sits noticeably lower due to posterior and superior displacement of the femoral head).
• Additional Clinical Signs in Older Infants (>3 Months):
  • Asymmetric, extra thigh and gluteal skin folds (unequal inguinal, gluteal, or popliteal creases).
  • Asymmetric Hip Abduction: Limitation of passive hip abduction to less than 60° when flexed at 90° (the most sensitive physical finding in infants >3–6 months as ligamentous laxity diminishes and capsular/adductor contractures develop).
  • In ambulating children: Trendelenburg gait (unilateral dislocation) or waddling "duck-like" gait with pronounced lumbar lordosis (bilateral dislocation).

2. Diagnostic Imaging Protocols for DDH

                      IMAGING PROTOCOLS BY PATIENT AGE
  ┌──────────────────────────────────────┬──────────────────────────────────────┐
  │ Age < 6 Months (Dynamic Ultrasound)  │ Age ≥ 6 Months (AP Pelvis X-Ray)     │
  ├──────────────────────────────────────┼──────────────────────────────────────┤
  │ • Femoral head is purely cartilaginous│ • Proximal femoral ossification center│
  │   and radiolucent on plain X-rays.   │   appears (at 4–7 months of age).    │
  │ • Dynamic Real-Time Ultrasound (Graf)│ • Standard AP Pelvis Radiograph      │
  │ • Measures Alpha Angle (acetabular   │   utilizing Hilgenreiner, Perkins, & │
  │   roof inclination; normal > 60°).   │   Shenton anatomical reference lines.│
  └──────────────────────────────────────┴──────────────────────────────────────┘

Radiographic Reference Lines (Children ≥6 Months)

1. Hilgenreiner Line (H-Line): A horizontal baseline drawn through the triradiate cartilages of both acetabula.
2. Perkins Line (P-Line): A vertical line drawn strictly perpendicular to the Hilgenreiner line at the lateral bony margin of the acetabular roof.
3. Quadrant Grid Evaluation: In a normal hip, the ossification center of the femoral head must lie in the inferomedial quadrant formed by the intersection of Hilgenreiner and Perkins lines. In a dislocated hip, the ossification center is displaced into the superolateral quadrant.
4. Shenton Line: A smooth, continuous parabolic arch drawn from the medial border of the femoral neck to the superior border of the obturator foramen. In DDH, this line is broken and discontinuous.
5. Acetabular Index: The angle formed between the Hilgenreiner line and an oblique line tangent to the sclerotic acetabular roof. Normal is <30° at birth and decreases to <20° by age 2. An angle >30° signifies acetabular dysplasia.

3. Pavlik Harness Management & Complications Surveillance

The Pavlik harness is a dynamic flexion-abduction orthosis and the first-line treatment for reducible DDH in infants from birth up to 6 months of age.

                      PAVLIK HARNESS BIOMECHANICAL PROFILE
  ┌─────────────────────────────────────────────────────────────────────────────┐
  │ • Anterior Straps: Maintain hip flexion at 90° to 100°                      │
  │ • Posterior Straps: Maintain moderate controlled hip abduction at 45° to 60°│
  │ • Wearing Schedule: Full-time (23 to 24 hours per day) for 6 to 12 weeks    │
  │ • Strap Adjustments: PERFORMED STRICTLY BY CLINICIAN to accommodate growth  │
  └─────────────────────────────────────────────────────────────────────────────┘

Critical Complications of Improper Harness Fit

• Femoral Nerve Palsy (Hyperflexion Injury): If anterior straps are overtightened, creating excessive hip flexion (>100°–110°), the femoral nerve is compressed under the inguinal ligament. The nurse must assess for active bilateral knee extension and quadriceps firing; loss of the spontaneous "kick" reflex indicates nerve impingement requiring immediate strap loosening.
• Avascular Necrosis (AVN) of Femoral Head (Hyperabduction Injury): If posterior straps force excessive abduction (>60°–70°), the medial femoral circumflex artery is compressed against the pubic ramus and acetabular rim, causing ischemic necrosis of the developing cartilaginous femoral head.
• Skin Care & Parent Guidance: The infant must wear a soft, snug cotton undershirt and long knee socks under all straps to prevent chafing. Parents are taught to inspect skin folds (groin, behind knees, axillae) daily for erythema, keep the harness dry during sponge baths, and never adjust the strap tension markers independently.

