Femoroacetabular impingement (FAI)
Active adults roughly 18 to 50, especially those who played hockey, soccer, basketball or dance as teensIn FAI, extra bone on the ball (cam type) or on the rim of the socket (pincer type) makes the two bump together when the hip bends and turns. Over time that repeated contact can fray the labrum and the cartilage at the edge of the socket. Many people have the bone shape without pain; it becomes a problem when it starts causing symptoms.
The clue: A sharp pinch in the groin when the knee is pulled toward the opposite shoulder, as in getting out of a car, is the classic clue.
Hip labral tear
Runners, golfers, dancers, yoga practitioners and anyone with FAI or a shallow hip socketThe labrum is a rim of cartilage around the hip socket that deepens it and helps seal the joint. It can tear from impingement, a twisting injury or gradual wear. A torn labrum often causes a deep groin ache plus moments of sharp catching.
The clue: Clicking, locking or a catching sensation deep in the hip with pivoting movements points toward the labrum.
Hip osteoarthritis
Adults over 50, and younger adults with past hip injury, FAI or hip dysplasiaOsteoarthritis is the gradual loss of the smooth cartilage that lines the ball and socket. The joint gets stiff, loses rotation and aches with weight bearing. It tends to progress slowly over years, with good and bad stretches along the way.
The clue: Groin pain with stiffness first thing in the morning and growing trouble with socks, shoes and toenails is typical.
Hip dysplasia
Women in their teens to 40s, and people with a family history of shallow hip socketsIn hip dysplasia the socket is too shallow to fully cover the ball. The edge of the socket and the labrum carry too much load, which can lead to pain, a labral tear and early arthritis. Mild dysplasia often goes unnoticed until adulthood.
The clue: Groin pain with a sense that the hip is unstable or tired after standing, in a flexible young adult, suggests dysplasia.
Hip flexor (iliopsoas) tendinitis or adductor strain
Runners, cyclists, soccer players and anyone who recently increased kicking, sprinting or hill workThe iliopsoas tendon crosses the front of the hip and the adductor muscles attach high on the inner thigh. Overuse can irritate either one. These are muscle and tendon problems rather than joint problems, and they usually settle with rest and progressive strengthening.
The clue: Pain lifting the leg against resistance, or tenderness right where the inner thigh meets the pelvis, points to the tendon or muscle.
Femoral neck stress fracture
Distance runners, military recruits and women with low bone density or low energy intakeRepeated impact can cause a small crack in the neck of the thighbone, just below the ball. It may not show on X-rays early on, so an MRI is often needed. Some stress fractures need protected weight bearing and others need surgery to prevent a complete break.
The clue: Groin pain that builds during every run and starts to hurt with ordinary walking needs prompt imaging.