Hip Osteoarthritis

Hip osteoarthritis (OA) is a whole-joint disease that causes groin pain, stiffness, reduced walking distance and progressive loss of function, and it is a leading cause of hip replacement.

It is more common in women and becomes more common with age. Current NICE osteoarthritis guidance makes it a clinical diagnosis in people aged 45 or over with activity-related joint pain and either no morning stiffness or stiffness lasting no longer than 30 minutes.

The hip is a ball-and-socket synovial joint, deepened by the labrum and stabilised by a strong capsule and ligaments. It is supplied by the femoral, obturator and sciatic nerves (Hilton's law), which explains pain felt in the groin, anterior and medial thigh, buttock and knee.

OA affects the whole joint:

• •Cartilage loss with subchondral sclerosis, osteophytes and cysts
• •Capsular thickening, synovitis and labral degeneration
• •Weakness of the muscles around the joint, particularly the gluteals

Secondary OA follows a predisposing condition: developmental dysplasia of the hip (DDH), Perthes disease, slipped capital femoral epiphysis (SCFE), femoroacetabular impingement (FAI), avascular necrosis (AVN), inflammatory arthritis, previous infection or fracture.

Risk factors include age, female sex, obesity (a major modifiable factor), genetics, previous injury, structural abnormality, heavy occupational lifting and high-level sport.