Thank You to Dr. Mast for allowing me to post his entire article.
The Anterior Approach for Hip Replacement is a technique, which is rapidly gaining interest by both patients and practitioners alike. Benefits include a low dislocation rate, improved control of component positioning and an easier and less complicated recovery.
Dr. Mast has been performing Anterior Hip Replacement since 2007. He has authored articles published in peer-reviewed journals on both primary and revision hip replacement performed through this technique. Dr. Mast was the first surgeon in San Francisco performing this technique, and remains one of a select few nationally with proficiency in the technique to apply it for complex primary and revision hip replacement.
Anterior Approach Total Hip Replacement
The Anterior Approach Hip Replacement, or Direct Anterior Hip is a surgical procedure that is gaining worldwide acceptance as an alternative technique to standard hip replacement. A current conservative estimate is that 20% of hip surgeons are now utilizing this technique in select patients for primary hip replacement.
The Anterior Approach implies an approach from the front, as opposed to a more traditional side approach to the hip. The hip is accessed in a naturally occurring interval between muscles as opposed to cutting or splitting through them. The technique uses the same implants as traditional hip replacement or resurfacing procedures.
What are the Advantages of Anterior Approach Total Hip Replacement?
The Anterior Approach for hip replacement offers some unique advantages over traditional techniques. Advantages of the anterior approach include a quick recovery, a low dislocation rate, and a improved surgeon control of implant position.
Most traditional hip replacements are generally done with the patient lying on his/her side. The approach and incision is made from the side or lateral aspect of the patient. Nearly all of the techniques require that the gluteal muscles to be cut or split. These muscles are some of the most powerful in the body and are required to walk with a limp-free gait. Surgery that injures these muscles put the patient at risk for a longer recovery or a permanent limp. The Anterior Approach preserves the gluteal muscles which makes recovery quite fast. Many patients can leave the hospital after a short overnight stay, or even the same day. Many begin walking immediately. Normal stair climbing and more athletic pursuits commonly resume in a matter of days as opposed to weeks or months with standard techniques.
A common problem of traditional hip replacement surgery is dislocation. This is a problem where the ball “jumps” out of the socket. The prosthesis comes uncoupled deep within the body. The patient has agonizing pain and generally is unable to get up off of the floor to walk. Generally this occurs when the patient goes to sit in a low chair or on a toilet. In some cases it happens when the patient bends over or rotates their leg. Generally the patient must have the prosthesis “put back in” by a trained medical provider, this procedure is called a “closed reduction”
While having a dislocation does not always mean the hip will go on to have a bad outcome, if dislocations become recurrent then repeat surgery is required to hold the hip in place. There is debate over the actual dislocation rate in traditional hip replacement surgery. In the case of a very good surgeon, with modern implants one may expect very low dislocation rates. However a recent study showed that dislocation still exists as the most common cause of revision surgery in the US.
The Anterior Approach has some advantages in dealing with dislocation. During the anterior approach the muscles that support the hip are generally left intact. By leaving these important structures intact, the hip is more stable and less likely to dislocate. Studies have demonstrated very low dislocation rates with the technique.
Commonly following traditional hip replacement the patient is told not to bend at the hip or rotate the leg for six or eight weeks following surgery. These positional restrictions are commonly called “hip precautions”. With anterior approach hip replacement hip precautions are generally not required because the muscles around the hip are left intact. When these muscles are cut as in traditional hip replacement, a surgeon may employ hip precautions to protect the surgical repair of these muscles.
Likely the strongest reason for the growth of the anterior hip replacement nationally is that it produces a reliably well positioned hip. A common problem with all minimally invasive techniques of hip replacement has been problems with getting the implants correctly positioned. With reduced visualization it is no small task to get things like cup position or leg length correct. The anterior approach allows the patient to be operated while lying on their back. This facilitates the use of X-ray in surgery. The table that is commonly used for anterior hip replacement is made of carbon fiber allowing one to shoot an X-ray through it. By using the anterior approach and X-ray to guide the surgeon, the final product of a well-positioned hip can be reliably achieved.
What are the Disadvantages of Anterior Approach Hip Replacement
The biggest disadvantage of the anterior approach for hip replacement is that it has a significant learning curve for most surgeons. The technique is difficult compared with traditional approaches. It takes a surgeon many cases to become proficient with the technique to avoid complications. Some studies have advocated that a minimal case exposure of 100 cases is required before a surgeon may be considered proficient in the technique. Complications rates between anterior hip replacement and traditional hip replacement are comparable. Unfortunately, in the hands of surgeons with inadequate training or exposure to the technique, significant and severe complications can be expected. Thankfully, courses and opportunities for advanced study in anterior approach hip replacement are increasingly available to surgeons so that they may better their training and exposure in a safe and monitored environment.
