It is estimated that as many as 40 million Americans or 1 in 7 people have some form of arthritic disease.
It has been reported that arthritis is the number one cause of disability in America, limiting the everyday activities
for approximately seven million individuals. The efforts of medical researchers have greatly improved the understanding
of arthritis. Their discoveries have resulted in more effective treatments and a higher quality of life for people
living with the disease.
When conservative methods of treatment to provide adequate relief for patients suffering from disabling hip disease,
total hip replacement is considered. Today, more than 180,000 people in the United states annually undergo hip
replacement surgery with the intent to diminish pain and stiffness and restore mobility. A total hip replacement
operation involves removing the diseased portions of the thigh bone ( femur ) and (acetabulum ), and replacing them
with medical grade plastic and metal components that replicate the ball and socket joint.
Traditionally, after preparing the bones for the components, a filler or grout similar to dental cement has been
used to hold the implants in place. The cement is injected into the bone and a metal stem with a ball head is
inserted into the cement. It was seen however that through the years, pressure on the new joint often caused the
cement to crack and the implants to loosen over tirme. The younger the patient or the more vigorous the person's
activities, the more quickly the artificial hip was likely to need replacement. Another standard method for hip
implantation involves "press fitting" a porous coated or beaded implant into the bone. The porous surface implants
rely on bone ingrowth into the pores for stability. However, it has been seen in some patients that ingrowth does
not occur consistently with these porous devices.
Today there are alternative technologies that enable the surgeon to implant a hip prosthesis without cement.
Hydroxylapatite coated hip implants is one such technology. Hydroxylapatite is a material that closely resembles
the properties of natural bone. It is a mineral that naturally occurs in the human body and the predominant
component of your bone and tooth enamel. It can be reproduced synthetically and has been under clinical evaluation
for some time. This compound is applied directly to the upper portion of the hip implant. The implant is then
securely pressed into the femur, no cement is used. Hydroxylapatite has demonstrated to be non toxic, non allergenic,
biocompatible and non- inflammatory.
In 1986, Osteonics Corporation of Allendale NJ, a pioneer in using Hydroxylapatite technology on orthopaedic implants,
first began clinical use with an Hydroxylapatite coated hip implant in Europe. In 1987 they began an investigational
study in the United states. A ten year clinical review of this technology from these studies reveals overall positive
results for the study participants who suffered from arthritis. These patients ranged in age from 16 to 81 at the time
of operation. Of the patients in the study which have reached a minimum seven years followup, over 95 percent report
that they have no or slight pain. Thus, Hydroxylapatite coated components provide a viable alternative to both cemented
and porous hips in active patients and allow many patients the opportunity to resume normal, non impact activities.
Current Concepts Review: Total Hip Arthroplasty with Hydroxyapatite-Coated Prostheses.