Pelvic Dislocation & Associated Nerve Injuries
Brief overview
Traumatic hip dislocation is an orthopaedic emergency that usually follows high‑energy mechanisms (motor vehicle collisions, falls from height) but can occur with low‑energy events in prosthetic hips. Management follows major‑trauma priorities (ABCDE) and requires prompt reduction once life‑threatening injuries are addressed, careful neurovascular documentation, and early orthopaedic involvement (NICE NG39; MoD synopsis).
Key practical points
- Posterior dislocations are most common (≈90%); anterior dislocations are uncommon (≈10%).
- Sciatic nerve injury is a recognised complication of posterior dislocation (reported ~8-19% in trauma series).
- Femoral‑nerve injury is described with anterior dislocations in orthopaedic texts.
- Aim for the earliest safe reduction; delays (especially >12 hours) markedly increase the risk of avascular necrosis (AVN).
- After reduction obtain CT of the hip/acetabulum to detect intra‑articular fragments and occult fractures.
- Use whole‑body CT in major trauma per local major‑trauma guidance (NICE NG39).
Anatomy and mechanism
- Hip: ball‑and‑socket joint (femoral head - acetabulum); stability from bony congruity, labrum, capsule and surrounding muscles.
- Nerves at risk:
- Sciatic nerve (L4-S3): runs posterior to the hip and splits into tibial and common peroneal branches - vulnerable in posterior dislocations.
- Femoral nerve (L2-L4): lies anterior to the hip - described with anterior dislocations.