Hospitals & NHS

Direct Anterior Hip Replacement Surgery - the Future?

A growing number of joint replacement surgeons are beginning to perform hip replacement surgery using an anterior approach instead of the traditional posterior approach because of the benefits it has for the patient as well as the provider. It can be safely performed on many patients, as long as they have a low risk of fracture and normal anatomy.  You can see the NICE guidelines relevant to this technique here: Minimally invasive total hip replacement (IPG363)

Jamie Wootton BSc MB BS FRCS, consultant orthopaedic surgeon specialising in joint replacement and joint reconstruction at the Wrexham Maelor Hospital in North Wales, discusses the key points on performing anterior hip replacements and what it can mean for the future.

1.  Difference in surgical technique.

The traditional approach to hip replacement surgery is going through the back, splitting the buttock muscles and pealing back the hip muscles to access the joint. When surgeons employ the anterior approach to hip replacement surgery, they enter the hip through the front part of the joint. “It's not the size of incision that matters - it's what you do inside the body.  When we take the anterior approach, we don’t detach or remove any muscles,” Mr Wootton says. “From a recovery standpoint, that means less pain and quicker return to function.”
The anterior approach is a minimally invasive surgery because you can perform the whole procedure through a 10 centimeter or less incision. When surgeons eliminate the muscle disruption, patients don’t have to go on hip precaution, as other hip replacement patients do, and they can return to regular activity quicker.

2.  Imaging technology.

The use of real-time X-ray guidance perioperatively allows for greater precision. In addition to providing a quicker recovery, the anterior approach can also allow surgeons to more precisely place the implant because they can use real-time X-ray guidance whenever they need it during the operation. “With this equipment, you are watching the procedure on X-ray as you go in so you can see where the implant is going and get it exactly where you want it,” says Mr Wootton. “This gives you better control of their leg length.”

Precision of implant placement is known to be one of the biggest determinants of successful hip replacement outcomes.
Experienced surgeons know how to closely reproduce the patient’s leg length, but with the real time X-ray, they can measure both sides to make sure they are the same length. There have been many cases of hip replacement failures due to leg lengthening issues, but with the minimally invasive anterior approach those complications become nearly extinct.

3. Why the procedure isn’t more widespread.

While the anterior approach may be less invasive and associated with fewer complications, surgeons without extra training in the technique will not be able to perform it in a safe and effective manner.  You have to be committed to doing some extra training to be able to perform it safely and consistently,” says Mr Wootton. “The other issue is that you need to have a specialised operating table/extension to allow you to get to the hip from the front and manipulate the patient's legs during the procedure. Historically, these support devices have been expensive, complex and cumbersome - which is why we have developed our own low-cost, portable device to assist surgeons in adopting this technique.  The hospital has to be committed to getting the table and the surgeon has to commit to the extra training, but it’s a better treatment.”
It’s often hard for surgeons to stay abreast of the most recent treatments and techniques, but it can be worthwhile. The anterior approach may be different, but surgeons can still use the same instrumentation they’ve always used during the surgery. “Just because you’ve done hip replacement surgery the same way over your career doesn’t mean you can’t change,” he says. “Some surgeons won’t and that’s fine, because the posterior approach can still provide a good outcome.”


4. Hospitals benefit from the technique as well. 

From his perspective, Mr Wootton says the extra time in training and the financial investment in the anterior approach is worthwhile because he hasn’t experienced any complications, nerve problems or dislocations from patients undergoing anterior hip replacements. It’s also been his experience that these patients are up walking faster, off pain medication sooner and discharged from the hospital sooner.
“We’ve experienced several whole days decrease in the length of stay, from 6.8 days to just over two,” says Mr. Wootton. “All the way around, the short-term recovery has been quicker and there haven’t been any complications.”

5. Anterior hip replacements are the way of the future. 

"As patients find out more about the advantages associated with anterior hip replacements, they will demand that type of procedure and drive it forward", says Mr Wootton." The technology developed in the past few years has made it an easier and more accessible procedure for surgeons to perform". However, in the future he doesn’t see the procedure becoming much less invasive than it is now, which means further innovation will come from implant design and placement.
“You don’t want to sacrifice good results, and there needs to be a balance between minimally invasive techniques and achieving durable, reproducible results with implants,” he says. “I know the implants I use are durable and I can see patients have a good outcome. It’s the next step forward in what we do as far as hip replacement surgery.”

6.  Our Experience with the Direct Anterior Approach

  • Over 400 cases over 3 years at Wrexham Maelor Hospital

  • 2 cohorts; DAA alone, then DAA with enhanced recovery

  • Mean LOS down from 6.8 to 2.2 days (NJR national average is ~7 days)

  • Unselected patients of ASA 1-4 and BMI up to 41

  • Use of FLOTE leg manipulator also allows additional enhanced recovery protocols

  • 30% of patients go home next day!

7.  What are the Economics?

  • There are ~80,000 primary hip replacements in England and Wales each year. The NHS 'tariff' is ~£8,000 per procedure.
  • If DAA were widely adopted, we estimate that either:
  • The NHS can save (£4,000 x 80,000) = £320 million per annum, or
  • Each hospital can make £4,000 extra profit per procedure done in this way

(This does not take account of the extra savings on Physiotherapy, Occupational Therapy, other social services, working days lost, patient review clinics, reduction in 'bed blocking' from reduced LOS, etc.)

8.  Summary of Hospital Benefits

  • Reduced Cost/ More Profit

  • Reduced Waiting Lists

  • More Flexibility of e.g Bed management

  • Happy patients

  • Enhanced Reputation

  • More Throughput of Cases with the same (or reduced) resources