Each year, hip fracture, an injury that can impair independence and quality of life, occurs in about 280,000 Americans and 36,000 Canadians. By the year 2040, the annual healthcare costs associated with hip fractures are expected to reach $9.8 billion in the United States and $650 million in Canada. It is important to have in place optimal practice guidelines for the surgical handling of this injury. One type of hip fracture, called a displaced femoral neck fracture, is often treated with a hip replacement surgery. Patients undergoing a hip replacement may receive either a total hip replacement, in which the head of the femur and the hip joint socket are replaced, or a partial hip replacement, in which only the head of the femur is replaced. This study will compare the two different hip replacement procedures to determine which one results in better outcomes after surgery in adults aged 50 and older.

One type of hip fracture, called a femoral neck fracture, involves a break in the narrow part of the femur bone where the head of the femur is joined to the main shaft. The break can be either undisplaced, which involves very little separation at the fracture site, or displaced, in which there is substantial separation. For displaced fractures, surgeons usually choose between internal fixation and hip arthroplasty, which is also known as hip replacement.

Patients receiving hip arthroplasty may undergo either a total hip arthroplasty or a hemi-arthroplasty. Which surgical method is best for the patient is unknown. Advocates of total hip replacement claim better improvements in patient function and quality of life. On the other hand, advocates of hemi-arthroplasty, which include most orthopaedic surgeons, claim reduced rates of dislocation and deep vein thrombosis, shorter operating times, less blood loss, and a technically less demanding surgical procedure. This study will compare total hip arthroplasty and hemi-arthroplasty on rates of revision surgery 2 years after patients aged 50 and older sustain femoral neck fractures and undergo surgery. The study will also compare the impact of the two different surgical procedures on function, quality of life, and post-surgical complications. Results from this study may impact current orthopaedic practice.

Participation in this study will last 2 years. Before surgery, participants will complete a baseline assessment that will include x-rays, a medical history review, and a physical examination. Participants will then be randomly assigned to undergo either total hip arthroplasty or hemi-arthroplasty to repair their hip fractures. All surgeons will need to meet certain criteria to partake in the study and will have expertise in whichever surgical procedure they are performing. Surgeons will also follow the manufacturers' implant guidelines during surgery. Specific aspects of both the preoperative and post-operative care, such as weight bearing status, the prevention of thromboembolic disease, and the use of antibiotics and calcium supplementation, will be standardized for all participants. Within 2 days of under going surgery, x-rays will be performed again.

Follow-up assessments will be completed either by phone or in-person at the hospital or clinic. They will occur 1 and 10 weeks after surgery and 6, 9, 12, 18, and 24 months after surgery. All assessments will include questionnaires and interviews on health status, hip function, pain, functional mobility, and revision surgery. Some of the in-person assessments will also include x-rays.

Inclusion Criteria:

• Adult men or women aged 50 years and old (with no upper age limit)
• Fracture of the femoral neck, as confirmed with either anteroposterior or lateral hip radiographs, computed tomography, or magnetic resonance imaging (MRI)
• Displaced fracture that is not, in the judgment of the attending surgeon, optimally managed by reduction and internal fixation
• Operative treatment is planned within 72 hours of the patient being medically cleared for surgery
• Patient was ambulatory prior to the fracture, though they may have used an aid such as a cane or a walker
• Anticipated medical optimization for arthroplasty of the hip
• Provision of informed consent by patient or proxy
• Low energy fracture (defined as a fall from standing height), with no other trauma
• Assurance from site that surgeons with expertise in both total hip arthroplasty and hemi-arthroplasty are available to perform surgery (Note: Surgeons do not need to be experts in both techniques)

Exclusion Criteria:

• Not suitable for hemi-arthroplasty (i.e., inflammatory arthritis, rheumatoid arthritis, pathologic fractures (secondary to cancer), or severe osteoarthritis of the hip)
• Associated major injuries of the lower extremity (e.g., ipsilateral or contralateral fractures of the foot, ankle, tibia, fibula, knee, or femur; dislocations of the ankle, knee, or hip; or femoral head defects or fracture)
• Retained hardware around the affected hip that will interfere with arthroplasty
• Infection around the hip (soft tissue or bone)
• Bone metabolism disorder except osteoporosis (e.g., Paget's disease, renal osteodystrophy, osteomalacia)
• Patients with a previous history of frank dementia that would interfere with the assessment of primary outcome (e.g., secondary procedures at 2 years).
• Likely problems, in the judgment of the investigators, with maintaining follow-up (e.g., no fixed address, plans to move out of town in the next year, or intellectually challenged and without adequate family support)
• Enrolled in another ongoing drug or surgical intervention trial
• Patients whose fracture occurred as a result of violence.