Anterior Hip Replacement is a minimally invasive hip surgery to replace the hip joint without cutting through any major muscles surrounding the hip. The surgical procedure involves a small incision in front of the hip, anterior, as opposed to an incision on the side or back of the hip. It is referred to as more muscle sparing surgery because it utilizes a true inter-nervous plane in accessing the hip joint. Unlike the posterior or lateral approach the gluteus maximus or gluteus medius are kept intact.
In order to understand anterior hip replacement and its benefits over traditional hip surgery, it is important to understand the normal anatomy of the hip.
The thigh bone, femur, and the pelvis, acetabulum, join to form the hip joint. The hip joint is a “ball and socket” joint. The “ball” is the head of the femur, or thigh bone, and the “socket” is the cup shaped acetabulum.
The joint surface is covered by a smooth articular surface that allows pain free movement in the joint.
The cartilage cushions the joint and allows the bones to move on each other with smooth movements. This cartilage does not show up on X-ray, therefore you can see a “joint space” between the femoral head and acetabular socket.
The pelvis is a large, flattened, irregularly shaped bone, constricted in the center and expanded above and below. It consists of three parts: the ilium, ischium, and pubis.
The socket, acetabulum, is situated on the outer surface of the bone and joins to the head of the femur to form the hip joint.
The femur is the longest bone in the skeleton. It joins to the pelvis, acetabulum, to form the hip joint.
The upper part is composed of the femoral head, femoral neck, and greater and lesser trochanters.
Arthritis is a general term covering numerous conditions where the joint surface (cartilage) wears out.
The joint surface is covered by a smooth articular surface that allows pain free movement in the joint. This surface can wear out for a number of reasons; often the definite cause is not known.
When the articular cartilage wears out, the bone ends rub on one another and cause pain.
There are numerous conditions that can cause arthritis and often the exact cause is never known. In general, but not always, it affects people as they get older and is called Osteoarthritis.
Other causes include:
The combinations of these factors make the arthritic hip stiff and limit activities due to pain or fatigue.
Hip conditions should be evaluated by an Orthopaedic surgeon for proper diagnosis and treatment.
Your surgeon will perform the following:
Diagnostic Studies may include:
There is no blood test to diagnose osteoarthritis.
Anterior Hip Replacement is a minimally invasive, muscle sparing surgery using an alternative approach to traditional hip replacement surgery. Traditionally, the surgeon makes the hip incision laterally, on the side of the hip, or posteriorly, at the back of the hip. Both approaches involve cutting major muscles to access the hip joint. With the anterior approach, the incision is made in front of the hip enabling the surgeon to access the hip joint without cutting any major muscles. A special operating table is used that facilitates various anatomical positions enabling the surgeon to replace the hip joint anteriorly.
Potential benefits of anterior hip replacement compared to the traditional hip replacement surgery, may include the following:
Anterior Hip Replacement is performed in a hospital operating room under general or regional anesthetic depending on you and your surgeon’s preference. You will be placed supine, on your back, on a special operating table that enables the surgeon to perform your hip replacement anteriorly. Fluoroscopic imaging is used during the surgery to ensure accuracy of component positioning and to minimize leg length inequality.
The surgeon makes one incision to the front of the hip. The surgeon then pushes the major muscles aside to access the hip joint to begin the replacement.
The femur (thigh bone) is separated from the acetabulum (hipbone socket). The acetabulum (socket) is prepared using a special instrument called a reamer. The acetabular component is then inserted into the socket. This is sometimes reinforced with screws or occasionally cemented.
A liner, which is made of plastic is then placed inside the acetabular component. The femur (thigh bone) is then prepared. The femoral head which is arthritic is cut off and the bone prepared using special instruments to exactly fit the new metal femoral component.
The femoral component is then inserted into the femur. This may be press fit relying on bone to grow into it or cemented depending on a number of factors such as bone quality and surgeon’s preference. The real femoral head component is then placed on the femoral stem. This can be made of metal or ceramic. The artificial components are fixed in place.
The surgeon withdraws the instruments and sutures the incision closed. The incision is then covered with a sterile dressing.
For Anterior Hip Replacement patients, however, hip precautions are not necessary. Because the major muscles are not cut, the risk of dislocation is theoretically lessened enabling the patient more freedom of movement after surgery. Some studies have found that the rehabilitation is faster for patients as well in the immediate postoperative period.
Common post-operative guidelines after Anterior Hip Replacement include the following:
Risk factors that can negatively affect adequate healing after hip replacement include: