TOTAL HIP REPLACEMENT
Whether you have just begun exploring treatment options or have already decided with your orthopedic surgeon to undergo hip replacement surgery, this information will help you understand the benefits and limitations of total hip replacement. This article describes how a normal hip works, the causes of hip pain, what to expect from hip replacement surgery, and what exercises and activities will help restore your mobility and strength and enable you to return to everyday activities.
If your hip has been damaged by arthritis, a fracture or other conditions, common activities such as walking or getting in and out of a chair may be painful and difficult. Your hip may be stiff and it may be hard to put on your shoes and socks. You may even feel uncomfortable while resting.
If medications, changes in your everyday activities, and the use of walking aids such as a cane are not helpful, you may want to consider hip replacement surgery. By replacing your diseased hip joint with an artificial joint, hip replacement surgery can relieve your pain, increase motion, and help you get back to enjoying normal, everyday activities.
First performed in 1960, hip replacement surgery is one of the most important surgical advances of the last century. Since 1960, improvements in joint replacement surgical techniques and technology have greatly increased the effectiveness of total hip replacement. Today, more than 193,000 total hip replacements are performed each year in the United States. Similar surgical procedures are performed on other joints, including the knee, shoulder, and elbow.
The hip is one of the body’s largest weight-bearing joints. It consists of two main parts: a ball (femoral head) at the top of your thighbone (femur) that fits into a rounded socket (acetabulum) in your pelvis. Bands of tissue called ligaments (hip capsule) connect the ball to the socket and provide stability to the joint.
The bone surfaces of the ball and socket have a smooth durable cover of articular cartilage that cushions the ends of the bones and enables them to move easily.
A thin, smooth tissue called synovial membrane covers all remaining surfaces of the hip joint. In a healthy hip, this membrane makes a small amount of fluid that lubricates and almost eliminates friction in your hip joint.
Normally, all of these parts of your hip work in harmony, allowing you to move easily and without pain.
Common Causes of Hip Pain and Loss of Hip Mobility
The most common cause of chronic hip pain and disability is arthritis. Osteoarthritis, rheumatoid arthritis, and traumatic arthritis are the most common forms of this disease.
- Osteoarthritis usually occurs in people 50 years of age and older and often individuals with a family history of arthritis. It may be caused or accelerated by subtle irregularities in how the hip developed. In this form of the disease, the articular cartilage cushioning the bones of the hip wears away. The bones then rub against each other, causing hip pain and stiffness.
- Rheumatoid arthritis is an autoimmune disease in which the synovial membrane becomes inflamed, produces too much synovial fluid, and damages the articular cartilage, leading to pain and stiffness.
- Traumatic arthritis can follow a serious hip injury or fracture. A hip fracture can cause a condition known as osteonecrosis. The articular cartilage becomes damaged and, over time, causes hip pain and stiffness.
Is Hip Replacement Surgery for You?
Whether to have hip replacement surgery should be a cooperative decision made by you, your family, your primary care doctor, and your orthopaedic surgeon. The process of making this decision typically begins with a referral by your doctor to an orthopaedic surgeon for an initial evaluation.
Although many patients who undergo hip replacement surgery are 60 to 80 years of age, orthopaedic surgeons evaluate patients individually. Recommendations for surgery are based on the extent of your pain, disability, and general health status-not solely on age.
You may benefit from hip replacement surgery if:
- Hip pain limits your everyday activities such as walking or bending.
- Hip pain continues while resting, either day or night.
- Stiffness in a hip limits your ability to move or lift your leg.
- You have little pain relief from anti-inflammatory drugs or glucosamine sulfate.
- You have harmful or unpleasant side effects from your hip medications.
- Other treatments such as physical therapy or the use of a gait aid such as a cane do not relieve hip pain.
The Orthopaedic Evaluation
Your orthopaedic surgeon will review the results of your evaluation with you and discuss whether hip replacement surgery is the best method to relieve your pain and improve your mobility. Other treatment options such as medications, physical therapy, or other types of surgery also may be considered. Your orthopaedic surgeon will explain the potential risks and complications of hip replacement surgery, including those related to the surgery itself and those that can occur over time after your surgery. The orthopaedic evaluation will typically include:
- A medical history, in which your orthopaedic surgeon gathers information about your general health and asks questions about the extent of your hip pain and how it affects your ability to perform every day activities.
