Minimally Invasive Total Knee ReplacementArthritis and Knee Replacement
Symptoms
Treatment Options
Minimally Invasive Knee Replacement
Research on the Horizon Total knee replacement (knee arthroplasty) is a surgery that is performed for severe degenerative disease of the knee joint. More than 542,000 people undergo the procedure each year.
Minimally invasive total knee replacement involves the use of a smaller incision than the one used in traditional knee replacement. In the traditional method, the incision averages 8 to 10 inches in length. In minimally invasive knee surgery, the incision is only 4 to 6 inches long. Because there is less damage to the tissue around the knee, patients who undergo this procedure may expect a shorter hospital stay, a shorter recovery, and a better looking scar.
Arthritis and Knee ReplacementKnee replacement is the resurfacing of the worn out surfaces of the knee and replacing the lost cartilage and diseased bone with metal and plastic. Knees wear out for a variety of reasons, including inflammation from arthritis, injury, or simple wear and tear.
Arthritis can run in families. Most knee arthritis is due to a lifetime of wear and tear. Nobody knows why some people get severe arthritis, while others don't, or why arthritis can occur in one knee and not the other. Previous injury and obesity are some known causes of arthritis.
SymptomsKnee arthritis leads to pain, which often happens with activity. The knee can also hurt at rest. Patients often find it difficult to climb or go down stairs, walk distances, or get up from low seats. Patients may also have swelling about the knee, stiffness, or a feeling of looseness.
Treatment Options Nonsurgical Treatment
The first steps in treating knee arthritis are activity modification, regular exercise, and weight loss. The muscles around the knee protect it during activity. With every step, forces equal to several times a person's body weight are transmitted through the knee. Therefore, improved strength and decreased body weight can prolong the life of the knee.
Soft knee braces and shoe modifications can sometimes help. Pain relievers and anti-inflammatory medications are also recommended. Some dietary supplements might also help. A cane or walker can also be tried to assist with walking and to improve mobility.
Steroid injections directly into the knee can be used to decrease inflammation. A lubricant may be used to improve the function of the knee. These can offer some relief. They can be repeated from time to time if they help.
Surgical Treatment
Knee replacement is recommended for knee arthritis if nonsurgical treatments have failed and the pain is limiting lifestyle and activities. Surgical options include knee arthroscopy (although this is rarely used just for arthritis), partial knee replacement, and total knee replacement.
The goal of knee replacement is to provide a pain-free knee that allows relatively normal activities and lasts for a long time. To achieve these goals, it is important that the knee implants be inserted with proper positioning. The bones and ligaments are prepared very carefully to allow the knee to be functional and durable. Using the current techniques, 90% to 95% of knee replacements last 15 years or longer.
Minimally Invasive Knee ReplacementMinimally invasive knee replacement accomplishes everything that a traditional knee replacement does, but through a smaller incision (4- to 6-inch incision compared with an 8- to 10-inch incision). With the smaller incision come the potential benefits of a shorter hospital stay, shorter recovery, and a better looking scar.
Although there is no question that an artificial knee can be implanted through a smaller incision, doctors still don't know whether it can be done as well as with the traditional approach.
New techniques for opening the knee may be more important than the length of the incision. Some techniques are "quadriceps-sparing" because they protect the quadriceps tendon and muscle in the front of the thigh. Other techniques called "mid-vastus" and "sub-vastus" make small incisions in the muscle but are also less invasive.
Outcomes
Several early studies of minimally invasive knee replacement surgery have shown some benefits compared with traditional knee replacement, such as less blood loss, shorter hospital stay, and better motion. Other studies have shown a higher rate of complications with minimally invasive knee surgery, including poorer positioning of the knee implants.
Research on the Horizon. More research is needed on the long-term function and durability of minimally invasive knee replacements.
Advocates of minimally invasive knee replacement are working to address concerns about accurate positioning of the knee implants.
Surgeons are also combining the small incision with computer-guided instruments to help improve outcomes. However, the potential benefits, risks, and costs of this have not yet been established.
Sunday, October 24, 2010
Post-op hip activities
Dos and Don'tsDos and don'ts (precautions) vary depending on the orthopaedic surgeon's approach. Your doctor and physical therapist will provide you with a list of dos and don'ts to remember with your new hip. These precautions will help to prevent the new joint from dislocating and to ensure proper healing. Here are some of the most common precautions:
The Don'ts
•Don't cross your legs at the knees for at least 8 weeks.
•Don't bring your knee up higher than your hip.
•Don't lean forward while sitting or as you sit down.
•Don't try to pick up something on the floor while you are sitting.
•Don't turn your feet excessively inward or outward when you bend down.
•Don't reach down to pull up blankets when lying in bed.
•Don't bend at the waist beyond 90°.
•Don't stand pigeon-toed.
•Don't kneel on the knee on the unoperated leg (the good side).
•Don't use pain as a guide for what you may or may not do.
The Dos
•Do keep the leg facing forward.