Closed Reduction & Hip Spica Cast Nursing Care (6–18 Months)

When harness treatment fails or DDH is diagnosed after 6 months, patients undergo closed reduction under general anesthesia (with arthrography) and application of a Hip Spica Cast positioned in the "human position" (90°–100° flexion, 45°–50° abduction):

1. Perineal Hygiene & Diapering: Insert a smaller disposable diaper inside the cast perineal cutout (tucking the edges smoothly) and apply a larger diaper over the outside of the cast to hold it in place. Apply waterproof tape ("petaling") with smooth, overlapping shingle-style edges around the groin cutout to protect plaster from urine and stool contamination.
2. Positioning & Pressure Injury Prevention: Turn the child every 2 hours while awake and asleep. Use small pillows or rolled towels to support the cast contours and elevate the heels off the mattress. Avoid lifting the child by the cast crossbar/spreader bar (which causes cast breakage or skin shearing).
3. Neurovascular Surveillance: Perform serial assessments of capillary refill, skin temperature, movement, and sensation of all exposed toes.

4. Congenital Talipes Equinovarus (Clubfoot): The CAVE Deformity

Congenital Talipes Equinovarus (CTEV) is a congenital complex 3-dimensional deformity of the foot and ankle characterized by the CAVE anatomical components:

                       THE 'CAVE' CLUBFOOT DEFORMITY
  ┌─────────────────────┬──────────────────────────────────────────────────────┐
  │ Component           │ Anatomical Deformity & Structural Pathology          │
  ├─────────────────────┼──────────────────────────────────────────────────────┤
  │ **C - Cavus**       │ Abnormally high medial longitudinal arch caused by   │
  │                     │ plantarflexion of the 1st metatarsal relative to hind│
  ├─────────────────────┼──────────────────────────────────────────────────────┤
  │ **A - Adductus**    │ Forefoot and midfoot rotated medially towards midline│
  │                     │ at the talonavicular and calcaneocuboid joints       │
  ├─────────────────────┼──────────────────────────────────────────────────────┤
  │ **V - Varus**       │ Hindfoot/calcaneus inverted and tilted medially      │
  ├─────────────────────┼──────────────────────────────────────────────────────┤
  │ **E - Equinus**     │ Ankle in fixed plantarflexion due to severe contract-│
  │                     │ ure of the Achilles tendon (triceps surae complex)   │
  └─────────────────────┴──────────────────────────────────────────────────────┘

The Ponseti Method: The Gold Standard Protocol

The Ponseti technique achieves permanent anatomical correction without major open surgical release through serial manipulative casting:

1. Serial Manipulative Casting (Weekly): Initiated within the first 1–2 weeks of life. Correction follows a strict chronological order: Correct Cavus FIRST, then Adductus and Varus, and Equinus LAST:
   • Cavus Correction: The forefoot is supinated and the first ray (1st metatarsal) is elevated to align the forefoot with the inverted hindfoot.
   • Adductus & Varus Correction: The forefoot is gradually abducted in supination while the clinician places their thumb on the lateral head of the talus as a fixed fulcrum. CRITICAL RULE: Never touch or grasp the calcaneus during abduction (grasping the heel blocks the calcaneus from naturally abducting and everting beneath the talus).
   • Long-Leg Cast: Applied with the knee flexed at 90° to prevent the cast from slipping down and maintain rotational control.
2. Percutaneous Achilles Tenotomy: Required in 85% to 90% of patients. Because the rigid, fibrotic Achilles tendon cannot be stretched safely without creating a "rocker-bottom" midfoot break, a complete percutaneous transection of the Achilles tendon is performed under local anesthesia. A final long-leg cast is applied for 3 weeks to allow tendon regeneration in lengthened alignment.
3. Foot Abduction Brace (FAB / Mitchell-Ponseti / Denis Browne):
   • Initial Phase: Worn 23 hours per day for the first 3 months.
   • Maintenance Phase: Worn 12 to 14 hours per day (during night sleep and naps) until age 4 to 5 years.
   • Brace Settings: Feet set at shoulder-width apart; affected foot externally rotated to 60°–70° (40° on normal side in unilateral cases) with 10°–15° dorsiflexion. Non-compliance with the FAB is the number one cause of clubfoot recurrence.

5. Slipped Capital Femoral Epiphysis (SCFE) vs. Legg-Calvé-Perthes Disease (LCPD)

Both conditions present with hip pathology in pediatric and adolescent populations but require vastly different clinical urgency and management.

