Risk and Complication to Knee Replacement Surgery San Antonio

According to the American Academy of Orthopedic Surgeons (AAOS), "blood clots in the leg veins are the most common complication of knee replacement surgery. Your orthopedic surgeon will outline a prevention program, which may include periodic elevation of your legs, lower leg exercises to increase circulation, support stockings and medication to thin your blood."

Periprosthetic fractures are becoming more frequent with the aging patient population and can occur intraoperatively or postoperatively.

The knee at times may not recover its normal range of motion (0 - 135 degrees usually) after total knee replacement. Much of this is dependent on pre-operative function. Most patients can achieve 0 - 110 degrees, but stiffness of the joint can occur. In some situations, manipulation of the knee under anesthetic is used to improve post operative stiffness. There are also many implants from manufacturers that are designed to be "high-flex" knees, offering a greater range of motion.

In some patients, the kneecap is unstable post-surgery and dislocates to the outer side of the knee. This is painful and usually needs to be treated by surgery to realign the kneecap. However this is quite rare.

In the past, there was a considerable risk of the implant components loosening over time as a result of wear. As medical technology has improved however, this risk has fallen considerably. One implant manufacturer claims to have reduced this risk of wear by 79% in fixed-bearing knees. Another implant manufacturer claims to have reduced the risk of wear by 94% in mobile-bearing, also known as rotating platform, knees. Knee replacement implants can last up to 20 years in many patients; whether or not they actually survive that long depends largely in part upon how active the patient is after surgery.

Self Employed consumers need to be concerned about their health since they have little time to see doctors when a health problem occurs. Self Employed Texas Health Insurance is a must to keep you healthy.

Infection

The current classification of AAOS divides prosthetic infections into four types.

Type 1(Positive intraoperatively culture): 2 positive intraoperative cultures
Type 2(early postoperative infection): Infection occurring within first month after surgery
Type 3(acute hematogenous infection): Hematogenous seeding of site of previously well-functioning prosthesis
Type 4(late chronic infection): Chronic indolent clinical course; infection present for >1 month

While it is relatively rare, Periprosthetic infection remains one of the most challenging complications of joint Arthroplasty. A detailed clinical history and physical remain the most reliable tool to recognize a potential Periprosthetic infection. In some cases the classic signs of fever, chills, painful joint, and a draining sinus may be present, and diagnostic studies are simply done to confirm the diagnosis. In reality though, most patients do not present with those clinical signs, and in fact the clinical presentation may overlap with other complications such as aseptic loosening. In those cases diagnostic tests can be useful in confirming or excluding infection.

According to a recent review the following tests can be used in the diagnosis of a Periprosthetic infection.

Conventional radiograph: Rule out other conditions such as loosening and/or osteolysis.
Radionucleotide Imaging: Technetium-99m Sulfur imaging combined with indium-111-labeled leukocytes probably offers improved specificity than either test alone. Gallium 67 scans alone have low sensitivity for infection. FDG-PET imaging has been shown to have variable specificity and sensitivity.
Serology: Elevated serum C-reactive protein (CRP) and Erythrocyte Sedimentation Rate(ESR) more than three months following Arthroplasty are good screening tests.
Cultures: High sensitivity and specificity, but only if done two weeks following antibiotic discontinuation. Gram stains have low specificity and sensitivity. The predicitive value of a positive culture increases if the culture is performed in patient with high clinical suspicion, rather than a screening test.
Joint fluid leukocyte counts: A joint fluid white blood cell count of more than 500/μl is suggestive of an infection.
Frozen sections of implant membranes: More than five white blood cells/High power ield is indicative of infection.
Newer tests: Polymerase chain reactions involving the bacterial 16S rRNA have high rates of false positives because they can detect necrotic bacterial debris even in the absence of active infection.

None of the above laboratory tests has 100% sensitivity or specificity for diagnosing infection. Specificity improves when the tests are performed in patients in whom clinical suspicion exists. ESR and CRP remain good 1st line tests for screening (high sensitivity, low specificity). Aspiration of the joint remains the test with the highest specificity for confirming infection.

The choice of treatment depends on the type of prosthetic infection.

Positive intraoperative cultures: Antibiotic therapy alone
Early post-operative infections: debridement, antibiotics, and retention of prosthesis.
Late chronic: delayed exchange arthroplasty. Surgical débridement and parenteral antibiotics alone in this group has limited success, and standard of care involves exchange arthroplasty.
Acute hematogenous infections: debridement, antibiotic therapy, retention of prosthesis.

Appropriate antibiotic doses can be found at the following instructional course lecture by AAOS