APPROACHES

Overview


The anterior approach has gained much publicity recently via the few who are championing it. Much is available on the Internet and it is described as a 'muscle sparing' approach. I have looked into using it, but the complication rate may be higher than the other two below. My perception having seen it on a few occasions being used by surgeons who are skilled at it is that the surgical view gained is not great and it may not be as 'muscle sparing' as advertised. A randomised study on the anterior versus the posterior approach has been performed at my NHS hospital, and this has not yet managed to show any advantages. As a result, I am not completely closed to it, but I do need a bit more convincing before I start using it.

Other approaches used by many surgeons are the lateral (or Hardinge) and the posterior. The Hardinge approach was once the commonest approach for THR, but the issues with it are that it can damage the hip abductors, which can leave the patient with a persistent limp.

As a result of the above, I generally use a posterior approach for THR. This (or variations of it) is now the most common approach used by surgeons in the UK. The benefits are that the surgeon can gain excellent exposure (which makes correct component positioning much easier), and this can be done through a small incision if the patient is suitable. I always promise that I will do the procedure properly through the smallest incision possible, with the least muscle trauma, to perform surgery safely. In some this can be 10cm, in others though it may need to be larger.
 

MORE DETAIL

Hip replacement surgery has been successfully performed for over 50 years. Throughout this time, surgeons have used various different ways to get into the hip, which we term the ‘approach’. They all have pros and cons, and virtually all surgeons feel that the way that they do it is the best! In reality, and despite what is written on the internet by companies or other surgeons, all approaches are generally safe and yield good results during the operation and afterwards. The most important thing is to choose a surgeon who you communicate well with and trust.
 
Currently, the widest utilised approach for a hip replacement in the US and UK is the ‘posterior’ or ‘posterolateral’ (which I use). The reason for this is that the surgeon can gain excellent, clear access to the joint. In skilled hands it can be performed through reasonably small incisions (10cm in thinner patients). However, the great bonus of this approach is that should the surgeon encounter unexpected difficulties, the approach is easily and safely extendable (can be made larger) allowing them to deal with these effectively. This is one of the first principles of surgery, ‘always use an approach which is easily extendable should you encounter the unexpected’!
 
My results using this approach are very good. Intra-operative blood loss is usually around 200 ml (less than a can of cola). Patients get up out of bed on the same day following surgery, and only need to stay in one to two nights. My intra-operative complications are also very low, these being nerve injury, infection, leg length discrepancy (defined as +/- 1 cm), and fracture (bone crack) all being less that 1% each. As the surgery is not unduly prolonged and we get patients up quickly following their operation, our rate of blood clots such as deep vein thrombosis (DVT) in my patients is also less than 1%.
 
Historically, however, the posterior approaches were criticised for having a higher post-operative dislocation rate than the others. Certainly, thirty years ago this was true, but the approach was performed differently then and the surgeons did not repair the joint capsule, which was the major issue. We all do this now, and all high volume hip surgeons who use the posterior approach can quote a dislocation rate of less than 1% for a primary (first-time) hip replacement. (Currently, mine is about 0.5% at the time of writing).
 
The Direct Anterior Approach (DAA) has gained a lot of interest recently and many claims have been made about it online. Many of these are quite emotive, such as being ‘muscle-sparing’ and ‘minimally invasive’ etc. There are also claims that the post-operative dislocation rates are lower than other approaches. As a patient, I can understand why this kind of marketing is effective and why patients are led to think that it is the best approach for hip replacements.
 
In reality, the vast majority of the claims made about DAA are untrue or unproven. The claims that have been made is that it’s tissue sparing, there is less pain, and faster recovery. However, there is little evidence to support these.
The disadvantages of the anterior approach are that often a special table is needed, as is intra-operative x-ray. The femoral exposure can be difficult (particularly in male and heavyset patients); it also increases operating time.
 
In a study of the anterior versus the posterior approach (Meneghini, CORR, 2006) the researchers found muscle damage with both approaches. The muscle damage in the anterior approach was significantly more than posterior. A different study by Pilot (Injury, 2006) looked at another way to look at muscle damage, H-FABP (heart-type fatty acid binding protein), which is a muscle protein. You can evaluate the levels of muscle damage based on the levels of this protein. There was no difference in the posterolateral versus the anterior approach. Post-operative MRI has also failed to show any reduced muscle damage following DAA compared to posterior approaches.
 
Complications are higher with DAA. Regarding dislocation, several large series of anterior approaches to the hip showed roughly the same thing: 0.96% (Siguier), 0.61% (Matta), 1.3% (Kennon), 1.5% (Sariali). As mentioned above, these are all (at best) comparable or higher than mine using the posterolateral approach. Joel Matta is the biggest advocate of the DAA in the U.S. He has quoted a 2.4 % fracture rate with the anterior approach, which is much greater than we see with the posterior approach.
 
