Osteoarthritis

Description

Surgery

Different surgical procedures are available as a final measure to relieve pain and increase function in osteoarthritis patients. Certain surgical procedures have been used to relieve pain if medications fail. Even with these procedures, however, joint replacement may still be needed later on.

Arthroscopy

Arthroscopy is performed to clean out bone and cartilage fragments that, in theory at least, may cause pain and inflammation.More than 650,000 of these procedures are done on osteoarthritic knees each year in the US, and about half of patients report less pain after the procedure. A rigorous 2002 trial, however, found that arthroscopic knee surgery was no more effective than sham surgery, in which surgeons only pretended to operate on the knee, for relief of osteoarthritic pain or stiffness. The study, which followed patients at a Veterans Affairs hospital for two years, has called into serious question whether the popular $5,000 procedure has any real benefits for osteoarthritis beyond what might be achieved by a placebo response. Research and debate continues on whether arthroscopy provides true benefits for those with osteoarthritis and, if so, which patients may most be helped by it.

Click the icon to see an illustrated series detailing knee arthroscopy surgery.

Joint Replacement (Arthroplasty)

When osteoarthritis becomes so severe that pain and immobility make normal functioning impossible, many people become candidates for artificial (prosthetic) joint implants using a procedure called arthroplasty. Hip replacement is the most established and successful replacement procedure, followed by knee replacement. Knee replacement, in fact, has a slightly better long-term success rate than hip replacement. Other joint surgeries (shoulders, elbows, wrists, fingers) are less common, and some arthritic joints (in the spine, for instance) cannot yet be treated in this manner. When two joints, such as both knees, need to be replaced, having the operations done sequentially rather than at the same time may result in fewer complications.

Click the icon to see an illustrated series detailing knee joint replacement surgery.

Candidates. The primary indications for surgery are pain and significant limitations of movement, including walking, that cannot be treated by less invasive therapies. Some experts are suggesting, however, that joint replacement should be considered earlier rather than as a last resort. They argue that patients who wait until they are severely disabled do not recover as completely as those who have the procedure earlier.

Patients who may not be good candidates are those with the following conditions:

• Severe neurologic, emotional, or mental disorders.
• Severe osteoporosis.
• Other chronic medical conditions.
• Obesity.

Surgeons often prefer to delay prosthetic implantation in patients aged 40 to 60 or younger, because implants wear out and they will require at least one revision procedure later on.Newer, more long-lasting materials, however, may help reduce the rate of re-operations. Of concern is evidence suggesting that the procedure is performed less often among African Americans. (Furthermore, the risk for arthritic knees is higher in African Americans, particularly women.)

Procedure Description. Although the following is mostly a description of hip replacement surgery, the principles are similar for other arthroplasties.

The surgeon removes the ball and socket joint that joins the pelvis and thigh bone (femur) and replaces it with an artificial joint (a prosthesis). It is composed of two pieces:

• A cup-like device fits in the hip socket (called the acetabula), which has been hollowed out. This ball-and-socket cup is positioned to form the new joint.
• A metal shaft, or stem, with a polished metal ball at the top, is inserted into the narrow center of the femur.

The prosthesis is usually made of a metal alloy and plastic. A ceramic implant may prove to last longer than other materials and be a safe option for younger patients.

There are different options available for attaching it to the adjoining bones:

• A cement made of polymethylmethacrylate (usually preferred for older patients who generally have thinner bones).
• So-called cementless implants, in which the prosthesis is coated with a porous material that allows bone to grow into and eventually adhere to the device (usually used for patients under 65, who are likely to need repeat surgery in their lifetime). Specific implants, such as the Mallory-Head, may prove to be more reliable than cement.

Click the icon to see an illustrated series detailing hip joint replacement surgery.

Complications. Complications can occur, and, although uncommon, some can be life-threatening. There is a 1% chance of death within three months of an initial procedure and a 2.6% risk after a repeat procedure. The risks are highest in the first three months. Those at highest risks for complications are elderly adults, men (compared to women), African Americans, people with lower income, and those with serious medical conditions.

Specific complications include the following:

• Deep blood clots (known as deep vein thrombosis) and pulmonary embolism. Deep blood clots can develop in the legs after this surgery. This poses a risk (which is about 0.9%) for pulmonary embolism--a dangerous condition in which the clot travels to the lungs. Anticoagulant (blood thinning) therapy is important to prevent blood clots. This typically includes either warfarin or enoxaparin (Lovenox, a drug known as low-molecular weight heparin or LMWH). Others are being investigated. Anticoagulant therapy is given during the hospital stay, and studies suggest it may be beneficial when continued for several weeks at home. The patient also typically wears specially fitted elastic stockings to help prevent clots. Patients who are overweight are at higher than average risk for post-operative blood clots
• Infection. Wound infection occurs in about 0.2% of joint replacementsand requires prompt removal of the implant to treat the infection.A new prosthesis must then be re-implanted at a later time. Any pre-existing infection must be treated and cured before surgery is performed. (Older women should be aware of urinary tract infection symptoms, which may be a strong indicator for postponing surgery.) After surgery, patients should take certain precautions. For example, they should take antibiotics before invasive dental procedures or any other surgery. In such cases, bacteria may be introduced into the bloodstream and infect the areas around the artificial joints.
• Hip dislocation. This occurs in about 3.1% of first hip procedures. The rate is much higher (14.4%) in revision operations.

Click the icon to see an image of a dislocated hip.

• Pain. Thigh pain can occur after either hip replacement. For reasons still unclear, porous hip prostheses are more apt to produce thigh pain than cement implants, although advanced techniques using a tapered shaft are reducing this complication.
• Failure. The primary reason for implant failure is osteolysis (bone destruction) caused by long-term wear. The main source of wear is from tiny particles released from the prosthesis.
• Other complications. These include uneven leg lengths, nerve damage that can cause numbness or weakness, urinary tract infections, delayed healing, and allergic reactions to the metal. Long-term, there have been rare reports of a possible autoimmune response, in which certain immune system factors are tricked by loose particles released from the prosthetic device into attacking healthy cells. Any incidence of unexplained weight loss and fatigue may be symptoms of this uncommon event.

Rehabilitation. Aside from the surgeon's skilland the patient's underlying condition, the success rate depends on the kind and degree of activity the joint receives following replacement surgery.

The patient is urged and aided into getting out of bed and walking the day after surgery. Most hip replacement patients leave the hospital within a week and can walk with crutches within two to four weeks, recovering fully in about three months.

Physical therapy itself takes about six weeks to rebuild adjoining muscle and strengthen surrounding ligaments. Studies suggest that an exercise program started before surgery and resumed afterward can improve recovery. Continuous passive motion (CPM) is an effective regimen for knee replacement patients. It uses a mechanical device that slowly moves the joint through an arc of motion for an extended period of time. It is used to prevent scar tissue from developing. In one review, a combination of physical therapy and CPM were more beneficial than physical therapy alone.

Limitations After Surgery. While many patients find that joint replacement provides remarkable pain relief and restores some mobility, they need time to adjust to the artificial joint, and there are some limitations.

Limitations after hip surgery include the following:

• Usually patients with new hips are able to walk several miles a day and climb stairs, but they cannot run.
• Prosthetic hips should not be flexed beyond 90 degrees, so patients must learn new ways to perform activities requiring bending down (i.e., tying a shoe).

Limitations after knee surgery include the following:

• Walking distance improves in 80% of patients after knee replacement surgery, but patients still cannot run.
• Only slightly more than half of patients report improvement in stair climbing. (Artificial knee joints generally have a range of motion of just 110 degrees.)

