Clinical research during the last ten years has revealed that elderly patients with a displaced femoral neck fracture should be treated with arthroplasty instead of closed reduction of the fracture followed by internal fixation with pins or screws. Few clinical trials have addressed undisplaced or minimally displaced fractures of the femoral neck. These fractures have been associated with a good prognosis and likewise a good functional outcome. However, recent articles present far less favorable results, with high re-operation rates (10-15%), reduced function, and pain on walking after internal fixation. Indirect comparing studies, suggest that hemiarthroplasty may yield better functional outcomes and lower re-operation rates. Approximately 20% of all femoral neck fractures in patients aged 70 years or older are minimally displaced or undisplaced. Hence the investigators call for a randomised controlled trial comparing pain, function, walking ability, quality of life, re-operation rates and complications after internal fixation versus hemiarthroplasty in patients aged 70 years and older.

The consequences of a femoral neck fracture still have a substantial impact on the individual patient´s health as well as on society. Approximately 5000 individuals suffer a fracture of the femoral neck annually in Norway. The mortality rate approximates 25% during the first year after this injury. The hospital costs of treating a single femoral neck fracture, have been estimated to 20 000 euros.

In spite of relatively well-documented treatment protocols, there is still a need for prospective randomised controlled trials to determine the optimal treatment of certain sub-groups of patients presenting with a femoral neck fracture.

Several studies with a high level of evidence have elucidated management of displaced femoral neck fractures. There is increasing evidence favouring joint replacement surgery over internal fixation when treating displaced femoral neck fractures. However, management of undisplaced and minimally displaced femoral neck fractures has received less attention.

According to the Cochrane Library, there are no randomised controlled trials comparing internal fixation to hemiarthroplasty in patients with undisplaced femoral neck fractures. Previous studies have focused mostly on fracture healing, equating fracture union and success. However, recent studies report decreased functional and life quality scores amongst patients with undisplaced femoral neck fractures treated with internal fixation. The control group in these studies consists of patients with a displaced femoral neck fracture treated with hemi - arthroplasty. Zlowodzki et al showed, by means of validated assessment scores, that patients with internally fixated undisplaced femoral neck fractures often experience shortening of the injured limb. Then again, this is associated with lower functional and life quality scores. In Rogmark´s series of patients with undisplaced femoral neck fractures treated with internal fixation, 25% patients report daily pain from the affected hip upon walking, one and a half year after surgery. Gjertsen et al analysed data for the Norwegian hip fracture registry from more than 4000 patients to demonstrate that treatment with hemiarthroplasty, due to a displaced femoral neck fracture, is associated with better function and less pain than treatment with internal fixation due to an undisplaced femoral neck fracture.

Thus, our research group will conduct a prospective randomised controlled trial to identify any differences in clinical outcome after surgical treatment of undisplaced femoral neck fractures in patients aged 70 years and older. The two methods that will be compared are internal fixation with two screws and modern modular hemiarthroplasty. The primary outcome measure is a difference of at least 10 points in Harris Hip Score (95% power, standard deviation approximates 15 points from previous Norwegian patient series). The primary follow-up length is set to two years, but a long-term follow-up five years after surgery is also planned. It is important to include the cognitively impaired patients as they account for 20-25% of the study population. Patients who cannot provide informed consent due to impaired cognitive function, are included if consent is provided by a family member or relative.

Inclusion Criteria:

• Age 70 years or older
• Undisplaced or minimally displaced intracapsular femoral neck fracture (Garden I/II)
• Patient able to walk before injury (all aids allowed)
• Patient lives within the catchment area of the three involved centres

Exclusion Criteria:

• Displaced fractures (Garden III/IV) and impacted fractures with minimal varus
• Pathologic fracture
• Current soft tissue or deep infection in the hip or pelvis area
• ASA IV patients as classified by the anesthesiologist on call
• Other contraindications to either of the two methods compared
• Temporarily impaired cognitive function:

(That is when the patient is judged as unable to provide an informed consent by the surgeon on call and there is no previous history of impaired cognitive function as documented by previous hospital record or a family member / proxy)

Data planned published in English in a peer-reviewed medical journal