•Do keep the affected leg in front as you sit or stand.
•Do use a high kitchen or barstool in the kitchen.
•Do kneel on the knee on the operated leg (the bad side).
•Do use ice to reduce pain and swelling, but remember that ice will diminish sensation. Don't apply ice directly to the skin; use an ice pack or wrap it in a damp towel.
•Do apply heat before exercising to assist with range of motion. Use a heating pad or hot, damp towel for 15 to 20 minutes.
•Do cut back on your exercises if your muscles begin to ache, but don't stop doing them!
The Don'ts
•Don't cross your legs at the knees for at least 8 weeks.
•Don't bring your knee up higher than your hip.
•Don't lean forward while sitting or as you sit down.
•Don't try to pick up something on the floor while you are sitting.
•Don't turn your feet excessively inward or outward when you bend down.
•Don't reach down to pull up blankets when lying in bed.
•Don't bend at the waist beyond 90°.
•Don't stand pigeon-toed.
•Don't kneel on the knee on the unoperated leg (the good side).
•Don't use pain as a guide for what you may or may not do.
The Dos
•Do keep the leg facing forward.
•Do keep the affected leg in front as you sit or stand.
•Do use a high kitchen or barstool in the kitchen.
•Do kneel on the knee on the operated leg (the bad side).
•Do use ice to reduce pain and swelling, but remember that ice will diminish sensation. Don't apply ice directly to the skin; use an ice pack or wrap it in a damp towel.
•Do apply heat before exercising to assist with range of motion. Use a heating pad or hot, damp towel for 15 to 20 minutes.
•Do cut back on your exercises if your muscles begin to ache, but don't stop doing them!
Hip Implants
Hip ImplantsImplant Design
Implant Construction
Implant Insertion
Cemented Total Hip Replacement
Cementless Total Hip Replacement
Hybrid Total Hip Replacement
Partial Hip Replacements
Hip Resurfacing
Longevity and Outcomes Total hip joint replacement is an orthopaedic success story, enabling hundreds of thousands of people to live fuller, more active lives.
Using metal alloys, high-grade plastics, and polymeric materials, orthopaedic surgeons can replace a painful, dysfunctional joint with a highly functional, long-lasting prosthesis.
Over the past half-century, there have been many advances in the design, construction, and implantation of artificial hip joints, resulting in a high percentage of successful long-term outcomes.
Implant DesignThe hip joint is called a ball-and-socket joint because the spherical head of the thighbone (femur) moves inside the cup-shaped hollow socket (acetabulum) of the pelvis.
To duplicate this action, a total hip replacement implant has three parts: the stem, which fits into the femur; the ball, which replaces the spherical head of the femur; and the cup, which replaces the worn out hip socket. Each part comes in various sizes to accommodate various body sizes and types.
In some designs, the stem and ball are one piece; other designs are modular, allowing for additional customization in fit.
Several manufacturers make hip implants. The brand used by your doctor or hospital depends on many factors, including your needs (based on your age, weight, bone quality, activity level, and health), the doctor's experience and familiarity with the device, and the cost and performance record of the implant. These are issues you may wish to discuss with your doctor.
Implant ConstructionMany people credit Sir John Charnley, a British orthopaedist, with performing the first modern total hip replacement. His innovations included combining a metal stem and ball with a plastic shell and using a methacrylate cement to hold the devices in place.
Today, the stem portions of most hip implants are made of titanium- or cobalt/chromium-based alloys. They come in different shapes and some have porous surfaces to allow for bone ingrowth.
Cobalt/chromium-based alloys or ceramic materials (aluminum oxide or zirconium oxide) are used in making the ball portions, which are polished smooth to allow easy rotation within the prosthetic socket.
The acetabular socket can be made of metal, ultra-high molecular-weight polyethylene, or a combination of polyethylene backed by metal.
All together, these components weigh between 14 and 18 ounces, depending on the size needed.
All the materials used in a total hip replacement have four characteristics in common:
•They are biocompatible. They can function in the body without creating either a local or a systemic rejection response.
•They are resistant to corrosion, degradation, and wear. Therefore, they will retain their strength and shape for a long time. Resistance to wear is particularly significant in maintaining proper joint function and preventing the further destruction of bone caused by particulate debris generated as the implant parts move against each other.
•They have mechanical properties that duplicate the structures they are intended to replace. For example, they are strong enough to withstand weight-bearing loads, flexible enough to bear stress without breaking, and able to move smoothly against each other as required.
•They meet the highest standards. These high standards extend to fabrication and quality control at a reasonable cost.
Top of page
Implant InsertionDuring a total hip replacement surgery, the orthopaedic surgeon will take a number of measurements to ensure proper prosthesis selection, limb length, and hip rotation. After making the incision, the surgeon works between the large hip muscles to gain access to the joint.
The femur is pushed out of the socket, exposing the joint cavity. The deteriorated femoral head is removed.
