Anatomy of a Total Hip Replacement

Four primary hip-replacement components include: femoral stem, femoral ball, liner and the acetabular cup.

The Femoral Stem

The Femoral Stem is the main component of a hip replacement. Made of metals such as cobalt chrome or titanium, the stem is inserted into the femur, or thighbone. Your surgeon can choose a cemented or non-cemented prosthesis – both have different advantages for certain patient situations. The stem consists (from the top down) of a taper, neck, and stem.

Your surgeon will choose the optimum femoral stem for you based on criteria such as:

• Clinical data as reported in peer-reviewed medical journals
• Shape, engineering and design, which allow for optimum surgical technique
• “Fit” with the patient’s anatomy
• The choice of a cemented or cementless stem implant, based on the surgeon’s evaluation of the patient’s needs
• The exterior coating of the stem, which contributes to optimum fixation
• The type of surgery – primary, revision, fracture – and the corresponding implant designed for that specific situation
• Confidence int he manufacturer’s reputation, successful clinical history, design, materials and quality

The Femoral Head

The ball, or head, of your implant is a crucial component, replacing the top of the natural thighbone. Heads are typically made of cobalt chrome or ceramic and are produced in varying diameters and neck lengths to fit the patient’s anatomy.

The Acetabular Cup and Liner Systems

The cup replaces the socket of the pelvic bone. The socket is called the acetabulum. During surgery, the natural socket is enlarged to make room for the acetabular cup.

The cup component of the hip replacement works closely in tandem with the liner, typically made of a type of plastic called ultra-high molecular weight polyethylene or special surgical metal alloy. Not all liners are alike, and the liner is vital to longevity of the implant. The best liners will produce the optimum range of motion over the longest span of time.

Cemented Hip vs Cementless Hip Replacement Implants

The precision-engineered shape of the femoral stem implant is crucial to obtaining long-term, pain-free results for the patient. The hip replacement implant is going to become part of the patient’s body, so achieving an optimal fit within the femur is key to a successful outcome. Surgeons refer to this as “fixation.”

There are two ways surgeons can affix the hip implant to the patient’s bone. One way is to use acrylic bone cement, which helps to affix the stem to the femur.

The cementless alternatives sometimes use a porous coating, which helps provide for biological attachment that secures the implant. As an example, three-dimensional beaded coating creates a surface for the patient’s tissue to attach, creating a strong bond with the patient’s own natural tissue and the implant.

Hip Joint Replacement Components

There are two major types of artificial hip replacements: a cemented prosthesis and an uncemented prosthesis. Both are widely used. The choice is usually made by the surgeon based on your age, your lifestyle, and the surgeon’s experience.

Each Prosthesis is made up of two parts:

1) The acetabular shell (socket portion) replaces the acetabulum. The acetabular component is made of a metal shell with a medical grade plastic or metal inner socket liner that acts like a bearing.

2) The femoral component (stem portion) replaces the femoral head. The femoral component is made of metal. The femoral head that attaches to the stem may be a separate part. It is made either of metal or ceramic, although metal is more common.

A cemented prosthesis is held in place by a type of epoxy cement that attaches the metal to the bone.

An uncemented prosthesis has a fine mesh of holes on the surface that allows tissue to grow into the mesh and attach the prosthesis.

Hip Replacement Surgery

The Operation

Accessing the Joint: The steps involved in replacing the hip begin with making an incision on the side of the thigh to allow access to the hip joint. There are several different approaches used to make the incision, usually based on the surgeon’s training and preferences.

Removing the Femoral Head: Once the hip joint is exposed, the femoral head is actually dislocated from the acetabulum (socket) and the femoral head is removed by cutting through the femoral neck.

Reaming the Acetabulum: Attention is then turned toward the socket where, using a power drill and a special reamer, the cartilage is removed from the acetabulum and the bone is formed in a hemispherical shape to exactly fit the metal shell of the acetabular component.

