Fracture. of the upper femur

Epidemiology

Fractures of the upper end of the femur are both common and serious. In children a slipped upper femoral epiphysis (a fracture of the epiphyseal plate) will lead to a lifetime of pain and disability. In adults a fracture of the upper end of the femur is a very high-velocity injury which is difficult to treat. In the elderly fractured neck of femur is the ‘bread-and-butter’ of orthopaedic trauma practice, with over 100 000 cases of fractured neck of femur each year in Britain alone.

Subcapital fractured neck of femur

This is a very common fracture in the elderly osteoporotic patient. The sclerosis produced by osteoarthritis tends to protect the patient from this fracture so the hip joint itself is usually healthy at the time of the accident. The problem with this fracture is that the majority of the blood supply to the femoral head travels up the femoral neck. A subcapital fractured neck of femur (Fig. 23.14) may destroy the blood supply to the femoral head. The older the patient, and the more displaced the fracture, the less likely the head is to recover its blood supply.

History

Some patients actually give a history of feeling the femur break and then falling as a result of this, while others appear to break the femur as a result of the fall. Either way, they complain of severe pain in the hip and are usually unable to walk.

Examination

The leg may appear shortened and externally rotated.

Investigation

On an AP X-ray the fracture may be difficult to see, but it will be shown more clearly on the lateral view as the head may displace posteriorly. On the AP X-ray the only clue to the presence of a fracture may be a discontinuity in the trabecular lines running up the femoral neck into the head.

Treatment

The Garden classification divides these fractures into four grades (see Fig. 23.15 and Table 23.5):

grade 1 is an incomplete fracture of the neck;

grade 2 is a complete fracture of the neck without displacement;

grade 3 has moderate displacement of less than half the diameter of the femoral neck;

grade 4 is a complete off-ended femoral head as seen in the AP or lateral X-ray.

  If grade 1 or 2 fractures are left untreated they may rapidly displace and become grade 3 or 4.

In grade 1 fractures it is generally agreed, whatever the age group, that the treatment of choice is AO screws or other pins introduced up the femoral neck to hold the femoral head in position. In grade 4 fractures, whatever the age group, it is unlikely that the femoral head will survive. In patients under 50 years of age they should be taken to theatre as quickly as possible to reduce and pin the head as quickly as possible, and fix with screws (Fig. 23.16). The hope is that the femoral head will revascularise before it collapses. In patients older than this, the chance of survival of the femoral head is so low that it is best to replace it straight away. In young patients (under 65), a total hip replacement should be performed, but in older patients a hemiarthroplasty can be used. In the hemiarthroplasty the acetabulum with its normal articular cartilage is left alone but the patient’s femoral head is replaced by an implant whose head has the same diameter as the head being removed. This articulates with the patient’s normal acetabulum. The cemented variety of this implant is usually known as a ‘Thompson’ prosthesis; the uncemented variety is known as an Austin Moore’ (Fig. 23.17). There is good evidence that the cemented hemiarthroplasty does better than the uncemented in the long term. In the older patient (with a life expectancy of 5 years or less) it is normal to go ahead and perform a hemiarthroplasty on patients with a Garden 2, 3 or 4 fracture. The risk of avascular necrosis is so high and the destruction of quality of life when this occurs so great, that it is simpler to sort out the problem in one go. The chance of the hemiarthroplasty giving the patient good function to the end of their days is high and so this is the operation of choice.

Problems

If the femoral head is retained reduction can be difficult to achieve and if pins are used they may displace into the aceta­bulum. Avascular necrosis is then a risk depending on the age of the patient, the degree of displacement and the time to reduction. If the head is replaced then dislocation, bleeding and infection are early complications, as well as damage to the nerves around the hip when replacing the joint. Late complications are loosening of the replacement, and sometimes the acetabulum can be eroded away by the implant, creating a protrusio-type arthritis (Fig 23.18 and Fig 23.19).

  Subcapital fractured neck of femur

  Common in osteoporosis

  Treatment depends on displacement and age

  Complication — avascular necrosis