Hip arthritis is when the cartilage that caps the ends of the bones in the hip joint wears away or is damaged.  The hip is a ball-and-socket joint formed by the head of the femur (thigh bone) and the acetabulum (socket formed by the pelvic bones).  Without healthy, smooth cartilage, the bones begin to grind together.  This causes pain, swelling, and stiffness. Hip arthritis is caused by wear and tear.  Cartilage does not have a very good blood supply and does not heal as well as other tissues.  Over time, it can begin to soften and peel away from the bone.  An injury to the hip can damage the cartilage and speed up the wear and tear.  Lifestyle, obesity, and genetics can play a role as well. Hip pain usually gradually worsens over time.  However, sometimes an injury can aggravate arthritis that was already present.  Typically, hip pain is worse with stairs, getting up from a sitting position, and prolonged walking. Hip arthritis is diagnosed based on a history, physical exam, and x-rays.  Patients usually have a history of gradually increasing pain that is worse with steps, getting up from a chair, or prolonged walking.  Sometimes hip pain begins with an injury because the injury aggravates arthritis that is already present. During the physical exam, the hip may be very tender along the joint line and in the groin. The hip may be stiff and rotating the hip may be painful. In early arthritis, no changes are visible on an x-rays.  As arthritis becomes more advanced, the joint space between the bones narrows and bone spurs form.  X-rays are important when there is an injury in order to rule out fractures (broken bones). Non-surgical treatments for hip arthritis are anti-inflammatory medications like ibuprofen, ice, elevation, and activity modification to include low impact exercise (swimming, water aerobics, etc).  Steroid injections can help to reduce pain and inflammation.  Physical therapy may or may not be beneficial. During hip arthroscopy (hip scope) damaged cartilage can be debrided or removed.  This might provide temporary relief and may be a good option for someone who is not responding to more conservative treatment but is not yet ready for a hip replacement. The definitive treatment for hip arthritis is a hip replacement.  During a hip replacement, the arthritic ends of the bones in the hip joint are removed and replaced with metal implants.  Weightbearing is allowed immediately following surgery, but patients need several weeks of rehabilitation.