The hip is a ball-and-socket joint. The socket is formed by the acetabulum, which is part of the large pelvis bone. The ball is formed by the femoral head, which is the upper end of the thighbone, or femur. The surfaces of both the ball and socket are covered with articular cartilage, a smooth tissue that cushions the ends of the bones and enables them to move with ease. The hip joint is surrounded with synovial membrane, a thin tissue that produces a small amount of fluid to lubricate the cartilage and eliminate nearly all friction during hip movement. The ball and socket are connected by bands of tissue called ligaments (the hip capsule) that provide stability to the joint.
In a total hip replacement, or total hip arthroplasty, the damaged bone and cartilage is removed and replaced with prosthetic components. After removing the damaged femoral head, a metal stem is either cemented or "press fit" into the hollow center of the femur and a metal or ceramic ball is placed on the upper part of the stem, replacing the femoral head. A socket (a durable cup of plastic, ceramic or metal, which may have an outer metal shell) is used to replace the damaged cartilage surface of the acetabulum. Screws or cement may be used to hold the socket in place. Inserting a plastic, ceramic or metal space between the new ball and socket allows for a smooth gliding surface during movement. Many different types of designs and materials are currently used in artificial hip joints. Your surgeon will recommend the most appropriate implants and surgical approach for your needs.
People who benefit from hip replacement surgery often experience one or more of the following: hip pain that limits everyday activities, such as walking or bending; hip pain that is continuous, day, night and even when resting; stiffness in a hip that limits the ability to move or lift the leg; hip pain that is inadequately relieved by anti-inflammatory drugs, physical therapy or walking supports.
Recommendations for this surgery are based on your level of pain and disability, not your age. Although total hip replacements are most common for patients between 50 and 80 years of age, they are successfully performed on patients of all ages, from young adults to the elderly. Before recommending total hip replacement, your orthopaedic surgeon will provide an evaluation based on multiple factors, including: your medical history; a discussion of your level of pain and ability to perform daily activities; a physical examination to assess the mobility, strength and alignment of your hip; and X-rays to determine the extent of damage or deformity in the hip. Occasionally, an MRI scan or other additional testing may be needed. Once the evaluation is complete, your doctor will review the results with you and discuss what method of treatment will be best for relieving your pain and increasing your mobility. Options such as medications, physical therapy or other types of surgery may also be considered.
The decision to undergo hip replacement surgery should be a cooperative one made by you and your family along with your primary care doctor and orthopaedic surgeon. Your doctor will explain the benefits along with any potential risks and complications, both relating to the surgery and that could occur over time. Most people experience a dramatic reduction in pain and a significantly improved ability to perform normal activities, however it is important that you understand what you can realistically expect from this procedure in order to manage the changes it will make in your life. With normal use and activity, the material in the hip replacement impact begins to wear. Excessive activity or being overweight may hasten this wear, causing the replacement joint to become loose and painful. Most orthopaedic surgeons advise against running, jogging, jumping or other high-impact activities. More realistic activities include unlimited walking, swimming, golf, driving, hiking, biking, dancing, and other low-impact activities. By appropriately modifying your activities, your hip replacement can last for many years.
Once the decision to have surgery is made, your orthopaedic surgeon will require some preparations, such as: having a complete physical, including evaluation by your primary care physician or specialist for any chronic medical conditions; making sure any skin infections or irritations are treated; blood donations, in the event you may need it after surgery; medication review and management; weight loss if needed to lessen stress on the new joint; dental evaluation; urinary evaluation; and a variety of tests, such as blood and urine samples, electrocardiogram (EKG), and chest X-ray, as needed.
For after surgery—Although you will be able to walk with crutches or a walker soon after surgery, you will need some help for several weeks with such tasks as cooking, shopping, bathing and laundry. If you live alone, your orthopaedic surgeon's office, a social worker, or a discharge planner at the hospital can help you make advance arrangements for assistance at your home. You may also choose to arrange for a short stay in an extended care facility during your recovery.
There are also modifications to your home that can be made to make navigation easier during your recovery, such as: removal of loose carpets and electrical cords from areas where you walk; handrails along stairways; raised toilet seat; stable chair and firm pillows for chairs, sofas and car, all enabling you to sit with knees lower than hips; safety bars or handrails in shower or bath; stable shower bench or chair for bathing; long-handled sponge and shower hose; a reacher to grab objects; dressing stick, sock aid and long-handled shoe horn for putting on socks and shoes without excessively bending your new hip. You may also find it convenient to set up a recovery center equipped with phone, remote control, reading materials, medications and other items in the area where you spend most of your time.
