Greater trochanteric pain syndrome
Women over 40, runners and people who sleep on their sideLying on the painful side presses the gluteal tendons and bursa against the bony point of the hip. Lying on the other side lets the top leg drop across the body, which squeezes the tendon too. This is the most common cause of outer hip pain at night.
The clue: Pain on the outside of the hip when lying on either side, relieved by lying on the back, points here.
Advanced hip osteoarthritis
Adults over 55 with established hip arthritisEarly arthritis hurts mostly with activity. As it advances, the joint can ache at rest and at night. Night pain that regularly disturbs sleep is one of the signs that arthritis is significantly affecting quality of life.
The clue: A deep groin ache at night in someone with daytime stiffness and trouble with socks suggests arthritis.
Lumbar spine problems
Adults with disc disease or spinal stenosisPinched nerves and arthritic spinal joints can cause buttock and leg pain that worsens when lying flat or in certain positions. Patients often blame the hip. A spine exam helps sort this out.
The clue: Night pain in the buttock or leg that shifts with changes in back position suggests the spine.
Labral tear or FAI
Active adults roughly 20 to 50Sleeping with the knees pulled up and the leg rolled inward can pinch the front of the hip. A torn labrum can ache after a day of activity. Night pain is usually milder than in arthritis.
The clue: Waking with a deep groin ache in a curled-up sleeping position, in a younger active adult, suggests impingement.
Stress fracture or osteonecrosis
Runners and people with steroid use, heavy alcohol use or sickle cell diseaseA stress fracture of the femoral neck or loss of blood supply to the ball of the hip can cause aching that continues at rest and at night. Both may not show on early X-rays. An MRI makes the diagnosis.
The clue: Groin pain that started with running or without injury and now persists at rest needs an MRI.