The most common disorder to affect the hips is osteoarthritis (OA), which erodes cartilage and exposes the bone beneath. Advanced cases of hip OA require surgery.

Other diseases that can badly damage the hip joint include:

• Inflammatory arthritis, such as rheumatoid arthritis, which actively corrodes cartilage and bone, and
• osteonecrosis, where the femoral head and neck die as a result of disrupted blood supply caused by a fracture or long-term steroid use or long-term alcohol abuse.

Signs and Symptoms
The medical term, arthritis, means “inflamed joint” and is defined by five classic symptoms – heat, redness, swelling, stiffness and pain lasting more than six weeks. You may not be able to detect all of these symptoms in the hip since it is overlaid with thick layers of muscle and fat. Apart from a dull ache and stiffness, especially in the morning, other common early symptoms are sharp recurring pains in the thigh, groin, buttocks or tail bone.

Causes
Cartilage is a unique tissue type in that it has no blood or nerve supply, which makes sense given that cartilage’s main function is to absorb shocks and allow one surface to rub against another friction-free and painlessly. However, it means that cartilage is very slow to renew and heal the many micro-injuries that occur with daily activities. As we age, that renewal rate slows down even more, and the rate of injury outpaces the rate of repair. Key cartilage cells, called chondrocytes, die and aren’t replaced. Eventually the cartilage dries and starts to crumble along different fault lines and fractures on its surface.

Diagnosis
Your doctor will gently put your hip through its range of motion to gauge how severely the joint is restricted. A final diagnosis is usually confirmed by x-ray.