The acetabulum is prepared by cleaning and enlarging it with circular reamers of gradually increasing size. The new acetabular shell is implanted securely within the prepared hemispherical socket. The plastic inner portion of the implant is placed within the metal shell and fixed into place.
Next, the femur is prepared to receive the stem. The hollow center portion of the bone is cleaned and enlarged, creating a cavity that matches the shape of the implant stem. The top end of the femur is planed and smoothed so the stem can be inserted flush with the bone surface. If the ball is a separate piece, the proper size is selected and attached. Finally, the ball is seated within the cup so the joint is properly aligned and the incision is closed.
Hip replacements may be cemented, cementless, or hybrid (a combination of cemented and cementless components), depending on the type of fixation used to hold the implant in place. Although there are certain general guidelines, your surgeon will evaluate your particular situation carefully before making any decisions. Do not hesitate to ask which type of implant will be used in your situation and why that choice is appropriate for you.
Cemented Total Hip ReplacementOver the past 40 years, there have been many improvements in both the materials and the methods used to hold the femoral and acetabular components in place. Today, the most commonly used bone cement is an acrylic polymer called polymethylmethacrylate (PMMA).
A patient with a cemented total hip replacement can put full weight on the limb and walk without support almost immediately after surgery, resulting in a faster rehabilitation. Although cemented implants have a long and distinguished track record of success, they are not ideal for everyone.
Cemented fixation relies on a stable interface between the prosthesis and the cement and a solid mechanical bond between the cement and the bone. Today's metal alloy stems rarely break, but they can occasionally loosen. Two processes, one mechanical and one biological, can contribute to loosening.
•In the femoral component, cracks (fatigue fractures) in the cement that occur over time can cause the prosthetic stem to loosen and become unstable. This occurs more often with patients who are very active or very heavy. The action of the metal ball against the polyethylene cup of the acetabular component creates polyethylene wear debris. The cement or polyethylene debris particles generated can then trigger a biologic response that further contributes to loosening of the implant and sometime to loss of bone around the implant.
•The microscopic debris particles are absorbed by cells around the joint and initiate an inflammatory response from the body, which tries to remove them. This inflammatory response can also cause cells to remove bits of bone around the implant, a condition called osteolysis. As the bone weakens, the instability increases. Bone loss can occur around both the acetabulum and the femur, progressing from the edges of the implant.
Despite these recognized failure mechanisms, the bond between cement and bone is generally very durable and reliable. Cemented total hip replacement is more commonly recommended for older patients, for patients with conditions such as rheumatoid arthritis, and for younger patients with compromised health or poor bone quality and density. These patients are less likely to put stresses on the cement that could lead to fatigue fractures.
Cementless Total Hip ReplacementIn the 1980s, new implant designs were introduced to attach directly to bone without the use of cement. In general, these designs are larger and longer than those used with cement.
They also have a surface topography that is conducive to attracting new bone growth. Most are textured or have a surface coating around much of the implant so that the new bone actually grows into the surface of the implant. Because they depend on new bone growth for stability, cementless implants require a longer healing time than cemented replacements.
The orthopaedic surgeon must be very precise in preparing the femur for a cementless impact. The implant channel must match the shape of the implant itself very closely. New bone growth cannot bridge gaps larger than 1 mm to 2 mm.
Your surgeon may recommend a period of protected weight-bearing (using crutches or a walker) to give the bone time to attach itself to the implant. This protected weight bearing helps to ensure there is no movement between the implant and bone so a durable connection can be established.
Cementless femoral components tend to be much larger at the top, with more of a wedge shape. This design enables the strong surface (cortex) of the bone and the dense, hard spongy (cancellous) bone just below it to provide support.
The acetabular component of a cementless total hip replacement also has a coated or textured surface to encourage bone growth into the surface. Depending on the design, these components may also use screws through the cup or spikes, pegs, or fins around the rim to help hold the implant in place until the new bone forms. Usually these components have a metal outer shell and a polyethylene liner.
The pelvis is prepared for a cementless acetabular component using a process similar to that used in a cemented total hip replacement procedure. The intimate contact between the component and bone is crucial to permit bone ingrowth.
Initially, it was hoped that cementless total hip replacement would eliminate the problem of bone resorption or stem loosening caused by cement failure. Although certain cementless stem designs have excellent long-term outcomes, cementless stems can loosen if a strong bond between bone and stem is not achieved.
Patients with large cementless stems may also experience a higher incidence of mild thigh pain. Likewise, polyethylene wear, particulate debris, and the resulting osteolysis (dissolution of bone) remain problems in both cemented and uncemented designs. Improvements in the wear characteristics of newer polyethylene and the advent of hard bearings (metal-on-metal or ceramic) may help resolve some of these problems in the future.
Although some orthopaedic surgeons are now using cementless devices for all patients, cementless total hip replacement is most often recommended for younger, more active patients and patients with good bone quality where bone ingrowth into the components can be predictably achieved. Individuals with juvenile inflammatory arthritis may also be candidates, even though the disease may restrict their activities.
