Revision Total Hip Arthroplasty - Femoral Component

Danger Structures

• Superior gluteal nerve - exits greater sciatic notch 25-40mm proximal to tip of greater trochanter, supplies gluteus medius and minimus, injury causes irreversible abductor weakness and Trendelenburg gait - EXAM KEY: stay within 5cm distal to greater trochanter tip (safe zone), never extend split proximally beyond this
• Inferior gluteal nerve - enters gluteus maximus 20-30mm inferior to piriformis, injury rare in lateral approach - EXAM KEY: protected by staying anterior to muscle belly
• Femoral nerve - lies 40-60mm anterior/medial to surgical field, at risk with over-aggressive anterior retractor placement - EXAM KEY: anterior retractor should stay on bone (ilium/acetabular rim), never slide medially
• Sciatic nerve - runs 30-40mm posterior to hip joint, less at risk than posterior approach but can be injured with posterior retractor - EXAM KEY: posterior retractor should stay on ischium/posterior wall, limit retraction time
• Lateral femoral cutaneous nerve - runs 50-70mm anterior/superior to incision, generally safe in direct lateral approach - EXAM KEY: incision centered on GT, not extending too far anterior/superior
• Profunda femoris artery with medial/lateral femoral circumflex branches - at risk during vastus lateralis mobilization 40-50mm distal to lesser trochanter - EXAM KEY: subperiosteal dissection along vastus ridge protects vessels