Neck of femur fractures are one of the commonest fractures in the population as bone density in the thigh area drops in elderly women after the menopause, with large numbers of hospital beds dedicated to this group. Abnormal stresses repeatedly applied to the neck of femur such as by long distance runners or military trainees can result in stress fractures of the femoral neck in this much fitter and younger group. Direct trauma to the area such as a fall on the side of the hip can cause fracture at any age as can fractures secondary to pathological changes such as neoplasm.

The circulatory anatomy of the femoral head and neck have long convinced specialists in orthopaedics that it is vital to restore the bony alignment of the fragments to avoid the risk of avascular necrosis (AVN) in the head of the femur. A fracture can cause loss of the blood supply in the femoral head, allowing it to die and collapse which causes significant problems and requires operation. Keeping patients immobilised in a hip plaster spica was used initially until Smith-Petersen developed a more predictable internal fixation in the 1930s. The Richards Screw Plate uses compression applied to the fracture site by a sliding fixation technique.

Walking puts both shearing and compression forces across the neck of femur in normal life but these forces are greatly magnified by activities such as sports involving jumping, sprinting or running. A typical increase in force of five to six times the bodyweight occurs across the femoral neck in normal activities such as climbing stairs. Hip pain refers commonly to the front of the thigh, side of the hip and the groin in a number of hip syndromes including a stress fracture, which can develop into a complete fracture plus displacement with the attendant risks.

If abnormally increased levels of stress are imposed on normal bone by a healthy individual the bony trabeculae which resist mechanical forces can fail and the result is a stress fracture. In older women after the menopause the bone is abnormal due to pathological insufficiency from metabolic conditions or osteoporosis and in this case normal mechanical stresses can be too much for the bony structures. Bone health and turnover are maintained by oestrogen levels and once the hormonal levels drop bone develops brittleness, both in female sportspeople who train very highly or in older females.

A specialist will consider stress fracture in the differential diagnosis of an athlete who, after an increase in training, presents with a new hip pain problem. The pain is generally worse with the sport and better with resting. Bone scanning is a more sensitive investigation than x-rays in this case. The vast majority of these fractures occur in elderly persons who fall or twist, fracturing the femoral neck. Diagnosis is established by noting an inability to stand on the leg, a laterally rotated leg, a shortened limb and pain in the side of the hip and the groin.

There is a ten to fifteen percent chance of transverse femoral neck fractures displacing with the consequent problems of avascular necrosis. Typically these fractures require surgical management and the orthopaedic specialist must choose the correct approach. The anatomical position of the fracture dictates the subsequent management, being either the replacement of the whole joint or internal fixation of the fracture. Sub-capital fractures, just below the femoral head, are likely to interfere with the circulation and in these cases joint replacement or Thompson hemiarthroplasty are preferred.

If the fracture is not displaced and is under compression due to the nature of the injury then conservative management is indicated and surgery unnecessary. If the fracture is under tension it is unstable and has the potential to displace and requires internal fixation with one of the many fracture fixation devices. This applies to lower femoral neck fractures, trochanteric and sub-trochanteric fractures. Fractures are fixed as soon as possible after the injury, allowing for the medical condition of the patient.

The patient is rested for 24 hours after the operation to fix or replace their fracture to allow them to recover. Once the operative instructions have been noted and the patient’s medical condition checked, a physiotherapist and an assistant will mobilise the patient with a frame or crutches.