Hybrid Total Hip ReplacementA hybrid total hip replacement has one component, usually the acetabular socket, inserted without cement, and the other component, usually the femoral stem, inserted with cement. This technique was introduced in the early 1980s, so long-term results are just now being measured. A hybrid hip takes advantage of the excellent track records of cementless hip sockets and cemented stems.
Partial Hip ReplacementsIf only one part of the joint is damaged or diseased, a partial hip replacement may be recommended. In most instances, the acetabulum is left intact and the head of the femur is replaced, using components similar to those used in a total hip replacement. The most common form of partial hip replacement is called a bipolar prosthesis.
Hip ResurfacingA newer technique for hip replacement that has recently emerged is called hip resurfacing. In this procedure, the socket is replaced similar to a total hip replacement. The femur, however, is covered or "resurfaced" with a hemispherical component. This fits over the head of the femur and spares the bone of the femoral head and the femoral neck. It is fixed to the femur with cement around the femoral head and has a short stem that passes into the femoral neck.
Hip resurfacing is an emerging procedure, most commonly performed in younger patients. It is too early to assess the long-term success of this procedure.
Longevity and OutcomesHip replacement operations are highly successful in relieving pain and restoring movement. However, the ongoing problems with wear and particulate debris may eventually necessitate further surgery, including replacing the prosthesis (revision surgery). Men and patients who weigh more than 165 lb have higher rates of failure. The chance of a hip replacement lasting 20 years is approximately 80%
Implant Construction
Implant Insertion
Cemented Total Hip Replacement
Cementless Total Hip Replacement
Hybrid Total Hip Replacement
Partial Hip Replacements
Hip Resurfacing
Longevity and Outcomes Total hip joint replacement is an orthopaedic success story, enabling hundreds of thousands of people to live fuller, more active lives.
Using metal alloys, high-grade plastics, and polymeric materials, orthopaedic surgeons can replace a painful, dysfunctional joint with a highly functional, long-lasting prosthesis.
Over the past half-century, there have been many advances in the design, construction, and implantation of artificial hip joints, resulting in a high percentage of successful long-term outcomes.
Implant DesignThe hip joint is called a ball-and-socket joint because the spherical head of the thighbone (femur) moves inside the cup-shaped hollow socket (acetabulum) of the pelvis.
To duplicate this action, a total hip replacement implant has three parts: the stem, which fits into the femur; the ball, which replaces the spherical head of the femur; and the cup, which replaces the worn out hip socket. Each part comes in various sizes to accommodate various body sizes and types.
In some designs, the stem and ball are one piece; other designs are modular, allowing for additional customization in fit.
Several manufacturers make hip implants. The brand used by your doctor or hospital depends on many factors, including your needs (based on your age, weight, bone quality, activity level, and health), the doctor's experience and familiarity with the device, and the cost and performance record of the implant. These are issues you may wish to discuss with your doctor.
Implant ConstructionMany people credit Sir John Charnley, a British orthopaedist, with performing the first modern total hip replacement. His innovations included combining a metal stem and ball with a plastic shell and using a methacrylate cement to hold the devices in place.
Today, the stem portions of most hip implants are made of titanium- or cobalt/chromium-based alloys. They come in different shapes and some have porous surfaces to allow for bone ingrowth.
Cobalt/chromium-based alloys or ceramic materials (aluminum oxide or zirconium oxide) are used in making the ball portions, which are polished smooth to allow easy rotation within the prosthetic socket.
The acetabular socket can be made of metal, ultra-high molecular-weight polyethylene, or a combination of polyethylene backed by metal.
All together, these components weigh between 14 and 18 ounces, depending on the size needed.
All the materials used in a total hip replacement have four characteristics in common:
•They are biocompatible. They can function in the body without creating either a local or a systemic rejection response.
•They are resistant to corrosion, degradation, and wear. Therefore, they will retain their strength and shape for a long time. Resistance to wear is particularly significant in maintaining proper joint function and preventing the further destruction of bone caused by particulate debris generated as the implant parts move against each other.
•They have mechanical properties that duplicate the structures they are intended to replace. For example, they are strong enough to withstand weight-bearing loads, flexible enough to bear stress without breaking, and able to move smoothly against each other as required.
•They meet the highest standards. These high standards extend to fabrication and quality control at a reasonable cost.
Top of page
Implant InsertionDuring a total hip replacement surgery, the orthopaedic surgeon will take a number of measurements to ensure proper prosthesis selection, limb length, and hip rotation. After making the incision, the surgeon works between the large hip muscles to gain access to the joint.
The femur is pushed out of the socket, exposing the joint cavity. The deteriorated femoral head is removed.
The acetabulum is prepared by cleaning and enlarging it with circular reamers of gradually increasing size. The new acetabular shell is implanted securely within the prepared hemispherical socket. The plastic inner portion of the implant is placed within the metal shell and fixed into place.