Inserting the Acetabular Component: Once the right size and shape is determined for the acetabulum, the acetabular component is inserted into place. In the uncemented variety of artificial hip replacement, the metal shell is simply held in place by the tightness of the fit or by using screws to hold the metal shell in place. Over the next few weeks, tissue grows into the fine mesh of holes in the metal to attach the implant to the bone. With a cemented prosthesis, a special bone cement is used to anchor the acetabular component to the bone.

Preparing the Femoral Canal: To begin replacing the femur, special rasps are used to shape the hollow femur to the exact shape of the metal stem of the femoral component.

Inserting the Femoral Stem: Once the size and shape are satisfactory, the stem is inserted into the femoral canal. If the femoral component is uncemented, the stem is held in place by the tightness of the fit into the bone (similar to the friction that holds a nail driven into a hole drilled into wooden board, with a slightly smaller diameter than the nail). With a cemented component, the femoral canal is rasped to a size slightly larger than the femoral stem, and the epoxy-type cement is used to bond the metal stem to the bone.

Attaching the Femoral Head: The last step in the procedure before closing the incision is attaching the metal ball that replaces the femoral head.

Closing the Incision

There are several ways that orthopedic surgeons can close the incision after performing an artificial joint replacement. Stainless steel staples are popular with many orthopedic surgeons because they are easy to put in and easy to take out. This can reduce time in the operating room. The stainless steel staples are one of the most inert types of sutures, meaning they have a very low risk of allergic reaction by the patient.

Some surgeons prefer using sutures that dissolve on their own after several weeks. These stitches are normally put in just under the skin. The advantage of this type of closure is that you don’t have to have your stitches taken out! Usually there are special tape closures (sometimes called “butterfly” tapes or “steri- strips”) that are used to hold the edges of the skin closed for the first few days. If you see strips of tape across the incision, this is probably the type of closure that was done. This type of incision closure takes a bit more time in the operating room. There is also a small chance that you may have an allergic reaction to the stitch material that delays the healing of the incision, but this risk is pretty small.

Finally, many surgeons still use the old “tried and true” nylon stitches one at a time. Nylon has withstood the test of time and is nearly as inert as stainless steel. It is strong and holds well until it is removed (somewhere between 10 to 14 days after surgery).

Physical Therapy Treatment Following Hip Replacement Surgery

Once the physical therapist has completed an examination, he/she will put together a treatment plan. The treatment plan lists the types of treatments that will be used for your condition. It gives an indication of how many visits you will need and how long you may need therapy. The plan also lists the goals that you and your therapist think will be the most helpful for getting your activities done safely and with the least amount of soreness. Finally, it will include a prognosis, which is how your therapist feels the treatment will help you improve.

Using Physical Therapy to Ease Pain

Your therapist may choose from one or more of the following tools, or modalities, to help control the symptoms you may have from your hip surgery:

Rest: Rest is an important part of treatment after surgery. If you are having pain with an activity or movement, it should be a signal that there is still irritation going on. You should try to avoid all movements and activities that increase your pain. Be sure to use your crutches as assigned by your doctor, and put only the amount of weight on your leg as approved by your doctor.

Ice: Ice makes the blood vessels in the sore area become narrower, called vasoconstriction. This helps control inflammation that is causing pain and can easily be done as part of a home program. Some ways to put ice on include cold packs, ice bags, or ice massage. Cold packs or ice bags are generally put on the sore area for 10 to 15 minutes.

Heat: Heat makes blood vessels get larger, called vasodilation. This action helps to flush away chemicals that are making your hip hurt. It also helps to bring in nutrients and oxygen, which help the area heal. True heat in the form of a moist hot pack, a heating pad, or warm shower or bath is more beneficial than creams that merely give the feeling of heat. Hot packs are usually placed on the sore area for 15 to 20 minutes. Special care must be taken to make sure your skin doesn’t overheat and burn. It’s also not a good idea to sleep with an electric hot pad at night.

Electrical Stimulation: This treatment stimulates nerves by sending an electrical current gently through your skin. In the acute treatment after meniscal surgery, the stimulation can ease pain and help remove swelling. It is often used in combination with ice in the early stages and heat in the later stages of recovery. This treatment stimulates nerves by sending an electrical current gently through your skin. Some people say it feels like a massage on their skin. Electrical stimulation can ease pain by sending impulses that are felt instead of pain. Once the pain eases, muscles that are in spasm begin to relax, letting you move and exercise with less discomfort.