Nerve injury can be a significant and life-altering complication of both traditional hip replacement and anterior approach hip replacement. In cases where the sciatic or femoral nerve are injured there is generally a component of injury which makes it hard to move the leg or foot. This is called a “palsy” or “foot drop”. There doesn’t appear to be an increase of this rare complication using the anterior approach.
Nearly all patients undergoing anterior approach hip replacement have some injury to a sensory nerve that innervates the top of the thigh. About 80 percent of patients undergoing anterior hip replacement report some numbness to touch along the top of the thigh next to the incision. This is largely due to retraction of a nerve called the LFCN, or lateral femoral cutaneous nerve of the thigh. This nerve gives sensation to the top of the thigh. This nerve lies immediately adjacent to the incision in anterior hip replacement. During the procedure, the nerve is stretched which leads to some numbness. In general these symptoms diminish over time. However, if tested there will usually be some residual numbness next to the incision. There is no functional limitation as it relates to this numbness experienced after surgery. Most patients are quite happy with their hip function, but when questioned report having some numbness near the incision.
Femoral fracture is a complication of hip replacement that can occur with any approach. With the anterior approach, exposure of the femur can sometimes be challenging. There have been higher reported rates of femoral fracture with the anterior approach. In the obese or very muscular patient, or in those with severe osteoporosis may make this more likely to occur. The risk of femoral fracture is experience dependent, meaning the more cases a surgeon has done, the less likely a fracture will occur. Again, the lowest risk for fracture is in the hands of surgeons with numerous case experiences.
If a femoral fracture occurs during anterior approach surgery, the key to a good outcome is prompt recognition of the complication. The most common treatment is to pass a cable around the femur and secure it before reseating the implant. The cable secures the fracture and prevents its further displacement. With this treatment most patients can go on to have very good outcomes.
While complications can occur with any technique, the anterior approach for hip replacement is an overwhelmingly successful procedure. A thoughtful discussion with your surgeon about the risks and benefits as they relate to your specific case is warranted.
How long is the recovery for Anterior Hip Replacement surgery?
Various factors influence the recovery time for hip replacement surgery. Basic questions like: “How ‘in shape’ are you?”, “How far can you walk”, or “how many other medical conditions do you have?” all play a role in how long your recovery will be.
In general, a healthy patient with few or no coexistent medical conditions can expect to be out of the hospital in 24 hours. By the time they go home they will be able to walk with a cane, climb stairs independently and able to do most activities of daily living with little or no help. We encourage patients to prepare the home so as to limit trips out of the house for a few days, but no modifications to the home such as raised toilet seats or rails are generally required. The patient can sleep in whatever position is most comfortable. There will generally be no positional restrictions for the leg after surgery.
The patient is generally on a cane for a few days to a few weeks. We encourage walking. When the patient can walk well without the cane they may discard it.
Most patients are able to return to driving once they have stopped narcotic pain medication and have recovered full function of the extremity. In most cases we are seeing this around 2 weeks of time.
Work may resume when the patients symptoms permit, however, it is important not to discount the need for rest during the recovery phase of surgery. I counsel most patients to take a month off of work duties, but feel free to return earlier if symptoms permit.
While no physical therapy is generally required for this technique, we find that a few visits with outpatient therapy may be helpful in regaining strength and improving gait and flexibility lost during the struggle with hip arthritis.
Impact loading and sports with risk of crashing or falling should be avoided until after three months to avoid shifting or dislodging the implant before the bone has fully attached to the implant. Return to vigorous sport should be supervised by the treating physician or physical therapist.
How do I find an Anterior Hip Replacement Surgeon?
The best anterior hip replacement surgeons are going to be highly experienced with the technique with a vast case experience. This experience is usually developed during a fellowship or advanced training in anterior approach hip surgery. One of the best anterior approach fellowships nationally is under one of the developers of the technique Dr. Joel Matta. Find a listing of the graduates of his program here.
At the Hip and Pelvis Institute at Saint Francis Memorial Hospital we serve patients from Northern California and beyond. Our close proximity to SFO international airport, as well as the general walkability of San Francisco makes it a great place to recover from hip replacement surgery. A variety of payment options are available to cover most insured and cash pay patients. We recommend emailing us to obtain more specific information about your particular needs.