Next, the femur is prepared to receive the stem. The hollow center portion of the bone is cleaned and enlarged, creating a cavity that matches the shape of the implant stem. The top end of the femur is planed and smoothed so the stem can be inserted flush with the bone surface. If the ball is a separate piece, the proper size is selected and attached. Finally, the ball is seated within the cup so the joint is properly aligned and the incision is closed.
Hip replacements may be cemented, cementless, or hybrid (a combination of cemented and cementless components), depending on the type of fixation used to hold the implant in place. Although there are certain general guidelines, your surgeon will evaluate your particular situation carefully before making any decisions. Do not hesitate to ask which type of implant will be used in your situation and why that choice is appropriate for you.
Cemented Total Hip ReplacementOver the past 40 years, there have been many improvements in both the materials and the methods used to hold the femoral and acetabular components in place. Today, the most commonly used bone cement is an acrylic polymer called polymethylmethacrylate (PMMA).
A patient with a cemented total hip replacement can put full weight on the limb and walk without support almost immediately after surgery, resulting in a faster rehabilitation. Although cemented implants have a long and distinguished track record of success, they are not ideal for everyone.
Cemented fixation relies on a stable interface between the prosthesis and the cement and a solid mechanical bond between the cement and the bone. Today's metal alloy stems rarely break, but they can occasionally loosen. Two processes, one mechanical and one biological, can contribute to loosening.
•In the femoral component, cracks (fatigue fractures) in the cement that occur over time can cause the prosthetic stem to loosen and become unstable. This occurs more often with patients who are very active or very heavy. The action of the metal ball against the polyethylene cup of the acetabular component creates polyethylene wear debris. The cement or polyethylene debris particles generated can then trigger a biologic response that further contributes to loosening of the implant and sometime to loss of bone around the implant.
•The microscopic debris particles are absorbed by cells around the joint and initiate an inflammatory response from the body, which tries to remove them. This inflammatory response can also cause cells to remove bits of bone around the implant, a condition called osteolysis. As the bone weakens, the instability increases. Bone loss can occur around both the acetabulum and the femur, progressing from the edges of the implant.
Despite these recognized failure mechanisms, the bond between cement and bone is generally very durable and reliable. Cemented total hip replacement is more commonly recommended for older patients, for patients with conditions such as rheumatoid arthritis, and for younger patients with compromised health or poor bone quality and density. These patients are less likely to put stresses on the cement that could lead to fatigue fractures.
Cementless Total Hip ReplacementIn the 1980s, new implant designs were introduced to attach directly to bone without the use of cement. In general, these designs are larger and longer than those used with cement.
They also have a surface topography that is conducive to attracting new bone growth. Most are textured or have a surface coating around much of the implant so that the new bone actually grows into the surface of the implant. Because they depend on new bone growth for stability, cementless implants require a longer healing time than cemented replacements.
The orthopaedic surgeon must be very precise in preparing the femur for a cementless impact. The implant channel must match the shape of the implant itself very closely. New bone growth cannot bridge gaps larger than 1 mm to 2 mm.
Your surgeon may recommend a period of protected weight-bearing (using crutches or a walker) to give the bone time to attach itself to the implant. This protected weight bearing helps to ensure there is no movement between the implant and bone so a durable connection can be established.
Cementless femoral components tend to be much larger at the top, with more of a wedge shape. This design enables the strong surface (cortex) of the bone and the dense, hard spongy (cancellous) bone just below it to provide support.
The acetabular component of a cementless total hip replacement also has a coated or textured surface to encourage bone growth into the surface. Depending on the design, these components may also use screws through the cup or spikes, pegs, or fins around the rim to help hold the implant in place until the new bone forms. Usually these components have a metal outer shell and a polyethylene liner.
The pelvis is prepared for a cementless acetabular component using a process similar to that used in a cemented total hip replacement procedure. The intimate contact between the component and bone is crucial to permit bone ingrowth.
Initially, it was hoped that cementless total hip replacement would eliminate the problem of bone resorption or stem loosening caused by cement failure. Although certain cementless stem designs have excellent long-term outcomes, cementless stems can loosen if a strong bond between bone and stem is not achieved.
Patients with large cementless stems may also experience a higher incidence of mild thigh pain. Likewise, polyethylene wear, particulate debris, and the resulting osteolysis (dissolution of bone) remain problems in both cemented and uncemented designs. Improvements in the wear characteristics of newer polyethylene and the advent of hard bearings (metal-on-metal or ceramic) may help resolve some of these problems in the future.
Although some orthopaedic surgeons are now using cementless devices for all patients, cementless total hip replacement is most often recommended for younger, more active patients and patients with good bone quality where bone ingrowth into the components can be predictably achieved. Individuals with juvenile inflammatory arthritis may also be candidates, even though the disease may restrict their activities.