After admission into the hospital, you will be evaluated by a member of the anesthesia team. The most common types of anesthesia are general anesthesia (you are put to sleep) or spinal, epidural, or regional nerve block anesthesia (you are awake but your body is numb from the waist down). The anesthesia team, with your input, will determine the best option for you. Your surgeon will see you before the surgery and sign your hip to verify the surgical site. The surgical procedure takes 1-2 hours. Your orthopaedic surgeon will remove the damaged cartilage and bone and then position the new implants to restore the alignment and function of your hip.
Following surgery, you will be moved to the recovery room where your recovery from the anesthesia will be monitored for several hours. Once you are awake, you will be taken to your hospital room. You can expect to be in the hospital for 1-2 days. You will feel some pain after surgery, but your surgeon and nurses will provide medication to make you as comfortable as possible. Pain management is an important part of your recovery because feeling less pain will allow you to start moving and get your strength back more quickly. If postoperative pain becomes a problem, speak with your surgeon.
The success of your surgery will depend in large measure on how well you follow your orthopaedic surgeon's instructions regarding home care during the first few weeks after surgery.
Walking and light activity are important to your recovery and will begin the day of or the day after your surgery. Most patients who undergo total hip replacement begin standing and walking with the help of a walking support and a physical therapist the day of surgery. Exercise is a critical component of home care, particularly during the first few weeks after surgery and you should be able to resume most normal light activities within three to six weeks. Some discomfort with activity and at night is common for several weeks. Your physical therapist will help you with specific exercises to strengthen your hip and restore movement for walking and other normal daily activities.
Your doctor will discuss with you what precautions can be taken to avoid problems and complications after surgery, such as taking antibiotics prior to dental work. Warning signs of infection include: persistent fever (higher than 100°F orally); shaking chills; increasing redness, tenderness, or swelling of the hip wound; drainage from the hip wound; or increasing hip pain with both activity and rest. Pain, tenderness, redness or swelling that is unrelated to the incision could indicate a blood clot; while sudden shortness of breath, localized chest pain with coughing, or sudden onset of chest pain can indicate a pulmonary embolism. If you notice potential warning signs, be sure to contact your doctor immediately.
To assure proper recovery and prevent dislocation of the prosthesis, you may be asked to take special precautions—usually for the first six weeks after the surgery. Avoid falls by using a cane, crutches, walker or handrails, or have someone help you until you improve your balance, flexibility, and strength. Your orthopaedic surgeon and physical therapist will help you decide which assistive aides will be required following surgery, and when those aides can safely be discontinued.
Also: do not cross your legs, do not bend your hips more than a right angle (90°), do not turn your feet excessively inward or outward, and use a pillow between your legs at night when sleeping until you are advised by your orthopaedic surgeon that you can remove it. Your surgeon and physical therapist will give you more instructions prior to your discharge from the hospital.
The complication rate following hip replacement surgery is low, with serious complications occurring in less than 2% of patients. Among these are: minor infections; deep infections; blood clots in leg veins or pelvis; leg-length inequality; dislocation; implant dislocation; loosening and wear of implant; nerve and blood vessel injury; bleeding; fracture; stiffness; risks of anesthesia; and in a small number of patients, pain continues or new pain occurs following surgery. Occurring even less frequently are major medical complications, such as heart attack or stroke. Chronic illnesses may increase the potential for complications. Although uncommon, these complications can prolong or limit full recovery. Your surgeon may prescribe antibiotics and blood thinners prior to surgery to prevent certain complications.
You may experience numbness in the skin around your incision, as well as some stiffness, particularly with excessive bending. These often diminish with time, and most patients find them minor compared with the pain and limited function they experienced prior to surgery.
Your new hip may activate metal detectors required for security in airports and some buildings. Tell the security agent about your hip replacement if the alarm is activated.
You can protect your hip replacement and extend the life of the implant by participating in a regular, light exercise program to maintain strength and mobility; take special precautions to avoid falls and injuries; inform your dentist of the implant and that you will need antibiotics before any dental procedure; and of course, be sure to see your orthopaedic surgeon as recommended for periodic routine follow-up examinations and X-rays, even if your hip replacement seems to be doing fine.