Anterior Hip Replacement has really become, in my mind, the standard for primary (or first time) hip replacement surgery.
That wasn’t always the case, however. Not too many years ago the posterolateral and anterolateral/lateral approaches to the hip were the most commonly used approaches. They offer excellent exposure to the hip joint and allow surgeons to get all the instruments they could ever want into the area to perform the hip replacement. However, using those approaches comes at a cost: in order to get into the hip, one or several tendons need to be detached or split from the bone and the hip dislocated out of its socket.
Over the years of doing these approaches, the outcomes data showed the results of those costs. With the anterolateral or lateral approaches, because of the damage to a group of muscles and tendons called the abductors, patients ended up with a specific type of limp called the Trendelenburg gait. Sometimes that was painful, and sometimes it wasn’t, but it certainly changed the way patients walked. With the posterolateral group, the abductors were preserved better, but different tendons called the external rotators were released from the bone. These tendons are important to prevent dislocation of the hip replacements, and therefore the posterolateral approaches (historically) had higher dislocation rates.
Eventually, surgeons started to wonder if there was a better way.
The anterior approach to the hip was described as early as 1881. For years after that, it was used in select surgeries around the hip, but not for hip replacements until 1945. Still, it was quite rarely described until the 1980’s when several surgeons started to describe their results and techniques.
In this early period of anterior hip replacement, there were still complications associated with the surgery, just like the other approaches. More commonly than in the other approaches, there were fractures of the femur bone during or after the surgery, and in certain patients incision complications (because the wound is close to the groin area). But the data showed a significant change in the amount of patients with limps or dislocations.
From there, surgeons and engineers started to develop specific tools and implants that were more friendly for the anterior approach. As that happened, the incidence of fractures started to decrease, and outcomes started to improve. With more study about the incision and wound healing, surgeons went on to develop what is called the “bikini incision” which has a physiologic advantage to healing compared to the traditional incision and has been shown to have a decreased infection risk.
At first there was pushback to the anterior approach. Many surgeons who used the “traditional approaches” said that it was all just a “marketing campaign” or that the learning curve was too high to justify a change. But over time the results of the surgery continued to show some advantages to the anterior approach compared to the other approaches, and eventually more and more surgeons employed the approach and taught it to learning surgeons.
This eventually changed the hip replacement completely.
As more and more patients started to hear about the anterior approach and ask for it, it created market forces that led more surgeons to learn and continually refine the anterior approach.
However, it also forced surgeons using the other approaches to explore ways to improve their own outcomes. They either had to do that, or go and learn the anterior approach, because they couldn’t risk being the surgeon that had inferior results because of their approach.
Posterolateral surgeons found ways to release fewer tendons, and to better repair the ones they do release. They started using better implants and employing technology to ensure all the parts of the replacement were put in the correct position. This decreased the dislocation rates of this approach.
Anterolateral surgeons found ways to cut either less of the abductors or avoid cutting into them at all, utilizing a similar muscle interval to the anterior approach and accomplishing the same goal. This improved the incidence of the limp after those surgeries.
The truthful answer to that question is “it depends.” What the literature shows us is that if a surgeon does the approach that they are best at and most comfortable with, using modern day technology and implants and following evidence based protocols, most hip replacements actually do really well. The outcomes are pretty similar no matter what approach is done. There still remains a small amount of risk for each approach (slightly higher dislocation risk for posterior approaches, slightly higher risk for fracture in anterior approaches) but the difference is rarely “statistically significant,” depending on what study you read. All in all, hip replacement is a great surgery and with rare exception, patients do well after them.
Personally, I am most comfortable with the anterior approach. With the implants that I use and the methods during surgery I employ, I feel most comfortable with the approach and feel confident in the results for my patients. I feel there are some small advantages to the anterior approach regarding implant positioning, dislocation, leg length correction and many other detailed and important facets to the operation, at least in my experience and training. Fortunately, I have been lucky enough that my complication rate with the anterior approach is very low, and as is usually the case for hip replacement, the patients recover well, quickly, and are happy with their outcomes nearly every time.
As I routinely discuss with my patients, not every patient has the same outcome from a surgery, even if the surgery is done exactly right and the same way from patient to patient. It is just a factor of each individual being different and having different genetic predispositions for different outcomes. There are never any guarantees in surgery or outcomes, and this is no different.