Hybrid Total Hip ReplacementA hybrid total hip replacement has one component, usually the acetabular socket, inserted without cement, and the other component, usually the femoral stem, inserted with cement. This technique was introduced in the early 1980s, so long-term results are just now being measured. A hybrid hip takes advantage of the excellent track records of cementless hip sockets and cemented stems.
Partial Hip ReplacementsIf only one part of the joint is damaged or diseased, a partial hip replacement may be recommended. In most instances, the acetabulum is left intact and the head of the femur is replaced, using components similar to those used in a total hip replacement. The most common form of partial hip replacement is called a bipolar prosthesis.
Hip ResurfacingA newer technique for hip replacement that has recently emerged is called hip resurfacing. In this procedure, the socket is replaced similar to a total hip replacement. The femur, however, is covered or "resurfaced" with a hemispherical component. This fits over the head of the femur and spares the bone of the femoral head and the femoral neck. It is fixed to the femur with cement around the femoral head and has a short stem that passes into the femoral neck.
Hip resurfacing is an emerging procedure, most commonly performed in younger patients. It is too early to assess the long-term success of this procedure.
Longevity and OutcomesHip replacement operations are highly successful in relieving pain and restoring movement. However, the ongoing problems with wear and particulate debris may eventually necessitate further surgery, including replacing the prosthesis (revision surgery). Men and patients who weigh more than 165 lb have higher rates of failure. The chance of a hip replacement lasting 20 years is approximately 80%
Minimally Invasive Total Hip Replacement
Minimally Invasive Total Hip ReplacementOsteoarthritis and Hip Replacement
Symptoms
Treatment for Osteoarthritis
Types of Hip Replacement
Research on the Horizon Total hip replacement is a common orthopaedic procedure. As the population ages, it is expected to become even more common. Hip replacement surgery involves removing the head of the thighbone (femur) and replacing the ball-and-socket mechanism of the hip with artificial implants. This relieves pain and improves mobility.
Minimally invasive hip replacement allows the surgeon to perform the hip replacement through one or two small incisions. Patients usually have less pain compared with traditional hip replacement surgery, and rehabilitation is faster.
Osteoarthritis and Hip ReplacementOsteoarthritis of the hip is the most common reason for a hip replacement. Osteoarthritis is caused by the wear and tear of aging. It causes the cartilage covering the joint surfaces to wear out, resulting in pain and stiffness.
Other conditions that can cause destruction of the hip joint include loss of the blood supply to the head of the thighbone (osteonecrosis), rheumatoid arthritis, injury, infection, and developmental abnormalities of the hip. Patients with arthritis may also have brittle bones (osteoporosis), but there is no direct relationship between bone density and the development of arthritis of the hip.
Top of page
SymptomsHip arthritis typically causes pain that is dull and aching. The pain may be constant or it may come and go. Pain may be felt in the groin, thigh, and buttock, or there may be referred pain to the knee. Walking, especially for longer distances, may cause a limp.
Some patients may need a cane, crutch, or walker to help them get around. Pain usually starts slowly and worsens with time and higher activity levels.
Patients with hip arthritis may have difficulty climbing stairs. Dressing, tying shoes, and clipping toenails can be difficult or impossible. Pain may also interfere with sleep.
See your doctor to diagnose hip arthritis. The doctor will inquire about your symptoms and perform a physical examination. X-rays may show loss of the cartilage space in the hip socket and a "bone-on-bone" appearance. Bone spurs and bone cysts are common.
Sometimes, the doctor may recommend additional tests to confirm the diagnosis, including magnetic resonance imaging (MRI) or computed tomography (CT) scans.
Top of page
Treatment for OsteoarthritisNonsurgical Treatment
For hip arthritis, the first treatment a doctor may recommend is over-the-counter, anti-inflammatory medications, such as ibuprofen. Some nutritional supplements, including glucosamine, may also provide some relief. Short-term physical therapy may help improve strength and reduce stiffness.
For patients with more advanced arthritis, use of a cane opposite the affected hip can help transfer weight away from the painful hip and improve walking ability. A walker can also be used. Arthritis, however, is progressive. Even with treatment, it will worsen over time. Weight loss can help decrease stresses on all of the joints.
Surgical Treatment
Pain and mobility may worsen with hip osteoarthritis, even when all of the recommended nonsurgical treatments have been tried. If this happens, the doctor may recommend surgery. Surgical options include:
•Arthroscopy. Arthroscopy of the hip is a minimally invasive, outpatient procedure that is relatively uncommon. The doctor may recommend it if the hip joint shows evidence of torn cartilage or loose fragments of bone or cartilage.
•Osteotomy. Candidates for osteotomy include younger patients with early arthritis, particularly those with an abnormally shallow hip socket (dysplasia). The procedure involves cutting and realigning the bones of the hip socket and/or thighbone to decrease pressure within the joint. In some people, this may delay the need for replacement surgery for 10 to 20 years.
Top of page
Types of Hip ReplacementTraditional Hip Replacement
Traditional hip replacement surgery involves making a 10- to 12-inch incision on the side of the hip. The muscles are split or detached from the hip, allowing the hip to be dislocated.
