The clinical diagnosis of a displaced hip fracture is often readily apparent due to the so-called down and out posture, with the affected limb being shortened and externally rotated. In nondisplaced fractures there may not be an obvious deformity. The diagnosis in such cases is made based on the history of fall (a single fall) and subsequent inability to bear weight, as well as pain when the hip is moved either actively by the patient or passively by the examining clinician.
Routine radiographs of the hip, usually taken in two views (front and side) are sufficient to confirm the diagnosis. Occasionally a fracture may not be apparent radiographically, so if the clinical suspicion is strong, further investigations should be carried out. Radionuclide imaging with technicum bone scanning is most commonly used, but even with this tool diagnosis can be difficult. Particularly in an elderly person, a fracture may not become apparent on bone scan for two to five days after an injury. More recently, MRI has been shown to be more accurate and, if hospitalization of the patient is required, more cost effective. These techniques would only be used in the exceptional case where the diagnosis is not clear. For example, metastatic cancer frequently affects the proximal femur. Specific attention to bone quality on the radiograph is required to detect an occult lesion indicating a pathologic fracture. (A fracture through abnormal quality bone, generally a metastatic diseased bone. Certain cancers commonly metastasize to the proximal femur, especially lung, breast, prostate, thyroid and renal cancers.) The likely primary cancer sites are breast, lung, prostate, thyroid, and kidney.