Hip Fractures:

Typically divided into four types:

1. Intracapsular,
   1. femoral head and neck fractures
2. Extracapsular
   1.  trochanteric,
   2. Intertrochanteric
   3. subtrochanteric fractures. 

• Non-displaced fractures, especially in osteoporotic elderly patients, may be missed on plain films. This is estimated to occur in 2-9% of cases. 
• It can take up to 72 hours for a fracture to be seen on bone scan. And it is estimated that only 80% of fractures will be seen at 24 hours.
• MRI is now the preferred imaging modality (100% sensitivity and specificity) to confirm a hip fracture when plain films are negative and equivocal. A MRI will have positive findings in as little as 4 hours after a fracture.
• Consider CT scan of the hip if MRI is not available at your center.

Here is a link to a picture with a good representation of the different types of fractures.

References

Perron A.D., Miller M.D., Brady W.J. Orthopedic pitfalls in the ED: Radiographically occult hip fracture. Am J Emerg Med 2002;20:234-237.