Improving Range of Motion: To improve your ROM, your therapist can use graded joint mobilization, manual stretching and select exercises. Active movement and stretching as part of a home program can also help restore movement.

Gait Training: Once you are safe to put full weight through your operated leg, your therapist will work with you to “fine tune” your gait. Retraining may be needed if you’ve developed a limp, which may be due to apprehension of pain or simply from a habit you’ve developed since your injury or surgery. Getting a normal walking pattern starts with shifting your weight when you walk. If you can visualize the way competitive speed skaters sway their hips when they skate, you’ll get the picture of what it means to shift your weight. When you place your sore-side foot down and prepare to step through with the opposite foot, you may be hesitant to shift the weight of your hip over your planted foot. This leads to an antalic gait; better known as a limp. Practicing this part of the walking cycle may be all that is needed to help you “remember” how to walk without a limp. Your therapist will also make sure that your steps are equal in width and length.

Exercise

Aquatic Therapy: By doing exercise in a pool, the properties of buoyancy and warmth to let you exercise with ease of movement. The buoyancy of the pool can be used to make exercise easier, to give resistance with some of the exercise, and to help you begin walking with less stress on your new hip. The warmth can help muscles relax, improve circulation, and ease soreness letting you move more easily. If your therapist works with you in the pool, only a few visits are usually necessary before you get into a regular program on land. If you are getting good benefits in the pool, you will probably want to get a membership to the pool so your other visits can be used to work on strengthening, walking, and getting you back to doing the activities you enjoy.

Strengthening: After a hip surgery, you can expect that your leg muscles will be weak. When muscles weaken from pain or disuse, other muscles overpower the weaker ones. This leads to an imbalance where the weaker muscles become longer and the stronger muscles become shorter. These imbalances change the way the joints usually work. The swelling and pain from your hip pain and surgery can lead to weakened muscles around the hip and knee. The quadriceps muscle usually is affected. Exercises can be chosen to help regain the strength in the muscles around the hip.

Biofeedback: Muscle control is the basis for strength. Using biofeedback can help you get back the control of the quadriceps muscle. The biofeedback unit has surface electrodes that are put on the skin over the muscle that needs help. As you practice working the muscle, the machine will give you “feedback” to let you see and hear how the weak muscle is performing. The biofeedback unit can also be set to alert you if other muscles are overpowering the weak muscle. Biofeedback can be used while you do your exercise program so you’ll know if you’re actually working the right muscle.

Functional Electrical Stimulation (FES): This is a way to use electrical stimulation to help retrain a weakened or deconditioned muscle. Electrodes are placed over the muscle that is to be retrained. The electrical current passes through the skin and stimulates the motor nerve of the muscle causing it to tighten for a set time without your conscious effort. The machine is usually set to go on for about 10 to 15 seconds and then off for 15 to 30 seconds. Once you get the idea of how the muscle feels when it tightens, you can begin tightening the muscle when the current comes on again. After you get a good contraction going, you should be able to successfully tighten the muscle without the use of the current.

Progressive Resistive Exercises (PREs): Many choices of PREs are now used in rehabilitation. Some of these choices include pulley systems, free weights, rubber tubing, manual resistance, and computerized exercise devices. Using PREs is a way to apply graded resistance to muscle groups to gradually help them gain endurance and strength. These exercises typically start with lighter weights with lots of repetitions, and as endurance increases, more weight is gradually used with fewer repetitions.

Exercise Precautions First, avoid “overdoing” it. If you find that you are getting swelling late in the day, it may be a sign you may doing too much too quickly. Second, avoid pain. Pain is an indicator that something isn’t right. You may feel some discomfort with your exercises, but this should be “reasonable” discomfort. If pain is excessive or lasts more than one hour after exercise, inform your therapist at your next visit. You may need to change the number of repetitions, the amount of pressure, or the how often you are doing the exercises.

