Hip Medial Approach (Ludloff)

Historical Context

The medial approach to the hip was first described by Karl Ludloff in 1908 for open reduction of congenital hip dislocation (DDH) in infants. It gained popularity in the early 20th century as one of several approaches for managing DDH before modern understanding of closed reduction and Pavlik harness treatment.

Modern Applications

The Ludloff medial approach has very limited applications in modern orthopedic surgery:

Primary Current Use:

• Open reduction of DDH in infants (6-18 months age range)
• Considered by some as less traumatic than anterior approach in very young children

Rare Adult Applications:

• Open psoas tendon release (now mostly done arthroscopically)
• Access to medial hip capsule (rarely needed)
• Historical interest and exam knowledge

NOT Used For:

• Primary total hip arthroplasty
• Revision hip surgery
• Acetabular fracture fixation
• Femoral neck fracture fixation

Key Statistics

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Adductor Compartment Anatomy

The medial approach works through the adductor compartment of the thigh:

Superficial Layer (Anterior to Posterior):

1. Pectineus - femoral nerve innervation (accessory obturator sometimes)
2. Adductor longus - obturator nerve (anterior division)
3. Gracilis - obturator nerve (anterior division)

Deep Layer:

1. Adductor brevis - obturator nerve (anterior division)
2. Adductor magnus (adductor portion) - obturator nerve (posterior division)
3. Obturator externus - obturator nerve (posterior division)

Critical Neurovascular Structures

Obturator Nerve:

• Originates from L2-L4 (lumbar plexus)
• Exits pelvis through obturator canal
• Divides into anterior and posterior divisions near obturator foramen
• Anterior division: Runs between adductor longus and brevis
• Posterior division: Runs between adductor brevis and magnus
• Provides motor to adductors and sensation to medial thigh

Medial Femoral Circumflex Artery (MFCA):

• Branch of profunda femoris (deep femoral) artery
• Runs posteriorly between pectineus and iliopsoas
• Courses behind femoral neck to supply femoral head
• PRIMARY blood supply to femoral head in adults
• Injury can cause AVN of femoral head

Other Structures:

• Profunda femoris artery (origin of MFCA)
• External pudendal vessels (superficial)
• Femoral vein (medially in femoral triangle)

The Adductor Interval (Surgical Plane)

The "interval" used in the medial approach is between:

• Adductor longus (anteriorly)
• Gracilis and adductor brevis (posteriorly)

This is NOT a true internervous plane because both muscles are supplied by the obturator nerve. The approach works by retracting muscles, not by exploiting nerve boundaries.

No True Internervous Plane

Unlike the posterior approach to the hip (which has a true internervous plane between inferior gluteal and superior gluteal nerve territories), the medial approach has NO true internervous plane.

Why Not an Internervous Plane?

The surgical dissection passes through the adductor compartment, where all muscles are innervated by the obturator nerve:

• Pectineus: Femoral nerve (L2-L3) - but accessory obturator in 10%
• Adductor longus: Obturator nerve (anterior division, L2-L4)
• Adductor brevis: Obturator nerve (anterior division, L2-L4)
• Gracilis: Obturator nerve (anterior division, L2-L4)
• Adductor magnus (adductor part): Obturator nerve (posterior division, L2-L4)

Clinical Implication:

• The approach works by retracting muscles, not by dissecting between nerve territories
• Care must be taken not to injure branches of the obturator nerve
• Excessive retraction can cause traction neuropraxia of the obturator nerve

Comparison with Other Hip Approaches:

Examination Pearl: When asked about the internervous plane of the medial approach, the correct answer is: "There is no true internervous plane. The approach passes through the adductor interval, but all surrounding muscles are supplied by the obturator nerve."

Supine Position with Hip Abduction

Standard Position: The patient is positioned supine on a radiolucent table with the affected hip exposed.