Once the joint has been opened up and the joint surfaces exposed, the surgeon removes the ball at the top of the thighbone, or femur. The hip socket is prepared by removing any remaining cartilage and some of the surrounding bone. A cup-shaped implant is then pressed into the bone of the hip socket. It may be secured with screws. A smooth plastic bearing surface is then inserted into the implant so the joint can move freely.
Next, the femur is prepared. A metal stem is placed into the femur to a depth of about 6 inches. The stem implant is either fixed with bone cement or is implanted without cement. Cementless implants have a rough, porous surface. It allows bone to adhere to the implant to hold it in place. A metallic ball is then placed on the top of the stem. The ball-and-socket joint is recreated.
Minimally Invasive Hip Replacement
Minimally invasive hip replacement surgery allows the surgeon to perform the hip replacement through one or two smaller incisions.
Candidates for minimal incision procedures are typically thinner, younger, healthier, and more motivated to have a quick recovery compared with patients who undergo the traditional surgery.
Before you decide to have a minimally invasive hip replacement, get a thorough evaluation from your surgeon. Discuss with him or her the risks and benefits. Both traditional and minimally invasive hip replacement procedures are technically demanding. They require that the surgeon and operating team have considerable experience.
Technique
The artificial implants used for the minimally invasive hip replacement procedures are the same as those used for traditional hip replacement. Specially designed instruments are needed to prepare the socket and femur and to place the implants properly.
The surgical procedure is similar, but there is less soft-tissue dissection. A single minimally invasive hip incision may measure only 3 to 6 inches. It depends on the size of the patient and the difficulty of the procedure.
The incision is usually placed over the outside of the hip. The muscles and tendons are split or detached, but to a lesser extent than in the traditional hip replacement operation. They are routinely repaired after the surgeon places the implants. This encourages healing and helps prevent dislocation of the hip.
Two-incision hip replacement involves making a 2- to 3-inch incision over the groin for placement of the socket. A 1- to 2-inch incision is made over the buttock for placement of the stem.
To perform the two-incision procedure, the surgeon may need guidance from X-rays. It may take longer to perform this surgery than it does to perform traditional hip replacement surgery.
Benefits
Reported benefits of less invasive hip replacement include:
•Less pain
•More cosmetic incisions
•Less muscle damage
•Rehabilitation is faster
•Hospital stays are shorter
For traditional hip replacement, hospital stays average 4 to 5 days. Many patients need extensive rehabilitation afterward. With less-invasive procedures, the hospital stay may be as short as 1 or 2 days. Some patients can go home the day of surgery.
Early studies suggest that minimally invasive hip replacement surgery streamlines the recovery process, but the risks and long-term benefits of less-invasive techniques have not yet been documented.
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Research on the HorizonExtensive study and development are now underway to determine the long-term benefits of minimally invasive hip replacement. New technology for imaging and computer-assisted implant placement has been developed.
Surgical technique continues to be modified as experience with minimally invasive hip surgery grows. This will allow more precise reconstruction of the hip with less direct visualization. In addition, new implant designs and materials are being developed to facilitate hip surgery and prolong the lifespan of replacements.
Symptoms
Treatment for Osteoarthritis
Types of Hip Replacement
Research on the Horizon Total hip replacement is a common orthopaedic procedure. As the population ages, it is expected to become even more common. Hip replacement surgery involves removing the head of the thighbone (femur) and replacing the ball-and-socket mechanism of the hip with artificial implants. This relieves pain and improves mobility.
Minimally invasive hip replacement allows the surgeon to perform the hip replacement through one or two small incisions. Patients usually have less pain compared with traditional hip replacement surgery, and rehabilitation is faster.
Osteoarthritis and Hip ReplacementOsteoarthritis of the hip is the most common reason for a hip replacement. Osteoarthritis is caused by the wear and tear of aging. It causes the cartilage covering the joint surfaces to wear out, resulting in pain and stiffness.
Other conditions that can cause destruction of the hip joint include loss of the blood supply to the head of the thighbone (osteonecrosis), rheumatoid arthritis, injury, infection, and developmental abnormalities of the hip. Patients with arthritis may also have brittle bones (osteoporosis), but there is no direct relationship between bone density and the development of arthritis of the hip.
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SymptomsHip arthritis typically causes pain that is dull and aching. The pain may be constant or it may come and go. Pain may be felt in the groin, thigh, and buttock, or there may be referred pain to the knee. Walking, especially for longer distances, may cause a limp.
Some patients may need a cane, crutch, or walker to help them get around. Pain usually starts slowly and worsens with time and higher activity levels.
Patients with hip arthritis may have difficulty climbing stairs. Dressing, tying shoes, and clipping toenails can be difficult or impossible. Pain may also interfere with sleep.
