Total Hip Replacement using Direct Anterior Approach (DAA)
What is a total hip replacement (THR)?
Posterior VS Anterior Approach for Total Hip Replacement
With the posterior approach, there is a significant risk of the implants popping out (dislocating) if patients squat or cross their legs.
Modern innovations in orthopaedic surgery have introduced a minimally invasive surgical technique in total hip replacement surgery. The direct anterior approach (DAA) has been widely adopted by orthopaedic surgeons across the world because of the several advantages that it yields over traditional hip replacement methods.
This allows a faster recovery and reduces the risk of posterior dislocation of the hip. After the surgery, patients are allowed to kneel, squat, and cross their legs. Another advantage of the anterior approach is that surgeons can assess the lengths of both legs accurately using X-rays.
- Muscles are pushed to the side during surgery
- Patients lying on their backs (supine) during surgery allows accurate assessment of leg length
- Accurate X-rays are done to assess leg length and implant positioning
- Hip abductor muscles are preserved
- Minimal risks of hip dislocation
What are the risks with the anterior approach?
There is a risk of transient or temporary numbness in the thigh after the surgery due to bruising of the superficial nerves in the thigh (lateral femoral cutaneous nerve). This only affects about 10% of patients and tends to resolve after several weeks.
Patients may also experience an ache in their thigh after the surgery, but this is easily remedied with simple analgesics, physiotherapy, and time. Major complications such as injuries to large blood vessels and nerves are rare, as are fractures of the femur.
At Orion Orthopaedic Surgery, hip replacement surgeries are performed on a simple surgical bed without any traction to prevent major complications such as spiral fractures of the femur and tibia or dislocations of the knee. A blood transfusion is also rarely needed after a hip replacement surgery.
Consultation & assessment
During the surgery
The arthritic hip joint is carefully removed with specialized orthopaedic equipment through the acetabulum (cup side) and replaced with a titanium cup. The femur stem is inserted into the femur bone before the hip is reduced into position. This surgery is performed with the use of X-rays to ensure correct size and optimal positioning of all implants.
The orthopaedic surgeon will stress the hip in various directions during surgery to ensure it is stable and does not dislocate. After all actual implants have been positioned, the hip is washed and cleaned to help prevent any infection. The soft tissue is then closed in multiple layers before dressings are applied.
The worn-out cartilage is scraped and reamed out to make way for the new cup.
We use X-rays to ensure that the cup is appropriately sized and placed in an optimal position (medial enough with adequate inclination and anteversion).
The jagged metal is a trial implant. Like buying shoes, we ensure this implant is sized appropriately and placed optimally for you.
Once satisfied, we replace the trial implants with actual implants. X-rays help to ensure there are no fractures around the hip, the implants are well-sized and positioned for you.
A bikini skin incision is an oblique incision about 9 to 10cm around the groin crease.
A standard post-operative X-ray is performed to assess the new hip.
After a total hip replacement surgery via the direct anterior approach, patients are encouraged to walk as much as possible. No hip precautions are imposed and patients are allowed to kneel, squat and cross their legs as needed.
Patients are informed that they are not to go for any bungee jumping activities as the strong pull of the rope at their ankles will likely dislocate their hips. It is also best to avoid certain forms of vigorous massage which involves forceful traction of their legs.
Most of my patients are able to drive after 3 weeks - this is mostly based on individual confidence in their own abilities. Simple analgesics like paracetamol or anti-inflammatories are given after surgery to facilitate early mobilization.
I am always happy to hear stories from past patients returning to their favourite physical activities which they were not able to do before surgery. Simple activities such as caring for their grandchildren or having lunch out with old friends are important events that raise our spirit and form the important parts of our lives.
Bilateral total hip replacement performed for hip athritis secondary to dysplasia (shallow hip sockets) to facilitate a more meaningful rehabilitation in patients with several disease in both hips.
How long do these implants last?
The longevity of your implants depends on the quality of the implants, whether they were placed in an optimal position, your age, body weight and the types of physical activities you indulge in.
The hip implants used in Singapore are made in USA and the manufacturing quality and storage techniques have drastically improved over the years. Several countries around the world maintain joint registries to monitor all implants that have been used, allowing for a bird’s eye view on things in the case of defective products or implants.
A majority of patients undergo hip replacement surgery in their early 60s and above. In this phase of life, most patients are retired and do not engage in highly strenuous activities such as marathon running. The stress placed on their implants are therefore mild to moderate. Based on the average lifespan of Singaporeans which is about 85 years, we do expect most implants to be long-lasting. This is especially so if there are no infections, falls or fractures sustained by the patient.
Speak to our orthopaedic surgeon if you are having pain and trouble with your hips. We are here to help you on your journey.
It is possible. The conventional route will involve taking your complete medical history into consideration, as well as perform a thorough medical examination and an X-ray examination. Often this process is adequate to diagnose hip arthritis. An MRI scan of the hip may also be required if the arthritis is in its early stages.
Non-surgical management of hip arthritis include the use of anti-inflammatory medication, physiotherapy, and a slight change in daily activities. An injection containing a local anaesthetic and a small dose of steroid or lubrication is administered into the hip joint occasionally to help temporarily alleviate the pain.
If the hip pain and loss of functions persists despite the management measures put in place, your orthopaedic surgeon will then discuss surgery for the symptoms.
When do you consider hip preservation surgery?
In young patients with hip pain and arthritis, hip preservation surgery is more of an ideal procedure. Depending on the underlying cause of hip pain, the orthopaedic surgeon may decide between arthroscopic labral repairs and microfractures for arthritis, or core decompression surgery for early avascular necrosis (death of bone tissue) of the hip.
Where patients are older or if hip preservation surgery is not an appropriate or practical method, a total hip replacement is preferred.