- A physical examination to assess hip mobility, strength, and alignment.
- X-rays (radiographs) to determine the extent of damage or deformity in your hip.
Occasionally, blood tests or other tests such as MRI (magnetic resonance imaging or bone scanning may be needed to determine
What to Expect From Hip Replacement Surgery
An important factor in deciding whether to have hip replacement surgery is understanding what the procedure can and cannot do.
Most people who undergo hip replacement surgery experience a dramatic reduction of hip pain and a significant improvement in their ability to perform the common activities of daily living. However, hip replacement surgery will not enable you to do more than you could before your hip problem developed.
Following surgery, you will be advised to avoid certain activities, including jogging and high-impact sports, for the rest of your life. You may be asked to avoid specific positions of the joint that could lead to dislocation.
Even with normal use and activities, an artificial joint (prosthesis) develops some wear over time. If you participate in high-impact activities or are overweight, this wear may accelerate and cause the prosthesis to loosen and become painful.
Preparing for Surgery
If you decide to have hip replacement surgery, you may be asked to have a complete physical examination by your primary care doctor before your surgical procedure. This is needed to assess your health and identify conditions that can interfere with your surgery or recovery.
Several tests may be needed to help plan your surgery: blood and urine samples may be tested and a cardiogram and chest x-rays (radiographs) may be obtained.
Preparing Your Skin
Your skin should not have any infections or irritations before surgery. If either is present, contact your orthopaedic surgeon for a program to improve your skin before surgery.
You may be advised to donate your own blood prior to surgery. It will be stored in the event you need blood after surgery.
Tell your orthopaedic surgeon about the medications you are taking. Your orthopaedist or your primary care doctor will advise you which medications you should stop or can continue taking before surgery.
If you are overweight, your doctor may ask you to lose some weight before surgery to minimize the stress on your new hip and possibly decrease the risks of surgery
Although infections after hip replacement are not common, an infection can occur if bacteria enter your bloodstream. Because bacteria can enter the bloodstream during dental procedures, you should consider getting treatment for significant dental diseases (including tooth extractions and periodontal work) before your hip replacement surgery. Routine cleaning of your teeth should be delayed for several weeks after surgery.
Individuals with a history of recent or frequent urinary infections and older men with prostate disease should consider a urological evaluation before 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 to have someone assist you at your home. A short stay in an extended-care facility during your recovery after surgery also may be arranged.
The following is a list of home modifications that will make your return home easier during your recovery:
- Securely fastened safety bars or handrails in your shower or bath
- Secure handrails along all stairways
- A stable chair for your early recovery with a firm seat cushion (that allows your knees to remain lower than your hips), a firm back, and two arms
- A raised toilet seat
- A stable shower bench or chair for bathing
- A long-handled sponge and shower hose
- A dressing stick, a sock aid, and a long-handled shoe horn for putting on and taking off shoes and socks without excessively bending your new hip
- A reacher that will allow you to grab objects without excessive bending of your hips
- Firm pillows for your chairs, sofas, and car that enable you to sit with your knees lower than your hips
- Removal of all loose carpets and electrical cords from the areas where you walk in your home
You will most likely be admitted to the hospital on the day of your surgery. Prior to admission, a member of the anesthesia team will evaluate you. The most common types of anesthesia for hip replacement surgery are general anesthesia (which puts you to sleep throughout the procedure and uses a machine to help you breath) or spinal anesthesia (which allows you to breathe on your own but anesthetizes your body from the waist down). The anesthesia team will discuss these choices with you and help you decide which type of anesthesia is best for you.
The surgical procedure takes a few hours. Your orthopedic surgeon will remove the damaged cartilage and bone and then position new metal, plastic, or ceramic joint surfaces to restore the alignment and function of your hip.
The prosthetic implant used in hip replacement consists of different parts, the acetabular cup, the femoral component and the particular interface. Options exist for different patients and indications. Correct selection of the prosthesis is important.