The anterior approach is also associated with lateral femoral cutaneous nerve injury. In a paper by Goulding (CORR, 2010) 80% of the patients noted numbness in the distribution of that nerve. And not all of those patients fully recovered. In a paper by Woolson (Journal of Arthroplasty, 2009) looking at surgeons using this technique the complication rate was 9% and the surgical time was at least two thirds more that of the posterolateral approach.
 
Below is a comparison table to look at:
  
MINIMALLY INVASIVE POSTERIOR APPROACH
DIRECT ANTERIOR APPROACH
  
Position of patient
 
Location & length of incision
 
 
 
Muscle preservation
 
 
 
 
 
Risk of nerve damage
 
 
 
 
Risk of fracture
 
 
 
Intraoperative visualization
 
 
 
 
 
 
Risk of dislocation & hip precautions
 
 
 
Good candidate
 
 
Length of surgery
 
Hospital stay
 
Postoperative
complications
 
Use of medical equipment
 
Use of physical therapy
 
Return to sedentary work
 
Return to physical work
 
Return to sports (light/vigorous)
  
On your side
 
Just behind the hip, along the outer buttock area
4–6 inches.
Larger incisions may be needed for larger patients and those with previous surgery or abnormal anatomy
 
The gluteus maximus muscle is split and does not require repair, as the tendon is not cut.
The piriformis and superior gemeli muscles (2 of 4 external rotators of the hip) are detached and later reattached to bone and will heal over 4–6 weeks.
 
No risk of injury to lateral femoral cutaneous nerve.
Very small risk (<1%) to sciatic nerve from excessive retraction during surgery.
 
 
Low risk of fracture due to easier exposure.
 
 
 
Exposure technique allows direct, full visualization of hip cup and femur.
No intraoperative x-rays needed.
Used predominantly by orthopedic surgeons as it is the simplest approach and provides the greatest patient safety.
 
 
Risk is incredibly low (<1%).
Hip precautions are usually not needed
 
 
 
Majority of patients.
 
 
60–90 minutes
 
2–3 days
 
Risk to normal structures, blood clots to legs or lungs, infection, death, anesthesia risks.
 
Frame or crutch, depending on upper body strength and recovery time, weaning off as strength returns.
 
Generally for 6 weeks
 
2 weeks
 
 
3 months
 
6 weeks/3 months
  
On your back
 
Front of upper thigh
4–6 inches
Larger incisions may be needed for larger patients and those with previous surgery or abnormal anatomy
 
Advocates claim this approach is entirely muscle sparing, which is not exactly the case. See above.
The piriformis muscle is also cut to allow implantation of the new femoral implant. It cannot be reattached from this approach.
 
Higher risk of injury to lateral femoral cutaneous nerve, which supplies sensation to the outer thigh.
Some risk to sciatic and femoral nerves from excessive retraction during surgery.
 
Higher risk of femur and ankle fracture due to more difficult exposure and positioing.
Risk increases in patients with osteoporosis.
 
Technically challenging.
Impaired visualization due to working between muscle planes.
Special surgical table utilized for manipulation of the leg during surgery.
Intraoperative x-rays often needed for implant positioning.
 
Low risk.
Dislocations are usually anterior and can occur with external rotation of the leg during any activity.
Hip precautions usually not needed.
 
Patients who do not have significant hip deformities, flexion contractures or are not significantly overweight.
 
2–3 hours
 
Same
 
Same
 
 
Same
 
 
Same
 
1–2 weeks
 
 
1–3 months
 
1 month/3 months
  
I recently came across a quote from an American surgeon, Dr Sweet, whom I feel puts it in perspective very well:
 
“During my fellowship training in joint replacement surgery at the New England Baptist Hospital in Boston, the anterior “Smith-Peterson” (DAA) hip approach was still popular in part due to the fact that Dr. Smith-Peterson had been a legendary New England surgeon in the pioneering days of early orthopedics. As a result I received considerable training in its use. It was around this time that the anterior approach lost favor with most joint replacement surgeons. The reasons for the demise of the anterior approach were many, and most are outlined above.
 
In summary, though, it was generally felt that risks and complications of the anterior approach outweighed any advantages. It has been clearly shown that there is no difference in recovery time between the two approaches. And with the advent of “large head” hip replacement systems, the single possible advantage of a lowered risk of hip dislocation has effectively been eliminated. As with many things, what is old becomes new as we constantly strive to both reinvent and improve tried and true procedures. Sometimes this leads to better methods of treating patients. And sometimes these “new” recycled methods work no better the second or third time around. What is really new in our modern medical world is the hype and marketing in the lay press of all things new before scientific proof of success is available.
 
My word of advice to patients remains this: Stay focused on the important issue – the long-term results. Pick your surgeon based on reputation, experience, and your feelings of trust and personal connection. Though it is important to discuss new procedures and technology, in the end let the surgeon in whom you place your trust pick what is best for you. All that is new is not necessarily better, and this is especially true of ideas that have that may have had a past history of problems or failures.”