Fixation using Alternative Implants for the Treatment of Hip Fractures.

SUMMARY OF RESEARCH PROPOSAL




Rationale

Hip fractures occur in 280,000 Americans (over 5000 per week) and 36,000 (over ? per week) Canadians annually. The number of hip fractures is likely to exceed 500,000 annually in the United States and 88,000 in Canada. The estimated annual health care costs will reach a staggering $9.8 billion in the United States and $650 million in Canada. Hip fractures are associated with a 30% mortality rate and profound temporary and sometimes permanent impairment of independence and quality of life. Worldwide, 4.5 million persons are disabled from hip fractures yearly with an expected increase to 21 million persons living with disability in the next 40 years. Experimental data suggest that cancellous screws offer greater preservation of blood and supply, while sliding hip screws provide greater biomechanical stability to bending stresses. While both arguments are persuasive, the impacts of these biologic alterations on outcomes that are important to patients offer more compelling guidance for clinical practice




Need for a Definitive RCT

We summarize the rationale for the trial below. First, although current opinion among orthopaedic surgeons favors the use of cancellous screws over sliding hip screws, there remains sufficient divergence in perceptions and sufficient interest to resolve this issue to warrant a large RCT. Second, despite the popularity of cancellous screw fixation, there is a strong biologic rationale supporting the sliding hip screws, a more biomechanically stable construct, in older patients with osteopenia/osteoporosis. Third, while our meta-analyses provide indirect and direct evidence that a sliding hip screw may revision surgery rates, the evidence remains far from definitive. The current best estimate of treatment effect with sliding hip screws is based upon small trials with methodologic limitations including unconcealed randomization and lack of blinding. The resulting estimates include wide confidence intervals (i.e., displaced fractures: RRR=27%, 95%CI: 48%, -4%, P=0.08 and 4). Whatever approach to internal fixation proves best, a large proportion of patients will continue to need revision surgery that is associated with high morbidity and appreciable mortality.




Objective

To assess the impact of sliding hip screws versus cannulated screw fixation on rates of revision surgery at 2 years in individuals with femoral neck fractures. We secondarily aim to determine the impact on health-related quality of life (Short Form-12, SF-12), functional outcomes (Western Ontario McMaster Osteoarthritis Index, WOMAC), and health utility (Health Utilities Index Mark III, HUI3).




Hypothesis

We hypothesize that sliding hip screws will have lower rates of revision surgery (primary outcome) and higher functional outcome scores (secondary outcome) at 24 months compared with cancellous screws.




Study Design

We propose a multi-centre, concealed randomized trial design using minimization to determine patient allocation. Surgeons across Canada, United States, South America, Europe, Australia, and Asia will participate. Surgeons will use one of two surgical strategies in 2,500 patients who have sustained a femoral neck fracture. The first strategy involves fixation of the fracture with multiple small diameter cancellous screws (i.e., Cancellous Screw Group). The second treatment strategy involves fixation of the fracture with a single larger diameter screw with a sideplate (i.e., Sliding Hip Screw Group). Study personnel will monitor critical aspects of peri-operative care and rehabilitation for protocol deviations. We will independently adjudicate revision surgery rates at discharge, 2 weeks, 10 weeks, 3 months, 6 months, 9 months, 12 months, 18 months, and 24 months post surgery. The primary outcome is revision surgery within 2 years of surgery. The secondary outcomes include patient quality of life (Short Form-12, SF-12), function (Western Ontario McMaster Osteoarthritis Index, WOMAC), and health utility (Health Utilities Index Mark III, HUI3). We will independently adjudicate revison surgery rates at regular intervals up to 2 years.




Potential Impact of Study

This trial will not only change current orthopaedic practice, but will set a benchmark for the conduct of future orthopaedic trials.

We hypothesize that sliding hip screws will have lower rates of revision surgery (primary outcome) and higher functional outcome scores (secondary outcome) at 24 months compared with cancellous screws.

Baseline, operation, 2 and 8 weeks, 6-9-12-18-24 months.

1. Internal Fixation;

2. DHS versus cannulated screws.