The Acetabular cup is the component which is placed into the acetabulum (hip socket). Cartilage and bone are removed from the acetabulum and the acetabular cup is attached using friction or cement. Some acetabular cups are one piece, others are modular. One piece (monobloc) shells are either polyethylene or metal, they have their articular surface machined on the inside surface of the cup and do not rely on a locking mechanism to hold a liner in place. A monobloc polyethylene cup is cemented in place while a metal cup is held in place by a metal coating on the outside of the cup. Modular cups consist of two pieces, a shell, and liner. The shell is made of metal, the outside has a porous coating while the inside contains a locking mechanism designed to accept a liner. Two types of porous coating used to form a friction fit are sintered beads or a foam metal design to mimic the trabeculae of cancellous bone. Additional fixation is achieved as the bone grows onto or into the porous coating. Screws can be used to lag the shell to the bone providing even more fixation. Polyethylene liners are placed into the shell and connected by a rim locking mechanism, ceramic and metal liners are attached with a Morse taper.
The femoral component is the component that fits in the femur (thigh bone). Bone is removed and the femur is shaped to accept the femoral stem with the attached prosthetic femoral head (ball). There are two types of fixation, cemented and uncemented. Cemented stems use acrylic bone cement to form a mantle between the stem and to the bone. Uncemented stems use friction, shape and surface coatings to stimulate bone to remodel and bond to the implant. Stems are made of multiple materials, titanium, cobalt chromium and stainless steel and they can be monolithic or modular. Modular components consist of different head dimension and/or modular neck orientations, these attach via a Morse taper. These options allow for variability in leg length, offset and version. Femoral heads are made of metal or ceramic. Metalheads, made of cobalt chromium for hardness, are machined to size and then polished to reduce their coefficient of friction and minimize the wear they generate. Ceramics heads have a lower coefficient of friction than cobalt chrome however they are more brittle. But with recent advances in tribology, even this problem is resolved called delta ceramic.
The particular interface is not actually part of either implant, rather it is the area between the acetabular cup and femoral component. The articular interface of the hip is a simple ball and socket joint. Size, material properties and machining tolerances at the articular interface can be selected based on patient demand to optimize implant function and longevity while mitigating associated risks. The interface size is measured by the outside diameter of the head or the inside diameter of the socket. Common sizes of femoral heads are 28 mm, 32 mm and 36 mm, while a 22.25 mm was common in the first modern prostheses, now even larger sizes are available 38–54+. Larger diameter heads lead to increased stability and range of motion while lowering the risk of dislocation. At the same time, they also are subject to higher stresses such as friction and inertia. Different combinations of material have different physical properties which can be coupled reduce the amount of wear debris generated by friction. The typical pairing of materials includes metal on polyethylene (MOP), metal on crosslinked polyethylene (MOXP), ceramic on ceramic (COC), ceramic on crosslinked polyethylene (COXP) and metal on metal (MOM). Each combination has different advantages and disadvantages.
Your orthopedic surgeon will choose the type of prosthesis that best meets your needs. After surgery, you will be moved to the recovery room where you will remain for 1 to 2 hours while your recovery from anesthesia is monitored. After you awaken fully, you will be taken to your hospital room.
Your Stay in the Hospital
You will usually stay in the hospital for a few days. After surgery, you will feel pain in your hip. Pain medication will be given to make you as comfortable as possible.
To avoid lung congestion after surgery, you will be asked to breathe deeply and cough frequently.
To protect your hip during early recovery, a positioning splint, such as a V-shaped pillow placed between your legs, may be used.
Walking and light activity is 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 after surgery. The physical therapist will teach you specific exercises to strengthen your hip and restore movement for walking and other normal daily activities.
The complication rate following hip replacement surgery is low. Serious complications, such as joint infection, occur in fewer than 1% of patients. Major medical complications, such as heart attack or stroke, occur even less frequently.
Occasionally blood clots in the leg veins or pelvis can form as a complication of hip replacement surgery. Your orthopedic surgeon may prescribe one or more measures to prevent blood clots from forming in your leg veins or if they do form, measures to prevent them from becoming symptomatic. These measures may include special support hose, inflatable leg coverings, ankle pump exercises, and blood thinners.
