This is an extremely overused area of the body; therefore injuries tend to more along the line of overuse in terms of onset. Common pathology affecting this area would be osteoarthritis of the hips.
Ultimately it is an area, as it the shoulder that has to be controlled equally from the rear as from the front in order to work properly and for the mechanics of the joint to remain equal, much as the tracking of a cars wheels would. The vast amount of soft tissue and nervous tissue around the hip and thigh does mean that it is prone to overuse and underuse conditions. Examples would be bursitis of the hips, impingement of the hip or simple nerve irritation. Depending on the activity, cause and person involved would influence the type, amount and level of rehab/ treatment required.