A hip fracture is a large burden to the patient with increased mortality, pain and increased need for daily assistance. Trochanteric fractures of the femur (FTF) represents about 35% of the hip fractures. Today FTFs are mainly treated with internal fixation using sliding hips screws (SHS) or intramedullary nail (IMN), whilst hip arthroplasty (THA/HA) is rarely used. Despite advances in the design of the internal fixation implants there is a high failure rate, in particular in cases of FTFs classified as unstable fractures. Since the introduction of hip arthroplasty in femoral neck fractures there has been a reduction in complication rates, early mobilization and shorter hospital stays.

The primary objective of this project is to investigate if treatment with hip arthroplasty in unstable FTFs will increase the postoperative mobility, give a better general health outcome for the patient, better quality of life and reduce re-operation rate for the patients compared to those operated with the traditional IMN.

Proximal femoral fractures also termed "hip" fractures are one of the most common fractures among adults over 50 years of age. With increase in life expectancy, the incidence of these fractures is also increasing. By 2040, the number of these fractures are expected to double in Norway. Trochanteric fractures of the femur (Fractura Trochanterica Femoris, FTF) represents about 35% of the hip fractures in Norway . There are many classification systems for FTFs, but The Orthopaedic Trauma Association (OTA) have adopted the system developed by the Arbeitsgemeinschaft Osteosynthese (AO ) group, and is the most commonly used in addition to the Evans Jensens classification.

The mean age of hip fracture patients is 82 years for women and 78 for men. The comorbidity in this patient group is high with large amount of dementia, sarcopenia and osteoporosis. The one-year mortality rate after a hip fractures is 20-35%. According to the Norwegian Hip Fracture Register 15 % of the hip fractures are unstable trochanteric fractures (AO 31A2.2-A3). The prognosis is poor, in particular for unstable (multi fragmented) fractures, with reported complications up to 35-51 %.

Substantial research has established better understanding and best practice guidelines to treat the femoral neck fractures, mostly with hip arthroplasty, however no superior method is established for the unstable trochanteric fractures. 'Getting It Right First Time' is important for these fragile patients, thus post-operative complications are associated with a large increase in the mortality.

Today, most of the FTFs are reduced and fixated with a sliding hip screw (SHS), although the use of intramedullary nails (IMN) is increasing. RCTs have shown better survival of IMN compared to SHS for the more distal FTFs and subtrochanteric fracture. Unstable FTFs (AO 31A2 - A3, EVJ III-V) have high reoperation rates (21-35%) when operated either with SHS or IMN. Unacceptable shortening, external rotation deformity of the limb and long time to recover/mobilization have been the problems with osteosynthesis.

The question is if hip arthroplasty can give a superior treatment outcome for patients suffering from unstable subtypes of trochanteric hip fractures compared to the traditional treatment with IMN. A randomized clinical trial is to be conducted comparing these two treatment methodologies.

Stavanger University Hospital (SUH) receives over 150 FTFs per year. About 1/3 of the FTFs are of unstable fracture morphology. The planned study is a randomized clinical trial. The randomization module will be provided by Klinisk forskningsenhet Midt-Norge (KlinForsk). Patients fulfilling the inclusion criteria will be randomized to one of two treatment groups, IMN versus hip arthroplasty.

Included patients will be treated in accordance to a local operation protocol:

Intramedullary nails will be operated by a resident orthopedic surgeon with at least 2 years' experience in fracture surgery or a consultant orthopedic surgeon (there must always be a consultant orthopedic surgeon present in the surgical team). A long IMN must always be utilized. Anatomical reposition or positive anterior and medial cortical support should be strived to be achieved. If a large antero- or posteromedial fragment is present one should consider an additional cerclage to fix the fragment.

Arthroplasty will be operated by a resident orthopedic surgeon with at least 2 years' experience with hip arthroplasty surgery or by a consultant orthopedic surgeon subspecialized in arthroplasty surgery, with competency within revision or difficult primary hip arthroplasty surgery (there must always be a consultant orthopedic surgeon subspecialized in arthroplasty surgery present in the surgical team). Posterior surgical approach will be used. If a cup is to be utilized it must be a cemented dual-mobility cup.

The patients will have follow-up appointments at 2-, 6 and 12 months postoperative. Following data will be collected:

• Patient reported outcome measures (HOOS and EQ5D)
• Timed up and go test
• Trendelenburg test
• Clinical leg length discrepancy
• Radiological assessment from hip x-rays (AP and lateral)

Inclusion Criteria:

• Age ≥ 65 years
• American Society of Anesthesiology Score (ASA) < 4
• Ambulant with or without aid (preinjury)
• Radiological verified unstable trochanteric hip fracture (AO 31A2.2 - 3.3)
• Written consent obtained by patient or his/her next of kin

Exclusion Criteria:

• Previous hip surgery on ipsilateral or contralateral side
• Non-ambulant preinjury
• Patient not living in the area of hospital care