Key Positioning Elements:

1. Supine Position

   • Patient lies flat on back
   • Pelvis must be level (check ASIS equality)
   • Radiolucent table for imaging if needed

2. Hip Position

   • Affected hip flexed approximately 45 degrees
   • Externally rotated approximately 45 degrees
   • Abducted to expose medial thigh
   • This relaxes the adductor muscles and opens the interval

3. Knee Position

   • Knee flexed approximately 45-90 degrees
   • Reduces tension on adductor muscles
   • May rest on a bolster or assistant holds leg

4. Contralateral Leg

   • Positioned out of the way
   • May be placed in stirrup or on arm board

Alternative: Frog-Leg Position:

• Hip flexed, abducted, and externally rotated
• Knee flexed, foot resting on opposite thigh or table
• "Figure of 4" position
• More commonly used in pediatric DDH cases

Imaging Considerations:

• Fluoroscopy access if needed (rarely in adult cases)
• For DDH: arthrogram may be performed to assess reduction

Draping:

• Circumferential draping of the entire lower limb
• Medial thigh from groin crease to mid-thigh exposed
• Genitalia must be protected and isolated

Rationale for Medial Approach

The medial approach was developed to address specific pathology that required medial access to the hip joint:

Historical Indication - DDH Open Reduction:

In developmental dysplasia of the hip (DDH), the femoral head is dislocated posterosuperiorly from the acetabulum. The medial approach allows:

1. Release of Obstructions to Reduction:

   • Iliopsoas tendon (can be divided)
   • Pulvinar (fibrofatty tissue in acetabulum)
   • Ligamentum teres (hypertrophied)
   • Transverse acetabular ligament (may need release)

2. Direct Access to Capsule:

   • Medial capsule can be opened
   • Can access the joint without major muscle damage

3. Preservation of Blood Supply:

   • Theoretically avoids MFCA if careful (debated)
   • May cause less AVN than anterior approach (controversial)

Biomechanical Considerations:

The approach disrupts:

• Adductor muscle function (temporary weakness from retraction)
• Potentially the psoas tendon (if released)
• Does NOT affect abductors or hip extension

The approach preserves:

• Gluteus medius and minimus (abductors)
• Gluteus maximus (extension)
• Short external rotators (posterior stability)

Limitations for Adult Hip Surgery:

1. Cannot Visualize Acetabulum Well:

   • Medial approach gives very limited acetabular exposure
   • Cannot place acetabular component for THA

2. Cannot Expose Femoral Shaft:

   • No access to proximal femoral diaphysis
   • Cannot perform femoral osteotomy

3. High Risk to MFCA:

   • The medial femoral circumflex artery is in the surgical field
   • Damage can cause AVN of femoral head

Pre-operative Assessment for Medial Approach

History:

• Age of patient (medial approach most appropriate for infants)
• Duration of hip pathology
• Previous treatments (Pavlik harness, closed reduction attempts)
• Walking ability (for older children/adults)

Physical Examination:

1. Hip Range of Motion:

   • Assess flexion, extension, rotation
   • Document any contractures
   • Limited abduction may indicate DDH

2. Adductor Assessment:

   • Adductor tightness common in DDH
   • Grade adductor strength (baseline documentation)
   • Assess for obturator nerve function pre-operatively

3. Gait Pattern (if ambulatory):

   • Trendelenburg gait suggests abductor weakness
   • Limb length discrepancy with DDH

4. Leg Length:

   • True leg length measurement
   • Galeazzi test in infants (DDH)

Special Tests:

• Barlow test: Hip can be dislocated posteriorly (DDH)
• Ortolani test: Dislocated hip can be reduced with abduction (DDH)
• Ober test: IT band contracture
• Thomas test: Hip flexion contracture

Imaging for Medial Approach Cases

Plain Radiography:

• AP pelvis: Assess hip joint congruence
• Lateral hip: Evaluate femoral head position
• Shenton line disruption indicates subluxation/dislocation

Ultrasound (Pediatric DDH):

• Graf classification for infant hips
• Alpha and beta angles
• Dynamic assessment of stability
• Gold standard for under 4 months age

Arthrography:

• Intra-operative during DDH reduction
• Assess adequacy of reduction
• Identify soft tissue blocks to reduction

MRI:

• Assess cartilaginous structures (not visible on X-ray)
• Evaluate labrum, ligamentum teres
• Rarely needed for medial approach planning

CT Scan:

• Assess bony anatomy in complex cases
• Version measurements
• Rarely needed for medial approach

Operative Planning Checklist

Complications Specific to Medial Approach

Avascular Necrosis (AVN) of Femoral Head:

• Incidence: 5-15% in DDH open reduction series
• Mechanism: Injury to MFCA during surgery, or excessive pressure on femoral head
• Risk factors: Older age at surgery, more severe dislocation, previous closed reduction attempts
• Prevention: Meticulous surgical technique, avoid excessive manipulation
• Management: Containment strategies, may need arthroplasty if severe

Obturator Nerve Palsy:

• Incidence: Rare (under 2%) if careful technique
• Presentation: Weakness of hip adduction, sensory loss medial thigh
• Prevention: Identify nerve, avoid excessive retraction, protect branches
• Recovery: Neuropraxia usually recovers in weeks to months

Redislocation/Subluxation (DDH cases):

• Incidence: 5-10% in published series
• Cause: Inadequate reduction, instability, non-compliance with immobilization
• Prevention: Confirm reduction with arthrography, adequate immobilization
• Management: Repeat closed or open reduction, consider pelvic osteotomy

Post-operative Protocol (Pediatric DDH)

Immediate Post-operative Period:

• Hip spica cast application in operating room
• Position: Flexion 90-100°, abduction 40-50°, neutral rotation
• "Human position" for hip stability
• Confirm position with X-ray

Spica Cast Care:

• Cast typically for 6-12 weeks total (often split into two periods)
• Skin care around cast edges
• Monitor for cast complications (pressure sores, tight cast)
• May change cast at 6 weeks under anesthesia

Imaging Follow-up:

• Post-operative X-ray to confirm reduction
• X-ray at cast removal
• Regular follow-up X-rays until skeletal maturity

Mobilization After Cast Removal:

• May need abduction brace/splint
• Physiotherapy for range of motion
• Gradual return to weight-bearing
• Full activities over 3-6 months

Long-term Follow-up:

• Annual X-rays until skeletal maturity
• Monitor for:
  • Residual dysplasia (may need pelvic osteotomy)
  • AVN changes (Kalamchi-MacEwen classification)
  • Coxa vara/valga
  • Leg length discrepancy

Expected Outcomes

DDH Open Reduction via Medial Approach:

Favorable Prognostic Factors:

• Earlier age at reduction (under 12 months)
• Less severe initial dislocation
• Successful concentric reduction achieved
• No AVN complications

Poorer Prognosis:

• Delayed diagnosis/treatment (over 18 months)
• Higher Tonnis grade at presentation
• AVN development
• Residual instability requiring further surgery

Orthopaedic Examination Perspective

Relevance to Orthopaedic Exam: The medial approach to the hip is LOW YIELD for the adult reconstruction and general orthopedic components of the Orthopaedic exam. Key points to know:

1. Historical knowledge only - understand it exists and basic anatomy
2. NOT used for THA - know why (poor exposure, MFCA risk)
3. Pediatric indication - primarily for DDH open reduction
4. Obturator nerve and MFCA as key structures at risk

Australian Practice:

• Medial approach is rarely performed in adult practice
• DDH management in Australia follows established pediatric protocols
• Most surgeons use anterior, lateral, or posterior approaches for adult hip surgery

For Orthopaedic Candidates: Focus your hip approach preparation on:

1. Anterior approach (Smith-Petersen) - increasingly popular
2. Anterolateral (Watson-Jones) - common for hemiarthroplasty
3. Direct lateral (Hardinge) - most common in Australia
4. Posterior (Moore/Southern) - important alternative

Know the medial approach exists, its basic anatomy and indications, but do not spend excessive time on detailed technique.