Useful Facts on Hip Replacement Surgery

Over the last three centuries, treatment of hip arthritis has evolved from rudimentary surgery to modern total hip arthroplasty (THA), which is considered one of the most successful surgical interventions ever developed.

Anthony White (1782-1849) of the Westminster Hospital in London is credited with the first excision arthroplasty in 1821. This procedure ameliorated pain and preserved joint movement but joint instability was a problem resulting from the surgery.

John Rhea Barton (1794-1871) in Philadelphia is credited with performing the first osteotomy on an ankylosed hip in 1826.

Léopold Ollier’s (1830-1900) work at the Hôtel-Dieu hospital in Lyon, France. In 1885, he described the interposition of adipose tissue in uninfected joints.

Berliner Professor Themistocles Glück (1853-1942) led the way in the development of hip implant fixation. In 1891, Glück produced an ivory ball and socket joint that he fixed to bone with nickel-plated screws.

Sir John Charnley (1911-1982) work at Wrightington Hospital. In November 1962 the Charnley hip replacement became practical reality and has become the gold standard for this form of treatment. Clinical and radiographic success of this procedure is now approaching 40 years of follow-up. Charnley's design consisted of two parts a metal (originally stainless steel)) a femoral component and a teflon acetabular component; both were fixed to the bone using bone cement (acrylic).

The current hip joint replacement prosthesis is composed of four major components:

1. A metal socket that replaces the acetabulum;
2. A liner with highly polished inner part representing the articular surface. (It is usually plastic, but other materials are also used such as ceramic or metal. The liner allows the hip to move smoothly.)
3. A metal stem that is inserted in the femoral canal; and
4. A metal or ceramic ball, which articulate with the liner.

There are two types of implants:

1. Cemented hip replacement system, which was first described by Sir Charnley and is still currently used with some modifications and
2. A biological non-cemented system, which depends on the body ingrowth or ongrowth on the metal surface.

The most common indication for THA is degenerative arthritis (osteoarthritis) of the hip joint. This type of arthritis is generally seen with aging, congenital abnormality of the hip joint, or prior trauma to the hip joint. Other conditions leading to total hip replacement include bony fractures of the femoral neck at the hip joint, rheumatoid arthritis, osteonecrosis (death of the femoral head) and developmental dysplasia of the hip.

There are no absolute contra-indications however, few relative contra-indications can be summarised including:

• skeletally immature patient,
• active sepsis or active infection in the joint.

Different approaches have been used to perform hip joint arthroplasty. To date there is no compelling evidence in literature for any particular approach, but consensus of professional opinion favours either the posterior approach or the modified anterio-lateral approach.

Over the last few years there has been a significant amount of debate over the minimal invasive surgery (MIS). The results of surgeries using this technique has not proven to be better than the standard approaches, in fact some studies show an inferior outcome of MIS compared to standard approach. The use of computer navigation in hip arthroplasty is another controversial subject since it hasn’t shown any significant evidence of a better outcome than using standard approaches.

The common approaches to the hip joint for Hip Replacement are:

• The posterior approach accesses the joint through the back, taking the short external rotators off the femur. This approach gives excellent access to the acetabulum and preserves the hip abductors so the patient has less chance of a limp after surgery. Critics cite a higher dislocation rate, although repair of the capsule and the short external rotators negates this risk.
• The lateral approach is also commonly used for hip replacement. This approach requires elevation of the hip abductors (gluteus medius and minimus muscles) in order to access the joint. The abductors may be lifted up by osteotomy of the greater trochanter and reapplying it afterwards using wires. This approach has lesser chance of dislocation; but the patients are more likely to develop a limp after surgery, which might be permanent.
• The anterolateral approach develops the interval between the tensor fasciae latae and the gluteus medius. Recently the anterior approach utilises an interval between the Sartorius muscle and tensor fascia latae has become more popular especially with the use of a special table that allows hip extension. The advantage of this approach is a small incision and no cutting to any muscle; but it is more technically demanding and requires proper patient selection since it is very difficult to use this approach on obese or muscular patients.

I believe that the best approach is the one that the surgeon is more comfortable with as long as optimal visualisation of the joint anatomy is obtained using as minimal soft tissue dissection as possible with efficient time utilisation.

For almost 40 years, hip replacement surgery has been widely used and successful. It has brought about immediate substantial improvement to patients by reducing pain and improving the function and over-all health-related quality of life. Of the 600,000 total hip replacements performed each year throughout the world, approximately 90% will last 10 years or more. Revision surgery may be able to keep people on their feet for even longer. Over the past 20 years, complications have significantly declined due to the use of antibiotics and anticoagulants during and after surgery. Mechanical loosening has decreased due to improvements in prosthesis design and materials, prosthesis implantation, and other aspects of surgical technique.

Although the benefits of successful hip replacement surgery are great, you as the patient have a duty to care for your new artificial hip by avoiding movements that will stress or damage its components. It is particularly important to avoid prohibited positions of the leg and to treat infections that cannot be avoided. If this care is taken, your efforts should be rewarded for years to come.