What Causes Pain on the Outer Side of the Thigh?

Pain on the lateral aspect of the upper thigh (groin region) is most commonly caused by lumbar disc herniation, but may also result from acetabular dislocation or, more frequently, from chronic overuse injuries such as gluteus medius syndrome or piriformis syndrome.

Trochanteric bursitis occurs on the lateral side of the hip, at the site of the trochanteric bursa located over the greater trochanter of the femur. It is typically an aseptic inflammatory condition caused by repetitive friction or prolonged lateral sleeping position. The pain is usually localized and accompanied by marked tenderness. Swelling may occur, leading to loss of the normal contour or depression in this area. Pain may lessen when the leg is abducted.

Avascular necrosis (AVN) of the femoral head is a pathological condition characterized by disruption of blood supply to the femoral head—due to various etiologies—leading to ischemia, bone cell death, trabecular microfractures, and eventual collapse and deformity of the femoral head. This ultimately progresses to osteoarthritis of the hip joint and functional impairment. Pain is typically localized to the buttock and lateral thigh, and may even radiate to the knee. In some cases, pain may be felt on the medial aspect of the hip, though this is relatively uncommon.