Evolution of Technology

Total Knee Replacement

Total knee replacement surgeries have been performed since the late 1800’s and fortunately technology has continued to advance throughout the history of the procedure. Currently the most common material used for components are various metal alloys to include titanium, cobalt-chrome, and stainless steel as well as high grade plastics known as polymers.

Most systems consist of three parts, the femoral component which caps the endo of the femur, the tibial component which caps the top of the tibia, and the poly (short for polymer component) which rests between the tibial and femoral component and acts as the new cartilage or bearing surface. Many different companies produce components used in total knee replacement and all of the currently used implants have been extensively studied and approved to be safe for use by the Food and Drug Administration.

Regardless of the implant chosen by the surgeon, due to the improvements in technology and material properties throughout the history of total joint procedures, current implants are the best that we have ever had and demonstrate improved wear rates, longer success periods, higher success rates, more anatomic designs, and decreased need for revision surgery due to wear.

Evolution of Procedure

Joint Replacement Surgery

Joint replacement surgery is one of the most commonly performed procedures in all of orthopaedics and has been shown to be one of the most successful with greater than 90% of patient experiencing satisfactory results. The key to the surgery is to remove the native joint surfaces at the distal femur, proximal tibia, and patella and to replace these surfaces with metal and plastic components which act as the new weightbearing surfaces of the joint. Typically, the procedure is performed over the course of one to two hours and is performed under either general anesthesia or a spinal anesthetic (such as an epidural) with lighter sedation. The surgery is performed through a single incision at the front of the knee, although there are some surgeons who prefer hybrid or minimally invasive approaches, none of these have been shown to be superior to standard approach. Patients are most commonly allowed to walk on their new knee the same day as surgery and are typically discharged from the hospital same day or one day later.

Evolution of Diagnosis

Tri-compartmental (complete) Osteoarthritis of the Knee

Osteoarthritis of the knee is a degenerative condition of the joint which causes progressive loss of articular or joint lining cartilage. The disease process occurs over many years and is typically a result of natural aging and degeneration over time although it can be accelerated by things such as a history of traumatic injury or ligamentous instability (ie. Chronic ACL tear). Knee osteoarthritis is very prevalent, occurring in a large percentage of patients over the age of 60 years old.

Risk factors include previous injury to the knee as stated above as well as large body mass, obesity, abnormal cholesterol and triglycerides, high blood pressure and diabetes. The condition affects women more commonly then men. There are multiple treatment options to attempt to improve symptoms of knee pain and loss of function associated with knee arthritis. Theses include physical therapy, weight-loss, activity modification and injections into the joint.

Ultimately, these options simply treat the symptoms of the disease and do not cure the underlying cause, which is loss of knee cartilage, and eventually if symptoms progress surgery is needed. To date the only indicated surgery for osteoarthritis affecting the entire knee joint is total knee replacement.