Joint replacement surgeries have revolutionized the treatment of arthritis and allowed a generation of older adults to stay active for decades longer than their ancestors. Bone cement, which is used to fix joint replacement implants to bone, makes many of those surgeries possible, allowing surgeons to transfer body weight and service loads from the prosthesis to the bone and increase the joint’s weight-bearing capacity.
In an ongoing effort to prevent post-surgical infections, antibiotic-loaded bone cement was designed to allow for the implantation of infection-fighting drugs during surgery. Researchers have found varying results with standard and antibiotic-loaded bone cements, but some controversy exists regarding their use and efficacy. For many physicians, there’s no easy answer to the “With or without antibiotics?” question.
Procedure Determines Cement Choice
For example, at Nashville, Tennessee-based Southern Joint Replacement Institute (SJRI), orthopedic surgeon Craig Morrison, M.D., frequently uses bone cement—but he uses both antibiotic-loaded and standard, depending on the patient and the surgery.
“I cement 100 percent of my knee replacements and about 2 percent of my hip replacement stems,” he says. “For primary knee replacements, I rarely use antibiotics in the bone cement.”
Morrison avoids using antibiotic-loaded bone cement with most knee replacements because he doesn’t believe the research justifies the extra cost. “Most of the recent large studies looking retrospectively at historical data do not show a difference in infection rates when antibiotics are used in the cement,” he says.
An August 2014 Journal of Arthroplasty article showed no difference in infection rates in more than 3,000 knee replacements at different points in time up to one year after surgery. Additionally, the large Kaiser Permanente National Total Joint Replacement Registry has shown similar findings in over 20,000 knee replacements.
Though the research doesn’t warrant using antibiotic cement with all knee replacement surgeries, Morrison may opt to use it under certain circumstances. “Although somewhat controversial, it may be reasonable to choose to use antibiotic cement only in patients with a high risk of infection like inflammatory arthritis, morbid obesity or diabetes—likely the minority of patients in most practices,” he says. “Additionally, I use premixed antibiotic bone cement in my revision knee replacements.”
While he uses antibiotic-loaded cement sparingly with knee replacements, Morrison generally uses antibiotics in the bone cement for hip replacement surgeries. “The Norwegian Arthroplasty Register has shown a lower revision rate for infection and aseptic stem loosening in total hip arthroplasty patients who received antibiotic bone cement,” he says.
Weighing the Pros and Cons
The advantage of antibiotic-loaded bone cement is its ability to fight infection. At SJRI, the product is used most for infection treatment, especially when a joint replacement patient has developed an infection and a revision surgery must be performed. For instance, when Morrison performs a resection arthroplasty for a hip or knee infection, he puts in a temporary articulating spacer until the second stage revision. He adds 3 grams of the antibiotic Vancomycin and 2.4 grams of the antibiotic Tobramycin to each 40 grams of regular cement. On average, Morrison uses three packs of cement in these cases.
One of the arguments against using antibiotic-loaded bone cement is that the practice could potentially create antibiotic resistance. But based on research published in the Journal of Arthroplasty, Morrison says antibiotic resistance as a result of antibiotic cement does not appear to be a problem. Instead, the main issue is cost. Premixed antibiotic bone cement adds about $300 per case, “and it is difficult to justify this cost based on the literature specific to knee replacements,” he says.
While there is a place for antibiotic-loaded bone cement, ongoing cost pressures are leading some facilities and physicians to look more closely at each case before choosing to use it. “As surgeons become more engaged in cost-savings measures through bundle programs and aligned incentives with hospitals, I believe the routine use of antibiotic-laden cement will go down,” Morrison says.
Traditionally, HealthTrust provided a contract with a single supplier for bone cement. However, member hospitals continued to use a variety of different providers. A clinician member of the HealthTrust Physician Services team recently developed a clinical evidence review (CER) by combing through and summarizing the available clinical research and soliciting physician feedback.
The bone cement CER revealed that many orthopedic surgeons do not use antibiotic-loaded cement only or standard cement only; instead, they prefer to choose whatever option is best for each particular surgery or patient.
Other results from HealthTrust’s clinical evidence review:
- No randomized clinical trials compare standard or antibiotic-loaded bone cement.
- Use of antibiotic-loaded cement in knee replacement surgery is controversial except in high-risk patients.
- Bone cement is rarely used in total hip replacement surgeries, but the American Academy of Orthopaedic Surgeons recommends it for hip fracture patients.
- Physician preferences are not driven by clinical differentiation between products.
- Tinted or colored cement is preferred because it is easier to identify if the patient requires revision surgery.
- Higher viscosity cement is usually preferred for total knee replacements, and lower viscosity cement is required for total hip replacements.
- Pre-mixed, antibiotic-loaded bone cement should not be used for treating infected joint replacements because the antibiotic dose is intended for infection prophylaxis only.
- High-dose antibiotic bone cement spacers are used to treat active joint replacement infections.
In an effort to create value for facilities and respect physician needs and practice patterns, HealthTrust decided to implement a strategy that offers physicians more choices among bone cement suppliers that offer clinically equivalent products.
Bone cement from different suppliers can differ in color, viscosity, and presence and dosage of antibiotics. But in most cases, those differences can be left to physician preferences since the clinical outcomes are similar. However, prices of bone cement vary among suppliers and by facility. Without antibiotics, bone cement can cost between $40 and $185 per standard dose; with antibiotics, it can range from $117 to $663 per standard dose. Physicians now have more opportunities to select from contracted cements that best meet the individual needs of patients undergoing specific procedures.