Total hip replacement is a highly successful, life changing procedure for thousands of patients every year. It is safe, reliable and effective at relieving pain, giving back mobility and restoring quality of life. The technical side of the procedure has undergone massive changes in the last 50 years, with revolutionary new implants and techniques to give long term implant survival and minimal surgical morbidity.
Approaches for total hip replacement
The “approach” for total hip replacement refers to what access route is used through your tissues to allow the surgeon to place the hip implants. Options are:
- Lateral/Hardinge Approach
- Posterior Approach
- Mini Posterior/Super-Path/Direct Superior
- Anterior Approach
“Traditional” Hip Approaches
Sir John Charnley pioneered the modern low friction hip replacement, which is the forefather of the modern hip replacement. He pioneered the modern low friction hip replacement, which is the forefather of the modern anterior and posterior hip replacements. The implants he developed were revolutionary in that they were excellent at relieving pain, and had a long survival. These were inserted via a lateral ‘hardinge’ approach which involved cutting the bone of the femur to gain access to the hip. Whilst the implants were revolutionary, the method of insertion via cutting the femur bone and reattaching it caused significant problems, such as weakness, pain and limping. This approach was lateral modified to cut through the gluteal tendons and muscles of the hip, which avoided the bone problems, but gave rise to new problems of the tendons not healing, persistent weakness and resulting limping. Some surgeons still utilise this ‘modified’ Hardinge approach today. This can be associated with ongoing limping and tendon tears of the hip.
A left sided Charnley hip replacement, with wires holding the cut femur bone in place.
The Posterior Approach was developed later and this largelysolved the problems of tendon and bone healing of the Hardinge and Lateral Approaches. It involves an incision 15-20cm long which is curved over the buttock. It involves splitting the Gluteus Maximus muscle and cutting the small muscles which attach to the back of the hip joint. This is an excellent approach which can easily be extended and is the approach of choice for complex total hip replacement and revision procedures. Potential problems associated with this approach include:
- Splitting and cutting through muscles to gain access to the hip
- Instability of the hip due to de-functioning of the muscle stabilisers of the hip
- Lateral positioning, which makes it difficult to judge leg length and component positioning
- Post operative restrictions on range of motion and longer rehabilitation
Super-Path, Direct Superior and Mini Incision Total Hip Replacement
In a bid to reduce the impact of surgery, ‘mini incision’ total hip replacement was developed which used parts of the more traditional posterior incision and approach, but with reduced muscle and soft tissue damage. The benefit of using this approach is that it can easily be extended to make a posterior approach should difficulties arise.
The anterior approach to the hip joint was first described in 1881 for draining infected hips, and was first used for joint replacement in France approximately 40yrs ago. It involves going between the muscles, rather than cutting them. It is a technically difficult approach that was largely refined by Joel Matta in the USA and Frederic Laude in Paris with the introduction of specialised instrumentation and techniques to make it easier to place large total hip implants through a small incision (8-10cm) at the front of the hip.
Potential advantages of anterior total hip replacement:
- Smaller more cosmetic incisions
- Less muscle and tissue damage as muscles are preserved
- Quicker rehabilitation and recovery
- The ability to take X Rays during the operation to ensure leg length and precise component positioning
- Lower dislocation risk
- No post operative restrictions on range of motion
- Temporary numbness down the outside of the thigh due to nerve stretching
- Higher rate of fracture
- Long learning curve and specialised training required
- The need for specialised instruments and retractors
- Inability to extend the approach
Facts vs Hype in Anterior THR: What the studies show!
There has been a lot of marketing and interest in the approach for total hip replacements. The published studies are less clear on the benefits of one approach over another.
- Rapid Recovery: anterior total hip replacements have been marketed to recover faster, and have less restrictions in early range of motion or activity. Typically this is because these patients are unrestricted in bending, sitting on low chairs, lying on their sides, and driving. This is as opposed to posterior approach patients who have had range of motion restrictions placed upon them. The studies at 3, 6, 12 months do not show any functional difference.
- Improved Stability and Reduced Dislocation Rates: traditional posterior replacements have a dislocation rate of 2-5%, with the anterior approach this has been reduced to 0.2-3% in small studies.
- Tissue Damage: MRI studies comparing Anterior vs Posterior approaches do not show any difference between the radiological tissue damage.
- Fracture Rates: various studies have shown a higher fracture rate with the anterior approach, particularly early in the learning curve, however this does not correlate to any longer term problems.
Which approach is right for me?
Many patients have heard of one approach being ‘better’ than another, and may request a particular approach based upon friends’ experiences, or searching the internet. Quite often, the approach you may have read about will be the most appropriate one for you. However, this needs very careful consideration, as many factors need to be taken into account when deciding upon surgical anterior or posterior hip replacement approach. Patient size and weight, underlying bone structure and deformity, medical problems, previous surgery, the type of implant to be used and the type of anaesthetic all have a bearing upon which is the best option for you.
Which approach does Dr Slattery use?
Dr Slattery has extensive experience with both anterior and posterior approaches for total hip replacement. He has learnt the intricacies of Direct Anterior Total Hip Replacement in both Switzerland and Australia from world leaders in this technique. He is experienced in hip preservation and pelvic trauma surgery from both anterior and posterior approaches. His experience is that with the anterior approach and a rapid recovery pathway patients generally recover much quicker than after a posterior hip replacement, but the most important thing is that the components are inserted precisely with the use of X-ray, which is very difficult to achieve with other approaches.
Approximately 75% of Dr Slattery’s total hip replacements are performed using the anterior total hip replacement technique.
FREQUENTLY ASKED QUESTIONS
Which method of hip replacement is the best – Anterior or Posterior?
Both anterior and posterior hip replacement techniques offer distinct advantages and disadvantages in certain circumstances, meaning one patient may benefit more from anterior, and another from posterior. Dr Slattery will be happy to discuss the difference between the two with you and help guide you towards the one best suited for your circumstances and goals.
What percentage of hip replacement is anterior?
It is estimated that between 15 and 20% of all hip replacements employ the anterior technique. Dr Slattery has experience performing both anterior and posterior hip replacement techniques, ensuring that regardless of the technique required he will be able to consult.
What are the disadvantages of anterior hip replacement?
Anterior hip replacement can result in numbness and has a higher rate of fracture as compared to posterior hip replacement, but the reduced incision size and damage to muscle can overall contribute to a faster recovery time. The anterior approach is not recommended for those with bone weakness (osteoporosis/osteopaenia), as this increases the fracture risk.
Who is a good candidate for anterior hip replacement?
Most patients are good candidates for anterior hip replacement, with patients of nearly all sizes being capable of undergoing the procedure.