               COMPARATIVE MATRIX: SCFE VS. LEGG-CALVÉ-PERTHES
  ┌─────────────────────┬──────────────────────────┬──────────────────────────┐
  │ Clinical Feature    │ SCFE                     │ Legg-Calvé-Perthes (LCPD)│
  ├─────────────────────┼──────────────────────────┼──────────────────────────┤
  │ **Peak Age & Sex**  │ Adolescents (11–15 yo)   │ Young children (4–8 yo)  │
  │                     │ Males > Females (2:1)    │ Males > Females (4:1)    │
  ├─────────────────────┼──────────────────────────┼──────────────────────────┤
  │ **Body Habitus**    │ Overweight / Obese       │ Small stature, slight    │
  │                     │ (Rapid pubertal spurt)   │ build, delayed bone age  │
  ├─────────────────────┼──────────────────────────┼──────────────────────────┤
  │ **Pathophysiology** │ Physeal shear failure    │ Idiopathic avascular     │
  │                     │ through hypertrophic zone│ necrosis (AVN) of femoral│
  │                     │ with posteroinferior slip│ head capital epiphysis   │
  ├─────────────────────┼──────────────────────────┼──────────────────────────┤
  │ **Presentation**    │ Dull groin/thigh/knee pain│ Insidious, painless or   │
  │                     │ Antalgic / Trendelenburg │ mild antalgic limp, worse│
  │                     │ limp; Drehmann sign (+)  │ after physical activity  │
  ├─────────────────────┼──────────────────────────┼──────────────────────────┤
  │ **Physical Exam**   │ **Obligate external**    │ Decreased internal       │
  │                     │ **rotation with flexion**│ rotation & abduction     │
  ├─────────────────────┼──────────────────────────┼──────────────────────────┤
  │ **Urgency & Tx**    │ **ORTHOPAEDIC EMERGENCY**│ Containment principle;   │
  │                     │ Strict NWB; Urgent In    │ PT, Petrie abduction     │
  │                     │ Situ Single Screw Fixation│ cast, containment osteotomy│
  └─────────────────────┴──────────────────────────┴──────────────────────────┘

Slipped Capital Femoral Epiphysis (SCFE)

• The Danger of Referred Knee Pain: Pain from SCFE is characteristically referred along the sensory distribution of the obturator and femoral nerves to the ipsilateral anteromedial thigh or knee. Any adolescent presenting with unexplained knee or distal thigh pain must undergo a mandatory hip physical examination and bilateral AP and frog-leg lateral pelvis radiographs.
• The Drehmann Sign: As the examiner passively flexes the patient's hip to 90°, the hip involuntarily and obligatorily rolls into marked external rotation and abduction because the displaced posterior-inferior femoral neck impinges on the anterior acetabular rim.
• Classification & Emergency Management:
  • Stable: Patient can bear weight (with or without crutches).
  • Unstable: Patient cannot bear weight even with crutches (AVN rate reaches up to 50%).
  • Action: IMMEDIATE STRICT NON-WEIGHT BEARING. The patient must be placed on bed rest and transported strictly via stretcher/wheelchair. Urgent surgical stabilization with a single percutaneous cannulated screw placed across the center of the physis is performed to arrest slip progression while avoiding AVN and chondrolysis.

Legg-Calvé-Perthes Disease (LCPD)

LCPD involves self-limiting ischemic necrosis of the capital femoral epiphysis followed by vascular re-invasion, resorption, and bone remodeling across four distinct Waldenström Stages:

1. Initial / Avascular Stage (0–12 mo): Ischemia causes chondrocyte death, subchondral fracture (crescent sign), and dense radiopacity of the small femoral head.
2. Fragmentation Stage (1–2 yr): Osteoclasts resorb necrotic bone; femoral head fragments, collapses, and widens (highest vulnerability to lateral extrusion).
3. Reossification / Reparative Stage (2–4 yr): Vascular granulation tissue and immature woven bone replace resorbed trabeculae; new bone advances across the femoral head.
4. Healed / Remodeling Stage: Femoral head reaches final shape; sphericity determines long-term joint congruency and premature osteoarthritis risk (Herring Lateral Pillar Classification).

• The Containment Principle: Management focuses on maintaining the malleable femoral head deeply "contained" within the spherical acetabular socket so the acetabulum acts as a biological mold during reossification. Conservative therapy includes range-of-motion physical therapy and abduction orthoses (Petrie cast, Scottish Rite brace); surgical containment (femoral varus osteotomy or pelvic Salter osteotomy) is indicated for older children (>6–8 years) or significant lateral pillar collapse.