Hip for FRCS (Tr & Orth)

What the paper tends to test

• Approach questions ask for the nerve at risk: the sciatic nerve in the posterior approach, the superior gluteal nerve when the gluteus medius split of a lateral approach is extended proximally, the lateral femoral cutaneous nerve in the direct anterior approach.
• Bearing questions test the trade-offs of metal or ceramic on highly cross-linked polyethylene, ceramic on ceramic and metal on metal, and the wear and failure mode typical of each.
• Periprosthetic femoral fracture is tested through the Vancouver classification and what it means for treatment: fix a fracture around a well-fixed stem, revise a loose one.
• Infection questions ask you to choose between debridement with implant retention, one-stage and two-stage revision from the timing of symptoms and the stability of the implant.
• Young adult hip questions describe cam or pincer morphology, or a shallow acetabulum, and ask for the diagnosis or the appropriate joint-preserving operation.

Classic traps and discriminators

• The decision in a Vancouver B fracture is whether the stem is loose. A loose stem treated by fixation alone fails; a B2 fracture mistaken for a B1 is the classic error.
• A Trendelenburg gait after a lateral approach points to abductor failure or injury to the superior gluteal nerve, not to leg-length discrepancy.
• Highly cross-linked polyethylene wears less, but cross-linking and remelting reduce its fatigue strength and fracture toughness — which matters for thin liners and locking-mechanism rims.
• The medial femoral circumflex artery supplies most of the femoral head through retinacular vessels that run along the posterosuperior neck, which is why a displaced intracapsular fracture threatens the head and why the artery is protected in surgical dislocation of the hip.
• MRI is the most sensitive test for early avascular necrosis; the crescent sign on a radiograph means subchondral collapse has already begun.

Free revision notes

Hip questions, answered