Progressive Exercise: Exercises will be given to help improve motion, strength, and endurance in the hip muscles. Your program will also address key muscle groups of the buttocks, thigh, and calf. Other exercises can be used to simulate day-to-day activities like stair climbing, pivoting, and squatting, depending on which phase you have completed. Following are some types of exercises that may be used to help your condition.

Proprioceptive Exercises: These are exercises that help retrain your position sense, also called “joint sense”. If you close your eyes and hold up your hand, you know what your hand is doing, even though you don’t “see” it. We get position sense by way of our vision, middle ear balance, and from tiny receptors in the ligaments and joints. When we close our eyes, we rely on middle ear balance and these special receptors to keep us upright. If there has been swelling or injury in or around a joint, these tiny receptors get injured and do not recover. You can do certain exercises to get the other receptors to do more, regaining what was lost with the damaged receptors. The loss of position sense puts the joint at further risk of injury because the joint loses stability, like having loose lug nuts on a wheel of a car. Special exercises, called proprioceptive or neuromuscular exercises, help protect the hip by “tightening the lug nuts.” You can think of these exercises like balance training. Examples include balancing on one leg with your eyes open/closed, walking on uneven or soft surfaces, or practicing on a special balance board. Some therapists use special manual exercises to get the other receptors working better.

Closed Kinetic Chain (CKC) Exercises: These are exercises in which the foot is kept on the ground while movement and resistance take place in the joints and muscles above. These types of exercises are important because they are so much like the activities we do every day. For example, a partial squat exercise is the same action as lowering yourself onto a chair or couch. A leg press is a lot like the action of going up a stair or step. These exercises add strength and stability around the muscles and joints of the hip and leg.

Stabilization Exercises: Muscles that are closer into the “core” of the body act as stabilizers. The job of these stabilizers is to put your joints in the right position and to steady them while you squat, walk, or jump. These muscles form a stable platform, letting you move your leg and foot with precision. If these muscles aren’t doing their job, your hip loses some of its control, keeping it from working its best. The stabilization exercises you’ll be working on can be thought of in the way you take care of the tires on your car. If you had a wear spot on one of your newer tires, you’d be pretty upset with a tire dealer who simply wanted to replace it. You would first want to be sure the car was checked for alignment, that the wheels were balanced, and that the lug nuts were tightened. Otherwise, your new tire would end up getting worn like the last one. Treating your new hip takes more than just pain control (new tire). It requires training the stabilizers to assist with posture (alignment) and to guide the joint in the right placement (lug nuts) while you go about your daily tasks.

Home Program: As your condition keeps getting better, you will be given advanced exercises to do at home, a pool, or in a gym setting. You may be scheduled to recheck with your therapist at regular intervals to make sure you are doing these exercises routinely and safely. During these rechecks, you may be given additional exercises to work on over the next few weeks. Eventually, you will be progressed to a final home program. Once you’ve been released to full activity, you may be instructed to follow up with a few visits over the next few months. This will give a comparison of strength and function of the operated hip and to make sure you are performing at peak levels. Before you are completely done with therapy, more measurements will be taken to see how well you’re doing now compared to when you first started in therapy.

Why is Hip Revision Surgery Needed?

The most common reasons for revision hip surgery are:

Mechanical Loosening

Mechanical loosening means that the attachment between the artificial joint and the bone has become loose. There are many reasons premature loosening can occur, such as those discussed below. Mechanical loosening can occur in both cemented and cementless artificial joints.

Infection

If an artificial hip joint becomes infected, it will usually become stiff and painful and begin to detach from the bone. An infected artificial hip joint will usually have to be replaced to cure the infection. It may be exchanged for a new artificial hip joint during the same operation. Antibiotics may be administered for several weeks or months after the exchange operation.

Fractures

A fracture near an artificial hip joint that must be fixed surgically, may require replacement with a new hip implant. For example, if the thighbone (femur) breaks below the stem of an artificial hip, a new component with a longer stem may be implanted to hold the fracture together while it heals.

Instability

Instability means that the joint dislocates, which is very painful. This is much more common in the hip, where the metal ball can slip out of the artificial socket. If dislocation occurs contact your surgeon immediately. If dislocation happens more than once, your surgeon may recommend the artificial hip joint be replaced.

