OVT Video Features Novel MAC-STILA Technique for Analgesia in Hip Fracture Surgery

Editor’s note: The following article is a review of a video available via the AAOS Orthopaedic Video Theater (OVT). AAOS Now routinely reviews OVT Plus videos, which are vetted by topic experts and offer CME. For more information, visit aaos.org/OVT.

The incidence of hip fractures in the United States is estimated at nearly 400,000 annually, with an incidence rate of 487 per 100,000 persons. Roughly 50 percent of hip fractures are in patients older than 85 years. The number of hip fractures is expected to continue to rise, estimated to double by the year 2050 compared with 2018. Despite advances in technology and perioperative management, postoperative mortality rates remain high. Techniques that decrease perioperative risk are of special interest to surgeons who treat hip fractures. One such technique is described in an OVT video narrated by Sanjit R. Konda, MD, FAAOS.

The video describes a novel method of analgesia for hip fracture surgery described as the MAC-STILA technique. This combines monitored anesthesia care (MAC) with soft-tissue infiltration of local anesthetic (STILA). Dr. Konda describes the technique in detail, including a step-by-step protocol, summarized below. He also describes the benefits of this technique, in addition to initial results in a small cohort of patients treated with this technique.

What is MAC-STILA?
MAC is defined as light to moderate sedation providing analgesia titrated to a level that preserves spontaneous breathing and airway reflexes. The patient is not arousable to verbal stimuli but is arousable to noxious stimuli. Combining MAC with STILA is referred to as the MAC-STILA technique. This technique is an option for intertrochanteric fractures that can be fixed with a short intramedullary nail. With this technique, IV sedation is administered by the anesthesia provider, while soft-tissue infiltration is administered by the surgeon. A standard local anesthetic is used to infiltrate the tissues around the surgical site; this is not a peripheral nerve block (Fig. 1). The agent recommended by the authors is bupivacaine, dosed at 2.5 mg/kg, mixed with 100 cc normal saline as a volume expander.

The MAC-STILA protocol is broken down into five steps:

1. Patient enters the OR with peripheral IV in place.
2. MAC is given by the anesthesia provider with the patient on the hospital bed.
3. Patient is transferred to the fracture table and positioned.
4. The hip is prepped and incisions marked, local anesthetic is infiltrated, and the fracture is reduced with fluoroscopy.
5. The hip is prepped/draped, then surgery proceeds as usual.

Why use MAC-STILA?
MAC-STILA is a universally applied technique that is surgeon-controlled and easy to administer. It avoids some risks of general and spinal anesthesia. General anesthesia carries a higher risk for postoperative delirium and a higher risk among patients with pulmonary hypertension and significant lung disease. Spinal anesthesia is not recommended for patients who have taken anticoagulants within 24 to 48 hours of injury. Delaying surgery is not an option, as the risk of morbidity increases after 48 hours of injury. Additionally, spinal anesthesia carries a risk of ischemic stroke or myocardial infarction in patients with severe aortic stenosis. Additional benefits of MAC-STILA include decreased OR time, with this protocol averaging 45 minutes wheels-in to wheels-out of the OR.

Outcomes of the MAC-STILA technique have been investigated in a retrospective, case-control, propensity-matched feasibility study, in which MAC-STILA was found to have better maintenance of normal heart-rate parameters intraoperatively and consistently lower visual analog pain scale scores in the first 3 hours after surgery. Through 48 hours postoperatively, narcotic use was similar to spinal anesthesia and five times lower than general anesthesia. MAC-STILA was associated with similar postoperative delirium rates as spinal anesthesia and lower rates than general anesthesia, and there were no differences in 30-day mortality.

Potential pitfalls of the MAC-STILA technique include the possible need for increased sedation if the femoral canal needs to be reamed, and it is recommended that the surgeon let the anesthesia provider know in advance to prepare for this possibility. Additionally, the patient may respond to noxious stimuli and move slightly, which is a possibility during reaming. There is also a learning curve involved, and it may take a few cases for the anesthesia provider to determine the appropriate level of sedation for most patients.

MAC-STILA is an interesting new technique that may help decrease the risk associated with anesthesia in medically complex patients undergoing hip fracture surgery. It has shown promising results in a small series of short cephalomedullary nails in intertrochanteric femur fractures. This may be a useful addition to treatment protocols for orthopaedic surgeons treating hip fractures.

Leslie Schwindel, MD, FAAOS, is a general orthopaedic surgeon at Lake Cumberland Regional Hospital in Somerset, Kentucky, and a member of the AAOS Now Editorial Board.

References

1. Sing CW, Lin TC, Bartholomew S, et al: Global epidemiology of hip fractures: secular trends in incidence rate, post-fracture treatment, and all-cause mortality. J Bone Miner Res 2023;38(8):1064-75.
   Konda SR, Ranson RA, Dedhia N, et al: Monitored anesthesia care and soft-tissue infiltration with local anesthesia: an anesthetic option for high-risk patients with hip fractures. J Orthop Trauma 2021;35(10):542-9.