Arthroplasty is a surgical procedure designed to repair a damaged joint by replacing its worn or diseased components with an artificial implant, known as a prosthesis. This intervention is often referred to as joint replacement surgery, and it aims to restore the joint’s ability to move smoothly and without pain. The procedure provides significant relief from chronic discomfort while simultaneously improving the patient’s functional mobility. By substituting the compromised joint surfaces with durable, man-made materials, arthroplasty offers a pathway for individuals to regain an improved quality of life.
Defining the Purpose of Arthroplasty
Arthroplasty becomes a consideration when joint damage is so extensive that it severely limits a person’s daily activities and causes persistent, debilitating pain. The primary indication for this surgery is advanced degenerative joint disease, most commonly osteoarthritis (OA). Osteoarthritis causes the protective cartilage that cushions the ends of bones to wear down, leading to painful bone-on-bone friction within the joint space.
The procedure is also frequently necessary for individuals suffering from inflammatory conditions such as rheumatoid arthritis (RA). RA is an autoimmune disorder where the body’s immune system attacks the joint lining, causing inflammation and leading to the erosion of cartilage and bone. Arthroplasty is generally recommended only after less invasive, non-surgical treatments—like medication, physical therapy, and injections—have failed to provide lasting relief.
Common Types of Joint Replacement
The most frequently performed arthroplasty procedures target the major weight-bearing joints of the body, specifically the hip and the knee. Total Hip Arthroplasty (THA) involves replacing both the ball (head of the femur) and the socket (part of the pelvis). The damaged bone is removed, and prosthetic components are cemented or press-fit into the pelvis and femur to recreate the joint.
Total Knee Arthroplasty (TKA) involves resurfacing the damaged ends of the thighbone (femur) and shinbone (tibia). Surgeons remove the worn cartilage and a small amount of underlying bone before capping these surfaces with metal components and inserting a plastic spacer to act as a new gliding surface. Arthroplasty is also performed on other joints, including the shoulder, ankle, and elbow. These procedures may involve a total replacement of all surfaces or a partial replacement.
The Surgical Process and Implants
The arthroplasty procedure begins after the administration of anesthesia, which may be general or regional, such as a spinal block. The surgeon makes an incision over the joint to gain access, carefully moving aside muscles and tendons to expose the joint capsule. Specialized instruments are then used to remove the damaged cartilage and bone tissue from the ends of the affected bones.
Once the damaged tissue is removed, the remaining bone surfaces are precisely shaped to accept the prosthetic components. The implants are then secured to the bone, often using surgical cement or designed with a porous coating that encourages the patient’s own bone to grow directly into the implant surface for long-term fixation. Prosthetic components are typically made from a combination of materials chosen for their strength, durability, and biocompatibility.
Metal alloys, such as cobalt-chromium or titanium, are commonly used for the components that attach to the bone. The new bearing surface that allows the joint to glide is often made of highly durable polyethylene, a specialized type of plastic, or ceramic materials. For a hip replacement, the new femoral head may be metal or ceramic, articulating with a polyethylene liner within the metal socket. The surgeon ensures the new joint is stable and moves correctly before closing the incision with sutures or staples.
Recovery and Long-Term Expectations
The recovery phase begins almost immediately, with a strong emphasis on managing pain and restoring mobility. Patients are typically encouraged to sit up and begin walking with assistance, such as a walker or crutches, on the same day as the surgery or the day after. This early movement is important for preventing complications like blood clots and initiating the rehabilitation process.
Physical therapy is a fundamental component of recovery, beginning in the hospital and continuing for several weeks or months afterward. The therapy focuses on strengthening the muscles surrounding the new joint and improving the joint’s range of motion. While significant functional improvements are often noticeable within the first few months, full recovery and maximum strength can take up to a year.
Modern joint replacements are highly successful and designed for durability, offering excellent long-term outcomes. For many patients, the implants are expected to last 15 to 20 years or more, with over 90% of knee replacements still functioning well after 10 years. Patients can typically return to low-impact activities like walking, swimming, and golfing. High-impact activities such as running or contact sports are generally discouraged to protect the lifespan of the implant. Regular follow-up appointments with the surgeon are necessary to monitor the implant and ensure its continued function.