Wear

As a result of normal use, the metal, plastic or ceramic components used in the hip implant may begin to wear away. If the wear is discovered early the revision may only require replacing the worn-out component. If the wear continues until metal is rubbing on metal, the whole joint may need to be replaced.

Breakage

Finally, the metal may break due to the constant stress the artificial hip joint undergoes everyday. In weight bearing joints, such as the hip, this is greatly affected by weight and activity level.

Recovery and Rehabilitation

Checking on My Hip Replacement

Being aware of the signs of hip implant complications will help you to know when to seek medical help.

Your hip implant may have complications because the:

• Hip joint is moved the wrong way
• Joint surface wears away
• Bone wears away
• Implant becomes loose
• Replacement parts break or fracture
• The cement is used to fix the hip cracks or loosens

Implant complications may include one or more of the following signs:

• New or recurrent pain in the groin, hip, buttock or thigh
• Pain with walking
• Pain with rising from a sitting position
• Weakness in the leg
• Decreased movement of the hip joint
• Decreased ability to stand on the leg
• Redness and/or tenderness over the joint
• Gradual or sudden shortening of the leg

Contact your surgeon right away if you believe you are having complications with your hip implant.

Your surgeon will examine your hip and your leg. You will probably be asked to have an x-ray or scan of the joint. Your surgeon will decide what is causing the complications and talk to you about treatment options.

Physical Therapy Evaluation Following Hip Replacement Surgery

Activity Immediately Following Surgery

There are different ways to surgically reconstruct hips, so the instructions you will follow after surgery will depend on your doctor and the way the surgery was done.

Precautions: Follow your doctor’s instructions regarding the amount of weight you can put through your operated hip.

Avoid activities that put a strain on the surgical area. During your activities, let pain guide your decisions. If you feel pain with any activity, stop or alter what you are doing because pain at this stage is an indicator of strain or irritation.

Exercises: Any exercises you do should be done only at the direction of your doctor or therapist. The choices of exercise used after surgery will depend upon the type of procedure used. You may be given a few exercises that you can do for your knee, ankle, and foot. Gently bending and straightening your ankle can keep your calf muscle flexible while “pumping” away excess swelling. Some exercises are used to help control pain and help with movement in the knee and hip. Low-grade exercises for the thigh muscles can usually begin right away. Extra pain felt after these or other exercises will indicate whether you are overdoing it. You may need to change the number of repetitions, the amount of pressure, or the how often you are doing the exercises.

Inpatient Physical Therapy During Your Hospital Stay

Your physical therapist may schedule to see you in the hospital on the same or next day after surgery. The first visit gives your physical therapist an idea of how well your hip is moving and how well you remember and are practicing your hip precautions. It is also a time to see how well you can move while in your hospital bed, your safety when getting up and sitting on the edge of the bed, and whether you can begin to walk using a walking aid and putting the right amount of weight through your foot. As you gain more confidence and endurance with walking, your therapist will begin to train you how to go up and down stairs using your walking aid.

You may also begin doing a few exercises in your hospital room the first visit. You could begin a series of strengthening exercises for the thigh and leg muscles. As your condition improves, you may be transported by wheelchair to the physical therapy gym for your treatment sessions.

While you are in the hospital, your therapist may see you for therapy up to two times each day. You can expect to stay in the hospital at least three to four days after surgery.

You may be released to go home when you can use your hip precautions with all activities. Your therapist will check to see that you can get in and out of bed safely, walk with the right amount of weight on your hip using a walking aid, go up and down stairs safely, and do your exercises by yourself.

After you Leave The Hospital

Once discharged from the hospital, you may be seen in the home for treatment. This is to make sure you are safe in and around your home. You could be seen for at least one home visit for the safety check and to review your exercise program.

Outpatient Physical Therapy

On your first outpatient visit, your physical therapist will want to gather some more information about the history of your condition. You may be given a questionnaire that helps you describe day-to-day problems you are having because of your condition. The information you give will help measure the success of your treatment. You may also be asked to rate your pain on a scale of one to ten. This will help your therapist gauge how much pain you have now and how your pain and symptoms change once you’ve had treatment. Your therapist will probably ask some more questions about your condition to get an idea how your hip has been feeling since your surgery:

How is your hip feeling since the surgery?

