What Is A Hip Replacement Surgery?

A hip replacement surgery is a surgical procedure that replaces worn out or diseased parts of the hip joints with an implant. This replacement serves to optimize the function of the hip joint allowing the patient to move without pain, stiffness, or discomfort. The replacement can either be complete or partial. This means that the entire joint can be replaced or just a part of the joint can be replaced. These parts could be either the head of the femur or acetabulum, the two parts of the hip joint.

With new information and technology coming up every day, better procedures keep getting discovered. Less invasive procedures, with minimal risk and less recovery time. One of such procedures is anterior hip replacement surgery.

Image of an implant in the hip joint after hip replacement surgery anterior approach.

What is Anterior Hip Replacement surgery?

As the name implies, it describes a hip replacement procedure that is performed through the front of the hip while patients are lying on their back. It is a new surgical technique which preserves muscles and facilitates early mobilisation and accelerated rehabilitation. 

Unlike traditional techniques (posterior or lateral approach), patients who undergo the anterior hip replacement are allowed to squat, kneel and cross their legs due to the low risk of implant dislocation.  

Who benefits from Anterior Hip Replacement Surgery?

An anterior hip replacement surgery is indicated in patients who have hip pain secondary to the following conditions:

- Osteoarthritis
- Hip dysplasia
- Rheumatoid arthritis
- Osteomyelitis
- Avascular necrosis
- Fracture

Anterior vs Posterior Hip Replacement Surgery

The terms ‘anterior’ and ‘posterior’ described the entry point into the hip joint. Once in the hip joint, your orthopaedic surgeon has to perform the fundamentals of hip replacement surgery. This includes removing the worn out or disease parts of the hip and replacing them with well positioned implants. A successful hip replacement surgery is marked by a stable, painless hip with equal leg lengths. 

With the anterior approach, a finger-length incision is positioned obliquely in the front of the groin. Muscles are simply pushed to the side in this muscle-sparing technique to access the hip joint. The anterior hip capsule is repaired after surgery to add to the hip stability. Preserving the muscle and soft tissue envelope around the hip reduces post-operative pain and facilitates early mobilisation. As all posterior structures are preserved and untouched, the risk of posterior hip dislocation is next to nil. 

The posterior approach is the traditional technique which involves a larger skin incision and splitting of the gluteus maximus (buttock) muscle to access the back of the hip. Several other muscles including 3 short external rotator muscles and the piriformis muscles are detached from the femur bone. The posterior capsule and muscle envelope are compromised during surgery which significantly increases the risk of posterior dislocation of the implants. These structures have to be repaired and take time to heal. During this time, patients are advised not to squat, kneel or cross their legs. 

Advantages of Anterior Hip Replacement Surgery

Advantages of the anterior hip replacement surgery include:

• This  muscle-sparing approach avoids cutting through muscles and gently pushes them away instead. This facilitates early mobilisation and accelerated rehabilitation. 
• Patients experience less pain compared to those who undergo traditional hip replacement surgery as less muscles and soft tissue are violated. 
• Early mobilisation on the same day of surgery is the new normal as patients have less pain and more muscle strength with the anterior approach technique. 
• Shorter hospital stay is made possible with early mobilisation, less need for painkillers and more confidence with walking without aids. 
• There are no hip precautions which need to be taken with the anterior approach surgery. This is because the posterior muscles and soft tissue are preserved during surgery. With the posterior approach, the posterior muscles and tissue envelope are compromised and undermined. Patients are therefore not allowed to squat, kneel or cross their legs due to the significant risk of posterior dislocation of the hip if they do so. 

• Limb length discrepancy (LLD) describes a complication where one leg is shorter than the other.  LLD is avoided with the anterior hip replacement surgery with the use of x-rays during surgery and more accurate clinical assessment of leg lengths as patients are lying comfortably on their backs. With traditional techniques, patients undergo their surgery lying on their sides. This makes clinical assessment of leg lengths challenging and more likely to be inaccurate. LLD can lead to an abnormal gait and limping.

Possible Complications with the Anterior Hip Replacement

Dr Mizan Marican of Orion Orthopaedic Surgery routinely performs the Anterior hip replacement surgery on a standard surgical table. He does not use any traction due to the risk of fractures and joint dislocations associated with traction tables. Minor complications include the following: 

• Temporary numbness of the thigh may occur due to stunning of a nerve that supplies the skin of the thigh. This numbness tends to recover within a month or two. The skin nerve is not cut, rather it is pushed to the side with the muscles to allow surgery to proceed. This nerve is known as the lateral femoral cutaneous nerve (LFCN). 
• Limb Length Discrepancy (LLD) is a complication which may occur with any hip replacement procedure, regardless of its approach. To minimise LLD, Dr Mizan performs his anterior replacement surgery with the use of x-rays or even robot-assisted techniques (Makoplasty) to ensure this complication is avoided. It is also much easier to clinically assess the lengths of both legs during surgery with the patient lying on his or her back.  
• With any surgery, big or small, there will be a scar. To allow good healing of the scar and prevent any infections, antibiotics are given before, during and after surgery. Antiseptic is also used to clean the skin before any skin incision is made. 

Reviewing radiographs of the hip joint showing implants after anterior hip replacement surgery.

Conclusion

The anterior hip replacement surgery technique is a muscle-sparing technique associated with less post-operative pain, early mobilisation and accelerated rehabilitation. Without any hip precautions after surgery, patients begin their rehabilitation early and return to their active lifestyles and sporting hobbies with ease of mind and confidence. 

Discuss the anterior hip replacement technique with Dr Mizan to understand its pros and cons. We will help you reclaim your active lives.