THA stands for Total Hip Arthroplasty, commonly known as a total hip replacement. This surgery alleviates chronic hip pain and restores mobility by removing the damaged parts of the natural hip joint and replacing them with a prosthetic implant. It is considered one of the most successful operations in modern medicine for improving a patient’s quality of life.
What Total Hip Arthroplasty Involves
The procedure replaces the hip joint’s ball-and-socket structure with artificial components. The surgeon removes the damaged femoral head (the “ball”) and the worn-out cartilage in the socket, preparing the bone for the prosthetic components.
The prosthetic joint has three main parts: the femoral stem, the femoral head, and the acetabular component. The femoral stem is a metal shaft, often titanium or stainless steel, inserted into the hollow center of the femur (thigh bone). It is secured using bone cement or designed to be “press-fit,” allowing bone to grow onto its porous surface for stability.
A new femoral head, made of polished metal or ceramic, is placed on top of the stem. The damaged socket (acetabulum) is fitted with a metal cup, the acetabular component. A liner, typically durable plastic, metal, or ceramic, is placed inside this cup. This liner acts as the smooth bearing surface for the prosthetic ball, reducing friction and allowing fluid movement.
Common Reasons for Needing a Hip Replacement
The primary indication for total hip arthroplasty is severe, chronic hip pain and stiffness that significantly limits daily activities. The most frequent cause is osteoarthritis, often called “wear-and-tear” arthritis. This condition degrades the cartilage cushioning the hip bones, resulting in painful bone-on-bone friction.
Other forms of arthritis also necessitate replacement, including rheumatoid arthritis, an inflammatory autoimmune disease. Post-traumatic arthritis may develop years after a serious hip injury, fracture, or dislocation, leading to joint breakdown.
Avascular necrosis (AVN), or osteonecrosis, occurs when the blood supply to the femoral head is interrupted. The bone tissue dies, causing the femoral head to collapse and leading to severe arthritis. Severe hip fractures, particularly those in older adults that cannot be repaired, also often require replacement to restore mobility.
The Recovery Process and Long-Term Outlook
Recovery begins immediately after surgery, with patients encouraged to stand and walk short distances with assistance on the same day. The hospital stay usually lasts one to two days, during which medical staff manage pain and monitor for early complications like blood clots. Early mobilization is fundamental, aiding circulation and preventing stiffness.
Physical therapy is central to rehabilitation, starting with gentle exercises to maintain range of motion and progressing to strengthening the muscles around the new joint. In the first few weeks, patients use assistive devices like a walker or crutches, gradually transitioning to walking unassisted. Most individuals resume light daily activities and return to work within six to eight weeks, depending on the job’s physical demands.
Significant improvements in strength and mobility are achieved within the first three months, though full recovery can take six to twelve months. Patients must adhere to specific precautions, such as avoiding extreme hip flexion or rotation, to reduce the risk of prosthetic dislocation. Surgeons also manage the risk of other complications, including infection and nerve damage.
Modern total hip implants are highly successful and durable; 80% to 90% of prostheses last for 20 years or more. While designed for longevity, bearing surfaces can eventually wear, or components may loosen over time. Patients can expect a substantial reduction in pain and a return to most normal activities, though high-impact sports like running are usually advised against to protect the artificial joint.