Where do you feel your pain now?

Are you getting any more swelling?

Physical Therapy Evaluation

Once all this information has been gathered, your condition will be evaluated. The main parts of the evaluation are listed below and may be done in the order chosen by your therapist.

Posture/Observation: our physical therapist will check your overall posture, including the alignment of your low back, pelvis, and your knees and ankles. These have a significant role in the health of your hip. Your therapist will also check the surgical area to make sure the incisions are healing. By comparing each side, your therapist can determine if there is extra swelling, bruising, or a loss in the size of your muscles.

Gait Analysis: By watching you walk back and forth; your therapist can make sure your walking aid is adjusted for you and that you are using it safely. The amount of weight you put through your leg will depend on your doctor and the type of procedure done (cemented or not).

Range of Motion (ROM): Your therapist will check the ROM in your hip. This is a measurement of how far you can move your hip in different directions. Measurements could include forward and back (flexion/extension), side-to-side (abduction/adductions), and rotating (internal or external rotations). Movement will be limited to the precautions depending on whether you had a posterior or anterior surgical approach. Your ROM is written down to compare how much improvement you are making with the treatments.

Strength: Your therapist will test the strength of your muscles. You could be asked to hold against resistance as your therapist tests the muscles around the hip and knee. Other muscles that may be checked include the buttocks and calf muscles. These measurements are compared to your other side. Weakness in key muscles will be addressed with a strengthening program.

Girth: Using a tape measure, your therapist may compare the circumference of your thigh, knee and calf. This can give an indication of swelling or whether your muscles have lost size (atrophied) from a lack of use or from having pain.

Manual Examination: You may be given a manual examination of the hip. Your therapist will carefully move your leg in different positions to make sure that the hip and other joints are moving smoothly. Your therapist will also look at the flexibility of the muscles and tendons around your hip. This type of exam can help guide your therapist to know which type of treatments will help you the most.

Palpation: Palpation is when your therapist feels the soft tissues around the sore area. This is done to check the skin for changes in temperature, to see how much swelling you have, to pinpoint areas of soreness, and to see if there are tender points or spasm in the muscles around the hip joints. This can help your therapist get a good idea about which treatments will help you the most.

Potential Complications Following Hip Replacement Surgery

As with all major surgical procedures, complications can occur. Some of the most common complications following hip replacement are:

• Thrombophlebetis
• Infection
• Dislocation
• Loosening
• Myositis Ossificans

This is not intended to be a complete list of the possible complications, but it includes the most common problems.

Thrombophlebitis

Thrombophlebitis, sometimes called Deep Venous Thrombosis (DVT), can occur after any operation, but is more likely to occur following surgery on the hip, pelvis, or knee. DVT occurs when the blood in the large veins of the leg forms blood clots within the veins. This may cause the leg to swell, become warm to the touch and painful. If the blood clots in the veins break apart, they can travel to the lung, where they get lodged in the capillaries of the lung and cut off the blood supply to a portion of the lung. This is called a pulmonary embolism. (Pulmonary = lung, embolism = fragment of something traveling through the vascular system). Most surgeons take preventing DVT very seriously. There are many ways to reduce the risk of DVT, but probably the most effective is getting you moving as soon as possible!

Some of the commonly used preventative measures include:

• Pressure stockings to keep the blood in the legs moving
• Medications that thin the blood in the legs moving

Infection

Infection can be a very serious complication following an artificial joint surgery. The chance of getting an infection following total hip replacement is approximately 1%. Some infections may show up very early – before you leave the hospital. Others may not become apparent for months, or even years, after the operation. Infection can spread into the artificial joint from other infected areas. Your surgeon may want to make sure that you take antibiotics when you have dental work, or surgical procedures on your bladder and colon, to reduce the risk of spreading germs to the joint.

Dislocation

Just like your natural hip, an artificial hip can dislocate (where the ball comes out of the socket).

