Proximal femoral fractures are a subset of fractures that occur in the hip region. They tend to occur in older patients, and in those who have osteoporosis. In this group of patients, the fracture is usually the result of low-impact trauma although, in younger patients they are usually victims of high-impact trauma, usually during a car accident.

Anatomy

The anatomy of the region is important when considering fractures of the proximal femur. Blood supply for the femoral head is derived from vessels within the hip capsule. There are two sources of blood supply: the trochanteric and cruciate anastomoses ¹. 

The trochanteric anastomosis ¹ consists of the following vessels:

• superior gluteal artery
• medial circumflex artery (main supply of blood to the femoral head)
• lateral circumflex artery

The cruciate anastomosis ¹ consists of:

• inferior gluteal artery
• medial circumflex artery
• lateral circumflex artery
• first perforating branch of the profunda femoris

When a fracture of the femoral neck occurs, disruption to these blood vessels can occur result in devascularisation of the femoral head and resulting avascular necrosis.

Classification

Proximal femoral fractures are therefore divided into groups based on their location with regard to the capsule, i.e. whether they are intracapsular or extracapsular.

Intracapsular fractures

Intracapsular fractures are important because of their propensity to damage the small intracapsular vessels that provide the majority of the blood supply to the femoral head. Femoral neck fractures must therefore be diagnosed and treated appropriately in order to reduce the morbidity from the consequences of devascularisation.

Femoral head fractures are rare intracapsular injuries but are very different from femoral neck fractures in that they do not cause disruption to the vessels that supply blood to the femoral head. They usually occur secondary to femoral head dislocation.

Extracapsular fractures

Fractures outside the capsule do not cause the same degree of vascular damage as intracapsular fractures and therefore can be treated differently. The trochanteric fractures are extracapsular injuries.