Pursuit of the Perfect Total Hip Replacement: Does Approach Matter?

Darren Herzog, M.D.

Side by side at the scrub sink, surrounded by sterile cold stainless steel, diligently scouring our hands with foamy pink soap and an overly aggressive scrub brush, my fellowship mentor would break the scrubbing silence by posing the question to me. “Do you think we will perform the perfect total hip today?”

I, wide-eyed and impressionable, not to mention nauseatingly eager, would either emphatically agree or respond, “I think we will get as close as possible.” And as I grew more comfortable in my role as the arthroplasty fellow at UCSF that year, I began exploring the concept of a perfect total hip with my own questions. Could the perfect total hip mean different things for the surgeons performing it compared to what it would mean for the patient? What factors play a role in increasing the chance of achieving the perfect total hip replacement surgery?

What role does the approach play? Throughout my career, I have explored how the surgical approach can bring me closer to a perfect total hip replacement.

The most commonly performed approach to accessing the hip joint is known as a posterior approach. This approach requires cutting some of the muscle and tendons off the bone “posteriorly”, or from the back of the hip. This is the work-horse approach for total hip replacement, at least in the United States. It is easily taught, often quicker than other approaches, and highly reproducible. One risk of using this surgical approach is a very small increased rate of prosthetic dislocation, where the new mechanical hip can pop out of its plastic socket. This can be quite painful, distressing and commonly requires a trip to the emergency room to be reduced or possibly surgically revised should it recur. To diminish this risk, the muscle and tendons (known as the short external rotators) must be robustly and carefully reattached.

I began my career following fellowship primarily performing posterior approach hip replacements and still will utilize this approach for 5-10% of cases. This approach is useful in revisions and even more complex cases. But I moved away from this approach primarily to further pursue our goal of the perfect hip replacement. I felt and still do, there must be a better way.

By contrast, a Direct lateral or a modified Hardinge approach both require the partial or complete detachment of a portion of the abductor muscle from the hip, specifically a portion of gluteus medius. The abductor tendon is reattached but post-operative muscle weakness can leave a patient with a waddling limp. There is the benefit of a decreased dislocation rate with these approaches, but at what cost? It is rare to see any of the laterally-based approaches used today and, in my opinion, for good reason. Routinely detaching the most important stabilizing and strengthening muscles of the hip joint from the femur is not only unnecessary but, dare I say, barbaric. I performed a few hip replacements in my first year of practice using the Hardinge approach. But the trauma illustrated here made it clear to me that these were not going to get me any closer to my goal of achieving perfection. I continued my search.

I did not want to routinely subject my patients to the amount of muscle disruption of posterior and lateral approaches, and almost ten years ago I taught myself the Direct Anterior Approach (DAA) for total hip arthroplasty. Cadaver labs, surgical demonstrations and observing master surgeons helped me to overcome the learning curve. As a fellowship trained total joint surgeon who spent the majority of their clinical time (and often personal time) pondering hip and knee arthroplasty, it was a relatively easy transition and an amenable fit.

The DAA uses an interval between muscles on the front of the hip, where I can access the hip joint by spreading the tissue. There is no cutting or traumatic detachment of muscle or tendon from bone. The DAA further appeased my desire for intra-operative control and feedback regarding where the implants are placed and positioned. By positioning patients flat on their back during surgery, as opposed to on their side for other approaches, we are able to more accurately reconstruct their hip anatomy using implants. Supine positioning also allows much easier use of intra-operative fluoroscopy in real time which shows easy and understandable imaging of the hip, the implants and their position during surgery, all factors which can help minimize risk of dislocation, improve function and increase longevity of the implants. Compared to other approaches, there is less pain after surgery, a quicker recovery, lower dislocation rate and no need for cumbersome, limiting hip precautions. For me, this approach was the way. It has become the means for me to get as close as possible to performing the perfect total hip replacement and to give my patients the best outcome I can provide.

The most ideal approach for hip replacement surgery continues to be a hotly debated topic amongst hip surgeons and no clear consensus exists. For me, the most ideal and “best,” approach happens to be the DAA but this may not hold true for the surgeon who has spent their career performing hip replacements through a posterior approach. It simply all depends on the surgeon’s proficiency with their chosen approach. Total hip arthroplasty is one of the most successful surgeries in all of medicine and a patient can expect an excellent outcome, a high chance of 15-20-year (or longer) survivorship without reoperation and predictable pain relief despite which approach is used.

Ultimately, the concept of achieving a perfect total hip replacement is but an ideal that I will continue to chase.

-Darren Herzog MD