Other complications such as dislocation, nerve and blood vessel injury, bleeding, fracture, and stiffness can occur. In a small number of patients, some pain can continue or new pain can occur after surgery.
Over years, the hip prosthesis may wear out or loosen. This problem will likely be less common with newer materials and techniques. When the prosthesis wears, bone loss may occur because of the small particles produced at the wearing surface. This process is called osteolysis.
The success of your surgery will depend in large measure on how well you follow your orthopedic surgeon’s instructions regarding home care during the first few weeks after surgery.
You will have stitches or staples running along your wound or a suture beneath your skin. The stitches or staples will be removed approximately 2 weeks after surgery.
Avoid getting the wound wet until it has thoroughly sealed and dried. A bandage may be placed over the wound to prevent irritation from clothing or support stockings.
Some loss of appetite is common for several weeks after surgery. A balanced diet, often with an iron supplement, is important to promote proper tissue healing and restore muscle strength. Be sure to drink plenty of fluids.
Exercise is a critical component of home care, particularly during the first few weeks after surgery. You should be able to resume most normal light activities of daily living within 3 to 6 weeks following surgery. Some discomfort with activity and at night is common for several weeks.
Your activity program should include:
- A graduated walking program, initially in your home and later outside
- A walking program to slowly increase your mobility and endurance
- Resuming other normal household activities
- Resuming sitting, standing, and walking up and down stairs
- Specific exercises several times a day to restore movement
- Specific exercises several times a day to strengthen your hip joint
- You may wish to have a physical therapist help you at home
Avoiding Problems After Surgery
Blood Clot Prevention
Follow your orthopedic surgeon’s instructions carefully to minimize the potential risk of blood clots, which can occur during the first several weeks of your recovery.
Warning signs of possible blood clots include:
- Pain in your calf and leg that is unrelated to your incision
- Tenderness or redness of your calf
- Swelling of your thigh, calf, ankle, or foot
Warning signs that a blood clot has traveled to your lung include:
- Shortness of breath
- Chest pain, particularly with breathing
Notify your doctor immediately if you develop any of these signs.
The most common causes of infection following hip replacement surgery are from bacteria that enter the bloodstream during dental procedures, urinary tract infections, or skin infections. These bacteria can lodge around your prosthesis.
Following your surgery, you may need to take antibiotics prior to dental work, including dental cleanings, or any surgical procedure that could allow bacteria to enter your bloodstream. Warning signs of a possible hip replacement infection are:
- Persistent fever (higher than 100°F orally)
- Shaking chills
- Increasing redness, tenderness, or swelling of the hip wound
- Drainage from the hip wound
- Increasing hip pain with both activity and rest
Notify your doctor immediately if you develop any of these signs.
A fall during the first few weeks after surgery can damage your new hip and may result in a need for more surgery. Stairs are a particular hazard until your hip is strong and mobile. You should use a cane, crutches, a walker, or handrails or have someone help you until you improve your balance, flexibility, and strength.
Your orthopedic surgeon and physical therapist will help you decide which assistive aides will be required following surgery, and when those aides can safely be discontinued.
es, joints, ligaments, tendons, muscles, and nerves.
- 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.
- Use a pillow between your legs at night when sleeping until you are advised by your orthopedic surgeon that you can remove it.
Your surgeon and physical therapist will give you more instructions prior to your discharge from the hospital.
You may feel some numbness in the skin around your incision. You also may feel some stiffness, particularly with excessive bending. These differences often diminish with time, and most patients find these are 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 may ask your orthopedic surgeon for a card confirming that you have an artificial hip.
After surgery, make sure you also do the following:
- Participate in a regular light exercise program to maintain proper strength and mobility of your new hip.
- Take special precautions to avoid falls and injuries. Individuals who have undergone hip replacement surgery and experience a fracture may require more surgery.
- Notify your dentist that you have had a hip replacement. You will need to take antibiotics before any dental procedure. Information for your surgeon regarding the use of antibiotics is available from your surgeon.
- See your orthopedic surgeon periodically for routine follow-up examinations and x-rays (radiographs), even if your hip replacement seems to be doing fine.
Your orthopedic surgeon is a medical doctor with extensive training in the diagnosis and nonsurgical and surgical treatment of the musculoskeletal system, including bone.