The systematic review "Treatments of Common Hip Fractures," completed in August 2009, was the result of a topic nomination made by the American Academy of Orthopaedic Surgeons, who were planning to formulate clinical guidelines for surgical procedures for implantable devices. The nominator was interested in understanding the interaction between patient factors, fracture types, types of surgical implants, and outcomes. Following refinement, the key questions addressed were: Key Question 1. What is the relationship between patient variables (e.g., demographic factors, comorbidities), the type of fracture (i.e., intertrochanteric, subtrochanteric, subcapital) and post-treatment outcomes (e.g., pain, mobility, mortality)? Key Question 2. What is the relationship between the type of fracture (i.e., intertrochanteric, subtrochanteric, subcapital) and post-treatment outcomes (e.g., pain, mobility, mortality)? Key Question 3. What is the relationship between implant variables (e.g., position, material, method, and design of implant) and patient posttreatment outcomes (e.g., pain, mobility, mortality)? Key Question 4. What is the relationship between the type of intervention (e.g., internal fixation versus arthroplasty) and patient post-treatment outcomes (e.g., pain, mobility, mortality)? The systematic review was unable to fully answer the research questions with the existing literature generally because of two main factors: (1) the limited perspective of discipline-specific investigations (i.e., orthopaedics or epidemiology), which tended to use incomplete sets of important independent variables in study designs and models, and (2) the generally low quality of hip fracture outcome studies to date, where specific populations were poorly defined, and the use of inconsistent outcome variables prevented aggregating or even comparing results. The latter problem of inconsistent outcomes measures is a general issue for most mobility literature. Additionally, very little literature was available to provide evidence for the multitude of comparisons of device variables within a class of devices, i.e. number of screws or the specific design for sliding hip screw implants. With this inability to show either greater effectiveness or equivalency between device variables, or between devices within a class, aggregating the comparisons at the level of head to head comparisons of classes of devices becomes problematic.