Recent advances are enabling hip replacement to take place with much less disturbance of the muscle and soft tissues around the hip. Along with improvements in anaesthesia, and the implants and instruments used, this is leading to easier and more rapid recovery after hip replacement surgery.

The anterior approach to the hip is not new to orthopedic surgery. This approach has been performed for decades in orthopedics, but it has only recently been applied to hip replacement surgery in North America. This interest has occurred due to advancements in instruments and implants as well as the normal progression that occurs with surgery.

The anterior approach for hip replacement has been adopted by surgeons for a number of reasons. These reasons include:

1. less chance of posterior dislocation due to decreased trauma to the capsule, ligaments and muscles at the back of the hip
2. less pain after surgery due to decreased soft tissue disruption
3. easier rehab after surgery
4. improved precision of implant placement with the use of x-ray during the procedure

The anterior hip replacement procedure is usually performed with a spinal anaesthesia. Reasons for recommending a spinal anaesthetic include:

1. relaxes the muscles about the hip
2. reduce risk of blood clot
3. reduced blood loss during surgery
4. easier transition after surgery where patient remains more aware and in control

The procedure is usually performed with the patient lying flat on the operating table. A skin incision is made over the front/outside at the top of the thigh bone. The size of the incision is kept to a minimum, but made large enough to see what needs to be seen. Pain after surgery is less dependent on incision size, and more on the trauma to soft tissue structures under the skin.

After incising the skin, muscles are spread to gain access to the hip joint. No muscles are removed or detached, allowing faster recovery. The capsule is incised to expose the underlying bones of the hip. The bone is then prepared much the same as a traditional hip replacement. The implants are placed in the bone, using x-ray to decrease the variability in implant positioning. The soft tissues are closed and covered and patient brought to the recovery room.

After surgery, the patient is encouraged to walk and move. There are no restrictions on weight bearing or movement during the recovery time. Pain is the main dictator of activity. Patients are encouraged to place ice over the hip, and elevate the leg above the heart in a lying position to avoid swelling. Discharge home occurs once the patient can go the bathroom and do stairs. Usually the stay in hospital is 1 to 2 nights depending on other medical conditions.

The pain of impingement may progress to the point where it interferes with activities of daily living. Treatment first consists of trying to control the pain with over the counter anti-inflammatory medications and Tylenol. If this does not control the pain sufficiently, surgical treatment may be warranted.

Hip Arthroscopy

Hip arthroscopy involves correcting the cause of impingement and dealing the damage that has occurred the hip labrum as well as possible cartilage of the hip joint. Hip arthroscopy is the most common method of accessing the joint. The procedure allows the surgeon to visualize as well as treat the damaged area. Damage to the labrum is addressed with partial removal and possible repair.

The bony problems leading to this impingement are then addressed. This may involve removing a portion of the bone in the front of the hip socket. X-ray is used during the procedure to remove the correct amount as well as to visualize the motion of the hip during bone shaping.

Bone at the junction of the head and neck of the thigh bone are then visualized, and the bone is shaped to create the proper offset necessary for smooth movement. Again, x-ray and hip motion are used to correctly remove bone in the critical area.

In cases of more severe malposition of the hip socket, a redirecting procedure, called a periacetabular osteotomy (PAO) may be required. This is in more severe cases of impingement where bone removal alone would not adequately address the problem.

The goals of treatment for hip dysplasia are to decrease pain and prevent the early development of degenerative arthritis. Once pain becomes enough to interfere with normal activities, it may be advised to treat the dysplasia surgically.

Surgery is performed to redirect the socket and also rarely the upper femur. The socket is redirected using a periacetabular osteotomy (PAO) or Ganz Osteotomy. In severe cases, the upper femur is also addressed using a proximal femoral osteotomy. This redirection positions the joint such that body weight is spread over a larger area, therefore decreasing pain and slowing the progression of arthritis.

Periacetabular Osteotomy

The PAO is performed with the patient laying flat on the operating table. A spinal or general anesthetic is used during the procedure. An incision is made over the front of the hip, exposing the inside of the pelvis and front of the hip joint. The bone around the socket is then cut. These cuts release the socket from the pelvis, enabling repositioning.

The socket is then repositioned to cover more of the femoral head and is fixed with screws. These screws hold the bone fragments while they heal. This bone healing begins immediately, but doesn‘t have significant strength until 2 to3 months after surgery, similar to fracture healing.

Usually patients stay in the hospital for 3 to 4 days. Therapy begins immediately to strengthen the muscles around the hip joint. Weight bearing is restricted to toe touch, as too much weight bearing too early can cause breakage of the screws and change in the socket position. At six weeks, weight bearing is increased gradually to full as pain permits. Once bone healing has occurred, activity can be resumed unrestricted.

The goals of this surgery are to decrease pain and slow or stop the progression of hip degeneration. This hip socket remains shallow, but is repositioned such that it better supports weight and decreases the damaging strain on the cartilage.