EAST LANSING, Mich., Nov. 30 (UPI) -- Patients who are given a periarticular injection rather than a femoral nerve block before a total knee replacement surgery required less physical therapy and spent less time recovering in the hospital, researchers found in a recent study.
Femoral nerve blocks involve inserting a needle near the hip in order to deliver anesthesia, and are used for surgery on either of the legs. The blocks temporarily disrupt a patient's muscle control.
Researchers at the Greater Lansing Medical Center and Michigan State University found in a study, published in the Journal of the American Osteopathic Association, that using a periarticular injection -- anesthetics injected around the surgical site, rather than to an entire limb -- allows patients to recover more quickly because they retain control of their muscles.
After knee surgery, patients must bear weight on the new knee within 12 to 24 hours and start physical therapy. Femoral nerve blocks can affect the motor and sensory functions of the nerve for about 24 hours, making physical therapy more difficult, if not delaying it.
"Periarticular injections, unlike femoral nerve blocks, allow patients to maintain control of the quadriceps muscles. The tenants of osteopathic medicine tell us that function follows form, so enabling the quadriceps to fully engage helps patients to get up and begin walking independently faster," Dr. Brandon Horn, a surgeon at McLaren Greater Lansing Medical Center, said in a press release. "There's also a preventative component at work, since femoral nerve blocks are also associated with a high incidence of postoperative falls."
In the study, researchers reviewed records for 16 patients who underwent bilateral knee replacement in two separate surgeries where they received a femoral nerve block during the first surgery and a perarticular injection at the second. The patients in the study had a mean age of 63.8, 14 of them were women, and on average they waited 2.3 years between surgeries.
The researchers found patients receiving the injection required an average of 2.3 of in patient physical therapy sessions, while they needed 3.5 sessions after receiving a femoral nerve block. The patients also stayed in the hospital for about a half-day less.
"To treat knee replacement patients with a nerve block, you're looking at about $400 in additional costs for the procedure alone compared to that of the analgesic injection," Horn said. "Adding in the cost of additional physical therapy needed and extended hospital stay, the injection can save around $1,615 per patient."