The Hip

Hip replacement surgery - also known as Total Hip Arthroplasty - has been one of the most important surgical advances of this century. Today, more than 172,000 total hip replacements are performed each year in the United States. 

A Healthy Hip

The hip joint is the second largest joint of our bodies.  When people think of the hip, they naturally think of the buttock area. In anatomic terms, the hip joint is actually the ball-and-socket joint where the thigh bone (femur) meets and articulates with the cup-shaped socket formed by the pelvic bones (the acetabulum).

The top of the femur is shaped like a ball and is called the femoral head. A healthy femur is covered with cartilage and moves within the hip socket, which is also lined with cartilage. Together the two articular cartilage surfaces are about a quarter of an inch thick in a healthy hip joint. Articular cartilage accounts for the clear space normally seen between the two bones on an x-ray of the hip. This cartilage functions as both a shock absorber and a low-friction surface that enables smooth gliding of the hip joint and pain-free, unrestricted motion.

An Arthritic Hip

The various types of arthritis damage the smooth gliding surfaces of the hip joint, ultimately resulting in painful bone-on-bone surface contact. Essentially, arthritis is the wearing down of joint cartilage. While cartilage itself does not have nerve endings, the bone of the femoral head and the acetabulum do, and these nerves get stimulated (painful) when the bone surfaces rub together. As the the arthritis progresses and the cartilage wears out, this hip pain becomes progressively worse.

In addition to the pain caused by cartilage wear, when the cartilage has worn to the point that bone surfaces wear on each other, the body begins attempting to heal the damage by creating new bone - in the form of bone spurs. Bone spurs in the hip joint can cause additional pain, with grating or popping that can be felt and sometimes even heard.

Non-Surgical Treatments for Hip Arthritis

In the early stages of arthritis, there are non-surgical treatments that can help manage hip discomfort. These include:

• Limiting activities that aggravate the hip (but without becoming sedentary)

• Using a cane to decrease the force applied to the joint

• Gentle exercises to maintain muscle tone and range of motion

• Losing weight if obesity is a contributing factor

• Cortisone injections into the joint (a limited number times)

• Non-Steroidal Anti-Inflammatory Drugs to decrease inflammation

These non-surgical treatments can buy time before a hip replacement surgery is necessary. They can make the arthritic hip less painful, and may slow the arthritic process. However, they just treat the symptoms and not the cause.

Hip Replacement Surgery

Hip replacement surgery is a highly effective treatment for severe arthritis of the hip. Hip replacement surgery in reality a joint resurfacing procedure. It eliminates pain and restores mobility by removing the diseased bone and replacing worn out cartilage with a prosthesis of man-made artificial materials.

Traditional hip replacement surgery involves an incision of 10-12 inches over the side of the hip and buttock. The underlying muscles are split or cut to enable the surgeon to get to the hip joint and resurface or replace it.  The comparative illustration at right shows the incision for a traditional hip replacement in red.

Minimally Invasive hip replacement surgery involves a much smaller incision of 2 ½ -5 inches, with less splitting of the underlying muscles.  Dr. Woods utilizes a mini-posterolateral incision to perform the MIS total hip replacement.  This is shown in the illustration at right in blue. 

Specialized instruments are used to work through the mini-incision to remove the arthritic surfaces and prepare them for the new surfaces. The short muscles and ligaments that are taken off the top of the thigh bone (femoral neck) are reattached carefully to the bone at the end of the procedure to restore stability and function.

In addition to careful attention to the surgical technique, Dr. Woods also uses the latest in pre-operative, intra-operative and post-operative pain management.  As a result, his patients typically describe their pain both while in the hospital as well as after returning home as ‘more like an ache.’

Patients are allowed to immediately bear weight fully on their replaced hip, frequently on the day of surgery.  Although all patients are different with regard to their pre-operative health status it is not unusual to see patients walking one to two miles a day by their six week post-op check.