Total knee arthroplasty, or total knee replacement surgery, is a common procedure used to treat severe knee joint damage. CPT code 27447 is the medical billing code for this comprehensive operation. This code represents the complete surgical process of replacing the knee joint with artificial components (prosthesis). The procedure involves substituting the damaged ends of the thigh bone (femur) and shin bone (tibia) with metal implants and inserting a plastic spacer between them. CPT 27447 covers this arthroplasty, regardless of whether the undersurface of the kneecap (patella) is resurfaced.
Conditions Requiring Knee Replacement Surgery
The primary reason a physician recommends total knee replacement surgery is advanced arthritis that has severely damaged the joint surfaces. Osteoarthritis, often called “wear-and-tear” arthritis, is the most frequent cause, affecting individuals over 50. In this condition, the protective cartilage cushioning the bones softens and wears away, leading to painful bone-on-bone friction and the development of bone spurs.
Other significant causes include rheumatoid arthritis, an autoimmune disorder where the joint lining becomes inflamed, eventually destroying cartilage and bone. Post-traumatic arthritis, which develops years after a serious knee injury or fracture, is another common indicator for surgery. Regardless of the type, the joint damage causes severe pain and stiffness that significantly limits everyday activities like walking and climbing stairs.
Total knee arthroplasty is reserved for individuals whose pain is constant, affects their sleep, and has not improved with non-surgical treatments. These conservative options include anti-inflammatory medications, corticosteroid or lubricating injections, and physical therapy. When these treatments fail to provide substantial relief, and imaging confirms severe joint deterioration, surgical intervention becomes the next step.
Detailed Steps of the Operation
The procedure is performed under general or spinal anesthesia and takes one to two hours. The orthopedic surgeon begins by making a precise incision, often along the center of the front of the knee, to access the damaged joint. The kneecap is temporarily moved aside to fully expose the ends of the femur and tibia.
Specialized instruments remove the damaged cartilage and a minimal amount of underlying bone from the femur and tibia. This preparation shapes the bone surfaces precisely to ensure a proper fit for the artificial components. The goal is to correct any existing deformity and restore the natural mechanical alignment of the leg.
The metal femoral component, curved to mimic the thigh bone, is secured to the prepared femur. Next, a flat metal tray is fixed to the tibia. A smooth, medical-grade plastic insert (polyethylene) is snapped into the tibial tray to function as the new cartilage surface.
If required, the patella is resurfaced by removing damaged cartilage and attaching a small plastic component (patellar button). The surgeon checks the joint’s movement and ligament tension to ensure stability and range of motion. Once the components are correctly aligned and secured, the incision is closed with sutures or staples.
Recovery and Rehabilitation Timeline
Recovery begins immediately, with the patient spending one to three days in the hospital for monitoring and initial pain management. Controlling post-operative pain and swelling through medication and icing is a high priority to facilitate early movement. Patients are encouraged to begin gentle ankle pump exercises and knee bends within hours of the surgery to improve circulation and prevent stiffness.
Early mobilization is key to successful recovery, and physical therapy starts on the same day or the day after surgery. Aided by a walker or crutches, most patients are able to stand and take a few steps shortly after the procedure. The focus during the first few weeks is on regaining the ability to fully straighten the knee and increase the bending range of motion.
The first six to twelve weeks involve intensive physical therapy, the most active phase of rehabilitation. During this time, the patient works to transition from using walking aids to walking unassisted and to build strength in the muscles surrounding the new joint. Patients can resume driving after four to six weeks, provided they have regained control and received surgeon approval.
While significant improvement occurs in the first few months, a full return to all regular activities, including demanding physical tasks, takes six months to a year. The long-term success of the total knee replacement relies heavily on the patient’s dedication to the prescribed exercise program, which strengthens the joint and maximizes the longevity of the implant.