The origin of sharp, radiating pain in the hip joint can be local or referred from the low back. In a 1999 article in the "American Family Physician," Dr. John O'Kane notes that diagnosis can be a challenge because "Pathologic conditions ranging from a benign muscle or tendon strain to a potentially catastrophic femoral neck stress fracture can have similar clinical presentations."
The syndrome occurs when the piriformis muscle, situated at the back of the hip, compresses the sciatic nerve. The result is severe pain both in the joint and along the course of the sciatic nerve at the back of the leg. In some cases, pain may extend as far as the calf and the foot. The syndrome is uncommon and can be difficult to differentiate from nearly identical symptoms caused by compression of the sciatic nerve at its origin in the spinal cord.
Large muscle groups originate in the hip and extend to the knee. When a thigh muscle sustains a strain such as a severe bruise or tear, the distribution of pain occurs in the joint and along the muscle. An example is a torn hamstring, a common sports-related injury.
Inflammation of the trochanteric bursa, a fluid-filled cushion that reduces friction between moving structures in the joint, results in hip pain radiating into the thigh. Any action that increases pressure on the bursa, such as lying on the affected hip or walking, intensifies the pain. According to the American Academy of Orthopaedic Surgeons, bursitis can affect anyone, but is more common in women, middle-aged men and the elderly.
The degeneration of cartilage and the bony changes that occur in osteoarthritis are usually caused by the wear of aging joints. Weight-bearing joints like the hips are particularly at risk. In advanced cases, the degeneration can cause debilitating pain in the joint and thigh.
The MayoClinic.com notes that the joint most affected by osteonecrosis is the hip. When the blood supply to the ball of the joint is damaged, usually because of a fracture or dislocation, bone cells die. Pain in the hip and leg can become debilitating as the deterioration of bone progresses. As in advanced osteoarthritis, osteonecrosis may lead to hip replacement surgery.
The AAOS states that transient osteoporosis which primarily affects pregnant women after the sixth month and middle-aged men causes sudden onset of pain radiating into the front of the thigh. Unlike other forms of osteoporosis, the condition is reversible.
Hip fractures occur in the upper quarter of the femur or thighbone where it meets the pelvis. The result is intense pain over the joint radiating into the upper thigh. Hip fractures due to falls and conditions such as osteoporosis occur frequently in the elderly. The consequences are potentially devastating for this age group, many of whom may never recover fully from the injury.