See your doctor to diagnose hip arthritis. The doctor will inquire about your symptoms and perform a physical examination. X-rays may show loss of the cartilage space in the hip socket and a "bone-on-bone" appearance. Bone spurs and bone cysts are common.
Sometimes, the doctor may recommend additional tests to confirm the diagnosis, including magnetic resonance imaging (MRI) or computed tomography (CT) scans.
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Treatment for OsteoarthritisNonsurgical Treatment
For hip arthritis, the first treatment a doctor may recommend is over-the-counter, anti-inflammatory medications, such as ibuprofen. Some nutritional supplements, including glucosamine, may also provide some relief. Short-term physical therapy may help improve strength and reduce stiffness.
For patients with more advanced arthritis, use of a cane opposite the affected hip can help transfer weight away from the painful hip and improve walking ability. A walker can also be used. Arthritis, however, is progressive. Even with treatment, it will worsen over time. Weight loss can help decrease stresses on all of the joints.
Surgical Treatment
Pain and mobility may worsen with hip osteoarthritis, even when all of the recommended nonsurgical treatments have been tried. If this happens, the doctor may recommend surgery. Surgical options include:
•Arthroscopy. Arthroscopy of the hip is a minimally invasive, outpatient procedure that is relatively uncommon. The doctor may recommend it if the hip joint shows evidence of torn cartilage or loose fragments of bone or cartilage.
•Osteotomy. Candidates for osteotomy include younger patients with early arthritis, particularly those with an abnormally shallow hip socket (dysplasia). The procedure involves cutting and realigning the bones of the hip socket and/or thighbone to decrease pressure within the joint. In some people, this may delay the need for replacement surgery for 10 to 20 years.
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Types of Hip ReplacementTraditional Hip Replacement
Traditional hip replacement surgery involves making a 10- to 12-inch incision on the side of the hip. The muscles are split or detached from the hip, allowing the hip to be dislocated.
Once the joint has been opened up and the joint surfaces exposed, the surgeon removes the ball at the top of the thighbone, or femur. The hip socket is prepared by removing any remaining cartilage and some of the surrounding bone. A cup-shaped implant is then pressed into the bone of the hip socket. It may be secured with screws. A smooth plastic bearing surface is then inserted into the implant so the joint can move freely.
Next, the femur is prepared. A metal stem is placed into the femur to a depth of about 6 inches. The stem implant is either fixed with bone cement or is implanted without cement. Cementless implants have a rough, porous surface. It allows bone to adhere to the implant to hold it in place. A metallic ball is then placed on the top of the stem. The ball-and-socket joint is recreated.
Minimally Invasive Hip Replacement
Minimally invasive hip replacement surgery allows the surgeon to perform the hip replacement through one or two smaller incisions.
Candidates for minimal incision procedures are typically thinner, younger, healthier, and more motivated to have a quick recovery compared with patients who undergo the traditional surgery.
Before you decide to have a minimally invasive hip replacement, get a thorough evaluation from your surgeon. Discuss with him or her the risks and benefits. Both traditional and minimally invasive hip replacement procedures are technically demanding. They require that the surgeon and operating team have considerable experience.
Technique
The artificial implants used for the minimally invasive hip replacement procedures are the same as those used for traditional hip replacement. Specially designed instruments are needed to prepare the socket and femur and to place the implants properly.
The surgical procedure is similar, but there is less soft-tissue dissection. A single minimally invasive hip incision may measure only 3 to 6 inches. It depends on the size of the patient and the difficulty of the procedure.
The incision is usually placed over the outside of the hip. The muscles and tendons are split or detached, but to a lesser extent than in the traditional hip replacement operation. They are routinely repaired after the surgeon places the implants. This encourages healing and helps prevent dislocation of the hip.
Two-incision hip replacement involves making a 2- to 3-inch incision over the groin for placement of the socket. A 1- to 2-inch incision is made over the buttock for placement of the stem.
To perform the two-incision procedure, the surgeon may need guidance from X-rays. It may take longer to perform this surgery than it does to perform traditional hip replacement surgery.
Benefits
Reported benefits of less invasive hip replacement include:
•Less pain
•More cosmetic incisions
•Less muscle damage
•Rehabilitation is faster
•Hospital stays are shorter
For traditional hip replacement, hospital stays average 4 to 5 days. Many patients need extensive rehabilitation afterward. With less-invasive procedures, the hospital stay may be as short as 1 or 2 days. Some patients can go home the day of surgery.
Early studies suggest that minimally invasive hip replacement surgery streamlines the recovery process, but the risks and long-term benefits of less-invasive techniques have not yet been documented.
Top of page
Research on the HorizonExtensive study and development are now underway to determine the long-term benefits of minimally invasive hip replacement. New technology for imaging and computer-assisted implant placement has been developed.
Surgical technique continues to be modified as experience with minimally invasive hip surgery grows. This will allow more precise reconstruction of the hip with less direct visualization. In addition, new implant designs and materials are being developed to facilitate hip surgery and prolong the lifespan of replacements.
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