There is a greater risk just after surgery, before the tissues have healed around the new joint, but there is always a risk. The therapist will instruct you very carefully how to avoid activities and positions, which may cause a hip dislocation. A hip that dislocates more than once may have to be revised (which means another operation) to make it more stable.

Loosening

The major reason that artificial joints eventually fail continues to be a process of loosening where the metal or cement meets the bone. There have been great advances in extending how long an artificial joint will last, but all will eventually loosen and require a revision. A loose hip is a problem because it causes pain. Once the pain becomes unbearable, another operation will probably be required to revise the hip.

Myositis Ossificans

Myositis ossificans is a curious problem that can affect the hip after both a primary hip replacement and a revision hip replacement. The condition occurs when the soft tissue around the hip joint begins to develop calcium deposits. “Myositis” means inflammation of muscle and “ossificans” refers to the process of ossification or the formation of bone. This can lead to a situation where the bone actually can form completely around the hip joint. This leads to stiffness in the hip resulting in much less motion in the hip joint than normal. It also causes pain in the hip joint.

Myositis ossificans is more common in people who have a long history of osteoarthritis with multiple bone spurs. Something about the genetic makeup in these people make them more likely to produce bone tissue. Major reconstruction operations, such as revision surgery, seem to do more damage to the surrounding tissues than primary hip replacements. The operation is simply longer and harder to do. This also seems to make it more likely that calcium deposits will form.

The treatment for myositis ossificans may actually begin before you get it. In cases where your surgeon feels that you are at high risk for developing the condition, he may recommend medications such as Indomethacin? be taken following surgery. This medication reduces the tendency for bone to form and may protect you from developing myositis ossificans.

A much more effective method that has been used a great deal is to prevent the development of myositis ossificans using radiation treatments immediately after surgery. These are the same type of radiation treatments used to treat cancer. Several short radiation treatments, begun the day after surgery and continued for 3-5 days, seem to drastically reduce the risk of developing myositis ossificans. If myositis ossificans forms anyway, treatment will depend on how much it affects your hip, how much pain it causes, and how much it restricts motion. In some severe cases, you may choose to have a second operation to remove the calcified tissue that has formed. This is usually followed by radiation treatments to prevent the calcium deposits from returning.

Understanding Blood Clot Prevention (Deep Vein Thrombosis)

Blood clots that form inside the veins of the legs, called Deep Venous Thrombosis (DVT), are a common problem following many types of surgical procedures. It is true that these blood clots can also form in certain individuals who have not undergone any recent surgery. These blood clots form in the large veins of the calf and may continue to grow and extend up into the veins of the thigh, and in some cases into the veins of the pelvis.

The risk of developing DVT is much higher following surgery involving the pelvis and the lower extremities. There are many reasons that the risk of DVT is higher after surgery. The body is trying to stop the bleeding associated with surgery and the body’s clotting mechanism is very hyperactive during this period. Injury to blood vessels around the surgical site from normal tugging and pulling during surgery, can set off the clotting process. Finally, blood that doesn’t move well sits in the veins and becomes stagnant. Blood that sits too long in one spot usually begins to clot.

Why do we worry about blood clots? Blood clots that fill the deep veins of the legs stop the normal flow of venous blood from the legs back to the heart. This causes swelling and pain in the affected leg. If the blood clot inside the vein does not dissolve, the swelling may become chronic and can cause permanent discomfort and swelling. While this may seem bad enough, the real danger that a blood clot poses is much more serious. If a portion of the forming blood clot breaks free inside the veins of the leg, it may travel through the veins to the lung where it can lodge itself in the tiny vessels of the lung. This cuts off the blood supply to the portion of the lung that is blocked. The portion of the lung that is blocked cannot survive and may collapse, which is called a pulmonary embolism. If a pulmonary embolism is large enough and the portion of the lung that collapses is large enough it may cause death. With this in mind, it is easy to see why prevention of DVT is a serious matter. Reducing the risk of developing DVT is a high priority following any type of surgery. Things that can be done to reduce the risk of developing DVT fall into two categories:

• Mechanical – getting the blood moving better
• Medical – using drugs to slow the clotting process

Mechanical

Blood that is moving is less likely to clot. Getting YOU moving so that your blood is circulating is perhaps the most effective treatment against developing DVT. While you are in bed, there are other things that can be done to increase the circulation of blood from the legs back to the heart. Simply pumping your feet up and down (like pushing on the gas pedal) contracts the muscles of the calf, squeezes the veins in the calf, and pushes the blood back to the heart. You can’t do this too much!

