Fixation Using Alternative Implants for the Treatment of Hip Fractures (FAITH-2)

Femoral neck fractures are a type of hip fracture associated with high complication rates and
poor functional outcomes. It is estimated that over 300,000 hip fractures occur in patients
under age 50 annually. Hip fractures in younger aged patients are particularly devastating
with profound impairments of quality of life and function. Virtually all patients require
surgical repair of their fractures and unlike elderly hip fractures, failure of surgery
offers few options for salvage. Arthroplasty is a successful treatment for elderly patients;
however, a hip replacement is not a viable option for younger patients because of their
higher functional demands for work and recreational activities that are not tolerated by
joint replacements.

There is more than one way to perform internal fixation for femoral neck fractures.
Cancellous screws have traditionally been the preferred internal fixation implant for femoral
neck fractures. Multiple screws (2 or more) are used during fixation, and advocates of this
implant promote the construct's superior torsional stability, limited disruption of femoral
head blood supply, minimally invasive insertion, and retention of more viable bone than the
larger sliding hip screw (SHS). On the other hand, sliding hip screws have been gaining
popularity and there is evidence to suggest that SHS provide greater fracture stability and
may reduce patient complications. It is currently unknown which method of internal fixation
provides the best outcomes for patients.

Femoral neck fracture treatment is further complicated by vitamin D insufficiency in as many
as 8 of 10 trauma patients. Vitamin D plays an important role in musculoskeletal health and
bone quality because it regulates serum calcium homeostasis. Laboratory research and human
clinical studies suggest important associations between vitamin D, musculoskeletal health,
and improved fracture healing. Experimental animal studies have demonstrated the
concentration of vitamin D metabolites are higher at a fracture callus compared to the
uninjured contralateral bone, vitamin D supplementation leads to decreased time to fracture
union and increased callus vascularity, and vitamin D increases mechanical bone strength
compared to controls. Clinical studies have also demonstrated that vitamin D supplementation
increases the callus volume of proximal humerus fractures, increases the number and diameter
of type II muscle fibres, and can improve wound healing, however, the effects of vitamin D
supplementation in you patients with femoral neck fractures are unknown.

Using a 2x2 factorial design, participant will be randomly allocated to one of four treatment
arms. Participants allocated to the cancellous screw group will receive multiple threaded
screws (with a minimum of 3 screws and a minimum diameter of 6.5 mm) and those allocated to
the sliding hip screw group will receive a single larger diameter partially threaded screw
affixed to the proximal femur with a sideplate using a minimum of 2 screws for fixation.
Participants allocated to the vitamin D Group will receive a bottle of 2,000 International
Units (IU) vitamin D3 drops. Participants will be instructed to take two drops daily for six
months, for a total daily dose of 4,000 IU. Participants in the placebo group will receive an
identical bottle of placebo drops with no active ingredient. Similarly, they will be
instructed to take two drops daily for six months. All vitamin D3 supplement and placebo
bottles will be labeled in a blinded manner according to Health Canada and Good Manufacturing
Practice.

Participation in this study will last 12 months. In-person participant follow-up visits will
occur at enrollment (baseline), post-surgery, 6 weeks, 3 months, 6 months, 9 months, and 12
months post-surgery. Data for all outcomes and radiographs will be collected at each
follow-up visit.

Inclusion Criteria

1. Adult men or women ages 18 to 60 years.

2. Fracture of the femoral neck.

3. Fracture amenable to both surgical treatments (SHS and cancellous screws).

4. Operative treatment within 7 days of injury.

5. Provision of informed consent by patient or substitute decision maker.

Exclusion Criteria

1. Patients with previously diagnosed osteoporosis.

2. Fracture-dislocation of the femoral neck and hip joint.

3. Planned antegrade nailing of an ipsilateral femoral shaft fracture (if present).

4. Current infection around the hip (i.e. soft tissue or bone).

5. Stress fracture of the femoral neck.

6. Pathologic fractures secondary to neoplasm or other bone lesion.

7. Patients with known or likely undiagnosed disorders of bone metabolism such as Paget's
disease, osteomalacia, osteopetrosis, osteogenesis imperfect, etc.

8. Patients with hyperhomocysteinemia.

9. Patient has an allergy to vitamin D or another contraindication to being prescribed
vitamin D.

10. Patient is currently taking an over counter drug and/or food supplement that contains
vitamin D and is unable or unwilling to discontinue its use for this study.

11. Likely problems, in the judgment of the attending surgeon, with maintaining follow up
(e.g. patients with no fixed address, plans to move out of town). This may include
patients with severe mental disorders and drug addictions without adequate support.

12. Pregnancy.

13. Patient is incarcerated.

14. Patient is not expected to survive injuries.

15. The attending surgeon believes the patient should be excluded because they are
involved in a conflicting clinical trial.