Hip Fracture Classification
Hip fractures are classified by their anatomical relationship to the hip joint capsule. This distinction drives prognosis (risk of avascular necrosis and nonunion), operative planning and immediate ED priorities.
Always record and communicate: intracapsular vs extracapsular, displacement (undisplaced vs displaced / Garden stage for neck fractures), comminution and any reverse‑oblique or subtrochanteric extension (NICE CG124; RCEM toolkit).
Anatomical basis and clinical relevance
- The hip capsule inserts around the base of the femoral neck. Fractures proximal to that insertion are intracapsular; those distal are extracapsular.
- Intracapsular (femoral‑neck) fractures risk disruption of the retinacular blood supply to the femoral head, with higher rates of avascular necrosis (AVN) and nonunion.
- Extracapsular fractures (trochanteric / subtrochanteric) lie outside the capsule; femoral‑head blood supply is usually preserved and mechanical stability / fracture geometry primarily determine fixation strategy.
- Basal cervical fractures occur at the capsular insertion and often behave biomechanically like extracapsular fractures; manage and prognosticate accordingly.
Classification by location
- Intracapsular (within capsule)
- Subcapital: just below the femoral head.
- Transcervical: through the mid‑portion of the femoral neck.
- Basal cervical: at the level of capsular insertion; often behaves like extracapsular injuries.
- Each intracapsular subtype may be undisplaced or displaced; displacement strongly influences prognosis and operative choice.