Total hip replacement options
By Herb Boté, M.D.
Total hip replacement implies a replacement of damaged ball and socket of the hip joint, which is a treatment for a number of diseases, the most common being osteoarthritis. The total hip replacement procedure was introduced as a reasonable treatment in the late 1950’s. It originally consisted of cementing a metallic ball joint connected to a metal shaft along with a cemented plastic socket joint. Some of these replacements are still being performed.
Currently, the most popular procedure is to insert a metallic ball and shaft along with a combination metal and plastic socket. The metal socket and the metal ball and shaft are pressed against the bone without the use of cement. With this system, bone will grow into the metal, thereby biologically fixing the implants to the patient’s body. This is called biological fixation, which is the goal. Wear and tear that occurs when two materials are in contact and actively moving with each is the enemy of any system. There are procedures that try to use other materials to reduce this problem. Alumina or ceramic ball joints have been used with success. The plastic we currently use is a high grade polyethylene that is engineered to minimize this problem. Ceramic is a very hard substance with virtually no wear possibilities, but it has a risk of cracking microscopically due to its inherent brittleness. There is also a new technique being studied in which a metal ball and a metal socket are applied together. The benefit is that larger components could be used. This would entail a higher degree of stability meaning that there would be a significantly lower risk for dislocation. As far as surgical technique is concerned, the publicly popular mini-incision or two-incision technique has not gained acceptance in the general orthopedic community, because of the steep learning curve and high rates of complications. Further studies are being performed. There is also a movement mainly in the European community in which only a portion of the ball joint is removed and the rest of the shaft of the femur is preserved. There are too few studies to support this technique at this writing. In addition, there is also a steep learning curve and complications do arise. In summary, total hip replacement has been a very successful and rewarding treatment for patients suffering from painful arthritis of the hip. There are ongoing studies to increase the longevity of the implants and minimize the dissection needed to perform the procedure.
Dr. Herbert Boté is a board certified orthopedist who is part of Berkshire Orthopaedic Associates in Pittsfield.
