The surgical steps of an anterior approach hip replacement differ from the steps of the posterior approach. These differences can have short-term and possibly long-term effects on patients.
Location of Incision
The most obvious difference between anterior and posterior hip replacement surgeries is the location of the incisions:
- Anterior hip replacement surgery uses an incision at the front of the hip. This incision typically starts at the top of the pelvic bone (iliac crest) and extends down toward the top of the thigh. Less commonly, the incision is made horizontally.
- Posterior hip replacement surgery uses a curved incision on the side and back of the hip. The incision curves just behind the greater trochanter, the knobby bit of bone that sticks out at the side from the top of the femur (thigh bone).
The location of the incision determines the where the postsurgical scar will be.
Once the surgical incision is made, the muscles must be pushed aside or cut to access the hip’s ball-and-socket.
- Anterior hip replacement requires the surgeon to work between the muscles, pushing them aside to get to the hip joint. This natural separation allows ready access to the hip joint with minimal or no muscle cutting. The surgeon works in between muscles supplied by different nerves.
- The posterior hip replacement approach requires surgeons to cut muscles and other soft tissue at the back of the hip, including:
- The tensor fascia lata, which is a wide piece of fibrous soft tissue at the top of the outer thigh. It works with the iliotibial band (IT band) to help stabilize the hip and knee.
- The large gluteus maximus muscle, which is attached to the fascia lata. The gluteus maximus allows a person to extend and rotate the thigh outward. It also helps stabilize the pelvis and keep the body erect.
- The external rotators of the hip, which are small, short muscles that connect the top of the femur to the pelvis. These muscles provide hip stability, preventing the femur from dislocating out the back of the hip socket.
Like the posterior approach, the direct lateral approach to hip replacement also requires the cutting of muscles. In that surgical approach, the abductor muscles (gluteus medius and minimus) are affected. Any muscles that are cut during posterior or lateral surgeries are repaired and reattached at the end of the surgery.
Technical Ease of Surgery
All hip replacements require the dislocating the hip and shaping the bones in order to implant prosthetic hip joint components. The anterior approach presents specific challenges, though.
- The anterior approach to hip replacement tends to provide the surgeon with a more limited view of the hip joint during surgery, making the surgery technically challenging, especially for less experienced surgeons.
- The posterior and direct lateral approaches provide the surgeon with a better view of the hip joint.
Because of the technical difficulty associated with anterior hip replacement, adequate surgical training is essential.
Surgical tools and tables have been developed to accommodate anterior hip replacement surgery and make the procedure easier for surgeons. Whether these specialized tools and tables are necessary for better outcomes is a matter of ongoing research.
Understanding the differences between these surgeries can help people decide what surgery, if any, is right for them.