Total Hip Replacements: Posterior versus Anterior Approach
- Published on Wednesday, 04 November 2015 16:43
- Written by Kateri Kane
Total hip replacements or arthroplasties (THA) are one of the most commonly performed joint replacement surgeries. With wear and tear, broken bones, and various problems with blood supply that can occur at the hip, there will always be a need for some type of procedure like this. The components involved and surgical approach for the replacement may vary, though, based on an individual’s age, past history, and desired activity level.
There is more than one way to perform a THA, but the overarching mechanics are the same. Just like the shoulder, the hip joint is a ball-and-socket joint; thus, the prosthetic (artificial) portion of the hip joint consists of two parts: a cup-like component that is attached to the acetabulum (a portion of the pelvic bone) to make a socket, and a shaft with a round top that attaches to the femur (long bone of the leg) to make up the ball. The damaged parts of the hip bone are removed and replaced with the prosthetic components. There are several different types of materials that can be used for the hip prosthetic. These material combinations can include metal-on-polyethylene, metal-on-metal, and ceramic-on-ceramic. Each material combination has both pros and cons so it is important to discuss the best type of replacement for your intended level of activity. The same is true for the attachment of the prosthetic. There is an option of cementing the replacement parts to the bone or doing what is called a press fit which allows bone to grow into the prosthetic to hold it securely in place. Determining which technique to use will depend on several factors including bone quality and strength.
In addition to the different types of material and attachment techniques that can be used for the hip joint prosthetic, the type of surgical approach used is also important to understand. The most popular approach is known as the posterior approach. During this surgery a curved incision is made along the posterior (back) hip which wraps down and to the side of the hip. The incision used is approximately 10 to 12 inches long. Muscles and soft tissue that typically keep the hip stable are then cut, including the fascia lata, gluteus maximus, and several external rotator muscles of the hip. The hip is dislocated, the arthritic surfaces of the bone are removed, the prosthetic pieces are attached, the hip is relocated in the socket, muscle and soft tissue that were previously cut are reattached, and the incision is closed.
The anterior approach is a different method of hip replacement which is not used as frequently as the posterior approach. During this procedure an incision is made on the anterior (front) side of the hip instead of the posterior side. The surgeon works between the muscles without detaching them from the bone when they replace the arthritic surfaces, thus less muscle damage occurs. Along with the increased difficulty in performing this approach for a THA, the anterior approach requires a special table to be used in order to perform the procedure. This may account for some of why the procedure is not used as often as the posterior approach.
So what are the pros and cons for having a posterior or anterior hip replacement? Posterior hip replacements:
- Provide the best view of the hip
- Less likely to cause nerve damage
- Must maintain strict hip precautions to prevent dislocation
- Greater risk of dislocation (due to stabilization muscles being cut and then reattached)
- Cutting of major muscles which require reattachment
Anterior hip replacement
- Less damage to muscles
- Less post-operative pain (due to less muscle damage)
- Faster recovery than traditional posterior approach
- Decreased risk of dislocation (due to muscles that stabilize hip not being cut)
- Better range of motion (due to lack of strict hip precautions limiting motion)
- Shorter hospital stay (but can vary based on patient and frequency of therapy in the hospital)
- Obese or very muscular patient’s may not be good candidates
- More challenging and technical surgery than posterior approach
- Less visibility
- Have to work between muscles without cutting or damaging nerves
- Potential risk for nerve damage
- Wound healing issues with patients with a larger amount of abdominal fat
Do your research in order to help determine which method and surgeon are the best for you. As the THA procedure has been refined over the years, its longevity has improved thus allowing it to be performed at a much younger age than in previous decades. There is over an 80% chance for a hip replacement lasting 20 years. Various factors can increase the chances of failure, however, including an individual’s weight being over 165 lbs as well as level of activity. Performing strengthening exercises is good for stabilizing the hip, but excessive high impact exercises can cause too much force and can increase the likelihood of replacement failure. Despite the recent trends, rehab is very important in order to regain your full potential and recovery. We have treated several patients who were told that they did not need outpatient physical therapy and ended up with other complications afterward. For more information on the importance of rehabilitation following a total joint replacement surgery, check out our past blog on the topic here.