Failure Rates. Joint replacement represents a great medical advance, but it is not failure proof. Infection is a major cause of early failure and always requires revision.Improper balancing of the ligaments and other tissues surrounding the joint and resulting poor joint stability are a common reason for failure of arthroplasties. Surgical expertise is important for avoiding this complication.Additional longer-term factors also come into play.

Older cement prostheses have a particularly high rate of bone loss and loosening, apparently largely due to cement deterioration. In general, studies are reporting reoperation rates of over 30% after 10 years. Fortunately, advances in cement and prosthetic implants are improving the implant survival rates and reducing the need for revision procedures.

Uncemented arthroplasty using porous material has been showing very good results for the hip, although it may be less successful for knee replacement. In fact, in spite of short term success, longer experience with this method suggests it may not be superior to cement prostheses. Failure of bone to grow into the porous material is a relatively common event, a problem that does not occur with cement prostheses. Some experts recommend cement implants over cementless ones for total knee arthroplasty.

Revision Arthroplasty

A repair procedure called arthroplasty revision may be used in cases where the original transplant fails. The specific procedure depends on whether the bone defects that occurred are contained or uncontained.

• Contained defects can be repaired with small bone grafts, the use of cement, or oversized cementless implants as required.
• Uncontained defects are more severe and may require a large bone graft or specially constructed implants to restore bone.

If a second arthroplasty is required, the potential for complications is magnified: more bone is cut, more blood is lost, and the operation takes longer. Patients are also generally older and more vulnerable to complications.

Other Joint Procedures

Resection Arthroplasty. In resection arthroplasty, a false joint of scar tissue is created. This procedure is used most often in treating arthritis of the foot.

Osteotomy. If only a certain section (the medial compartment) of the knee is damaged and deformed by osteoarthritis, the surgeon may choose to perform osteotomy:

• The knee is opened.
• A debridement (removal of damaged tissue) is performed in the joint to eliminate the loose or torn fragments that are causing pain and inflammation.
• The bone is then reshaped to remove the deformity.
• The procedure may ease symptoms and slow disease progression and is best used in heavier adults who are under 60 years old.

Hemicallotasis. Hemicallotasis is a procedure for the knee that may prove to be an effective and less invasive alternative to osteotomy. It is achieved by attaching the knee with pins to an external frame-like device that lengthens the deformed part of the knee over several weeks. The patient is mobile during this period. Infections at the pin site are the most common complications.

Arthrodesis. If the affected joint cannot be replaced, surgeons can perform a procedure called arthrodesis that eliminates pain by fusing the bones together. The patient must understand, however, that fusing the bones makes movement of the joint impossible. Bone fusion is most often done in the spine and in the small joints of the hands and feet.

Unicompartmental Knee Arthroplasty. Unicompartmental knee arthroplasty (also called unicondylar knee arthroplasty) may be a useful procedure in some cases of limited damage in the knee. It is intended to relieve pain and preserve function as long as possible before a total knee replacement is necessary. The procedure involves a small incision and insertion of small implants. It retains important knee ligaments, which should preserve more movement than a total knee replacement. The procedure is not widely available and is controversial, since the implants may not be as reliable as those in total knee replacement. In a 2003 German study, this approach failed to restore full functional capabilities in patients who had the procedure compared to their healthy peers.

Cartilage Transplants. An interesting technique called autologous chondrocyte implantation, also called chondroplasty or the Carticel approach, is being used for knees damaged by injuries. In this procedure, arthroscopy is used to first remove cartilage in eroded areas. The results have been good to excellent, although long term benefits are questionable. Whether it has any benefit for older patients with osteoarthritis is not yet known. Other cartilage transplant procedures are also under study.

Hip Resurfacing. An experimental surgical alternative to total hip replacement that is being used in Europe involves scraping the surfaces of the hip joint and femur and placing a metal cap over the bone. The procedure preserves much of the bone, so that a standard hip replacement can be done years down the road if needed. It may also allow for more stability, a faster recovery, and greater range of motion, making it a potentially good option for young, physically active patients.