Unipolar vs Bipolar Hemiarthroplasty for Hip Fracture

Proposed study design

Randomized controlled trial of unipolar vs bipolar hip hemiarthroplasty for intracapsular fracture of the femoral neck

The trial will be conducted in accordance with the GCP (Good Clinical Practice) guidelines and will be reported in line with the CONSORT statement

Study Centre

The Royal Infirmary of Edinburgh admits 1000 patients a year with a hip fracture; the largest number in any one centre in Scotland. Of these, 500 have intracapsular fractures, which is the type addressed in this study. Some patients will be better suited to a total hip replacement (5-10% of this group), and others may refuse to consent to the trial (previous experience has suggested a rate of 15-20%). Investigators therefore expect just over 300 patients to be recruitable each year, and so plan to allow up to two years for recruitment, and two years to complete follow up of the last patient

Brief Study Method

1. Patients will be identified as requiring a hemiarthroplasty for an intracapsular fracture of the femoral neck
2. Patients will be asked to consent to recruitment to study. Consent by attorney or nearest relative for patients with cognitive impairment
3. Surgery performed via anterolateral approach on standard trauma list. Standard cemented stem implanted.
4. Patient randomized in theatre to receive a unipolar or bipolar hemiarthroplasty head.
5. Tantalum beads will be implanted within the bone of the femur and pelvis (not the hip joint) by a consultant surgeon investigator when operating or assisting personally. These will not implanted where an unsupervised trainee is performing surgery. Fifty patients in each group will have these implants.
6. Patients undergo standard rehabilitation: physiotherapy, occupational therapy and geriatrician services as required.
7. Standard pre-op, post-op and one-year and two-year plain pelvic radiographs will be obtained.
8. Subset of patients: Fifty patients who have received a bipolar hemiarthroplasty will be asked to undergo one additional x-ray of the hip at two years to assess the function of the device.
9. Functional assessment: patients will undergo the Timed up-and-go (TUG) test, physiological measurements of hip muscle recruitment and function, and standardized questionnaires (SF12 and Harris Hip score).

Power analysis and number of patients

200 patients in each arm of study (total 400) allowing for expected 27% mortality at one year.

DMC (Data Monitoring Committee)

A data monitoring committee will review the results during the study period to allow the project to be terminated if statistical significance is reached or if there are any untoward events.