Study finds MAC-STILA technique does not hinder operative workflow in geriatric hip fracture management

A study presented at the AAOS 2025 Annual Meeting investigated whether the MAC-STILA (monitored anesthesia care and soft-tissue infiltration with local anesthetic) technique during geriatric hip-fracture care affects intraoperative workflow efficiency. Study senior author Sanjit R. Konda, MD, FAAOS, associate professor in the Department of Orthopaedic Surgery at NYU Langone Health, spoke with AAOS Now Editorial Board member Bradley Lezak, MD, MPH, about the technique, its origins, and the team’s findings.

MAC-STILA combines two approaches to anesthesia. First, monitored anesthesia care involves administration of medication by an anesthesiologist and vital-sign monitoring, which differentiates this technique from standard sedation, Dr. Konda noted. Under monitored anesthesia care, patients can be brought between light sedation, deep sedation, and general anesthesia as needed.

Next, soft-tissue infiltration involves local anesthesia administered by the surgeon directly into the surgical site before incisions are made. The local anesthetic is applied to the standard incision locations, which can be marked ahead of time. Dr. Konda added, “Sometimes you can even do into the fracture site for a hematoma block.”

Origins and early data
Dr. Konda explained that the MAC-STILA technique was developed by his team in 2020 during the COVID-19 pandemic, when complications from the virus made it difficult to safely treat patients with hip fractures with general or spinal anesthesia.

“New York City was an epicenter for COVID,” Dr. Konda recalled. “We were still seeing [patients with] hip fractures that kept coming in, but the patients were really too sick — to the point where we didn’t want to intubate the patients because we didn’t think we could get them off the ventilator.”

Additionally, patients with COVID-19 were often hypercoagulable and on a therapeutic dose of anticoagulants, which ruled out spinal anesthesia.

“We couldn’t do general anesthesia. We couldn’t do spinal anesthesia. At our hospital out in Queens, one of the things we had available to us was soft-tissue infiltration. We started doing it on a handful of patients. We saw that patients were actually doing better overall,” Dr. Konda said.

After seeing early positive results with the technique, Dr. Konda and his team decided to expand their research. The initial pilot series included 20 to 30 patients matched with a cohort who had undergone general anesthesia and spinal anesthesia. The research team observed that during surgery, patients in the MAC-STILA cohort had more stable vital signs, such as heart rate and blood pressure. Postoperatively, they required less pain medication and had lower overall pain scores compared with both the general anesthesia and spinal anesthesia cohorts. The initial pilot study also revealed that patients’ mental status was less altered after surgery in the MAC-STILA cohort.

MAC-STILA and workflow efficiency
For their retrospective study presented at AAOS 2025, Dr. Konda and colleagues analyzed 395 patients with surgically treated hip fractures between January 2019 and January 2023 from a single institute. Fractures were Orthopaedic Trauma Association type 31A or 31B and fixed with screws, short or long nails, or plates. Seventy-nine patients received MAC-STILA, 158 received spinal anesthesia, and 158 received general anesthesia. Time to start of anesthesia, time under anesthesia, and total OR time were measured to calculate workflow efficiency.

The team found that the MAC-STILA cohort experienced the shortest time to start of anesthesia (12.57 minutes) and the shortest total OR time (100.75 minutes). There was no significant difference in time under anesthesia between cohorts.

Dr. Konda noted that, although this study did not look directly at cost data, increased time in the OR typically means increased costs. “What we found with our study … is that the overall workflow efficiency of the MAC-STILA technique seems to be better than general and spinal anesthesia with regard to total operative time, which is really the key,” he explained.

“The question is, why is it better?” Dr. Konda considered. “I think the main reason is that MAC-STILA is much more of a coordinated orchestra between the orthopaedic surgeon and the anesthesiologist. There’s a lot of communication that happens between the surgeon and the anesthesiologist as the patient comes into the room … and I think that is really decreasing the overall operative time.”

Future research
Although more research into the cost:benefit ratio of this technique is likely in the future, the initial pilot study’s finding of improved postoperative mental status with MAC-STILA has captured the team’s interest.

“That’s the direction our research has gone now, because postoperative delirium in particular is a huge problem for hip fracture patients,” Dr. Konda said, as postoperative delirium is not only costly to the health system but negatively impacts patient outcomes.

“We are expanding the study to now look at a multicenter trial, hopefully to figure out if MAC-STILA compared to general anesthesia can decrease the incidence of postoperative delirium,” he shared.

Heather Knox is the associate editor of AAOS Now. She can be reached at hknox@aaos.org.