Introduction

While there are four clinically acceptable surgical treatments for a displaced femoral neck fracture in the elderly, there is still controversy about which one to provide in a given situation. The four options are: closed reduction with internal fixation, unipolar hemiarthroplasty, bipolar hemiarthroplasty, and total hip arthroplasty.

The current figure for such fractures is 125,000 occurrences annually in the USA, and this amount is predicted to double by 2050, due to the rise in the numbers of its aging population. Femoral neck fractures account for about 30% of hip fractures globally, and for about 50% in the USA, with only 50% of patients surviving for 5 years after the fracture.

The review

Physicians from the Departments of Orthopedic Surgery at the Lahey Clinic in Massachusetts and at the University of Minnesota reviewed collections of studies reported in the literature to evaluate the outcomes of these four surgical treatments during a 2-year post-operative period - their complication rates, mortality, re-operation rates, and resulting physical function. Additionally, they determined the costs of hospitalization, operating room supplies and implants, the average hospital length of stay, the percentage of patients discharged to a rehabilitation hospital, and the average rehabilitation hospital length of stay, to see which method of treatment was the most cost-effective.

In short, they wanted to find out what method of surgical treatment gave the patient the most for his money.

Outcomes

The goal of treatment of this fracture is restoration of pre-fracture physical function without associated morbidity. Satisfactory recovery of ambulatory status correlates with younger age, comorbid medical conditions, competent mental status, male gender, community support structure, and the pre-fracture ambulatory status.

When patients with femoral neck fracture are grouped without regard to treatment option, 50-60% regain pre-fracture ambulatory status; 10-20% change status from ambulatory to non-ambulatory during the first year after injury.

Internal Fixation

This is commonly done using cannulated screws. Bony union is achieved in 67% of patients within 2 years. Thirty-five percent of patients require secondary procedures: conversion to a total hip arthroplasty, removal of the internal fixation device(s), and/or repeat internal fixation.

Seventy percent achieve a pain-free union during the first 2 years after surgery. The same number regain ambulatory status after 1 year. When all goes perfectly, this method of surgical repair gives the closest approximation to pre-fracture independence. When excellent bone healing occurs, it is the standard against which other treatment options are measured. But achieving this result may be difficult - as indicated above, problems arise in 35% of patients. Comorbidities such as increased age, dementia, malignancy, and cardiopulmonary disease are common in this group, and take their toll.

Urgent reduction and fixation (within 12 hours of the fracture) has been shown to reduce the risk of avascular necrosis in displaced neck fractures, but mortality and morbidity rates are higher when the medical condition of these patients is not optimized before surgery.

Unipolar Hemiarthroplasty

With this method, there is an 80% implant survival 7 years after surgery. Seventy percent of patients regain ambulatory status at 1 year, and 80% report 'no pain' or only mild pain at 1 year. However, active patients are not completely satisfied with this method of treatment, developing stiffness (decreased range of motion) or erosion of the acetabulum with groin pain over time.

Bipolar Hemiarthroplasty

At 2 years post-op there is a reported 85% incidence of 'no pain' 2 years post-op, and 85% are able to walk without aids or with only one cane. This method is attractive in patients with neurological impairment and risks of hip instability (stroke, Parkinsonism, or dementia).

Total Hip Arthroplasty

This is one of the most enduring and successful orthopedic interventions developed for patients with arthritis. Traditionally, it has been used in femoral neck fracture patients when they have pre-existing painful hip arthritis, Paget's disease, renal osteodystrophy, or osteopenia. Ninety percent of patients report no or slight pain 2 years post-op, and walking without aids or the use of only one cane occurs in 87% of patients at 2 years post-op. There is survival of the prosthesis in 96% of cases at 4 years.

Complications

The incidence of deep vein thrombosis and pulmonary embolism is not significantly different among patients treated with internal fixation, hemiarthroplasty, or total hip arthroplasty. Infection rates have been higher among patients undergoing arthroplasty using the posterior approach compared with other approaches. When prophylactic antibiotics and a clean modern operating room are used, the infection rates among the four operations should not differ.

Mortality rates show no significant statistical differences between the four different treatment methods.

Cost-effectiveness

The authors refer to a study done in Sweden¹ which showed the total cost of treating such fractures depends on three factors: the primary operative technique, the method used for rehabilitation, and the skill with which fracture complications were handled. Healing complications occurred in 30% of patients. Fractures treated without complications consumed 31 cost-standardized bed days, whereas those with complications consumed 101 bed days.

The authors studied the economics of displaced femoral neck fractures in their clinics in 185 patients, aged 65 or over, between October 1993 and September 1996. They included initial hospital costs, rehabilitation costs, and costs of re-operations and complications, but not professional (physician) costs.

The 4 treatment-method groups were similar (not significantly different) for all pre-operative parameters: the pre-operative living situation, the number of comorbid medical conditions, and mean age at the time of surgery.

Calculated costs per patient for the 4 procedures did not vary much - they were $10,385 for internal fixation, $9,190 for unipolar or bipolar hemiarthroplasty, $10,490 for cemented and $11,886 for hybrid total hip arthroplasty.

Using inpatient hospital costs, rehabilitation costs, and the probability of surgical revision within two years, total hip arthroplasty was the most cost-effective procedure. It also provided a less painful, more mobile, and more functional outcome, when compared with hemiarthroplasty. The procedure should, of course, be performed by an experienced arthroplasty surgeon.

Recommendations

Based on their analyses, the authors of this study constructed an algorithm for selecting the best treatment for patients 65 or older with a fractured neck of femur: Patients should be classified as previously ambulatory, or non- or poorly-ambulatory.

Those ambulatory patients with good bone stock, good joint space, and suitable for immediate surgery should have internal fixation. Ambulatory patients with poor bone stock, poor joint space, arthritic hip pain, and delay before surgery should have a total hip arthroplasty.

Non- or poor-ambulatory patients, if they have no neurological impairment and are not an instability risk should have a unipolar hemiarthroplasty; the others in this class should have a bipolar hemiarthroplasty.

Internal fixation, unipolar, and bipolar hemiarthroplasty all have higher re-operation rates than does total hip arthroplasty. Internal fixation represents the most expensive of the four possible options, because of the relatively high rate of revision surgery required.