Pulsatile stockings do the same thing. These special stockings that wrap around the calf and thigh are inflated by a pump every few minutes, squeezing the veins in the calf and thigh pushing the blood back to the heart. Support hose are still commonly used following surgery. These hose work by squeezing the veins of the leg shut. This reduces the amount of stagnant blood that is pooling in the veins of the leg and reduces the risk of that blood clotting in the veins. Finally, getting you out of bed and walking will result in muscle contraction of the legs and keep the blood in the veins of the leg moving.

Medical

Drugs, which slow down the body’s clotting mechanism, are widely used following surgery of the hip and knee to reduce the risk of DVT. These drugs include aspirin in very low risk situations and heparin shots twice a day in moderately risky situations. For conditions that have a high risk for developing DVT, several very potent drugs are available that can slow the clotting mechanism very effectively.

In most cases of hip and knee surgery, both mechanical and medical measures are used at the same time. It has become the norm to use pulsatile stockings immediately after surgery, have you begin exercises immediately after surgery, get you out of bed as soon as possible and place you on medication to slow the blood-clotting mechanism.

Understanding Hip Dislocation Precautions

Your new artificial hip has a limited range of safe motion while it is healing. For about three months, you will need to follow special safety rules called “hip precautions” to protect your new hip while it heals. While you are in the hospital, your healthcare team will remind you often about the need to follow the hip precautions. Once you get home, you will have to remember to follow these rules until your surgeon approves motion beyond that described in these hip precautions.

Don’t bend the hip past 90 degrees. This means don’t raise your leg in bed.

Whether sitting or lying down, keep the angle made by the leg and upper body below 90 degrees!

Don’t bend too far when standing

Don’t allow the knee of your operated leg to cross the midline of your body. This means don’t let your knee move across your body past your navel (belly button). This precaution is especially important when lying on your side or trying to turn in bed. When lying on the unaffected side, place pillows between your legs to keep your hip in the correct position. When sitting, do not cross your affected leg.

Don’t turn the foot of your operated leg inward. This means when lying on your back, don’t roll your affected leg toward the other leg as you might do when rolling over. Also, don’t stand pigeon-toed. Keep the toes of your affected leg pointed forward when you stand, sit or walk.

What if Your Hip Dislocates?

Dislocation of an artificial hip is uncommon, and occurs within the first three months after surgery. The problem usually starts with a popping sensation or a slipping sensation. You will be unable to bear weight on the affected limb and may experience a fair amount of discomfort. You will need to contact your orthopedic surgeon immediately and probably have someone take you to the emergency room. Putting the hip back in the socket will probably require medication given by I.V. to relax the muscles and allow your surgeon to put the hip back into place.

What Activities Can I Participate in After I Recover?

After undergoing an artificial hip replacement, you need to have realistic expectations about what type of activities you can participate in. There are different risks associated with different types of activities. Some activities can lead to damage of the joint over time due to wear and tear of the joint. In general, the more vigorous the activity, the higher risk of damaging the implant, increasing the wear and tear on the implant or increasing the risk of loosening of the implant.

Activities that cause high impact stresses on the implant should be avoided. These types of activities include competitive racquet sports such as tennis, squash and racquetball. High impact aerobics and jogging should also be avoided. Lower stress activities such as golf, hiking, walking, biking, and swimming are excellent forms of exercise for patients with an artificial hip replacement.

Some activities are dangerous because they have a high risk of injuring you. For example, rough contact sports such as football, soccer, motor cross, basketball and volleyball are dangerous because the joint may be injured. Falling or getting tangled with opponents can result in either a dislocation of the joint itself, or a fracture of the bone around the implant. These activities should be avoided. Remember, if you have questions about your activities, ask your doctor.