Hip Replacement

The hip is a ball-and-socket joint has the following structures:

• Acetabulum of the pelvis
• Head of the femur
• Ligaments of the hip joint

The hip joint is a ball-and-socket synovial joint where the socket is the acetabulum and the ball is the femoral head. The hip joint connects the pelvis with the femur, which joins the axial skeleton and the lower extremity. The adult hip bone forms by the fusion of the ischium, the ilium, and the pubis, by the end of the teenage years. The 2 hip bones form the bony pelvis, along with the sacrum and the coccyx, and are joined anteriorly by the pubic symphysis.

Several strong ligaments help in holding the head of the femur within the acetabulum. They are named as per their attachments:

• The iliofemoral ligament joins the front of the ilium to the femur. It is in shape of a fan looks like an inverted Y and is sometimes known as the Y ligament of Bigalow.
• The pubofemoral ligament connects from an area on the front region of the pelvis called the pubis and attaches to the femur.
• The ishchiofemoral ligament joins to a bony area on the rear side of the pelvis and then attaches to the femur bone.
• The articular capsule, which is very dense and strong, encompasses the entire acetabulum.

The stability of the knee is governed by four main ligaments in general. The ones on each side of the knee (but in fact outside the joint) are known as collateral ligaments. The other two are more centrally located ligaments within the joint known as anterior and posterior cruciate ligaments.

---

In the hip replacement process, hip joint is replaced by a prosthetic implant through a surgery. Hip replacement surgeries are of two types- total replacement or a hemi (half) replacement. The hemi replacement surgery is beneficial in relieving arthritis pain or for fixing several physical joint damages as part of hip fracture treatment. In case of total hip replacement, both the acetabulum and the femoral head are replaced while hemiarthroplasty generally only replaces the femoral head. Hip replacement is at present the most successful and reliable orthopaedic operation with 97% of patients reporting improved outcome.

The total hip replacement is also called a hip arthroplasty and in this procedure the head of the femur is removed along with the surface layer of the socket in the pelvis.

• The head of the femur is situated within the pelvis socket. It is removed and a metal ball and stem are placed instead. This stem fits into the shaft of the femur.
• The socket is replaced with a plastic or a metal and plastic cup.

Doctors have been using various materials into diseased and painful hip joints for centuries to relieve pain. Until 1960, the pain could not be relieved. At that time, the metal ball and plastic socket for the replacement of the hip joint was introduced. Currently, more designs of the artificial components used in THR are available and they are stronger.

The artificial components of the hip joint come in many different shapes, sizes, and designs. Mostly, they are made of chrome, cobalt, titanium, or ceramic materials. Some surgeons are also using custom-made components to improve the fit in the femur.

General rules of total hip replacement that the patient needs to follow are:

• The patient receiving a total hip should avoid bending the hip beyond 90 degrees in the first six to eight weeks after the operation. In order to achieve this, the patient should keep knees below the hips when sitting. Sitting on a small pillow can help with this positioning. The individual should avoid sitting in sofas or couches which may cause excessive bend at the hip.
• Avoid crossing the surgical leg over the non-surgical leg. When sitting, it is good advice to keep the legs three to six inches apart.
• Avoid turning the operated leg inward, i.e. pigeon-toed.
• Avoid bending over from the hip to reach the floor.

The care that needs to be taken after the surgery begins with a team of health professionals within the hospital. Those closely involved with the postoperative total hip patient are:

• Nurses
• Physical Therapists
• Respiratory Therapists
• Occupational Therapists

The nursing staff checks and observes vital signs and sensation in the lower extremities and they further document it for the physician. Antibiotics are frequently administered every eight hours, for two to three days, to reduce the risk of infection.

The surgical incision is observed closely for:

• Excessive drainage
• Proper initial healing
• The need for changing of sterile dressings

---

The Respiratory Therapist

The respiratory therapist is vital at this stage for:

• Instruction in deep breathing exercises and coughing to help prevent complications, like congestion or pneumonia.
• Instruction in the use of a bedside device called an incentive spirometer to assist in deep breathing exercises. It is important to use this device and perform deep breathing exercises to reduce the risk of lung complications by removing excess secretions that may settle in the lungs during surgery.

Shortly after surgery the physical therapist addresses:

• Circulation - The acute care physical therapist in the hospital guides the patient in early stage exercises like moving the ankles up and down to stimulate circulation and prevent clots.
• Range of motion - The physical therapist will guide the patient to do exercises which can help improve hip range of motion.
• Mild strengthening - After the surgery, the total hip patient should take help of the hospital physical therapist to advance range of motion to the hip and to initiate muscle strengthening. With the help of this, the patient will progress into becoming independent in walking, climbing stairs, getting in and out of bed, and performing exercises to improve the range of motion and strength of the hip. This initial rehabilitation generally takes 5-7 days. During this time, patients may experience discomfort while walking and exercising. To address this problem, pain medication will be ordered by the doctor as needed.
• Gait training - With the help of the physical therapist the patient is made to walk short distances using crutches or a walker. This not only promotes range of motion and strength but is also important for endurance and stamina. Weight bearing will depend on the nature of the implant fixation. If cement was used on both the socket and the femur side, weight bearing as tolerated using a walker will be instituted. If the joint is cement less, weight restrictions will be recommended for 4 to 6 weeks. It is critical for patients to adhere to the weight bearing status given to them following surgery.

By performing this exercise well, the patient can improve muscle activity of the hamstrings. This also helps increase the amount of knee flexion. The physical therapist will record the amount of flexion and extension for a daily report on the patient's progress to be reviewed by the physician.

Lie in bed on the back, keep legs straight and together and arms at the side.

• Slide the foot of the surgical limb toward the buttock to a point where a mild stretch is felt.
• Stay in this position to a count of ten and slowly return to the starting position.

---

The Occupational Therapist

The job of the occupational therapist is to evaluate and address the safe and independent everyday activities of the patients such as dressing, bathing, and caring for his or herself after hip surgery. The therapist observes the amount of comfort of discomfort while performing daily chores. The occupational therapist guides patients how to use equipment that prevents excessive bending of the new hip.

Each individual envisioning hip replacement should consider alternatives with his or her physician to get to the possible options. Some alternatives to hip replacement are as follows:

• Medication
• Femoral osteotomy
• Arthrodesis

---

Medication

Medication can often help control pain and provide comfort to the person so that he or she can have a normal life. In such case when the hip range of motion is functional, the decision to wait on surgery may be reasonable.

---

Femoral Osteotomy

Developmental hip dysplasia or alignment problems of the hip may begin. A femoral osteotomy may be suggest if the hip weight bearing area can be widened for a better fit. In this process the femur is cut to realign the hip. However, recovery following femoral osteotomy takes longer than with joint replacement.

---

Arthrodesis

In Arthrodesis the pain is relieved by fusing the head of the femur head to the acetabulum. It has lesser limitations as compared to a hip joint replacement. This procedure can be very effective if the individual's back is functioning and without symptoms because much of the movement lost from the hip joint come from the back. Surgerical fixation with a plate and screws is generally required in the procedure and occasionally a cast is required to use while healing continues. An arthrodesis can be converted to a total hip replacement later on if required.