HIP Fracture Accelerated Surgical TreaTment And Care tracK (HIP ATTACK) Trial

Hip fractures have devastating consequences: the 30-day mortality rate for men is 9% and for women is 5%, and the risk of disability is substantial. Even among patients who are community-dwelling prior to their hip fracture, 11% are bed-ridden and 16% are in a long-term care facility after one year.

The trauma associated with a hip fracture results in pain, bleeding, and immobility. These factors initiate inflammatory, hypercoaguable, stress, and catabolic states that can cause medical complications, including death. Proposed mechanisms for increased mortality and morbidity associated with delayed surgery include 1) complications related to a protracted immobilization (e.g. venous thromboembolism, atelectasis and pneumonia, urinary tract infections, pressure ulcers, and muscle mass loss) and 2) increased cardiovascular events.

Delay in surgery may result in protracted immobility and the associated complications, as well as prolonged exposure to the hypercoagulable-inflammatory-sympathetic state which may increase cardiovascular events. Observational data suggests that these mechanisms are indeed important: delayed surgical repair is associated with increased mortality and morbidity after a hip fracture.

A systematic review and meta-analysis of observational studies addressed the impact of timing of surgery on the outcome after hip fracture. Five studies reported adjusted measures for mortality. The pooled estimate, based on 721 deaths in 4,208 patients, suggested that early surgical treatment (i.e. within the cut-off of the individual studies) of hip fractures was associated with a significant reduction in mortality (adjusted risk ratio [RR] 0.81, 95% confidence interval [CI] 0.68-0.96).

It is possible that these observational data substantially underestimates the real potential of early surgery. The reason is that the "early surgery" in these studies occurred within 24, 48 or 72 hours. If surgery could be uniformly undertaken within 6 hours, given the potential benefits of earlier mobilization and minimization of the period of the inflammatory hypercoagulable state, the benefits might be substantially greater. The substantial impact of treatment of acute myocardial infarction (MI) or stroke within hours adds credence to this possibility.

Despite the evidence, and the possibility that a larger effect might result from even earlier surgery, current data supports only weak inferences. The evidence relies on observational data and is therefore susceptible to residual confounding. The strength of inference from current evidence does not lay a sufficient solid base to justify the substantial system modification required to facilitate accelerated surgical access for all hip fracture patients.

The main factors that cause surgical delay after a hip fracture are: 1) the patient presents with comorbidities and surgery is deferred for preoperative diagnostics, risk stratification, and medical optimization ("medical clearance") and 2) surgical operating room and staff resources are not available because hip fractures have low priority in urgent surgery lists ("queuing"). Both medical clearance and queuing are modifiable issues - addressing these obstacles has the potential to substantially reduce surgical wait times.

Our ultimate goal is to undertake a large multicentre randomized controlled trial (RCT) of accelerated surgical care (i.e., goal of surgery within 6 hours of diagnosis) versus usual timing of surgery among elderly adults diagnosed with a hip fracture. This protocol is for a pilot RCT that will inform the feasibility of undertaking a large RCT.

Inclusion criteria

• aged ≥ 45 years AND
• diagnosed during working hours on week days with a hip fracture requiring surgery

Exclusion criteria

We will exclude patients based on the following criteria:

• patients requiring urgent surgery or urgent interventions for another reason (e.g., subdural hematoma, abdominal pathology requiring urgent laparotomy, acute limb ischemia, other fractures or trauma requiring urgent surgery, or necrotising fascitis; PCI; pacemaker-implantation);
• open hip fracture;
• patients refusing participation;
• patients previously enrolled in the study;
• Therapeutic anticoagulation not induced by warfarin or intravenous heparin.

Criteria in which the timeline of the surgery in the accelerated care group (after accelerated medical work-up) are at the discretion of the attending physicians.

• acute myocardial infarction associated with a mechanical complication (i.e., acute papillary muscle rupture, ventricular septal defect) or ST-elevation MI;
• cardiac arrest;
• cardiogenic shock, defined by systemic hypotension and symptoms of organ hypoperfusion (oliguria, change in mental status, cold extremities) that the treating physician believes is due to a low cardiac output state (measurement of cardiac index or pulmonary capillary wedge pressure is not required) or requiring inotropic drugs;
• frank pulmonary edema that cannot be corrected within 2 hours (i.e. after 2 hours the patient cannot maintain oxygen saturation ≥ 90% in supine position with nasal oxygen or 28% oxygen);
• respiratory failure requiring mechanical ventilation;
• known pulmonary artery hypertension (> 80 mm Hg);
• home oxygen therapy with concomitant non-warfarin full dose anticoagulation or clopidogrel (because regional anesthesia is not possible);
• presumptive bacteremia on the basis of fever ≥ 39° Celsius or two of the following: a) Temperature >38° Celsius or <35° Celsius; b) WBC >12 or < 4 or >10% immature bands; c) rigors; and d) hypotension with evidence of organ dysfunction;
• hereditary or acquired coagulopathy that cannot be corrected within 2 hours to a INR < 1.5,
• thrombocytopenia (platelets < 75) of unknown origin that cannot be corrected within 2 hours or in case of known chronic thrombocytopenia platelets < 50;
• deep venous thrombosis in the last month requiring implantation of vena-cava filter;
• acute stroke within 7 days of fracture;
• subarachnoid hemorrhage within 1 month of fracture;
• impaired consciousness of unknown origin (Glasgow coma scale < 12);
• fractures acquired during a seizure in patients without a known history of epilepsy;
• hyponatremia (< 120 mmol/L) or hypernatremia (> 155 mmol/L) or hyponatremia < 125 mmol/L or hypernatremia >150 mmol/L associated with severe neurological symptoms (impaired consciousness to coma, seizures);
• hyperkalemia > 5.5 mmol/L with QRS-complex > 120 milliseconds (in patients without known previous QRS-complex > 120 ms) or hypokalemia < 2.8 mmol/L not amenable to correction within 2 hours;
• known pH < 7.15 not amenable to correction within 2 hours; or
• indication for acute dialysis.