Anterior Vs. Posterior Hip Replacement
The anterior approach to doing a total hip replacement has been gaining popularity in the US over the last ten years. It is a technique that patients seek out for several reasons. They generally feel like it is a less painful technique, allows earlier rehab and has fewer restrictions than the traditional posterior approach. There are a lot of anecdotal experiences related online by patients that support this opinion.
What has been proven in terms of scientific studies is that although the initial recovery is faster with the anterior approach, at three months there is no difference between well placed total hips done with the anterior approach versus the posterior approach. The key phrase here is "well placed.” I used the posterior approach for all hip replacements I performed from 1983 until late in 2013. From that point on, I have used the anterior approach to hip replacement almost exclusively for primary hip replacement and have even used it on selective revision surgery. My frustration with the posterior approach was achieving well placed components on a consistent basis, in particular the acetabular component. (The acetabular is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.) Proper placement of total hip components is one of the key factors in achieving excellent long term results with a total hip replacement. In my hands, I feel like proper placement of the components is something that is much more consistent with the anterior approach.
The goals of a total hip replacement done by any approach are:
1. A painless joint that functions well.
2. Eliminate complications- Some of the major complications from total hip replacement are: infection, dislocation of the components, deep venous thrombosis (blood clot), pulmonary embolism (A condition in which one or more arteries in the lungs become blocked by a blood clot), loosening of the components, intra-operative fractures, leg length inequality and anesthetic complications, including death.
3. Decrease the blood transfusion rate.
4. Decrease the length of hospitalization.
So how does the surgical approach impact all of these goals and complications? Is there one surgical approach that is always superior to any other?
The answer is not so black and white, but more of a shade of gray.
Total hip replacement is carried out via the posterior approach about 2/3 of the time in this country. The anterior approach is done about 25% of the time and other approaches account for the remainder. The posterior approach is what has been taught in most orthopaedic training programs across the country, because it is versatile and most problems with the hip joint can be addressed with the posterior approach. This includes femoral neck hip fractures and hip replacement for arthritic conditions. The anterior approach is not a new approach and has been around since the early 20th century. Its' widespread use has not occurred since it literally is 180 degrees from the posterior approach in terms of how the surgeon views the hip anatomy. Quite frankly it is an approach that can be daunting until the surgeon becomes use to it and learns the strengths and weaknesses that it presents. So why would someone who was very comfortable with the posterior approach switch to the anterior approach? In a nutshell because I feel like my patients have better results and fewer complications. I have no scientific proof of this other than what I have seen on a daily basis with my own patients.
I feel like my dislocation rate is significantly lower, my placement of components is where I want them 95% of the time, my transfusion rate is lower, my incidence of deep venous thrombosis and pulmonary embolism is lower, my length of stay in the hospital is lower, my incidence of leg length inequality is almost non-existent, narcotic usage is decreased, my blood loss is decreased and most importantly my patients are much happier.
Anterior hip replacement is done with the patient lying on their back on a special table that allows precise positioning of the affected leg. The use of a fluoroscopy unit allows real-time imaging of the hip as the procedure is done. This allows precise placement of components that are correctly sized. It also allows for precise leg length equalization, which is a major complaint patients have when their leg lengths are not equal. Since the lower extremity doesn't put the femoral vein in a twisted position for a prolonged period of time, it appears the incidence of deep venous thrombosis is decreased in patients who have the anterior approach. The anterior approach goes between muscle planes instead of cutting through muscle like in the posterior approach. This is less painful and less blood loss occurs.
The bottom line is that the anterior approach, in my hands, has given me and my patients a better result both short term and long term. It is a less invasive, less painful approach that is quite noticeable in the short term in regards to pain, length of stay in the hospital and walking ability in terms of distance walked and use of assistive aids such as a walker or a cane. It allows precise placement of components, which is most important in how patients do in the long term. As far as I'm concerned it is the preferred approach for doing primary hips. It is also becoming my preferred approach for revision hip replacement. Nationally, anterior total hip replacement continues to gain popularity among patients and surgeons. It is my opinion that the anterior approach will continue to gain popularity based on its' merits, not the fact that it is a fad.