Thigh root pain is not necessarily femoral head necrosis, it may also be hip bursitis, osteoarthritis, loose prosthesis, etc. 1. Bursitis: In patients with femoral head necrosis, the main cause is increased pressure on the femoral head, while thigh pain is caused by increased pressure on the thigh, which in turn leads to hip pain and radiating pain sensation at the thigh root. The most common is hip bursitis, including greater trochanteric bursitis and pubic bursitis. 2. Osteoarthritis: pain may also occur in osteoarthritis, such as inflammatory arthritis, septic arthritis, dislocation or subluxation. 3. Loose prosthesis: If you have had a hip joint before, thigh root pain may also occur if there is loosening of the prosthesis. There are many factors leading to thigh root pain, patients should seek timely medical treatment, under the guidance of professional doctors, the correct treatment.