Anterior Approach Hip Replacement

The anterior approach is a step forward in hip arthroplasty

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Hip joint arthroplasty is a surgery to replace the articular part of the hip joint with an artificial joint. The aim is to take the pain away, restore function and preserve anatomy.

Over the last three centuries, treatment of hip arthritis has evolved from rudimentary surgery to modern total hip arthroplasty (THA), which is considered one of the most successful surgical interventions ever developed.

The Anterior approach to hip arthroplasty is not new. Judet first introduced it in France in 1947 and many surgeons have been using this approach world wide successfully for decades.  What is new about the anterior approach is that the surgery is being done through a smaller incision with minimal dissection to the soft tissue using special instruments and a special table to make the surgery less traumatic to the patient allowing faster recovery.

The human joints are defined as being articulation between two or more bone endings. The hip joint is made by articulation between the acetabulum of the pelvis and the femoral head forming a ball and socket type articulation. A layer of smooth soft cushion of articular cartilage covers these bone endings, which provide excellent shock absorption and smooth surface facilitating the movement. With age this layer of cartilage wears off this leads to the development of arthritis resulting in pain, stiffness and deformity.

The Hip Joint anatomically lies closer to the anterior surface of the body than the back, furthermore the anterior muscles around the hip are aligned in a longitudinal direction in line with any planned surgical incision while muscles behind the hip lies in a horizontal direction. Any incision posteriorly to access the hip has to cut these muscles to get to the joint. What is unique about the anterior approach to the hip is that it is a muscle splitting approach where the incision is made between two muscles, the Sartorius and Tensor Facia Lata (TFL) in order to get to the hip joint so no muscle is cut during this surgery it is also an intranervous approach so no nerves are severed during the approach due to the fact that these two muscles are supplied by two different nerves the Sartorius is supplied by the femoral nerve while the TFL is supplied by the Superior Gleuteal nerve so no nerves are crossing the incision line or at risk. All the other approaches to the hip involve either muscle cut; bone resection or the incision is traversing motor nerve fibres supplying important muscles in the region.

The outcome of THA depends on many factors: the patient, the implant, the surgical technique and the approach. The patient factor involves the cause and the severity of arthritis, bone quality, presence of other co morbidities, which may adversely affect healing.

The implant factor involves the type of prosthesis such as cemented or cementless implants, the articulating surface such as ceramic, metal or plastic. Accurately selecting the type of implant and the articular surface according to the patient is very important to get the best outcome.

The surgical technique and approach are very important in determining the outcome of surgery. The anterior approach was developed to try to address some of the common complications that are associated with other approaches to the hip such as Dislocation, leg length discrepancy, abductor dysfunction and to allow early recovery and faster rehabilitation, however one cannot say that the anterior approach is better than other approaches. The best approach is the approach that allows proper positioning of the implant replacing the native hip joint with minimal soft tissue dissection.

Proper training is extremely important to reduce complications and ensure good outcome.

As the posterior structures are maintained when performing the anterior approach this reduces the chance of post-operative dislocation.

The Anterior approach to hip replacement is a true minimal invasive technique as no muscles are being detached or resected. This reduces the amount of trauma to the muscles involved, which are essential for daily hip activities.

The important muscles used in hip function are not damaged when using the anterior approach. The result of this reduced trauma means that patients can return to normal daily activities quickly. A big advantage of the anterior approach is there are little restrictions post operatively. Post-operative restrictions associated with the posterior approach, such as not sitting down in a low chair or not bending down to tie your shoelaces, are not needed as the posterior structures are not damaged using the anterior approach.