Patients undergoing anterior cruciate ligament reconstruction (ACLr) may experience better long-term outcomes with a combined anesthesia approach, according to a recent study published in BMC Anesthesiology. The research, which analyzed data from over 63,000 adults, suggests that utilizing both regional and general anesthesia during the procedure is associated with lower rates of revision surgery, reduced opioid dependence, and less persistent pain compared to using either technique alone.

ACL injuries are a common knee ailment in the United States, with over 100,000 cases occurring annually. ACLr is often recommended to restore stability to the knee, and the number of these procedures has been increasing alongside the incidence of these injuries. Traditionally, patients have received either general anesthesia, regional anesthesia, or a combination of the two, with the choice often based on individual patient factors and the practices of the surgical team.

Study Details and Findings

The retrospective cohort study, led by Priti G. Dalal, MD, and colleagues at the Pennsylvania State Health Milton S. Hershey Medical Center, utilized the TriNetX Global Collaborative Network to identify 63,238 adults who underwent ACLr between January 2014 and January 2024. Patients were categorized based on the anesthetic technique they received – general anesthesia, regional anesthesia, or a combination of both. Outcomes were then assessed over both short-term (one day to one month) and long-term (one day to one year) intervals. Researchers employed a 1:1 propensity score matching method to ensure a balanced comparison between groups, accounting for demographic and clinical variables.

In the short term, the study revealed that patients receiving general anesthesia alone experienced a higher risk of needing a revision ACLr (a risk ratio of 2.00, p=0.01), reported more postoperative pain (risk ratio of 1.56, p<0.01), and demonstrated increased opioid dependence (risk ratio of 1.96, p<0.01) compared to those who received combined anesthesia. However, the general anesthesia group also reported less knee stiffness (risk ratio of 0.49, p<0.01) and participated in less physical therapy (risk ratio of 0.87, p<0.01) during this initial recovery phase.

Patients receiving regional anesthesia alone also experienced higher levels of postoperative pain (risk ratio of 1.44, p=0.02) and received more opioid prescriptions (risk ratio of 1.16, p<0.01) than the combined anesthesia group. They also participated in less physical therapy (risk ratio of 0.62, p<0.01).

The benefits of combined anesthesia persisted into the long term. The general anesthesia group was more likely to require revision ACLr (p=0.01; risk ratio 1.30), experience long-term nonsteroidal anti-inflammatory drug (NSAID) use (p<0.01; risk ratio 2.35), report postprocedural pain (p<0.01; risk ratio 1.50), knee pain (p<0.01; risk ratio 1.29), and opioid dependence (p<0.01; risk ratio 1.75) compared to the combined anesthesia group. Similarly, the regional anesthesia group showed higher rates of revision ACLr (p=0.04; risk ratio 1.51), postprocedural pain (p<0.01; risk ratio 1.91), knee pain (p=0.38; risk ratio 1.09), and NSAID prescriptions (p=0.02; risk ratio 1.12) compared to the combined anesthesia cohort.

Interestingly, the study noted that patients receiving combined anesthesia engaged in physical therapy more frequently during the early weeks of recovery. The authors suggest this is a clinically meaningful finding, as early participation in physical therapy is a well-established factor in promoting functional recovery after ACLr, and better pain control may facilitate more effective engagement.

Implications and Context

The study authors emphasize that these findings align with current guidelines promoting multimodal analgesia and regional techniques for musculoskeletal surgery. Regional nerve blocks, such as femoral or adductor canal blocks, when combined with general anesthesia, can effectively reduce acute pain and decrease reliance on opioid medications. This, in turn, may lower the risk of developing chronic postsurgical pain. By facilitating earlier and more effective participation in physical therapy, these strategies may contribute to improved long-term outcomes and reduce the risk of revision surgery.

The researchers acknowledge that, as a retrospective database analysis, the study has certain limitations. Variations in coding practices could potentially affect the accuracy of exposure classification, and the dataset does not provide detailed information about the specific type or route of regional anesthesia administered. The TriNetX database lacks information on hospital-level factors and clinician expertise, which could also influence both anesthetic selection and patient outcomes. Despite statistical adjustments, the possibility of residual confounding remains.

Despite these limitations, the authors conclude that their analysis provides longitudinal evidence supporting the role of anesthetic technique in optimizing ACL reconstruction outcomes. The findings suggest that prioritizing combined anesthesia, when clinically appropriate, may lead to reduced long-term pain, decreased opioid dependence, and a lower risk of requiring revision surgery following ACLr.